1
of
69
June
26,
2006
EPA­
HSRB­
06­
01
George
Gray,
Ph.
D.
Science
Advisor
Office
of
the
Science
Advisor
1200
Pennsylvania
Avenue,
NW
Washington,
DC
20460
Subject:
April
4­
6,
2006
EPA
Human
Studies
Review
Board
Meeting
Report
Dear
Dr.
Gray:

The
United
States
Environmental
Protection
Agency
(
EPA
or
Agency)
requested
the
Human
Studies
Review
Board
(
HSRB)
to
provide
advice
on
Agency
scientific
and
ethics
reviews
of
completed
human
studies
concerning
the
following
pesticide
active
ingredients:
aldicarb,
amitraz,
azinphos­
methyl,
dichlorovos
(
DDVP),
ethephon,
methomyl,
oxamyl,
and
sodium
cyanide.
The
studies
reviewed
included
both
studies
on
which
the
Agency
proposed
to
rely
in
actions
under
the
pesticide
laws
and
studies
that
the
Agency
had
decided
not
to
use
in
its
risk
assessments,
either
for
ethical
or
scientific
reasons.
The
enclosed
HSRB
report
addresses
the
Board's
response
to
EPA
charge
questions
for
the
Board's
consideration
at
its
April
4­
6,
2006
meeting.

The
HSRB
was
extremely
impressed
with
the
high
quality
scientific
and
ethical
review
brought
before
the
Board.
A
summary
of
the
Board's
conclusions
on
the
scientific
and
ethical
considerations
of
the
human
toxicity
studies
for
the
eight
pesticides
under
review
are
provided
below.

Aldicarb
Scientific
considerations
 
The
cholinesterase
data
from
the
aldicarb
human
study
were
reliable
for
use
in
the
aldicarb
single
chemical,
aggregate
risk
assessment.

 
The
cholinesterase
data
from
the
aldicarb
human
toxicity
study
were
reliable
for
use
in
the
cumulative
risk
assessment
for
N­
methyl
carbamates.
2
of
69
Ethical
considerations
 
The
aldicarb
human
toxicity
study
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted,
however
 
There
was
no
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained
and
 
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted),
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

Methomyl
Scientific
Considerations
 
The
methomyl
human
study
could
be
appropriately
applied
to
the
inter­
species
risk
factor
for
methomyl
and
for
use
in
the
cumulative
risk
assessment
of
N­
methyl
carbamates.

Ethical
Considerations
 
The
methomyl
human
toxicity
study
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted,
however
 
There
was
no
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained,
and
 
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted),
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

Oxamyl
Scientific
Considerations
 
Although
the
Board
had
some
questions
about
the
Agency's
conclusions
regarding
lack
of
sex
difference
and
of
the
difference
between
brain
and
RBC
ChE
based
on
only
one
species,
the
Board
supported
the
Agency's
conclusion
that
there
were
no
study
deficiencies
identified
that
would
have
affected
the
outcome
or
conclusions
of
this
study.

 
Considering
the
high
quality
of
the
design
and
the
conduct
of
the
study,
the
Board
agreed
that
this
intentional
human
dosing
study
of
oxamyl
was
sufficiently
robust
to
be
used
for
reducing
the
10x
inter­
species
(
i.
e.
animal
to
human)
uncertainty
factor
in
the
cumulative
risk
assessment
for
the
N­
methyl
carbamates.
3
of
69
Ethical
Considerations
 
The
oxamyl
human
toxicity
study
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted,
however
 
There
was
no
clear
or
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained,
and
 
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted)
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

Azinphos­
Methyl
Scientific
Considerations
 
Data
from
the
28­
day
repeat
oral
dose
study
of
azinphos
methyl
should
not
be
used
in
developing
a
point
of
departure
for
extrapolation
of
risk
to
workers
exposed
to
azinphosmethyl
via
the
dermal
and
inhalation
routes.

 
Data
from
the
28­
day
repeat
oral
dose
study
of
azinphos­
methyl
cannot
be
used
to
inform
the
inter­
species
factor
in
the
cumulative
risk
assessment.

Ethical
Considerations
 
The
AZM
human
toxicity
study
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted,
however
 
There
was
no
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained,
and
 
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted)
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

DDVP
Scientific
Considerations
 
The
DDVP
repeat
dose
human
toxicity
study
was
sufficiently
robust
for
developing
a
point
of
departure
for
estimating
dermal,
incidental
oral,
and
inhalation
risk
from
exposure
to
DDVP
in
the
single
chemical
risk
assessment.

 
The
DDVP
repeat­
dose
human
toxicity
study
should
not
be
used
to
support
reducing
the
default
10X
inter­
species
factor
in
the
cumulative
risk
assessment
of
the
organophosphate
pesticides.
4
of
69
 
The
HSRB
concluded
that
the
other
DDVP
human
toxicity
studies
available
for
the
Board's
consideration
should
not
be
used
for
determining
a
reduction
in
the
10X
uncertainty
factor
to
derive
reference
dose
values
for
DDVP
based
on
animal
toxicity
endpoints.

Ethical
Considerations
 
The
DDVP
repeat
dose
oral
human
toxicity
study
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted,
however
 
There
was
no
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained,
and
 
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted)
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

Ethephon
Scientific
Considerations
 
The
Board
concluded
that
the
scientific
quality
of
either
the
ethephon
28
day
oral
toxicity
study
or
the
ethephon
16
day
human
oral
toxicity
study
was
not
adequate
on
its
own.
The
16
day
study
can
be
used
to
inform
the
ethephon
28
day
human
oral
toxicity
study.
The
Board
approved
the
28
day
study
for
use
in
EPA
risk
assessments,
emphasizing
that
the
dose
level
administered
is
almost
certainly
not
the
lowest
dose
at
which
adverse
effects
are
likely
to
be
observed.
However,
its
use
in
lieu
of
the
animal
studies
will
result
in
greater
protection
for
exposed
human
populations.

Ethical
Considerations
 
Both
the
28
and
16
day
oral
human
toxicity
studies
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted,
however
 
There
was
no
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained,
and
 
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted),
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

Sodium
Cyanide
Scientific
Considerations
5
of
69
 
Data
from
the
amygdalin
trial
could
be
used
for
establishing
a
point
of
departure
in
the
acute
dietary
risk
assessment
for
sodium
cyanide.

Ethical
Considerations
 
The
sodium
cyanide
human
oral
toxicity
study
appeared
to
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted
 
There
was
no
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained
 
There
was
no
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted)
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

Amitraz
Scientific
Considerations
 
The
results
from
the
single
oral
dose
study
were
informed
by
the
human
metabolism
study
such
that
the
single
oral
dose
study
was
appropriate
for
developing
a
point
of
departure
for
acute
dietary
risk.

 
The
combined
results
from
the
single
oral
dose
study
and
the
human
metabolism
study
were
not
appropriate
for
developing
a
point
of
departure
for
chronic
dietary
risk,
shortterm
oral
exposure,
or
inhalation
risk.

 
The
majority
of
the
Board
concluded
that
the
human
dermal
study
was
not
appropriate
for
developing
a
point
of
departure
for
dermal
exposures
of
various
durations.

Ethical
Considerations
 
The
amitraz
acute
oral
and
dermal
human
toxicity
studies
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted,
however
 
There
was
no
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained,
and
 
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted),
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

In
conclusion,
the
EPA
HSRB
appreciated
the
opportunity
to
advise
the
Agency
on
the
scientific
and
ethical
aspects
of
human
subjects
and
looks
forward
to
future
opportunities
to
continue
advising
the
Agency
in
this
endeavor.
6
of
69
Sincerely,

Celia
Fisher,
Ph.
D.
Chair
EPA
Human
Studies
Review
Board
7
of
69
NOTICE
This
report
has
been
written
as
part
of
the
activities
of
the
EPA
Human
Studies
Review
Board,
a
Federal
advisory
committee
providing
advice,
information
and
recommendations
on
issues
related
to
scientific
and
ethical
aspects
of
human
subjects
research.
This
report
has
not
been
reviewed
for
approval
by
the
Agency
and,
hence,
the
contents
of
this
report
do
not
necessarily
represent
the
view
and
policies
of
the
Environmental
Protection
Agency,
nor
of
other
agencies
in
the
Executive
Branch
of
the
Federal
government,
nor
does
mention
of
trade
names
or
commercial
product
constitute
a
recommendation
for
use.
Further
information
about
the
EPA
Human
Studies
Review
Board
can
be
obtained
from
its
website
at
http://
www.
epa.
gov/
osa/
hsrb/.
Interested
persons
are
invited
to
contact
Paul
Lewis,
Designated
Federal
Officer,
via
e­
mail
at
lewis.
paul@
epa.
gov.

In
preparing
this
document,
the
Board
carefully
considered
all
information
provided
and
presented
by
the
Agency
presenters,
as
well
as
information
presented
by
public
commenters.
This
document
addresses
the
information
provided
and
presented
within
the
structure
of
the
charge
by
the
Agency.
8
of
69
United
States
Environmental
Protection
Agency
Human
Studies
Review
Board
Chair
Celia
B.
Fisher,
Ph.
D.
Marie
Ward
Doty
Professor
of
Psychology,
Director,
Center
for
Ethics
Education,
Fordham
University,
Department
of
Psychology,
Bronx,
NY
Vice
Chair
William
S.
Brimijoin,
Ph.
D.,
Chair
and
Professor,
Molecular
Pharmacology
and
Experimental
Therapeutics,
Mayo
Foundation,
Rochester,
MN
Members
David
C.
Bellinger,
Ph.
D.,
Professor
of
Neurology,
Harvard
Medical
School
Professor
in
the
Department
of
Environmental
Health,
Harvard
School
of
Public
Health
Children's
Hospital,
Boston,
MA
Alicia
Carriquiry,
Ph.
D.,
Professor,
Department
of
Statistics,
Iowa
State
University
Snedecor
Hall,
Ames,
IA
*

Gary
L.
Chadwick,
PharmD,
MPH,
CIP,
Associate
Provost,
Director,
Office
for
Human
Subjects
Protection,
University
of
Rochester,
Rochester,
NY
Janice
Chambers,
Ph.
D.,
D.
A.
B.
T.,
William
L.
Giles
Distinguished
Professor,
Director,
Center
for
Environmental
Health
Sciences,
College
of
Veterinary
Medicine,
Mississippi
State
University,
Wise
Center,
Mississippi
State,
MS
Richard
Fenske,
Ph.
D.,
MPH,
Professor,
Department
of
Environmental
and
Occupational
Health
Sciences,
University
of
Washington,
Seattle
WA
Susan
S.
Fish,
PharmD,
MPH,
Professor,
Biostatistics
&
Epidemiology,
Boston
University
School
of
Public
Health,
Co­
Director,
MA
in
Clinical
Investigation
Boston
University
School
of
Medicine,
Boston,
MA
Suzanne
C.
Fitzpatrick,
Ph.
D.,
DABT,
Senior
Science
Policy
Analyst,
Office
of
the
Commissioner,
Office
of
Science
and
Health
Coordination,
U.
S.
Food
and
Drug
Administration,
Rockville,
MD
Kannan
Krishnan,
Ph.
D.,
Professor,
Département
de
santé
environnementale
et
santé
au
travail,
Faculté
de
medicine,
Université
de
Montréal,
Montréal,
Canada
KyungMann
Kim,
Ph.
D.,
CCRP,
Professor
&
Associate
Chair,
Department
of
Biostatistics
&
Medical
Informatics,
School
of
Medicine
and
Public
Health,
University
of
Wisconsin­
Madison,
Madison,
WI
9
of
69
Michael
D.
Lebowitz,
Ph.
D.,
FCCP,
Professor
of
Public
Health
&
Medicine.
University
of
Arizona,
Tucson,
AZ
Lois
D.
Lehman­
Mckeeman,
Ph.
D.,
Distinguished
Research
Fellow,
Discovery
Toxicology,
Bristol­
Myers
Squibb
Company,
Princeton,
NJ
Jerry
A.
Menikoff,
M.
D.,
Associate
Professor
of
Law,
Ethics
&
Medicine,
Director
of
the
Institute
for
Bioethics,
Law
and
Public
Policy,
University
of
Kansas
Medical
Center,
Kansas
City,
KS
Robert
Nelson,
M.
D.,
Ph.
D.,
Associate
Professor
of
Anesthesiology
and
Critical
Care,
Department
of
Anesthesiology
and
Critical
Care,
University
of
Pennsylvania
School
of
Medicine,
The
Children's
Hospital
of
Philadelphia,
Philadelphia,
PA
19104
Sean
M.
Philpott,
Ph.
D.,
Research
Scientist,
David
Axelrod
Institute,
Wadsworth
Center
for
Laboratories
and
Research,
New
York
State
Department
of
Health,
Albany,
NY
Human
Studies
Review
Board
Staff
Paul
I.
Lewis,
Ph.
D.,
Designated
Federal
Officer,
United
States
Environmental
Protection
Agency,
Washington,
DC
*
Not
in
attendance
at
April
4­
6,
2006
Public
Meeting
10
of
69
TABLE
OF
CONTENTS
INTRODUCTION..............................................................................................................................................
11
REVIEW
PROCESS..........................................................................................................................................
12
CHARGE
TO
THE
BOARD
AND
BOARD
RESPONSE.................................................................................
13
1.
ALDICARB....................................................................................................................................................
13
2.
METHOMYL
.................................................................................................................................................
19
3.
OXAMYL
......................................................................................................................................................
25
4.
AZINPHOS­
METHYL......................................................................................................................................
32
5.
DDVP.........................................................................................................................................................
38
6.
ETHEPHON
...................................................................................................................................................
47
7.
HYDROGEN
CYANIDE...................................................................................................................................
54
8.
AMITRAZ......................................................................................................................................................
58
11
of
69
INTRODUCTION
On
February
6,
2006
(
71
Federal
Register
6137),
EPA
published
its
final
rule
for
protection
of
subjects
in
human
research.
This
new
rule
included
creating
an
independent
Human
Studies
Review
Board
(
HSRB)
to
provide
advice,
information
and
recommendations
related
to
the
scientific
and
ethical
issues
of
such
research.

The
Food
Quality
Protection
Act
(
1996)
mandated
that
the
Agency
reassess
pesticide
tolerances
(
i.
e.,
the
legal
limit
of
pesticides
in
food)
by
August,
2006.
The
Agency
is
in
the
final
stages
of
reassessing
all
tolerances
and
has
elected
for
the
inaugural
April
4­
6,
2006
HSRB
meeting
to
focus
on
those
pesticides
which
are
subject
to
the
August,
2006
statutory
deadline
for
tolerance
reassessment
and
which
have
a
human
toxicity
study
being
considered
for
incorporation
in
quantitative
human
health
risk
assessment.
The
HSRB
reviewed
toxicity
studies
involving
intentional
exposure
of
human
subjects
to
eight
pesticide
active
ingredients:
aldicarb,
amitraz,
azinphos­
methyl
(
AZM),
ethephon,
dichlorvos
(
DDVP),
methomyl,
oxamyl,
and
sodium
cyanide.
Three
of
these
pesticides
are
members
of
the
N­
methyl
carbamate
(
NMC)
common
mechanism
group
(
aldicarb,
methomyl,
oxamyl);
two
are
members
of
the
organophosphorus
pesticides
(
OP)
common
mechanism
group
(
AZM,
DDVP).
The
three
remaining
pesticides
(
amitraz,
ethephon,
sodium
cyanide)
each
have
toxicity
profiles
that
differ
from
the
other
chemicals.

The
Agency
prepared
a
variety
of
documents
which
provided
background
information.
These
included
the
proposed
and
final
Human
Studies
Rule,
report
from
the
National
Academy
of
Sciences
regarding
human
studies,
EPA,
Office
of
Pesticide
Programs'
(
OPP's)
policy
regarding
the
use
of
cholinesterase
data
in
human
health
risk
assessments,
and
a
slide
presentation
providing
a
broad
overview
of
the
OPP's
human
health
risk
assessments.
The
Agency
used
the
framework
provided
in
Emanuel
(
2000)
as
the
basis
for
its
ethics
reviews.
The
Agency
described
the
approach
for
performing
scientific
review
of
human
studies
and
for
incorporating
human
toxicity
data
into
risk
assessment.

For
each
of
the
human
studies
under
consideration,
the
Agency
provided
the
complete
study
report
as
submitted
to
the
Agency.
For
each
chemical,
the
Agency
developed
a
review
of
the
ethical
conduct
of
the
study.
Each
ethics
review
identified
any
deficiencies
noted
in
the
conduct
of
the
specific
study
compared
to
both
current
ethical
standards
and
the
ethical
standards
prevailing
at
the
time
the
research
was
performed.
The
Agency
intentionally
deferred
making
a
final
determination
of
whether
an
individual
study
satisfied
the
ethical
standards
for
acceptability
in
40
CFR
sections
26.1704
 
26.1706,
pending
the
advice
of
the
Board.

For
most
studies,
the
Agency
develops
documents,
called
Data
Evaluation
Records
(
DERs),
containing
a
scientific
review
of
the
study.
DERs
contain
summaries
of
the
study
design,
methods
and
results,
describe
potential
deficiencies,
and
provide
conclusions
about
the
usefulness
of
the
study
in
risk
assessment.
In
addition
to
the
DERs,
the
Agency
prepared
for
each
chemical
a
"
Weight
of
Evidence"
(
WOE)
memorandum
that
discusses
the
differences
and
similarities
between
the
human
and
animal
toxic
responses
to
each
chemical
and
characterizes
the
usefulness
of
the
human
toxicity
studies
for
human
health
risk
assessment.
The
WOE
memos
12
of
69
express
the
Agency's
most
current
scientific
conclusions
on
which
the
Agency
solicited
comments
from
the
Board.

The
HSRB
reviewed
both
studies
on
which
the
Agency
proposes
to
rely
on
actions
under
the
pesticide
laws
and
studies
that
the
Agency
has
decided
not
to
use
in
its
risk
assessments,
either
for
scientific
reasons
or
because
they
do
not
meet
the
standards
in
EPA's
final
human
studies
rule.
The
Agency
asked
the
HSRB
to
advise
the
Agency
on
a
range
of
scientific
and
ethics
issues
regarding
how
the
studies
should
be
assessed
against
the
provisions
in
40
CFR
sections
26.1701
 
26.1704
of
EPA's
final
human
studies
rule.
The
Board
anticipates
having
a
series
of
meetings
to
review
pesticide
human
studies
relevant
to
pending
re­
registration,
tolerance
reassessment
and
new
registration
decisions,
in
accordance
with
the
provisions
of
the
final
rule.
This
report
transmits
the
HSRB's
comments
and
recommendations
from
its
inaugural
April
4­
6,
2006
meeting.

REVIEW
PROCESS
On
April
4­
6,
2006
the
Board
had
a
public
face­
to­
face
meeting
in
Arlington,
Virginia.
Advance
notice
of
the
meeting
was
published
in
the
Federal
Register
"
Human
Studies
Review
Board:
Notice
of
Public
Meeting
and
Proposed
Candidates
for
Membership
to
the
Board
(
71
FR
46,
12194).
At
the
public
meeting,
following
welcoming
remarks
from
Agency
officials,
Celia
B.
Fisher,
HRSB
Chair,
proposed
a
set
of
scientific
and
ethics
criteria
consistent
with
the
language
of
71
Federal
Register
24,
6137
to
guide
Board
evaluation
of
each
protocol.
The
Chair's
scientific
criteria
asked
the
Board
to
consider
the
following
two
questions:
(
1)
Did
the
research
design
and
implementation
meet
scientific
standards
and
(
2)
Did
the
data
generated
by
the
protocol
have
implications
for
the
Agency's
Weight
of
the
Evidence
(
WOE)
review
and
when
applicable
aspects
of
the
risk
assessment?
The
Chair's
ethics
criteria
asked
the
Board
to
consider
three
questions:
(
1)
Did
the
study
fail
to
fully
meet
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted;
(
2)
Was
the
conduct
of
the
study
fundamentally
unethical
(
i.
e.,
specifically
was
there
clear
and
convincing
evidence
that
the
research
was
intended
to
seriously
harm
participants
or
failed
to
obtain
informed
consent);
and
(
3)
Was
the
conduct
of
the
study
significantly
deficient
relative
to
the
ethical
standards
prevailing
at
the
time
(
i.
e.,
was
there
clear
and
convincing
evidence
that
identified
deficiencies
could
have
resulted
in
serious
harm
based
on
knowledge
available
at
the
time
the
study
was
conducted
or
the
information
provided
to
participants
could
seriously
impair
informed
consent).
The
Board
then
heard
presentations
from
EPA
on
the
following
topics:
(
1)
introduction
(
summary
of
EPA
protections
for
subjects
of
human
research,
science
and
ethics
considerations
of
human
subjects
research);
(
2)
carbamate
pesticides
(
science
and
ethics
of
aldicarb,
methomyl
and
oxamyl
human
studies);
(
3)
organophosphate
pesticides
(
science
and
ethics
of
azinphos
methyl
and
DDVP
human
studies);
(
4)
other
pesticides
(
science
and
ethics
of
ethephon,
sodium
cyanide
and
amitraz
human
studies).
The
Board
also
heard
oral
public
comments
from
the
following
individuals:

Carbamate
pesticides
Mr.
Angus
Cameron
representing
BCG
Europe
Neil
Carmichael,
Ph.
D.
representing
Bayer
Crop
Science
Jennifer
Sass,
Ph.
D.
representing
Natural
Resources
Defense
Council
13
of
69
Organophosphate
Pesticides
Monty
Eberhart,
Ph.
D.
and
Mr.
Dan
Van
Geothen
representing
Bayer
Crop
Science
and
Mahktesheim
Agan
Robert
Levine,
Ph.
D.
representing
Amvac
Mr.
Ian
Chart
representing
Amvac
Laura
Plunkett,
Ph.
D.
representing
Amvac
Thomas
Starr,
Ph.
D.
representing
Amvac
Jennifer
Sass,
Ph.
D.
representing
Natural
Resources
Defense
Council
Ms.
Shelley
Davis
representing
the
Farmworker
Justice
Fund
Other
Pesticides
Neil
Carmichael,
Ph.
D.
representing
Bayer
Crop
Science
Following
Agency
presentations
and
public
comments,
the
Board
deliberated
on
the
charge
questions.
For
their
deliberations,
the
Board
considered
the
materials
presented
at
the
meeting,
written
public
comments
and
Agency
background
documents
on
each
individual
pesticide
(
i.
e.,
pesticide
human
study,
Agency
data
evaluation
record
(
DER)
of
the
pesticide
human
study,
weight
of
evidence
review,
risk
assessment
and
ethics
review).

CHARGE
TO
THE
BOARD
AND
BOARD
RESPONSE
1.
Aldicarb
Charge
to
the
Board
Aldicarb
is
a
N­
methyl
carbamate
(
NMC)
pesticide
whose
primary
toxic
effect
is
neurotoxicity
caused
by
the
inhibition
of
the
enzyme
acetylcholinesterase,
via
carbamylation
followed
by
rapid
recovery.
Aldicarb
can,
at
sufficiently
high
doses,
lead
to
a
variety
of
clinical
signs.
The
Agency
is
conducting
an
acute,
aggregate
(
single
chemical,
multi­
route)
risk
assessment
of
aldicarb.
In
addition,
aldicarb
is
a
member
of
the
N­
methyl
carbamate
common
mechanism
group
and
is
thus
included
in
the
cumulative
(
multi­
chemical,
multi­
route)
risk
assessment
for
the
NMCs.

