A Phase I Clinical Trial to Evaluate:Part A. The Safety and Immunogenicity of Two Dose Levels of SF-2 gp120 (CHO) With or Without MTP-PE Adjuvant in the MF59 Emulsion Part B. The Safety and Immunogenicity of Five Monthly Doses of 50 mcg gp120 Protein in MF59 Emulsion (Without MTP-PE) Versus the Emulsion Control

One experimental AIDS vaccine is the gp120 vaccine. The HIV envelope glycoprotein 120 is manufactured through recombinant DNA technology and used as an immunogen. Antibodies directed against gp120 can neutralize HIV-1, and gp120 can also stimulate certain types of cell-mediated immune responses. Because many immunogens, including candidate HIV vaccines, may evoke relatively weak immune responses, the use of adjuvants, or substances that augment immune responses to vaccines, is of interest. MTP-PE/MF59, composed of the immunomodulator MTP-PE combined with MF59 emulsion, appears to be a promising adjuvant and has been selected for studies with the gp120 vaccine.

In Part A, 32 volunteers (eight on each of four treatment arms) are randomized to receive one of two doses (15 or 50 mcg) of gp120 vaccine with either MTP-PE/MF59 adjuvant emulsion or MF59 emulsion alone. The volunteers receive three IM injections at 0, 1, and 6 months. In Part B, 16 female volunteers (eight on each of two treatment arms) are randomized to receive either MF59 emulsion alone (placebo) or MF59 emulsion plus gp120 vaccine (50 mcg). Volunteers receive five IM injections at monthly intervals.