8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

Current Report Pursuant to Section 13 or 15(d) of
The Securities Exchange Act of 1934

June 2, 2005
Date of Report (Date of earliest event reported)

OSI PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

Delaware	0-15190	13-3159796
(State or other jurisdiction of incorporation)	(Commission File Number)	(I.R.S. Employer Identification No.)

58 South Service Road
Melville, NY 11747
(Address of principal executive offices)

(631) 962-2000
(Registrant’s telephone number, including area code)

N/A
(Former name or former address,
if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a- 12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

TABLE OF CONTENTS

	ITEM 8.01 Other Events
	ITEM 9.01 EXHIBITS
SIGNATURE
EXHIBIT INDEX
EX-99.1: PRESS RELEASE
EX-99.2: PRESS RELEASE

ITEM 8.01 Other Events

     On June 2, 2005, OSI Pharmaceuticals, Inc. (“OSI”) announced the issuance of U.S. Patent No. 6,900,221 for Tarceva® (erlotinib) with respect to a crystalline polymorph of Tarceva, methods for treating various cancers and processes for production of the crystalline polymorph. Details regarding the patent are set forth in OSI’s press release dated June 2, 2005 which is attached as Exhibit 99.1 to this Current Report on Form 8-K and incorporated herein by reference.

     On June 13, 2005, OSI provided a summary of data presented during the American Diabetes Association’s 65^th Annual Scientific Meeting held from June 10^th to June 14^th in San Diego, California. Details regarding the summary are set forth in OSI’s press release dated June 13, 2005 which is attached as Exhibit 99.2 to this Current Report on Form 8-K and incorporated herein by reference.

ITEM 9.01 EXHIBITS

Exhibit No.	Description
99.1	Press release, dated June 2, 2005.
99.2	Press release, dated June 13, 2005.

SIGNATURE

     Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date: 6/17/05	OSI PHARMACEUTICALS, INC.
	By:	/s/ Michael G. Atieh
		Name:	Michael G. Atieh
		Title:	Executive Vice President and Chief Financial Officer

EXHIBIT INDEX

Exhibit No.	Description
99.1	Press release, dated June 2, 2005.
99.2	Press release, dated June 13, 2005.

EX-99.1

EXHIBIT 99.1

NEWS RELEASE

OSI Pharmaceuticals Contact:
Kathy Galante (631)-962-2000

OSI Pharmaceuticals Announces Issuance of Additional U.S. Patent for Tarceva; Extends Patent Exclusivity

     MELVILLE, N.Y., Jun 02, 2005 (BUSINESS WIRE) — OSI Pharmaceuticals, Inc. (NASDAQ: OSIP) today announced the issuance of U.S. Patent No. 6,900,221 by the United States Patent and Trademark Office. The patent is directed to a crystalline polymorph of Tarceva™ (erlotinib), methods for treating various cancers, and processes for production of the crystalline polymorph. The claims in the patent will extend exclusive protection of Tarceva until 2020.

     “The issuance of the polymorph patent extends our current intellectual property protection for Tarceva by approximately five years,” stated Colin Goddard, Ph.D., Chief Executive Officer of the Company. “With a strong launch underway and solid data from this year’s ASCO meeting supporting the evolution of the brand to earlier-stage lung cancer patients; different disease settings; and use in combination regimens with other targeted therapies we continue to believe that Tarceva has a bright future in treating cancer patients.”

     In the U.S., Tarceva is also protected by U.S. Patent No. 5,747,498, which was issued in 1998, covering composition of matter, processes for its preparation, methods of treating cancer, and pharmaceutical compositions containing Tarceva. Additional patents for Tarceva are also issued in areas outside the U.S., including Europe and Japan.

     About Tarceva

     Tarceva is a small molecule designed to target the human epidermal growth factor receptor 1 (HER1) pathway, which is one of the factors critical to cell growth in non-small cell lung cancer (NSCLC) and other solid tumors. HER1, also known as EGFR, is a component of the HER signaling pathway, which plays a role in the formation and growth of numerous cancers. Tarceva is designed to inhibit the tyrosine kinase activity of the HER1 signaling pathway inside the cell, which may block tumor cell growth. Tarceva is the only HER1/EGFR-targeted therapy proven to significantly prolong survival in second-line NSCLC as a single agent.

