PARPi monotherapy as first-line maintenance following chemotherapy plus bevacizumab in advanced ovarian cancer.

e17601 Background: Chemotherapy (CT) + bevacizumab is a standard-of-care option for first-line (1L) treatment for patients with advanced ovarian cancer (AOC). Real-world approaches to 1L maintenance (1LM) treatment include, among others, bevacizumab monotherapy or switching to poly(ADP-ribose) polymerase inhibitor (PARPi) monotherapy after completing 6–9 cycles of induction CT + bevacizumab. Methods: We identified 61 patients with AOC from the US-based, deidentified Integra PrecisionQ database who received 1LM bevacizumab monotherapy (n=27) or PARPi monotherapy (n=34) after 1L CT + bevacizumab initiated between July 1, 2019, and March 31, 2021, and followed them until the data cut-off of March 31, 2022. Using the start of 1LM therapy as the index date, we examined patient characteristics, time to next treatment or death (TTNT; often used as a real-world proxy for progression-free survival), and overall survival (OS) for these two treatment groups. Results: For patients who received 1LM bevacizumab, the median age was 69 years, 89% had Eastern Cooperative Oncology Group (ECOG) performance status 0–1, 63% had Stage III disease at index, and only 1 (4%) had a recorded/documented homologous recombination deficiency (HRd)-positive tumor. Of the 34 patients who switched to 1LM PARPi monotherapy, 21 (62%) received olaparib, 12 (35%) niraparib, and 1 (3%) rucaparib. The median age of these patients was 63.5 years, 94% had ECOG performance status 0–1, 62% had Stage III disease at index date, and 47% had HRD+ tumors. For patients who switched to 1LM PARPi monotherapy, the median TTNT was 10.8 months (mo) and 97% were still alive at the 12-month mark. For patients who continued with 1LM bevacizumab, the median TTNT was 4.9 mo and 81% remained alive at the 12-month mark. Conclusions: This study suggests that switching to maintenance with PARPi monotherapy following induction CT + bevacizumab is a viable option for the treatment of AOC. A higher prevalence of HRd patients switching to PARPi monotherapy may indicate clinician preference for PARPi monotherapy in biomarker-selected subgroups, and further analysis is needed to examine which patients are most likely to benefit from switch maintenance. Funding: GSK215281. [Table: see text]