Gilead Initiates Phase II Study of NX 211 in Patients With Recurrent Small Cell Lung Cancer.

Business Editors/Health & Medical Writers

FOSTER CITY, Calif.--(BW HealthWire)--Dec. 21, 2000

Gilead Sciences, Inc. (Nasdaq:GILD) announced today that it has initiated a Phase II trial of NX 211 in patients with recurrent small cell lung cancer. This trial is designed to evaluate the anti-tumor efficacy and safety of NX 211 in up to 87 patients at numerous sites in the United States. NX 211 is a liposomal formulation of a novel topoisomerase I inhibitor being developed for the potential treatment of various solid tumor cancers.

In early November, Gilead initiated Phase II clinical trials of NX 211 with two separate studies in ovarian cancer patients. The first study is in patients who have failed prior therapy and the second trial includes patients who are resistant to topotecan.

"In just over one year, our oncology team has accelerated the development of NX 211 from an Investigational New Drug to a compound in Phase II clinical trials for multiple solid tumor types," said John C. Martin, Ph.D., President and Chief Executive Officer, Gilead Sciences. "This achievement with our liposomal technology is the result of the collective efforts of the many talented individuals in our research and development groups, whose ongoing work will help further develop Gilead's growing portfolio of new agents for the treatment of cancer."

Study Design

This Phase II trial (Study 110-08) is an open-label, multi-center study that will evaluate the efficacy and safety of NX 211 as determined by response rate, time to disease progression, survival and patient tolerance. The study will enroll patients who have relapsed during or following administration of first-line therapy. Patients will be treated with NX 211 on days 1 and 8, repeated every 21 days.

Phase I Results

Phase I data were presented in early November describing the safety and the pharmacokinetic profile of NX 211 at both the Chemotherapy Foundation Symposium XVIII in New York and the 11th NCI-EORTC-AACR Symposium on New Drugs in Cancer Therapy in Amsterdam, The Netherlands. Gilead initiated Phase II trials based on the results from three Phase I trials, which evaluated different doses and schedules of NX 211 in 87 patients with a variety of advanced malignancies. A maximum tolerated dose was determined for each schedule of NX 211, with myelosuppression as the primary dose-limiting toxicity. Although these Phase I studies were not designed to evaluate efficacy, there was indication of clinical and biological anti-tumor activity in seven patients.

"Although most patients with small cell lung cancer respond to initial therapy, the majority relapse rapidly," said Nicole Onetto, M.D., Senior Vice President, Medical Affairs, Gilead Sciences. "There remains a significant need for new treatments for this patient population. We believe recurrent small cell lung cancer may be an important target indication for NX 211."

NX 211

NX 211 is a liposomal formulation of the anti-cancer agent lurtotecan. Gilead licensed worldwide rights to lurtotecan from Glaxo Wellcome (NYSE:GLX) in 1998. Lurtotecan functions by inhibiting topoisomerase I, an enzyme in the cell nucleus involved in the unwinding of DNA segments. By inhibiting topoisomerase I, NX 211 will prevent DNA from unwinding, thereby preventing cell replication.

Small Cell Lung Cancer

Lung cancer is the leading cause of cancer death among both men and women. According to the American Cancer Society statistics, approximately 164,000 new lung cancer cases will be diagnosed in 2000. Small cell lung cancer accounts for approximately 20 percent of all diagnosed lung cancers. It is predominately found in people who have a history of smoking. There are two stages of small cell lung cancer: limited and extensive disease. The standard of care for people with small cell lung cancer includes chemotherapy and/or radiation therapy. Recurrence after initial therapy is very common and represents a significant medical challenge to physicians treating these patients.

Patients and physicians who would like more information about enrollment in this study may contact Gilead Sciences Medical Information at 1-800-GILEAD-5 (1-800-445-3235) or 650/574-3000 from outside the United States.

The Gilead Oncology Portfolio

In addition to infectious diseases, oncology is a key area of therapeutic focus at Gilead Sciences. The company is committed to building its portfolio of anti-cancer compounds by accelerating the development of programs currently in the clinic, using its proprietary liposomal drug delivery technology to improve the therapeutic index of investigational agents, supporting research efforts aimed at new molecular targets and seeking opportunities to in-license promising compounds.

Gilead's most advanced product candidate in oncology, NX 211, is a proprietary liposomal formulation of the anti-cancer agent lurtotecan and is currently in Phase II clinical trials. Recently, Gilead announced the licensing of a thymidylate synthase inhibitor, which will be reformulated as the liposomal product GS 7904L. Targeted for the potential treatment of various solid tumor cancers, GS 7904L is expected to enter Phase I clinical trials in 2001. Additionally, Gilead has in-licensed GS 7836, a nucleoside analogue for the potential treatment of cancer, and plans to begin preclinical testing of this compound during 2001 with the goal of initiating Phase I clinical trials in early 2002. Gilead is also pursuing several discovery programs aimed at developing novel cancer therapies.

Gilead Sciences

Gilead Sciences, Inc., headquartered in Foster City, Calif., is an independent biopharmaceutical company that seeks to provide accelerated solutions for patients and the people who care for them. Gilead discovers, develops, manufactures and commercializes proprietary therapeutics for challenging infectious diseases (viral, fungal and bacterial infections) and cancer. Gilead maintains research, development or manufacturing facilities in Foster City, Calif.; Boulder, Colo.; San Dimas, Calif.; Cambridge, U.K. and Dublin, Ireland and sales and marketing organizations in the United States, Europe and Australia.

This press release includes forward-looking statements, within the meaning of the Private Securities Litigation Reform Act of 1995, including statements relating to the safety profile of NX 211 and the anti-tumor activity observed in Phase I studies. These statements are subject to risks, uncertainties and other factors that could cause actual results to differ materially from those referred to in the forward-looking statements. Such risks and uncertainties include: the risk that the safety data observed in Gilead's Phase I trials may not be observed in its more reliable Phase II trials; uncertainties associated with observations of anti-tumor activity in Phase I trials that were not designed to evaluate efficacy, and the risk that this activity may not be observed in Phase II trials that are designed to evaluate efficacy; the risk that Phase II trials may demonstrate that NX 211 does not have sufficient anti-tumor activity at tolerable doses; the risk that GS 7904L and GS 7836 may not be suitable for clinical development as early as we anticipate or at all; and other risks related to clinical trials and regulatory approvals. The reader is cautioned not to rely on these forward-looking statements. These and other risks are described in detail in the Gilead Annual Report on Form 10-K for the year ended Dec. 31, 1999 and in Gilead's Quarterly Reports on Form 10-Q, all of which are on file with the U.S. Securities and Exchange Commission.

For more information on Gilead Sciences, please visit the company's Web site at www.gilead.com or call the Gilead Corporate Communications Department at 1-800-GILEAD-5 (1-800-445-3235).