Efficacy of Maintenance Olaparib for Patients with Newly Diagnosed Advanced Ovarian Cancer with a BRCA Mutation: Subgroup Analysis Findings from the SOLO1 Trial

PURPOSE In SOLO1, maintenance olaparib (300 mg twice daily) significantly improved progression-free survival (PFS) for patients with newly diagnosed BRCA1- and/or BRCA2-mutated advanced ovarian cancer compared with placebo (hazard ratio [HR], 0.30; 95% CI, 0.23 to 0.41; median not reached v 13.8 months). We investigated PFS in SOLO1 for subgroups of patients based on preselected baseline factors. PATIENTS AND METHODS Investigator-assessed PFS subgroup analyses of SOLO1 included clinical response after platinum-based chemotherapy (complete [CR] or partial response [PR]), surgery type (upfront or interval surgery), disease status after surgery (residual or no gross residual disease), and BRCA mutation status (BRCA1 or BRCA2). Additionally, we evaluated PFS in patients with stage III disease who underwent upfront surgery and had no gross residual disease. We also report objective response rate. RESULTS The risk of disease progression or death was reduced with olaparib compared with placebo by 69% (HR, 0.31; 95% CI, 0.21 to 0.46) and 63% (HR, 0.37; 95% CI, 0.24 to 0.58) in patients undergoing upfront or interval surgery; 56% (HR, 0.44; 95% CI, 0.25 to 0.77) and 67% (HR, 0.33; 95% CI, 0.23 to 0.46) in patients with residual or no residual disease after surgery; 66% (HR, 0.34; 95% CI, 0.24 to 0.47) and 69% in women with clinical CR or PR at baseline (HR, 0.31; 95% CI, 0.18 to 0.52); and 59% (HR, 0.41; 95% CI, 0.30 to 0.56) and 80% (HR 0.20; 95% CI, 0.10 to 0.37) in patients with a BRCA1 or BRCA2 mutation, respectively. CONCLUSION Patients with newly diagnosed advanced ovarian cancer achieve substantial benefit from maintenance olaparib treatment regardless of baseline surgery outcome, response to chemotherapy, or BRCA mutation type.