A Phase II Safety and Immunogenicity Trial of Live Recombinant Canarypox ALVAC-HIV vCP205 With or Without HIV-1 SF-2 RGP120 in HIV-1 Uninfected Adult Volunteers

To expand the available data regarding the safety and immunogenicity of 2 HIV-1 vaccine strategies: canarypox vector vCP205, or vCP205 with SF-2 rgp120. \[AS PER AMENDMENT 7/2/98: To obtain immunogenicity and safety data on gp120 subunits that may induce enhanced neutralizing antibody response to primary isolates of HIV-1 in the context of previous immunization with a canarypox vector expressing HIV antigens (vCP205). To evaluate cytotoxic T lymphocyte responses at 1 and 2 years after initial vaccination with vCP205 plus rgp120 SF-2 or vCP205 alone.\] In previous ALVAC vCP205/SF-2 rgp 120 studies, patients have developed antibodies that neutralize homologous laboratory strains; over 50% of patients have developed CD8+ cytotoxic T-lymphocyte responses to HIV env and gag epitopes at some point in the study. This Phase II study seeks to confirm these results among persons at lower or higher risk for HIV infection with a new lot of ALVAC vCP205, at a dose that is suitable for potential large-scale trials. \[AS PER AMENDMENT 7/2/98: Addition of AIDSVAX B/B or AIDSVAX B/E boosts starting at least 12 months after receiving rgp120 or ALVAC vaccines may induce enhanced neutralizing antibody response as deemed from prior studies and thus is planned as "follow-up" therapy.\]

In previous ALVAC vCP205/SF-2 rgp 120 studies, patients have developed antibodies that neutralize homologous laboratory strains; over 50% of patients have developed CD8+ cytotoxic T-lymphocyte responses to HIV env and gag epitopes at some point in the study. This Phase II study seeks to confirm these results among persons at lower or higher risk for HIV infection with a new lot of ALVAC vCP205, at a dose that is suitable for potential large-scale trials. \[AS PER AMENDMENT 7/2/98: Addition of AIDSVAX B/B or AIDSVAX B/E boosts starting at least 12 months after receiving rgp120 or ALVAC vaccines may induce enhanced neutralizing antibody response as deemed from prior studies and thus is planned as "follow-up" therapy.\] Volunteers are recruited and screened; those who are enrolled are then stratified by their risk status into 2 groups: individuals having lower-risk behavior for HIV and individuals having higher-risk behavior for HIV. Volunteers are then randomly assigned to arm A, B, or C and receive immunizations at months 0, 1, 3, and 6 as follows: Group A- ALVAC vCP205 plus SF-2 rgp120 in MF59. Group B- ALVAC vCP205 plus saline placebo. Group C- Placebo-ALVAC plus saline placebo. \[AS PER AMENDMENT 7/2/98: Beginning 12-18 months after initial vaccination, then 2, 6, and 12 months later, 10 volunteers from group A receive saline placebo, while 50 volunteers each from groups B and C are rerandomized within their respective groups, and are treated as follows. Group B (subgroup 1) - AIDSVAX B/B. Group B (subgroup 2) - AIDSVAX B/E. Group B (subgroup 3) - alum placebo. Group C (subgroup 1) - AIDSVAX B/B. Group C (subgroup 2) - AIDSVAX B/E. Group C (subgroup 3) - alum placebo.\] Volunteers are followed for 2 years and are tested for humoral immune response to HIV-1. Neutralizing activity to HIV-1 is performed on a subset of volunteers monitored for CTL response. \[AS PER AMENDMENT 7/2/98: Volunteers receiving AIDSVAX B/B and AIDSVAX B/E will additionally be studied for formation of various neutralizing antibodies and parameters of cellular immunity.\] \[AS PER AMENDMENT 4/30/99: Because the subunit boosts that were added in version 3.0 are not available, the subunit boost portion of version 3.0 is cancelled.\]