AEGiS-15IAC: Phase III trial of HIV prime-boost vaccine combination in Thailand.

15th International AIDS Conference

Bangkok, Thailand - July 11-16, 2004

Phase III trial of HIV prime-boost vaccine combination in Thailand.

Int Conf AIDS 2004 Jul 11-16; 15:(abstract no. ThOrC1428)

Rerks-Ngarm S, Pittisutthithum P, Nitayaphan S, Brown AE, Kitayaporn D, Gurunathan S, Heyward W, McNeil J
Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand

BACKGROUND: The world's first community-based, phase III HIV vaccine trial began in Thailand in late 2003. This is being carried out through the infrastructure of the Ministry of Public Health, augmented by Mahidol University and supported by the Armed Forces Research Institute of Medical Sciences. Objectives: determine if this prime-boost vaccine strategy 1) prevents infection, 2) alters disease course in vaccinees who become infected, and 3) is safe. Vaccines were designed specifically for the predominant circulating HIVs in Thailand (subtypes E and B). Prime: a recombinant canarypox ALVAC-HIV (vCP1521) with a subtype B gag/pro and gp41, and subtype E gp120 (R5) gene insertions (Aventis Pasteur). Boost: AIDSVAXOgp120 B/E, monomers of gp120 B (X4) + gp120 E (R5) with alum (VaxGen).

METHODS: 16,000 HIV-negative adult Thais, screened and enrolled through the health care system of the Ministry of Public Health. Study design: randomized, placebo-controlled, double-blind phase III trial. Immunization is intramuscular over 6 months with a 3-year follow-up period.

RESULTS: Clinical, laboratory & data system infrastructures have been built, qualified and validated; more than 400 staff trained, counseling and treatment networks strengthened, and communities engaged. HIV prevalence in volunteers assessed in a screening protocol was ~3%. During the initial 3-month phase-in period of the trial, more than 500 volunteers were enrolled.

CONCLUSIONS: With focus on a low-incidence, community-based population, the trial size is large, logistics very demanding and community engagement crucial.

Keywords: AEGIS, HIV, Acquired Immunodeficiency Syndrome, Thailand, HIV Seropositivity, Clinical Trials, Phase III, AIDS Vaccines, HIV Envelope Protein gp120, HIV Infections, HIV Antibodies, HIV Seronegativity, HIV Antigens, Double-Blind Method, Counseling, Adult, immunology

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ThOrC1428