Regeneron today announced their plan to discontinue further development of suptavumab (REGN2222) after the investigational treatment did not meet its Phase 3 primary endpoint of preventing medically-attended respiratory syncytial virus (RSV) infections in infants.

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.

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The study also found that adverse events were generally balanced between suptavumab and placebo. “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, MD, PhD, President and Chief Scientific Officer of Regeneron. 

The Company stated that the full findings of the NURSERY trial will be presented at a future medical congress.

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