Pfizer Inc. announced that the US Food and Drug Administration accepted for filing and granted Priority Review designation to the company’s New Drug Application for talazoparib. The submission is based on results from the EMBRACA trial, which evaluated talazoparib versus chemotherapy in patients with germline (inherited) BRCA-mutated (gBRCAm), HER2-negative locally advanced or metastatic breast cancer (MBC). Talazoparib is an investigational, once-daily, oral poly ADP ribose polymerase (PARP) inhibitor. The European Medicines Agency has also accepted the Marketing Authorization Application for talazoparib in this patient population.

“Women with a hereditary BRCA mutation are typically diagnosed with breast cancer at a younger age than the overall breast cancer population and have limited treatment options when they develop advanced disease,” said Mace Rothenberg, M.D., chief development officer, Oncology, Pfizer Global Product Development. “Today’s filing acceptances are just the latest example of the success of Pfizer’s precision medicine approach to drug development, in this case targeting the faulty DNA damage repair process associated with BRCA mutations. We are now one step closer to offering a potential alternative to chemotherapy for these patients.”

The FDA grants Priority Review designation to medicines that may offer significant advances in treatment or may provide a treatment where no adequate therapy exists. The Prescription Drug User Fee Act (PDUFA) goal date for a decision by the FDA is in December 2018.

The pivotal, randomized EMBRACA trial evaluated once-daily talazoparib compared to physician’s choice chemotherapy (capecitibine, eribulin, gemcitabine or vinorelbine) in 431 patients with an inherited BRCA1/2 mutation and locally advanced or metastatic triple negative (TNBC) or hormone receptor-positive (HR+)/HER2- breast cancer. The study met its primary endpoint, demonstrating superior progression-free survival (PFS) with talazoparib versus chemotherapy. The PFS benefit was consistent across prespecified subgroups, including those who had a history of brain metastases, patients previously treated with chemotherapy, TNBC patients and those with HR+ disease. Grade =3 adverse reactions with talazoparib that occurred with a frequency of at least 10% were anemia (35%), neutropenia (17%) and thrombocytopenia (17%).

Talazoparib is an investigational anti-cancer medicine called a PARP (poly ADP ribose polymerase) inhibitor. Preclinical studies suggest that talazoparib is highly potent and has a dual mechanism of action, with the potential to induce tumor cell death by blocking PARP enzyme activity and trapping PARP on the sites of DNA damage. Talazoparib is currently being evaluated in advanced gBRCAm breast cancer and early triple negative breast cancer as well as DNA damage repair (DDR)-deficient prostate cancer and in combination with immunotherapy in various solid tumor types. Talazoparib has not been approved by any regulatory authorities for the treatment of any disease.

BRCA1 and BRCA2 are human genes that produce proteins involved in DNA repair. When either of these genes is altered or mutated, DNA repair may not progress correctly. This can lead to the development of certain types of cancer such as breast cancer. BRCA mutations can be hereditary (germline) or occur spontaneously (somatic). Together, BRCA1 and BRCA2 mutations account for about 25 to 30 per cent of hereditary breast cancers and about 5 to 10 per cent of all breast cancers.  It is estimated that about 72 percent of people who inherit a BRCA1 mutation and about 69 per cent who inherit a BRCA2 mutation will develop breast cancer by age 80. Epidemiologic studies indicate that individuals with gBRCAm breast cancer are diagnosed at a median age of 40-45, which is approximately 20 years younger than the overall breast cancer population.

BRCA-mutated breast cancer is considered metastatic if it has spread beyond the breast to other parts of the body, including the bones, liver, lung or brain. There is currently no cure for metastatic breast cancer, the most advanced stage (stage IV) of the disease. The goal of treatment is to delay or slow disease progression while maintaining quality of life.