Rezolute’s Phase 3 study in congenital hyperinsulinism did not meet endpoints

Rezolute (RZLT) announced topline results from its Phase 3 sunRIZE study evaluating ersodetug in patients with congenital hyperinsulinism, or HI. The study did not meet its primary endpoint, which assessed change in the average weekly hypoglycemia events by self monitored blood glucose. There was an approximate 45% reduction in hypoglycemia events observed at the top ersodetug dose, which was not statistically significant compared to the placebo group, which experienced a 40% improvement. Furthermore, the study did not meet its key secondary endpoint, which assessed change in average daily percent time in hypoglycemia. At the 10 mg/kg dose of ersodetug, an approximate 25% reduction in time in hypoglycemia was observed, which was not statistically significant compared to the placebo, which increased by approximately 5%. Safety observations from the study were generally favorable and, in the opinion of the company, support safe use of ersodetug in pediatric and adult patients. The incidence of serious allergic reactions across the program is relatively low compared to biologic or monoclonal antibody treatments. The most commonly reported study adverse event in ersodetug treated participants compared to placebo was hypertrichosis, which was generally mild and self-limiting. The Phase 3 upLIFT study for tumor HI is ongoing with topline results expected in the second half of 2026.