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HPTN 035 phase II/IIb randomised safety and effectiveness study of the vaginal microbicides BufferGel and 0.5% PRO 2000 for the prevention of sexually transmitted infections in women
  1. M Bradford Guffey1,2,
  2. Barbra Richardson3,4,
  3. Marla Husnik3,
  4. Bonus Makanani5,
  5. David Chilongozi6,
  6. Elmer Yu7,
  7. Gita Ramjee8,
  8. Nyaradzo Mgodi9,
  9. Kailazarid Gomez10,
  10. Sharon L Hillier11,
  11. Salim Abdool Karim12,
  12. on behalf of the HIV Prevention Trials Network (HPTN) 035 Study Team
  1. 1Departments of Medicine and Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama, USA
  2. 2Centre for Infectious Disease Research in Zambia, Lusaka, Zambia
  3. 3Fred Hutchinson Cancer Research Center, Seattle, Washington, USA
  4. 4Department of Biostatistics, University of Washington, Seattle, Washington, USA
  5. 5Department of Obstetrics and Gynaecology, University of Malawi College of Medicine, Blantyre, Malawi
  6. 6University of North Carolina Project, Lilongwe, Malawi
  7. 7Department of Psychiatry, University of Pennsylvania, Philadelphia, Pensylvania, USA
  8. 8HIV Prevention Research Unit, South African Medical Research Council, Durban, KwaZulu-Natal, South Africa
  9. 9Department of Obstetrics and Gynaecology, University of Zimbabwe-University of California San Francisco Collaborative Research Programme, Belgravia, Harare, Zimbabwe
  10. 10FHI 360, Science Facilitation, Research Triangle Park, North Carolina, USA
  11. 11Department of Obstetrics, Gynecology and Reproductive Sciences, Magee-Womens Research Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
  12. 12University of KwaZulu-Natal, CAPRISA, Durban, KwaZulu-Natal, South Africa
  1. Correspondence to Dr M Bradford Guffey, Centre for Infectious Disease Research in Zambia, University of Alabama at Birmingham, 5032 Great North Road, P.O Box 34681, Lusaka 10101, Zambia; guffey{at}


Objectives To estimate the effectiveness of candidate microbicides BufferGel and 0.5% PRO 2000 Gel (P) (PRO 2000) for prevention of non-ulcerative sexually transmitted infections (STIs).

Methods Between 2005 and 2007, 3099 women were enrolled in HIV Prevention Trials Network (HPTN) protocol 035, a phase II/IIb evaluation of the safety and effectiveness of BufferGel and PRO 2000 for prevention of STIs, including Neisseria gonorrhoeae (NG), Chlamydia trachomatis (CT) and Trichomonas vaginalis (TV). Incidences of STIs were determined by study arm, and HRs of BufferGel and PRO 2000 versus placebo gel or no gel control groups were computed using discrete time Andersen-Gill proportional hazards model.

Results The overall incidence rates were 1.6/100 person-years at risk (PYAR) for NG, 3.9/100 PYAR for CT and 15.3/100 PYAR for TV. For BufferGel versus placebo gel, HRs were 0.99 (95% CI 0.49 to 2.00), 1.00 (95% CI 0.64 to 1.57) and 0.95 (95% CI 0.71 to 1.25) for prevention of NG, CT and TV, respectively. For PRO 2000, HRs were 1.66 (95% CI 0.90 to 3.06), 1.16 (95% CI 0.76 to 1.79) and 1.18 (95% CI 0.90 to 1.53) for prevention of NG, CT and TV, respectively.

Conclusions The incidence of STIs was high during HIV Prevention Trials Network 035 despite provision of free condoms and comprehensive risk-reduction counselling, highlighting the need for effective STI prevention programmes in this population. Unfortunately, candidate microbicides BufferGel and PRO2000 had no protective effect against gonorrhoea, chlamydia or trichomoniasis.

Trial registration number NCT00074425.


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