Camizestrant Switch Halves Progression Risk in Emerging ESR1-Mutant HR+/HER2- mBC

Camizestrant, a next-generation oral selective estrogen-receptor degrader, was tested in the phase 3 SERENA-6 trial (NCT04964934). 315 ER-positive/HER2-negative metastatic breast cancer patients who developed an ESR1 mutation on first-line aromatase-inhibitor (AI) + CDK4/6 therapy (with no radiologic progression) were randomized to swap the AI for camizestrant (75 mg daily) while continuing the CDK4/6 inhibitor (n = 157) or to stay on the AI (n = 158). Median PFS reached 16.0 mo vs 9.2 mo (HR 0.44; p<0.0001); time to patient-reported QoL decline stretched 23.0 vs 6.4 mo, and discontinuations for adverse events were similarly low (1.3% vs 1.9%).