Olaparib monotherapy for Asian patients with a germline BRCA mutation and HER2-negative metastatic breast cancer: OlympiAD randomized trial subgroup analysis

The OlympiAD Phase III study (NCT02000622) established the clinical benefits of olaparib tablet monotherapy (300mg twice daily) over chemotherapy treatment of physician's choice (TPC) in patients with a germline BRCA1/2 mutation (gBRCAm) and human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer who had received <= 2 chemotherapy lines in the metastatic setting. Here, we report pre-specified analyses of data from Asian (China, Japan, Korea and Taiwan) patients in the study. All patients were randomized 2:1 to olaparib tablets (300mg twice daily) or single-agent chemotherapy TPC (21-day cycles of either capecitabine, eribulin or vinorelbine). The primary endpoint was progression-free survival assessed by blinded independent central review. The prevalence of gBRCAm in the OlympiAD Asian subgroup screened for study recruitment was 13.5%. Patient demographics and disease characteristics of the Asian subgroup (87/302 patients) were generally well balanced between treatment arms. Asian patients in the olaparib arm achieved longer median progression-free survival, assessed by blinded independent central review, versus the chemotherapy TPC arm (5.7 vs 4.2 months; HR=0.53 [95% CI: 0.29-0.97]), which was consistent with findings in the global OlympiAD study population. Findings on secondary efficacy and safety/tolerability outcome measures in Asian patients were also similar to those observed in the global OlympiAD study population. The OlympiAD study was not powered to detect race-related differences between treatment groups; however, the consistency of our findings with the global OlympiAD study population suggests that previously reported findings are generalizable to Asian patients.