Investor and Media Inquiries: David Pitts Eric Bjerkholt Argot Partners Sunesis Pharmaceuticals Inc. 212-600-1902 650-266-3717 Sunesis Pharmaceuticals Reports Fourth Quarter and Full-Year 2011 Financial Results and Highl

Sunesis Pharmaceuticals Reports Fourth Quarter

and Full-Year 2011 Financial Results and Highlights

Sunesis to Host Conference Call Today at 10:30 AM Eastern Time

FRANCISCO, Calif., March 14, 2012 Sunesis Pharmaceuticals, Inc. (Nasdaq: SNSS) today reported financial results for the fourth quarter and year ended December 31, 2011. Net loss for the three months and year ended

December 31, 2011 was $8.7 million and $20.1 million, respectively. As of December 31, 2011, cash, cash equivalents and marketable securities totaled $44.1 million.

Thanks to the continuing successful execution of our strategic plan, Sunesis today is well positioned to capitalize on the value of vosaroxin, which we believe is the most advanced and promising

therapy in development for acute myeloid leukemia, said Daniel Swisher, Chief Executive Officer of Sunesis. In support of our future objectives, we have advanced all aspects of our pivotal vosaroxin program, including enrollment of 260

patients to date in our Phase 3 VALOR trial, which is progressing toward an interim analysis in the third quarter of this year; built significant financial flexibility, having executed a $25 million tranched debt financing facility in the fourth

quarter; and recently expanded our intellectual property estate, supporting commercial and development runway to 2030. We also entered into a partnership with Millennium Pharmaceuticals in March 2011 for the pan-Raf kinase inhibitor MLN2480, and

announced initiation of a Phase 1 study in September 2011.

Mr. Swisher added: 2012 promises to be a transformational year

for Sunesis, as we advance the VALOR trial through the interim analysis, progress towards regulatory filings and prepare the market for the planned launch of vosaroxin in AML.

Fourth Quarter 2011 and Recent Highlights

Financial Highlights

Conference Call Information

will host a conference call today, March 14th at 10:30 a.m. Eastern Time. The call can be accessed by dialing (866) 362-4666 (U.S. and Canada) or (617) 597-5313 (international), and entering passcode 99720867. To access the live audio

webcast, or the subsequent archived recording, visit the Investors and Media Calendar of Events section of the Sunesis website at www.sunesis.com. The webcast will be recorded and available for replay on the company s website

VALOR is a Phase 3, randomized, double-blind, placebo-controlled, pivotal trial in patients with first relapsed or refractory AML. The trial is expected

to enroll 450 evaluable patients at more than 110 leading sites in the U.S., Canada, Europe, Australia and New Zealand. The VALOR trial is currently enrolling patients, who are randomized one to one to receive either vosaroxin on days one and four

in combination with cytarabine daily for five days, or placebo in combination with cytarabine. Additionally, the VALOR trial employs an innovative, adaptive trial design that allows for a one-time sample size adjustment by the DSMB at the interim

analysis to maintain adequate power across a broader range of survival outcomes. The trial s primary endpoint is overall survival. For more information on the VALOR trial, please visit www.valortrial.com.

Vosaroxin is a first-in-class anti-cancer quinolone derivative (AQD), a class of compounds that has not been used previously for the treatment of cancer. Vosaroxin both intercalates DNA and inhibits

topoisomerase II, resulting in replication-dependent, site-selective DNA damage, G2 arrest and apoptosis.

AML is a rapidly progressing cancer of the blood characterized by the uncontrolled proliferation of immature blast cells in the bone marrow. The American

Cancer Society estimates there were 12,950 new cases of AML and approximately 9,050 deaths from AML in the U.S. in 2011. Additionally, it is estimated that the prevalence of AML across major global markets (U.S., France, Germany, Italy, Spain,

United Kingdom, and Japan) is over 50,000. AML is generally a disease of older adults, and the median age of a patient diagnosed with AML is about 67 years. AML patients with relapsed or refractory disease and newly diagnosed AML patients over 60

years of age with poor prognostic risk factors typically die within one year, resulting in an acute need for new treatment options for these patients.

About Sunesis Pharmaceuticals

Sunesis is a biopharmaceutical company focused on the

development and commercialization of new oncology therapeutics for the treatment of solid and hematologic cancers. Sunesis has built a highly experienced cancer drug development organization committed to advancing its lead product candidate,

vosaroxin, in multiple indications to improve the lives of people with cancer. For additional information on Sunesis, please visit http://www.sunesis.com.

This press release contains forward-looking statements, including statements related to Sunesis strategy, the sufficiency of Sunesis intellectual property estate and the patent exclusivity

period for vosaroxin in the United States and other jurisdictions, the design, conduct, progress and results of the VALOR trial and other clinical trials, the occurrence and timing of the DSMB interim analysis, the sufficiency of Sunesis

financial resources and availability of the second tranche under the loan facility with Oxford Finance LLC, Horizon Technology Finance Corporation and Silicon Valley Bank, vosaroxin s effects, efficacy, safety profile and commercial potential

as a single agent and in combination with cytarabine, the potential grant of orphan drug designation to vosaroxin by the European Commission, and the progress of the kinase collaboration programs. Words such as continuing,

advanced believe, progressing, promises, expects or expected, will, provides or providing, future objectives,

well-positioned, plan or planned, and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon Sunesis current expectations. Forward-looking

statements involve risks and uncertainties. Sunesis actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a results of these risks and uncertainties, which include, without

limitation, risks related to Sunesis need for substantial additional funding to complete the development and commercialization of vosaroxin, risks related to Sunesis ability to raise the capital that it believes to be accessible and is

required to fully finance the development and commercialization of vosaroxin, the risk that raising funds through lending arrangements may restrict our operations or produce other adverse results, the risk that Sunesis development activities

for vosaroxin could be otherwise halted or significantly delayed for various reasons, the risk that Sunesis clinical studies for vosaroxin may not demonstrate safety or efficacy or

lead to regulatory approval, the risk that data to date and trends may not be predictive of future data or results, the risk that Sunesis nonclinical studies and clinical studies may not

satisfy the requirements of the FDA or other regulatory agencies, risks related to the conduct of Sunesis clinical trials, risks related to the manufacturing of vosaroxin and supply of the active pharmaceutical ingredients required for the

conduct of the VALOR trial, the risk of third party opposition to granted patents related to vosaroxin, and the risk that Sunesis proprietary rights may not adequately protect vosaroxin. These and other risk factors are discussed under

Risk Factors and elsewhere in Sunesis Quarterly Report on Form 10-Q for the quarter ended September 30, 2011, Sunesis Annual Report on Form 10-K for the year ended December 31, 2011, when available, and

Sunesis other filings with the Securities and Exchange Commission. Sunesis expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change

in the company s expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.

SUNESIS and the logo are trademarks of Sunesis Pharmaceuticals, Inc.

SUNESIS PHARMACEUTICALS, INC.

CONSOLIDATED BALANCE SHEETS

Note 1: The consolidated balance sheet as of December 31, 2010 has been derived from the audited financial statements as

of that date included in the Company s Annual Report on Form 10-K for the year ended December 31, 2010.

SUNESIS PHARMACEUTICALS, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS)

(In thousands, except per share amounts)

Note 2: The consolidated statement of operations for the year ended December 31, 2010 has been derived from the audited

financial statements as of that date included in the Company s Annual Report on Form 10-K for the year ended December 31, 2010.