Niraparib as First-Line Maintenance Therapy in Patients with Stage III Ovarian Cancer and No Visible Residual Disease: AR1ZE Real-World Study

Introduction: Niraparib was approved for first-line (1L) maintenance (1LM) treatment of patients with advanced epithelial ovarian cancer (EOC) following the PRIMA/ENGOT-OV26/GOG-3012 (PRIMA) trial. PRIMA was restricted to patients at higher risk of progression (excluded stage III EOC with no visible residual disease [NVRD] after primary cytoreductive surgery [PCS]). This retrospective study evaluated the potential impact of excluding stage III EOC with NVRD from PRIMA by assessing real-world treatment outcomes following 1LM niraparib monotherapy in this patient population.

Methods: Data from a US-nationwide electronic health record-derived deidentified database comprised adult patients diagnosed with stage III/IV EOC who received 1L platinum-based chemotherapy and initiated niraparib 1LM monotherapy (01Jan2017-28Feb2023). Patients were classified as PRIMA-like (EOC with higher-risk prognostic factors for disease progression) or stage III disease with NVRD after PCS. Real-world time to next treatment (rwTTNT) and progression-free survival (rwPFS), assessed from the end date of 1L platinum-based chemotherapy, were measured via Kaplan-Meier methods.

Results: Among 453 patients who received niraparib 1LM (PRIMA-like cohort, n = 390; stage III NVRD cohort, n = 63), median follow-up from index was 14.9 (interquartile range [IQR], 7.3-25.1) and 18.4 (IQR, 9.3-29.1) months in the PRIMA-like and stage III NVRD cohorts, respectively. Median rwTTNT was significantly longer in the stage III NVRD cohort (22.5 [95% confidence interval (CI), 17.3-not reached] months) than in the PRIMA-like cohort (11.7 [95% CI, 10.8-12.9] months; P < 0.001). Median rwPFS in the stage III NVRD cohort (25.2 [95% CI, 12.6-not reached] months) was more than double that in the PRIMA-like cohort (10.1 [95% CI, 9.1-11.9] months; P < 0.001).

Conclusions: In the stage III NVRD cohort, rwTTNT and rwPFS were significantly longer than in the PRIMA-like cohort, consistent with clinical expectation. Results suggest niraparib clinical benefit may have been underestimated in PRIMA because of the exclusion of patients with stage III EOC with NVRD after PCS.