Regeneron Pharmaceuticals, Inc. will discontinue development Suptavumab after a Phase III study evaluating suptavumab (REGN2222), an Antibody to respiratory syncytial virus (RSV), did not meet its primary Endpoint of preventing medically-attended RSV infections in infants. Suptavumab did show signs of Efficacy in a subgroup of patients. Adverse events were generally balanced between suptavumab and Placebo . Regeneron plans to discontinue further clinical development of this antibody. 

"We are disappointed in these results, as we had hoped suptavumab might offer a new option for the thousands of infants impacted by serious RSV infections every year," said George D. Yancopoulos, M.D., Ph.D., president and chief scientific officer of Regeneron. "Regeneron has a robust pipeline across many serious diseases, and we look forward to important data readouts from other programs in the coming weeks and months."

The double-blind, placebo-controlled Phase III study enrolled 1,149 healthy pre-term infants. Patients were randomized to one of three study groups: suptavumab 30 mg/kg as a single dose; suptavumab 30 mg/kg administered as two doses 8 weeks apart; or placebo. Patients were considered 'medically-attended' if they required hospitalization and/or sought medical care for a centrally-adjudicated RSV infection. Pre-term infants in the study had a gestational age of less than 36 weeks and were 6 months old or younger at the beginning of the study.