The benefit of Niraparib Maintenance may extend beyond the first progression in ovarian cancer
Maintenance treatment with niraparib may provide lasting benefit in patients with ovarian cancer, according to a presentation at the 2021 Virtual Congress on Gynecological Cancers of the European Society for Medical Oncology (ESMO).1
Updated phase 3 data showed a second benefit in progression-free survival (PFS2) in some patients who received niraparib, but there was no overall survival (OS) benefit with niraparib.
âThe final analysis of PFS2 indicated that the benefit of niraparib maintenance therapy extended beyond the first progression, but the overall survival data is difficult to interpret,â said Mansoor Raza Mirza, MD , from Copenhagen University Hospital in Denmark, which presented the data to the congress.
The ENGOT-OV16 / NOVA Phase 3 trial (ClinicalTrials.gov Identifier: NCT01847274) enrolled patients with recurrent epithelial cancer of the ovary, fallopian tubes, or primary peritoneum who had achieved a partial or complete with previous platinum-based chemotherapy.
There were 203 patients with the germ line BRCA mutations who were randomized to receive niraparib (n = 138) or placebo (n = 65) and 350 patients without these mutations who were randomized to receive niraparib (n = 234) or placebo (n = 116) in maintenance.
The first results of PFS were published in 2016.2 In the BRCA-mutant, the median PFS was 21.0 months with niraparib and 5.5 months with placebo (hazard ratio [HR], 0.27; 95% CI: 0.17-0.41; P <.001 in the group without>BRCA mutations, the median PFS was 9.3 months and 3.9 months, respectively (RR: 0.45; 95% CI: 0.34-0.61; P <.001>
Ultimately, PFS2 was significantly longer with niraparib than with placebo in patients with BRCA mutations (RR: 0.67; 95% CI: 0.479-0.948). There was a tendency to improve PFS2 with niraparib in patients without BRCA mutations, but this was not significant (HR, 0.81; 95% CI: 0.632-1.050).
In the final OS analysis, the mean follow-up was 5.6 years and there was no difference in OS between the niraparib and placebo groups.
In patients without BRCA mutations, the median OS was 31.1 months with niraparib and 36.5 months with placebo (RR: 1.10; 95% CI: 0.831-1.459). In patients with BRCA mutations, the median OS was 43.6 months and 41.6 months, respectively (HR, 0.93; 95% CI, 0.633-1.355).
Dr Mirza noted that the trial was not statistically powerful for OS and that the analysis was hampered by a high rate of study dropouts, subsequent use of PARP inhibitors, and missing data.
Treatment-emergent grade 3 or higher hematologic adverse events occurred most frequently in the first year of treatment with niraparib and decreased significantly over 2-3 years, Dr. Mirza reported.
There were 13 cases of myelodysplastic syndromes / acute myeloid leukemia in the niraparib arm and 3 cases in the placebo arm.
Disclosures: This research was supported by Tesaro, Inc., Myriad Genetics, Inc., and others. Dr Mirza has declared affiliations with biotechnology, pharmaceutical and / or device companies. Please see the original reference for a full list of disclosures.
- Mirza M. Long-term safety and secondary efficacy criteria in the phase 3 ENGOT-OV16 / NOVA trial of niraparib in relapsed ovarian cancer. Presented at: ESMO Virtual Congress on Gynecological Cancers; June 25-26, 2021.
- Mirza MR, Monk BJ, Herrstedt J, et al. Maintenance therapy with niraparib in relapsing platinum-sensitive ovarian cancer. N Engl J Med. 2016; 375: 2154-2164. doi: 10.1056 / NEJMoa1611310