Rezolute said its Phase 3 study of ersodetug in congenital hyperinsulinism missed the primary efficacy endpoint, prompting an immediate, severe market reaction and management to seek regulatory discussions. The trial did not separate ersodetug from placebo on average weekly hypoglycemia events; company statements said secondary endpoints failed to show statistical benefit as well. Investors drove shares down precipitously after the readout, with intraday moves nearing 80–90% in separate reports. Rezolute disclosed two serious hypersensitivity events that led to discontinuations and indicated it will meet the FDA to define next steps for the program. The failure imperils the company’s only late-stage asset and forces a strategic reassessment — including potential program termination, pivoting to alternate indications, or partnering — while undercutting expectations for a near-term approval and commercialization path.