EPA Review of Tick Repellent Testing Protocol

1

Kevin Sweeney

Kevin Sweeney

Eric Bohnenblust, Ph.D.

Eric Bohnenblust, Ph.D.

Maureen Lydon

Maureen Lydon

Office of Pesticide Programs

Office of Pesticide Programs

EPA Review of i2LResearch

USA, Inc. Protocol

Testing of S.C. Johnson Personal Tick Repellent

Testing of S.C. Johnson Personal Tick Repellent

Products to Support their Use of the EPA

Products to Support their Use of the EPA

Repellency Awareness Graphic.

Repellency Awareness Graphic.

Overview

i2LResearch submitted a protocol for

testing insect repellent products against

ticks in the laboratory to determine the

Complete Protection Time (CPT) of their

18 skin applied repellent products to

support the use of the EPA Repellency

Awareness Graphic.

2

Overview (2)

Testing will be conducted by i2L Research

USA, Inc. in Baltimore, Maryland.

Testing will be conducted against 3 tick

species with up to 30 different human

subjects per product (10 per species).

3

Comparisons to Skin-Applied Repellent

Protocols Reviewed by the HSRB

In this protocol:



Aerosol and lotion products are proposed to be tested at 1

g/600cm

2



Spritz/pump sprays are proposed to be tested at 0.5

g/600cm

2



A dosimetry phase is not proposed.

•

This is a departure from the design of repellent efficacy studies that that have been

reviewed and approved by EPA and the HSRB in recent years, which have

experimentally determined the dose.

4

What is the Repellency Awareness

Program?

A program to raise public awareness of the health

protectiveness of mosquito and tick repellents

applied to the skin.

Purposes

:



Raise consumer awareness of the efficacy of skin-

applied insect repellents.



Increase EPA and consumer confidence in the efficacy

claims on labels.



Improve consumer protection against vector borne

diseases, such as Lyme disease and West Nile virus.

EPA Repellency Awareness Graphic

6

Repellency Awareness Graphic

The graphic clearly informs consumers

about the duration of repellent protection

so that they can make informed choices

about the repellent products they

purchase and use.

7

8

Science Assessment:

Science Assessment:

Testing of S.C. Johnson Personal Tick

Testing of S.C. Johnson Personal Tick

Repellent Products to Support their Use of

Repellent Products to Support their Use of

the EPA Repellency Awareness Graphic

the EPA Repellency Awareness Graphic

Kevin Sweeney

Eric Bohnenblust, Ph.D.

Registration Division

Office of Pesticide Programs

9

Study Objectives

To determine the complete protection time

(CPT) of up to eighteen EPA registered skin

applied repellent products from S.C. Johnson &

Son, Inc. in the laboratory against adults of 3

tick species using volunteer human subjects to

support use of the EPA Repellency Awareness

Graphic on the product label.

Study Objectives (2)

The data provided from this research can be

used by the EPA to support the addition of the

Repellency Awareness Graphic to skin applied

insect repellent labels, thereby allowing for

better protection of consumers from nuisance

arthropod bites and bites that lead to

arthropod-borne diseases.

10

11

Acute Toxicity of the Test Materials

All test materials are S.C. Johnson Products

registered by the EPA as skin applied insect

repellents.



Acute Dermal LD

50

 >2,000 mg/kg body weight



Minimally irritating to the skin and eyes.



Not skin sensitizers.

12

Margin of Exposure (MOE) Estimate

S.C. Johnson prepared an estimate of the Margin

of Exposure via the dermal route for each of the

18 products to be tested.

The proposed exposures to the subjects in these

tests are not of concern for the three active

ingredients to be tested.

Calculated Margins of Exposure for DEET Products

Calculated Margins of Exposure for DEET Products

13

Table 1:

Calculated Margins of Exposure for Picaridin Products

Calculated Margins of Exposure for Picaridin Products

14

Table 2: 

Calculated Margins of Exposure for

p-Methane-3, 8-Diol (PMD) Products

15

Table 3: 

Dosage and Product Application

i2LResearch will not include a dosimetry phase to

determine “typical consumer dose.”

Instead, i2LResearch proposes standardized rates

of:



1 g/600cm

2 

for aerosol and lotion products



0.5 g/600cm

2 

for Spritz/pump sprays

16

Dosage and Product Application (2)

A set dose can be related to known

consumer behavior based on past tests

reviewed by the HSRB where dosimetry

was employed for skin applied insect

repellent products.

