Efficacy testing of recombinant human immunodeficiency virus (HIV) gp160 as a therapeutic vaccine in early-stage HIV-1-infected volunteers

A phase II efficacy trial was conducted with recombinant human immunodeficiency virus (HIV) type 1 envelope glycoprotein gp160 (rgp160) in 608 HIV-infected, asymptomatic volunteers with CD4(+) cell counts >400 cells/mm(3). During a 5-year study, volunteers received a 6-shot primary series of immunizations with either rgp160 or placebo over 6 months, followed by booster immunizations every 2 months. Repeated vaccination with rgp160 was safe and persistently immunogenic. Adequate follow-up and acquisition of endpoints allowed for definitive interpretation of the trial results, There was no evidence that rgp160 has efficacy as a therapeutic vaccine in early-stage HIV infection, as measured at primary endpoints (50% decline in CD4(+) cell count or disease progression to Waiter Reed stage 4, 5, or 6) or secondary endpoints. A transient improvement was seen in the secondary CD4 endpoint for the vaccination compared with the placebo arm, but this did not translate into improved clinical outcome.