POLYDEX HALTS MICROBICIDE TRIAL AFTER INCREASED HIV RISK SEEN

Polydex Pharmaceuticals has reported that that Conrad, a reproductive health research organization, has halted a Phase III clinical trial of Ushercell -- a cellulose sulfate topical microbicide gel being tested for HIV prevention in women -- because preliminary results at some trial sites indicated that cellulose sulfate could lead to potential increased risk of HIV infection in women who use the compound. The trial was being conducted in South Africa, Benin, Uganda and India.

Additionally, Family Health International has halted a second Phase III cellulose sulfate trial in Nigeria. Although investigators did not detect an increased HIV risk associated with cellulose sulfate, the decision was made as a precautionary measure, given the preliminary results from the Conrad trial. Cellulose sulfate was one of four microbicides being tested in effectiveness trials for prevention of HIV and other sexually transmitted infections.

Polydex does not know why use of cellulose sulfate was associated with an increased risk of HIV infection in the Conrad trial. The independent data monitoring committee will conduct a detailed review of the data to better understand the findings and help determine any implications for other microbicide studies.

"Ushercell has shown a consistent safety profile up to this point, having undergone 11 rigorous clinical safety and contraceptive trials involving more than 500 participants before entering the HIV prevention trial," President and CEO of Conrad George Usher said. "We will continue to evaluate Ushercell's attributes including its potential use as a contraceptive product."

The Conrad Phase III study began in July 2005. Half of the participating women were given cellulose sulfate, and half a placebo gel, in a double-blind, randomized trial. All participants received HIV prevention counseling and free condoms. Participants received regular testing and treatment for sexually transmitted infections.