SERENA-6
The first trial to change treatment because of a blood test rather than a scan: switching to camizestrant when an ESR1 mutation appeared in the blood delayed progression by seven months.
3,256 patients screened by serial ctDNA; 315 with an emergent ESR1 mutation randomised. PFS 16.0 vs 9.2 months (HR 0.44, P<0.0001). OS immature; no crossover. FDA ODAC voted 6-3 against (30 April 2026), questioning the clinical meaning of acting on ctDNA before progression; the FDA nonetheless granted accelerated approval on 4 September 2026 (Etcamah), the first ctDNA-triggered switch indication.
- Median 16 vs 9.2 months with Switch to camizestrant + CDK4/6 compared with Continue AI + CDK4/6; about 6.8 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 56 percent lower chance of the event at any given time (hazard ratio 0.44, likely range 0.31 to 0.6).
- 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: First-line HR+/HER2- advanced breast cancer on AI + CDK4/6 with an ESR1 mutation detected in ctDNA before radiographic progression: switch to camizestrant + CDK4/6 vs continue AI + CDK4/6. 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.
315 participants enrolled.
| Endpoint | Arm | n | Value | HR (95% CI) | p | Source |
|---|---|---|---|---|---|---|
| Progression-free survivalprimary | Switch to camizestrant + CDK4/6 | 157 | 16 months | 0.44 (0.31–0.6) | <0.0001 | link |
| Continue AI + CDK4/6 | 158 | 9.2 months |
Pages like this
not linked directly; found by shared links- TrialEMERALD
Shares Selective oestrogen receptor degrader (SERD), ESR1 mutation, Estrogen receptor (ERα), HR-positive / HER2-negative breast cancer.
- IdeaA clone report from blood at every treatment cycle
Shares Molecular-progression switching beyond ESR1, Tumour heterogeneity and clonal evolution, Circulating tumour DNA (ctDNA), Acquired resistance to every therapy.
- ProductImlunestrant
Shares Oral SERD + CDK4/6 inhibitor after ESR1 emergence, ESR1 mutation, Estrogen receptor (ERα), HR-positive / HER2-negative breast cancer.
- TrialEMBER-3
Shares Oral SERD + CDK4/6 inhibitor after ESR1 emergence, ESR1 mutation, Estrogen receptor (ERα), HR-positive / HER2-negative breast cancer.
- IdeaLook for the resistant sub-population before the first dose
Shares Estrogen receptor (ERα), Tumour heterogeneity and clonal evolution, Acquired resistance to every therapy, Liquid biopsy (ctDNA).
- ProductElacestrant
Shares Selective oestrogen receptor degrader (SERD), ESR1 mutation, Estrogen receptor (ERα), Liquid biopsy (ctDNA).
- IdeactDNA-guided dose holidays for lung cancer targeted therapy
Shares Tumour heterogeneity and clonal evolution, Circulating tumour DNA (ctDNA), Acquired resistance to every therapy, Liquid biopsy (ctDNA).
- TermEndocrine resistance
Shares Selective oestrogen receptor degrader (SERD), Estrogen receptor (ERα), Acquired resistance to every therapy, HR-positive / HER2-negative breast cancer.