AstraZeneca’s oral SERD camizestrant (Etcamah) missed key efficacy in a Phase 3 study designed to expand its breast cancer use into a first-line setting. In the Serena-4 trial, Etcamah plus palbociclib did not meet the primary endpoint of progression-free survival in first-line HER2-negative, estrogen receptor-positive disease. The latest results follow a recent accelerated approval in an enriched population framework based on ESR1 mutation detection, reinforcing that oral SERDs may still face a performance ceiling outside biomarker-selected groups. Analysts noted the readout aligns with prior concerns after Roche’s giredestrant also failed in a similar setting. AstraZeneca is now focusing on additional development decisions, including other trials such as AVANZAR in first-line non-small-cell lung cancer, while recalibrating expectations for Etcamah’s label potential in breast cancer.