EMBER-3
An oral SERD that works alone in ESR1-mutant tumours and, combined with abemaciclib, doubles progression-free time in everyone regardless of mutation.
Three arms (imlunestrant n=331; standard ET n=330; imlunestrant + abemaciclib n=213). In ESR1-mutant tumours imlunestrant alone: PFS 5.5 vs 3.8 months (HR 0.62). Imlunestrant + abemaciclib vs imlunestrant: PFS 9.4 vs 5.5 months (HR 0.57; updated 10.9 vs 5.5, HR 0.59), with benefit irrespective of ESR1 status. Updated analysis (SABCS 2025): ESR1-mutant OS 34.5 vs 23.1 months for monotherapy vs standard ET. FDA approved imlunestrant (Inluriyo) 25 September 2025 for ESR1-mutant disease.
Setting
ER+/HER2- advanced breast cancer after ≥1 endocrine line: imlunestrant vs standard endocrine therapy, and imlunestrant + abemaciclib vs imlunestrant
Phase
Phase 3
Sponsor
Eli Lilly
Registry
Headline result
PFS HR 0.62 (ESR1-mutant, monotherapy); HR 0.57 (combination vs monotherapy).
Reported
2024
Enrolled
874
Replication
Monotherapy effect consistent with EMERALD and VERITAC-2; the combination result is the first randomised evidence for oral SERD + CDK4/6 after prior CDK4/6 exposure.
In plain words
What these results mean for people, not percentages
Progression-free survival, ESR1-mutant (imlunestrant vs standard ET)primarysurrogate endpoint
- Median 5.5 vs 3.8 months with Imlunestrant compared with Standard endocrine therapy; about 1.7 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 0.46 to 0.82).
- 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.
Progression-free survival (imlunestrant + abemaciclib vs imlunestrant)primarysurrogate endpoint
- Median 10.9 vs 5.5 months with Imlunestrant + abemaciclib compared with Imlunestrant; about 5.4 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 41 percent lower chance of the event at any given time (hazard ratio 0.59, likely range 0.46 to 0.75).
- 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.
Overall survival, ESR1-mutant (imlunestrant vs standard ET), updatedsurvival endpoint
- Median 34.5 vs 23.1 months with Imlunestrant compared with Standard endocrine therapy; about 11.4 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.
- Overall survival counts deaths from any cause, so it is the most direct measure of whether a treatment helps people live longer.
Be careful
- These results apply to the people the trial enrolled: ER+/HER2- advanced breast cancer after ≥1 endocrine line: imlunestrant vs standard endocrine therapy, and imlunestrant + abemaciclib vs imlunestrant. People in a different situation may not see the same effect.
- The trial selected people by a biomarker (HER2); 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.
874 participants enrolled.
Progression-free survival, ESR1-mutant (imlunestrant vs standard ET)primary
HR 0.62 (0.46–0.82) · p <0.001
Imlunestrant
5.5 mo
Standard endocrine therapy
3.8 mo
Progression-free survival (imlunestrant + abemaciclib vs imlunestrant)primary
HR 0.59 (0.46–0.75) · p <0.001
Imlunestrant + abemaciclib
10.9 mo
Imlunestrant
5.5 mo
Overall survival, ESR1-mutant (imlunestrant vs standard ET), updated
Imlunestrant
34.5 mo
Standard endocrine therapy
23.1 mo
| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Progression-free survival, ESR1-mutant (imlunestrant vs standard ET)primary | Imlunestrant | — | 5.5 months | 0.62 (0.46–0.82) | <0.001 | link |
| Standard endocrine therapy | — | 3.8 months | ||||
| Progression-free survival (imlunestrant + abemaciclib vs imlunestrant)primary | Imlunestrant + abemaciclib | 213 | 10.9 months | 0.59 (0.46–0.75) | <0.001 | link |
| Imlunestrant | 213 | 5.5 months | ||||
| Overall survival, ESR1-mutant (imlunestrant vs standard ET), updated | Imlunestrant | — | 34.5 months | — | — | link |
| Standard endocrine therapy | — | 23.1 months |
Replication
Monotherapy effect consistent with EMERALD and VERITAC-2; the combination result is the first randomised evidence for oral SERD + CDK4/6 after prior CDK4/6 exposure.