Vertex Pharmaceuticals Incorporated announced that the Food and Drug Administration (FDA) has granted marketing clearance for Lexiva (fosamprenavir calcium) (Lex-ee'-va, formerly GW433908, or 908), a new protease inhibitor (PI) for the treatment of HIV infection in adults in combination with other antiretroviral medications.

The following points should be considered when initiating therapy with Lexiva/ritonavir (Lexiva/r) in PI-experienced patients: the PI-experienced patient study was not large enough to reach a definitive conclusion that Lexiva/r and lopinavir/ritonavir are clinically equivalent. Once-daily administration of Lexiva plus ritonavir is not recommended for PI-experienced patients. Lexiva was co-discovered by GlaxoSmithKline (GSK) and Vertex Pharmaceuticals Incorporated.

Lexiva, a PI that can be taken once or twice daily without food or water restrictions, has been evaluated in clinical trials with both PI-experienced and antiretroviral therapy (ART)-naive HIV patients.

"The drug's QD and BID dosing options with no food or water restrictions, and a low pill burden demonstrate GSK's ongoing commitment to providing flexible anti-HIV therapies for patients," said Doug Manion, Vice President of Clinical Development and Medical Affairs at GSK.

More than 1,200 people -- both ART-naive and PI-experienced patients -- participated in three Phase III trials to test the safety and efficacy of Lexiva with and without ritonavir. In all three trials, study drugs were taken as part of combination therapy that included two nucleoside reverse transcriptase inhibitors.