17

Dosage and Product Application (3)

The HSRB determined during their April meeting that a dose of 1

g/600cm

2

 was appropriate for all product types.

However, based on analysis of dosimetry results from repellent

studies reviewed since 2006, EPA recommends the following

doses be used for studies conducted using this protocol:



Aerosol/lotion – 1 g/600cm

2



Towelette/pump spray 0.5g/600cm

2

Data may be bridged from a pump spray to a towelette because

pump spray and towelette formulations are usually similar and the

pump spray is applied at a lower dose.

18

Experimental Design

Experimental Design

For each test, 10 subjects (5 males and 5 females) will

be treated with the test substance. Two additional

subjects (one male and one female) will serve as

alternates for each test.



The test subjects will be selected at random from a pool of

potential subjects from the area around Baltimore, MD.

19

Experimental Design (2)

Experimental Design (2)

For each product there will be a total of up to 30

different treated subjects and up to 6 different alternate

subjects.



The subjects will not be blinded to the test substances with

which they are treated.



If subjects participate in more than 1 test, the tests must be

separated by a minimum of 2 days. Subjects are required to

wash after each test.

A positive control substance will not be used.

20

Experimental Design (3)

Experimental Design (3)

Each subject will have one forearm treated with the

repellent product to be tested, and the other arm will

serve as the untreated control.



Assignment of the test substance to the subject’s arms will

be randomized.



The control arm will be used to qualify ticks that are active,

and determine the attractiveness of the subject to ticks.

The data collected from the control arm will not be used

to calculate the Median Complete Protection Time.

21

Experimental Design (4)

Four lines will be drawn on both of the subjects’

forearms as follows:



‘Release line’ 3 cm above the wrist bone towards the elbow



‘Boundary line’ 3 cm above the release line towards the

elbow (this will be the edge of the treated area)



‘Crossing line’ 3 cm above the boundary line



An upper boundary line 12 cm above the boundary line; this

will not be used during testing and serves only to denote the

boundary of the treated area.

22

Experimental Design (5)

23

‘Release line’

‘Upper boundary’

‘Crossing line’

‘Boundary line’

24

‘Release line’

‘Boundary line’ 

‘Crossing line’

‘Upper boundary’

Experimental Design (6)

Ticks will be trialed to make sure they will actively quest.

To qualify this behavior, ticks will be placed at the ‘release

line’ on the untreated control arm and then must cross the

boundary line within 3 min.

Treatments will be challenged with 1 tick every 15 minutes

(4 ticks/h).

25

Experimental Design (7)



Once qualified, the ticks will be placed at the ‘release line’ on

the treated arm.



After the tick begins to move up the arm, it will be given 3

minutes to cross the ‘boundary’ and ‘crossing’ lines on the

treated arm.



Ticks are considered repelled if in 3 min. they do not:



Reach the ‘boundary’ line



Reach the ‘crossing’ line



Ticks are considered not repelled if in 3 min. they reach the

crossing line.

26

27

Experimental Design (8) – DEET Products

Experimental Design (8) – DEET Products

28

Experimental Design (9) – Picaridin Products

Experimental Design (10) – PMD Products

29

30

Endpoints and Measures



Unit of measure for determination of the

repellent effects is Complete Protection Time

(CPT).



“The CPT for each tick species will be calculated as

the time from test substance application to the time

of the First Confirmed Crossing. The time in hours for

each individual test subject will be used to calculate

the median protection time for each species

separately.”

Endpoints and Measures (2)



A ‘Crossing’ occurs when a tick crosses the

‘crossing line’  within 3 min. on the treated

arm of a subject.



A ‘First Confirmed Crossing’ is that which is

followed by the subsequent tick crossing in

the next exposure period, or the first

subsequent tick is repelled but the second

subsequent tick is recorded as not being

repelled.

31

Statistical Analysis Plan



The objective of the data analysis is to

estimate the Median Complete Protection

Time.



The Median CPT of all test subjects will be

calculated using the Kaplan-Meier Survival

Analysis, which is advantageous since

CPTs may not be normally distributed.

32

Statistical Analysis Plan (2)

33

Table 1:Kaplan-Meier Median Confidence Limits for a Range of Sample Sizes.

As evidenced by the table, sample sizes larger than ten would

provide only marginal increases in precision relative to the increase

in the number of exposed test subjects.

