Rezolute, Inc. (NASDAQ:RZLT) saw its stock plunge 90% on Thursday after revealing that its Phase 3 sunRIZE trial of ersodetug in congenital hyperinsulinism (HI) patients failed to achieve its primary endpoint or its key secondary objectives.
According to the company, the study recorded roughly a 45% reduction in hypoglycemia events at the highest dose tested (10 mg/kg). However, this was not statistically meaningful when compared with the placebo group, which posted a 40% improvement. The secondary measure—change in average daily percent time in hypoglycemia using continuous glucose monitoring—also fell short. Patients on the 10 mg/kg dose saw a 25% reduction, while placebo patients experienced a 5% increase, yet the difference again did not reach statistical significance.
“We are disappointed that the study did not demonstrate significant improvements in glucose-related endpoints relative to placebo as well as for the patients and families living with congenital HI who urgently need new treatment options,” said Brian Roberts, M.D., Chief Medical Officer of Rezolute.
Rezolute indicated that overall safety findings were largely acceptable, though two participants experienced serious hypersensitivity reactions that resulted in early withdrawal from the trial. The most commonly reported side effect among treated patients was mild, self-limiting hypertrichosis.
The company said it intends to meet with the FDA under its Breakthrough Therapy Designation to determine potential next steps for the ersodetug program. Rezolute’s separate Phase 3 upLIFT study in tumor hyperinsulinism remains underway, with top-line results anticipated in the second half of 2026.