1.1
Scientific
considerations
The
Agency's
"
Weight
of
the
Evidence"
(
WOE)
document
and
Data
Evaluation
Records
(
DERs)
for
aldicarb
described
the
study
design
and
results
of
the
aldicarb
acute
oral,
human
toxicity
study.
The
WOE
document
also
discussed
the
Agency's
conclusions
regarding
the
usefulness
of
the
human
study
in
the
acute,
aggregate,
single
chemical
risk
assessment
and
in
the
cumulative
risk
assessment
for
the
NMCs.
Regarding
the
aldicarb
human
study,
the
Agency
concluded
that
the
study
was
sufficiently
robust
for
reducing
the
inter­
species
(
i.
e.,
animal
to
human)
uncertainty
factor
in
the
aggregate
and
the
cumulative
risk
assessments.
14
of
69
The
Board
was
asked
to
comment
on
the
scientific
evidence
that
supports
whether
the
aldicarb
human
study
was
sufficiently
robust
for
reducing
the
inter­
species
(
i.
e.,
animal
to
human)
uncertainty
factor
in:
a.
single
chemical,
aggregate
risk
assessment
and
b.
cumulative
risk
assessment.

Board
Response
to
the
Charge
Brief
Overview
of
the
Study
The
study
(
Wyld
et
al.
1992)
consisted
of
a
double
blind,
placebo­
controlled,
single
oral
dose
of
aldicarb
in
orange
juice,
taken
during
the
course
of
a
meal.
A
variety
of
both
subjective
and
objective
observations
were
accumulated,
including
red
blood
cell
(
RBC)
cholinesterase
activities,
blood
pressure,
and
respiratory
parameters
among
others.
Several
dose
levels
were
investigated
and
several
time
points
were
also
investigated.

Critique
of
Study
The
strengths
of
the
study
were:
it
was
designed
with
multiple
doses
so
a
dose­
response
relationship
could
be
studied;
it
was
double
blind;
a
large
number
of
parameters
that
are
relevant
to
anticholinesterase
were
studied
(
including
both
subjective
data
such
as
headache
and
1several
objective
physiological
measures
such
as
blood
pressure,
pulse,
pulmonary
function
and
saliva
production);
there
were
exclusion
criteria;
there
were
frequent
measurements
of
cholinesterase
over
a
1
day
period
in
addition
to
pre­
treatment
measurements;
the
observations
of
clinical
signs
were
made
by
trained
observers;
both
sexes
were
studied
(
although
there
were
fewer
doses
and
individuals
in
the
female
group);
and
the
cholinesterase
depression
was
both
dose­
and
timedependent
in
both
males
and
females.

The
weaknesses
of
the
study
were:
there
were
typically
only
4­
8
individuals
per
dose;
there
were
fewer
female
subjects
and
they
were
only
tested
at
the
middle
dose
levels;
there
were
a
large
number
of
reported
signs
across
all
groups,
including
the
placebo,
making
interpretation
difficult;
the
cholinesterase
methodology
may
have
not
assayed
all
of
the
cholinesterase
in
RBCs;
and
the
first
time
point
of
cholinesterase
measurement
may
have
been
after
the
time
of
peak
cholinesterase
inhibition.

The
Board
also
noted
that,
with
respect
to
statistical
analysis,
the
study
was
likely
to
be
under­
powered.
With
the
large
number
of
endpoints
and
the
relatively
large
between­
subject
variances
in
almost
all
endpoints,
the
number
of
subjects
was
probably
insufficient
to
guarantee
adequate
statistical
power.
In
addition,
no
adjustments
were
made
for
multiple
comparisons.
Since
each
endpoint
was
analyzed
separately
and
because
many
comparisons
were
carried
out
across
genders,
time
points,
doses,
etc.,
the
overall
confidence
level
is
probably
much
below
the
nominal
95%.
It
was
also
noted
that
the
univariate
statistical
models
that
were
fitted
to
the
data
account
for
the
repeated
measures
structure
of
the
design,
but
do
not
account
for
the
multivariate
structure
in
the
measurements.
Because
endpoints
were
measured
on
the
same
subjects,
one
could
expect
meaningful
correlations
between
the
various
endpoints
that
could
contain
additional
information
about
the
treatment
effects
and
the
effects
of
covariates.
Consequences
of
not
using
15
of
69
multivariate
methods
on
this
data
set
include
a
decrease
in
the
power
of
statistical
tests
and
erosion
of
confidence
levels
that
occur
when
many
models
are
fitted
to
many
endpoints
independently
as
was
done
in
this
study.
These
considerations
throw
some
doubt
on
some
of
the
study
results
that
suggest
no
statistically
significant
treatment
effects.

Nevertheless,
while
it
is
clear
that
the
statistical
power
of
the
study
was
low,
the
data
do
show
a
very
clear
and
predictable
dose­
and
time­
dependency
in
the
RBC
cholinesterase
data.
The
response
of
the
cholinesterase
data
is
what
would
be
expected
of
a
transient
carbamate
anticholinesterase.
Additionally,
it
would
be
expected
that
blood
cholinesterase
would
be
the
most
sensitive
endpoint.
RBC
cholinesterase
is
well
recognized
as
a
sensitive
biomarker
of
exposure
to
anticholinesterases.
Its
inhibition
is
not
responsible
for
clinical
signs
of
anticholinesterase
toxicity,
so
no
cause­
and­
effect
relationship
should
be
expected
between
RBC
cholinesterase
inhibition
and
changes
in
any
of
the
physiological
parameters
measured.
Therefore,
it
is
also
reasonable
that
inhibition
of
the
RBC
cholinesterase
would
occur
whereas
the
other
parameters
related
to
clinical
signs,
such
as
salivation
or
blood
pressure,
would
not.
Lastly,
the
occurrence
of
numerous
clinical
signs
in
the
placebo
group
gives
credence
to
the
conclusion
that
the
RBC
cholinesterase
inhibition
was
a
treatment­
related
effect
whereas
clinical
signs
were
not.

The
Board
concluded
that
the
results
of
the
study
could
be
used
in
the
WOE
analysis
to
determine
a
NOEL
for
RBC
cholinesterase
and
clinical
signs
in
males
and
that
the
RBC
cholinesterase
demonstrated
a
dose­
dependent
and
time­
dependent
pattern
of
inhibition
in
both
males
and
females.

HSRB
Consensus
and
Rationale
The
Board
concluded
that
the
cholinesterase
data
from
the
aldicarb
human
study
were
reliable
for
use
in
the
aldicarb
single
chemical,
aggregate
risk
assessment.

The
Agency
Data
Evaluation
Report
for
Aldicarb
(
Sette
1992)
suggested
that
the
NOAEL
and
LOAEL
were
based
upon
sweating
in
males.
While
sweating
is
a
possible
clinical
sign
resulting
from
cholinesterase
inhibition,
the
responses
in
the
subjects
were
not
consistently
doserelated
Although
sweating
is
an
objective
endpoint,
the
WOE
document
indicates
that
the
RBC
cholinesterase
inhibition
would
be
the
more
appropriate
objective
endpoint.
There
are
additional
reasons
why
there
is
more
confidence
in
the
cholinesterase
data.
First,
the
blood
cholinesterase
data,
despite
their
weaknesses,
are
the
most
consistent
responses
to
aldicarb
exposure,
because
they
follow
time­
and
dose­
dependent
patterns,
as
would
be
expected
of
a
transient
anticholinesterase.
Second,
the
cholinesterase
data,
though
probably
based
on
incomplete
fractions
of
the
entire
RBC
cholinesterase
population
due
to
the
nature
of
the
analysis
method,
would
still
be
expected
to
be
internally
consistent
within
this
study
between
samples
of
treated
and
placebo
individuals,
and
therefore
the
inhibition
levels
can
probably
be
believed.
There
was
a
dose­
and
time­
to­
recovery­
related
relationship
to
cholinesterase
inhibition
in
both
sexes,
so
the
cholinesterase
data
are
also
consistent
between
the
sexes.

The
Board
concluded
that
the
cholinesterase
data
from
the
aldicarb
human
toxicity
study
were
reliable
for
use
in
the
cumulative
risk
assessment
for
N­
methyl
carbamates.
Aldicarb,
16
of
69
being
an
N­
methyl
carbamate,
belongs
to
this
common
mechanism
group
which
acts
via
acetylcholinesterase
inhibition.
Therefore,
the
endpoint
in
the
cumulative
risk
assessment
must
be
cholinesterase
inhibition.
Moreover,
the
dose­
response
data
from
the
human
study
appeared
such
that
BMD
and
BMDL
can
be
calculated.
The
HSRB
concluded
that
the
aldicarb
human
study
appears
to
be
a
scientifically
valid
study,
suitable
for
use
in
both
the
aggregate
risk
assessment
and
the
cumulative
risk
assessment.

While
the
Board
concluded
that
the
cholinesterase
data
could
be
reliably
used
in
the
cumulative
risk
assessment,
it
did
note
some
limitations.
The
animal
data
were
not
supplied
so
the
HSRB
cannot
address
the
accuracy
of
the
corresponding
animal
data.
Because
of
the
rapid
reactivation
of
carbamylated
cholinesterase,
it
is
unclear
whether
accurate
cholinesterase
inhibition
values
were
obtained
in
the
human
study
or
that
peak
inhibition
was
measured
because
the
earliest
time
point
measured
was
1
hour
post­
dose.
The
WOE
document
stated
that
the
human
and
rat
cholinesterase
inhibition
were
comparable
at
the
0.05
mg/
kg
dose
level;
a
question
arises
as
to
whether
this
comparison
was
made
at
the
same
point
in
the
inhibition/
recovery
patterns
of
both
species.
However,
it
should
be
possible
to
make
extrapolations
of
the
possible
peak
from
animal
data
on
the
time
course
pattern
of
cholinesterase
inhibition
and
recovery,
and
the
Agency
is
urged
to
make
certain
that
BMD
and
BMDL
comparisons
between
animals
and
humans
are
being
made
on
comparable
times
in
the
inhibition/
recovery
pattern.

1.2.
Ethical
considerations
Charge
to
the
Board
a.
The
Agency
requests
that
the
Board
provide
comment
on
the
following:

In
light
of
the
ethics
committee's
instruction
that
the
lay
summary
be
"
greatly
expanded,"
and
the
fact
that
the
materials
used
to
obtain
informed
consent
listed
a
limited
range
of
symptoms
of
carbamate
toxicity
(
excluding
some
reported
as
adverse
effects
in
the
study),
included
multiple
references
to
the
test
material
as
a
drug,
and
failed
to
identify
dose
levels
to
be
administered
to
male
subjects,
whether,
the
materials
used
to
obtain
informed
consent
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted
Whether
the
absence
from
the
protocol
of
discussion
of
the
potential
risks
to
subjects
or
benefits
to
society
of
conducting
the
proposed
research
(
as
required
by
the
1989
Declaration
of
Helsinki,
Principle
#
4,
with
which
the
research
asserted
compliance)
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;

b.
The
Agency
asks
that
the
Board
provide
comment
on
the
following,
taking
into
account
all
that
is
known
about
the
ethical
conduct
of
this
study:

OPP's
conclusion
that
there
was
not
clear
and
convincing
evidence
that
the
conduct
of
the
research
was
fundamentally
unethical.
17
of
69
Whether
there
is
clear
and
convincing
evidence
that
the
conduct
of
the
study
was
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

Board
Response
to
the
Charge
Study
Overview
The
study
was
completed
on
March
11,
1992.
The
study
sponsor
was
located
in
France
and
the
performing
laboratory
was
located
in
Scotland.
The
protocol
documents
specifically
stated
that
the
research
was
conducted
in
compliance
with
the
Principles
of
Good
Clinical
Practice
as
promulgated
by
the
EMEA
CPMP
in
May
1990,
and
the
Declaration
of
Helsinki
(
in
either
the
1983
or
1989
version,
as
cited
in
two
different
portions
of
the
study
documents).
Although
the
May
1990
document
on
good
clinical
practice
was
the
precursor
for
the
subsequent
1997
document
promulgated
by
the
International
Conference
on
Harmonization,
the
earlier
document
did
not
include
any
specification
of
the
contents
of
the
informed
consent
form.
However,
the
supporting
and
supplementary
study
documents
claimed
that
the
research
ethics
committee
provided
independent
review
and
oversight
of
the
research
functioned
according
to
the
standards
of
the
FDA
regulations
found
in
21
CFR
56.
These
regulations
cross­
reference
the
informed
consent
requirements
found
in
21
CFR
50
Both
FDA
regulations
were
effective
on
January
27,
1981.
As
such,
the
research
ethics
committee
should
have
applied
the
FDA
regulations
from
nearly
a
decade
before
the
conduct
of
this
particular
research
protocol.
It
should
be
noted
that
the
sponsor
subsequently
claimed
that
the
study
also
was
performed
according
to
the
requirements
of
40
CFR
26,
based
on
a
retrospective
analysis
published
in
2003.

Critique
of
Study
The
Board
concurred
with
the
Agency
on
the
factual
observations
of
the
strengths
and
weaknesses
of
the
study,
as
detailed
in
Carley
(
2006a).
However,
further
comments
are
warranted
on
(
1)
the
documentation
and
process
of
informed
consent,
and
(
2)
the
minimization
of
risk
with
respect
to
the
study
design.

It
is
clear
that
the
written
documentation
for
informed
consent
is
not
up
to
the
standards
found
in
the
above
regulations.
The
Volunteer
Information
that
was
given
to
research
subjects
as
an
appendix
to
the
signed
informed
consent
document
did
not
have
an
adequate
discussion
of
the
risks
of
the
research.
At
the
request
of
the
research
ethics
committee
(
dated
December
24,
1991),
the
Volunteer
Information
included
the
possibility
that
administration
of
the
test
product
could
result
in
"
gut
motility
effects
(
abdominal
pains),
effect
on
eye
pupil
size
and
muscle
weakness").
In
addition
to
the
concerns
that
the
risk
information
was
insufficient
in
the
written
consent
documentation,
selected
subjects
were
enrolled
a
second
time.
This
was
not
discussed
or
in
the
protocol
or
the
informed
consent
documentation
and
therefore
raises
doubts
to
the
Board
about
the
adequacy
of
the
consent
process.
In
effect,
the
re­
dosing
of
selected
subjects
suggests
that
the
investigator
was
unblinded
to
group
assignment,
reducing
the
supposedly
double
blind
study
to
a
single­
blind
study
and
raising
doubts
(
unanswered
by
the
documentation)
about
the
sufficiency
of
informed
consent.
In
particular,
the
re­
use
of
selected
subjects
suggests
that
some
study
participants
were
randomized
to
receive
placebo
versus
active
compound
while
other
18
of
69
subjects
were
not.
As
a
result,
the
burden
of
risks
was
unlikely
to
have
been
distributed
evenly
among
all
study
participants.

There
were
several
observations
that
raised
concerns
about
the
extent
to
which
the
study
design
minimized
risk
to
research
subjects.
First,
the
dosing
schedule
did
not
adhere
to
a
strict
dose
escalation
design.
As
a
result,
it
is
possible
that
subjects
dosed
at
higher
levels
would
experience
significant
adverse
events
that
could
have
been
anticipated
in
a
more
traditional
dose
escalation
design.
The
Board
recognized
that
the
public
comments
by
Bayer
CropScience
presented
during
the
public
comment
period
at
the
HSRB
meeting
suggested
that
there
was
previous
human
testing
data
available
to
indicate
that
such
risks
would
be
unlikely.
Second,
the
stopping
rule
based
on
a
70%
inhibition
of
cholinesterase
activity
is
fairly
liberal
(
i.
e.
not
protective),
given
that
70%
inhibition
would
likely
result
in
significant
adverse
effects.
Although
no
subject
in
the
research
actually
experienced
this
level
of
cholinesterase
reduction,
the
selection
of
such
a
stopping
rule
increases
the
risk
to
subjects.
Finally,
the
letter
to
the
subjects'
general
practitioner
does
not
contain
any
information
about
the
actual
study
and
the
product
being
administered
other
than
the
name
of
the
compound.
As
such,
this
minimizes
the
extent
to
which
the
opinion
of
the
general
practitioner
could
protect
the
research
subject.

HSRB
Consensus
and
Rationale
The
Board
concluded
that:

a)
The
aldicarb
human
toxicity
study
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted.

b)
There
was
no
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained.

c)
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted),
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

Informed
Consent:
While
informed
consent
was
obtained,
the
informed
consent
documents
did
not
include
adequate
discussion
of
the
research
risks
as
documented
by
Carley
(
2006a)
and
did
not
fully
meet
ethical
standards
prevalent
at
the
time
the
study
was
conducted.
There
was
a
suggestion
that
additional
aspects
of
risk
may
have
been
discussed
in
the
Volunteer
Information.
Although
the
Board
recognized
that
the
documentation
would
not
meet
today's
standards,
the
lack
of
documentation
does
not
in
and
of
itself
demonstrate
a
significant
deficiency
that
would
have
seriously
impaired
the
participants'
ability
to
provide
informed
consent.

Participant
risk:
The
Board
concurred
that
the
stopping
rule
based
on
70%
reduction
in
cholinesterase
activity
raised
the
possibility
of
exposing
subjects
to
inappropriate
risk.
However,
the
Board
acknowledged
that
data
existed
at
the
time
to
suggest
that
the
doses
used
in
the
study
19
of
69
would
likely
not
achieve
this
level.
Thus,
there
was
no
evidence
that
serious
harm
was
intended
nor
that
serious
harm
could
have
resulted
from
the
implementation
of
the
study.

The
Board
concluded
that
there
was
no
obvious
reason
why
the
Agency
cannot
rely
on
the
results
of
this
study,
as
appropriate
under
current
pesticide
laws,
given
the
absence
of
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical
or
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

2.
Methomyl
Charge
to
the
Board
Methomyl
is
a
member
of
the
N­
methyl
carbamate
(
NMC)
common
mechanism
group
based
on
its
ability
to
inhibit
acetylcholinesterase
via
carbamylation.
The
Agency
had
previously
completed
the
acute,
aggregate
(
single
chemical,
multi­
route)
risk
assessment
of
methomyl.
At
the
present
time,
the
Agency
is
considering
the
use
of
the
methomyl
acute
oral,
human
toxicity
study
to
inform
the
inter­
species
uncertainty
factor
used
in
the
cumulative
risk
assessment
of
the
NMCs.

Scientific
considerations
The
Agency's
WOE
document
and
DER
for
methomyl
describe
the
study
design
and
results
of
the
methomyl
acute
oral
human
study.
The
WOE
document
also
discusses
the
Agency's
conclusions
regarding
the
usefulness
of
the
human
study
in
the
cumulative
risk
assessment
for
the
NMCs.
For
methomyl,
the
Agency
had
concluded
that
the
human
toxicity
study
supports
a
10X
inter­
species
uncertainty
factor
for
methomyl
in
the
cumulative
risk
assessment
of
the
NMCs.

Please
comment
on
the
scientific
evidence
that
supports
this
conclusion.

Board
Response
to
the
Charge
Study
Overview
A
study
with
methomyl
was
conducted
in
human
subjects
using
a
double­
blind,
placebocontrolled
single
ascending
dose
design
(
McFarlane
et
al.
1998).
The
defined
goal
of
the
study
was
to
determine
an
acute
no­
adverse
effect
level
(
NOAEL)
based
on
inhibition
of
plasma
and
RBC
cholinesterase,
and
in
the
original
protocol,
the
doses
were
projected
to
be
0.1,
0.3,
0.5,
0.75,
1
and
1.5
mg/
kg.
Methomyl
was
administered
as
a
bolus
dose
in
a
capsule
immediately
(
about
5
minutes)
following
a
meal,
and
post­
dose
blood
sampling
commenced
at
15
minutes
after
dosing.
Collection
of
blood
samples
for
analysis
of
plasma
and
RBC
acetylcholinesterase
activity
was
continued
for
24
hours
after
dosing.
Plasma
and
RBC
acetylcholinesterase
activities
were
compared
to
a
baseline
measurement,
determined
from
two
predose
samples
collected
16
hours
and
30
minutes
prior
to
dosing,
for
each
subject.
The
results
were
compared
to
the
placebo
group.
In
addition,
numerous
physiological
parameters
including
ECG,
heart
rate,
pulse,
blood
pressure,
body
temperature,
clinical
chemistry
and
hematology
parameters,
determination
of
20
of
69
pupil
size
and
salivation
were
assessed
during
the
entire
24
hour
period
after
dosing.
The
criterion
for
not
escalating
to
the
next
dose
was
inhibition
of
RBC
cholinesterase
exceeding
40%.

Critique
of
Study
The
scientific
validity
of
this
study
was
determined
by
its
comparative
strengths
and
weaknesses.
The
strengths
of
this
study
were
determined
by
the
comprehensive
analysis
of
cholinesterase
inhibition
that
was
obtained
including:

 
The
design
and
results
established
a
clear
dose­
response
and
time­
dependent
relationship
for
inhibition
of
RBC
cholinesterase.
This
was
based
on
the
execution
of
three
dose
levels
in
the
ascending
dose
paradigm.
The
dosages
evaluated
were
0.1,
0.2
and
0.3
mg/
kg.
 
The
analysis
of
the
temporal
pattern
of
RBC
cholinesterase
inhibition
was
comprehensive
and
complete.
Specifically,
blood
samples
were
collected
at
15
minutes
after
dosing,
with
15
minute
sampling
intervals
for
the
first
2
hours,
followed
by
sample
collection
for
evaluation
at
2,
3,
4,
6,
8,
12
and
24
hours
after
dosing.
This
time
course
established
the
peak
of
cholinesterase
inhibition
and
assured
recovery
of
enzyme
activity
in
all
subjects.
 
The
inclusion
of
clinical
endpoints
associated
with
increased
cholinergic
stimulation
as
additional
endpoints
provided
additional
relevant
measures
of
potential
adverse
effects
during
the
course
of
the
24
hour
study.

Several
weaknesses
of
the
study
were
noted,
and
these
weaknesses
are
also
based
on
aspects
relating
to
its
design
and
conduct
and
include:

 
All
subjects
were
male,
with
no
data
obtained
from
females
 
The
group
size
(
5/
dose
level)
was
small
 
The
establishment
of
the
baseline
RBC
cholinesterase
level
from
which
all
subjects
were
compared
was
the
mean
of
2
determinations,
which,
given
the
general
pattern
of
variation,
reduces
the
confidence
in
the
calculation
of
percent
inhibition
of
the
enzyme.

One
additional
issue
concerning
the
design
and
execution
of
this
study
was
the
initial
proposed
dose
escalation
which
ranged
from
0.1
to
1.5
mg/
kg
(
0.1,
0.3,
0.5,
0.75,
1,
and
1.5
mg/
kg)
and
the
criterion
not
to
escalate
the
dose
when
inhibition
of
RBC
cholinesterase
exceeded
40%.
There
was
one
instance
in
which
this
criterion
was
not
adhered
to.
In
the
first
session
of
the
study,
one
subject
was
dosed
with
placebo
and
the
other
received
methomyl
at
0.1
mg/
kg.
The
subject
receiving
methomyl
showed
evidence
of
RBC
cholinesterase
inhibition
exceeding
40%
(
approximately
43%),
but
this
change
was
determined
at
8
hours
after
dosing.
The
study
author
concluded
that,
based
on
the
general
knowledge
and
understanding
of
the
rapidity
of
enzyme
inhibition
observed
with
the
carbamates,
this
finding
was
likely
to
be
a
spurious
result.
In
review
of
the
data
for
RBC
cholinesterase
inhibition
for
this
session,
it
was
also
noted
that
the
placebo­
treated
subject
in
this
session
showed
a
20%
decrease
in
baseline
enzyme
activity,
thereby
suggesting
a
possible,
albeit
unconfirmed,
issue
regarding
the
accuracy
and
reliability
of
the
analysis
of
enzyme
activity
in
these
samples.
Therefore,
the
sponsor's
conclusion
that
the
effect
observed
in
the
subject
dosed
with
0.1
mg/
kg
methomyl
was
most
likely
to
be
a
spurious
21
of
69
result
was
considered
scientifically
reasonable
and
justifiable,
and
the
decision
to
escalate
the
dose
in
the
next
session
was
not
in
violation
of
the
protocol.

