CAMBRIDGE, Mass., Oct. 30, 2013 /PRNewswire/ -- Merrimack
Pharmaceuticals, Inc. (NASDAQ:MACK) today announced results of a
global, Phase 2, open-label, randomized study of MM-121 in
combination with paclitaxel versus paclitaxel alone in patients
with platinum-resistant or platinum-refractory advanced ovarian
cancers.
This study did not meet the primary endpoint of progression free
survival in the overall population. The hazard ratio (HR) for
progression free survival (PFS) was 1.0 [95% CI 0.74 - 1.4].
Ongoing analysis of a pre-specified set of biomarkers
mechanistically linked to ErbB3 signaling identified a potential
subpopulation of patients benefiting from MM-121 treatment in
combination with paclitaxel. When using a combination of two
biomarkers, the hazard ratio for PFS was 0.37 [95% CI 0.2 - 0.8] in
the 34% of patients who were biomarker positive. The hazard ratio
for PFS in the biomarker negative population was 1.54 [95% CI 1.0 -
2.4].
An overall increase in all grades of gastrointestinal
toxicities, including diarrhea (73.6% vs. 42.5%), vomiting (31.4%
vs. 18.8%) and other mucosal toxicities such as rhinitis (7.1% vs.
1.3%), epistaxis (23.6% vs. 17.5%), stomatitis (22.1% vs. 10.0%)
and mucosal inflammation (22.1% vs. 1.3%), were observed in the
combination as compared to paclitaxel alone, the majority of which
were mild to moderate in severity. An increase in the pulmonary
embolism rate was observed with the combination of MM-121 and
paclitaxel (5.0% vs. 1.2%). No enhancement of paclitaxel-related
peripheral neuropathy was reported with the combination.
"This unique study design lays the groundwork for future
translational studies in ovarian cancer. The rapid enrollment into
this study was a testament to the commitment of patients and
physicians to advance our knowledge and improve upon available
therapies in advanced ovarian cancers," said Dr. Akos Czibere, Clinical Director of the MM-121
program at Merrimack. "These data are a step forward for women with
ovarian cancer."
"Research at Merrimack and elsewhere has shown that
ligand-driven signaling through ErbB3 is one way in which cancer
cells become resistant to therapy," said Gavin MacBeath, Ph.D., Co-Founder and Vice
President of Translational Research at Merrimack. "MM-121 was
designed to block this pathway. We are particularly encouraged by
the biomarker findings in this trial, which are consistent with our
preclinical hypotheses. This gives us increased confidence in our
network biology platform and in our translational program at
Merrimack."
This study was designed to evaluate whether MM-121 in
combination with paclitaxel is more effective than paclitaxel
alone, based on progression free survival. Patients were randomized
at a 2:1 ratio for MM-121 in combination with paclitaxel versus
paclitaxel alone. The study was conducted in the United Stated and
Europe, and 223 patients were
randomized. Patients enrolled in this study had locally
advanced/metastatic or recurrent epithelial ovarian cancer,
fallopian tube cancer or primary peritoneal cancer, had received at
least one prior platinum-based chemotherapy regimen, and were
platinum-resistant or refractory. The full data from the study will
be presented at a future conference.
MM-121, in partnership with Sanofi, is also being evaluated in
second line ER/PR+ metastatic breast cancer, ER/PR+ neoadjuvant
breast cancer, triple-negative neoadjuvant breast cancer and
non-small cell lung cancer.
About MM-121
MM-121 is a fully human monoclonal antibody that targets ErbB3,
a cell surface receptor implicated in tumor growth and survival. By
inhibiting ErbB3 signaling, MM-121 is designed to restore
sensitivity, delay resistance and enhance the anti-tumor effect of
a combination therapy partner. Sanofi and Merrimack entered into an
exclusive, global license and collaboration agreement for MM-121 in
2009.
About Merrimack Pharmaceuticals, Inc.
Merrimack is a biopharmaceutical company discovering, developing
and preparing to commercialize innovative medicines paired with
companion diagnostics for the treatment of cancer. Merrimack
applies its systems biology-based approach to biomedical research
throughout the research and development process. Merrimack
currently has six oncology therapeutics in clinical
development.
Forward-Looking Statement
To the extent that statements contained in this press release
are not descriptions of historical facts, they are forward-looking
statements reflecting the current beliefs and expectations of
management made pursuant to the safe harbor provisions of the
Private Securities Litigation Reform Act of 1995, as amended.
Forward-looking statements include any statements about Merrimack's
strategy, future operations, future financial position and future
expectations and plans and prospects for Merrimack, and any other
statements containing the words "anticipate," "believe,"
"estimate," "expect," "intend," "may," "plan," "predict,"
"project," "target," "potential," "will," "would," "could,"
"should," "continue," and similar expressions. In this press
release, Merrimack's forward-looking statements include statements
about the potential effectiveness of MM-121 in combination with
paclitaxel in certain patient populations or subpopulations, its
ability to develop a predictive diagnostic and its ability to
translate clinical data into future clinical success. Such
forward-looking statements involve substantial risks and
uncertainties that could cause Merrimack's clinical development
programs, future results, performance or achievements to differ
significantly from those expressed or implied by the
forward-looking statements. Such risks and uncertainties include,
among others, the uncertainties inherent in the initiation of
future clinical trials, availability of data from ongoing clinical
trials, expectations for regulatory approvals and other matters
that could affect the availability or commercial potential of
Merrimack's drug candidates or companion diagnostics. Merrimack
undertakes no obligation to update or revise any forward-looking
statements. Forward-looking statements should not be relied upon as
representing Merrimack's views as of any date subsequent to the
date hereof. For a further description of the risks and
uncertainties that could cause actual results to differ from those
expressed in these forward-looking statements, as well as risks
relating to Merrimack's business in general, see the "Risk Factors"
section of Merrimack's Quarterly Report on Form 10-Q filed with the
Securities and Exchange Commission (SEC) on August 8, 2013 and other reports Merrimack files
with the SEC.
SOURCE Merrimack Pharmaceuticals, Inc.