Abstract
544 Background: Ovarian cancer (OC) accounts for 1.1% of all cancers and is the fifth leading cause of cancer-related death in women in the US. Poly(ADP-ribose) polymerase inhibitors (PARPi) are targeted therapies that induce synthetic lethality in tumor cells with homologous recombination deficiencies, including BReast CAncer gene (BRCA) mutations. Bevacizumab is a monoclonal antibody targeting vascular endothelial growth factor (VEGF) ligand to inhibit angiogenesis. Active surveillance (AS) is close monitoring of patients with OC without providing treatment. Both maintenance therapy and AS require frequent surveillance to achieve optimal outcomes. Previous studies have shown that maintenance therapy with PARPi and/or bevacizumab are effective treatment strategies for patients with advanced stage OC, however, they are often underutilized by physicians (Gogineni V et al. J Cancer 2021;12(1):38-53). Methods: This retrospective study accessed the Ontada iKnowMed database to review the charts of patients who initiated platinum-based chemotherapy (PBC) in the first-line (1L) setting between January 1, 2018–December 31, 2020. Follow-up data for patients were collected through September 30, 2021. Kaplan-Meier estimates were used to compare utilization of maintenance therapy versus AS following 1L PBC for real-world progression-free survival (rwPFS) and overall survival (OS). Results: Following 1L PBC, 239 (39.8%) patients received maintenance therapy (56.5% received PARPis, 34.3% received bevacizumab and 9.2% received PARPi and bevacizumab) and 315 (52.5%) received AS. Median (min, max) follow-up time from initial diagnosis was 20.1 (2.2, 43.3) months for patients who received AS and 20.0 (4.4, 44.2) months for patients who received 1L maintenance therapy. Mean (standard deviation [SD]) age was 62.4 (12.0) and 65.8 (12.9) years for the maintenance and AS groups, respectively. Biomarker testing was not available in >40% of patients. Observed median rwPFS was 26.9 months (95% confidence interval [CI]: 21.3, not reached) for patients who received 1L maintenance therapy and 11.3 months (95% CI: 9.5, 13.0) for patients who received AS (log rank p<0.0001). Whilst observed median OS was not reached for either group, OS probabilities were 95.7%, 88.3%, and 82.4% at 1 year, 2 years, and 3 years respectively for patients who received 1L maintenance therapy and 85.9%, 71.5%, and 58.0% for patients who received AS. Conclusions: Despite previous studies demonstrating the benefits of maintenance therapy, <50% of patients in this study received 1L maintenance therapy following 1L PBC. These results show that maintenance therapies can improve rwPFS and OS in patients with advanced OC compared to AS. Therefore, there is a need to better understand maintenance therapy provider preferences and/or challenges. Funding: GSK 217225.