In
the
second
session
of
the
study,
the
lead
subject
dosed
with
methomyl
at
0.3
mg/
kg
also
showed
a
greater
than
40%
inhibition
of
RBC
cholinesterase.
Consequently,
the
next
session
completed
the
five
subjects
to
be
used
in
this
group
but
did
not
escalate
the
dose
further
as
per
the
study
protocol.
Therefore,
the
highest
dosage
evaluated
in
the
study
was
0.3
mg/
kg,
which
was
much
lower
than
the
original
intended
escalation
up
to
1.5
mg/
kg.
To
establish
a
better
dose­
response
relationship,
the
study
was
unblinded,
and
a
dosage
of
0.2
mg/
kg
was
added
to
the
protocol
after
which
the
study
was
re­
blinded
and
completed.

HSRB
Consensus
and
Rationale
The
Board
concluded
that
the
methomyl
human
study
could
be
appropriately
applied
to
the
inter­
species
risk
factor
for
methomyl
and
for
use
in
the
cumulative
risk
assessment
of
N­
methyl
carbamates.

The
HSRB
concluded
that
data
from
the
study
in
human
subjects
exposed
to
methomyl
provided
a
meaningful
assessment
of
the
dose­
response
relationship
and
time
course
for
inhibition
of
RBC
cholinesterase
in
human
subjects.
The
strengths
of
the
study
design
and
conduct
outweigh
the
indicated
weaknesses,
and
the
results
are
scientifically
valid.
Therefore,
the
data
can
be
used
to
inform
the
assessment
of
interspecies
uncertainty
factors
for
methomyl.

Ethical
considerations
Charge
to
the
Board
2.2.1.
The
Agency
requested
that
the
Board
provide
comment
on
the
following:

 
Whether
the
investigators'
decision
to
administer
a
dose
to
additional
subjects
in
session
3,
when
one
subject
receiving
that
dose
in
session
2
displayed
RBC
ChEI
greater
than
40%,
a
response
that
triggered
the
protocol's
anti­
escalation
provision,
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;

 
Whether
the
timing
of
the
investigators'
report
to
the
ethics
committee
of
the
adverse
effects
observed
in
one
subject
during
session
2
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;

 
Whether
the
failure
of
the
investigators
to
request
approval
from
the
ethics
committee
for
certain
amendments
to
the
approved
protocol,
as
required
by
the
protocol,
when
the
changes
were
administrative
and
had
no
effect
on
the
safety
of
the
subjects
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;
and
22
of
69
 
Whether
the
absence
from
the
protocol
of
discussion
of
the
potential
risks
to
subjects
or
benefits
to
society
of
conducting
the
proposed
research
(
as
required
by
the
Declaration
of
Helsinki,
Principle
#
5)
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;
and
2.2.2.
The
Agency
asked
that
the
Board
provide
comment
on
the
following,
taking
into
account
all
that
is
known
about
the
ethical
conduct
of
this
study:

 
OPP's
conclusion
that
there
was
no
clear
and
convincing
evidence
that
the
conduct
of
the
research
was
fundamentally
unethical.

 
Whether
there
was
clear
and
convincing
evidence
that
the
conduct
of
the
study
was
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted,

Board
Response
to
the
Charge
Brief
Overview
of
the
Study
The
study
was
performed
by
a
commercial
research
organization,
Inveresk
Clinical
Research
of
Edinburgh,
Scotland
and
sponsored
by
the
Haskell
Laboratory
for
Toxicology
and
Industrial
Medicine,
E.
I.
du
Pont
de
Nemours
and
Company,
of
Newark,
Delaware.
The
protocol
documents
specifically
state
that
the
research
was
conducted
in
compliance
with
the
Principles
of
Good
Clinical
Practice
promulgated
by
the
International
Conference
on
Harmonization
(
CMPM/
ICH/
135/
95),
and
the
1996
version
of
the
Declaration
of
Helsinki.

Critique
of
Study
The
Board
concurred
with
the
Agency's
factual
observations
of
the
strengths
and
weaknesses
of
the
study,
as
detailed
in
Carley
(
2006b).
However,
further
comments
are
warranted
on
certain
events
that
took
place
during
the
conduct
of
the
study.

1.
Determination
That
Certain
Data
Were
Spurious
In
session
one
of
the
study,
one
of
the
subjects
exhibited
a
greater
than
40%
inhibition
in
RBC
cholinesterase
activity
at
one
point,
without
any
signs
or
symptoms.
According
to
the
protocol,
such
inhibition
of
cholinesterase
was
a
criterion
for
not
escalating
to
the
next
dose
level.
Because
this
occurred
at
8
hours
post
dose,
study
personnel
considered
this
to
be
a
spurious
result
and
went
ahead
with
escalation
to
the
next
dose
without
consulting
with
the
ethics
review
board
(
It
is
somewhat
unclear
when
the
results
of
the
assay
became
available;
the
observation
about
this
result
is
described
as
being
noted
"
retrospectively
at
the
time
of
reporting,
when
there
was
no
sample
available
for
retesting.").
If
this
determination
of
spuriousness
had
been
incorrect,
then
giving
the
following
subject
an
escalated
dose
might
have
placed
that
subject
at
considerable
risk.
23
of
69
The
Board
concluded
that
the
determination
of
spuriousness
was
reasonable
at
the
time,
given
the
late
timing
of
the
change
in
cholinesterase
levels,
and
the
similar
change
observed
in
cholinesterase
levels
for
a
subject
in
session
one
who
received
placebo.
Nonetheless,
the
Board
determined
that
a
far
more
appropriate
action
would
have
been
for
the
researchers
to
have
first
consulted
with
the
ethics
review
committee
about
repeating
that
0.1
mg/
kg
dose
before
proceeding
with
dose
escalation.
Moreover,
the
report
of
the
study
results
stated
that
"
laboratory
tests
showing
abnormal
values
for
any
subject
were
repeated
as
often
as
deemed
necessary
by
the
clinical
investigator
until
the
test
values
returned
to
accepted
limits
or
until
an
explanation
other
than
compound
effect
was
given."
In
spite
of
this,
it
does
not
appear
that
any
additional
tests
were
performed;
study
participants
only
received
scheduled
laboratory
tests
at
the
12
hour
and
24
hour
points.
Although
there
was
a
possibility
that
these
events
might
have
placed
subjects
at
an
increased
risk
of
harm,
the
Board
determined
that
there
was
not
clear
and
convincing
evidence
that
this
could
have
resulted
in
serious
harm
to
subjects,
particularly
given
the
information
known
about
the
compound
being
tested
and
the
other
protections
in
place
as
part
of
the
protocol.

2.
Decision
to
Proceed
with
Third
Session
In
session
two
of
the
study,
one
subject
who
received
an
escalated
dose
of
0.3
mg/
kg
exhibited
a
greater
than
40%
inhibition
in
RBC
cholinesterase,
together
with
self­
reported
clinical
symptoms
(
i.
e.
headache).
As
noted
above,
the
protocol
indicated
that
dose
escalation
would
not
occur
if
any
subject
experienced
such
a
level
of
inhibition.
The
protocol
was
followed
in
this
regard:
additional
subjects
were
tested
at
the
0.3
mg/
kg
dose,
but
not
at
any
higher
doses.
However,
the
protocol
also
stated
that
the
study
would
stop
if
a
subject
both
had
greater
than
40%
inhibition
and
also
demonstrated
signs
or
symptoms
of
carbamate
toxicity
(
one
of
which
might
be
considered
to
be
a
headache).
Although
the
Board
was
concerned
that
this
decision
to
continue
the
study
and
to
test
additional
subjects
at
the
0.3
mg/
kg
dose
was
made
without
consulting
the
ethics
review
committee,
it
determined
that
the
provisions
of
the
protocol
were
sufficiently
unclear
as
applied
to
these
facts
(
particularly
regarding
what
constitute
signs
and
symptoms
of
toxicity);
the
actions
of
the
investigators
were
thus
consistent
with
the
protocol
as
written.
In
addition,
given
the
protections
that
were
in
place
as
part
of
the
protocol,
and
the
information
then
known
about
the
compound
being
studied,
the
Board
concluded
that
there
was
not
clear
and
convincing
evidence
that
this
decision
presented
a
risk
of
substantial
harm
to
the
subjects.
Nonetheless,
the
Board
concluded
that
a
more
appropriate
course
of
action
would
have
been
for
the
researchers
to
have
consulted
with
the
ethics
review
board
before
proceeding
with
the
study.
This
conclusion
and
the
desirability
of
having
taken
similar
actions
after
the
apparently
"
spurious"
result
in
session
one
is
underscored
by
public
comments
presented
to
the
Board
that
the
observation
of
acetylcholinesterase
depression
at
0.3
mg/
kg
was
"
surprising."
There
is
a
danger
in
explaining
away
unexpected
findings
based
on
prior
expectations,
and
ethics
review
boards
should
play
an
important
role
in
preventing
investigators
from
falling
prey
to
such
expectations.

3.
Amendment
of
the
Protocol
Following
the
testing
of
the
subjects
at
the
0.3
mg/
kg
level
as
part
of
session
three,
the
protocol
was
amended
to
allow
additional
subjects
to
be
tested
at
the
0.2
mg/
kg
level.
This
24
of
69
change
was
approved
by
the
chair
of
the
ethics
review
committee,
consistent
with
procedures
for
the
committee
which
allowed
the
chair
to
approve
amendments
that
did
not
increase
the
risk
level
(
i.
e.,
did
not
involve
testing
subjects
at
a
dose
level
above
those
approved
by
the
convened
board).
Although
the
Board
did
not
conclude
this
was
a
formal
violation
of
then­
existing
ethical
standards,
some
members
of
the
Board
were
concerned
that
the
ethics
committee
chair's
actions
were
inappropriate
and
that
the
protocol
change
should
have
been
reviewed
by
the
full
committee
because
additional
subjects
were
being
exposed
to
a
study
compound
beyond
those
contemplated
by
the
unamended
protocol.

HSRB
Consensus
and
Rationale
The
Board
concluded
that:

a.
The
methomyl
human
toxicity
study
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted,
however
b.
There
was
no
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained,
and.

c.
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted),
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

(
1)
The
Board
concluded
that
the
decision
to
administer
a
dose
to
additional
subjects
in
session
three
could
not
be
determined
to
be
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted
because,
as
discussed
above,
that
decision
could
be
interpreted
as
consistent
with
the
terms
of
the
protocol
and
was
not
likely
to
expose
the
subjects
to
additional
serious
harm.

(
2)
The
Board
concluded
that
the
timing
of
the
investigators'
report
to
the
ethics
committee
regarding
what
happened
to
the
subject
who
experienced
cholinesterase
inhibition
during
session
two
should
not
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted,
given
the
subject's
minimal
symptoms
and
the
fact
that
RBC
cholinesterase
inhibition
by
itself
is
not
considered
an
adverse
event.

(
3)
The
Board
determined
that
the
failure
of
the
investigators
to
request
approval
from
the
ethics
committee
for
certain
amendments
to
the
approved
protocol,
while
deficient
relative
to
the
ethical
standards
prevailing
at
the
time
the
study
was
conducted,
should
not
be
considered
significantly
deficient,
given
that
these
changes
were
purely
administrative.

(
4)
The
Board
determined
that
the
absence
from
the
protocol
of
discussion
of
the
potential
risks
to
subjects
or
benefits
to
society
of
conducting
the
proposed
research
(
as
required
by
the
Declaration
of
Helsinki,
Principle
#
5)
should
not
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.
The
potential
risks
and
25
of
69
benefits
are
described
in
the
research
subject
information
sheet/
informed
consent
document.
While
not
in
the
protocol
itself,
they
are
nonetheless
included
in
the
materials
provided
to
the
ethics
committee
(
and
to
the
potential
research
subject).
Thus,
the
ethics
committee
and
the
potential
research
subjects
had
the
opportunity
to
weigh
the
risks
and
benefits.

The
Board
concluded
that
there
was
no
obvious
reason
why
the
Agency
cannot
rely
on
the
results
of
this
study,
as
appropriate
under
current
pesticide
laws,
given
the
absence
of
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical
or
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

3.
Oxamyl
Charge
to
the
Board
Similar
to
aldicarb
and
methomyl,
oxamyl
is
a
member
of
the
N­
methyl
carbamate
(
NMC)
common
mechanism
group
based
on
its
ability
to
inhibit
acetylcholinesterase
via
carbamylation
and
is
thus
included
in
the
NMC
cumulative
risk
assessment.
The
Agency
had
previously
completed
the
acute,
aggregate
(
single
chemical,
multi­
route)
risk
assessment
of
oxamyl.
The
Agency
is
now
considering
the
use
of
the
oxamyl
acute
oral,
human
toxicity
study
to
inform
the
inter­
species
uncertainty
factor
in
the
cumulative
risk
assessment
of
the
NMCs.

3.1.
Scientific
considerations
The
Agency's
WOE
document
and
DER
for
oxamyl
described
the
study
design
and
results
of
the
oxamyl
acute
oral
human
toxicity
study.
The
WOE
document
also
discussed
the
Agency's
conclusions
regarding
the
usefulness
of
the
human
study
in
the
cumulative
risk
assessment
for
the
NMCs.
For
oxamyl,
the
Agency
had
concluded
that
the
human
toxicity
study
was
sufficiently
robust
for
reducing
the
10X
inter­
species
(
i.
e.,
animal
to
human)
uncertainty
factor
in
the
cumulative
risk
assessment.

Please
comment
on
the
scientific
evidence
that
supports
this
conclusion.

Board
Response
to
the
Charge
Study
Overview
The
stated
primary
objective
of
this
randomized,
double­
blind,
ascending
oral
dose
study
with
oxamyl
(
McFarlane
and
Freestone
1999a)
was
to
estimate
the
no­
observable­
adverse
effect
level
(
NOAEL)
for
oxamyl
in
humans
after
oral
administration.

The
study
used
40
healthy
male
subjects,
aged
19­
39.
Each
was
given
a
single
oral
dose
of
oxamyl
in
a
gelatin
capsule
at
doses
of
0
(
placebo),
0.005,
0.015,
0.03,
0.06,
0.09
or
0.15
mg/
kg
BW.
With
the
exception
of
dose
sessions
1
(
2
placebos),
2
(
1
placebo
and
1
at
0.005),
7
(
1
placebo
and
4
at
0.09),
8
(
1
placebo
and
1
0.15),
and
9
(
1
placebo
and
4
at
0.15),
all
other
dose
sessions
had
1
placebo,
4
at
current
dose,
and
1
at
the
next
higher
dose.
Plasma
and
RBC
cholinesterase
activity
were
assayed
at
screening
and
2
days,
16
hours
and
30
minutes
prior
to
26
of
69
dosing
and
at
0.25,
0.5,
0.75,
1.0,
1.25,
1.5,
1.75,
2,
3,
4,
6,
8,
12,
and
24
hours
post
dose
and
7
days
post
dose.
Other
clinical
parameters
indicative
of
carbamate
exposure,
such
as
urinalysis,
pupillometry,
saliva
increase
etc.
were
also
measured.

No
treatment
related
effects
for
ECG,
heart
rate,
pulse,
blood
pressure,
respiratory
rate,
body
temperature,
hematology,
clinical
chemistry,
urinalysis,
or
pupillometry
were
recorded.

At
0.09
mg/
kg
b.
w.,
7­
12%
plasma
and
RBC
ChE
inhibition
was
observed
with
three
of
five
volunteers
exhibiting
greater
than
20%
plasma
ChE
inhibition.
Therefore,
0.06
mg/
kg
b.
w.
was
considered
the
NOAEL.
The
Agency
generated
BMD
and
BMDL
estimates
of
0.083
mg/
kg
and
0.069
mg/
kg,
respectively,
based
on
the
RBC
ChE
data
from
the
study.

Critique
of
the
Study
The
scientific
validity
of
this
study
was
analyzed
by
weighing
its
strengths
and
weaknesses
in
order
to
determine
if
the
study
was
sufficiently
robust
to
be
of
use
in
the
Agency's
risk
assessment
for
oxamyl.

Appropriate
endpoints
for
this
study
were
selected.
Acetyl
cholinesterase
inhibition
in
the
nervous
system
was
viewed
as
a
key
molecular
event
in
the
mechanism
of
toxicity
of
carbamate
compounds.
Measurements
of
acetyl
cholinesterase
inhibition
in
both
RBCs
and
brain
are
considered
to
be
biomarkers
of
exposure
for
these
compounds.
In
its
policy
on
the
use
of
data
on
cholinesterase
inhibition
for
risk
assessments
of
organophosphorus
and
carbamate
pesticides
(
USEPA,
2000),
the
Agency
stated
that
it
would
treat
cholinesterase
inhibition
in
the
blood
as
a
surrogate
for
effects
on
the
peripheral
nervous
system
in
animals
and
for
effects
on
the
peripheral
and
central
nervous
system
in
humans.

The
animal
data
for
oxamyl
were
not
available
to
the
Board
to
allow
it
to
make
an
independent
judgment
as
to
whether
the
methods
used
to
determine
acetyl
cholinesterase
inhibition
in
the
animal
studies
and
the
human
study
were
comparable.
According
to
EPA,
however,
the
methods
used
in
the
animal
studies
are
comparable
to
that
in
the
human
study.

Previous
animal
data
was
used
to
predict
that
the
starting
dose
0.005
mg/
kg
would
have
no
detectable
effect
on
humans.
Oral
administration
of
the
compound
is
the
most
predictive
mode
of
administration
since
exposure
to
residues
would
come
from
food
consumption.
There
was
no
justification
for
the
sample
size
of
4
for
oxamyl
for
each
dose
session.

Forty
healthy
males
of
similar
age
and
weight
were
used
in
this
study.
A
weakness
of
this
study
was
that
no
female
subjects
were
used
in
this
study
and
there
was
no
indication
that
any
human
female
data
exists
from
other
studies.
However,
the
Agency
advised
the
Board
that,
based
upon
its
evaluation
of
the
animal
data,
no
sex
differences
would
be
expected.

The
specific
schedule
for
dosing
was
described
in
the
protocol.
It
was
an
ascending
double
blind,
placebo
controlled
study.
Dose
escalation
did
not
occur
if
there
were
clinically
significant
symptoms/
signs
of
toxicity.
Stopping
rules
were
equal
to
or
greater
than
40%
inhibition
of
RBC
cholinesterase
at
a
single
time
point
or
25%
at
two
consecutive
time
points.
If
27
of
69
there
were
associated
symptoms/
signs
of
carbamate
toxicity,
no
further
dose
escalation
would
occur.

A
repeated
measures
analysis
of
variance
was
used
to
analyze
the
percentage
change
from
baseline
in
RBC
and
plasma
cholinesterase
activity,
pupillometry
and
saliva
collection.
At
each
time
point
of
measurements,
a
test
for
linear
trend
with
dose
was
performed
using
a
linear
contrast.
If
the
test
for
linear
trend
was
significant
at
the
5%
significance
level,
the
pairwise
comparisons
at
each
timepoint
were
not
adjusted
for
multiple
comparisons.
Otherwise,
a
Bonferroni
adjustment
was
applied
to
the
pairwise
test
at
the
0.83%
significance
level.

At
0.09
mg/
kg
b.
w.,
7­
12%
plasma
and
RBC
ChE
inhibition
was
observed
with
three
of
five
volunteers
exhibiting
greater
than
20%
plasma
ChE
inhibition.
Therefore,
0.06
mg/
kg
b.
w.
was
considered
the
NOAEL.
The
Agency
generated
BMD
and
BMDL
estimates
of
0.083
mg/
kg
and
0.069
mg/
kg,
respectively,
based
on
the
RBC
ChE
data
from
the
study
The
Board
highlighted
the
strengths
of
the
study
as
follows:

(
a)
The
study
design,
including
both
the
increasing
dose
levels
and
the
time
point
of
observations/
measurements,
was
very
rich
in
information
content
to
allow
evaluation
of
doseresponse
and
estimation
of
the
NOAEL
and
the
dose­
escalation
in
a
step­
wise
fashion
was
scientifically
sound
considering
the
uncertainties
in
the
risk.

(
b)
The
study
had
a
very
clearly
defined
dose­
escalation
scheme
with
properly
justified
stopping
rules.
The
schedule
of
observation
and
measurements
were
frequent
enough
to
give
sufficient
information
on
the
time­
course
effect
of
oxamyl
on
subjects.

(
c)
The
statistical
methods
used
for
analysis,
including
the
adjustment
for
multiple
comparisons
between
placebo
and
active
doses
when
there
was
no
statistical
significance
in
the
linear
trend
test,
were
quite
adequate
for
the
study.

The
Board
highlighted
the
weaknesses
of
the
study
as
follows:

(
a)
There
appeared
to
be
no
specific
justification
for
the
sample
size
of
four
for
oxamyl
for
each
dose
session
and
no
traditional
statistical
test
of
effect
size
regarding
hypotheses.
Because
the
study
was
exploratory
versus
confirmatory,
the
lack
of
justification
was
not
critical.
Nevertheless
it
would
have
been
helpful
to
know
what
effect
size
could
be
detected
between
the
placebo
and
the
active
dose
groups
given
the
sample
size
of
the
study.

(
b)
Because
of
lack
of
justification
for
the
sample
size,
the
lack
of
statistical
significance
in
the
observed
difference
between
placebo
and
active
doses
could
not
be
interpreted
appropriately.
Specifically
the
statement
in
the
Agency
Data
Evaluation
Report
(
Moyer
and
Milznez
2001)
that
"
RBC
cholinesterase
activity
was
statistically
similar
to
placebo
at
all
time
points
in
the
0.005,
0.015,
0.03,
and
0.06
mg/
kg
dose
groups"
was
not
justified
as
the
study
was
not
designed
to
test
for
statistical
similarity.
28
of
69
(
c)
The
Agency
concluded
that
"
there
is
no
indication
from
the
available
rat
data
for
either
oxamyl
or
methomyl
to
suggest
a
sex
difference."
The
animal
data
were
not
supplied
to
the
Board
and
therefore
the
Board
could
not
independently
verify
this
conclusion.
However
the
Board
was
not
uncomfortable
with
accepting
EPA's
conclusions
on
this
matter.

The
Agency
also
concluded
that
"
Given
the
similarity
between
brain
and
RBC
ChE
in
rats,
the
Agency
is
not
aware
of
any
biological
or
physiological
reason
that
human
brain
ChE
would
be
more
sensitive
than
the
rat
brain."
Again
without
seeing
the
animal
data,
the
Board
could
not
verify
this
conclusion
about
rats,
but
the
conclusion
about
human
brain
and
RBC
cholinesterase
was
reasonable
scientifically.

HSRB
Consensus
and
Rationale
Although
the
Board
had
some
questions
about
the
Agency's
conclusions
regarding
lack
of
sex
difference
and
of
the
difference
between
brain
and
RBC
ChE
based
on
only
one
species,
the
Board
supported
the
Agency's
conclusion
that
there
were
no
study
deficiencies
identified
that
would
have
affected
the
outcome
or
conclusions
of
this
study.

Considering
the
high
quality
of
the
design
and
the
conduct
of
the
study,
the
Board
agreed
that
this
intentional
human
dosing
study
of
oxamyl
was
sufficiently
robust
to
be
used
for
reducing
the
10x
inter­
species
(
i.
e.
animal
to
human)
uncertainty
factor
in
the
cumulative
risk
assessment
for
the
N­
methyl
carbamates.

