Trial results for the Phase 3 study (NCT03522246) investigating nivolumab and rucaparib as maintenance treatment for newly diagnosed ovarian cancer were posted on ClinicalTrials.gov on 2025-06-24. The study revealed that the combination of rucaparib and nivolumab resulted in a median progression-free survival (PFS) of 15.0 months, which was shorter than the 20.2 months observed with rucaparib monotherapy.
Background
The study evaluated nivolumab and rucaparib as maintenance treatment following front-line platinum-based chemotherapy in patients with newly diagnosed FIGO Stage III-IV Epithelial Ovarian Cancer, Primary Peritoneal cancer, or Fallopian Tube Cancer.
Trial design
The Phase 3 study (NCT03522246) was a randomized, multinational, double-blind, dual placebo-controlled trial that enrolled 1097 participants. It investigated rucaparib and nivolumab as maintenance treatment in patients with newly diagnosed FIGO Stage III-IV Epithelial Ovarian Cancer, Primary Peritoneal cancer, or Fallopian Tube Cancer who had responded to front-line platinum-based chemotherapy. The study included arms evaluating rucaparib plus nivolumab (Arm A), rucaparib plus placebo (Arm B), and placebo plus placebo (Arm D).
Key results
Key results from the study focused on progression-free survival (PFS). For the comparison of rucaparib monotherapy versus placebo, investigator-assessed PFS showed:
- In one analysis, rucaparib plus placebo (Arm B) demonstrated a median PFS of 28.7 months, compared to 11.3 months for placebo plus placebo (Arm D).
- In another analysis, rucaparib plus placebo (Arm B) showed a median PFS of 20.2 months, versus 9.2 months for placebo plus placebo (Arm D).
Blinded Independent Central Review (BICR) for PFS also supported this, with rucaparib plus placebo (Arm B) achieving a median PFS of 25.9 months, compared to 9.1 months for placebo plus placebo (Arm D).
Statistical analyses for these comparisons yielded a Hazard Ratio (HR) of 0.47 (95.0% CI: 0.31 to 0.72) with a p-value of 0.0004, and an HR of 0.52 (95.0% CI: 0.4 to 0.68) with a p-value of 0.0001, both indicating a significant benefit for rucaparib monotherapy over placebo.
However, when comparing the combination therapy to rucaparib monotherapy, investigator-assessed PFS showed:
- Rucaparib plus nivolumab (Arm A) had a median PFS of 15.0 months.
- Rucaparib plus placebo (Arm B) had a median PFS of 20.2 months.
This comparison resulted in an HR of 1.29 (95.0% CI: 1.08 to 1.53) with a p-value of 0.0038, indicating that the addition of nivolumab to rucaparib was associated with a shorter PFS.
What this means
The trial results suggest that rucaparib monotherapy significantly extends progression-free survival in patients with newly diagnosed ovarian cancer following front-line platinum-based chemotherapy, compared to placebo. However, the addition of nivolumab to rucaparib maintenance therapy was associated with a statistically significant reduction in median PFS compared to rucaparib monotherapy. This finding indicates that combining nivolumab with rucaparib in this setting may not provide additional benefit and could potentially be detrimental to PFS.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT03522246, titled "A Study in Ovarian Cancer Patients Evaluating Rucaparib and Nivolumab as Maintenance Treatment Following Response to Front-Line Platinum-Bas," were posted on 2025-06-24 on clinicaltrials.gov.