Investor and Media Inquiries: Maeve Conneighton Argot Partners 212-600-1902 Willie Quinn Sunesis Pharmaceuticals Inc. 650-266-3716 Sunesis Pharmaceuticals Reports First Quarter 2019 Financial Results and Recent Highlight

Sunesis Pharmaceuticals Reports First Quarter 2019 Financial Results and Recent Highlights

Phase 1b/2 Trial of Vecabrutinib Advances into 200 mg Cohort

Sunesis to Host Conference Call Today at 4:30 PM Eastern Time

SOUTH SAN FRANCISCO, Calif., May 8, 2019 -- Sunesis Pharmaceuticals, Inc. (Nasdaq: SNSS) today reported financial results for the first quarter ended March 31, 2019. Loss from operations for the three months ended March 31, 2019 was $5.7 million. As of March 31, 2019, cash and cash equivalents totaled $24.8 million.

"We continue our focus on the execution of the Phase 1b/2 trial of vecabrutinib and are excited to announce that we have completed the safety evaluation period for the 100 mg cohort, enabling us to advance the trial into the 200 mg cohort," said Dayton Misfeldt, Interim Chief Executive Officer of Sunesis. "To date, vecabrutinib appears to be well tolerated in the context of disease, and we will be providing a clinical update on the study at the European Hematology Association annual meeting in June."

Mr. Misfeldt continued, "Underscoring our clinical progress is a strengthened financial position. We began the first quarter by completing an equity offering with leading biotechnology investors, extending our cash runway through important clinical milestones, and just last month we announced the refinancing of our debt on favorable terms through an agreement with Silicon Valley Bank, a vote of confidence in our pipeline and its potential from a premier debt provider for life science companies."

Financial Highlights

Conference Call Information

Sunesis will host a conference today at 4:30 p.m. Eastern Time. The call can be accessed by dialing (844) 296-7720 (U.S. and Canada) or (574) 990-1148 (international) and entering passcode 1396684. 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 for two weeks.

About Sunesis Pharmaceuticals

Sunesis is a biopharmaceutical company developing new targeted therapeutics for the treatment of hematologic and solid cancers. Sunesis has built an experienced drug development organization committed to improving the lives of people with cancer. The Company is focused on advancing its novel kinase inhibitor pipeline, with an emphasis on its oral non-covalent BTK inhibitor vecabrutinib. Vecabrutinib is currently being evaluated in a Phase 1b/2 study in adults with chronic lymphocytic leukemia and other B-cell malignancies that have progressed after prior therapies. The Company's proprietary PDK1 inhibitor SNS-510 is in preclinical development. PDK1 is a master kinase that activates other kinases important to cell growth and survival including members of the AKT, PKC, RSK, and SGK families. Sunesis is exploring strategic alternatives for vosaroxin, a late-stage investigational product for relapsed or refractory AML. Sunesis also has an interest in the pan-RAF inhibitor TAK-580 which is licensed to Takeda. TAK-580 is in a clinical trial for pediatric low-grade glioma.

For additional information on Sunesis, please visit www.sunesis.com.

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

This press release contains forward-looking statements, including statements related to Sunesis' continued development of vecabrutinib (SNS-062), including the timing of Phase 1b/2 trial of vecabrutinib and the therapeutic potential of vecabrutinib, further development and potential of its kinase inhibitor pipeline, and sufficiency of its cash resources and financial position. Words such as "appears", "expect," "look forward," "will" 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 result of these risks and uncertainties, which include, without limitation, the risk related to the timing or conduct of Sunesis' clinical trials, including the vecabrutinib Phase 1b/2 trial, the risk that Sunesis' clinical or preclinical studies for vecabrutinib, SNS-510 or other product candidate 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, risks related to the timing or conduct of Sunesis' clinical trials, that Sunesis' development activities for vecabrutinib or SNS-510 could be otherwise halted or significantly delayed for various reasons, that Sunesis may not be able to receive regulatory approval of vecabrutinib, or SNS-510 in the U.S. or Europe, and 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 vecabrutinib, SNS-510 and other product candidates. These and other risk factors are discussed under "Risk Factors" and elsewhere in Sunesis' Quarterly Report on Form 10-Q for the quarter ended March 31, 2019 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 reflect any change in Sunesis' expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.