Safety and Pharmacokinetics (PK) of a Polyurethane Tenofovir Disoproxil Fumarate (TDF) Vaginal Ring

Tenofovir disoproxil fumarate (TDF) is a prodrug of TFV (tenofovir), an adenosine nucleoside
monophosphonate (nucleotide) derivative with potent antiretroviral (ARV) activity. TDF
permeates cells more rapidly than TFV resulting in increased intracellular accumulation of
TFV-diphosphate (TFV-DP), the active metabolite. TDF is more potent than TFV and inhibits
HIV-1 (Human Immunodeficiency Virus-1)and herpes simplex virus type 2 (HSV-2) infection in
cell and tissue culture models at approximately 100-fold lower concentrations than TFV,
suggesting that it may be an excellent candidate for prevention of HIV. TDF is licensed for
the treatment of HIV-1 infection in the US, the European Union, Middle East, and Africa.

The study will take place at the Albert Einstein College of Medicine in Bronx, New York, USA.
Each participant will receive an IVR (intravaginal ring) containing TDF or a placebo ring.
The vaginal ring will be worn continuously for 14 days. It will be inserted into the vagina
following cessation of participant's menses, by the study clinician at Visit 3 and removed by
the study clinician at Visit 7. Each participant will be followed for 7 days following ring
removal.

It is hypothesized that both the TDF IVR and placebo IVR will be safe and well tolerated
among healthy, sexually abstinent women on combined-hormonal contraception. The null
hypothesis is that there will be no difference in the safety profile between the active
product and the placebo.

Careful assessments of safety, including systemic and genital tract, will be undertaken with
special consideration for issues related to irritation and systemic toxicity. The design of
the study will allow safety comparisons of TDF ring to a placebo ring. A 14-day safety and PK
study is proposed for this first-in-human study per FDA (For and Drug Administration)
guidance. The study duration was carefully selected to control risk to the study
participants. TFV 1% vaginal gel has been extensively tested in clinical trials at higher
doses (8-fold dose margin) than the predicted dose delivered by the TDF IVR-001 study, and
the TFV gel showed no significant adverse events at this higher dose in thousands of women.

Given the drug release kinetics observed in vitro and in NHP (non-human primate) studies, TDF
and TFV (formed following hydrolysis of the prodrug TDF) concentrations in cervicovaginal
fluid (CVF) are expected to reach steady state within a few days and maintain steady state
concentrations for the duration of the planned 14 days of ring use. Sampling at multiple time
points and sites (vaginal, cervical, rectal and blood) will provide information on drug
distribution, kinetics, and, by sampling after ring removal on Day 14, how long drug
persists. The latter may be important as behavior studies suggest that some women may remove
a ring at time of menses or around sex. To capture systemic absorption, blood will be sampled
to determine drug concentrations in blood plasma and PBMCs (peripheral blood mononuclear
cells). To capture the concentrations of drug within the genital tract, CVF will be sampled
using Dacron swabs of the introitus, ectocervix, and area adjacent to the ring. Rectal
sampling with swabs will also be obtained if participants consent to the procedure to
determine drug concentrations in the rectum. Sampling at different sites (proximal and distal
to the ring) will provide important information as to how well drug permeates throughout the
genital tract. Cervical tissue sampling will be highly informative given that it is the
likely site of drug action. However, biopsies must be taken sparingly for several reasons:
they are uncomfortable to some and alter the healing process. Accordingly, two baseline
biopsies will be taken prior to randomization and ring insertion to confirm absence of study
drug and for PD studies. Subsequent biopsies for PK (pharmacokinetics) and PD
(pharmacodynamics) studies will be delayed until the ring is removed. Following TDF IVR
removal a third biopsy will be obtained for PK studies. Two cervical biopsies will be
obtained following placebo IVR removal for PD studies and to blind safety data. The study
will not be double-blinded because the TDF and placebo rings are not identical in appearance.
Therefore, the study clinician will be able to collect two biopsies from participants in the
placebo group and three biopsies from participants in the TDF ring group after ring removal.
In order to maintain participant blinding, all participants will be informed that two
biopsies will be taken before ring insertion and 2-3 biopsies will be taken after ring
removal. Paired biopsies will provide the best data, as it will avoid inter-individual
variability; both sets of cervical biopsies (pre- and post-IVR use) will be obtained during
the second half of the participant's menstrual cycle (cycle days 18-23), which is prior to
menses. Cervical biopsies will be obtained without local anesthetic. Participants may take
acetaminophen before and/or after the biopsies are collected if desired.

Primary Objective:

• Assess the safety of TDF IVR when used continuously for 14 days by healthy, HIV-uninfected,
sexually abstinent women, as compared with the placebo IVR

Secondary Objective:

• Examine systemic and genital tract PK of TDF release during and after 14 days of continuous
use of a reservoir-type IVR containing TDF

Exploratory Objectives:

- Evaluate the acceptability of and adherence to the study IVR

- Evaluate the PD during and after 14 days of continuous use of a reservoir-type IVR
containing TDF by measuring the antiviral activity of genital tract secretions ex vivo
and challenging biopsy tissue with virus

- Examine the impact of the study IVR on genital tract mucosal immunity and the vaginal
microbiota

- Examine the PK of TDF and TFV in rectal fluid during and after 14 days of continuous use
of a reservoir-type TDF IVR

- Evaluate mechanical properties and drug content following 14 days of continuous use of
reservoir-type IVRs

This is a single-site, two-arm, randomized single-blind, placebo-controlled trial. The study
population will include approximately 30 healthy, 18-45 year old women who are
HIV-uninfected, non-pregnant, sexually abstinent and using adequate contraception, as
described in the protocol. This sample size was chosen with the goal of having 12 women per
group complete the study and includes additional women to account for participants who may
not complete the study or are lost to follow-up. Only female volunteers will be recruited
since an IVR can only be used by women and the endpoints require genital sampling. To ensure
participants are protected from pregnancy during study participation, to minimize variability
among contraceptive methods, and to ensure adequate time between menses for ring use and
sample collection, all volunteers must be using low-dose combined hormonal contraceptive
pills. As this is a first-in-human trial of an intravaginal TDF ring, only healthy women will
be recruited and will be asked to wear a TDF or placebo IVR for 14 days.

