Description ABT-263 is a small molecule that is designed to restore apoptosis, also known as programmed cell death, by blocking the function of pro-survival Bcl-2 family proteins. Apoptosis is a natural process by which damaged or unwanted cells, including those that are cancerous, die and are cleared from the body. The Bcl-2 family proteins, which are expressed at high levels in many tumors, play a central role in regulating apoptosis and, consequently, are thought to impact tumor formation, tumor growth and resistance to treatment.

Development Status Phase I clinical trials for solid tumors and hematologic malignancies are ongoing evaluating ABT-263 in combination with various chemotherapy regimens and in combination with targeted medicines, such as Rituxan® (Rituximab) and Tarceva® (erlotinib). Phase I/II clinical trials evaluating ABT-263 as a single agent for relapsed or refractory chronic lymphocytic leukemia, relapsed or refractory lymphoid malignancies, and advanced small cell lung cancer are ongoing. A Phase II clinical trial for front-line chronic lymphocytic leukemia in combination with Rituxan is planned.

This molecule is being developed in collaboration with Abbott.

For Rituxan full prescribing information, including Boxed WARNINGS, Medication Guide and additional important safety information, please visit http://www.rituxan.com or call 1-800-821-8590.

For Tarceva full prescribing information, including additional important safety information, please visit http://www.tarceva.com or call 1-877-TARCEVA.

Additional Information on Clinical Trials For inquiries about our clinical trials, please submit a request through our information request form or call (888) 662-6728.

National Institutes of Health Website: www.clinicaltrials.gov

February 2010