Panacos Presents Data Showing Potent Activity of Drug Candidate PA-457

Panacos Pharmaceuticals has released detailed results from a positive Phase I/II clinical trial of its HIV drug candidate PA-457.

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. In the Phase I/II study, PA-457 was administered as a single oral dose to HIV-infected patients who were not on other therapy to determine the pharmacokinetics and antiviral activity of the compound. Single doses of up to 250 mg were tested and the level of HIV in the plasma, known as the viral load, was measured before and at intervals after treatment in each patient.

Following dosing, 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. Of particular interest were two subjects with pre-existing drug-resistance mutations in the highest dose groups, who both 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.