Impact of Olaparib for Maintenance Monotherapy on Survival in Breast and Ovarian Cancer: A Systematic Review and Pooled Analysis of Published Trials

Purpose: To assess the efficacy and safety of Olaparib, a PARP inhibitor on progression-free survival (PFS), objective response rate (ORR) and overall survival (OS) in patients with breast and ovarian cancer. Methods: Research data from clinical trials through PubMed, Science Citation Index, Elsevier Science Direct and Cochrane Library of all published studies exploring the PFS, ORR or OS of Olaparib for maintenance monotherapy on survival in breast and ovarian cancer were analysed. Pooled estimates of the ORR, weighted medians of PFS and OS from all Olaparib were calculated. Assessment of quality and level of evidence was assigned by Cochrane guidelines and guidelines of Oxford Centre for Evidence-Based Medicine. Results: Data of 893 patients (731 olaparib; 162 control) from 6 trials, 2 randomised controlled trials and 4 non-randomised trials, were included. The overall median weighted PFS and OS in patients treated with Olaparib were 5.9 and 19.1 months, respectively. The pooled ORR was 25%. Olaparib showed a greater effect on PFS in patients with both wild-type BRCA and BRCA mutant gene. The most common toxicity were nausea and vomiting. Conclusions: Olaparib as maintenance monotherapy for breast and ovarian cancer is associated with promising outcomes including increased response rate and improved PFS. Its potential in clinical application is needed for further investigation in phase III trials.