By Lisa Seachrist

Washington Editor

Vertex Pharmaceuticals Inc. said its partner, Glaxo Wellcome plc, launched a pivotal Phase III trial of Vertex's second-generation protease inhibitor, identified as VX-478, for treatment of HIV.

"This is the first pivotal trial of VX-478," said Lynne H. Brum, senior director of corporate communications for Vertex, of Cambridge, Mass. "It is a milestone in the development program."

London-based Glaxo is in a royalty agreement with Vertex to develop the protease inhibitor for the U.S. and European markets.

The trial will test the drug in combination with Glaxo's AZT and 3TC against a dual combination of AZT and 3TC. Glaxo is enrolling 240 HIV-positive adults who have more than 200 CD4 cells per milliliter of blood and HIV RNA counts greater than 10,000 copies per milliliter. In addition, all patients must have no prior use of antiretroviral drugs.

The trial will be conducted at approximately 30 clinical sites in the U.S., Canada and Europe and is expected to last for 48 weeks to test the durability of the effect. Brum said Glaxo intends to file for accelerated approval should the drug show significant antiretroviral activity as measured by a decrease in the number of copies of HIV RNA found in the blood. Glaxo intends to launch the drug in mid-1998.

In addition, Glaxo will begin a pediatric Phase III trial of VX-478 as an adjunct to standard therapy within the next few weeks. Glaxo also has the drug in Phase II studies in combination with protease inhibitors produced by Merck & Co., of Whitehouse Station, N.J., Roche Holding Ltd., of Basel, Switzerland, and Agouron Pharmaceuticals Inc., of La Jolla, Calif.

Vertex's drug currently is being evaluated as a single therapy in an AIDS Clinical Trials Group Phase II study.

Brum noted Vertex's Far East partner, Kissei Pharmaceutical Co. Ltd., of Matsumoto, Japan, is expected to initiate clinical trials of VX-478 later this year.

Vertex's stock (NASDAQ:VRTX) closed Wednesday at $49.25, up $0.50. *