Panacos Pharmaceuticals, Inc. (NASDAQ:PANC), a biotechnology company dedicated to developing the next generation of antiviral therapeutic products, today announced preliminary results from the 300 mg cohort of a Phase 2b study of bevirimat (PA-457) in patients failing HIV therapy due to drug resistance. In this cohort, eight patients received 300 mg of bevirimat solution once daily and two patients received placebo for 14 days on top of their failing background regimen.