3.2.
Ethical
considerations
Charge
to
the
Board
a.
The
Agency
requested
that
the
Board
provide
comment
on
the
following:

 
Whether
inclusion
in
the
protocol
submitted
to
the
ethics
committee
of
a
factually
inaccurate
statement
regarding
unavailability
of
data
on
accidental
or
incidental
exposure
to
oxamyl
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;

 
Whether
the
absence
from
the
protocol
of
any
discussion
of
the
potential
risks
to
subjects
or
benefits
to
society
of
conducting
the
proposed
research
(
as
required
by
the
Declaration
of
Helsinki,
Principle
#
5)
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;
and
b.
The
Agency
asks
that
the
Board
provide
comment
on
the
following,
taking
into
account
all
that
is
known
about
the
ethical
conduct
of
[
this/
each]
study:

 
OPP's
conclusion
that
there
was
not
clear
and
convincing
evidence
that
the
conduct
of
the
research
was
fundamentally
unethical.
29
of
69
 
Whether
there
was
clear
and
convincing
evidence
that
the
conduct
of
the
study
was
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

Board
Response
to
the
Charge
Study
Overview
The
study
was
performed
by
a
contract
research
organization,
Inveresk
Clinical
Research
of
Edinburgh,
Scotland
and
sponsored
by
the
Haskell
Laboratory
for
Toxicology
and
Industrial
Medicine,
E.
I.
du
Pont
de
Nemours
and
Company,
of
Newark,
Delaware.
The
protocol
documents
specifically
state
that
the
research
was
conducted
in
compliance
with
the
Principles
of
Good
Clinical
Practice
promulgated
by
the
International
Conference
on
Harmonization
(
CMPM/
ICH/
135/
95),
and
the
1996
version
of
the
Declaration
of
Helsinki.
Comments
provided
by
du
Pont
Crop
Protection
(
Dupont
2006),
also
assert
compliance
with
the
1996
version
of
the
Declaration
of
Helsinki.

Critique
of
Study
The
Board
concurred
with
the
factual
observations
of
the
strengths
and
weaknesses
of
the
study,
as
detailed
in
Carley
2006c).
However,
further
comments
are
warranted
regarding:
1)
whether
the
exclusion
of
data
on
accidental
or
incidental
exposure
to
oxamyl
meets
the
legal
definition
of
research
misconduct
prevalent
at
the
time
the
study
was
conducted;
2)
whether
the
escalating­
dose
oral­
exposure
protocol
used
was
designed
to
minimize
risks
to
study
participants;
and
3)
whether
the
documentation
and
process
of
study
subject
enrollment
was
sufficient
to
meet
prevailing
standards
of
voluntary
informed
consent.

1)
Exclusion
of
Available
Data
on
Accidental
or
Incidental
Exposure
Page
15
of
the
original
study
protocol
provided
to
the
independent
ethics
review
committee
established
by
Inveresk
Clinical
Research
included
the
following
statement:
"
No
data
on
accidental
or
incidental
exposure
of
people
to
oxamyl
is
available"
(
McFarlane
and
Freestone
1999).
This
statement
is
false.
Prior
to
the
start
of
the
Randomised
Double
Blind
Ascending
Oral
Dose
Study
with
Oxamyl
in
late
1998,
Du
Pont
submitted
eleven
adverse
event
reports
involving
exposure
of
humans
to
oxamyl
for
inclusion
in
the
EPA's
Office
of
Pesticide
Programs
(
OPP)
Incident
Data
System
(
IDS).
Between
1982
and
1994,
the
State
of
California
Department
of
Food
and
Agriculture's
Pesticide
Illness
Surveillance
Program
recorded
an
additional
61
incidents,
including
30
cases
involving
occupational
exposure
to
oxamyl
alone.
In
comments
provided
to
the
EPA
on
March
31,
2006,
Du
Pont
Crop
Protection
stated
that
"
most
of
the
accidents
or
incidents
reported
in
these
databases
lack
confirmation
of
the
product
involved
or
the
amount
of
product
involved
in
the
exposure.
Also,
some
reports
lack
information
on
symptoms
or
details
of
the
exposure.
Therefore,
none
of
this
data
was
useful
for
designing
the
study."
(
DuPont
2006).
This
latter
statement
may
be
true,
but
the
discounting
of
the
relevance
of
adverse
event
data
from
accidental
or
incidental
exposures
is
ill­
advised
and
borders
on
the
unprofessional.
This
may
have
been
an
appropriate
decision
but
the
data,
evaluation
and
assessment
should
have
been
discussed
in
the
protocol
and
the
consent
document.
Furthermore,
30
of
69
the
statement
in
the
original
study
protocol
remains
untrue.
The
question
before
the
Board,
therefore,
was
whether
or
not
this
misstatement
met
the
legal
definition
of
research
misconduct.

The
Agency
has
accepted
the
federal
policy
on
research
misconduct
(
Classification
No.:
3120.5;
Approval
Date:
03/
18/
2003;
Review
Date:
03/
18/
2006),
as
defined
in
42
CFR
93.103:

Research
misconduct
means
fabrication,
falsification,
or
plagiarism
in
proposing,
performing,
or
reviewing
research,
or
in
reporting
research
results.

(
a)
Fabrication
is
making
up
data
or
results
and
recording
or
reporting
them.

(
b)
Falsification
is
manipulating
research
materials,
equipment,
or
processes,
or
changing
or
omitting
data
or
results
such
that
the
research
is
not
accurately
represented
in
the
research
record.

(
c)
Plagiarism
is
the
appropriation
of
another
person's
ideas,
processes,
results,
or
words
without
giving
appropriate
credit.

(
d)
Research
misconduct
does
not
include
honest
error
or
differences
of
opinion.

Although
the
failure
to
include
the
incidental
exposure
data
may
meet
this
definition
of
falsification,
a
finding
of
research
misconduct
made
under
42
CFR
93.104
requires
that:
1)
there
be
a
significant
departure
from
accepted
practices
of
the
relevant
research
community;
2)
the
misconduct
be
committed
intentionally,
knowingly,
or
recklessly;
and
3)
the
allegation
be
proven
by
a
preponderance
of
the
evidence.
Under
the
standards
outlined
in
42
CFR
93.103­
104,
given
the
limitations
in
the
studies
cited
by
Du
Pont,
and
lack
of
evidence
that
the
absence
of
information
was
intentional,
knowing,
or
reckless,
it
is
the
opinion
of
the
Board
that
this
omission
does
not
meet
the
evidentiary
threshold
necessary
for
a
finding
of
research
misconduct
based
on
falsification.

2)
Minimization
of
Risks
to
Study
Participants
Reasonable
exposure
levels
appear
to
have
been
chosen
using
available
animal
data.
Although
human
exposure
data
from
the
EPA
OPP
IDS
and
California's
Pesticide
Illness
Surveillance
Program
also
may
have
been
useful
in
designing
the
study
so
as
to
minimize
risk
to
research
subjects,
there
was
no
clear
and
convincing
evidence
of
willful
or
blatant
disregard
for
participant
safety.
Adherence
to
a
strict
dose
escalation
protocol,
with
a
stopping
rule
based
on
40%
inhibition
of
RBC
cholinesterase,
reduced
the
likelihood
that
study
subjects
would
experience
unanticipated
adverse
clinical
events.
Based
on
the
knowledge
available
to
investigators
at
the
time
the
study
was
conducted,
this
double­
blind
ascending­
dose
oral
exposure
trial
appears
to
have
been
designed
to
adequately
minimize
potential
risks
to
study
participants.

3)
Voluntary
Informed
Consent
31
of
69
It
was
clear
that
the
written
documentation
for
informed
consent
failed
to
meet
the
standards
outlined
in
Principles
of
Good
Clinical
Practice
(
CMPM/
ICH/
135/
95)
and
the
1996
version
of
the
Declaration
of
Helsinki.

The
information
sheet
that
was
given
to
research
subjects
as
an
appendix
to
the
signed
informed
consent
document
lacked
adequate
discussion
of
the
potential
risks
of
participating
in
the
research
study.
Several
examples
of
what
Board
members
consider
inadequate
discussion
of
potential
risks
are
illustrated
below:

Data
on
incidents
involving
accidental
oxamyl
exposure
were
available
through
both
the
EPA's
OPP
IDS
and
the
California
Pesticide
Illness
Surveillance
Program,
as
previously
discussed.
These
data
included
reports
of
adverse
clinical
events,
including
detailed
reports
of
systemic
effects,
eye
effects
and
dermatological
effects
resulting
from
exposure
to
oxamyl.
These
data
were
not
provided
to
study
participants.

The
background
information
provided
to
study
participants
enrolling
in
both
the
original
and
amended
study
included
the
statement
that
"
results
from
this
study
would
further
confirm
that
the
use
of
oxamyl
for
crop
protection
would
not
pose
an
unreasonable
risk
to
human
health."
(
McFarlane
and
Freestone
1999).
Although
the
informed
consent
document
clearly
stated
that
this
is
the
first
study
involving
intentional
exposure
of
human
subjects,
particularly
given
the
incident
data
discussed
above,
this
statement
as
written
might
have
inappropriately
downplayed
concerns
that
study
participants
might
have
with
regard
to
participation.

Study
participants
enrolling
in
the
amended
study,
designed
to
look
for
clinical
or
biological
outcomes
associated
with
exposure
to
0.15
mg/
kg
body
weight
of
oxamyl,
were
informed
that
"
no
significant
side
effects
[
were]
noticed
in
any
of
[
the
previous
lower]
dose
levels."
(
McFarlane
and
Freestone
1999).
Previous
trial
participants
receiving
0.09
mg/
kg
body
weight
of
oxamyl
exhibited
4­
24%
and
12­
22%
RBC
and
plasma
cholinesterase
inhibition.
The
study
investigators
concluded
that
these
observed
levels
of
cholinesterase
inhibition
did
not
qualify
as
adverse
events
because
of
the
variability
in
the
data,
but
they
also
state
that
the
level
of
inhibition
observed
in
study
participants
receiving
0.09
mg/
kg
body
weight
of
oxamyl
achieved
statistical
significance.
Because
the
consent
form
described
cholinesterase
inhibition
as
a
side
effect
of
oxamyl
exposure,
it
can
be
argued
that
this
information
should
have
been
provided
to
subjects
participating
in
the
0.15
mg/
kg
dose
study.

The
letter
to
the
subjects'
general
practitioner
contained
no
information
about
the
actual
study
and
the
product
being
administered
other
than
the
name
of
the
compound.
It
thus
minimized
the
extent
to
which
the
opinion
of
the
general
practitioner
could
protect
the
research
subject.

In
hindsight,
it
is
clear
that
the
documentation
provided
failed
to
rigorously
meet
the
standards
of
voluntary
informed
consent
applicable
to
studies
conducted
in
Scotland
in
1998­
1999.
However,
there
was
no
clear
and
convincing
evidence
that
these
deficiencies
knowingly
and
seriously
impaired
the
informed
consent
process.

HSRB
Consensus
and
Rationale
32
of
69
The
Board
concluded
that:

a)
The
oxamyl
human
toxicity
study
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted,
however
b)
There
was
no
clear
or
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained,
and
c)
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted)
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

Although
the
study
failed
to
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted,
including
those
cited
in
the
study
protocol
itself,
the
Board
concurred
with
the
assessment
of
the
Agency
that
there
was
no
clear
and
convincing
evidence
that
the
conduct
of
the
research
was
fundamentally
unethical
in
that
it
was
not
intended
to
harm
subjects
nor
failed
entirely
to
obtain
informed
consent.

It
is
believed
that
potential
risks
to
study
participants
were
inadequately
addressed
in
the
documents
provided
to
research
participants
at
enrollment,
thus
impairing
the
informed
consent
process.
Nevertheless,
the
Board
believed
that
there
was
no
clear
and
convincing
evidence
to
suggest
that
the
study
investigators
failed
to
obtain
voluntary
informed
consent
from
all
research
participants.

The
Board
was
of
the
opinion
that
the
deficiencies
noted
above
are
unlikely
to
have
resulted
in
serious
harm
to
study
participants,
based
on
the
knowledge
available
to
the
investigators
at
the
time.

The
Board
concluded
that
there
is
no
obvious
reason
why
the
Agency
cannot
rely
on
the
results
of
this
study,
as
appropriate
under
current
pesticide
laws,
given
the
absence
of
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical
or
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

4.
Azinphos­
Methyl
Charge
to
the
Board
Azinphos
methyl
(
AZM)
is
an
organophosphate
pesticide
(
OP).
Consistent
with
other
OPs,
AZM
elicits
neurotoxicity
through
the
inhibition
of
the
enzyme,
acetylcholinesterase,
via
phosphorylation
of
the
active
site.
At
sufficiently
high
doses,
exposure
to
AZM
can
lead
to
a
variety
of
clinical
signs.
The
Agency
is
developing
an
assessment
to
estimate
risk
to
workers
from
exposure
to
AZM.
In
addition,
AZM
is
a
member
of
the
OP
common
mechanism
group
and
is
thus
included
in
the
cumulative
risk
assessment
for
the
OPs.
33
of
69
Scientific
considerations
The
Agency's
WOE
document
and
DER
for
AZM
describe
the
study
design
and
results
of
the
AZM
repeat
dose,
oral,
human
toxicity
study.
The
WOE
document
also
discussed
the
Agency's
conclusions
regarding
the
usefulness
of
the
human
study
in
the
worker
risk
assessment
and
in
the
cumulative
risk
assessment
for
the
OPs.
For
AZM,
the
Agency
has
concluded
that
the
human
toxicity
study
was
appropriate
for
developing
a
point
of
departure
for
extrapolation
of
risk
to
workers
exposed
to
AZM
via
the
dermal
and
inhalation
routes.
For
the
cumulative
risk
assessment,
the
Agency
has
determined
that
because
no
cholinesterase
inhibition
was
seen
in
the
human
toxicity
study,
it
was
not
possible
to
evaluate
whether
steady
state
had
been
reached
in
humans
at
28
days
of
exposure.
Thus,
the
Agency
had
concluded
that
the
AZM
repeat
dose,
oral,
toxicity
study
was
not
sufficiently
robust
for
informing
the
inter­
species
factor
in
the
cumulative
risk
assessment
of
the
OPs.

Please
comment
on
the
scientific
evidence
that
supports
the
conclusions
for:

a.
the
use
of
the
human
toxicity
study
to
develop
a
point
of
departure
for
extrapolation
of
risk
to
workers
in
the
worker
risk
assessment
and
b.
the
determination
that
the
human
toxicity
study
cannot
be
used
to
inform
the
interspecies
factor
in
the
cumulative
risk
assessment.

Board
Response
to
the
Charge
Brief
Overview
of
the
Study
In
a
repeat
dose
oral
human
toxicity
study,
conducted
in
1999
by
the
Inveresk
Laboratory
(
McFarlane
&
Freestone,
1999b),
four
males
were
dosed
with
a
placebo
(
lactose)
and
eight
males
were
dosed
with
0.25
mg/
kg/
day
of
AZM
for
28
consecutive
days.
The
sole
dose
of
0.25
mg/
kg
was
chosen
based
on
the
results
of
a
subchronic
rat
study
and
an
earlier
study
with
human
subjects
that
indicated
this
would
be
a
NOAEL
for
inhibition
of
plasma
and
RBC
cholinesterase.
Previous
human
studies
were
conducted
in
1972
and
1974
and
regulatory
agencies
were
reluctant
to
rely
on
the
data
"
due
to
deficiencies
in
documentation,
specifically
the
availability
of
raw
data
and
the
lack
of
GLP
compliance."

Dosing
was
orally
by
capsule
and
the
subjects
were
housed
in
a
clinic
throughout
the
dosing
period.
The
subjects
were
monitored
for
reactions
and
samples
of
blood
were
taken
at
predose
(
eight
times)
and
daily
throughout
the
dosing
period.
On
some
days,
a
blood
sample
was
taken
both
prior
to
administering
the
dose
and
four
hours
later.
Both
plasma
cholinesterase
(
ChE)
and
RBC
acetylcholinesterase
(
AChE)
were
measured.
In
addition,
hematology,
clinical
chemistry,
and
urinalysis
were
evaluated
as
well
as
blood
pressure
and
electrocardiogram
(
ECG).
There
were
no
reactions
to
treatment
and
blood
pressure
and
ECG
were
not
affected.
Eight
of
the
12
volunteers
were
noted
to
have
symptoms
of
a
viral
infection
and
some
were
treated
with
paracetamol.
The
postdosing
group
mean
data
were
compared
three
ways
in
an
effort
to
see
if
AZM
caused
inhibition
of
either
plasma
ChE
or
RBC
AChE.
None
of
the
comparisons
indicated
inhibition
of
either
measure.
Also,
samples
taken
four
hours
after
dosing
did
not
indicate
34
of
69
inhibition.
It
was
concluded
that
a
dose
of
0.25
mg/
kg/
day
for
28
days
did
not
result
in
either
clinical
symptoms
or
inhibition
of
either
plasma
ChE
or
RBC
AChE
in
human
males,
so
that
this
dose
could
be
considered
a
NOAEL.

Critique
of
the
Study
One
strength
of
the
study
was
its
design
as
a
randomized,
double
blind
study
including
a
placebo
group.
The
clear
inclusion
and
exclusion
criteria
for
subject
selection
appeared
to
have
been
chosen
to
reduce
the
likelihood
of
confounding
factors.
The
subjects
were
in
good
health,
were
not
using
prescription
or
illicit
drugs,
were
non­
smokers,
and
were
not
agricultural
workers
or
pesticide
applicators
who
might
have
experienced
OP
exposure
within
the
preceding
month.
Subjects
resided
in
the
clinic
from
the
day
before
study
start
to
24
hours
after
the
last
dose
was
administered,
received
a
standardized
diet,
and
were
under
medical
and
nursing
supervision
throughout.

The
assessment
of
critical
outcomes
was
comprehensive,
involving
a
general
clinical
exam,
measurement
of
systolic
and
diastolic
blood
pressure,
the
administration
of
an
ECG,
and
various
blood
and
urine
studies.
Multiple
measurements
were
made
of
plasma
ChE
and
RBC
AChE,
namely
on
8
pre­
dose
days
then
daily
4
hours
after
dosing.
Moreover,
on
12
post­
dosing
days,
two
blood
samples
were
taken,
one
before
the
dose
and
one
4
hours
afterwards.

Possible
group
differences
in
plasma
ChE
and
RBC
AChE
were
evaluated
in
several
ways,
both
in
grouped
and
individual
data:
a)
Comparison
of
the
day­
to­
day
ChE
activities
within
the
AZM
group
to
the
same
day
values
in
the
control
group
b)
Comparison
of
same
day
predosing
ChE
activities
with
ChE
activities
4
hours
after
dosing
c)
Comparison
of
the
day­
to­
day
ChE
activities
values
within
the
AZM
group
to
predosing
baseline
value.

Several
weaknesses
were
identified
in
the
study.
First,
the
subjects
were
all
male,
however
there
have
been
no
consistent
sex
differences
in
sensitivity
with
regard
to
inhibition
of
plasma
or
RBC
cholinesterase
in
animal
studies
(
at
higher
dose
levels
that
elicit
more
serious
toxicity,
there
are
gender­
related
differences
in
responses).
The
sample
size
was
not
large,
involving
only
12
adult
males
(
four
in
the
placebo
group,
eight
in
the
AZM
group),
raising
a
concern
that
the
statistical
power
might
have
been
inadequate
to
detect
a
modest
degree
of
inhibition
in
the
AZM
group.

The
standard
deviations
of
the
ChE
levels
were
large,
as
great
as
20%
for
plasma
ChE
and
15%
for
RBC
ChE,
reducing
confidence
in
the
consistency
of
these
endpoints.

A
variety
of
symptoms
were
reported
over
the
course
of
the
study,
with
the
majority
occurring
in
subjects
administered
AZM.
The
conclusion
drawn
in
the
Agency's
Data
Evaluation
Record
(
Doherty
1999)
that
none
of
the
symptoms
likely
reflected
effects
of
AZM
was
not
verifiable,
nor
was
it
convincing.
35
of
69
Certain
aspects
of
the
statistical
analyses
are
problematic.
For
the
analyses
of
percentage
change
each
day
from
baseline
(
predosing)
plasma
and
RBC
cholinesterase
activity
in
the
subjects
receiving
AZM,
the
choice
of
repeated
measures
ANOVA
as
the
statistical
approach
was
appropriate
given
the
structure
of
the
data.
This
would
have
allowed
each
subject
to
be
used
as
his
own
control,
but
this
does
not
appear
to
be
the
way
the
analyses
were
done.
The
pooled
baseline
RBC
and
plasma
ChE
values
were
used
as
covariates
rather
than
individual
subject
values.
This
essentially
ignores
the
value
of
the
individual
levels
in
increasing
statistical
power
by
taking
account
of
pre­
dosing
inter­
individual
differences
in
ChE
levels.
The
other
two
types
of
analyses
conducted
were
not
limited
by
this
deficiency,
but
the
analysis
of
within­
subject
change
from
baseline
is
potentially
the
most
sensitive
analysis
in
this
study.

In
proposing
to
use
the
results
of
this
study
for
dermal
and
inhalation
risk
assessment,
the
Agency
applied
a
dermal
absorption
factor
of
42%
based
on
a
rat
study
and
an
inhalation
absorption
factor
of
100%.
Bayer
Crop
Science
commented
that
data
are
available
supporting
a
lower
estimate
of
human
dermal
absorption
(
21.5%)
but
these
data
were
not
available
for
evaluation
by
the
Board.
Another
concern
was
whether
the
effects
of
a
single
oral
dose
administered
daily
provide
a
reasonable
estimate
of
the
effects
of
the
continuous
dosing
via
all
routes
of
exposure
that
would
be
experienced
by
agricultural
workers.

The
major
concern
regarding
this
human
study
was
it
was
designed
to
demonstrate
a
NOAEL.
No
LOAEL
could
be
established
to
validate
the
NOAEL
because
only
one
dose
was
used.
The
fact
that
inhibition
was
not
observed
at
the
single
dose
used
raised
concern
about
sensitivity
of
the
methods
used.
The
Agency
was
reassured
by
the
laboratory's
observation
of
plasma
and
RBC
cholinesterase
inhibition
in
other
studies
of
carbamates
and
organophosphates,
including
aldicarb,
methomyl,
and
oxamyl.
Nevertheless,
it
is
not
possible
to
be
sure
if
the
absence
of
an
effect
in
this
study
was
because
the
methods
used
were,
for
some
reason,
not
up
to
the
standards
of
those
used
in
the
other
studies,
and
therefore
less
sensitive.

HSRB
Consensus
and
Rationale
The
Board
concluded
that:

a.
Data
from
the
28­
day
repeat
oral
dose
study
of
AZM
should
not
be
used
in
developing
a
point
of
departure
for
extrapolation
of
risk
to
workers
exposed
to
AZM
via
the
dermal
and
inhalation
routes.

b.
Data
from
the
28­
day
repeat
oral
dose
study
of
AZM
cannot
be
used
to
inform
the
inter­
species
factor
in
the
cumulative
risk
assessment.

Despite
the
study's
strengths,
the
HSRB
had
only
limited
confidence
in
the
inferences
that
can
be
drawn
from
this
study,
in
large
part
because
only
one
AZM
dose
was
used.
In
order
to
use
these
data,
one
must
assume
that
the
lab
would
have
detected
inhibition
had
it
been
present
at
the
single
dose
administered.
The
conclusions
drawn
could
be
correct,
but
this
cannot
be
determined
with
certainty.
The
conclusion
that
this
study
is
not
appropriate
for
developing
a
point
of
departure
for
either
the
worker
risk
assessment
or
the
cumulative
risk
assessment
is
36
of
69
consistent
with
the
recommendation
of
the
NAS
committee
(
NAS
2001)
that
the
Agency
should
not
consider
data
from
NOEL­
only
studies.

