( Interim Data from Phase 1 Clinical Tria...)Sunesis Pharmaceuticals Reports Positive Data From Studies of Two,Anti-Cancer Agents, SNS-595 and SNS-032, at the 12th Congress of,the European Hematology Association,Health

SOUTH SAN FRANCISCO, Calif., June 11, 2007 /PRNewswire-FirstCall/ -- Sunesis Pharmaceuticals, Inc. presented positive data from clinical studies of two of the company's anti-cancer product candidates, SNS-595 and SNS-032, at the 12th Congress of the European Hematology Association (EHA) in Vienna, Austria.

Interim Results from Sunesis' Phase 1 Study of SNS-595 in Acute Leukemias

Interim data from the company's ongoing Phase 1 clinical trial of SNS-595 in patients with relapsed and/or refractory acute leukemias continue to demonstrate SNS-595's anti-cancer activity when administered on either a weekly or twice-weekly schedule. To date, on the weekly schedule, five out of ten patients in the 50 mg/m2 and 60 mg/m2 dose cohorts experienced bone marrow blast reductions of more than 95 percent, including one complete remission with incomplete platelet recovery (CRp), one complete remission in a patient who demonstrated partial but incomplete recovery of normal hematopoietic blood elements (CRi) and one partial response (PR). Additionally, in the twice-weekly 40 mg/m2 dose cohort, one of three patients had blast reduction of more than 95 percent and that patient achieved a complete remission (CR). Several patients have gone on to receive and tolerate multiple courses of treatment with SNS-595.

The data presented from the Phase 1 clinical trial of SNS-595 show a correlation between plasma drug levels, modulation of a pharmacodynamic marker of biologic activity and clinical responses when treated with SNS-595. There is emerging evidence that clinical responses are observed when plasma concentrations of SNS-595 exceed and remain above a threshold level for approximately 20 hours per week of active treatment. The CR, CRp and CRi responses observed to date all had sustained blood levels above
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