Top-line interim phase I/II data from Icosavax Inc.’s virus-like particle COVID-19 vaccine fell short of company and market expectations. IVX-411, which displays the SARS-CoV-2 receptor binding domain, was found to be immunogenic and well-tolerated, but the level of immune response was lower than anticipated and inconsistent with data on Icosavax’s platform and its preclinical results.