AEGiS-11IAC: Active immunization of patients with HIV infection: a controlled study of the effect of VaxSyn on progression of immune deficiency.

11th International AIDS Conference

Vancouver, British Columbia — July 7-12, 1996

Active immunization of patients with HIV infection: a controlled study of the effect of VaxSyn on progression of immune deficiency.

Int Conf AIDS 1996 Jul 7-12; 11:222 (abstract no. Tu.A.274)
Tsoukas CM, Raboud J, Schlech W, Thomas R, Fong I, Rachlis A, Gill J, Montaner J, Lee S, Freedman J, Poon MC, Lafreniere R, Cassol S, Djurdjev O, Smith G; The Canadian HIV Trials Network, Quebec, Canada. Fax: 514-937-1424.

OBJECTIVE: To describe the effect of recombinant HIV envelope precursor protein VaxSyn (rgp 160) on the course of HIV disease during a three year controlled study of HIV-infected asymptomatic individuals.

METHODS: 280 patients with CD4 counts greater than 500 cells/mm3 were enrolled in a double blinded, randomised, controlled, multicentre study. They received 320 micrograms of rgp 160 or placebo intramuscularly on days 0, 30, 60, 90, 180 and every 120 days thereafter. At two years, those on placebo were treated with rgp 160 on the same dose and injection schedule as those on the initial active treatment arm. Hematologic and biochemical tests, cellular and humoral immune responses, as well as HIV viral assessments (on a subset of patients) were carried out.

RESULTS: At enrollment, the median CD4 count was 662 cells/mm3 (range 474-1638) all patients were asymptomatic, 71% were in CDC Class II and 29% in CDC Class III. 231 (83%) of the patients completed 2 years of follow-up; 186 (67%) completed all 3 years. The mean declines in CD4 counts at 2 years of follow-up were 155 and 111 cells/mm3 in the VaxSyn and placebo groups respectively (p=.08). The annual rates of decline in CD4 counts in the VaxSyn and placebo groups were 69 cells/mm3 and 72 cells/mm3, respectively (p=.30). Among the patients on the placebo arm, the change in rate of decline in CD4 counts from the placebo phase to the active drug phase was 15 cells/mm3 (90% CI=(-416,263)). There was no significant difference in rates of change over time (p=.22). Only 12 AIDS-defining events were observed during the study period (5 on the VaxSyn arm and 7 on the placebo arm). One of the seven patients in the placebo group with an ADI died. An additional patient in the VaxSyn group died.

CONCLUSION: VaxSyn was well tolerated and free of significant toxicity. Patients treated with rgp 160 had similar declines in CD4 counts during the study period as patients on placebo. Patients randomized to placebo for the first phase of the study had similar declines on the placebo and active drug phases of the study.

Keywords: AEGIS, HIV Infections, CD4 Lymphocyte Count, AIDS Vaccines, Acquired Immunodeficiency Syndrome, Vaccination, Placebos, Anti-HIV Agents, Double-Blind Method, VaxSyn HIV-1 (gp160) vaccine, Human, ICA11

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