GSK's Lexiva OK to use with 100mg ritonavir

UK-based drug major GlaxoSmithKline says that its HIV protease inhibitor Lexiva (fosamprenavir calcium) may now be administered in combination with 100mg of ritonavir, a component of Abbott Laboratories' Kaletra, that helps prevent the enzymatic degradation of protease inhibitors. This effect increases Lexiva's therapeutic half-life, enabling it to more effectively prevent viral replication.

Originally cleared by the US Food and Drug Administration for the treatment of PI-naive HIV patients in 2003 (Marketletters passim), Lexiva is designed to provide a flexible dosing option that does not restrict the individual's consumption of food and water, unlike the majority of protease inhibitors.

The FDA approved the label extension for the combination of once-daily Lexiva 1,400mg with 100mg of ritonavir in adult HIV infected patients who have not previously taken a protease inhibitor. The agency's decision is based on pharmacokinetic data, published in the February issue of the journal Antimicrobial Agents and Chemotherapy, which demonstrated that the combination achieved comparable Lexiva plasma levels to regimens in which it was used in combination with 200mg ritonavir.