Sunesis Pharmaceuticals Announces Presentation of The Ohio State University-Sponsored Preclinical Study of BTK Inhibitor SNS-...
April 03 2017 - 8:00AM
Sunesis Pharmaceuticals, Inc. (Nasdaq:SNSS) today announced results
from an Ohio State University-sponsored preclinical study
evaluating the efficacy of non-covalent BTK inhibitor SNS-062 in
chronic lymphocytic leukemia (CLL) proprietary cell lines and
patient samples. The study demonstrated that, unlike ibrutinib,
SNS-062 inhibition of BTK signaling is unaffected by the presence
of the C481S mutation and may address acquired resistance to
covalent BTK inhibitors. The results are being presented today in a
poster session titled “Reversal of Drug Resistance” on Monday,
April 3, 2017 from 8:00 AM to 12:00 PM ET at the American
Association for Cancer Research Annual Meeting in Washington, D.C.
“B-cell receptor signaling is exceptionally
active in CLL and is vital for the proliferation and survival of
CLL cells, making BTK inhibition an effective target. However, a
subset of patients acquire resistance to ibrutinib, the current
standard of care BTK inhibitor,” said Amy Johnson, PhD, Associate
Professor, Hematology, The Ohio State University. “A key resistance
mechanism to covalent BTK inhibitors is a point mutation in the BTK
active site, converting cysteine 481 to serine, or C481S. In this
study, we demonstrate that SNS-062, which binds non-covalently to
BTK, is a potent inhibitor of BTK unaffected by the presence of the
C481S mutation. These findings support clinical investigation of
SNS-062 to address acquired resistance to covalent BTK inhibitors
in patients.”
“Preclinical and healthy volunteer data continue
to reveal a unique profile for SNS-062, one distinct from ibrutinib
and other covalently binding BTK inhibitors,” said Judy Fox, PhD,
Chief Scientific Officer of Sunesis. “SNS-062 has the potential to
become an important new treatment for CLL, addressing what is an
increasingly well-defined and prevalent unmet patient need.
With an active IND, we remain on track to dose the first patient in
our planned Phase 1B/2 study in patients with advanced B-cell
malignancies this quarter.”
For the study, primary CLL B-cells were isolated
from the whole blood of consenting patients with CLL. In
these cells, SNS-062 was found to decrease surface expression of
B-cell activation markers and patient CLL cell viability in a
dose-dependent manner, with BTK inhibition by SNS-062 comparable to
ibrutinib. Further, SNS-062 was found to inhibit BTK wild
type (WT) and BTK C481S, while ibrutinib and acalabrutinib show
reduced activity toward BTK C481S. SNS-062 has a unique kinase
selectivity profile, affecting a limited number of kinases outside
the TEC kinase family. SNS-062 was also found to diminish stromal
cell protection in patient CLL cells, an important observation
given the role of tumor microenvironment in this malignancy.
The poster (Poster Number 22, Abstract Number
1207, Convention Center, Halls A-C, Poster Section 6) titled
“SNS-062 demonstrates efficacy in chronic lymphocytic leukemia in
vitro and inhibits C481S mutated Bruton tyrosine kinase” is
available on the Sunesis website at www.sunesis.com.
About SNS-062
SNS-062 is a novel, second-generation BTK
inhibitor, a class of kinase inhibitors that selectively inhibits
the enzyme Bruton's tyrosine kinase (BTK). This target
mediates signaling through the B-cell receptor, which is critical
for adhesion, migration, proliferation and survival of normal and
malignant B-lineage lymphoid cells. Unlike other drugs in its
class, SNS-062 has a distinct kinase selectivity profile and binds
non-covalently to the BTK enzyme. This alternate binding site
potentially provides an opportunity to address the leading
resistance mechanism, a mutation in the enzyme’s binding site
required for covalent binding. In preclinical studies, SNS-062
demonstrated potent activity against Cys-481S mutated B-cell
malignancies, and has been studied in healthy subjects in a Phase
1A, randomized, double-blind, placebo-controlled dose-ranging study
to investigate the drug’s safety, pharmacokinetics, and
pharmacodynamics. With the reported successful study outcome,
SNS-062 is proceeding to a Phase 1B/2 study in patients with B-cell
malignancies.
About Sunesis
Pharmaceuticals
Sunesis is a biopharmaceutical company focused
on the development and commercialization of new oncology
therapeutics for the potential treatment of solid and hematologic
cancers. Sunesis has built a highly-experienced cancer drug
development organization committed to improving the lives of people
with cancer. Currently, the company is focused on pursuing
regulatory approval in Europe for its lead product candidate,
vosaroxin, for the treatment of relapsed or refractory acute
myeloid leukemia in patients aged 60 and older, as well as
advancing its novel kinase-inhibitor pipeline, which includes its
proprietary non-covalent BTK-inhibitor, SNS-062.
For additional information on Sunesis, please
visit http://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' corporate
objectives, the regulatory development, Sunesis’ response to Day
180 List of Outstanding Issues and the anticipated timing of a CHMP
decision, and potential approval of vosaroxin by the EMA, potential
collaborations and ability to commercialize vosaroxin
in Europe. Words such as “advancing,” “anticipate,” “expect,”
"potential,” “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 that Sunesis may not be able
to receive regulatory approval of vosaroxin in the U.S.
or Europe, that Sunesis' development activities for vosaroxin
could be otherwise halted or significantly delayed for various
reasons, risks related to Sunesis' need for substantial additional
funding to complete the development and commercialization of
vosaroxin and other product candidates, the risk that Sunesis'
clinical studies for vosaroxin or other product candidates,
including its pipeline of kinase inhibitors, 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 conduct of Sunesis' clinical trials,
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 vosaroxin and other product
candidates. These and other risk factors are discussed under "Risk
Factors" and elsewhere in Sunesis' Annual Report on Form 10-K for
the year ended December 31, 2016 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 Sunesis' expectations
with regard thereto or any change in events, conditions or
circumstances on which any such statements are based.
Investor and Media Inquiries:
David Pitts
Argot Partners
212-600-1902
Eric Bjerkholt
Sunesis Pharmaceuticals Inc.
650-266-3717
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