Sunesis Launches Phase 3 VALOR Trial of Vosaroxin in AML

Sunesis Pharmaceuticals, Inc. (NASDAQ: SNSS) today announced that the first patient has been randomized and dosed with blinded study treatment in its pivotal Phase 3 VALOR trial of vosaroxin, the company's lead drug candidate, in combination with cytarabine in patients with first relapsed or refractory acute myeloid leukemia (AML). The VALOR trial is a multinational, randomized, double-blind, placebo-controlled, pivotal trial which is expected to enroll 450 evaluable patients at leading sites in the U.S., Canada, Europe, Australia and New Zealand.

"The initiation of VALOR marks the culmination of many years of work and is a gratifying moment for Sunesis in its ongoing efforts to develop a new therapeutic option for AML patients," stated Daniel Swisher, Chief Executive Officer of Sunesis. "AML is a challenging disease, especially for relapsed and refractory patients, yet in our robust Phase 2 program we have shown in this AML setting that vosaroxin plus a leading standard of care, cytarabine, exhibit a combination of efficacy and tolerability that has led to promising results. The support of key opinion leaders, top international trial sites, specialized service providers and a rigorously designed Phase 3 protocol should provide the VALOR trial with a strong foundation for operational success."

"Patients with relapsed or refractory AML have a poor prognosis and are often intolerant of or do not respond to currently available treatment options," said Farhad Ravandi, M.D., Associate Professor, Department of Leukemia, Division of Cancer Medicine, The University of Texas M. D. Anderson Cancer Center, and a principal investigator of VALOR. "Despite the unmet medical need, treatment standards have not appreciably changed in more than 30 years. Vosaroxin's differentiated treatment profile from the Phase 2 program is characterized by strong remission rates, low all-cause early mortality and long leukemia free survival, which have led to survival outcomes that compare favorably with published results for current treatment standards. The VALOR trial is a well designed, highly anticipated trial which should provide a clear understanding of vosaroxin's efficacy and safety profile when added to cytarabine in this disease setting."

Patients in the VALOR trial will be randomized one-to-one to receive in a blinded manner either vosaroxin or placebo on days one and four of each treatment cycle in combination with cytarabine daily for five days of each treatment cycle. The trial's primary endpoint is overall survival. The VALOR trial employs an adaptive design that provides for a single interim analysis by an independent Data and Safety Monitoring Board (DSMB) which will meet to examine pre-specified efficacy and safety data sets and decide whether to implement a one-time sample size adjustment of 225 additional evaluable patients to maintain adequate power across a broad range of clinically meaningful and statistically significant survival outcomes. The interim analysis by the DSMB is expected to take place in mid-2012. For more information on VALOR please visit www.valortrial.com.