Olaparib maintenance therapy in patients with platinum-sensitive, relapsed serous ovarian cancer and a BRCA mutation: Overall survival adjusted for postprogression poly polymerase inhibitor therapy. Maintenance treatment with the oral poly polymerase inhibitor olaparib in Study 19 significantly improved progression-free survival in comparison with a placebo for patients with platinum-sensitive, relapsed serous ovarian cancer with a BRCA1/2 mutation , but an interim analysis revealed no statistically significant overall survival benefit.