Fosamprenavir: drug development for adherence.

OBJECTIVE: To review the pharmacology, pharmacokinetics, virology, safety, efficacy, and clinical use of fosamprenavir.

DATA SOURCES: A MEDLINE (1966-July 2005) search was conducted using fosamprenavir, Lexiva, amprenavir, and GW433908 as key words. Abstracts from infectious diseases and HIV scientific meetings were identified. Bibliographies of cited articles were reviewed.

STUDY SELECTION AND DATA EXTRACTION: All publications, meeting abstracts, and unpublished information were reviewed and relevant items included. Information from in vitro, preclinical, and Phase II and III clinical trials was included.

DATA SYNTHESIS: Fosamprenavir is a protease inhibitor (PI) prodrug used for the treatment of HIV-1 infection. The active moiety, amprenavir, is extensively metabolized by CYP3A4. In clinical trials, fosamprenavir was at least as effective as amprenavir, with a reduced pill burden. Fosamprenavir was developed with the intention of reducing the pill burden associated with amprenavir. It has demonstrated comparable safety and efficacy with comparator PIs and is associated with limited cross-resistance to other PIs.

CONCLUSIONS: Fosamprenavir is a promising antiretroviral agent with favorable efficacy and tolerability. At this time, data indicate the utility of fosamprenavir in treatment-naïve and PI-experienced HIV-infected patients.