Ethical
considerations
Charge
to
the
Board
a.
The
Agency
requests
that
the
Board
provide
comment
on
the
following:

Whether
the
informed
consent
materials
 
which
refer
to
"
the
company"
and
"
supervising
doctor"
without
further
identification,
and
contain
no
discussion
of
who
would
benefit
from
the
research
 
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;
and,

Whether
the
absence
from
the
protocol
of
any
discussion
of
the
potential
risks
to
subjects
or
benefits
to
society
of
conducting
the
proposed
research
(
as
required
by
the
1996
Declaration
of
Helsinki,
Principle
#
5,
with
which
the
research
asserted
compliance)
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;
and
b.
The
Agency
asks
that
the
Board
provide
comment
on
the
following,
taking
into
account
all
that
is
known
about
the
ethical
conduct
of
[
this/
each]
study:

OPP's
conclusion
that
there
was
not
clear
and
convincing
evidence
that
the
conduct
of
the
research
was
fundamentally
unethical.

Whether
there
was
clear
and
convincing
evidence
that
the
conduct
of
the
study
was
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

Brief
Overview
of
the
Study
As
noted
above,
the
study
was
conducted
in
1999
by
a
contract
research
organization,
Inveresk
Clinical
Research
of
Edinburgh,
Scotland,
at
its
Elphinstone
Research
Centre
in
Tranent.
The
study
sponsor
was
the
Bayer
Corporation,
Agricultural
Division,
of
Stilwell,
Kansas.
The
protocol
documents
specifically
state
that
the
research
was
conducted
in
compliance
with
the
guideline
for
Good
Clinical
Practice,
and
in
accordance
with
the
guidelines
of
the
Declaration
of
Helsinki,
1964,
as
amended
through
1996.

Critique
of
Study
The
Board
concurred
with
the
factual
observations
of
the
strengths
and
weaknesses
of
the
study,
as
detailed
in
Carley
(
2006d).
However,
further
comments
are
warranted
with
regard
to
whether
the
documentation
and
process
of
study
subject
enrollment
was
sufficient
to
meet
prevailing
standards
of
voluntary
informed
consent.
37
of
69
It
is
clear
that
the
written
documentation
for
informed
consent
failed
to
meet
fully
the
standards
contained
in
the
1996
version
of
the
Declaration
of
Helsinki.

In
particular,
the
information
sheet
that
was
given
to
research
subjects
as
an
appendix
to
the
signed
informed
consent
document
contained
the
following
statement
under
the
subheading
Aim:
"
The
aim
of
the
study
is
to
establish
a
recommended
daily
intake
following
long
term
dietary
exposure
and
to
determine
the
most
appropriate
way
of
assessing
workers
exposure."
By
using
the
phrase
"
recommended
daily
intake,"
this
statement
would
appear
to
suggest
that
it
is
actually
desirable
to
consume
a
daily
minimum
amount
of
the
study
compound.
This
sentence
is
thus
misleading.
However,
other
portions
of
the
information
sheet
made
it
clear
that
the
study
compound
was
a
pesticide,
and
that
consuming
it
is
not
good
for
people,
thus
leading
the
Board
to
conclude
that
this
one
sentence
by
itself
does
not
provide
clear
and
convincing
evidence
that
the
consent
process
as
a
whole
was
significantly
deficient
relative
to
the
ethical
standards
prevailing
at
the
time
the
study
was
conducted.

HSRB
Consensus
and
Rationale
The
Board
concluded
that:

a)
The
azinphos­
methyl
human
toxicity
study
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted.

b)
There
was
no
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained.

c)
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted)
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

The
Board
determined
that
the
informed
consent
materials
 
which
refer
to
"
the
company"
and
"
supervising
doctor",
without
further
identification,
and
which
contain
no
discussion
of
who
would
benefit
from
the
research
 
did
not
fully
comply
with
the
ethical
standards
at
the
time.
However,
the
Board
did
not
find
clear
and
convincing
evidence
that
the
level
of
non­
compliance
should
be
considered
significantly
deficient
relative
to
those
thenprevailing
ethical
standards.
With
regard
to
the
use
of
the
terms
"
the
company"
and
"
supervising
doctor,"
this
type
of
language,
though
highly
undesirable,
is
unfortunately
not
uncommon,
even
at
the
present.
With
regard
to
the
benefit
issue,
the
Board
determined
that
the
consent
materials,
while
far
from
ideal,
did
in
fact
somewhat
address
this
issue.
They
indicate,
for
example,
that
the
study
may
lead
to
further
information
about
the
risk
that
this
compound
poses
to
workers
and
consumers.

The
Board
determined
that
the
absence
from
the
protocol
of
discussion
of
the
potential
risks
to
subjects
or
benefits
to
society
of
conducting
the
proposed
research
(
as
required
by
the
Declaration
of
Helsinki,
Principle
#
5)
should
not
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.
The
potential
risks
and
benefits
38
of
69
are
described
in
the
research
subject
information
sheet/
informed
consent
document.
While
not
in
the
protocol
itself,
they
are
nonetheless
included
in
the
materials
provided
to
the
ethics
committee
(
and
to
the
potential
research
subject).
Thus
the
ethics
committee
and
the
potential
research
subjects
had
the
opportunity
to
weigh
the
risks
and
benefits.

The
Board
concluded
that
there
was
no
obvious
reason
why
the
Agency
cannot
rely
on
the
results
of
this
study,
as
appropriate
under
current
pesticide
laws,
given
the
absence
of
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical
or
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

5.
DDVP
Charge
to
the
Board
Like
AZM,
DDVP
is
an
organophosphate
pesticide
(
OP)
which
elicits
neurotoxicity
through
the
inhibition
of
acetylcholinesterase,
via
phosphorylation
of
the
active
site.
The
Agency
is
conducting
an
aggregate
(
single
chemical,
multi­
route,
multi­
duration)
risk
assessment
of
DDVP.
In
addition,
DDVP
is
a
member
of
the
OP
common
mechanism
group
and
is
thus
included
in
the
cumulative
(
multi­
chemical,
multi­
route)
risk
assessment
for
the
OPs.

5.1.
Scientific
considerations
a.
The
Agency's
WOE
document
and
DER
for
DDVP
described
the
study
design
and
results
of
the
DDVP
repeat
dose
oral
human
study.
The
WOE
document
also
discussed
the
Agency's
conclusions
regarding
the
usefulness
of
this
study
in
the
aggregate
risk
assessment
and
in
the
cumulative
risk
assessment
for
the
OPs.
For
the
single
chemical
risk
assessment,
the
Agency
had
concluded
that
the
human
study
was
sufficiently
robust
for
developing
a
point
of
departure
for
estimating
dermal,
incidental
oral,
and
inhalation
risk
from
exposure
to
DDVP
in
the
single
chemical
risk
assessment.
For
the
cumulative
risk
assessment,
the
Agency
had
determined
that
results
of
the
DDVP
multi­
dose
human
toxicity
study
do
not
support
reducing
the
default
10X
inter­
species
factor
in
the
cumulative
risk
assessment
of
the
OPs.

Please
comment
on
the
scientific
evidence
that
supports
the
conclusions
for:

a)
the
Agency's
conclusions
for
use
of
the
human
study
for
developing
a
point
of
departure
for
estimating
risk
in
the
single
chemical,
aggregate
risk
assessment
and
b)
the
Agency's
determination
that
the
human
study
cannot
be
used
to
reduce
the
interspecies
factor
in
the
cumulative
risk
assessment.

Board
Response
to
the
Charge
Study
Overview
A
single
blind,
randomized
placebo­
controlled
oral
study
was
conducted
with
DDVP
in
which
six
healthy
male
volunteers
were
administered
a
daily
dose
of
DDVP
at
approximately
39
of
69
0.1mg/
kg/
day
and
three
volunteers
were
administered
a
placebo
(
Gledhill
1997).
DDVP
was
dissolved
in
corn
oil
and
administered
daily
in
a
gelatin
capsule
to
fasted
subjects
(
subjects
did
not
eat
after
midnight
prior
to
each
morning
dose)
for
a
total
of
21
days.
Blood
samples
were
collected
for
analysis
of
red
blood
cell
(
RBC)
cholinesterase
activity.
For
each
subject,
the
baseline
level
of
RBC
cholinesterase
activity
was
established
from
seven
pre­
dose
samples,
and
a
single
blood
sample
was
collected
approximately
24
hours
after
dosing
(
just
prior
to
dosing
on
the
following
day)
on
days
1,
2,
4,
7,
9,
11,
14,
16
and
18
of
the
study.
No
blood
samples
were
collected
on
the
last
three
days
of
the
study
(
days
19­
21).
After
cessation
of
dosing,
subjects
returned
approximately
1
week
later
(
on
or
about
day
25)
for
a
follow­
up
analysis
of
RBC
cholinesterase
activity.
The
criterion
for
withdrawal
from
the
study
was
inhibition
of
RBC
cholinesterase
activity
of
20%
or
more
on
a
given
day's
analysis
followed
by
a
further
decrease
in
activity
in
the
next
successive
sample.
A
linear
mixed
model
was
fitted
to
the
cholinesterase
activity
and
significant
differences
were
found
within
subjects
and
also
between
groups
(
treatment
versus
placebo
subjects)
for
pre­
dose
and
post­
dose
cholinesterase
activity.

Critique
of
Study
The
scientific
validity
of
the
repeated
dose
study
for
DDVP
was
determined
by
the
relative
strengths
and
weakness
of
the
design
and
conduct
of
the
study.

The
strengths
of
the
study
were
considered
to
be
as
follows:
 
The
repeat
dosing
paradigm
affords
the
opportunity
to
more
critically
evaluate
the
sustained
nature
of
RBC
cholinesterase
inhibition
associated
with
OPs.
 
The
analysis
of
RBC
cholinesterase
activity
is
fairly
robust,
given
the
assessment
of
predose
baseline
values
on
7
separate
occasions.
The
baseline
values
were
fairly
consistent
both
within
and
between
subjects
(
16,000
 
21,000
IU).
 
A
low,
but
statistically
significant
effect
was
observed
in
RBC
cholinesterase
inhibition.

There
are,
however,
numerous
weaknesses
of
the
study
that
are
relevant
to
the
utility
of
these
data
in
establishing
a
point
of
departure
for
use
in
single
chemical,
aggregate
and
cumulative
risk
assessments
for
DDVP.
These
weaknesses
included:

 
A
single
dosage
was
used,
preventing
establishment
of
dose­
response
relationships.

 
The
sample
size
was
small
and
included
only
male
volunteers.
In
this
regard,
it
was
not
clear
whether
the
study
was
properly
powered,
given
that
no
sample
size
calculations
seem
to
have
been
used
in
order
to
arrive
at
the
number
of
volunteers
used
in
the
study.

 
RBC
cholinesterase
inhibition
was
determined
only
at
24
hours
post
dosing.
Although
organophosphates
are
known
to
show
prolonged
inhibition
of
cholinesterase
activity,
it
was
not
clear
whether
the
peak
of
RBC
cholinesterase
was
established.

 
The
sponsor
did
not
include
the
analysis
of
plasma
cholinesterase
measurements
in
the
study.
The
reason
for
this
omission
was
not
clear,
and
it
was
noted
that
virtually
every
toxicological
and
exposure
assessment
study
that
has
focused
on
cholinesterase
inhibition
due
to
organphosphorus
insecticides
includes
measurement
of
both
plasma
(
serum)
40
of
69
cholinesterase
and
RBC
cholinesterase.
The
combination
of
these
measurements
has
been
used
routinely
for
risk
assessments
by
numerous
regulatory
agencies,
including
the
EPA,
as
well
as
by
clinicians
who
diagnose
pesticide
poisonings.
Current
worker
surveillance
programs
in
some
states
(
California
and
Washington)
require
measurement
of
both
plasma
and
erythrocyte
cholinesterase,
and
both
measurements
are
used
in
combination
to
initiate
workplace
investigations
and
remove
workers
from
pesticide­
related
job
activities
until
enzyme
activities
return
to
baseline.

 
Sampling
was
incomplete
because
the
last
day
of
analysis
of
enzyme
inhibition
was
day
18
but
dosing
continued
until
day
21.
It
is
not
clear
whether
any
additional
decrease
in
enzyme
activity
would
have
been
observed
on
days
19­
21.
In
the
sampling
schedule
outlined
above,
the
maximum
time
gap
between
samples
during
the
dosing
period
(
days
1­
21)
was
three
days
(
between
days
11
and
14).
Logically
then,
an
additional
sample
would
have
been
taken
on
day
21
or
22,
the
time
in
the
study
when
maximum
effects
might
be
observed.
In
this
regard,
two
subjects
presented
with
inhibition
values
of
22
and
23%,
exceeding
the
20%
cut­
off
for
subsequent
analysis
and
consideration
for
withdrawal
on
day
18
of
the
study.
The
lack
of
additional
measurements
in
these
subjects
during
the
remainder
of
the
dosing
period
was
scientifically
inadequate
and
ethically
troublesome.

 
It
is
neither
clear
nor
convincing
that
steady
state
inhibition
of
RBC
cholinesterase
activity
was
achieved
in
the
study.
The
data
suggest
that
the
level
of
enzyme
inhibition
was
still
increasing,
particularly
in
the
time
period
from
11­
18
days,
with
a
difference
of
16%
in
activity
on
Day
18
compared
to
pre­
dose
values.
Dosing
was
stopped
on
Day
21,
with
no
further
analysis
until
approximately
4
days
after
cessation
of
dosing.
Although
the
difference
in
activity
between
day
18
post­
dose
and
the
average
of
the
pre­
dose
measurements
was
deemed
to
be
"
not­
biologically
significant"
by
the
study
sponsor,
the
possibility
that
RBC
cholinesterase
inhibition
may
have
reached
or
exceeded
20%
by
the
end
of
the
study
cannot
be
excluded.

 
There
was
a
lack
of
appropriate
follow­
up
in
all
subjects
in
this
study.
As
noted
earlier,
two
subjects
presented
with
inhibition
values
of
22
and
23%,
exceeding
the
20%
cut­
off
for
subsequent
analysis
and
consideration
for
withdrawal
on
Day
18.
However,
there
were
no
additional
analyses
of
RBC
cholinesterase
activity
in
these
individuals
on
days
19­
21
of
dosing.
Additionally,
a
blood
sample
was
collected
within
4
to
10
days
following
completion
of
the
21­
day
dosing
period
for
all
subjects.
The
mean
inhibition
of
the
enzyme
observed
at
seven
days
following
cessation
of
dosing
was
17%,
suggesting
little
if
any
recovery
of
enzyme
at
this
time,
but
these
data
were
not
analyzed
for
statistical
significance.
Furthermore,
one
subject
ended
his
participation
in
the
study
(
day
25)
with
RBC
cholinesterase
inhibition
greater
than
20%.
In
all
cases,
there
was
no
additional
follow­
up
of
the
subjects
after
the
single
post­
dose
analysis
of
cholinesterase
activity.

HSRB
Consensus
and
Rationale
The
Board
concluded
that:
41
of
69
a)
The
DDVP
repeat
dose
human
toxicity
study
was
sufficiently
robust
for
developing
a
point
of
departure
for
estimating
dermal,
incidental
oral,
and
inhalation
risk
from
exposure
to
DDVP
in
the
single
chemical
risk
assessment.

In
specific
response
to
the
Agency's
charge
question,
the
HSRB
concluded
that
there
were
numerous
technical
limitations
to
the
data
obtained
in
the
study.
In
addition
to
the
weaknesses
of
the
study
design
and
execution
outlined
above,
the
HSRB
concluded
that
the
evaluation
of
only
a
single
dose
level
of
DDVP
along
with
the
omission
of
plasma
cholinesterase
measurements
greatly
limit
the
value
of
this
study
in
terms
of
producing
new
knowledge
that
can
be
used
in
the
regulatory
process
and
in
medical
diagnosis.
Furthermore,
study
investigators
have
an
obligation
to
design
a
study
that
provides
appropriate
oversight
of
subjects
until
indications
of
the
effects
of
the
administered
dose
are
no
longer
present,
and
the
Board
considered
that
the
design
of
this
study
which
continued
intentional
dosing
without
collection
of
blood
samples
for
cholinesterase
analysis
was
not
defensible
scientifically.
Following
considerable
discussion,
the
HSRB
concluded
that
the
dosage
evaluated
in
the
repeat
dosing
human
study
can
be
used
as
a
LOAEL
for
the
single
chemical
aggregate
risk
assessment
for
DDVP.
Although
a
study
using
a
single
dose
level
is
not
ideal
for
establishing
a
LOAEL,
there
was
general
consensus
that
RBC
cholinesterase
is
a
well­
characterized
endpoint
for
compounds
that
inhibit
acetylcholinesterase
activity
and
therefore,
because
the
decreased
activity
in
RBC
cholinesterase
activity
observed
in
this
study
was
at
or
near
the
limit
of
what
could
be
distinguished
from
baseline
values,
it
was
unlikely
that
a
lower
dose
would
produce
a
measurable
effect
in
RBC
cholinesterase
activity.
However,
the
HSRB
strongly
recommended
that,
in
most
cases,
studies
in
human
subjects
designed
to
define
the
NOAEL
or
LOAEL
for
a
compound
should
include
more
than
a
single
dose
level.

b)
Results
of
the
DDVP
repeat­
dose
human
toxicity
study
should
not
be
used
to
support
reducing
the
default
10X
inter­
species
factor
in
the
cumulative
risk
assessment
of
the
organophosphate
pesticides.

Although
the
data
obtained
in
this
study
can
be
used
to
establish
a
point
of
departure
for
the
single
chemical
aggregate
risk
assessment,
the
consensus
of
the
HSRB
was
that
the
scientific
limitations
of
the
study
design
do
not
justify
its
use
in
the
cumulative
risk
assessment.
In
particular,
the
lack
of
sample
collection
through
to
the
completion
of
dosing,
the
lack
of
a
clear
demonstration
that
steady
state
inhibition
of
RBC
cholinesterase
inhibition
had
been
achieved,
and
the
lack
of
any
dose­
response
data
limit
the
overall
utility
of
the
human
data.
Accordingly,
the
HSRB
recommended
that
the
default
interspecies
uncertainty
factor
should
be
applied
for
the
cumulative
risk
assessment
for
DDVP.

Charge
to
the
Board
b.
The
Agency
has
concluded
that
other
human
studies
made
available
to
the
Board
do
not
provide
sufficient
scientifically
sound
information
to
warrant
any
reduction
in
the
10X
interspecies
uncertainty
factor
used
to
derive
reference
dose
values
for
DDVP
based
on
animal
toxicity
endpoints.
42
of
69
Please
comment
on
the
scientific
evidence
that
supports
these
conclusions.

Board
Response
to
the
Charge
HSRB
Consensus
and
Rationale
The
HSRB
concluded
that
the
other
DDVP
human
toxicity
studies
available
for
the
Board's
consideration
should
not
be
used
for
determining
a
reduction
in
the
10X
uncertainty
factor
to
derive
reference
dose
values
for
DDVP
based
on
animal
toxicity
endpoints.

The
Board's
deliberations
for
this
question
focused
on
the
acceptability
or
not
of
these
human
studies
for
the
Agency's
intended
purposes,
rather
than
on
the
evaluation
of
the
magnitude
of
the
interspecies
uncertainty
factor.
Since
the
results
of
animal
studies
or
benchmark
dose
modeling
were
not
provided
to
the
Board,
the
review
was
restricted
to
the
evaluation
of
the
acceptability
of
the
human
studies
for
the
intended
purposes.
The
Board
concluded
these
other
human
studies
did
not
warrant
use
in
determining
the
inter­
species
uncertainty
factor
because
of
policy
considerations
(
e.
g.,
exposures
involving
infants,
children,
pregnant
women)
or
due
to
uncertainty
associated
with
the
study
itself
(
e.
g.,
inappropriate
duration,
questionable
route,
exposure
data
of
limited
utility,
lack
of
time
course
data
on
critical
effect).
Board
concerns
regarding
these
other
human
studies
are
provided
in
Table
1.
43
of
69
Table
1.
Evaluation
of
Specific
DDVP
Human
Studies
Provided
to
the
HSRB
Reference
Observations/
Concerns
Gledhill
Acute
toxicity
study
Insufficient
time
course
measurements
of
cholinesterase
Cavagna
(
1970)
Conducted
in
newborns
Slomka
(
1981)
Exposure
through
plastic
bead
(
polyvinyl
resin)
formulation;
rate
of
absorption
not
known;
data
provided
as
ranges
Cervoni
(
1969)
Efficacy
trial;
measurement
of
cholinesterase
inhibition
not
the
main
focus;
no
assurance
of
consistent
methods
of
measurement
of
inhibition
Leary
(
1974)
Exposure
via
insecticide
strips;
possibility
children
were
involved,
but
composition
of
families
not
given;
inhalation
route
 
caveat
of
dose
calculations;
no
information
on
consent
of
subjects
Smith
(
1972)
Performed
in
altitude
chamber;
short
term
inhalation
study;
no
information
on
consent
of
subjects
Cavagna
(
1969)
Exposure
via
insecticide
strips
included
pregnant
women,
infants
and
children
in
a
hospital
Pena­
Chavarria
(
1969)
Exposure
of
patients
(
most
of
them
anemic,
treated
for
parasite
infection);
not
designed
to
identify
NOAEL
or
LOAEL
Stein
(
1966)
Insufficient
information
on
the
time
course
of
cholinesterase
inhibition;
doses
not
quantitated
Funckes
(
1963)
Study
population
included
children,
some
below
six
years;
time
course
evaluation
on
inhibition
insufficient
Witter
(
1961)
Simulated
aircraft
cabin;
one
hour
exposures;
time
course
information
lacking
Gratz
(
1963)
Inadequate
information
to
evaluate
dose
and
NOAEL;
inadequate
information
about
how
many
people
exposed
at
each
concentration;
single
application­
based
exposures
5.2.
Ethical
considerations
Charge
to
the
Board
a.
The
Agency
requested
that
the
Board
provide
comment
on
the
following:
44
of
69
Whether
references
to
the
test
material
as
a
drug
and
other
statements
that
could
indicate
the
study
constituted
medical
research,
that
appear
in
the
materials
used
to
obtain
informed
consent
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;

Whether
the
administration
of
the
test
material
for
three
additional
days
without
monitoring
subjects'
cholinesterase
levels
following
the
detection
of
cholinesterase
inhibition
greater
than
20
%
in
some
subjects
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;
and
Whether
the
lack
of
medical
surveillance
of
subjects,
following
the
termination
of
dosing,
to
establish
the
subjects'
cholinesterase
levels
returned
to
normal
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;
and
b.
The
Agency
asked
that
the
Board
provide
comment
on
the
following,
taking
into
account
all
that
is
known
about
the
ethical
conduct
of
the
Gledhill
repeated
dose
study:

OPP's
conclusion
that
there
was
not
clear
and
convincing
evidence
that
the
conduct
of
the
research
was
fundamentally
unethical;
and
Whether
there
is
clear
and
convincing
evidence
that
the
conduct
of
the
Gledhill
repeat
dose
study
was
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

Board
Response
to
the
Charge
Brief
Overview
of
the
Study
As
noted
above,
the
study
was
conducted
in
1996
by
the
Zeneca
Central
Toxicology
Laboratory,
Cheshire,
United
Kingdom.
The
study
sponsor
was
the
Amvac
Chemical
Corporation.
The
protocol
documents
specifically
state
that
the
research
was
conducted
in
compliance
with
the
guideline
of
the
Declaration
of
Helsinki,
1964,
as
amended
through
1989.

Critique
of
Study
The
Board
concurred
with
the
Agency's
factual
observations
of
the
strengths
and
weaknesses
of
the
study,
as
detailed
in
Carley
(
2006e).
However,
further
comments
are
warranted
with
regard
to:
1)
whether
the
provisions
in
the
protocol
for
monitoring
the
subjects
adequately
protected
them,
and
2)
whether
the
documentation
and
process
of
study
subject
enrollment
was
sufficient
to
meet
prevailing
standards
of
voluntary
informed
consent.

