OlympiAD extended follow-up for overall survival and safety: Olaparib versus chemotherapy treatment of physician's choice in patients with a germline BRCA mutation and HER2-negative metastatic breast cancer.

Background: In the Phase III OlympiAD study, olaparib significantly prolonged progression-free survival versus chemotherapy treatment of physician's choice (TPC) in patients with germline BRCA-mutated (gBRCAm), human epidermal growth factor receptor 2-negative metastatic breast cancer (mBC). In the final pre-specified analysis (64% maturity), median overall survival (OS) was 19.3 months for olaparib and 17.1 months for TPC (P = 0.513). Post-hoc extended follow-up, 25.7 months longer than previously reported for OS, is reported.

Patients And Methods: Patients with gBRCAm, human epidermal growth factor receptor 2-negative mBC, who had received ≤2 lines of chemotherapy for metastatic disease, were randomised 2:1 to olaparib (300 mg bid) or TPC. During extended follow-up, OS was analysed every 6 months using the stratified log-rank test (overall population) and Cox proportional hazards model (pre-specified subgroups).

Results: In the overall population (302 patients; 76.8% maturity), median OS was 19.3 months for olaparib and 17.1 months for TPC (hazard ratio 0.89, 95% confidence interval 0.67-1.18); median follow-up was 18.9 and 15.5 months, respectively. Three-year survival was 27.9% for olaparib versus 21.2% for TPC. With olaparib, 8.8% of patients received study treatment for ≥3 years versus none with TPC. In first-line mBC, median OS was longer for olaparib than TPC (22.6 versus 14.7 months; hazard ratio 0.55, 95% confidence interval 0.33-0.95) and 3-year survival was 40.8% for olaparib versus 12.8% for TPC. No new serious adverse events related to olaparib were observed.

Conclusions: OS was consistent with previous analyses from OlympiAD. These findings support the possibility of meaningful long-term survival benefit with olaparib, particularly in first-line mBC.