FDA approves Orserdu for ER+ HER2- ESR1-mutated breast cancer

Stemline Therapeutics, a wholly-owned subsidiary of the Menarini Group, headquartered in New York and focused on bringing transformational oncology treatments for cancer patients, will commercialize Orserdu in the U.S.

Orserdu is approved under the FDA’s Priority Review and Fast Track designation based on the results of the registrational Phase III trial EMERALD, that demonstrated statistically significant progression-free survival (PFS) with elacestrant vs SOC endocrine monotherapy (fulvestrant, letrozole, anastrozole, exemestane), meeting both primary endpoints in all patients and in those patients whose tumors harbor ESR1 mutations.

In the group of patients whose tumors had ESR1 mutations, elacestrant reduced the risk of progression or death by 45% (PFS HR=0.55, 95% CI: 0.39, 0.77) vs SOC. A post-hoc analysis of the PFS results based on the duration of prior CDK4/6i inhibitors (CDK4/6i) usage was presented at San Antonio Breast Cancer Symposium (SABCS) in December 2022. The median PFS was 8.6 months on elacestrant vs 1.9 months for SOC, in those patients whose tumors harbored ESR1 mutations and had been treated with a CDK4/6i for at least 12 months.

Safety data is consistent with the other endocrine therapies. Most of the adverse events (AEs), including nausea and musculoskeletal pain were grade 1 and 2. No hematological safety signal was observed and none of the patients in either of the two treatment arms had sinus bradycardia.