The Menarini Group and SciClone Pharmaceuticals (Holdings) Ltd. announced that they have entered into an exclusive sub-licensing agreement to develop and commercialize ORSERDU® (elacestrant) in the People?s Republic of China (China), in an effort to expand treatment options for appropriate metastatic breast cancer (mBC) patients. ORSERDU, a once-daily oral endocrine monotherapy, for the treatment of postmenopausal women or adult men, with ER+, HER2-, ESR1-mutated advanced or metastatic breast cancer with disease progression following at least one line of endocrine therapy, was approved by the U.S. Food and Drug Administration in January 2023 [1] under its priority review and fast track designation. In September 2023 [2], ORSERDU was approved by the European Commission.

Stemline Therapeutics, a wholly-owned subsidiary of the Menarini Group, focused on bringing transformational oncology treatments to cancer patients, commercializes ORSERDU in the U.S. and E.U. Under the Sub-Licensing agreement, SciClone will pursue the development and registration of ORSERDU in China and commercialize ORSERDU upon its regulatory approval in China. The approval of ORSERDU in the U.S. and E.U. is supported by data from the Phase 3 EMERALD trial, which demonstrated statistically significant progression-free survival (PFS) with elacestrant versus standard-of-care (SOC), defined as investigator?s choice of an approved endocrine monotherapy. The primary endpoints of the study were PFS in the overall patient population and in patients with ESR1 mutations.

In the group of patients whose tumors had ESR1 mutations, elacestrant achieved a median PFS of 3.8 months vs 1.9 months on the SOC, and reduced the risk of progression or death by 45% (PFS HR=0.55, 95% CI: 0.39, 0.77) vs SOC. A post hoc subgroup analysis of the EMERALD PFS results, which was presented at the San Antonio Breast Cancer Symposium (SABCS) 2022, demonstrated that the duration of prior CDK4/6i treatment was positively associated with longer PFS on elacestrant but not with SOC. For patients with ESR1 mutations who were treated with CDK4/6i for =12 months prior to randomization on EMERALD, elacestrant achieved a median PFS of 8.6 months versus 1.9 months on SOC, with a 59% reduction in the risk of progression or death (HR=0.41 95% CI: 0.26-0.63).