Background: PARP inhibitor (PARPi) and bevacizumab have been integrated into the first-line (1L) maintenance therapy for patients (pts) with ovarian cancer (OC). However, due to adverse events, the rate of PARPi maintenance discontinuation was 12% in the SOLO1 clinical trial. We aimed to better understand the rate and cause of maintenance therapy discontinuation in real-world practice. Methods: This retrospective cohort study was conducted using de-identified electronic health record (EHR)–derived data from the nationwide Flatiron Health electronic health database. From January 1, 2016, to February 29, 2020, data were obtained for pts with newly diagnosed stage III/IV epithelial OC who received primary debulking surgery followed by 6–9 cycles of 1L platinum-based chemo or neoadjuvant chemo followed by interval debulking surgery. Index date was the end of 1L systemic therapy. Results: Of 675 pts with stage III/IV OC who underwent primary systemic therapy, 144 (21.3%) received 1L maintenance therapy and were included in the analysis. Mean age was 65.0 y. Most pts were treated in community practice (93.1%), had ECOG score of 0–1 at diagnosis (81.3%), and were shown to be BRCA wild type (66.7%). Bevacizumab was the most common 1L maintenance therapy (n = 69, 47.9%), followed by olaparib (n = 46, 31.9%), paclitaxel (n = 18, 12.5%), rucaparib (n = 10, 6.9%), and gemcitabine (n = 1, 0.7%). Overall, 34 (23.6%) pts discontinued 1L maintenance therapy. The most common reason for discontinuation was disease progression (n = 19, 13.2%), followed by treatment-related toxicity (n = 13, 9.0%; Table). Of 56 pts who received PARPi (olaparib or rucaparib) 1L maintenance therapy, 21 (37.5%) pts discontinued treatment: 11 (19.6%) because of disease progression, 9 (16.0%) treatment-related toxicity, and 1 for other reasons. Conclusions: In pts with advanced OC who received 1L maintenance therapy in clinical practice, disease progression was the most common reason for maintenance therapy discontinuation. The rates of toxicity-related discontinuations were comparable with those reported in clinical trials.

^aIncludes pts who received PARPi, bevacizumab, paclitaxel, or gemcitabine as 1L maintenance therapy.