Clinical Trial Details
— Status: Completed
Administrative data
| NCT number |
NCT04028180 |
| Other study ID # |
928 |
| Secondary ID |
|
| Status |
Completed |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
November 19, 2018 |
| Est. completion date |
February 13, 2019 |
Study information
| Verified date |
July 2019 |
| Source |
ARCTEC |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
Comparison trial between two repellent products and a positive control against Culicoides
nubeculosus midges. A single-centre laboratory setting study using healthy volunteers to test
two insect repellent products and a positive control product against Culicoides nubeculosus
midges. The test products are designed for use by the general public in areas where midge
biting is likely.
Description:
Mosquitoes, midges and other biting insects are vectors of extremely important diseases such
as malaria, yellow fever, filariasis and many viruses and also may be of great nuisance
value. The use of repellent products can provide added personal protection from disease
transmission and nuisance bites. New effective repellents would offer an additional option
for protection against biting insects. The aim of this study is to determine the
effectiveness of two topically applied insect repellent products provided and one positive
control against Culicoides nubeculosus. Culicoides nubeculosus is a common species of biting
midges belonging to the family Ceratopogonidae. Culicoides midges are small biting flies
found throughout the world, breeding primarily in moist, damp, muddy habitats. To develop
their eggs, female Culicoides require a blood meal from warm-blooded vertebrates, most often
a domesticated animal and humans. Culicoides are implicated in the transmission of multiple
zoonotic diseases, such as bluetongue virus, African horse sickness, and bovine ephemeral
fever, and their bites can be painful and can cause uncomfortable irritation to both humans
and livestock.
This is a single-centre, single-arm study with all participants testing two formulations
containing PMD and a positive control product containing Picaridin. The control for each test
is an untreated arm. There is no blinding or randomisation employed, since the outcome
measures are based on midge behaviour. Repellent product testing takes place in a laboratory
setting using 7 participants (preferably gender balanced). Each participant will test both
PMD formulations and a positive control product.
Volunteers will be consented prior to any screening procedures being undertaken. Volunteers
who do not meet the criteria for eligibility will be excluded. In order to assess sensitivity
in those volunteers who claim not to be sensitive to insect bites, volunteers will be given a
bite test using the midge species used for testing. Participants can stop at any time without
giving a reason for withdrawing. Data collected to the point of withdrawal will be used in
the analysis of the study, unless the participant requests that their data is not used, in
which case it will be removed from the database. Participants may also be removed at the
discretion of the Chief Investigator, where continued participation may affect the safety of
the participant or where there is a development of any condition which might interfere with
study participation.
All adverse events and serious adverse events should be reported. Any questions concerning
adverse event reporting should be directed to the chief investigator in the first instance.
The midges will be obtained from insecticide-susceptible reference strains held at the
Pirbright Institute (Institute for Animal Health). They will be maintained at 22-24°C, 80-90%
relative humidity, with a 12:12 hour photoperiod. Female midges will be host-seeking, of
uniform age and 3-8 days post-emergence. Active host-seeking females will be selected to
ensure a good response from the test midges using an aspirator or an appropriate airflow
apparatus. Before the start of each test, the participant will insert a bare (control) left
arm into the cage for 1 minute to assess biting activity of the midges. Only cages with at
least 10 midges landing within one minute will be used in the tests. This same procedure is
used to assess whether volunteers are attractive to the midges. The number of midges probing
or biting the arm after 1 minute will be counted and recorded (to provide biting rate data of
the control test for the Protective Efficacy endpoint) and the arm removed from the cage.
Immediately after, the right (treated) arm is inserted into the cage for 1 minute. The number
of midges probing or biting the arm after 1 minute will be counted and recorded. A further
hour post-application of the repellent product, the left arm (control) of the volunteer is
again inserted into the cage. The number of midges probing or biting the arm after 1 minute
will be counted and recorded and the arm removed from the cage. If less than 10 midges land
on the untreated arm during this 1 minute test the cage will be refreshed with new midges and
the test repeated. Immediately after, the right (treated) arm is again inserted into the cage
for 1 minute. The number of midges probing or biting the arm after 1 minute will be counted
and recorded. This procedure will be repeated at hourly intervals throughout the test.
The products will be applied to the forearm between the wrist and elbow. Volunteers' forearm
surface area is estimated using the WHO protocol for testing skin repellents below:
Area=1⁄(2 ) (C_W+C_E ) X D_EW
Where CW is the circumference of the wrist; CE is the circumference of the elbow; and DEW is
the distance between the wrist and elbow in centimetres (cm). The dose is expressed using
µl/cm2. The appropriate dose is then measured using a micropipette or balance and applied to
the arm using a gloved finger.
Participants will be followed up within 72 hours after the test to assess any possible side
effects or reactions to the bites and/or products.
With the exception of the Volunteer Questionnaire, which is completed by the participant, all
data collected will be recorded in the case report forms (CRF) and signed by the person
completing the CRF. The CRF is considered to be source data. Data to be collected are:
Participant number and date of visit on every page, confirmation of informed consent, date of
birth, eligibility details, bite test details (midge species, timing, 10 min and 72 h
assessments), test visits (eligibility checklist, forearm measurement, product details,
product application details, arm-in-cage testing data (time, fitness check, No. midges
probing control arm, No. midges probing treated arm)) and adverse event monitoring. Data will
be double entered and verified to ensure accuracy. CRFs will be kept in locked storage.
Information in the database for each test will be linked to a relevant SOP, risk assessment,
contract, and files of statistical analysis and location of report copy.
