A Phase I Multicenter Study of the Safety and Immunogenicity of MN rgp120/HIV-1 Vaccine Given Either Alone or in Combination With IIIB rgp120/HIV-1 Vaccine in Healthy Adult Subjects (NOTE: Original Study Extended ONLY for Patients Previously Enrolled on VEU 009)

Recent studies suggest that immunity to the HIV-1 rgp120 protein may prevent primary infection. MN rgp120 vaccine and IIIB rgp120 vaccine are both prepared by recombinant DNA technology. Because the two vaccines are derived from distinct HIV-1 strains, they may elicit some immunologic responses that differ. Unlike IIIB rgp120 vaccine, the MN rgp120 vaccine has not yet been evaluated in humans, although it is expected that the MN type will result in similar safety and immunogenicity as the IIIB type. AMENDED 10/1/93: Selected patients on VEU 009 who received four previous injections will receive three additional injections on the study extension (VEU 009X), administered at weeks 72, 76, and 104. Patients who received 300 or 600 mcg MN rgp120 vaccine (eight patients per dosage) in the original portion of the study will be randomized to receive either 300 mcg MN rgp120 or 300 mcg IIIB rgp120 vaccine. Eight patients who previously received the MN/IIIB combination will again receive 300 mcg of both vaccines. Additionally, six patients who received placebo in the original portion will receive 300 mcg IIIB rgp120 vaccine. There will be nine clinic visits required for the study extension. ORIGINAL DESIGN: Fifty-seven adult subjects will be randomized to receive MN rgp120 vaccine at one of three dosages (100, 300, or 600 mcg), or 300 mcg MN rgp120 vaccine given concurrently with 300 mcg IIIB rgp120 vaccine, or placebo. Twelve subjects will be entered onto each of the four vaccine arms, and nine subjects will be entered on the placebo arm. Immunizations (or placebo injections) are given intramuscularly at 0, 4, 24, and 48 weeks. Subjects are followed for 15 months after the first immunization.