FDA grants approval to fosamprenavir calcium
The FDA in October approved fosamprenavir calcium (Lexiva), which is manufactured by GlaxoSmithKline of Research Triangle Park, NC, and Vertex Pharmaceuticals Inc. of Cambridge, MA.
It is a prodrug of amprenavir, a protease inhibitor used to treat infection with HIV-1 by rapidly converting to amprenavir by cellular or serum phosphatases in the body.
Fosamprenavir calcium is indicated in combination with other antiretroviral agents for the treatment of HIV infection in adults. The approval was based on two studies in antiretroviral-naive patients and one study in protease inhibitor-experienced patients.
The FDA says these points should be considered when initiating therapy with Lexiva/ritonavir in protease inhibitor-experienced patients.
- The protease inhibitor-experienced patient study was not large enough to reach a definitive conclusion that Lexiva/ritonavir and lopinavir/ritonavir are clinically equivalent.
- Once-daily administration of fosamprenavir calcium plus ritonavir is not recommended for protease inhibitor-experienced patients.
The most common treatment-emergent adverse events in clinical studies of the drug were diarrhea, nausea, vomiting, headache, and rash and were generally mild to moderate in severity.
Treatment discontinuation due to adverse events occurred in 6.4% of patients receiving the medication and in 5.9% of patients receiving comparator treatments.
Tablets are available for oral administration in a strength of 700 mg fosamprenavir as fosamprenavir calcium (equivalent to approximately 600 mg amprenavir).
Tablets may be taken with or without food. The recommended oral dose of Lexiva, alone or in combination with ritonavir, is as follows:
Therapy-Naive Patients:
- Lexiva 1,400 mg twice daily (without ritonavir).
- Lexiva 1,400 mg once daily plus ritonavir 200 mg once daily.
- Lexiva 700 mg twice daily plus ritonavir 100 mg twice daily.
The twice-daily plus ritonavir dose is supported by pharmacokinetic and safety data.
Protease Inhibitor-Experienced Patients:
- Lexiva 700 mg twice daily plus ritonavir 100 mg twice daily.
Once-daily administration of Lexiva plus ritonavir is not recommended in protease inhibitor-experienced patients. Ritonavir is used to increase the plasma concentration of Lexiva.
The FDA in October approved fosamprenavir calcium (Lexiva), which is manufactured by GlaxoSmithKline of Research Triangle Park, NC, and Vertex Pharmaceuticals Inc. of Cambridge, MA.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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