AstraZeneca’s oral SERD, Etcamah, in combination with a CDK 4/6 inhibitor, did not meet the primary endpoint of progression-free survival in a phase 3 trial of patients with ER-positive, HER2-negative advanced breast cancer.
The SERENA-4 phase 3 trial evaluated Etcamah in combination with palbociclib versus treatment with an aromatase inhibitor (anastrozole) in combination with palbociclib. While the treatment failed to meet the trial’s primary endpoint, AstraZeneca said a numerical improvement was observed in the upfront 1st-line treatment of patients with ER-positive, HER2-negative advanced breast cancer who have not received any systemic treatment for advanced disease.
The news comes a week after the FDA granted accelerated approval to Etcamah, allowing the drug to be used in combination with a CDK4/6 inhibitor for patients already on first-line aromatase inhibitor therapy who develop an emergent ESR1 mutation detected by a blood test, letting them switch to camizestrant before their disease clinically progresses. This indication is different from what was tested in the SERENA-4 trial, which tried to use camizestrant plus palbociclib as an entirely new frontline regimen for previously untreated metastatic patients.