The approximate time to complete study enrollment is expected to be 9 months. Two study
groups are planned. Both groups will be assigned to complete a total of 9 study visits:
(Screening [Visit 1], Enrollment [Visit 2], Days 0 [Visit 3], 1 [Visit 4], 3-5 [Visit 5], 7
[Visit 6], 14 [Visit 7], 16-18 [Visit 8], 21 [visit 9]). A Safety Call will also be conducted
on Day 10 of the study.

The two study groups are:

1. Reservoir-type TDF IVR group;

2. Reservoir-type polyurethane IVR group;

The expected duration for participants is approximately 5 - 10 weeks (including a screening
visit, an enrollment visit, two weeks of continuous IVR use, and one week following IVR
removal). Participants will undergo Visit 2 within 45 days of screening. No study data will
be collected after the Final Study/Early Termination Visit unless the participant is pregnant
at the Final Study/Early Termination Visit. Participants who have AEs (adverse events) at the
Final Study/Early Termination Visit that have not resolved or stabilized will be followed
beyond the Final Study/Early Termination Visit until a clinically acceptable resolution of
the AE(s) is confirmed and documented. Clinical acceptability of resolution will be
determined by the PL (Program Leader) in consultation with the Protocol Safety Review Team
(PSRT). Participants who are pregnant at the Final Study/Early Termination Visit may be
followed in accordance with procedures described in the study protocol.

Inclusion Criteria:

- General good health (by volunteer history and per investigator discretion) without any
clinically significant systemic disease (including, but not limited to significant
liver disease/hepatitis, gastrointestinal disease, kidney disease, thyroid disease,
osteoporosis or bone disease, and diabetes)

- Willing to give voluntary consent, sign an informed consent form and comply with study
procedures as required by the protocol

- HIV-uninfected based on testing performed by study staff during screening procedures

- Using low dose combined (estrogen and progesterone-containing) oral contraceptive
pills (does not include extended-cycle, 24 and 28-day active pill regimens). Per
participant report must be using this contraceptive method with no change in the prior
3 months and intending to use same method for the duration of study participation.

- Currently have a regular 28-day menstrual cycle on combined oral contraceptive pills.

- Normal Pap test at screening or appropriately documented history of Pap test and
completed follow-up of any abnormal pap tests consistent with American Congress of
Obstetricians and Gynecologists (ACOG) practice guidelines #99 and #109.

- Agrees not to participate in other research studies involving drugs, medical devices,
or vaginal products for the duration of study participation.

- Able and willing to refrain from inserting any non-study vaginal products or objects
into the vagina for the 48 hours prior to Visit 2 throughout the duration of the
study.

- Able and willing to abstain from oral, vaginal and anal sex for 48 hours prior to
Visit 2 throughout the duration of the study.

Exclusion Criteria:

Women must meet none of the following criteria prior to genital sampling at Visit 2:

- Known adverse reaction to polyurethane or to any components of the study product or
allergy to both silver nitrate and Monsel's solution.

- Hepatitis B infection (defined as positive hepatitis B surface antigen).

- Chronic, recurrent, and/or acute vulvar or vaginal symptoms (pain, irritation,
spotting, etc.).

- Known bleeding disorder that could lead to prolonged or continuous bleeding with
biopsy.

- Pregnant or intending to become pregnant during the period of study participation.

- Currently breastfeeding or having breastfed an infant in the last two months, or
planning to breastfeed during the course of the study.

- Menopause.

- History of unexplained or unresolved intermenstrual bleeding in the 3 months prior to
screening.

- History of gynecological procedures (including genital piercing) on the external
genitalia, vagina or cervix in the last 14 days.

- Hysterectomy.

- Use and/or anticipated use during the study period of an intravaginal or intrauterine
device.

- Systemic use in the last 2 weeks or anticipated use during the study period of any of
the following: corticosteroids, antibiotics, antifungals, antivirals, anticoagulants
or antiretrovirals.

- Grade 1 or higher laboratory abnormality, per the August 2009 update of the Division
of AIDS, National Institute of Allergy and Infectious Disease (DAIDS) Table for
Grading the Severity of Adverse Events (AEs).

- In the last six months, diagnosed with or treated for any sexually transmitted
infection (STI).

- Reproductive tract infection (RTI) or pelvic inflammatory disease (PID) requiring
treatment per current CDC (Center for Disease Control and Prevention) guidelines at
Screening or Enrollment.

- Positive test for Trichomonas vaginalis, Neisseria gonorrhea or Chlamydia trachomatis
at screening.

- Reactive test for syphilis at screening.

- At Screening or Enrollment, has a clinically apparent Grade 1 or higher pelvic exam
finding (observed by study clinician or designee) per the Division of AIDS Table for
Grading the Severity of Adult and Pediatric Adverse Events, Addendum 1, Female Genital
Grading Table for Use in Microbicide Studies.