     Tarceva was approved by the FDA in November 2004 and is an oral tablet indicated for daily administration for the treatment of patients with locally advanced or metastatic NSCLC after failure of at least one prior chemotherapy regimen. Results from two earlier large, randomized, placebo-controlled clinical trials in first-line advanced NSCLC patients showed no

clinical benefit with concurrent administration of Tarceva with doublet platinum-based chemotherapy (carboplatin and paclitaxel or gemcitabine and cisplatin) and its use is not recommended in that setting.

     Additional early-stage trials of Tarceva are being conducted in other solid tumors. In April 2005, OSI submitted a supplemental New Drug Application (sNDA) with the FDA for use of Tarceva plus gemcitabine chemotherapy for the treatment of advanced pancreatic cancer in patients who have not received any previous treatment. Tarceva is the only EGFR therapy proven to significantly prolong survival in first-line locally advanced or metastatic pancreatic cancer in combination with gemcitabine.

     Tarceva Safety Profile

     In the pivotal NSCLC trial, the most common adverse reactions in patients receiving Tarceva were rash and diarrhea. Grade 3/4 rash and diarrhea occurred in 9 and 6 percent of Tarceva-treated patients, respectively. Rash and diarrhea each resulted in discontinuation of 1 percent of Tarceva-treated patients. Dose reduction for rash and diarrhea was needed for 6 and 1 percent of patients, respectively. Historically, there have been infrequent reports of serious interstitial lung disease (ILD), including fatalities, in patients receiving Tarceva for treatment of NSCLC or other advanced solid tumors. In the pivotal trial in NSCLC, severe pulmonary reactions, including potential cases of interstitial lung disease, were infrequent (0.8 percent) and were equally distributed between treatment arms. The overall incidence of ILD in Tarceva-treated patients from all NSCLC studies was approximately 0.7 percent.

     About OSI Pharmaceuticals

     OSI Pharmaceuticals is committed to shaping medicines and changing patients’ lives by discovering, developing and commercializing high-quality and novel pharmaceutical products that extend life or improve the quality of life for cancer and diabetes patients worldwide. The company operates through two business teams, (OSI) Oncology and (OSI) Prosidion. (OSI) Oncology is focused on developing molecular targeted therapies designed to change the paradigm of cancer care. (OSI) Prosidion is committed to the generation of novel, targeted therapies for the treatment of type II diabetes and obesity. OSI’s flagship product, Tarceva™ (erlotinib), is the first drug discovered and developed by OSI to obtain FDA approval and the only EGFR inhibitor to have demonstrated the ability to improve survival in both non-small cell lung cancer and pancreatic cancer patients. OSI markets Tarceva™ through partnerships with Genentech Inc. in the U.S. and with Roche throughout the rest of the world.

     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, the completion of clinical trials, the FDA review process and other governmental regulation, OSI’s and its collaborators’ abilities to successfully develop and commercialize drug candidates, competition from other pharmaceutical companies, the ability to effectively market products, and other factors described in OSI Pharmaceuticals’ filings with the Securities and Exchange Commission.

EX-99.2

EXHIBIT 99.2

NEWS RELEASE

OSI Pharmaceuticals Contact:
Kathy Galante (631)-962-2000

OSI Pharmaceuticals Summarizes Research Data Presented at the American Diabetes Association’s 65th Annual Scientific Meeting

     MELVILLE, N.Y.—(BUSINESS WIRE)—June 13, 2005—OSI Pharmaceuticals, Inc. (NASDAQ: OSIP) today provided a summary of data presented during the American Diabetes Association’s 65th Annual Scientific Meeting held from June 10th — 14th in San Diego, Calif. Presentations were made on the Company’s diabetes drug candidates PSN105 and PSN010, both of which are glucokinase activators (GKAs). PSN105 and PSN010 modulate the activity of Glucokinase (GK), an enzyme which plays a key role as the body’s glucose sensor in the liver and pancreas. Data were also presented on PSN357, a glycogen phosphorylase inhibitor (GPI), which is designed to rapidly lower blood glucose levels by preventing glycogen breakdown to glucose in the liver. Discovered by (OSI) Prosidion, OSI’s diabetes and obesity team, these small molecule drug candidates are scheduled to enter clinical trials in 2005.