1.
Monitoring
of
Subjects
While
Receiving
Study
Compound
The
protocol
permitted
subjects
to
continue
to
be
administered
the
study
compound
for
three
days
following
the
detection
of
RBC
cholinesterase
inhibition
of
greater
than
20%.
Given
45
of
69
that
study
subjects
were
not
monitored
during
most
of
the
study
(
and
were
not
full­
time
residents
at
the
study
laboratory),
it
was
possible
that
they
might
develop
clinically
significant
symptoms
during
this
period
and
no
one
would
be
available
to
detect
that
and
to
treat
them.
The
Board
concluded
that
this
aspect
of
the
study
design
was
inadequate.
However,
given
that
there
had
been
a
prior
similar
study
at
triple
the
dose
used
in
this
study,
and
that
study
had
demonstrated
minimal
symptoms,
the
Board
could
not
conclude
that
there
was
clear
and
convincing
evidence
that
this
element
of
the
study
design
could
have
resulted
in
serious
harm
based
on
the
knowledge
available
to
the
investigators
at
the
time.

2.
Monitoring
of
Subjects
at
End
of
Study
The
protocol
also
provided
that,
at
the
end
of
the
study,
inhibition
levels
would
not
be
retested
for
periods
as
long
as
seven
days
even
though
some
subjects
had
RBC
cholinesterase
inhibition
of
greater
than
20%.
During
this
period
of
time,
due
to
the
long­
acting
nature
of
the
study
compound,
subjects'
cholinesterase
inhibition
levels
could
have
been
increasing,
and
thus
symptoms
might
have
developed
and,
theoretically
have
become
serious
at
a
time
when
they
were
being
infrequently
monitored.
The
Board
determined
that
this
aspect
of
the
study
design
was
inadequate.
However,
as
noted
above,
given
that
there
had
been
a
prior
similar
study
at
triple
the
dose
used
in
this
study,
and
that
study
had
demonstrated
minimal
symptoms,
the
Board
could
not
conclude
that
there
was
clear
and
convincing
evidence
that
this
element
of
the
study
design
could
have
resulted
in
serious
harm
based
on
the
knowledge
available
to
the
investigators
at
the
time.

The
inadequate
monitoring
during
and
at
the
end
of
the
study
undermines
the
scientific
value
of
the
study.
The
fact
that
the
research
subjects
were
unsupervised
during
the
study,
and
the
ascertainment
of
adverse
event
data
was
through
self­
report,
renders
the
data
establishing
a
NOAEL
suspect.
The
risk
of
a
"
false
negative"
conclusion
is
quite
high.
In
addition,
the
failure
to
achieve
a
steady
state
in
the
inhibition
of
acetyl
cholinesterase
activity
may
render
these
data
inadequate
as
well,
and
of
limited
utility.
This
fact,
also
noted
in
the
Board's
scientific
review,
can
negatively
influence
the
prospective
benefit
to
risk
ratio.

3.
Informed
Consent
It
was
clear
that
the
written
documentation
for
informed
consent
failed
to
fully
meet
the
standards
outlined
of
the
1989
version
of
the
Declaration
of
Helsinki.

In
particular,
the
information
sheet
that
was
given
to
research
subjects
as
an
appendix
to
the
signed
informed
consent
document
under
the
subheading
Possible
Adverse
Events
noted
that
if
"
any
symptoms
possibly
due
to
enzyme
blocking
did
occur,
they
could
rapidly
be
reversed
by
a
specific
antidote."
Although
that
statement
is
a
correct
statement
of
the
scientific
issue,
it
failed
to
take
into
account
the
fact
that
this
study
did
not
involve
subjects
remaining
under
24
hour
supervision.
For
most
of
the
time,
the
subjects
would
not
be
under
any
supervision.
Given
that
enzyme
inhibition
could
build
up
over
time
due
to
the
long­
acting
nature
of
the
compound
being
studied,
symptoms
could
likely
occur
at
a
time
when
there
was
no
one
available
to
administer
the
antidote.
Telling
the
subjects
that
an
antidote
could
rapidly
reverse
symptoms
without
explaining
46
of
69
that
there
were
circumstances
in
which
that
antidote
would
not
be
readily
available
was
not
an
adequate
way
to
inform
subjects
of
the
true
nature
of
this
risk.

In
hindsight,
it
is
clear
that
the
documentation
provided
failed
to
rigorously
meet
the
standards
of
voluntary
informed
consent
applicable
to
studies
conducted
in
the
United
Kingdom
in
1996.
However,
there
was
not
clear
and
convincing
evidence
that
these
deficiencies
knowingly
and
seriously
impaired
the
informed
consent
process.

HSRB
Consensus
and
Rationale
The
Board
concluded
that:

a)
The
DDVP
repeat
dose
oral
human
toxicity
study
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted.

b)
There
was
no
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained.

c)
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted)
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

The
Board
determined
that
there
was
not
clear
and
convincing
evidence
that
references
to
the
test
material
as
a
drug
and
other
statements
that
could
indicate
the
study
constituted
medical
research,
that
appear
in
the
materials
used
to
obtain
informed
consent
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.
These
statements
are
highly
undesirable,
and
should
not
be
used
as
part
of
modern­
day
practice
in
writing
such
consent
materials.
Nonetheless,
it
was
unfortunately
not
uncommon
for
such
wording
to
have
been
used
in
consent
materials
in
the
past.
In
addition,
other
wording
in
the
consent
materials
clearly
advised
subjects
that
this
was
a
study
involving
consuming
an
insecticide.
The
Board,
however,
specifically
rejects
the
arguments
of
the
study
sponsor
that
it
was
appropriate
to
use
the
"
drug"
terminology
because
the
consent
materials
were
generic
materials
used
for
a
variety
of
studies.
It
also
rejects
the
study
sponsor's
argument
that
because
the
test
material
is
sometimes
used
as
a
drug,
it
was
appropriate
to
use
that
terminology
in
this
study
even
though
this
study
in
no
way
related
to
its
use
as
a
drug.

For
the
reasons
discussed
above,
the
Board
determined
that
there
was
not
clear
and
convincing
evidence
that
the
administration
of
the
test
material
for
three
additional
days
without
monitoring
subjects'
cholinesterase
levels
following
the
detection
of
cholinesterase
inhibition
greater
than
20
%
in
some
subjects
could
have
led
to
serious
harm.
There
the
study
should
not
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

For
the
reasons
discussed
above,
the
Board
determined
that
there
was
not
clear
and
convincing
evidence
that
following
the
termination
of
dosing,
the
lack
of
medical
surveillance
to
47
of
69
establish
the
subjects'
cholinesterase
levels
returned
to
normal
could
have
led
to
serious
harm.
Therefore
the
study
should
not
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

The
Board
concluded
that
the
Agency
can
rely
on
the
results
of
this
study,
as
appropriate
under
current
pesticide
laws,
given
the
absence
of
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical
or
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

6.
Ethephon
Charge
to
the
Board
Ethephon
is
an
organophosphorus
compound
that,
upon
absorption
into
plants,
forms
ethylene
gas
which
is
an
important
component
of
the
plant
hormone
complex.
The
Agency
is
conducting
an
aggregate
(
single
chemical,
multi­
route)
risk
assessment
of
ethephon.

Scientific
consideration
The
Agency's
WOE
document
and
DERs
for
ethephon
describe
the
study
design
and
results
of
the
ethephon
repeat
dose,
oral,
human
toxicity
studies.
The
WOE
document
also
discusses
the
Agency's
conclusions
regarding
the
usefulness
of
the
human
studies
in
the
aggregate,
single
chemical
risk
assessment.
The
Agency
has
concluded
that
the
28­
day
human
study
is
sufficiently
robust
to
establish
a
point
of
departure
for
extrapolating
acute
and
chronic
dietary
risk.

Please
comment
on
the
scientific
evidence
that
supports
this
conclusion.

Board
Response
to
the
Charge
Brief
Overview
of
the
Study
According
to
the
Agency's
weight
of
evidence
document
(
WOE)
(
Kent
2006)
,
"
ethephon
is
an
organophosphorus
compound
that,
upon
absorption
into
plants,
forms
ethylene
gas
which
is
an
important
component
of
the
plant
hormone
complex.
The
production
of
ethylene
by
plants
occurs
naturally
as
crops
mature
but
it
can
be
slow
during
periods
of
unfavorable
weather.
Ethylene
generated
from
ethephon
is
absorbed
by
the
plant
tissues
and
moderates
the
growth
process.
It
is
not
similar
in
structure
to
other
organophosphate
pesticides.
Ethephon
registrants
have
submitted
many
toxicity
studies
to
support
the
continued
pesticidal
use
of
the
chemical,
and
among
these
studies
are
two
involving
direct
dosing
of
human
subjects
that
OPP
is
considering
using
to
establish
endpoints
to
assess
risk
from
exposure
to
ethephon.
The
WOE
document
compares
the
strengths
and
weaknesses
of
the
human
and
animal
toxicity
studies
and
discusses
how
the
human
studies
fit
in
with
the
animal
studies,
i.
e.,
are
the
human
data
consistent
with
animal
data
in
terms
of
types
of
effects
and
effect
levels
or
are
there
notable
differences
between
animals
and
humans."
48
of
69
According
to
the
WOE
document,
"
as
a
strong
acid,
ethephon
is
corrosive
to
the
skin
and
eyes
(
Category
I).
In
acute
and
subchronic
neurotoxicity
studies
in
rats,
there
were
signs
of
neurotoxicity
at
doses
of
500
mg/
kg
and
above
(
acute)
and
300
mg/
kg
(
subchronic).
In
dogs
there
were
no
clinical
signs
of
neurotoxicity
evident
at
75
mg/
kg/
day
although
plasma
and
RBC
cholinesterase
were
inhibited
in
animals
at
doses
as
low
as
7.5
mg/
kg/
day."

There
were
two
human
studies
under
consideration,
both
involving
direct
dosing
of
human
subjects
and
are
repeated
dose
oral
studies,
one
for
28
days
duration
(
Reese
1972)
and
the
other
for
16
days
(
Weir
1977).

28
Day
Oral
Toxicity
Study
In
a
non­
guideline
oral
toxicity
human
study
(
Reese
1972),
ethephon
was
administered
by
capsule
in
a
powdered
formulation
(
10%
a.
i.
weight/
weight)
of
hydrated
silica
and
starch
to
human
adults
(
5/
sex)
at
an
average
dose
of
1.8
mg
a.
i./
kg/
day
or
placebo
0
mg/
kg/
day
(
3/
sex)
for
28
consecutive
days.
Administration
of
the
test
material
or
the
placebo
was
given
orally
by
capsule
divided
into
three
daily
doses.
Each
subject
received
2
capsules
postprandially
for
the
first
two
dosing
periods;
the
third
dose
was
given
at
the
end
of
the
work
day
in
order
to
simulate
as
closely
as
possible
ingestion
of
the
material
as
a
crop
residue.
The
capsules
were
dispensed
daily
(
5
days/
week)
by
an
assistant
who
observed
the
subjects
while
they
took
each
capsule
and
recorded
solicited
comments
related
to
the
ingestion
of
the
material
during
the
first
8
hours.
The
subjects
and
the
assistant
did
not
know
which
capsules
were
placebo
or
the
test
material.
Each
Friday,
the
subjects
received
a
supply
of
capsules
to
be
taken
during
the
two
day
weekend.
All
subjects
were
monitored
regularly
for
adverse
effects.
Hematology
measurements,
clinical
chemistry
and
urinalysis
were
conducted
initially
and
on
Days
7,
14,
21,
28
and
2
weeks
following
the
last
administration.
ChE
(
plasma
and
RBC)
determinations
were
conducted
using
the
 
pH/
hr
method
(
modified
Michel
method)
initially,
and
on
Days
1,
2,
7,
14,
28
and
2
weeks
after
the
last
administration.

Critique
of
28
Day
Oral
Toxicity
Study
MRID
00036510
The
ethephon
subjects,
though
exhibiting
normal
physical
appearance
and
behavior,
developed
symptoms
of
diarrhea
and
increased
urination
and
bowel
movement.
Three
females
and
one
male
experienced
a
sudden
onset
of
diarrhea
or
an
urgency
of
bowel
movement
of
1­
4
days
duration
during
the
first
week
of
the
compound
administration;
the
one
male
also
experienced
loose
stools
for
2
weeks.
Another
male
complained
of
stomach
cramps
or
gas
for
the
duration
of
the
study.
One
subject
in
the
ethephon
group
was
asymptomatic.
Five
subjects
experienced
increased
urgency
and
frequency
of
urination,
4
of
whom
experienced
this
symptom
throughout
the
study.
Two
subjects
experienced
decreased
appetite
while
a
third
(
with
diarrhea)
experienced
increased
appetite
during
the
first
2
days
of
the
study.
It
was
stated
that
the
symptoms
were
"
consistent
with
exposure
to
a
cholinesterase
inhibitor."
The
WOE
document
stated
"
the
clinical
signs
observed
in
the
study,
diarrhea
and
increased
frequency
of
urination,
are
consistent
with
a
cholinergic
mode
of
toxicity,
but
other
signs
associated
with
a
cholinesterase
inhibitor
such
as
pinpoint
pupils
(
miosis),
sweating,
runny
nose,
tearing,
salivation,
respiratory
distress
and
muscle
fasciculation
(
twitching),
were
not
seen
[
sic];
[
and]
the
test
subjects
reported
symptoms
as
they
considered
appropriate,
and
it
is
difficult
to
interpret
what
the
self­
reported
49
of
69
symptoms
mean
in
terms
of
a
biological
response."
In
fact,
it
is
unknown
if
symptoms
or
signs
associated
with
a
cholinesterase
inhibitor
were
seen;
they
may
not
have
been
monitored
or
specific
requests
for
their
reported
made
by
the
investigators.
However,
these
symptoms,
probably
related
to
irritant
effects,
are
important
results.

The
Agency's
Data
Evaluation
Record
(
Khasawinah)
and
the
WOE
documents
both
stated
"
None
of
the
placebo
subjects
had
similar
complaints."
This
was
probably
not
correct
since
according
to
the
investigators
at
least
two
of
these
controls
were
symptomatic
as
well
as
some
test
and
control
subjects
also
exhibited
some
atypical
lymphocytes
of
unknown
origin.

The
WOE
document
stated
"
Unexpectedly,
plasma
and
RBC
ChE
activities
were
similar
or
slightly
higher
than
initial
values
in
the
test
subjects.
([
The]
details
of
the
ChE
determinations
were
not
provided.)"
However,
the
ChE
levels
were
not
related
to
the
diarrhea
occurring
in
the
subjects
upon
examination
of
the
time
of
symptom
occurrence
and
ChE
data
provided.
The
WOE
document
states
"
No
compound
effects
regarding
hematology,
clinical
chemistries
and
urinalysis
were
reported",
except
the
atypical
lymphocytes
of
some.

It
was
concluded
by
the
investigators
of
this
study
that
the
daily
dose
of
1.8
mg/
kg/
day
is
the
LOAEL
for
the
oral
ingestion
of
ethephon
in
human
subjects.
However,
that
is
quite
uncertain
since
lower
doses
were
not
given.

16
Day
Oral
Toxicity
Study
In
the
other
non­
guideline
oral
toxicity
human
study
(
Weir
1977),
ethephon
was
administered
by
capsule
in
a
powdered
formulation
(
2.5%
a.
i.
weight/
weight)
of
hydrated
silica
and
starch
to
human
adults
(
10/
sex)
at
an
average
dose
of
0.5
mg
a.
i./
kg/
day
or
placebo
0
mg/
kg/
day
(
6
males
and
4
females)
for
16
consecutive
days
followed
by
a
29
day
recovery
period
(
phase
three).
The
dosing
phase
(
phase
two)
was
preceded
with
a
6
day
period
(
phase
one)
where
all
subjects
received
daily
placebos.
Administration
of
the
test
material
or
the
placebo
was
given
orally
by
capsule
divided
into
three
daily
doses.
Each
subject
received
two
capsules
postprandially
for
the
first
two
dosing
periods;
the
third
dose
was
given
at
the
end
of
the
work
day
in
order
to
simulate
as
closely
as
possible
ingestion
of
the
material
as
a
crop
residue.
The
capsules
were
dispensed
daily
(
5
days/
week)
by
an
assistant
who
observed
the
subjects
while
they
took
each
capsule
and
recorded
solicited
comments
related
to
the
ingestion
of
the
material
for
8
hours.
The
subjects
and
the
assistant
did
not
know
which
capsules
were
placebo
or
the
test
material
in
any
of
the
study
phases.
Each
Friday,
the
subjects
received
a
supply
of
capsules
to
be
taken
during
the
two
day
weekend.
All
subjects
were
monitored
regularly
for
adverse
effects.
Hematology
measurements
and
clinical
chemistry
were
conducted
on
blood
samples
collected
during
phases
I,
II
and
III
while
urinalysis
was
conducted
on
samples
collected
during
phase
II.
ChE
(
plasma
and
RBC)
determinations
were
conducted
using
the
 
pH/
hr
method
(
modified
Michel
method)
on
blood
collected
during
phases
I,
II,
and
III.

Critique
of
16
day
Oral
Toxicity
Study
No
clinical
symptoms
were
reported,
but
it
was
not
known
if
this
was
an
omission
as
the
report
did
not
state
that
there
were
no
symptoms
or
signs.
Hematological,
clinical
chemistry
50
of
69
values
and
urinalysis
parameters
were
comparable
to
the
placebo
controls.
The
updated
executive
summary
of
the
Agency
Data
Evaluation
Record
(
Khasawinah)
for
the
16­
day
human
study
stated:
"
Plasma
and
RBC
ChE
activities
were
significantly
inhibited
in
both
placebo
and
test
groups.
Therefore,
this
finding
makes
any
conclusions
regarding
the
effects
attributable
to
ethephon
administration
impossible.
This
is
in
contradiction
to
the
study
authors
overall
conclusion
that
a
daily
ethephon
oral
dosage
of
0.5
mg/
kg/
day
produces
significant
plasma
ChE
inhibition,
which
is
reversible
in
15
days."
The
study
report
stated
"
Plasma
cholinesterase
was
significantly
inhibited
for
the
placebo
group
at
4,
8,
12,
and
16
days
during
the
dosage
period.
In
the
test
group,
plasma
cholinesterase
was
also
depressed
(
greater
than
the
placebo
group)
at
4,
8,
12,
and
16
days
during
the
dosage
period.
Recovery
does
occur
as
indicated
by
the
15
and
29
post
dosage
values.
RBC
cholinesterase
inhibition
was
similar
for
both
placebo
and
test
groups
(
slightly
depressed
in
both
groups)
on
days
4,
12,
and
16
of
the
dosage
period
and
day
15
of
the
recovery
period."
Investigators
also
said
that
the
test
group
plasma
values
were
significantly
different
than
the
placebo
group
values.

It
appeared
that
either
the
method
of
testing
cholinesterase
was
poor,
or,
less
likely,
something
else
was
depressing
plasma
cholinesterase
in
this
latter
study
while
increasing
it
in
the
former
study.
Possibly,
as
the
ethephon
risk
assessment
team
concluded,
measures
of
blood
cholinesterase,
either
plasma
or
RBC,
were
not
appropriate
for
endpoint
selection
for
ethephon.

According
to
the
WOE
document
(
Kent
2006)
"
The
OPP/
HED
RfD
Peer
Review
Committee
determined
on
February
10,
1994
that
the
reference
dose
(
RfD)
should
be
based
on
the
28­
day
study
in
human
subjects
(
MRID
00036510).
Clinical
signs
of
toxicity
were
observed
at
1.8
mg/
kg/
day
(
only
dose
tested)
and
included
diarrhea,
urgency
of
bowel
movements,
urinary
urgency
and
stomach
cramps."

A
Report
from
EPA,
Office
of
Pesticide
Programs,
Health
Effects
Division,
Hazard
Identification
and
Assessment
Review
Committee
(
HIARC)
dated
4/
1/
98
stated
in
reference
to
the
28­
day
human
study:
"
This
human
study
is
considered
to
be
of
better
quality
and
the
findings
more
reliable
than
the
16­
day
human
study
previously
used
to
define
the
RfD."
Since
1994,
the
HIARC
has
repeatedly
(
8/
9/
94,
4/
1/
98,
7/
15/
02
and
11/
5/
02)
selected
the
28­
day
human
study
to
assess
all
relevant
exposure
scenarios,
and
at
the
last
HIARC
meeting,
a
weight
­
of
­
evidence
comment
regarding
endpoint
selection
was
included:
"
HIARC
had
considered
experimental
animal
studies
on
ethephon
and
concluded
this
human
study
was
most
appropriate
for
selection
of
the
endpoint
of
toxicity
for
risk
assessment.
The
clinical
signs
of
toxicity
in
this
human
study
occurred
at
dose
levels
that
were
much
lower
than
seen
in
experimental
animals."
"
Despite
the
limitations
of
the
study,
and
the
equivocal
nature
of
the
reported
findings,
the
HED
ethephon
risk
assessment
team
believes
that,
in
the
absence
of
data
ruling
out
the
observed
effects
as
inconsequential,
the
28­
day
human
study
is
the
most
appropriate
study
to
use
for
assessing
both
the
acute
and
chronic
dietary
risks
of
ethephon."

The
WOE
document
stated:
"
A
number
of
conclusions
relevant
to
endpoint
selection
can
be
drawn
from
the
database
of
ethephon
oral
toxicity
studies
in
humans
and
animals:
(
1)
ethephon
is
neurotoxic
in
animal
studies
only
at
high
doses
(
300
mg/
kg
and
above),
(
2)
ethephon
inhibits
blood
cholinesterases,
in
particular
plasma
cholinesterase
in
animals
and
humans
at
relatively
low
doses,
(
3)
brain
acetylcholinesterase
is
insensitive
to
ethephon
in
adult
51
of
69
animals.
Accordingly,
the
team
then
debated
whether
to
use
effects
in
animals
(
LOAEL
approximately
80
mg/
kg/
day)
or
in
humans
(
LOAEL
of
1.8
mg/
kg/
day)
for
endpoint
selection,
and
opted
as
a
matter
of
prudence
to
base
endpoint
selection
on
effects
observed
in
humans."
The
Board
concluded
that
this
was
much
lower
than
that
expected
from
the
animal
studies,
however,
the
second
study
informed
the
first
and
provided
the
level
of
uncertainty
to
accept
this
LOAEL
and
use
it
as
a
POD.

The
WOE
document
concluded
by
stating:
"
The
point
of
departure
for
the
dietary
assessments
use
of
a
LOAEL
was
applied
to
the
POD
to
obtain
a
reference
dose
of
0.06
mg/
kg/
day
for
assessment
of
both
acute
and
chronic
dietary
risks
(
1.8
mg/
kg/
day
(
with
an
uncertainty
factor
of
10x
for
intraspecies
variability
and
a
3x
factor
for
use
of
a
LOAEL
 )"

HSRB
Consensus
and
Rationale
The
Board
concluded
that
the
scientific
quality
of
either
the
ethephon
28
day
oral
toxicity
study
or
the
ethephon
16
day
human
oral
toxicity
study
was
not
adequate
on
its
own.
The
16
day
study
can
be
used
to
inform
the
ethephon
28
day
human
oral
toxicity
study.
The
Board
approved
the
28
day
study
for
use
in
EPA
risk
assessments,
emphasizing
that
the
dose
level
administered
was
almost
certainly
not
the
lowest
dose
at
which
adverse
effects
are
likely
to
be
observed.
However,
its
use
in
lieu
of
the
animal
studies
would
result
in
greater
protection
for
exposed
human
populations.

