Randomized, DoubleΓÇÉBlind, PlaceboΓÇÉControlled Efficacy Trial of a Bivalent Recombinant Glycoprotein 120 HIVΓÇÉ1 Vaccine among Injection Drug Users in Bangkok, Thailand

Department of Clinical Tropical Medicine, Mahidol University, Bangkok 10400, Thailand.
The Journal of Infectious Diseases (Impact Factor: 6). 01/2007; 194(12):1661-71. DOI: 10.1086/508748
Source: PubMed


In Thailand, phase 1/2 trials of monovalent subtype B and bivalent subtype B/E (CRF01_AE) recombinant glycoprotein 120 human immunodeficiency virus type 1 (HIV-1) vaccines were successfully conducted from 1995 to 1998, prompting the first HIV-1 vaccine efficacy trial in Asia.
This randomized, double-blind, placebo-controlled efficacy trial of AIDSVAX B/E (VaxGen), which included 36-months of follow-up, was conducted among injection drug users (IDUs) in Bangkok, Thailand. The primary end point was HIV-1 infection; secondary end points included plasma HIV-1 load, CD4 cell count, onset of acquired immunodeficiency syndrome-defining conditions, and initiation of antiretroviral therapy.
A total of 2546 IDUs were enrolled between March 1999 and August 2000; the median age was 26 years, and 93.4% were men. The overall HIV-1 incidence was 3.4 infections/100 person-years (95% confidence interval [CI], 3.0-3.9 infections/100 person-years), and the cumulative incidence was 8.4%. There were no differences between the vaccine and placebo arms. HIV-1 subtype E (83 vaccine and 81 placebo recipients) accounted for 77% of infections. Vaccine efficacy was estimated at 0.1% (95% CI, -30.8% to 23.8%; P=.99, log-rank test). No statistically significant effects of the vaccine on secondary end points were observed.
Despite the successful completion of this efficacy trial, the vaccine did not prevent HIV-1 infection or delay HIV-1 disease progression.

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Available from: Punnee Pitisuttithum, Sep 26, 2014
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    • "The vaccine was changed to AIDSVAX B/E to reflect common virus subgroups as former one (Pitisuttithum et al., 2006). Again, the results of the study showed that the vaccine did not prevent HIV infection nor did it delay disease progression (Pitisuttithum et al., 2006). Given the slow progress in developing effective vaccines using traditional approaches, novel vaccine technologies, which include plasmid DNA vaccines and live recombinant vectors, are also being investigated (Barouch, 2008). "
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    • "It is widely accepted that an effective prophylactic vaccine against HIV-1 should elicit neutralizing antibodies (Nabs) that, if present at the time of transmission, could block HIV acquisition. However, all vaccine candidates based on the induction of neutralizing antibodies failed to induce Nabs and also failed large-scale efficacy phase III trials [1] [2]. Therefore, the HIV prophylactic vaccine research shifted to evaluate vaccine candidates capable of inducing cell-mediated immune responses (CMI). "
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