Atazanavir.

Atazanavir is a novel azapeptide protease inhibitor with high specificity for, and activity against, HIV-1 protease. The resistance profile of atazanavir is distinct, with an I50 L protease substitution appearing to be the signature mutation. Atazanavir was not associated with increases in total cholesterol, low density lipoprotein-cholesterol or triglyceride levels after 108 weeks. Atazanavir has a pharmacokinetic profile that allows for once-daily oral administration. It is a moderate inhibitor of hepatic cytochrome P450 enzymes and interacts with several drugs. In combination with stavudine plus didanosine, atazanavir 200, 400 or 500 mg once daily produced a rapid and sustained reduction from baseline in viral load of 2.57, 2.42 and 2.53 log(10) copies/mL, respectively, in treatment-naive patients after 48 weeks, compared with a decrease of 2.33 log(10) copies/mL with nelfinavir 750 mg three times daily. Nausea was the most clinically relevant adverse event reported in patients receiving atazanavir-based regimens.