AstraZeneca said Phase III SERENA-4 missed its primary endpoint: camizestrant plus palbociclib did not significantly improve progression-free survival over anastrozole plus palbociclib in first-line ER-positive, HER2-negative advanced breast cancer.
AstraZeneca announced the result on September 11, 2026. The article says the combination produced a numerical improvement over the comparator and showed no new safety signals.
The article says SERENA-4 narrows camizestrant's potential as a broad first-line option, increasing the importance of biomarker-selected use. It cites positive SERENA-6 results in patients who develop ESR1 mutations during first-line therapy and ongoing Phase III CAMBRIA trials in early breast cancer as other opportunities.
