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

Sponsors: Division of AIDS, US National Institute of Allergy and Infectious Diseases (NIAID)
National Institutes of Health (NIH)

Protocol Summary: HPTN/MTN 035 was a four-arm, multi-center Phase II/IIb randomized controlled trial that aimed to determine the safety and effectiveness of two different candidate microbicides, BufferGel® and PRO 2000 (0.5% PRO 2000/5 Gel (P)) for the prevention of HIV in women. Participants were randomly assigned to one of four study groups: BufferGel, PRO 2000 gel, placebo gel, and no gel. The study enrolled its first participant in February 2005. Accrual was completed in July 2007 at which time a total of 3,100 sexually active HIV-negative women had been enrolled at seven sites in Malawi, South Africa, Zambia, Zimbabwe, and the United States.

Years: 2005 – 2008

Investigator: Z.M. Chirenje, MD, FRCOG

Locations: Spilhaus and Seke South CRSs


Completed Study


MacQueen KM, Namey E, Chilongozi DA, et al (2007) Community perspectives on care options for HIV prevention trial participants. AIDS Care. 2007 Apr; 19(4):554-60.

Abdool Karim SS, Richardson BA, Ramjee G, Hoffman IF, Chirenje ZM, et al. (2011) Safety and effectiveness of BufferGel and 0.5% PRO 2000 gel for prevention of HIV infection in women. AIDS; 25(7): 957-66.

Chirenje ZM, Masse BR, Maslankowski LA, et al. (2012) Utility of colposcopy in a phase 2 portion of a microbicide clinical trial of BufferGel and 0.5% PRO 2000 Gel. J Int AIDS Soc. 2012 Aug 27; 15(2):17376.

Dezzutti CS, Richardson BA, Marrazzo JM, et al. (2012) Mucosal Escherichia coli bactericidal activity and immune mediators are associated with HIV-1 seroconversion in women participating in the HPTN 035 trial. J Infect Dis. 2012 Dec 15; 206(12): 1931-35.

Richardson BA, Kelly C, Ramjee G, et al. (2013) Appropriateness of hydroxyethylcellulose gel as a placebo control in vaginal microbicide trials: a complarison of the two control arms of HPTN 035. J Acquir Immune Defic Syndr. 2013 May 1; 63(1): 120-5.

Gorbach PM, Kelly CW, Borgerding JA, et al. (2014) Effects of partnership change on microbicide gel adherence in a clinical trial (HPTN 035). AIDS Behav. 2014 May; 18(5): 855-61.

Guffey MB, Richardson B, Husnik M, et al (2014) HPTN 035 phase II/IIb randomised safety and effectiveness study of vaginal microbicides BufferGel and 0.5% PRO 2000 for the prevention of sexually transmitted infections in women. Sex Transm Infec. 2014 Aug; 90(5): 363-9.

Balkus JE, Brown ER, Hillier Sl, et al. (2016) Oral and injectable contraceptive use and HIV acquisition risk among women in four African countries: a secondary analysis of data from a microbicide trial. Contraception. 2016 Jan;93(1):25-31.

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