Clinical outcomes and subsequent therapy in patients with platinum-sensitive recurrent ovarian cancer deriving long-term benefit from maintenance niraparib: a subgroup analysis of the GEICO-88R study.

Objective: To describe characteristics, clinical outcomes, and subsequent therapies in patients receiving long-term maintenance niraparib in the Spanish expanded-access program.

Methods: This retrospective observational study (NCT04546373) described patient characteristics, treatment exposure, and clinical outcomes in patients receiving maintenance niraparib for high-grade serous platinum-sensitive recurrent ovarian cancer. Subgroup analyses in patients receiving niraparib for ≥1 year ("long-term responders") were prespecified; additional post hoc analyses explored outcomes in patients treated for ≥2 years ("sustained long-term responders").

Results: In this real-world population of 316 patients (predominantly BRCA wildtype), 107 (34%) were long-term responders and 61 (19%) were sustained long-term responders. Compared with patients discontinuing niraparib within 1 year, the long-term responders subgroup included a higher proportion with primary debulking surgery and no residual disease after cytoreductive surgery and a lower proportion with >4 prior lines of systemic therapy, International Federation of Gynecology and Obstetrics stage IV disease, measurable disease at niraparib initiation, and Eastern Cooperative Oncology Group performance status 1. Tolerability was similar regardless of treatment duration. After discontinuing niraparib, the most frequently administered regimens were platinum-based. Response rates to the first post-niraparib line were 37% to 44%, and median progression-free survival was 7.0 months in non-long-term responders and 7.9 months in long-term responders. Median overall survival was 56.9 months in long-term responders (49.1 months' median follow-up) and was not reached in the sustained long-term responders subgroup.

Conclusions: Mature results from the GEICO-88R study continue to support the effectiveness and tolerability of maintenance niraparib in platinum-sensitive recurrent ovarian cancer. A subset of patients experienced long-term disease control. The efficacy of subsequent treatment appeared similar irrespective of niraparib duration.