1. CI-1 Tarceva ® (erlotinib) Tablets in Combination with Gemcitabine as a 1st-line Treatment of Pancreatic Cancer Presentation to the Oncologic Drugs Advisory Committee OSI Pharmaceuticals, Inc. 13 September 2005

2. CI-2 Introduction Pablo J. Cagnoni, MD Vice President Medical Affairs & Translational Research OSI Pharmaceuticals, Inc.

3. CI-3 Pancreatic Cancer Supplemental NDA sNDA for pancreatic cancer indication was submitted 29 April 2005 – Based on a 569 patient study that showed a statistically significant improvement in overall survival Indication – Tarceva, in combination with gemcitabine, for the 1st-line treatment of patients with unresectable locally advanced, or metastatic pancreatic cancer Dosage – Tarceva: 100 mg PO once daily + gemcitabine (standard approved dose and schedule)

4. CI-4 Tarceva for Patients with Pancreatic Cancer Agenda Introduction Pablo J. Cagnoni, MD Background & PA.3 Study DesignMalcolm Moore, MD Clinical Efficacy Data Review of Study PA.3Gary M. Clark, PhD Clinical Safety Data Review of Study PA.3Karsten Witt, MD Risk/Benefit SummaryMace Rothenberg, MD

5. CI-5 List of External Experts for Q & A J. Randolph Hecht, MD Clinical Professor of Medicine Director, UCLA GI Oncology Program University of California Los Angeles School of Medicine Wendy Parulekar, MD NCIC Clinical Trials Group Queen’s University Malcolm Moore, MD Professor of Medicine and Pharmacology Chair, NCIC Clinical Trials Group GI Committee Princess Margaret Hospital University of Toronto Mace Rothenberg, MD Professor of Medicine and Director, Phase I Drug Development Vanderbilt Ingram Cancer Center

6. CI-6 OSI Pharmaceuticals Team for Q & A Clinical Development – Pablo J. Cagnoni – Janna Christy-Bittel – Jennifer Culbertson – Karsten Witt Biostatistics & Data Management – Gary M. Clark – Bret Wacker Biopharmaceutics/Preclinical – Marta Hamilton – Ken Iwata – Frank Richardson

7. CI-7 Tarceva (erlotinib) Tablets Orally available, small-molecule inhibitor of HER1/EGFR tyrosine kinase Potent, selective EGFR-TK inhibitor (IC 50 = 2 nM) First clinical development candidate from OSI/Pfizer research collaboration in cancer Collaboration with Genentech and Roche since January 2001 N N HN O O HCl O O

8. CI-8 Tarceva Regulatory History Original NDA received full approval by FDA on 18 November 2004 – Indication: monotherapy for the treatment of NSCLC after failure of at least 1 prior chemotherapy – 731-patient study showed a statistically significant improvement in overall survival with Tarceva vs best supportive care >18,000 patients have been treated since approval Over 100 clinical trials are currently ongoing

9. CI-9 Single-Agent Tarceva in NSCLC Study BR.21—Overall Survival †Two-sided log-rank test stratified by ECOG PS, number of prior regimens, prior platinum, best response to prior chemotherapy HR = 0.73 95% CI (0.61, 0.86) p-value < 0.001 †

10. CI-10 Rationale for Targeting HER1/EGFR in Pancreatic Cancer HER1/EGFR overexpression is common Elevated HER1/EGFR and EGF are associated with more aggressive disease and poor patient prognosis In preclinical models, HER1/EGFR inhibitors enhance gemcitabine-induced tumor apoptosis

11. CI-11 Objectives of Presentation To review data supporting the need for new treatment options for patients with pancreatic cancer To present evidence that Tarceva, when added to the current standard of care, gemcitabine, provides the first statistically significant and clinically meaningful increase in survival compared with gemcitabine alone To demonstrate that the combination of Tarceva and gemcitabine offers an effective and tolerable new therapy for the management of pancreatic cancer