Analysis of the Phase I/II clinical trial of HIV drug candidate PA-457

V.I. Technologies (Vitex) and collaborators at the University at Buffalo's School of Pharmacy and Pharmaceutical Sciences, Buffalo, NY, today presented a detailed analysis of the Phase I/II clinical trial of its HIV drug candidate PA-457 at the 3rd International AIDS Society (IAS) Conference on HIV Pathogenesis and Treatment in Rio de Janeiro, Brazil.

PA-457 is the first in a new class of HIV drugs called Maturation Inhibitors, with broad activity against HIV, including strains resistant to currently approved drugs, the most common cause of HIV treatment failure.

The key results of this Phase I/II single dose study were reported previously at the 12th Conference on Retroviruses and Opportunistic Infections in February 2005. PA-457 was administered as a single oral dose of up to 250mg to HIV-infected patients who were not on other therapy. Following administration, patients in the highest dose groups had reductions in viral load of up to approximately 0.7 log10 and mean reductions compared to the placebo group of approximately 0.4 log10 that were statistically significant. In this study, two subjects with pre-existing drug-resistance mutations exhibited greater than 0.5 log10 reductions from baseline following PA-457 treatment. PA-457 was well tolerated at all dose levels in the Phase I/II study.

At the IAS Conference, a more complete analysis of the data was provided, including generation of a model allowing detailed examination of the correlation between PA-457's pharmacokinetics and the drug's antiviral effect. This analysis confirmed and extended the findings presented previously that a single dose of PA-457 was associated with a dose-related reduction in viral load in HIV-infected patients. Researchers on the study included Drs. Abayomi B. Ogundele, Patrick F. Smith and Alan Forrest of The University at Buffalo and Dr. David E. Martin of Vitex.