The poly (ADP-ribose) polymerase (PARP) inhibitor olaparib is approved as maintenance therapy in patients with platinum-sensitive relapsed ovarian cancer who are in complete or partial response to platinum-based chemotherapy. However, for patients with stable disease (SD), the efficacy of maintenance olaparib remains unknown. A recent phase 2 study has shown that, compared with maintenance with platinum-based chemotherapy alone, progression-free survival (PFS) can be significantly prolonged in patients with platinum-sensitive relapsed ovarian cancer who receive olaparib plus platinum-based chemotherapy followed by maintenance olaparib.1 Here, Oza and colleagues performed a retrospective post-hoc analysis of outcomes in patients with SD on scans at the end of chemotherapy and the efficacy of maintenance olaparib versus observation.2
In an open-label, multicenter trial, patients with platinum-sensitive relapsed serous ovarian cancer, primary peritoneal cancer, or fallopian tube cancer were randomized to receive platinum-based chemotherapy alone, without maintenance olaparib, or olaparib plus platinum-based chemotherapy followed by maintenance olaparib. The most recent scan from randomization up to 2 weeks after the final dose of carboplatin was used to assess the best objective Response Evaluation Criteria in Solid Tumors 1.1 response at the end of chemotherapy using blinded independent central review.
At the end of chemotherapy, 24 (29.6%) patients in the olaparib + chemotherapy group and 21 (25.9%) patients who received chemotherapy alone had SD as their best response (timing of the scan ranged from 2.10 months before to 0.49 months after the last dose of carboplatin). Median PFS, calculated from the end of chemotherapy, was 8.74 months with maintenance olaparib at a standard dose versus 5.4 months without maintenance olaparib (hazard ratio, 0.50; 95% confidence interval, 0.25-1.00; P = .046). Delayed responses following the end of chemotherapy occurred in 4 patients who received maintenance olaparib (16.7%; 2 complete and 2 partial responses) and 3 patients without maintenance olaparib (14.3%; all partial responses). The number of lines of prior chemotherapy did not appear to be predictive of PFS benefit.
Together, these results suggest that maintenance treatment with the PARP inhibitor olaparib is associated with prolonged PFS compared with observation alone in patients with advanced ovarian cancer with SD following platinum-based therapy. The number of lines of prior chemotherapy did not appear to be predictive of PFS benefit.
