Talazoparib in patients with BRCA mutant metastatic breast or ovarian carcinoma: results of early access program

Introduction: Talazoparib is a strong PARP inhibitor with significant catalytic inhibition as well as the ability to cause PARP entrapment at DNA damage sites. It is one of the recommended treatments for individuals with BRCA-mutant advanced breast cancer, although research on its efficacy in advanced ovarian cancer is limited. The purpose of this study was to evaluate the efficacy of talazoparib in advanced breast and ovarian cancer patients with BRCA mutations. Materials and methods: Patients with advanced breast (HR + or TNBC) and ovarian cancer who had germline BRCA mutations were included in this multicenter, retrospective study. There were no exclusion criteria regarding treatment-line, metastatic sites or performance status. All patients received talazoparib treatment via early-access programme. The primary endpoint was PFS. Secondary endpoints were OS and ORR. Results: There were 47 and 42 patients in the breast cancer (BC) and ovarian cancer (OC) cohorts, respectively. In BC cohort, after median 13.6 months follow-up the median PFS was 6.5 months (5.0–8.1 months, 95% CI). In this heavily pretreated cohort, the ORR was 31.9% and the estimated 12-month OS rate was 73.6%. In OC cohort, the median follow up period was 13.7 months and the median PFS was 9.1 months (7.3–10.8 months, 95% CI). The ORR was 47.6% and the estimated 12-month OS rate was 75.9% in OC patients. Conclusion: Talazoparib may be an effective therapy option for patients with advanced BRCA-mutant breast cancer. In the absence of prospective phase 2/3 data, the outcomes of OC cohort may also considerably contribute to the literature on BRCA-mutant ovarian cancer.