HilleVax, Inc. announced topline data results from NEST-IN1. NEST-IN1 is a Phase 2b, randomized, double-blind, placebo-controlled clinical trial to evaluate the efficacy, safety, and immunogenicity of HIL-214 in infants of approximately 5 months of age at the time of initial vaccination at sites in the United States and Latin America. In the NEST-IN1 study there were 51 primary endpoint events with 25 in the vaccine arm (n=1,425) and 26 in the placebo arm (n=1,399) resulting in vaccine efficacy of 5% (95% confidence interval; -64%, 45%).

The study did not meet its primary endpoint of efficacy against moderate or severe acute gastroenteritis (AGE) events due to GI.1 or GII.4 norovirus genotypes. No clinical benefit was observed across secondary endpoints. HIL-214 exhibited a safety and immunogenicity profile consistent with what was observed in the prespecified analysis of the first 200 subjects in NEST-IN1 and in previously reported studies.

The NEST-IN1 study was conducted after a Phase 2b study in adults, NOR-211, demonstrated statistically significant efficacy against moderate or severe AGE due to norovirus. The company plans to discontinue further development of HIL-214 in infants and is exploring the potential for continued development of HIL-214 and HIL-216, HilleVax?s Phase 1 ready vaccine candidate, in adults.