A report in Nature shows that four patients treated with a Merck inhibitor of the HIV protease enzyme developed resistance to the drug, and to several other protease inhibitors as well. But despite the report, which has been anticipated for several weeks (see BioCentury, March 13), no one is tossing in the towel on these drugs. "We think protease inhibitors represent a very promising treatment for AIDS," said Vertex Pharmaceuticals Inc. spokesperson Lynne Brum.

"We believe the Merck compound was not dosed optimally, given its pharmacokinetics