HIV gags on PA-457

HIV drugs currently target three viral proteins, but Panacos Pharmaceuticals Inc. is hoping to up the tally with its PA-457, a compound that interferes with the formation of infectious viral particles by inhibiting the production of HIV capsid antigen.

Despite its activity against a novel target, the genesis of PA-457 was not target-based drug discovery. Instead, Panacos (Gaithersburg, Md.) started with betulinic acid, a weak HIV inhibitor, and generated PA-457 through medicinal chemistry. ...