Context: Despite enormous improvements achieved through the use of antiretroviral therapies (ARTs), the risk for eventual human immunodeficiency virus (HIV) disease progression remains high. Agents that enhance the immunologic mechanism for viral recognition might reduce disease progression.
Objective: To determine whether the addition of HIV-1 Immunogen would confer added clinical efficacy to that achievable by ARTs.
Design and setting: Multicenter, double-blind, placebo-controlled, randomized trial beginning March 1996 and ending May 1999 conducted at 77 centers in the United States providing primary care or referral care for persons infected with HIV.
Patients: Adults infected with HIV who have baseline CD4 cell counts between 300 x 10(6)/L and 549 x 10(6)/L without prior acquired immunodeficiency syndrome-defining conditions receiving stable ART (or no therapy) were screened and 2527 were randomized.
Interventions: Ten units of HIV-1 Immunogen, derived from a Zairian HIV isolate, inactivated and formulated with incomplete Freund adjuvant, was administered intramuscularly every 12 weeks. The placebo was incomplete Freund adjuvant. Changes in ARTs were allowed.
Main outcome measures: HIV progression-free survival; secondary end points included overall survival, changes in HIV RNA, CD4 cell counts, CD4 percentage, body weight, and immunogenicity.
Results: The overall event rate was 1.8 per 100 person-years of follow-up. Fifty-three subjects developed clinical progression in each treatment group (relative risk [RR], 0.97; 95% confidence interval [CI], 0.66-1.42; P =.89). There were 19 and 23 deaths in the placebo and HIV-1 Immunogen groups, respectively (RR, 0.81; 95% CI, 0.44-1. 48; P =.49). There were no statistically significant differences between the groups with respect to changes in HIV RNA (P =.59), CD4 percentage (P =.63), or body weight (P =.89). Subjects in the HIV-1 Immunogen group had an increase in average CD4 cell count of approximately 10 x 10(6)/L greater than the placebo group (P =.02).
Conclusion: HIV-1 Immunogen with unrestricted ART failed to demonstrate an increase in HIV progression-free survival. JAMA. 2000;284:2193-2202.