Monday, May 14, 2001

OSI Pharmaceuticals, Genentech and Roche Announce Clinical Data From Phase II Ovarian Cancer Trial of Tarceva (OSI-774)

Phase I Mechanism of Action Study Also Presented at American Society of Clinical Oncology Meeting

Uniondale, N.Y., South San Francisco, Calif., and Basel, Switerland -- May 14, 2001 --

OSI Pharmaceuticals, Inc. (Nasdaq: OSIP), Genentech, Inc. (NYSE: DNA) and Roche announced today positive data from a Phase II single agent study with the anti-cancer drug candidate, Tarceva™ (OSI-774) for patients with advanced ovarian cancer. Clinical results were presented at the 37th Annual Meeting of the American Society of Clinical Oncology (ASCO). Detailed updates were also presented on Saturday, May 12th at ASCO demonstrating the potential utility of Tarceva™ as a single agent treatment for patients with non-small cell lung and head and neck cancer (see separate news release). Tarceva™ is a small-molecule oral anti-EGFR (Epidermal Growth Factor Receptor) drug candidate. EGFR is activated in approximately 30 percent of all solid tumors.

Neil Finkler, M.D., a lead investigator and Co-director, Division of Gynecologic Oncology at Walt Disney Memorial Center Institute at Florida Hospital, reported interim data from a Phase II study of 34 patients with advanced refractory ovarian cancer.

Out of the 30 evaluable patients, four partial responses (13 percent) (two unconfirmed) were documented. In addition, 14 patients (46 percent) showed evidence of disease stabilization. Eight of the patients (33 percent) in the study remain alive and 14 patients (46 percent) survived for longer than 300 days. Median survival for all patients in the study was 242 days. As seen in the non-small cell lung and head and neck trials, rash and rash related disorders together with mild diarrhea were the principal side effects with approximately 82 percent of the patients exhibiting rash in the ovarian study.

Qualification criteria for the open label, single agent study required failure of at least one round of platinum-based chemotherapy and to have EGFR-positive tumors. Tarceva™ (150 mg) was given orally as a single agent on a once-a-day dosing schedule. Objective clinical responses were evaluated at eight weeks and classified as either partial responses (>50 percent reduction in tumor size), stable disease, or progressive disease (>25 percent increase in tumor size).

"Tarceva™ has demonstrated promising indications of anti-cancer activity including objective partial responses and evidence of disease stabilization. The duration of survival in this open-label trial compares to that seen with chemotherapy regimens in similar patient populations. Phase II randomized, controlled studies of Tarceva™ are warranted to confirm this encouraging observation," stated Dr. Finkler.

Further studies are in discussion with the U.S. National Cancer Institute's Cancer Therapy Evaluation Program (CTEP) to collaborate with OSI to conduct clinical trials in multiple tumor types including gynecological malignancies, epithelial malignancies of the gastrointestinal and genitourinary tracts, and brain tumors.

Phase I Mechanism of Action Study

Additional studies on Tarceva™ were presented by Manuel Hidalgo, M.D., Ph.D., The University of Texas Health Science Center in San Antonio, Texas. These translational research studies demonstrated a feasible method to quantify the effects of Tarceva™ on EGFR in tumor and normal tissues in clinical trials. Tarceva™ was shown to inhibit activation of the Epidermal Growth Factor Receptor (EGFR) in clinical specimens from head and neck carcinoma patients undergoing treatment with the drug. Immunohistochemical evaluation of EGFR in these tumor specimens indicated that Tarceva™ was able to inhibit EGFR activation/signaling in these patients supporting the putative mechanism of action of the drug.

"We are very encouraged by the data documenting single agent anti-cancer activity in patients with ovarian, non-small cell lung and head and neck carcinomas. The clinical studies on Tarceva™ presented at this year's ASCO meeting support the potential promise of this agent in the treatment of patients with a wide variety of malignancies," stated Colin Goddard, Ph.D., Chairman and Chief Executive Officer of OSI Pharmaceuticals, Inc. "We are continuing to broaden the development program of Tarceva™ with our partners, Genentech and Roche."

OSI Pharmaceuticals is a leading biopharmaceutical company with a substantial portfolio of product opportunities for commercialization with the pharmaceutical industry. OSI's research programs are focused in the areas of cancer therapeutics, respiratory diseases, diabetes, and cosmeceuticals. OSI utilizes a comprehensive drug discovery and development capability to facilitate the rapid and cost-effective discovery and development of novel, small molecule compounds against more than 40 gene targets.

Genentech, Inc. is a leading biotechnology company that discovers, develops, manufactures and markets human pharmaceuticals for significant unmet medical needs. Fourteen of the currently approved biotechnology products stem from Genentech science. Genentech markets nine biotechnology products directly in the United States. The company has headquarters in South San Francisco, California and is traded on the New York Stock Exchange under the symbol DNA.

Headquartered in Basel, Switzerland, Roche is one of the world's leading research-oriented healthcare groups in the fields of pharmaceuticals, diagnostics, and vitamins. Roche's products and services address prevention, diagnosis and treatment of diseases. Roche is a world leader in oncology -- included in its portfolio; Xeloda (breast cancer and colorectal cancer), Herceptin (breast cancer), MabThera (Non-Hodgkin's lymphoma), NeoRecormon (anemia in cancer patients), Roferon-A (leukemia, Kaposi's sarcoma, malignant melanoma), Bondronat (tumour-induced hypercalcemia), Furtulon (malignant tumours, only available in Japan) and the anti-emetic drug Kytril (used in chemotherapy induced emesis). Not all products and indications are available in all countries.

Investors may access a webcast regarding this announcement over the Internet by logging onto: http://www.osip.com or http://www.gene.com or http://www.vcal.com/NASApp/VCall/EventPage?ID=74590 on Monday, March 14th at 3:15PM Eastern time (12:15PM Pacific time). A replay of this call will also be available until May 15th at 6:00PM Eastern time by dialing, 800-633-8284 or 858-812-6440 -- call number: 18780057

Additional information on OSI Pharmaceuticals is available on the World Wide Web at http://www.osip.com

This news release contains forward-looking statements. These statements are subject to known and unknown risks and uncertainties that may cause actual future experience and results to differ materially from the statements made. Factors that might cause such a difference include, among others, uncertainties related to the identification of lead compounds, the successful pre-clinical development thereof, the completion of clinical trials, the FDA review process and other governmental regulation, pharmaceutical collaborators' ability to successfully develop and commercialize drug candidates, competition from other pharmaceutical companies, product pricing and third part reimbursement, and other factors described in OSI Pharmaceuticals' filings with the Securities and Exchange Commission.

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