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RV144 Update at CROI

February 18, 2010
Presentation includes new data and research plans

COL Nelson Michael, MHRP Director, made a presentation today at the 17th Conference on Retroviruses and Opportunistic Infections (CROI 2010) in San Francisco, California. COL Michael showed some new data on risk factors and breakthrough infections. He also shared some ideas on the way forward for HIV vaccine development. 

MHRP has formed four scientific working groups to help guide recommendations on future research studies. A key consideration is how best to utilize the limited number of samples from RV144 to try to identify potential correlates of protection. MHRP is encouraging broad scientific participation, and is accepting scientific concept proposals from investigators who would like access to these specimens in their research. For additional information visit RV144 Research Concept Submissions.

Abstract:

RV 144 Update: Vaccination with ALVAC and AIDSVAX to Prevent HIV-1 Infection in Thai Adults 

Rerks-Ngarm, S., Pittisutthithum P., Nitayaphan, S., Kaewkungwal, J., Chiu, J., Paris, R., Premsri, N., Namwat, C., de Souza, M., Adams, E., Benenson, M., Gurunathan, S., Tartaglia, J., McNeil, J.G., Francis, D.P., Stablein, D., Birx, D.L., Chunsuttiwat, S., Khamboonruang, C., Thongcharoen, P., Robb, M.L., Michael, N.L., Kunasol, P., Kim, J.K., and the MOPH-TAVEG collaborators

Department of Disease Control, Ministry of Public Health (MOPH), Thailand: Vaccine Trials Centre, Faculty of Tropical Medicine, Mahidol University, Thailand; Thai Component, Armed Forces Research Institute of Medical Sciences (AFRIMS), Thailand; Data Management Unit, Faculty of Tropical Medicine, Mahidol University, Thailand; U.S. Army Medical Component, AFRIMS, Thailand; Division of AIDS, National Institutes of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), USA; sanofi pasteur, Swiftwater, PA, USA; Global Solutions for Infectious Diseases (GSID), S. San Francisco, CA, USA; EMMES Corporation, Rockville, MD, USA; Global AIDS Program, Centers for Disease Control, Atlanta, GA, USA

Background: Development of a safe and effective HIV vaccine is critical to pandemic control.

Methods: The study was a community-based, randomized, multicenter, double-blind, placebo-controlled efficacy trial of 4 canarypox ALVAC-HIV (vCP1521) priming injections and 2 AIDSVAX B/E gp120 subunit boosts in 16,402 healthy 18 to 30 year old Thai men and women, primarily at heterosexual risk, in Rayong and Chon Buri provinces, Thailand. Volunteers were monitored for the co-primary endpoints, HIV infection and early HIV-1 viremia at the end of the 6 month vaccination series and every 6 months thereafter for 3 years.

Results: 16,402 randomized subjects (including 7 later found to be HIV infected at baseline) were evaluated. Intent-to-treat (ITT) analysis showed a trend toward prevention of infection, vaccine efficacy (VE) 26.4% (p = 0.08; 95% CI -4.0, 47.9). Per protocol (PP) analysis of 12,452 persons showed a VE = 26.2% (p = 0.16, 95% CI -13.3, 51.9). Modified ITT (mITT) analysis of 16,395 HIV uninfected, randomized subjects showed VE 31.2% (p = 0.04, adjusted 95% CI 1.1, 51.2). Vaccination did not affect post-infection viremia or CD4+ T cell counts.

Conclusion: The ALVAC-HIV and AIDSVAX B/E prime-boost HIV vaccine regimen may reduce the risk of HIV infection in a community-based population in Thailand with largely heterosexual risk and did not affect post-infection viral load or CD4 count. While modest and likely without immediate public health benefit, the results offer insight for future research. A comprehensive approach for the elucidation of a correlate/surrogate of protection and plans for follow-on clinical studies will be presented.