Phase III SOFIA study of MGAH 22 meets primary endpoint in breast cancer.- MacroGenics

MacroGenics announced positive results from SOPHIA, the Company�s Phase III clinical study of MGAH 22 (margetuximab) in HER2-positive metastatic breast cancer patients. Margetuximab is an investigational immune-enhancing monoclonal antibody derived from the Company�s proprietary Fc Optimization technology platform. The SOPHIA clinical trial met the primary endpoint of prolongation of progression-free survival (PFS) in patients treated with the combination of margetuximab plus chemotherapy compared to trastuzumab plus chemotherapy. Patients in the margetuximab arm experienced a 24% risk reduction in PFS compared to patients in the trastuzumab arm (HR=0.76, p=0.033). Notably, approximately 85% of patients in the study were carriers of the CD16A (FcyRIIIa) 158F allele, which has been previously associated with diminished clinical response to Herceptin and other antibodies.

In this pre-specified subpopulation, patients in the margetuximab arm experienced a 32% risk reduction in PFS compared to patients in the trastuzumab arm (HR=0.68, p=0.005). Results of the SOPHIA study are being prepared for submission for publication and presentation later this year at a major scientific conference. Follow-up for determination of the impact of therapy on the sequential primary endpoint of overall survival (OS) is ongoing, as pre-specified in the study protocol and recommended by the trial�s independent Data Safety Monitoring Committee. MacroGenics anticipates submitting a Biologics License Application (BLA) to the U.S. Food and Drug Administration in the second half of 2019.