6.2.
Ethical
considerations
Charge
to
the
Board
In
its
ethics
review
of
this
research,
EPA
documented
that
the
study
reports
contained
very
little
information
concerning
the
ethical
conduct
of
the
research
and
that
the
available
information
raised
no
ethical
concerns.
The
Agency
asked
that
the
Board
provide
comment
on
the
following,
taking
into
account
all
that
is
known
about
the
ethical
conduct
of
each
study:

OPP's
conclusion
that
there
was
not
clear
and
convincing
evidence
that
the
conduct
of
the
research
was
fundamentally
unethical;
and
whether
there
is
clear
and
convincing
evidence
that
the
conduct
of
the
study
was
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

Board
Response
to
the
Charge
Brief
Overview
of
the
Study
Two
studies
involving
repeat
high­
and
low­
dose
oral
exposure
of
human
subjects
to
ethephon
(
ethrel)
were
evaluated.
Both
studies
were
performed
by
Litton
Bionetics,
Inc.
of
Bethesda,
Maryland.
The
studies
were
sponsored
by
Amchem
Products,
Inc.,
of
Ambler,
Pennsylvania.
Both
studies
were
conducted
prior
to
publication
of
U.
S.
regulations
(
drafted
1974,
adopted
by
DHHS
and
FDA
in
1981)
or
the
Common
Rule
(
adopted
by
EPA
in
1991),
so
52
of
69
the
regulatory
standards
established
by
45
CFR
46
with
respect
to
conduct
of
research
involving
human
subjects
cannot
be
applied
in
this
retrospective
evaluation.
The
low­
dose
study,
however,
was
performed
after
the
1972
Federal
Insecticide,
Fungicide,
and
Rodenticide
Act
(
FIFRA)
went
into
effect,
and
is
subject
to
the
regulations
contained
therein.
In
particular,
FIFRA
Section
12(
a)(
2)(
P)
states
that
"[
i]
t
shall
be
unlawful
for
any
person
 
to
use
any
pesticide
in
tests
on
human
beings
unless
such
human
beings
(
i)
are
fully
informed
of
the
nature
and
purposes
of
the
test
and
of
any
physical
and
mental
health
consequences
which
are
reasonably
foreseeable
therefrom,
and
(
ii)
freely
volunteer
to
participate
in
the
test."
Both
studies
were
also
are
expected
to
be
in
compliance
with
the
ethical
standards
for
research
involving
human
subjects
established
by
the
1964
version
of
the
Declaration
of
Helsinki.

Critique
of
Study
The
Board
concurred
with
the
factual
observations
of
the
strengths
and
weaknesses
of
the
study,
as
detailed
in
Carley
(
2006f,
g).
However,
further
comments
are
warranted
regarding:
1)
whether
the
repeat
high­
dose
oral­
exposure
protocols
used
were
designed
to
minimize
risks
to
study
participants;
and
2)
whether
the
documentation
and
process
of
study
subject
enrollment
was
sufficient
to
meet
prevailing
standards
of
voluntary
informed
consent.

1)
Minimization
of
Risks
to
Study
Participants
The
two
repeat
high­
and
low­
dose
oral­
exposure
studies
were
performed
in
1971
and
1973,
respectively.
The
high­
dose
study
involved
repeated
dosing,
over
a
28­
day
period,
of
12
subjects
(
six
men
and
six
women)
with
1.8
mg/
kg
body
weight
of
ethephon
per
day
by
oral
ingestion.
Four
subjects
(
two
men
and
two
women)
received
placebo
control.
The
study
documents
provided
no
clear
justification
for
the
selection
of
the
1.8
mg/
kg
body
weight
dose,
other
than
passing
reference
to
"
a
preliminary
dose
range
study
 
carried
out
in
two
human
subjects.
(
Litton
1972).

On
weekdays,
clinical
symptoms
were
monitored
continuously
for
eight
hours
following
ingestion
of
the
test
compound;
after
hours
and
on
weekends,
subjects
were
requested
to
selfreport
any
adverse
clinical
symptoms.
There
was
no
mention
in
the
documents
reviewed
by
the
Board
that
the
investigators
made
provisions
for
observation
or
rescue
during
these
off
hours.
Laboratory
analyses,
including
analysis
of
blood
and
urine
samples,
were
performed
weekly
during
the
study
and
also
two
weeks
after
last
exposure.
A
large
number
of
study
subjects
receiving
the
active
compound
exhibited
clinical
symptoms
clearly
associated
with
ethephonexposure
including
diarrhea
and
other
gastrointestinal
disorders
(
4
participants),
increased
frequency
and
urgency
of
urination
(
5
participants),
and
persistent
abdominal
pain
(
1
participant).
Laboratory
analyses
also
revealed
transient
elevations
in
blood
glucose
and
increased
inhibition
of
plasma
cholinesterase
in
subjects
receiving
ethephon.
No
stopping
criteria
were
listed
in
the
final
report,
nor
were
there
evidence
that
the
investigators
considered
halting
the
trial
even
after
large
numbers
of
study
participants
began
to
report
adverse
clinical
symptoms.

The
low­
dose
study
involved
repeated
dosing,
over
a
16­
day
period,
of
20
subjects
(
10
men
and
10
women)
with
0.5
mg/
kg
body
weight
of
ethephon
per
day
by
oral
ingestion.
Ten
53
of
69
subjects
(
six
men
and
four
women)
received
placebo
control.
The
study
documents
again
provide
no
clear
justification
for
the
selection
of
the
0.5
mg/
kg
body
weight
dose,
other
than
indirect
reference
to
the
high­
dose
study
described
above.

As
before,
clinical
symptoms
were
monitored
continuously
for
eight
hours
and
selfreported
after
hours
and
on
weekends.
Laboratory
analyses
were
performed
on
days
1,
9,
and
16,
and
two
weeks
following
last
dose.
Surprisingly,
the
report
failed
to
mention
that
no
adverse
clinical
events
were
seen,
leading
several
Board
members
to
suspect
that
adverse
event
data
was
not
rigorously
collected.

2)
Voluntary
Informed
Consent
Neither
study
contained
sufficient
information
for
the
Board
to
adequately
determine
whether
or
not
the
informed
consent
process
used
to
enroll
study
participants
met
the
standards
outlined
in
FIFRA
Section
12(
a)(
2)(
P)
and
the
1964
version
of
the
Declaration
of
Helsinki.
Each
of
the
final
study
reports
provided
to
the
Board
contained
only
but
the
briefest
of
statement
as
to
the
nature
of
the
voluntary
informed
consent
process:

"
Sixteen
human
volunteers
judged
to
be
in
good
health
as
ascertained
by
pre­
physical
interview,
physical
examination
and
selected
clinical
laboratory
evaluations
were
chosen
for
the
study.
All
subjects
were
thoroughly
briefed
on
the
nature
and
present
use
of
the
test
product,
the
animal
toxicity
data,
and
the
potential
pharmacological
side
effects."

"
All
subjects
were
thoroughly
informed
on
the
nature
and
present
use
of
the
test
substance,
the
animal
toxicity
data,
potential
pharmacologic
side
effects,
and
the
results
of
the
prior
study
in
human
volunteers.
Based
on
this
briefing,
consent
documents
were
obtained
from
all
subjects."

Although
the
1973
low­
dose
study
does
contain
reference
to
written
consent
documents,
these
were
unavailable
for
review.

Despite
the
paucity
of
documentation,
several
Board
members
expressed
concern
over
what
they
consider
to
be
potential
violations
of
accepted
standards
of
informed
consent:

 
Circumstantial
evidence
suggests
that
employees
of
Litton
Bionetics,
Inc.,
may
have
been
enrolled
as
study
participants.
For
example,
there
was
mention
of
four
study
participants
"
working
in
the
same
building."
The
possible
participation
of
employees
in
a
laboratory­
directed
research
project
raised
issues
of
coercion
and
voluntariness.
 
In
the
high­
dose
study,
a
large
number
of
study
subjects
receiving
active
compound
exhibited
clinical
symptoms
clearly
associated
with
ethephonexposure
including
diarrhea
and
other
gastrointestinal
disorders,
increased
frequency
and
urgency
of
urination,
and
persistent
abdominal
pain.
Not
a
single
study
participant,
however,
withdrew
from
the
study
over
the
28­
day
monitoring
period,
regardless
of
the
severity
of
illness.
This
again
raised
questions
about
the
voluntary
nature
of
participation
in
research.
54
of
69
HSRB
Consensus
and
Rationale
The
Board
concluded
that:

a)
Both
the
28
and
16
day
oral
human
toxicity
studies
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted.

b)
There
were
no
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained.

c)
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted),
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

Although
these
two
studies
appear
to
lack
justification
for
the
dose
selection,
as
well
as
clear
stopping
criteria
to
prevent
serious
harm
to
research
participants,
the
Board
did
not
believe
that
there
was
clear
and
convincing
evidence
that
these
studies
could
have
resulted
in
serious
harm
based
on
the
knowledge
available
to
the
investigators
at
the
time.

There
were
indications
of
informed
consent
deficiencies.
Nevertheless,
given
the
paucity
of
information
provided
there
was
no
evidence
that
the
voluntary
informed
consent
process
used
in
these
two
studies
failed
to
meet
the
few
regulatory
and
ethical
standards
applicable
to
research
conducted
in
1971­
1973.

The
Board
concluded
that
there
was
no
obvious
reason
why
the
Agency
cannot
rely
on
the
results
of
this
study,
as
appropriate
under
current
pesticide
laws,
given
the
absence
of
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical
or
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

7.
Sodium
Cyanide
Charge
to
the
Board
When
sodium
cyanide
is
used
as
a
fumigant,
hydrogen
cyanide
is
generated
by
acidification.
Because
residues
of
HCN
may
remain
on
fumigated
citrus,
the
Agency
is
conducting
an
acute
dietary
risk
assessment
of
hydrogen
cyanide.

7.1.
Scientific
considerations
The
Agency's
WOE
document
describes
a
lack
of
data
appropriate
for
developing
an
acute
dietary
risk
assessment
for
hydrogen
cyanide.
The
WOE
and
DER
present
the
results
from
a
clinical
trial
with
amygdalin
and
the
usefulness
of
this
clinical
trial
in
the
acute
dietary
risk
assessment
for
hydrogen
cyanide.
The
Agency
had
concluded
that
the
clinical
trial
was
55
of
69
appropriate
for
establishing
a
point
of
departure
in
the
acute
dietary
risk
assessment
for
hydrogen
cyanide.

Please
comment
on
the
scientific
evidence
that
supports
this
conclusion.

Board
Response
to
the
Charge
Brief
Overview
of
the
Study
The
clinical
trial
of
amygdalin
for
treatment
of
cancer
(
Moertel
et
al.,
1982),
which
included
the
preliminary
pharmacology
and
toxicology
study
(
Moertel
et
al.,
1981),
involved
the
administration,
under
controlled
circumstances,
of
known
amounts
of
amygdalin
to
patients
with
terminal
cancers
for
which
no
known
treatments
were
available.
Amygdalin
was
administered
intravenously
for
21
days
(
4.5
g/
m2),
followed
by
oral
maintenance
therapy
of
500
mg
(
three
times
per
day),
plus
a
"
metabolic
therapy"
consisting
of
diet,
pancreatic
enzymes,
and
vitamins.
Most
patients
were
administered
the
standard
dose
regimen,
but
a
small
number
received
a
high
dose
regimen.

Clinical
signs
and
symptoms
consistent
with
cyanide
toxicity
(
nausea,
vomiting,
headache,
dizziness,
mental
obtundation)
were
observed
in
some
patients
following
a
single
500
mg
oral
dose
of
amygdalin.
The
conclusions
regarding
toxicity
were
based
largely
on
several
patients
who
developed
such
symptoms
when
they
took
two
500
mg
doses
too
close
together
or
ate
foods
such
as
raw
almonds
that
are
rich
in
ß­
glucosidase,
an
enzyme
that
causes
the
release
of
cyanide
from
amygdalin.
In
such
patients,
the
symptoms
typically
resolved
when
oral
amygdalin
was
discontinued,
the
dose
was
reduced,
or
the
patients
stopped
eating
the
critical
foods.
In
the
pharmacology
and
toxicology
study,
the
responses
of
two
patients
challenged
with
almonds
provided
further
support
for
the
conclusion
that
the
symptoms
reflected
cyanide
toxicity.
In
some
patients,
the
appearance
of
symptoms
was
associated
with
relatively
high
blood
cyanide
levels,
which
in
some
instances
approached
levels
observed
in
human
fatalities
(>
3
µ
g/
mL).
A
dose
of
500
mg
was
interpreted
as
a
minimal
effect
level
but
not
as
a
NOAEL.

Critique
of
Study
The
trial
had
several
strengths.
The
sample
size
was
large,
including
178
patients.
Bloodcyanide
levels
were
assessed
several
times,
at
completion
of
intravenous
(
i.
v.)
treatment,
48
hours
after
initiation
of
oral
treatment,
and
at
every
subsequent
evaluation.
Measurements
were
made
two
hours
after
the
first
morning
dose
of
oral
amygdalin,
when
the
maximum
elevation
in
cyanide
was
anticipated.
The
trial
employed
a
good
operational
definition
of
the
clinical
outcome
of
interest
in
the
trial,
which
was
tumor
progression.

The
trial
also
had
several
weaknesses.
First,
it
was
not
blinded
and
did
not
include
a
placebo
group.
Second,
insofar
as
the
primary
aim
was
to
assess
the
effectiveness
of
amygdalin
as
a
treatment
for
advanced
cancer,
the
assessment
of
potential
cyanide
toxicities
was
not
as
systematic
as
the
assessment
of
tumor
progression.
As
in
any
clinical
trial
of
drug
efficacy,
side
effects
were
recorded,
however,
these
side
effects
were
examined
in
relation
to
whole­
blood
cyanide
levels.
Oral
dosing
with
amygdalin
did
not
begin
until
21
days
of
i.
v.
treatment
had
been
56
of
69
completed.
It
is
unlikely
that
this
introduced
a
bias,
however.
In
contrast
to
delivery
by
oral
route,
amygdalin
delivered
i.
v.
is
largely
excreted
unchanged
in
urine
without
conversion
to
cyanide.
Whole
blood
cyanide
levels
were
undetectable
following
i.
v.
dosing,
making
it
likely
that
the
rise
observed
following
oral
dosing
was
not
confounded
by
the
prior
i.
v.
dosing.
Third,
patients
who
participated
in
the
study
were
terminally
ill
with
cancer.
Although
the
inclusion
criteria
required
that
patients
be
in
"
good
general
condition"
and
ambulatory,
they
are,
nevertheless,
likely
to
represent
a
particularly
sensitive
subgroup,
thus
providing
a
conservative
estimate
of
the
hydrogen
cyanide
dose
at
which
toxicities
occur.
Fourth,
all
clinical
signs
and
symptoms
of
toxicity
(
nausea,
vomiting,
headache,
dizziness,
mental
obtundation,
and
dermatitis)
were
observed
with
nearly
equivalent
frequencies
during
i.
v.
and
oral
dosing.
Many
of
these
signs
and
symptoms
might
be
increased
in
terminal
cancer
patients
anyway,
and
thus
unrelated
to
amygdalin
or
cyanide.
Moreover,
if
these
were
indications
of
toxicity
related
solely
to
elevations
in
blood
cyanide,
they
would
not
be
expected
to
have
occurred
with
equal
frequency
during
i.
v.
and
oral
dosing.
The
data
from
the
natural
experiments
within
the
trial,
such
as
when
the
doses
of
individual
patients
who
developed
symptoms
were
changed
or
the
patients
were
challenged,
provides
the
most
persuasive
evidence
of
an
increased
risk
of
cyanide
toxicity
in
patients
administered
amygdalin.

HSRB
Consensus
and
Rationale
The
Board
concluded
that
data
from
the
amygdalin
trial
could
be
used
for
establishing
a
point
of
departure
in
the
acute
dietary
risk
assessment
for
sodium
cyanide.

Despite
its
limitations,
this
study
provides
the
best
data
we
are
likely
to
ever
have
on
which
to
establish
a
POD
for
this
purpose.
Given
the
severity
of
the
effect,
the
steepness
of
the
dose­
response
relationship,
and
the
apparent
inter­
individual
differences
in
response
to
a
given
dose,
it
would
be
imprudent
to
undertake
an
intentional
dosing
study
of
healthy
humans
in
order
to
establish
a
LOAEL
and
NOAEL
for
hydrogen
cyanide.

7.2
Ethical
considerations
Charge
to
the
Board
In
its
ethics
review
of
this
research,
EPA
did
not
identify
any
deficiencies
with
respect
to
the
ethical
conduct
of
this
research.
The
Agency
asked
that
the
Board
provide
comment
on
the
following,
taking
into
account
all
that
is
known
about
the
ethical
conduct
of
this
study:

OPP's
conclusion
that
there
was
not
clear
and
convincing
evidence
that
the
conduct
of
the
research
was
fundamentally
unethical;
and
whether
there
was
clear
and
convincing
evidence
that
the
conduct
of
the
study
was
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

Board
Response
to
the
Charge
Brief
Overview
of
the
Study
57
of
69
Two
related
studies
were
being
evaluated.
Both
were
sponsored
by
the
National
Cancer
Institute.
The
first
study
was
a
pharmacologic
and
toxicological
study
involving
six
subjects
which
took
place
at
the
Mayo
Clinic
(
Rochester,
MN),
with
the
results
being
published
in
the
Journal
of
the
American
Medical
Association
in
1981
(
the
Board
assumed
the
study
was
conducted
1979­
1980).
Although
the
published
report
does
not
describe
the
ethical
standards
to
which
the
researchers
adhered,
the
Board
assumed
that
as
a
federally­
funded
study,
the
research
would
have
been
subject
to
the
then­
current
version
of
the
federal
DHHS
[
DHEW]
regulations
(
45
CFR
Part
46)
that
would
later
become
the
Common
Rule.
The
second
study
was
essentially
a
Phase
II
follow­
up
to
the
first
study,
involving
178
subjects
who
were
enrolled
at
four
sites
(
Mayo
Comprehensive
Cancer
Center,
Mayo
Clinic,
Rochester,
MN;
UCLA
Johnson
Comprehensive
Cancer
Center,
Los
Angeles,
CA;
Memorial
Sloan­
Kettering
Cancer
Center,
New
York,
NY;
and
University
of
Arizona
Cancer
Center,
Tucson,
AZ).
The
results
of
that
second
study
were
published
in
the
New
England
Journal
of
Medicine
in
1982.
That
article
also
did
not
specify
the
specific
ethical
rules
under
which
the
study
was
conducted,
and
this
Board
again
assumes
that
it
would
have
been
subject
to
the
then­
current
version
of
the
predecessor
regulations
(
DHHS
[
DHEW],
45
CFR
Part
46)
to
the
current
Common
Rule.

Critique
of
Study
The
Board
concurred
with
the
factual
observations
about
the
study,
as
detailed
in
Carley
(
2006h).

In
particular,
the
Board
concurred
with
the
key
observation
regarding
the
difference
between
this
study
and
the
other
studies
that
the
Board
has
heretofore
been
asked
to
review.
This
study
involved
testing
a
compound
for
its
safety
and
efficacy
in
treating
a
medical
problem.
As
such,
the
ethical
evaluation
of
this
study
was
significantly
different
from
that
of
a
study
involving
exposing
subjects
to
a
pesticide.
A
major
consideration
in
evaluating
the
ethics
of
such
a
study
involved
determining
whether
the
two
arms
of
the
study
were
in
clinical
equipoise,
a
concept
that
was
only
in
its
earliest
stages
at
the
time
of
this
study.
Nonetheless,
it
does
appear
that
this
study
would
meet
even
the
modern­
day
understanding
of
that
concept.
All
of
the
subjects
were
persons
with
histologically­
proven
cancer
for
which
no
standard
treatment
was
known
to
be
available.
The
subjects
received
either
a
standard
dose
or
a
high
dose
of
amygdalin
(
Laetrile).
Prior
to
this
study
being
conducted,
there
was
substantial
uncertainty
regarding
whether
this
compound
might
indeed
be
a
safe
and
effective
treatment
for
many
forms
of
cancer.
As
stated
in
the
New
England
Journal
of
Medicine
article,
it
had
"
eclipsed
any
other
unorthodox
therapy
ever
used
for
any
disease
in
our
time."
Thus,
conducting
this
study
served
to
answer
an
important
medical
question
of
that
time
period.

Moreover,
the
published
report
of
the
second
study
indicated
compliance
with
all
of
the
procedural
protections
that
would
be
required
today.
It
notes
that
all
"
patients
were
fully
informed
about
the
experimental
and
unorthodox
nature
of
the
treatment
program
as
well
as
any
possible
alternative
treatment
available
to
them.
A
signed
form
giving
informed
consent,
approved
by
the
Human
Subjects
Committee
at
each
of
the
four
participating
centers,
was
obtained
from
each
patient."
(
The
actual
forms
were
not
available
for
review
by
the
Board.)
The
article
further
noted
that
"
the
methods
of
this
trial
were
entirely
comparable
to
those
employed
in
58
of
69
studies
of
any
new
agent
being
developed
and
tested
for
cancer
treatment
through
more
traditional
channels."

HSRB
Consensus
and
Rationale
The
Board
concluded
that:
a)
The
sodium
cyanide
human
oral
toxicity
study
appeared
to
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted.

b)
There
was
no
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained.

c)
There
was
no
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted)
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

Although
the
Board
based
its
determinations
only
on
the
two
published
articles,
it
did
not
find
any
ethical
flaws
in
the
conduct
of
these
two
studies.
The
article
described
appropriate
informed
consent
procedures.
The
risks
and
potential
benefits
of
the
dosing
were
appropriate
for
a
medical
treatment
study
for
this
particular
cancer
population.

The
Board
concluded
that
there
was
no
obvious
reason
why
the
Agency
cannot
rely
on
the
results
of
this
study,
as
appropriate
under
current
pesticide
laws,
given
the
absence
of
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical
or
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

8.
Amitraz
Charge
to
the
Board
Exposure
to
amitraz
can
result
in
neurotoxicity
as
evidenced
by
clinical
signs
such
as
ataxia,
ptosis,
emesis,
labored
respiration,
muscular
weakness,
tremors,
hypothermia
and
bradycardia.
The
Agency
is
conducting
an
aggregate
(
single
chemical,
multi­
route)
risk
assessment
of
amitraz.

8.1.
Scientific
considerations
The
Agency's
WOE
document
and
DERs
for
amitraz
describe
the
study
design
and
results
of
the
amitraz
acute
oral
and
dermal
toxicity
human
studies
and
the
human
metabolism
study.
The
WOE
document
also
discusses
the
Agency's
conclusions
regarding
the
usefulness
of
the
human
studies
in
the
single
chemical
risk
assessment
for
acute
and
chronic
oral
exposures
in
addition
to
dermal
and
inhalation
exposures
of
various
durations.
For
oral
exposure,
the
Agency
had
concluded
that
the
combined
results
from
the
single
oral
dose
study
and
human
metabolism
study
established
a
dose
response
relationship
in
human
subjects
and
that
the
single
oral
dose
study
was
appropriate
for
developing
a
point
of
departure
for
acute
and
chronic
dietary
risk,
59
of
69
short­
term
oral
exposure,
and
inhalation
exposures
of
various
durations.
The
Agency
had
further
concluded
that
the
human
dermal
study
was
appropriate
for
developing
a
point
of
departure
for
dermal
exposures
of
various
durations.

Please
comment
on
the
scientific
evidence
that
supports
these
conclusions.

Board
Response
to
the
Charge
Overview
The
HSRB
was
asked
to
comment
on
the
scientific
evidence
that
supports
the
following
conclusions:

1.
For
oral
exposure,
the
Agency
concluded
that
the
combined
results
from
the
single
oral
dose
study
and
human
metabolism
study
established
a
dose­
response
relationship
in
human
subjects,
and
that
the
single
oral
dose
study
was
appropriate
for
developing
a
point
of
departure
for
acute
and
chronic
dietary
risk,
short­
term
oral
exposure,
and
inhalation
exposures
of
various
durations.

2.
The
Agency
further
concluded
that
the
human
dermal
study
is
appropriate
for
developing
a
point
of
departure
for
dermal
exposures
of
various
durations.

