Of the four HIV protease inhibitors on the market, many have shortcomings in key areas of convenience, pharmacokinetics or tolerability. Vertex Pharmaceuticals Inc. and Abbott Laboratories believe that their second generation inhibitors, Agenerase amprenavir and ABT-378, have characteristics that will make their compounds the protease inhibitors of choice in future HIV cocktail regimens.

VRTX Chairman, President and CEO Joshua Boger noted that the two market leaders - Viracept nelfinavir from Agouron Pharmaceuticals Inc. (AGPH, La Jolla, Calif.) and Crixivan indinavir from Merck & Co. Inc. (West Point, Penn.) - must be taken three times a day. "The other key drugs in HIV cocktails are taken two times