Regeneron will discontinue development of suptavumab (REGN2222) after the investigational drug failed to meet prevent respiratory syncytial virus (RSV) infections in infants during a Phase 3 trial.

The trial entitled NURSERY, enrolled 1,149 healthy pre-term infants with a gestational age of ?36 months and who were ?6 months at the start of the trial. They were randomized 1:1:1 to either suptavumab 30mg/kg as a single dose; suptavumab 30mg/kg as two doses 8 weeks apart; or placebo.

The primary endpoint of RSV prevention – assessed through day 150 of treatment – was not significantly reached.