Amitraz
[
N'­(
2,4­
dimethylphenyl)­
N­[[(
2,4­
dimethylphenyl)
imino]
methyl]­
Nmethylmethanimidamide
is
an
insecticide/
acaricide
with
wide
range
of
registered
uses
in
the
United
States.
The
toxicity
profile
for
amitraz
has
not
been
characterized
completely,
especially
developmental
and
reproductive
effects.
Neurotoxicity
is
considered
the
most
sensitive
effect
resulting
from
exposure
to
amitraz.
Neurotoxicity
has
been
demonstrated
in
multiple
species
(
baboon,
cat,
dog,
mouse,
rat
and
rabbit).
Clinical
signs
include
central
nervous
system
depression,
ataxia
(
loss
of
coordination),
ptosis
(
droopy
eyelids),
emesis
(
vomiting),
labored
respiration,
muscular
weakness,
tremors,
hypothermia
and
bradycardia
(
slow
heartbeat).
Similar
signs
are
seen
in
humans.
The
Agency's
evaluation
of
amitraz
included
three
human
studies:
a
1984
oral
dose
metabolism
study
(
Campbell
1984),
a
1992
oral
dose
tolerance
study
(
Cass
1992)
and
a
1997
dermal
dose
tolerance
study
(
Langford
1997).

Critique
of
Oral
Dose
Metabolism
Study
(
1984)

Radio­
labeled
amitraz
was
orally
administered
to
rats,
mice,
baboons
and
humans.
The
two
human
volunteers
received
a
single
0.25
mg/
kg
dose
of
amitraz
by
capsule.
This
dose
caused
dry
mouth,
drowsiness,
disorientation,
decreased
temperature,
bradycardia,
and
slightly
pale
appearance
in
both
subjects,
persisting
up
to
12
hours
after
dosing.
One
subject
fell
asleep
for
6
hours
following
dosing.
Psychomotor
testing
was
not
included
in
the
protocol.
Approximately
44%
of
the
dose
was
excreted
within
12
hours,
with
63%
excreted
within
24
hours.
Study
deficiencies
included
the
small
number
of
subjects
(
N=
2),
testing
of
males
only,
and
no
control
group.
Sex
differences
in
the
repeat
dose
animal
studies
have
shown
that
females
were
more
sensitive
than
males.
The
study
investigators
concluded
that
humans
were
more
sensitive
to
amitraz
than
were
other
species
included
in
the
metabolism
study.
60
of
69
The
occurrence
of
multiple
signs
and
symptoms
in
both
subjects
and
the
continued
bradycardia
up
to
12
hours
post­
dosing
suggest
that
the
0.25
mg/
kg
dose
was
not
the
lowest
adverse
effect
level
for
amitraz
in
humans.
Because
there
was
only
one
dose
level,
it
was
not
possible
to
glean
any
information
regarding
dose­
response
from
this
study.
Incomplete
excretion
of
the
amitraz
metabolites
at
24
hours
post­
dosing
suggests
that
some
portion
of
the
dose
was
present
on
the
day
following
dosing,
albeit
not
at
levels
sufficient
to
produce
the
frank
signs
and
symptoms
observed
on
the
day
of
dosing.

Critique
of
Single
Oral
Dose
Study
(
1992)

The
design
was
a
single
oral
dose
double­
blind
tolerance
study.
The
primary
objective
of
this
study
was
to
determine
the
tolerance
of
male
volunteers
to
a
single
dose
of
amitraz
at
two
different
dose
levels
(
0.0625
and
0.125
mg/
kg),
with
a
placebo
control.
Six
subjects
completed
the
study.
Each
subject
received
each
of
the
doses
and
the
placebo.
Dosing
events
were
separated
by
at
least
14
days
for
each
subject.
The
dosing
regimen
was
thoughtfully
constructed,
beginning
with
the
lower
dose,
and
moving
to
the
higher
dose
when
it
was
observed
that
the
lower
dose
was
well
tolerated.
The
subjects
were
admitted
to
a
clinical
pharmacology
unit
the
evening
before
each
dosing
and
remained
there
for
36
hours.
Complete
physical
examinations
were
conducted
before
and
after
the
study.
The
subjects
were
followed
for
at
least
three
weeks
following
the
study.
The
most
sensitive
neurologic
endpoints
measured
in
this
study
were
two
psychomotor
performance
tests:
choice
reaction
time
and
critical
flicker
fusion
threshold.
The
psychomotor
performance
tests
were
administered
pre­
dose,
2.5
hours,
and
8
hours
following
dosing.
The
report
provides
tabular
and
graphic
representation
of
the
results
of
these
tests,
but
no
statistical
analyses
were
conducted.
Study
deficiencies
included
the
small
number
of
subjects
(
N=
6),
and
the
testing
of
males
only.
The
study
investigators
concluded
that
no
effects
were
observed
from
the
single
oral
dose
in
any
of
the
subjects.

The
major
concern
with
this
study
was
whether
"
no
effect"
was
truly
observed.
The
study
report
was
deficient
in
its
description
of
the
psychomotor
performance
testing,
and
in
the
rationale
for
selecting
these
tests.
There
were
no
descriptions
of
the
specific
procedures
followed
for
the
psychomotor
tests,
no
standard
operating
procedures,
and
no
quality
assurance
documentation.
Also,
there
was
no
evidence
provided
in
the
report
to
indicate
that
these
tests
were
the
most
sensitive
available.
A
review
of
the
current
scientific
literature,
and
discussions
with
leading
scientists
in
this
area
of
expertise
would
permit
the
Agency
to
determine
if
these
psychomotor
test
results
were
adequate
to
characterize
a
"
no
effect"
level
in
regard
to
neurotoxicity
for
amitraz.

Critique
of
Dermal
Toxicity
Study
(
1997)

This
study
was
a
double­
blind
sequential
dosing
study
with
a
randomized
crossover
and
a
placebo
group.
The
study
aims
were
to
1)
establish
a
no
effect
level
for
acute
effects
following
repeated
dermal
doses
of
amitraz
and
2)
produce
data
that
would
permit
calculation
of
margins
of
safety
for
agricultural
workers.
Eight
male
volunteers
were
given
a
total
dose
of
either
0,
8,
16
or
24
mg/
kg
amitraz,
applied
dermally
as
four
equal
doses
of
0,
2,
4
or
6
mg/
kg
in
an
aqueous
1:
1
(
w/
w)
slurry
every
2.5
hours
over
10
hours.
Starch,
1:
1
(
w/
w)
in
water,
was
used
as
a
61
of
69
placebo.
Each
of
these
amitraz
experiments
involved
a
timed
series
of
dosing
events
(
0,
2.5,
5.0,
and
7.5
hours),
followed
by
a
washing
event
at
10
hours.
Each
dose
within
an
experiment
was
applied
to
a
different
20
cm2
skin
surface
area,
so
the
total
skin
surface
treated
in
each
experiment
was
80
cm2.
Thus,
skin
loadings
for
the
three
experiments
were
7,000,
14,000,
and
21,000
µ
g/
cm2,
corresponding
to
the
three
dose
levels
(
8
mg/
kg,
16
mg/
kg,
24
mg/
kg),
assuming
a
body
weight
of
70
kg.
No
differences
were
observed
between
treatment
and
placebo
for
any
of
the
measured
endpoints.
No
urinary
metabolite
monitoring
was
conducted
to
confirm
that
amitraz
had
been
absorbed.
The
study
report
was
deficient
in
its
description
of
the
psychomotor
performance
testing,
and
in
the
rationale
for
selecting
these
tests.
There
was
no
description
of
the
specific
procedures
followed,
no
standard
operating
procedures,
and
no
quality
assurance
documentation.
Also,
there
was
no
evidence
provided
in
the
report
to
indicate
that
these
tests
were
the
most
sensitive
available.
A
review
of
the
current
scientific
literature,
and
discussions
with
leading
scientists
in
this
area
of
expertise
would
permit
the
Agency
to
determine
if
these
psychomotor
test
results
were
adequate
to
characterize
a
"
no
effect"
level
in
regard
to
neurotoxicity
for
amitraz.

The
primary
deficiency
of
this
study
was
that
it
did
not
provide
a
realistic
worker
exposure
scenario;
that
is,
the
exposures
of
the
subjects
in
these
experiments
did
not
correspond
to
exposures
likely
to
be
seen
among
workers.
Large
amounts
of
amitraz
(
140­
420
mg)
were
applied
to
a
relatively
small
skin
surface
area
(
80
cm2)
in
the
experiments,
whereas
we
typically
see
much
larger
skin
surface
areas
exposed
to
smaller
amounts
among
workers.
For
example,
the
hands,
a
skin
surface
commonly
exposed
to
pesticides,
have
a
total
surface
area
of
990
cm2,
or
12
times
greater
than
the
exposed
skin
surface
area
in
this
experiment
(
USEPA
1997).
If
both
the
hands
and
forearms
were
exposed,
the
total
exposed
surface
area
would
be
3,900
cm2,
or
49
times
the
surface
area
exposed
in
this
study.
This
discrepancy
is
important,
as
it
has
a
major
impact
on
the
amount
of
compound
that
can
be
absorbed
within
a
defined
time
period.
Dermal
dosing
studies
require
careful
consideration
of
three
factors:
mass
applied
to
the
skin,
surface
area
treated,
and
the
duration
of
exposure.
These
three
factors
are
typically
used
to
determine
the
flux
of
a
chemical
through
the
skin
(
e.
g.,
mg/
cm2/
hr).
Percent
absorbed
is
highly
dependent
on
the
skin
loading,
or
mass
applied
per
unit
area
(
e.
g.,
mg/
cm2).
The
relationship
between
skin
loading
and
percent
absorbed
was
made
clear
in
a
review
of
studies
in
the
rat
by
Zendzian
(
2000).
In
the
case
of
azinphos­
methyl,
for
example,
a
loading
of
3
nanomole/
cm2
for
10
hours
resulted
in
23%
absorption,
a
loading
10­
fold
higher
(
29
nmolesM/
cm2)
resulted
in
15%
absorption,
and
a
further
10­
fold
increase
in
loading
(
293
nmoles/
cm2)
resulted
in
only
2.9%
absorption.
These
azinphos­
methyl
loadings,
expressed
as
mass
per
unit
area,
were
0.95,
9.2,
and
93
µ
g/
cm2,
respectively.
In
earlier
dermal
dosing
studies
involving
humans,
radio­
labelled
pesticides
were
applied
at
loadings
of
4
and
40
µ
g/
cm2
(
Feldmann
and
Maibach
1974).
It
is
evident
that
the
skin
loadings
in
the
amitraz
study
were
several
orders
of
magnitude
higher
than
those
used
in
the
above
cited
studies.
The
key
point
is
that
chemical
loadings
on
small
areas
of
skin
result
in
relatively
small
amounts
of
chemical
absorbed.
In
this
dermal
toxicity
study,
the
loadings
were
so
high
that
the
three
"
dose"
levels
were
essentially
equivalent
in
terms
of
dermal
absorption
potential.

If
it
is
assumed
that
the
flux
of
amitraz
in
these
experiments
was
approximately
2
µ
g/
cm2/
hr,
as
has
been
estimated
from
a
study
of
chlorpyrifos,
a
lipophilic
insecticide
with
a
similar
molecular
weight
(
Nolan
et
al.
1984),
then
the
total
mass
absorbed
in
the
amitraz
62
of
69
experiments
over
10
hours
would
have
been
approximately
1,000
µ
g
(
1
mg),
or
an
absorbed
dose
of
0.014
mg/
kg.
If
this
same
flux
were
applied
to
an
exposure
to
the
hands
and
forearms
of
a
worker,
the
total
mass
absorbed
would
be
approximately
50,000
µ
g
(
50
mg),
or
an
absorbed
dose
of
0.71
mg/
kg,
well
above
both
the
0.125
mg/
kg
single
oral
dose
"
no
effect"
level,
and
the
0.25
mg/
kg
single
oral
dose
that
elicited
multiple
signs
and
symptoms
of
neurotoxicity.
It
is
for
this
reason
that
the
amitraz
dermal
toxicity
study
cannot
be
considered
a
"
no
effect"
study
for
risk
assessment
purposes.

HSRB
Consensus
and
Rationale
a.
The
Board
concluded
that
the
results
from
the
single
oral
dose
study
were
informed
by
the
human
metabolism
study
such
that
the
single
oral
dose
study
is
appropriate
for
developing
a
point
of
departure
for
acute
dietary
risk.

The
appearance
of
overt
signs
and
symptom
of
toxicity
in
the
1984
oral
metabolism
study
at
a
dose
of
0.25
mg/
kg
provides
some
confidence
that
the
highest
dose
(
0.125
mg/
kg)
in
the
1992
single
oral
dose
study
represent
a
no
observable
adverse
effect
level
(
NOAEL)
for
an
acute
dietary
exposure
to
amitraz.
No
effects
of
neurologic
toxicity
were
observed
in
any
of
the
study
subjects
at
0.125
mg/
kg.
This
conclusion
rests
on
the
assumption
that
the
psychomotor
tests
applied
to
the
subjects
were
the
most
sensitive
endpoints
for
neurotoxicity,
and
that
they
were
conducted
properly.
There
was
considerable
uncertainty
regarding
these
psychomotor
tests,
as
the
procedures
used
were
not
described
in
the
study,
and
no
quality
assurance
information
was
provided.
Thus,
the
findings
from
this
study
should
be
used
with
caution
for
risk
assessment
purposes.

b.
The
Board
concluded
that
the
combined
results
from
the
single
oral
dose
study
and
the
human
metabolism
study
were
not
appropriate
for
developing
a
point
of
departure
for
chronic
dietary
risk,
short­
term
oral
exposure,
or
inhalation
risk.

A
single
oral
dose
of
0.25
mg/
kg
elicited
frank
symptoms
of
toxicity
in
both
subjects
in
the
1984
metabolism
study.
Multiple
signs
and
symptoms
were
observed
in
the
subjects
for
several
hours
post­
dosing,
and
at
least
one
sign
(
bradycardia)
was
still
present
at
12
hours
postdose
Excretion
of
radio­
labeled
metabolites
was
incomplete
(
62%)
at
24
hours.
The
proposed
NOAEL
is
only
one­
half
the
dose
used
in
the
1984
study.
Thus,
subjects
exposed
to
repeated
daily
doses,
as
would
occur
in
short­
term
or
chronic
oral
dose
studies,
would
achieve
a
cumulative
dose
of
0.25
mg/
kg
within
48
hours.
It
seems
quite
possible
that
repeated
short­
term
oral
exposures
or
chronic
oral
exposures
would
elicit
at
least
some
effects
in
humans
within
a
very
few
days.
Thus,
the
available
data
did
not
demonstrate
a
no­
effect
level
for
multi­
day
oral
exposures.
In
regard
to
inhalation
exposures,
absorption
through
the
respiratory
tract
is
generally
more
efficient
than
absorption
through
the
gastro­
intestinal
tract.
It
is
quite
possible
that
adverse
effects
would
have
been
observed
in
an
inhalation
exposure
study
that
delivered
0.125
mg/
kg
as
a
single
dose.
Also,
an
oral
dose
study
would
not
capture
adverse
effects
unique
to
exposure
by
the
inhalation
route.
Thus,
the
available
data
do
not
demonstrate
that
the
oral
NOAEL
and
the
inhalation
NOAEL
were
equivalent.
63
of
69
c.
The
majority
of
the
Board
concluded
that
the
human
dermal
study
was
not
appropriate
for
developing
a
point
of
departure
for
dermal
exposures
of
various
durations.

The
HSRB
members
did
not
consider
the
dermal
toxicity
study
to
be
a
valid
scientific
study
for
risk
assessment
because:
1)
the
study
involved
extremely
high
loadings
(
mass
per
unit
surface
area)
of
amitraz
on
the
skin,
making
the
three
dose
levels
used
in
the
study
very
nearly
equivalent
in
regard
to
dermal
absorption
potential,
and
not
equivalent
to
worker
exposure
scenarios;
2)
the
study
did
not
demonstrate
an
effect
(
i.
e.,
the
study
was
equivalent
to
a
"
NOAEL­
only"
study);
and
3)
there
was
no
corroborating
evidence
to
demonstrate
that
an
internal
dose
had
been
delivered
to
the
subjects
by
the
dermal
route.
One
member
of
the
HSRB,
while
agreeing
with
these
scientific
criticisms,
considered
that
the
study
might
still
be
of
use
to
the
Agency.

8.2.
Ethical
considerations
Charge
to
the
Board
a.
The
Agency
requested
that
the
Board
provide
comment
on
the
following:

With
respect
to
the
Campbell
(
1984)
research,
whether
the
lack
of
medical
surveillance
of
subjects,
following
the
termination
of
dosing,
to
establish
that
subjects'
signs
of
adverse
effects
had
returned
to
normal
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;
and
With
respect
to
the
Cass
(
1992)
and
the
Langford
(
1998)
studies,
whether
references
to
the
test
material
as
a
drug
and
other
statements
that
could
indicate
the
study
constituted
medical
research,
that
appeared
in
the
materials
used
to
obtain
informed
should
be
considered
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted;
and
b.
The
Agency
asked
that
the
Board
provide
comment
on
the
following,
taking
into
account
all
that
is
known
about
the
ethical
conduct
of
each
study:

OPP's
conclusion
that
there
was
not
clear
and
convincing
evidence
that
the
conduct
of
the
research
was
fundamentally
unethical.

Whether
there
was
clear
and
convincing
evidence
that
the
conduct
of
the
study
was
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

Board
Response
to
the
Charge
The
compound
amitraz
is
an
alpha­
two­
adrenergic
agonist
that
produces
sympatholytic
effects
leading
to
sedation
and
other
neurological
signs
and
symptoms,
as
well
as
cardiovascular
depression
with
a
drop
in
blood
pressure
and
heart
rate.
The
studies
under
ethical
review
include
two
metabolic
studies
in
1984
using
C14
radio­
labeled
isotope
technology,
a
1992
oral
dosing
study,
and
a
1998
dermal
absorption
study.
64
of
69
The
two
metabolic
studies
were
performed
in
1984
and
involved
two
volunteer
subjects.
The
oral
dosing
study
was
performed
in
1992
and
involved
six
research
subjects
(
with
an
additional
(
1)
subject
withdrawn
for
an
unrelated
rash).
The
oral
dosing
study
was
a
doubleblind
randomized,
placebo­
controlled,
crossover
study
involving
two
different
doses.
The
oral
dosing
study
progressed
in
three
phases,
escalating
from
the
lower
dose
to
the
higher
dose.
The
protocol
stated
that
the
research
was
in
compliance
with
the
1989
version
of
the
Declaration
of
Helsinki,
an
early
version
of
good
clinical
practice
(
GCP)
guidelines
promulgated
by
the
EMEA
(
111­
3976­
88­
EN),
the
ABPI
Guidelines
for
Medical
Experiments
in
Non­
Patient
Human
Volunteers
(
1988,
1990),
the
1986
RCP
Guidelines
on
Research
Using
Healthy
Volunteers,
the
FDA
Compliance
Program
for
Drugs
and
Biologics
and
the
GCP
guidelines
from
Japan
that
were
current
in
1992
(
Notification
No.
874
from
the
Ministry
of
Health
and
Welfare).
The
approval
of
the
research
ethics
committee
was
given
on
November
20,
1991,
but
no
information
was
provided
about
the
substance
and
process
of
that
review.

The
dermal
absorption
study
was
performed
in
1998
and
involved
eight
research
subjects.
The
study
was
a
double­
blind,
randomized,
placebo­
controlled,
crossover
study
involving
three
different
doses
(
in
a
four
phase
dose
escalation
design).
The
protocol
stated
that
the
research
was
in
compliance
with
the
above
standards,
with
the
updated
GCP
guidelines
promulgated
in
1996.
The
approval
of
the
research
ethics
committee
was
given
on
December
22,
1997,
although
no
information
was
provided
about
the
substance
and
process
of
that
review.

Critique
of
Study
The
Board
concurred
with
the
factual
observations
of
the
strengths
and
weaknesses
of
the
two
1984
metabolic
studies,
as
detailed
in
Carley
(
2006i).
Specifically,
there
was
no
justification
for
the
dose
selection,
no
record
of
independent
committee
review,
and
no
record
of
informed
consent
(
other
than
the
description
of
the
participants
as
volunteers).
The
dose
selected
did
result
in
adverse
events
as
might
be
expected
from
the
administration
of
a
product
with
this
pharmacological
profile.
The
period
of
recorded
observations
was
eight
hours,
and
stated
observation
time
was
12
hours.
Although
the
period
of
observation
was
insufficient
to
assure
that
the
physiologic
condition
of
the
volunteers
had
returned
to
baseline,
the
known
physiologic
effects
of
the
compound
are
such
that
the
period
of
observation
was
sufficient
to
assure
the
lack
of
significant
adverse
effects.

The
Board
concurred
with
the
factual
observations
of
the
strengths
and
weaknesses
of
the
1992
oral
dosing
study
as
documented
in
Carley
(
2006i).
Of
note
was
that
the
volunteer
information
included
information
about
the
risks
of
the
administration
of
the
study
compound
which
were
relatively
complete
in
the
scope
of
the
risks
described
(
yet
absent
a
few
details
within
each
organ
system).

The
Board
concurred
with
the
factual
observations
of
the
strengths
and
weaknesses
of
the
1998
dermal
absorption
study,
as
documented
in
Carley
(
2006k).
Although
concern
had
been
expressed
about
the
choice
of
dose,
the
study
design
involved
a
dose
escalation
such
that
adverse
events
at
lower
doses
could
have
been
anticipated.
65
of
69
HSRB
Consensus
and
Rationale
The
Board
concluded
that:

a)
The
amitraz
acute
oral
and
dermal
human
toxicity
studies
failed
to
fully
meet
the
specific
ethical
standards
prevalent
at
the
time
the
research
was
conducted,
however
b)
There
was
no
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical­­
intended
to
seriously
harm
participants
or
that
informed
consent
was
not
obtained,
and
c)
There
was
no
clear
and
convincing
evidence
of
significant
deficiencies
in
the
ethical
procedures
that
could
have
resulted
in
serious
harm
(
based
on
the
knowledge
available
at
the
time
the
study
was
conducted),
nor
that
information
provided
to
participants
seriously
impaired
their
informed
consent.

Although
the
Board
concurred
in
the
noted
deficiencies
with
the
1984
metabolic
studies,
the
Board
did
not
consider
the
lack
of
documentation
of
medical
supervision
following
the
termination
of
dosing
in
the
1984
metabolic
studies
to
be
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

The
Board
also
acknowledged
the
observations
that
the
1992
oral
dosing
study
and
the
1998
dermal
absorption
study
included
potentially
misleading
references
in
the
informed
consent
documents.
However,
the
Board
does
not
believe
that
these
deficiencies
could
have
resulted
in
serious
harm
based
on
the
knowledge
available
to
the
investigators
at
the
time,
nor
seriously
impaired
the
informed
consent
of
the
research
subjects.
As
such,
the
Board
did
not
consider
these
findings
significantly
deficient
relative
to
the
ethical
standards
prevailing
when
the
study
was
conducted.

The
Board
concurred
with
the
assessment
of
the
Agency
that
there
was
not
clear
and
convincing
evidence
that
the
conduct
of
the
research
was
fundamentally
unethical.
The
research
as
designed
and
conducted
was
not
intended
to
seriously
harm
participants
nor
failed
to
obtain
informed
consent.
Thus,
the
Board
concluded
that
there
was
no
ethical
objection
to
the
appropriate
use
of
the
data
from
these
studies
(
as
discussed
in
the
scientific
assessment)
given
the
absence
of
clear
and
convincing
evidence
that
the
research
was
fundamentally
unethical
or
significantly
deficient
relative
to
the
ethical
standards
prevailing
at
the
time.
66
of
69
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