Randomized, double-blind, placebo-controlled efficacy trial of a bivalent recombinant glycoprotein 120 HIV-1 vaccine among injection drug users in Bangkok, Thailand.
BACKGROUND
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
Despite the successful completion of this efficacy trial, the vaccine did not prevent HIV-1 infection or delay HIV-1 disease progression.
Pitisuttithum
Punnee
P
Department of Clinical Tropical Medicine, Mahidol University, Bangkok 10400, Thailand. punneep@dmc.inet.co.th
Gilbert
Peter
P
Gurwith
Marc
M
Heyward
William
W
Martin
Michael
M
van Griensven
Fritz
F
Hu
Dale
D
Tappero
Jordan W
JW
Choopanya
Kachit
K
D016915:AIDS Vaccines / Q000008:administration & dosage*; D000163:Acquired Immunodeficiency Syndrome / Q000209:etiology; D000328:Adult; D018791:CD4 Lymphocyte Count; D004311:Double-Blind Method; D005260:Female; D015699:HIV Envelope Protein gp120 / Q000235:genetics / Q000276:immunology*; D015658:HIV Infections / Q000150:complications / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D015497:HIV-1 / Q000276:immunology / Q000302:isolation & purification; D006801:Humans; D015994:Incidence; D007273:Injections, Intramuscular; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000276:immunology; D015819:Substance Abuse, Intravenous; D013785:Thailand / Q000453:epidemiology; D014611:Vaccination; D019562:Viral Load
D016915:AIDS Vaccines; D015699:HIV Envelope Protein gp120; D011994:Recombinant Proteins