Niraparib maintenance therapy fails to significantly extend OS in recurrent ovarian cancer
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Key takeaways:
- Median OS was 40.9 months with niraparib vs. 38.1 months with placebo among those with BRCA mutations and 31 months vs. 34.8 months among those without BRCA mutations.
- Researchers observed no new adverse events.
Niraparib did not significantly extend OS among women with recurrent ovarian cancer, according to long-term follow-up results of the ENGOT-OV16/NOVA trial presented at Society of Gynecologic Oncology Annual Meeting on Women’s Cancer.
A previously presented analysis of OS, a secondary endpoint of the trial, had been limited due to missing follow-up data on survival status and post-progression therapies.
“There are imbalances in post-progression therapy in the different groups, and missing data still exists on these post-progression therapies,” Ursula A. Matulonis, MD, director and chief of gynecologic oncology at Dana-Farber Cancer Institute, said in a press release. “And, the study was not powered for formal overall survival analyses, creating additional interpretation challenges.”
Other secondary endpoints showed a persistent treatment effect with niraparib (Zejula, GSK), a poly(ADP-ribose) polymerase (PARP) inhibitor, and researchers observed no new adverse events during the extended follow-up.
Background and methods
As Healio previously reported, the randomized phase 3 ENGOT-OV16/NOVA trial included 553 women with platinum-sensitive recurrent disease.
Researchers randomly assigned women to either 300 mg niraparib maintenance therapy or placebo once-daily, and stratified results based on germline BRCA mutation status. Overall, 203 women had germline BRCA mutations (niraparib, n = 138; placebo, n = 65) and 350 did not (niraparib, n = 234; placebo, n = 116).
The trial met the primary endpoint of PFS assessed by blinded independent central review. Researchers reported longer median PFS with niraparib in both the germline BRCA-mutant cohort (21 months vs. 5.5 months; HR = 0.27) and non-germline BRCA-mutant cohort (9.3 months vs. 3.9 months; HR = 0.45).
At SGO, Matulonis reported the final OS and long-term safety findings of the trial.
“For this updated analysis, a vital status collection procedure was completed to retrieve the last known alive status for 92 patients who had missing survival data,” Matulonis said during the presentation.
Median follow-up was more than 75 months for both cohorts and treatment groups.
At the time of data cutoff March 31, 2021, survival data were available for 540 patients (97.6%).
Findings
Results showed an overall OS maturity of 77.9%.
Median OS was 40.9 months with niraparib vs. 38.1 months with placebo among those with BRCA mutations (HR = 0.85; 95% CI, 0.61-1.2), and 31 months vs. 34.8 months among those without BRCA mutations (HR = 1.06; 95% CI, 0.81-1.37).
“Additional secondary endpoints, including chemotherapy-free interval, time to first and subsequent therapies, and PFS2 demonstrated a persistent treatment effect numerically in favor of niraparib in both of the subgroups,” Matulonis said during the presentation. “No new safety signals were observed with long-term follow-up.”
Implications
The findings underscore the importance of long-term follow-up of patients and also point to a continued need for research, according to researchers.
“Our patients with ovarian cancer are living longer and are thus receiving more therapies,” Matulonis said in the press release. “It is critical for trials to follow patients long-term for overall survival after they stop study treatment and to carefully record and chronicle post-study treatment therapies. Understanding the impact of PARP inhibitor therapy on post-progression treatment resistance is also an important area of research.”
References:
- Matulonis UA, et al. Final overall survival and long-term safety in the ENGOT-OV16/NOVA phase III trial of niraparib in patients with recurrent ovarian cancer. Presented at: Society of Gynecologic Oncology Annual Meeting on Women’s Cancer; March 25-28, 2023; Tampa, Florida.
- Trial’s long-term follow-up data shows no difference in overall survival among ovarian cancer patients who did and did not receive PARP inhibitor maintenance therapy (press release). Available at: www.newswise.com/articles/trial-s-long-term-follow-up-data-shows-no-difference-in-overall-survival-among-ovarian-cancer-patients-who-did-and-did-not-receive-parp-inhibitor-maintenance-therapy. Published March 23, 2023. Accessed March 27, 2023.
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Matulonis UA, et al. Final overall survival and long-term safety in the ENGOT-OV16/NOVA phase III trial of niraparib in patients with recurrent ovarian cancer. Presented at: Society of Gynecologic Oncology Annual Meeting on Women’s Cancer; March 25-28, 2023; Tampa, Florida.
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