     Anti-hyperglycemic Effects of Novel Long- and Short-Acting Glucokinase Activators (PSN105 and PSN010) in Diabetic Animals — Matthew C.T. Fyfe, et al (Presentation Number: 522-P)

     GKAs may represent a new approach to diabetes therapy as these compounds attenuate hyperglycemia by increasing both hepatic glucose metabolism and glucose-stimulated pancreatic insulin release. Pre-clinical data showed that PSN105 and PSN010 activate glucokinase (GK) strongly in vitro and in vivo. PSN105 was cleared more slowly than PSN010, leading to the premise that these GKAs could have markedly different durations of action. The respective long- and short-acting anti-hyperglycemic capabilities of PSN105 and PSN010 were confirmed in several diabetic rodent models. Maximal glucose concentrations were significantly and similarly attenuated by both agents, and prolonged hyperglycemia was alleviated by PSN105. In a subchronic study with PSN105, there were no significant changes in body weight, liver weight, or plasma alanine aminotransferase, free fatty acid or triglyceride concentrations. The distinct PK profiles of the novel anti-diabetic GKAs PSN105 and PSN010 may offer alternative strategies for controlling hyperglycemia in diabetic patients through once-daily or meal-related dosing regimens.

     PSN357, a Novel Glycogen Phosphorylase Inhibitor with Anti-Hyperglycemic Efficacy in Rodent Models of Diabetes — Gerard Thomas, et al (Presentation Number: 567-P)

     The inappropriate over-production of glucose by the liver as a result of glycogen breakdown is a contributor to hyperglycemia in type 2 diabetes. As the rate of glycogenolysis is

regulated by glycogen phosphorylase (GP), inhibition of this key enzyme may constitute a therapeutic option for the treatment of type 2 diabetes. Pre-clinical data presented showed that PSN357 inhibits GP and reduces blood glucose levels in animal models of diabetes following acute and chronic dosing. An increase in liver glycogen was also seen in the study, however heart and skeletal muscle glycogen showed no changes from controls. In addition, a 9-day study in diabetic mice showed that once-daily oral administration of PSN357 maintained anti-hyperglycemic efficacy throughout the period. Other endpoints observed in the study were a 57% increase in liver glycogen and no changes in muscle glycogen or in levels of plasma insulin or alanine aminotransferase. PSN357 is a candidate for clinical development due to its sustained effects in rodent models of diabetes and may represent a novel therapeutic option for treatment of diabetic hyperglycemia.

     “We continue to be encouraged by the results emerging from our diabetes program and look forward to advancing these agents into Phase I clinical trials,” stated Anker Lundemose, M.D., Ph.D., President of (OSI) Prosidion. “In addition, we expect data from our leading diabetes drug candidate, PSN9301, a dipeptidyl peptidase-IV inhibitor, which is currently being evaluated in a Phase II proof-of-concept and dose-ranging study, by the end of 2005.”

     About OSI Pharmaceuticals

     OSI Pharmaceuticals is committed to shaping medicines and changing patients’ lives by discovering, developing and commercializing high-quality and novel pharmaceutical products that extend life or improve the quality of life for cancer and diabetes patients worldwide. The company operates through two business teams, (OSI) Oncology and (OSI) Prosidion. (OSI) Oncology is focused on developing molecular targeted therapies designed to change the paradigm of cancer care. (OSI) Prosidion is committed to the generation of novel, targeted therapies for the treatment of type II diabetes and obesity. OSI’s flagship product, Tarceva™ (erlotinib), is the first drug discovered and developed by OSI to obtain FDA approval and the only EGFR inhibitor to have demonstrated the ability to improve survival in both non-small cell lung cancer and pancreatic cancer patients. OSI markets Tarceva™ through partnerships with Genentech Inc. in the U.S. and with Roche throughout the rest of the world.

     (OSI) Prosidion is the diabetes and obesity business team within OSI Pharmaceuticals dedicated to the discovery and development of novel drugs for the treatment of type 2 diabetes and obesity. (OSI) Prosidion’s lead compound, PSN9301, is a Dipeptidyl Peptidase IV (DPIV) inhibitor currently in Phase II clinical trials. Other products targeting glycogen phosphorylase inhibition and glucokinase activation are scheduled to enter Phase I clinical trials in 2005. (OSI) Prosidion owns or has licensing rights to a portfolio of DPIV medical use patents with claims covering DPIV as a target for anti-diabetes therapy and the use of combinations of DPIV inhibitors with other anti-diabetes drugs such as metformin. A number of non-exclusive licenses to the patent estate have been granted to major pharmaceutical companies. (OSI) Prosidion operates through OSI’s wholly-owned subsidiary, Prosidion Limited, in Oxford, UK.

     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, the completion of clinical trials, the FDA review process and other governmental regulation, OSI’s and its collaborators’ abilities to successfully develop and commercialize drug candidates, competition from other pharmaceutical companies, the ability to effectively market products, and other factors described in OSI Pharmaceuticals’ filings with the Securities and Exchange Commission.