evERA: giredestrant plus everolimus beat standard endocrine therapy plus everolimus

Design

Phase 3, randomised, open-label

Population

373 patients with ER+, HER2− advanced breast cancer after a CDK4/6 inhibitor

Primary outcome

Investigator-assessed progression-free survival (ESR1-mutated, then overall)

Effect

ESR1-mutated 10.0 vs 5.5 months, HR 0.38 (95% CI 0.27–0.54); overall HR 0.56 (0.44–0.71)

evERA, published in NEJM on 1 October 2026, randomised 373 patients with ER-positive, HER2-negative advanced breast cancer that had progressed after a CDK4/6 inhibitor with endocrine therapy. They received the oral selective oestrogen receptor degrader giredestrant with everolimus, or the investigator's choice of exemestane, fulvestrant or tamoxifen with everolimus.

In the 207 patients with ESR1-mutated tumours, median progression-free survival was 10.0 months against 5.5 months (HR 0.38). In the whole population it was 8.8 against 5.5 months (HR 0.56). Toxicity was similar and dominated by everolimus: stomatitis in nearly half, then diarrhoea and anaemia.

The trial was open-label, progression was assessed by investigators, and overall survival data are immature. Benefit in ESR1 wild-type tumours appears smaller, and the overall result is driven largely by the mutated group. Giredestrant was investigational when the trial was published, and its regulatory status in India is not known. For patients with ESR1-mutated disease after a CDK4/6 inhibitor, an oral SERD-based combination is likely to become a preferred option once available.

• Test for ESR1 mutation on circulating tumour DNA at progression after a CDK4/6 inhibitor.
• Consider an oral SERD-based regimen, where available, for ESR1-mutated disease after a CDK4/6 inhibitor.
• Start dexamethasone mouthwash prophylaxis with everolimus to reduce stomatitis.
• Monitor glucose, lipids and for pneumonitis on everolimus-containing regimens.

Why it matters

It gives everolimus a more effective endocrine partner in the setting where resistance is usual.

Don't overread it

Overall survival is not yet known, and benefit is concentrated in ESR1-mutated tumours.

The statistics, in plain English

A hazard ratio of 0.38 means the risk of progression or death at any time was about 60% lower in ESR1-mutated patients. Progression-free survival is not overall survival, and open-label investigator assessment can favour the new treatment.

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