Amprenavir (Vertex Pharmaceuticals Inc)

Amprenavir is an oral, non-peptidic HIV-protease inhibitor undergoing phase III trials for the treatment of HIV and AIDS. In October 1998, Glaxo Wellcome submitted a new drug application (NDA) for amprenavir (Agenerase) in the US and Canada for which there is an April 1999 review deadline and in November 1998, filed an application for market approval in Europe. This product has been designated for fast-track approval. Merrill Lynch anticipates product launch in mid-1999 and estimates that Agenerase will reach peak sales of $500M after its launch. Amprenavir is a small molecule with significant aqueous solubility designed to combine antiviral potency with good oral bioavailability. The compound is a potent and specific inhibitor of isolated HIV-1 protease and of HIV-1 replication in T-cells and shows good absorption after oral dosage in man. The plasma half-life of amprenavir is approximately 10 h, allowing for twice daily dosing. The drug appears to cross the blood-brain barrier which may be an important feature in long-term treatment. Amprenavir selects for a unique mutation in the HIV-1 protease gene in vitro, and shows no or limited cross-resistance to other protease inhibitors. In January 1999 Paribas predicted Glaxo sales of pound sterling 75 million in 1999 rising to pound sterling 400 million in 2003.