LAUSR

Introduction/Background Bevacizumab with chemotherapy followed by bevacizumab was approved in 2018 for the first-line (1L) treatment of patients with ovarian cancer (OC). However, little is known about the real-world experience of OC patients treated with bevacizumab. Methodology This US SEER-Medicare retrospective cohort study included females ≥66 years, with OC (stage II–IV) diagnosis between 2009 and 2015, who continued bevacizumab or observation alone after 4–10 cycles of 1L platinum-based chemotherapy with or without bevacizumab. The primary outcome was overall survival (OS), measured from 1L treatment initiation to death from any cause. Safety events of interest included thrombosis, hemorrhage, stroke, and gastrointestinal perforation. Inverse probability of treatment weighting (IPTW) incorporating 32 demographic and prognostic characteristics was used to ensure balance in baseline variables. Cox proportional hazards models with IPTW were used to compare outcomes. Results In this cohort (N=2262), 66 (3%) patients received bevacizumab maintenance. Mean age (±SD) was 74.6 (6.2) years, 89% were Stage III or IV, and 26.9% of patients had ≥1 comorbidity. Patients treated (preapproval) with 1L maintenance bevacizumab increased from 0.3% in 2009 to 4.1% in 2015. Compared to observation alone, median OS in patients treated with bevacizumab maintenance was 43.6 vs 37.9 months (adjusted hazard ratio [HR]=0.83 [95% CI: 0.50–1.36]). Among those who received >7 cycles of bevacizumab, OS was longer, though not significantly, compared to observation alone (aHR=0.62 [95% CI: 0.32–1.18]). Initiation of nonplatinum chemotherapy within 12 months occurred in 36.4% of observation only and 20.9% of bevacizumab maintenance patients. Compared to observation alone, specified safety events were not higher with bevacizumab maintenance, aHR: 0.94 [0.49–1.82]. Conclusion Survival among this small cohort of elderly OC patients in this real-world study is consistent with that observed in trials of 1L bevacizumab maintenance. First-line maintenance bevacizumab therapy appears to provide modest survival benefit. Disclosure G Adeboyeje, K Desai, S Iqbal, J He, M Monberg are employees of Merck Sharp & Dohme Corp. This study was funded by Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA.