The following article features coverage from the SGO 2022 Annual Meeting on Women’s Cancer. Click here to read more of Cancer Therapy Advisor’s conference coverage.

First-line maintenance with niraparib at an individualized starting dose (ISD) significantly improved progression-free survival (PFS) in patients with advanced ovarian cancer, according to results of the PRIME study.  

The median PFS was 16.5 months longer with niraparib than with placebo, and the PFS benefit was observed regardless of biomarker status or postoperative residual disease status.

These results were presented at the SGO 2022 Annual Meeting on Women’s Cancer by Ning Li, MD, of the National Cancer Center of China.

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Dr Li noted that niraparib is approved as first-line maintenance in ovarian cancer based on results of the PRIMA study ( Identifier: NCT02655016), which showed a PFS improvement with niraparib regardless of biomarker status.

However, the PRIMA study did not include patients with stage III disease who had no residual disease after primary debulking surgery. In addition, an ISD was used in about 35% of patients on the study.

In the PRIME study ( Identifier: NCT03709316), researchers evaluated niraparib maintenance with an ISD in all patients. The trial enrolled patients with stage III-IV ovarian cancer who had undergone primary or interval cytoreductive surgery with any postoperative residual disease status. The patients had also responded to first-line platinum-based chemotherapy.

The cohort included 384 patients who were randomly assigned to receive niraparib (n=255) or placebo (n=129) for 36 months or until disease progression or unacceptable toxicity. Baseline characteristics were well balanced across the arms.

The median follow-up was 27.5 months. In the intent-to-treat population, the median PFS was 24.8 months with niraparib and 8.3 months with placebo. Niraparib reduced the risk of progression or death by 55% (hazard ratio [HR], 0.45; 95% CI, 0.34-0.60; P <.001).

The PFS benefit was consistent across all prespecified subgroups. In particular, Dr Li pointed out that niraparib provided a PFS benefit regardless of germline BRCA status.

Among patients with germline BRCA mutations, the median PFS was not reached in patients receiving niraparib and was 10.8 months in patients assigned to placebo (HR, 0.40; 95% CI, 0.23-0.68; P<.001). In patients without germline BRCA mutations, the median PFS was 19.3 months with niraparib and 8.3 months with placebo (HR, 0.48; 95% CI, 0.34-0.67; P <.001).

An analysis limited to patients without germline BRCA mutations showed a PFS benefit with niraparib in patients with or without homologous recombination deficiency (HRD).

In patients with HRD, the median PFS was 24.8 months with niraparib and 11.1 months with placebo (HR, 0.58; 95% CI, 0.36-0.93; P =.022). In patients without HRD, the median PFS was 14.0 months with niraparib and 5.5 months with placebo (HR, 0.41; 95% CI, 0.25-0.65; P <.001).

The overall survival data are immature, but there is a trend in favor of niraparib, Dr Li said. The median overall survival has not been reached in either treatment arm.

With the ISD, the safety profile of niraparib was improved, Dr Li said. The median relative dose intensity was 100% for both niraparib and placebo.

Treatment-emergent adverse events (TEAEs) were manageable and consistent with the PARP inhibitor class, according to Dr Li. Dose reductions in all patients were numerically lower than in previous niraparib trials. TEAEs leading to dose reductions of niraparib occurred in 40.4% of patients in the PRIME trial, compared with 70.9% of patients in the PRIMA trial.

Disclosures: This research was supported by Zai Lab. Dr Li reported having no conflicts of interest.

Read more of Cancer Therapy Advisor’s coverage of SGO 2022 by visiting the conference page.


Li N, Zhu J, Yin R, et al. Efficacy and safety of niraparib as maintenance treatment in patients with newly diagnosed advanced ovarian cancer using an individualized starting dose (PRIME Study): A randomized, double-blind, placebo-controlled, phase 3 trial. Presented at SGO 2022; March 18-21, 2022. Abstract LBA 5