ALVAC HIV vaccine: Additional Phase III data

Additional data from the U.S. Army Surgeon General-sponsored, double-blind, Thai Phase III RV144 trial in 16,402 adult volunteers showed that Sanofi Pasteur S.A.'s ALVAC HIV vaccine boosted by the AIDSVAX B/E gp120 vaccine missed the co-primary endpoints in the intent-to-treat (ITT) and per protocol (PP) populations. The regimen lowered the rate of HIV infection by 26.4% vs. placebo at 3 years in the ITT population, which included all 16,402 subjects who underwent randomization (56 vs. 76 infections, p=0.08). The regimen lowered the rate of HIV infection by 26.2% in the PP population, which included 12,542 subjects who received the entire series of vaccinations within the defined time period, who remained eligible to participate in the study and who did not have HIV infection at the time of the fourth vaccination (36 vs. 50 infections, p=0.16). Vaccination did not affect viral load, the second co-primary endpoint, or CD4+ count in subjects with HIV infection. Data were reported at the AIDS Vaccine 2009 meeting in Paris and published in the New England Journal of Medicine.

In September, data were reported from the modified intent-to-treat (mITT) population showing that the vaccine and booster significantly lowered the rate of HIV infection by 31.2% vs. placebo at 3 years (51 vs. 74 infections, p=0.04). The mITT population (n=16,395) excluded 7 subjects who were found to have HIV-1 infection at baseline (see BioCentury, Sept. 28). The authors said, "Taken together, these data are consistent with a modest protective effect of vaccine in the study." ...