PROSPECTUS SUPPLEMENT SUMMARY
This summary highlights certain information about us, this offering and information appearing elsewhere in this prospectus supplement,
in the accompanying prospectus and in the documents we incorporate by reference. This summary is not complete and does not contain all of the information that you should consider before making an investment decision. To fully understand this
offering and its consequences to you, you should read this entire prospectus supplement and the accompanying prospectus carefully, including the factors described under the headings Risk Factors in this prospectus supplement beginning on
page
S-5
and in our Quarterly Report on Form
10-Q
for the quarterly period ended September 30, 2018, together with any free writing prospectus we have authorized
for use in connection with this offering and the financial statements and other information incorporated by reference in this prospectus supplement and the accompanying prospectus.
About Sunesis
Sunesis is a biopharmaceutical company focused on the development of new therapeutics for the treatment of solid and hematologic cancers. Our primary activities since incorporation have been conducting
research and development internally and through corporate collaborators,
in-licensing
and
out-licensing
pharmaceutical compounds and technology, conducting clinical
trials and raising capital.
Our lead program is vecabrutinib, formerly known as
SNS-062,
a
non-covalent
inhibitor of Brutons Tyrosine Kinase, or BTK. Vecabrutinib is being studied in a Phase 1b/2 clinical trial in
B-cell
malignancies. In January 2017, we announced our Investigational New Drug, or IND, application with the U.S. Food and Drug Administration, or FDA, for vecabrutinib had become effective. In July 2017, we
announced the dosing of the first patient in a Phase 1b/2 study to assess the safety and activity in patients with advanced
B-cell
malignancies after two or more prior therapies, including ibrutinib or another
covalent BTK inhibitor where approved for the disease, and including patients with BTK C481 mutations. In connection to the dosing of the first patient, we also made a milestone payment of $2.5 million to Biogen Idec MA, Inc., or Biogen, under
the licensing agreement. The Phase 1b portion of the study is a dose escalation component that will proceed to define a maximum tolerated dose and/or a recommended Phase 2 dose. In January 2019, we announced that we had completed the 50 mg cohort of
the Phase 1b portion of the study and had opened the 100 mg cohort. Upon identifying the Phase 2 dose, the Phase 2 portion will further explore clinical activity and safety in disease- and mutation-specific cohorts, including patients with and
without BTK C481 mutations.
We are also developing
SNS-510,
a PDK1 inhibitor licensed
from Millennium Pharmaceuticals, Inc., a wholly-owned subsidiary of Takeda Pharmaceutical Company Limited, or Takeda. We acquired from Takeda global commercial rights to several potential
first-in
class,
preclinical inhibitors of the novel target PDK1, including
SNS-510.
We are currently characterizing
SNS-510
in preclinical pharmacology studies.
We are in a collaboration with Takeda for the development
of TAK-580 (formerly
MLN2480),
an
oral pan-RAF inhibitor,
which is under investigation for pediatric
low-grade
glioma.
We licensed worldwide development and commercialization rights to vosaroxin from Sumitomo Dainippon Pharma Co., Ltd. in 2003. Vosaroxin,
our product candidate for the potential treatment of acute myeloid leukemia, is an anticancer quinolone derivative a class of compounds that has not been used previously for the treatment of cancer. We conducted a Phase 3,
multinational, randomized, double-blind, placebo-controlled trial of vosaroxin in combination with cytarabine in patients with relapsed or refractory Acute Myeloid Leukemia, or AML. This trial did not meet its primary endpoint of demonstrating a
statistically significant improvement in overall survival. We announced on May 1, 2017 the withdrawal of our Marketing Authorization Application, or MAA, for vosaroxin. We are evaluating strategic alternatives to continue development and
commercialization for vosaroxin.