HPTN 035

Phase II/IIb Safety and Effectiveness Study of the Vaginal Microbicides BufferGel and 0.5% PRO2000/5 Gel (P) for the Prevention of HIV Infection in Women

Study Summary

What was HPTN 035?

A Phase II/IIb, four-arm, multisite, randomized controlled trial to evaluate the safety and effectiveness of two candidate vaginal microbicides, BufferGel and 0.5% PRO 2000/5 Gel (P), for the prevention of HIV infection in women.

Who participated in the study?

3,099 sexually active HIV-uninfected women from the following study sites: Blantyre, Malawi; Lilongwe, Malawi;; Durban, South Africa; Hlabisa, South Africa; Lusaka, Zambia; Harare, Zimbabwe; and Philadelphia, PA, USA

What happened during the study?

Study participants were randomly assigned to one of four groups: BufferGel, PRO 2000 Gel, placebo gel, and no gel. The Phase II portion of the study involved intensive safety evaluations among the first 799 women enrolled in the study. The Phase IIb portion involved the first 799 women and an additional 2,300 women.

Results

PRO 2000 gel (0.5 percent dose) was 30 percent effective.

During the course of the study, 194 women acquired HIV. Of this total, 36 HIV infections occurred among participants who used PRO 2000, while 54 infections occurred among participants who used BufferGel, 51 infections occurred among participants who used placebo gel, and 53 infections occurred among participants who used no gel. Using these data as a basis for determining the effectiveness of the two candidate microbicides, the researchers found that BufferGel had no effect on HIV infection and that PRO 2000 had a 30 percent level of effectiveness in preventing HIV infection. Both gels were found to be safe.

Study Details

Protocol Status: Concluded
Study Purpose:

To determine the safety and effectiveness of two candidate vaginal microbicides: BufferGel and 0.5% PRO 2000 Gel (P).

Study Design:

Phase II/IIb, four-arm, multisite, randomized controlled trial comparing BufferGel and 0.5% PRO 2000/5 Gel (P) with a placebo gel and with no gel. The three study gel arms were double-blinded. The Phase II portion of the study was conducted as an uninterrupted lead-in to the Phase IIb portion. Each study participant completed approximately 12-30 months of follow-up (20 monts on average).

Study Population:

Sexually active HIV-uninfected women from the following study sites: Blantyre, Malawi; Lilongwe, Malawi;; Durban, South Africa; Hlabisa, South Africa; Lusaka, Zambia; Harare, Zimbabwe; Philadelphia, PA, USA

Study Size:

3099 women

Study Duration:

February 2005 through September 2008

Treatment Regimen:

Participants assigned to the three study gel groups were instructed to apply a single dose of their randomly assigned product − BufferGel, 0.5% PRO 2000/5 Gel (P), or placebo gel − intravaginally up to 60 minutes before each act of vaginal intercourse using single-use, pre-filled applicators. Participants in all four groups received ongoing HIV risk reduction counseling, condoms, and diagnosis and treatment of sexually transmitted diseases.

Primary Objectives:

To evaluate the safety of BufferGel and 0.5% PRO2000/5 Gel (P) when applied intravaginally by women at risk for sexually-transmitted HIV infection.

To estimate the effectiveness of BufferGel and 0.5% PRO 2000/5 Gel (P) in preventing HIV infection among at-risk women.

Secondary Objectives:

To estimate the effectiveness of BufferGel and 0.5% PRO 2000/5 Gel (P) in preventing the following among women at risk for sexually-transmitted HIV infection: bacterial vaginosis, chlamydia infection, genital ulcer disease, gonorrhea infection, herpes simplex virus-2 infection, pregnancy, syphilis infection, trichomoniasis.

To assess the acceptability of BufferGel and 0.5% PRO 2000 Gel (P) for use as a vaginal microbicide.

Key Study Personnel

Salim Abdool Karim, Protocol Chair
Missy Cianciola, SDMC Protocol Specialist
Kailazarid Gomez, CORE Protocol Specialist
Irving F. Hoffman, Protocol Co-Chair
Muzala Kapina, Protocol Co-Chair
Lisa Maslankowski, Protocol Co-Chair
Nancy Padian, Protocol Co-Chair
Gita Ramjee, Protocol Co-Chair
Lydia Soto-Torres, DAIDS Medical Officer
Taha Taha, Protocol Co-Chair
Sheryl Zwerski, DAIDS Medical Officer