Olaparib monotherapy in advanced triple-negative breast cancer patients with homologous recombination deficiency and without germline mutations in BRCA1/2: The NOBROLA phase 2 study

PURPOSE: To evaluate olaparib in advanced triple negative breast cancer (TNBC) patients with homologous recombination deficiency (HRD) and no germline BRCA1/2 mutations (gBRCA1/2mut). METHODS: NOBROLA (NCT03367689) is a single-arm, open-label, multicenter, phase IIa trial, enrolling adult patients with advanced TNBC without gBRCA1/2mut and with HRD, who were treated with olaparib. The primary endpoint was clinical benefit rate (CBR) per RECIST v.1.1. RESULTS: Six of 114 patients were eligible and received olaparib. Median follow up was 8.5 months. CBR and overall response rate (ORR) were 50 % (95 % CI, 11.8-88.2). CONCLUSIONS: The observed results could prompt further investigation. TRIAL: ClinicalTrials.gov identifier NCT03367689.