1096 Beyond trials: olaparib’s real-world data in platinum-sensitive relapsed ovarian cancer – multicenter experience from Portugal

Introduction/Background Despite European Medicines Agency approval, Olaparib reimbursement for BRCA-mutated ovarian cancer patients in Portugal only began in January 2022 and September 2019 for first and second-line maintenance treatment. This delay impacted national implementation and the associated learning curve for toxicities. This study provides real-world evidence to assess if phase III trial benefits effectively translate into clinical practice. Methodology In this retrospective multicenter study, 59 relapsed OC patients, treated with Olaparib as maintenance in six Portuguese centers, were included. Clinical data at diagnosis and recurrence before and after Olaparib treatment were collected. Primary objectives included efficacy and safety analysis, calculating median progression-free survival (PFS) and overall survival (OS) from Olaparib treatment initiation to radiologically confirmed relapse and death or last contact, respectively. Results Of the 59 patients, 29% were > 65yo, 76% were BRCA mutated, 54% received Olaparib maintenance at first relapse, and 63% had a platinum-free interval > 12 months. Median PFS was 12 months (95% CI: 8.4–15.6), with significantly better outcomes in patients with BRCA mutations (mPFS 13 months versus 4 months, Log-rank p= 0.007). Median OS was 28 months (95% CI: 21.2–34.7). Upon disease progression, 39 out of 42 patients underwent subsequent line of chemotherapy (ssq): median of 2 lines (1–4); 62% platinum-based chemotherapy; median PFS of ssq chemotherapy was 5 months (95% CI: 3.8–6.2), with comparable outcomes regardless of platinum use (log-rank p = 0.426). Toxicity of any grade occurred in 69% of patients, leading to dose reductions in 46% and three permanent discontinuations. Conclusion This is the first multicenter study to demonstrate the efficacy and safety of Olaparib's real-world performance in relapsed setting in Portugal. The findings underscore the need for continued research and training, emphasizing the ongoing learning curve that clinicians face in effectively managing treatment-related toxicities, and the need for faster and widespread access to innovative treatments. Disclosures Observational ESR study sponsored by AstraZeneca. The sponsor had no role in the design, data collection, analysis, interpretation, or decision to submit for publication. No fees were provided to the investigators for their involvement in the study.