Statistical Analysis Plan (3)

The Kaplan-Meier Survival Analysis has

been accepted by EPA and the HSRB for

the Median CPT calculation in past

efficacy studies using repellents and is

also recommended by the World Health

Organization for CPT calculation from

these data sets.

34

Statistical Analysis Plan (4)

The proposed sample size of 10 subjects

per study represents a reasonable

compromise between increasing precision

and limiting costs based on past analyses

by the EPA.

35

36

Measures to Ensure Reliability



Good Laboratory Practices, as defined by 40 CFR part 160 will be followed throughout all

studies.



Study staff will conduct a training session with the subjects on a day prior to the test date.



Study staff will treat the skin of the exposed limb with the test substance and the limb will

be measured in advance.



Study staff will place ticks on the untreated and treated arms.



Study staff will monitor and record tick movement and the start and stop times for each

exposure period.



Study staff and the study director will track test substance samples, closely monitor the

testing, and data recording.



Alternate subjects will be enrolled to ensure adequate sample size.



A Quality Assurance Unit will be in place to monitor all study activities and data collection.



Test subjects can only take part once in any two-day testing period. If scheduled to

participate in two studies within one week, there will be two calendar days in between test

days.

37

Compliance with Scientific Standards

The following elements are adequately

addressed:



Available 

toxicity studies 

with DEET, picaridin, and

PMD.

•

Adequately characterize toxicological profile of

the formulations.

•

Data to support estimate of acceptable Margin

of Exposure (MOE).

Compliance with Scientific Standards

The following elements are generally

acceptable but require refinement and

clarification:

•

Pre-Training

•

Experimental Design

•

Data Analysis

38

Science Comments and

Recommendations 1

1) EPA comment

: “Pre-training of subjects is

barely described. More information is required.

The protocol should be explicit with regard to

the training outline and specific topics to be

addressed.”

S.C. Johnson & i2L response: 

Revised

section 2.2.5 with an outline providing specifics

for pre-training.

39

Science Comments and

Recommendations 2

2) EPA comment

: “Please provide more details on the

exact timing of the testing. The protocol needs to

explicitly describe the amount of time the technician has

to do testing and the amount of time in a 15 minute

period that requires the subject to be seated and

exposed to ticks.”

S.C. Johnson & i2L Research response

: Revised

protocol to include specific details regarding testing.

40

Science Comments and

Recommendations 3

3) EPA comment

: “Repellent sample size

selection: The protocol cites one example of the

effect of sample size on mean confidence

interval width when changed from 10 to 20

subjects. Submit a simulation showing the

impact of increasing sample size on the width of

95% confidence interval of median CPT where

median CPT will be estimated using Kaplan

Meier method. This can be presented in table

form.”

41

Science Comments and

Recommendations 3 continued

S. C. Johnson & i2L Research

response:

 “Sample size is adequate and

is unlikely to overestimate CPT due to

selection of the lowest CPT value, and

historical precedent.”

42

Science Comments and

Recommendations 3 continued

S. C. Johnson & i2L Research

response continued: 

“The confidence limits associated with the

Kaplan-Meier median are positional values

in the distribution, rather than calculated

values as in the case of a confidence

interval around the mean.”

43

Science Comments and

Recommendations 3 continued

S.C. Johnson & i2L Research response

continued: 

“

The table from slide 32 indicates which positions in the

distribution of values constitute the lower confidence

limit (LCL) and upper confidence limit (UCL) of the

median for various sample sizes. The assumption is that

the values are sorted in increasing order, so value “1” in

the distribution refers to the smallest value (i.e., the

minimum).”

44

Science Comments and

Recommendations 4

4) EPA Comment:

 A randomization

mechanism needs to be inserted into

sections 2.3.8 and 2.3.9.

S.C. Johnson & i2L Research

response:

 Will use a random number

generator from a statistical software

package (e.g., Minitab, Excel)

45

46

Science Comments and

Recommendations 5

5) EPA Comment:

 Amend the protocol to

require subjects to wait at least two calendar

days (48 hours) between tests if they participate

in multiple tests.

S.C. Johnson & i2L Research response:

Amended the protocol to require subjects wait

two days between participating in different tests

Compliance with Scientific Standards

As amended to address the concerns raised in the EPA review, the

i2L Research USA protocol entitled “Testing of S.C. Johnson

Personal Tick Repellent Products to Support their Use of the EPA

Repellency Awareness Graphic” is likely to yield scientifically

reliable information, satisfying the following scientific criteria from

the framework recommended by the HSRB:



It would produce important information that cannot be

obtained except from research with human subjects.



