( Results from Non-clinical Studies Confi...)Sunesis Presents Data Supporting SNS-032's Potential Anticancer,Activity in Multiple Myeloma at the American Association for Cancer,Research Meeting,Health

SOUTH SAN FRANCISCO, April 16, 2007 /PRNewswire-FirstCall/ -- Sunesis Pharmaceuticals, Inc. presented non-clinical data demonstrating SNS-032's apoptotic activity in a multiple myeloma model. These data were presented today in a poster session during the Annual Meeting of the American Association for Cancer Research (AACR).

SNS-032, a selective and potent inhibitor of cyclin-dependent kinases (CDKs) 2, 7 and 9, is currently in a Phase 1 clinical trial for B-cell malignancies, including chronic lymphocytic leukemia, multiple myeloma and mantle cell lymphoma. Non-clinical studies were conducted by Sunesis evaluating SNS-032's mechanism of action and in vitro activity against human multiple myeloma cell line RPMI-8226. Acting through inhibition of CDKs 2, 7, and 9, SNS-032 blocks both the cell cycle and transcription to drive apoptosis, or programmed cell death, in multiple myeloma cells upon exposure for six hours. Researchers also noted that exposure to SNS-032 induced down regulation of key anti-apoptotic factors, cell survival proteins, and growth factors that drive the disease. These results confirm that inhibiting CDKs 2, 7 and 9 targets both unregulated cell proliferation and the microenvironment associated with multiple myeloma and support the dosing regimen currently in use in the company's Phase 1 B-cell malignancy clinical trial.

"Data presented today from our non-clinical study of SNS-032 in multiple myeloma cell lines support our hypothesis that targeted inhibition of CDKs 2, 7 and 9 triggers cell death in hematologic cancer," said Daniel C. Adelman, M.D., Senior Vice President, Research and Development. "In addition, these results provide a pharmacologic basis for the dosing regimen being used in our Phase 1 clinical study, and identify potential biomarkers for monitoring activity."

Data
'"/>