SOUTH SAN FRANCISCO, Calif.–(BUSINESS WIRE)–Five
Prime Therapeutics, Inc. (NASDAQ: FPRX), a clinical-stage
biotechnology company focused on discovering and developing innovative
immuno-oncology protein therapeutics, today presented monotherapy data
from the dose escalation portion of the Phase 1a/1b clinical trial of
FPA150 in patients with advanced solid tumors. These data were presented
at the Developmental Immunotherapy and Tumor Immunobiology Poster
Session during the 2019 American Society of Clinical Oncology (ASCO)
Annual Meeting. The poster can be found on the Scientific Publications page
of the Five Prime Therapeutics website.
The data are the first presentation of FPA150 results and include safety
and pharmacokinetics results from the Phase 1a monotherapy dose
escalation portion of the study. The Phase 1a monotherapy portion of the
study is being conducted in patients with advanced solid tumors, and the
Phase 1b monotherapy expansion is enrolling patients with breast,
ovarian and endometrial tumors that overexpress B7-H4.
“FPA150 is a first-in-class B7-H4 antibody that blocks inhibitory
signaling to CD8 T cells and promotes the killing of B7-H4
overexpressing tumors through enhanced ADCC,” said Jasgit Sachdev, M.D.
and Director of Breast and Gynecologic Early Phase Trials at the
HonorHealth Research Institute. “It is promising to see in this study
that FPA150 was well tolerated at doses as high as 20mg/kg with no
dose-limiting toxicities.”
The open-label, multi-dose, multi-center Phase 1a dose escalation study
was conducted in patients with advanced-stage solid tumors regardless of
B7-H4 overexpression at monotherapy doses ranging from 0.01 to 20 mg/kg
every three weeks in an accelerated titration followed by 3+3 design and
in a separate dose exploration cohort in which patients with tumors that
overexpress B7-H4 were treated at doses of 3 or 10 mg/kg every three
weeks with mandatory pre- and on-treatment biopsies.
FPA150 monotherapy demonstrated a favorable safety profile with no
dose-limiting toxicities or treatment-related serious adverse events.
Evaluation of anti-tumor activity is ongoing. A recommended dose of 20
mg/kg every three weeks was selected based on safety and
pharmacokinetics.
“Rapid enrollment of this first-in-human study of a novel targeted agent
with checkpoint blockade and ADCC activity highlights the significant
unmet need in patients with advanced breast and gynecologic cancers,”
said Helen Collins, Chief Medical Officer of Five Prime Therapeutics.
“The preliminary data from the Phase 1a portion of this study, in
patients with tumors overexpressing B7-H4, support continued evaluation
of FPA150 in the monotherapy and in the anti-PD1 combination therapy
setting.”
Of the 29 patients in the Phase 1a portion of the study,18 had B7-H4
positive tumors based on medium or high immunohistochemistry (IHC)
scores, including 11 patients with advanced ovarian cancer. Of these,
one patient with ovarian cancer, who had been treated with seven prior
lines of therapy including anti-PD1 therapy, achieved a confirmed
partial response with a duration of 6.2 months.
Monotherapy Phase 1b expansion began in February 2019 and is enrolling
cohorts of patients with B7-H4 positive breast, ovarian and endometrial
cancers at a dose of 20 mg/kg every three weeks. A safety lead-in of the
combination of Keytruda® (pembrolizumab), a PD1 antibody, and
FPA150 has also begun enrolling patients with B7-H4 positive ovarian
cancer. The company expects to present preliminary efficacy results from
the monotherapy expansion cohorts and early safety results from the
FPA150-Keytruda combination at the European Society of Medical Oncology
in September 2019.
About FPA150
FPA150 is a novel, fully human, afucosylated monoclonal antibody
targeting B7-H4. B7-H4 overexpression is observed in multiple solid
tumors, including breast and gynecologic cancers. FPA150 is designed
with a dual mechanism of action: blocking the T cell checkpoint activity
of B7-H4 as well as promoting enhanced antibody-dependent cell-mediated
cytotoxicity (ADCC) against tumor cells expressing B7-H4.
About Five Prime Therapeutics
Five Prime Therapeutics, Inc. discovers and develops innovative protein
therapeutics to improve the lives of patients with serious diseases.
Five Prime’s product candidates have innovative mechanisms of action and
address patient populations in need of better therapies. The company
focuses on researching and developing immuno-oncology and targeted
cancer therapies paired with companion diagnostics to identify patients
who are most likely to benefit from treatment with Five Prime’s product
candidates. Five Prime has entered into strategic collaborations with
leading global pharmaceutical companies and has promising product
candidates in clinical and preclinical development. For more
information, please visit www.fiveprime.com or
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Cautionary Note on Forward-looking Statements
This press release contains forward-looking statements within the
meaning of the Private Securities Litigation Reform Act of 1995. Words
such as “may,” “will,” “expect,” “plan,” “anticipate,” “estimate,”
“intend” and similar expressions (as well as other words or expressions
referencing future events, conditions or circumstances) are intended to
identify forward-looking statements. These forward-looking statements
are based on Five Prime’s expectations and assumptions as of the date of
this press release. Each of these forward-looking statements involves
risks and uncertainties. Actual results may differ materially from these
forward-looking statements. Factors that may cause actual results to
differ from those expressed or implied in the forward-looking statements
in this press release are discussed in Five Prime’s filings with
the U.S. Securities and Exchange Commission, including the “Risk
Factors” contained therein. Except as required by law, Five Prime
assumes no obligation to update any forward-looking statements contained
herein to reflect any change in expectations, even as new information
becomes available.
Source: Five Prime Therapeutics, Inc.
Contacts
Martin Forrest
VP, Investor Relations & Corporate Communications
Five
Prime Therapeutics, Inc.
415-365-5625
martin.forrest@fiveprime.com