Public Release: 

Vertex Pharmaceuticals Report Encouraging Preliminary Data From Phase II Clinical Study With HIV Protease Inhibitor 141W94

Vertex Pharmaceuticals

Cambridge, MA, October 13, 1997 -- Vertex Pharmaceuticals Incorporated (NASDAQ: VRTX) today announced for the first time preliminary 12 week data from an ongoing Phase II study of 141W94 (VX-478), an HIV protease inhibitor currently in Phase III clinical trials. The data, presented at the 6th European Conference on Clinical Aspects and Treatment of HIV-infection in Hamburg, Germany, showed that 141W94 in combination with RetrovirR (AZT) and EpivirR (3TC) was generally well-tolerated and produced potent antiviral activity. In the triple combination study (141W94, AZT, 3TC), approximately 70% of patients had undetectable viral load at 12 weeks.

"This study is the first of a series of data to be presented on 141W94, and support the favorable tolerability and antiviral profile of the compound," commented Dr. Vicki L. Sato, Senior Vice President of Research and Development and Chief Scientific Officer of Vertex. "Additional 141W94 data from a number of treatment regimens is expected in the coming months."

"In the context of current therapy, the Phase II triple combination study shows that 141W94 displayed potent antiviral activity at all three doses tested in combination with AZT and 3TC," commented Mike Rogers, Ph.D., Assistant Director, Antiviral Clinical Research at Glaxo Wellcome. "This study is part of an extensive international clinical program to evaluate 141W94 in a variety of drug regimens and patient populations for the management of HIV infection."

At the conference, Dr. Stephane de Wit of Saint-Pierre University Hospital in Brussels, Belgium, reported results from the "Vanguard" study, a pilot efficacy trial of three doses (900 mg, 1050 mg and 1200 mg, twice daily) of 141W94 in combination with RetrovirR (AZT) and EpivirR (3TC). At 12 weeks, patients taking 141W94 at the highest dose, 1200mg twice daily, plus RetrovirR (AZT) and EpivirR (3TC) had a median 2.65 log reduction in viral load (greater than 99.8%) from baseline as compared to a 1.33 log reduction for the control arm, RetrovirR and EpivirR. At 12 weeks, approximately 70 percent of patients across all 141W94 dose groups experienced drops in HIV viral load to below the limits of detection (400 copies HIV RNA/ml) for the assay used. The combination was generally well-tolerated with diarrhea, headache, nausea and rash being the most commonly reported adverse events for patients treated with these three drugs.

Since early 1997, Glaxo Wellcome has been conducting extensive pivotal Phase III clinical trials of 141W94. Three pivotal Phase III clinical trials are ongoing to assess the tolerability and antiviral activity of 141W94 in combination therapy in HIV-positive adults and children. The Phase III clinical trial initiated earlier this year in adults is fully enrolled and a third Phase III clinical trial begun last month comparing 141W94 with indinavir is expected to enroll patients rapidly. Data generated from 16 weeks of treatment in these studies is intended to support filing of market approval of 141W94. To date approximately 500 patients have participated in 141W94 clinical studies. More than 125 clinical trial sites in the United States, Canada, Europe and Australia and more than 1000 patients are expected to participate in the ongoing Phase II and pivotal Phase III clinical evaluation of 141W94.

141W94, a second generation HIV protease inhibitor, was designed at Vertex Pharmaceuticals and is being developed by Glaxo Wellcome worldwide, outside of the Far East, and Kissei Pharmaceutical Co., Ltd. (Matsumoto-City, Japan) in the Far East.

Glaxo Wellcome is a world leader in developing therapies for the treatment of HIV and AIDS. RetrovirR was the first antiviral medicine developed for use in adults and children with HIV infection. Retrovir was introduced in 1987 and is now available in over 100 countries. EpivirR has been cleared for use in over 25 countries including the US and the European Union. Epivir has also been approved as 3TC in Canada, Australia, South Africa, Switzerland, Uruguay, New Zealand, Mexico, Colombia and Argentina. In addition, Glaxo Wellcome discovered, developed and markets several products for the treatment of HIV-related opportunistic infections.

Vertex Pharmaceuticals Incorporated is engaged in the discovery, development and commercialization of novel, small molecule pharmaceuticals for the treatment of diseases for which there are currently limited or no effective treatments. The Company is a leader in the use of structure-based drug design, an approach to drug discovery that integrates advanced biology, biophysics and chemistry. The Company is concentrating on the discovery and development of drugs for the treatment of viral diseases, multidrug resistance in cancer, autoimmune diseases, inflammatory diseases, and neurodegenerative diseases.

Epivir and 3TC (lamivudine) and Retrovir and AZT (zidovudine) are trademarks of the Glaxo Wellcome Group of Companies.

Additional Glaxo contact: Doug Stokke, Manager, Product Communications (919) 483-2311

Additional Vertex contact: Justine Schultz, Corporate Communications Specialist, (617) 577-6000

Vertex's press releases are also available by fax-on-demand at (800) 758-5804 -- Code: 938395

There can be no assurance that the planned clinical trials will continue, that initial clinical trial results will be predictive of any future results, that drugs under development by the Company or any of its partners will receive marketing approval from the U.S. Food and Drug Administration or other authorities, or that drugs, if any, which receive such approval will be marketed successfully. Investors are also directed to consider other risks and uncertainties discussed in documents filed by the company with the Securities and Exchange Commission.

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