MacroGenics dosed the first patient in a Phase I dose expansion cohort trial of MGA271, triggering a $10 million milestone payment from its partner, Servier. MGA271 is an Fc-optimized monoclonal antibody that targets B7-H3, which is overexpressed on a variety of solid tumor types.
The dose expansion portion of this study is designed to further evaluate safety and pharmacokinetics at a weekly dose of 15 mg/kg. It includes an early evaluation of the potential antitumor activity of MGA271. Twenty-six patients were enrolled—representing 15 different types of tumors—and 10 patients received additional cycles of MGA271 treatment. All patients had stable disease at the first tumor reassessment, according to the company. MacroGenics plans to enroll 45 patients within three cohort groups: two with specific tumor types of 15 patients each and a third cohort composed of other B7-H3-expressing tumor types.
MacroGenics expects to complete the trial in 2014. Servier intends to evaluate MGA271 in 45 additional cancer patients representing additional tumor types, beginning in the fourth quarter of 2013.
This milestone payment was received as part of an alliance formed in Sept. 2012 between the two firms to develop and commercialize three bispecific antibodies based on the former firm’s DART™ (dual-affinity retargeting) platform. MacroGenics received a $20 million upfront payment.