Trial results for a Phase 3 study (NCT04475939) investigating niraparib plus pembrolizumab as maintenance therapy for advanced/metastatic non-small cell lung cancer (NSCLC) were posted on ClinicalTrials.gov on 2026-05-01. The study found no significant difference in progression-free survival (PFS) or overall survival (OS) between the combination therapy and pembrolizumab alone, with a hazard ratio of 1.0 (95% CI: 0.79 to 1.27) and a p-value of 0.502 for the primary analysis.
Background
The study investigated the combination of niraparib and pembrolizumab as maintenance therapy for participants with advanced or metastatic non-small cell lung cancer (NSCLC). Participants had previously achieved stable disease, partial response, or complete response after standard first-line platinum-based induction chemotherapy with pembrolizumab.
Trial design
The study (NCT04475939) was a Phase 3, multicenter, randomized, double-blind, placebo-controlled trial. It enrolled 666 participants with advanced or metastatic non-small cell lung cancer (NSCLC). The trial compared niraparib plus pembrolizumab against placebo plus pembrolizumab as maintenance therapy. Participants had achieved stable disease, partial response, or complete response following standard of care first-line platinum-based induction chemotherapy with pembrolizumab.
Key results
The trial evaluated progression-free survival (PFS) and overall survival (OS).
- In the complete and partial response (CR/PR) population, median PFS was 5.55 Months for both the Niraparib + Pembrolizumab group and the Placebo + Pembrolizumab group.
- For the intent-to-treat (ITT) population, median PFS was 4.40 Months for Niraparib + Pembrolizumab and 4.37 Months for Placebo + Pembrolizumab.
- Median Overall Survival (OS) in the CR/PR population was 24.77 Months for Niraparib + Pembrolizumab compared to 32.49 Months for Placebo + Pembrolizumab.
- In the ITT population, median OS was 21.36 Months for Niraparib + Pembrolizumab versus 25.26 Months for Placebo + Pembrolizumab.
- Time to Progression (TTP) in the Central Nervous System (CNS) showed similar proportions of participants experiencing progression: 0.11 to 0.12 for Niraparib + Pembrolizumab, and 0.10 to 0.11 for Placebo + Pembrolizumab.
A Cox proportional hazard analysis for the primary outcome yielded a Hazard Ratio (HR) of 1.0 (95% Confidence Interval: 0.79 to 1.27) with a p-value of 0.502, indicating no statistically significant difference between the treatment arms for progression-free survival.
What this means
The results from this Phase 3 study indicate that adding niraparib to pembrolizumab as maintenance therapy for advanced or metastatic NSCLC did not significantly improve progression-free survival or overall survival compared to pembrolizumab alone. Median PFS values were nearly identical, and median OS was numerically lower in the combination arm. The hazard ratio of 1.0 and the p-value of 0.502 confirm that the addition of niraparib did not provide a statistically significant clinical benefit in this patient population.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT04475939, titled "Placebo-controlled Study Comparing Niraparib Plus Pembrolizumab Versus Placebo Plus Pembrolizumab as Maintenance Therapy in Participants With Advanced/Metastatic Non-Small Cell Lung Cancer," were posted on 2026-05-01 on clinicaltrials.gov.