# PRIMA / ENGOT-OV26

Source: https://onco.cc/trials/prima/  
OnCo record `prima` (Trial). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Extended PARP maintenance to women without BRCA mutations, but the survival benefit did not materialise on longer follow-up.

## Summary

PFS 13.8 vs 8.2 months overall (HR 0.62) and 21.9 vs 10.4 months in HRD-positive disease (HR 0.43; NEJM 2019), leading to an all-comers first-line maintenance approval in 2020. The final overall survival analysis (2024) showed no OS difference (HR 1.01 overall), and the HR-proficient subgroup's benefit was small, prompting label debates and a shift toward HRD-guided use.

## Fields

- Kind: Trial
- Status: mixed
- Last checked: 2026-09-07
- Registry id: NCT02655016
- Phase: 3
- Setting: Newly diagnosed advanced ovarian cancer at high risk of relapse, any BRCA/HRD status: niraparib maintenance vs placebo
- Sponsor: GSK (Tesaro)
- Enrolled: 733
- Result: PFS HR 0.62 overall, 0.43 HRD-positive; final OS HR 1.01.
- Outcomes: Progression-free survival (HRD-positive): Niraparib 21.9 months vs Placebo 10.4 months, HR 0.43; Progression-free survival (overall): Niraparib 13.8 months vs Placebo 8.2 months, HR 0.62
- Replication: ATHENA-MONO (rucaparib) reproduced the all-comers PFS gain; no all-comers OS benefit has been shown for any PARP inhibitor.

## Sources

- ClinicalTrials.gov NCT02655016: https://clinicaltrials.gov/study/NCT02655016
- NEJM 2019: https://www.nejm.org/doi/full/10.1056/NEJMoa1910962

## Connected records

- cancers: [High-grade serous ovarian cancer](https://onco.cc/cancers/high-grade-serous-ovarian-cancer/), [Ovarian cancer](https://onco.cc/cancers/ovarian/), [Platinum-sensitive ovarian cancer](https://onco.cc/cancers/platinum-sensitive-ovarian-cancer/)
- technologies: [HRD genomic scar scores (GIS, LOH, HRDetect)](https://onco.cc/technologies/hrd-genomic-scar-scores/), [PARP inhibitors](https://onco.cc/technologies/parp-inhibitor/)
- targets: [PARP](https://onco.cc/targets/parp/)
- drugs: [myChoice CDx](https://onco.cc/drugs/mychoice-cdx/), [Niraparib](https://onco.cc/drugs/niraparib/)
- companies: [LYSA (The Lymphoma Study Association)](https://onco.cc/companies/lysa/)
- terms: [Homologous recombination deficiency (HRD)](https://onco.cc/terms/hrd/)
- people: [Antonio González-Martín](https://onco.cc/people/antonio-gonzalez-martin/)
- ideas: [ctDNA-guided duration of PARP maintenance](https://onco.cc/ideas/idea-ctdna-guided-parp-duration/)
- key papers: [PRIMA: niraparib maintenance in newly diagnosed advanced ovarian cancer](https://onco.cc/key-papers/paper-prima-niraparib-nejm-2019/)

---
JSON: https://onco.cc/api/v1/entities/prima.json