Switching to camizestrant at ESR1 mutation emergence before disease progression during first-line treatment of hormone receptor-positive advanced breast cancer (SERENA-6): extended analysis of a double-blind, placebo-controlled, randomised, phase 3 trial.

Switching to camizestrant at ESR1 mutation emergence during first-line therapy significantly extends progression-free survival in hormone receptor-positive advanced breast cancer, with a median of 16.8 months.

• Why it matters: Understanding how to overcome acquired resistance in hormone receptor-positive breast cancer is crucial for improving patient outcomes, as ESR1 mutations often lead to therapy failure.
• What they did: The phase 3 SERENA-6 trial monitored circulating tumour DNA in 548 patients, randomly assigning 315 with ESR1 mutations to switch to camizestrant plus CDK4/6 inhibitor or continue aromatase inhibitor plus CDK4/6 inhibitor, assessing progression-free survival.
• The result: Switching to camizestrant improved median progression-free survival by over 7 months and second progression-free survival by approximately 6 months, supporting targeted therapy upon ESR1 mutation detection to prolong treatment efficacy.