Sunesis Pharmaceuticals Presents Nonclinical Data on SNS-595 at the Annual Meeting of the American Association for Cance...( Nonclinical Studies Demonstrate that...),Health

Nonclinical Studies Demonstrate that SNS-595 Acts through a Dual Mechanism

and May Evade Common Drug Resistance Mechanisms

Research Supports Current Clinical Development of SNS-595 in AML and

Ovarian Cancer and Potential in Additional Indications

SOUTH SAN FRANCISCO, Calif., April 14 /PRNewswire-FirstCall/ -- Sunesis Pharmaceuticals, Inc. (Nasdaq: SNSS) today presented nonclinical data on SNS-595's unique mechanism of action and its anticancer activity at the Annual Meeting of the American Association for Cancer Research (AACR) in San Diego, CA. A Phase 2 single agent clinical trial of SNS-595 in ovarian cancer and a Phase 1b clinical trial of SNS-595 in combination with cytarabine in relapsed/refractory acute myeloid leukemia (AML) are both ongoing.

"Data presented today provide important new insights into SNS-595's mechanism as a site-selective DNA intercalator and topoisomerase poison with selectivity for proliferating cells. Through its unique chemical structure and molecular mechanism, SNS-595 avoids common drug resistance pathways and may have advantages over other topoisomerase poisons," said Daniel C. Adelman, M.D., Senior Vice President, Development and Chief Medical Officer. "Taken together, these data support our ongoing clinical trials of SNS-595 in platinum-resistant ovarian cancer and acute myeloid leukemia, and provide compelling evidence for future studies of SNS-595 in indications such as breast cancer where topoisomerase II poisons are active."

Sunesis researchers conducted in vitro and cell-based studies elucidating SNS-595's mechanism of action. SNS-595 selectively intercalates DNA and poisons topoisomerase II, resulting in replication-dependent DNA damage, irreversi
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