FPA150 is a novel B7-H4 antibody that possesses both T cell immune checkpoint blockade and antibody-dependent cellular cytotoxicity (ADCC) activities. FPA150 demonstrates dose-dependent anti-tumor activity in vivo as a monotherapy and elicits complete tumor regressions in preclinical tumor models when given in combination with PD-1 blockade. Five Prime is currently studying FPA150 in a Phase 1 monotherapy trial in patients with solid tumors that overexpress B7-H4.
“Our monoclonal B7-H4 antibody, FPA150, appears to possess both T cell
checkpoint blockade activity and enhanced ADCC,” said
B7-H4 is a member of the B7-family of T cell immune checkpoint ligands and shares significant homology with other family members, including PD-L1 and PD-L2. B7-H4 is expressed in several human tumors such as carcinomas of the bladder, breast, ovary and endometrium, and its expression tends to correlate with poor prognosis. B7-H4 is also a documented T cell immune checkpoint inhibitory ligand capable of directly suppressing T cell responses.
In Investigational New Drug (IND)-enabling pharmacokinetics (PK) and toxicity studies, FPA150 demonstrated a suitable PK profile and was generally well tolerated. A B7-H4 immunohistochemistry (IHC) assay is in development for clinical use as a companion diagnostic to help identify the patients who might benefit most from this treatment.
Five Prime is studying FPA150 in a Phase 1 monotherapy trial with a dose-escalation phase in patients with solid tumors, followed by dose expansion in pre-specified cohorts in tumor types based on B7-H4 expression levels. The initial targeted tumors are advanced or metastatic breast, ovarian, endometrial and bladder cancers.
FPA150 is a novel, fully human, afucosylated monoclonal antibody targeting B7-H4. B7-H4 expression is observed in multiple solid tumors, including breast, bladder, ovarian and endometrial cancers, and has been documented to correlate with poor prognosis. FPA150 is designed with a dual mechanism of action: blocking the T cell checkpoint activity of B7-H4 as well as delivering potent ADCC against tumor cells expressing B7-H4. FPA150 is currently being studied in a Phase 1 clinical trial in advanced or metastatic breast, ovarian, endometrial and bladder cancers.
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Five Prime Therapeutics, Inc.
Heather Rowe, 415-365-5737
Senior Director, Investor Relations and Corporate Communications