It has clear scientific objectives.



The study design should produce adequate data to achieve

those objectives.

47

48

Ethics Assessment:

Ethics Assessment:

Testing of S.C. Johnson Personal Tick

Testing of S.C. Johnson Personal Tick

Repellent Products to Support their use of the

Repellent Products to Support their use of the

EPA Repellency Awareness Graphic

EPA Repellency Awareness Graphic

Maureen Lydon

Maureen Lydon

Office of the Director

Office of the Director

Office of Pesticide Programs

Office of Pesticide Programs

49

Value to Society



Proposed study will determine the

complete protection time (CPT) of up to 18

EPA-registered insect repellent products

against ticks



Up to 3 different active ingredients (AIs)

and variety of products, all previously

registered and assessed by EPA, will be

tested for duration of efficacy



Product-specific efficacy testing is required

to support use of EPA’s Repellency

Awareness Graphic on product labels.

50

Value to Society 2



Consumers who use tick repellents to avoid

tick bites cannot readily assess the

duration of repellency.



If EPA’s Repellency Awareness Graphic is

added to the label, consumers can make

informed decisions by knowing the length

of time each product repels ticks.

51

Subject Selection



Participants will be recruited through

advertising using digital and social media.



Recruitment firm will also use Spanish

language advertisement and on-line

Spanish newspaper that advertises in the

recruitment area.



Ad will contain link to study-specific website

with prescreening qualification form.

Subject Selection 2



Once completed, pre-screening

qualification form will be uploaded to

secure and encrypted portal, that only

i2LResearch staff can access.



The respondents who meet the

eligibility criteria will be contacted

initially by the recruitment firm or

i2LResearch.

52

Subject Selection 3



The respondents will be asked some

basic eligibility questions and told about

the test using the telephone script.



Eligible/interested respondents will

receive follow-up call from i2lResearch

to review study steps, identify training,

inclusion/exclusion factors, payment,

and offer to provide consent form.

53

Subject Selection 4



Next step is 2 hour training prior to

each study.



As part of training, consent form will be

provided and reviewed. Questions will

be asked to ensure understanding.



Eligible interested subjects will sign

consent form.

54

Inclusion/Exclusion Criteria



15 inclusion/exclusion criteria are

complete and appropriate, except:

o

Add exclusion for sensitivity to tick bites or

latex.

o

Add exclusion for individuals with skin

disease, skin problems such as eczema,

psoriasis or atopic dermatitis.

55

Inclusion/Exclusion Criteria 2



One of the inclusion criteria:

o

Read and speak English fluently.

Rationale:

o

Current repellent product labels in English

o

Language does not affect attractiveness to

ticks

56

Inclusion/Exclusion Criteria 3

Rationale (continued):

o

To target users that understand product

labels, will recruit English speaking

subjects with minimum 10% bilingual

o

Research offers no benefits to subjects

o

Limiting recruitment to English speakers

with 10% bilingual, is not expected to

result in equity of access issues

57

58

Informed Consent Process



Proposed consent process with EPA

comments included is satisfactory

•

Potential subjects meet with i2LResearch for 2 hour

training.  Subjects given consent form, time to read it,

opportunity to ask questions

•

As part of training, the study, subject’s role, potential

length of test day, inclusion/exclusion criteria will be

reviewed

•

Questions will be asked to ensure understanding

•

Pregnancy test within 48 hours prior to test day



Revised consent form includes all elements

required by regulations

59

Informed Consent 2



To confirm understanding of the consent

form, subjects will be asked 6 questions:

1. What will study staff place on your

arm, monitor, take off & discard in order

to collect study data?

2. What type of product will be applied to

your arm and remain on your arm during

the exposure period of the study?

3. How long could one test day last?

60

Informed Consent 3



To confirm understanding of the consent

form, subjects will be asked 6 questions:

4. What are the potential discomforts or

hazards from this study?

5. Do you have the freedom to quit or

withdraw from the study at any time?

6. If you quit or withdraw from the study,

for how many hours will you be paid?

Highlights of EPA Comments



Revise protocol to include details of

training and what will occur.

