ADVANCING AIDSVAX(TM) TO PHASE-3 - SAFETY, IMMUNOGENICITY, AND PLANS FOR PHASE-3

AIDSVAX(TM) (VaxGen, Inc., South San Francisco, CA), a possible vaccin e to protect against human immunodeficiency virus type 1 (HIV-1) infec tion, is being tested for efficacy in phase 3 studies. It has been tes ted for potential efficacy in chimpanzees, and tested for safety and i mmunogenicity in human clinical studies. Four candidate vaccines, each with a different envelope protein antigen or combination of antigens, have been produced in alum formulations. In both design and clinical testing, AIDSVAX(TM) has an excellent safety profile, Because these hi ghly purified proteins were prepared using recombinant DNA technology, there is no possibility of these vaccines causing HIV infection. Havi ng been administered to over 1200 people, the only side effects attrib utable to AIDSVAX(TM) have been local pain and inflammation at the inj ection site, After immunization, essentially all recipients developed a robust antibody response, including binding and neutralizing antibod ies. The neutralizing antibodies peaked after a 12-month boost. Excell ent memory is induced. Two phase 3 trials of two bivalent formulations will evaluate their efficacy. One trial will use a bivalent subtype B formulation. This trial in North America will involve 5000 men who ha ve sex with men and heterosexual women at high risk, The other study m ill use a bivalent subtype B/subtype E formulation. This trial in Thai land and will involve 2500 intravenous drug users. Both studies will b e randomized, double-blinded and placebo controlled. The volunteers wi ll be followed for 3 years, The end points of the studies are infectio n, as defined by seroconversion to standard diagnostic tests, and vira l load, as defined by commercial polymerase chain reaction (PCR) tests .