Olaparib versus chemotherapy treatment of physician’s choice in patients with a germline BRCA mutation and HER2-negative metastatic breast cancer (OlympiAD): Efficacy in patients with visceral metastases.

1052Background: The OlympiAD study showed a significant progression-free survival (PFS) benefit for olaparib over chemotherapy treatment of physician’s choice (TPC) in patients with HER2-negative metastatic breast cancer (mBC) and a germline BRCA mutation (gBRCAm; HR 0.58, 95% CI 0.43–0.80). Objective response rate (ORR) was 59.9% in the olaparib arm and 28.8% in the TPC arm. Prognosis may vary by location of metastases, so we investigated the overall efficacy of olaparib vs TPC in mBC patients with specific sites of visceral metastasis. Methods: OlympiAD was a randomized Phase III study in patients with HER2-negative mBC and a gBRCAm who had ≤2 chemotherapy lines for mBC (NCT02000622). Patients were randomized 2:1 to olaparib tablet monotherapy (300 mg bd) or single-agent TPC (capecitabine, eribulin or vinorelbine). Cox proportional hazard models were used for these post-hoc analyses. Results: The study was not powered to detect differences in treatment effect between subgroups, and results should be int...