•

i2LResearch & SCJ: Revised accordingly 





Revise description of recruitment

process and provide details. Also,

include Spanish language ad and use of

online Spanish newspaper

•

i2LResearch & SCJ: Revised accordingly 



61

EPA Comments 2



Add breaks during test day. Provide

breakfast, lunch, dinner to subjects

•

i2LResearch & SCJ: Revised accordingly 





Increase proposed compensation for

participating in training and test day

•

i2LResearch & SCJ: Revised accordingly 



62

EPA Comments 3



Reduce length of 2 hour prep time on

test day

•

i2LResearch & SCJ: Revised accordingly 





Pregnancy test should occur within 48

hours prior to test day instead of on

test day

•

i2LResearch & SCJ: Revised accordingly 



63

EPA Comments 4



Draft questions to ensure

understanding of consent form

•

i2LResearch & SCJ: Revised accordingly 





Clarify when and how often consent

form will be signed if subject

participating in more than 1 study

•

i2LResearch & SCJ: Revised accordingly 



64

EPA Comments 5



In consent form, include:

o

 section on Test Material

o

 detailed description of training

o

 provision of breaks

o

 provision of breakfast, lunch and dinner

o

 discomfort of and fatigue from long test

day as another risk

•

i2LResearch & SCJ: Revised accordingly 



65

EPA Comments 6



Revise phone scripts for initial and

follow-up contact to:

Clarify length of test day and

training, explain use of code

numbers for privacy, update

compensation figures, highlight

freedom to withdraw

•

i2LResearch & SCJ: Revised accordingly 



66

EPA Comments 7



For the follow-up contact script, also

add that breaks and meals will be

provided

•

i2LResearch & SCJ: Revised accordingly 





Add support to help bolster subject’s

arm when it’s being held at 45 degree

angle during test

•

i2LResearch & SCJ: Revised accordingly 



67

EPA Comments 8



Add that closest hospital to lab and

directions will be identified prior to test

date.

•

i2LResearch & SCJ: Revised accordingly 





Add that sharing new information or

results with subjects will occur “in

timely manner”

•

i2LResearch & SCJ: Revised accordingly 



68

EPA Comments 9



i2LResearch and SC Johnson agreed to

address EPA’s comments.

69

70

Risks and Risk Minimization



Revisions to protocol describe appropriate

measures to minimize 5 types of hazards

o

Adverse reaction to test material

o

Exposure to ticks

o

Exposure to potential tick-vectored diseases

o

Unanticipated loss of confidential information

o

Fatigue and/or physical discomfort from length

of test day

71

Benefits



No direct benefit to subjects



Primary direct beneficiary is sponsor



Another beneficiary is consumer who

uses tick repellents



If EPA’s Repellency Awareness Graphic is

added to product label, consumer will

know how long the tick repellent will be

effective in repelling ticks

72

Risk:Benefit Balance



Risks have been effectively

minimized



Risks are reasonable in light of the

expected societal benefits of the

knowledge likely to be gained

73

Independent Ethics Review



Schulman Associates IRB (SAIRB) reviewed

and conditionally approved the protocol

and informed consent materials



Final approval is conditioned on the

sponsor obtaining HSRB review



SAIRB has AAHRPP accreditation, is

registered with OHRP, and is independent

of the investigators

74

Respect for Subjects



Effective methods for protecting

subjects’ 

privacy



Revised level of compensation is

appropriate



Subjects will be free to withdraw at any

time



Sponsor will reimburse subjects for cost

of any medical care if research-related

injuries occur

75

Applicable Ethical Standards



This is a proposal for third-party research involving

intentional exposure of human subjects to a pesticide,

with the intention of submitting the resulting data to

EPA under the pesticide laws



The primary ethical standards applicable to the

conduct of this research are 40 CFR 26, Subparts K

and L, and FIFRA 12(a)(2)(P)



Attachment 1 to the EPA Review contains a point-by-

point evaluation of how this protocol addresses the

requirements of 40 CFR 26 Subparts K and L

76

Findings in EPA Ethics Review



i2LResearch and SC Johnson agreed

to address EPA’s comments



No deficiencies relative to 40 CFR 26,

subparts K and L, or to FIFRA

§12(a)(2)(P)



Protocol meets the applicable

requirements of 40 CFR part 26,

subparts K and L

77

Charge Questions

Charge Questions

If the lab repellency study protocol is amended

as suggested in EPA’

s and the HSRB

’

s review and

if the research is performed as described:

1.

  Is this protocol likely to generate scientifically

reliable data, useful for estimating the complete

protection time of various EPA-registered S.C.

Johnson skin-applied tick repellents in the lab against

three species of ticks?

2.

  Is the research likely to meet the applicable

requirements of 40 CFR part 26, subparts K and L?