PRIMA / ENGOT-OV26
Extended PARP maintenance to women without BRCA mutations, but the survival benefit did not materialise on longer follow-up.
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.
Setting
Newly diagnosed advanced ovarian cancer at high risk of relapse, any BRCA/HRD status: niraparib maintenance vs placebo
Phase
Phase 3
Sponsor
GSK (Tesaro)
Registry
Headline result
PFS HR 0.62 overall, 0.43 HRD-positive; final OS HR 1.01.
Reported
2019
Enrolled
733
Replication
ATHENA-MONO (rucaparib) reproduced the all-comers PFS gain; no all-comers OS benefit has been shown for any PARP inhibitor.
In plain words
What these results mean for people, not percentages
Progression-free survival (HRD-positive)primarysurrogate endpoint
- Median 21.9 vs 10.4 months with Niraparib compared with Placebo; about 11.5 months longer for half the group.
- A median is a midpoint: half the people did better than this and half did worse, so it is not a prediction for any one person.
- Put another way, the treated group had about 57 percent lower chance of the event at any given time (hazard ratio 0.43, likely range 0.31 to 0.59).
Progression-free survival (overall)primarysurrogate endpoint
- Median 13.8 vs 8.2 months with Niraparib compared with Placebo; about 5.6 months longer for half the group.
- A median is a midpoint: half the people did better than this and half did worse, so it is not a prediction for any one person.
- Put another way, the treated group had about 38 percent lower chance of the event at any given time (hazard ratio 0.62, likely range 0.5 to 0.76).
Be careful
- This is a surrogate endpoint: it measures the cancer being controlled or absent on scans and tests, which often, but not always, translates into living longer.
- These results apply to the people the trial enrolled: Newly diagnosed advanced ovarian cancer at high risk of relapse, any BRCA/HRD status: niraparib maintenance vs placebo. People in a different situation may not see the same effect.
- The trial selected people by a biomarker (BRCA); the result should not be assumed for people whose cancer does not have it.
Numbers are from the trial as recorded here; see the source links in the table below. This is orientation, not medical advice: ask your team how closely the trial population matches you.
733 participants enrolled.
Progression-free survival (HRD-positive)primary
HR 0.43 (0.31–0.59)
Niraparib
21.9 mo
Placebo
10.4 mo
| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Progression-free survival (HRD-positive)primary | Niraparib | — | 21.9 months | 0.43 (0.31–0.59) | — | link |
| Placebo | — | 10.4 months | ||||
| Progression-free survival (overall)primary | Niraparib | 487 | 13.8 months | 0.62 (0.5–0.76) | — | link |
| Placebo | 246 | 8.2 months |
Replication
ATHENA-MONO (rucaparib) reproduced the all-comers PFS gain; no all-comers OS benefit has been shown for any PARP inhibitor.