NOVA clinical trial data outcomes were superior to the real-world outcomes for niraparib, highlighting the critical need for better understanding of variables impacting poly (ADP-ribose) polymerase (PARP) inhibitor outcomes in clinical practice.
Niraparib, a PARP inhibitor, is approved as maintenance treatment in patients with platinum-sensitive, recurrent ovarian cancer.
The eligibility criteria for the use of niraparib in the real-world practice are more lenient than those set forth in the NOVA trial; therefore, real-world outcomes are bound to differ from those observed in clinical trial patients.1 The best therapeutic strategy after progression on PARP inhibitors is unclear, and the relationship between probability of response to platinum and platinum-free interval could be altered after treatment with a PARP inhibitor. To probe this further at the European Society of Gynaecological Oncology 2020 Virtual Conference, Douglas Cartwright and colleagues retrospectively analyzed real-world use of niraparib and compared it with the criteria and outcomes of the NOVA trial.
Retrospective data were collected from between June 2017 and September 2019 for all women receiving maintenance niraparib for BRCA–wild-type, platinum-sensitive relapsed ovarian cancer. Electronic records were used to capture data on response to prior platinum-based chemotherapy, median progression-free survival (PFS) after first and subsequent platinum treatment, PARP inhibitor treatment cycle number, hematologic toxicities, dose, and time from the start of subsequent therapy to disease progression or death (PFS2I).
In the specified time frame, 37 patients received niraparib. Median follow-up was 16 months (range, 5.7-37 months). Although demographics were comparable with previously published cohorts, only 11% had a complete response (CR) to previous treatment with platinum therapy and 59% had a partial response (PR), compared with 50% CR and 50% PR observed in the NOVA trial.1
At the time of data collection, 95% of patients had progressed on niraparib. The median PFS with niraparib was 4.4 months, compared with 9.3 months in the NOVA study. Better outcomes were observed in patients who met the NOVA trial radiologic and serologic response criteria; they had a median PFS of 5.0 months compared with 3.9 months. Subsequent therapy was administered to 31 patients. For platinum-sensitive disease, the median PFS2I was 5.8 months; it was 3.5 months for platinum-resistant disease.
The clinical trial data were superior to the real-world outcomes for niraparib treatment. Whereas in this real-world study, patients had better outcomes if they had met NOVA trial eligibility criteria, these findings are poorer than those reported in the clinical trial. In both platinum-sensitive and platinum-resistant settings, post-PARP inhibitor treatment outcomes are unexpectedly inferior. This highlights the critical need to identify differences between clinical trials and clinical practice, so these tactics can be effectively incorporated into the real-world setting and treatment of PARP inhibitor–resistant disease.
Source: Cartwright D, et al. Int J Gynecol Cancer. 2020;30(4_suppl). Abstract 510.
Reference
1. Mirza MR, et al. N Engl J Med. 2016;375:2154-2164.