MacroGenics down on detailed OS data for margetuximab

After getting a bump in May on data released ahead of ASCO, MacroGenics lost $3.13 (17%) to $15.58 on Tuesday following detailed overall survival data from the Phase III SOPHIA trial of margetuximab to treat HER2-positive metastatic breast cancer. The company still plans to submit a BLA to FDA next half and an MAA to EMA next year for the Fc optimized mAb against HER2, said President and CEO Scott Koenig on a conference call to discuss the data.

On Tuesday at the American Society of Clinical Oncology meeting in Chicago, MacroGenics Inc. (NASDAQ:MGNX) reported that margetuximab plus chemotherapy led to a median OS of 18.9 months vs. 17.2 months for Herceptin trastuzumab plus chemotherapy (HR=0.95) in the intent-to-treat (ITT) population. In a prespecified subgroup of patients carrying the CD16a 158F allele, which accounted for about 86% of the study's 536 patients, median OS improved to 23.6 months in the margetuximab arm vs. 16.9 months in the Herceptin arm (HR=0.82)...