Rezolute's Topline Data From Its Phase 3 sunRIZE Study Evaluating Ersodetug In Patients With Congenital Hyperinsulinism Did Not Meet The Primary Or Key Secondary Endpoint

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 (10 mg/kg), 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 by continuous glucose monitoring (CGM). 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%.

At the study dose regimens of 5 and 10 mg/kg administered every other week for 3 doses, followed by every 4 weeks over the remainder of the 24-week treatment duration, ersodetug target drug concentrations were achieved, across all age groups studied.

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. Two of the study participants experienced serious hypersensitivity reactions which led to early discontinuation of study drug. 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.

"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. "At the same time, there are aspects of the results that merit additional investigation, and we are conducting a thorough evaluation to gain a better understanding of the study outcomes, which will inform our path forward. We intend to meet with FDA under our Breakthrough Therapy Designation to consider next steps for the program. We are deeply grateful to the patients and families, the majority of whom have continued into the open label extension part of the study, as well as to the investigators and site teams who participated in this important study."

The Phase 3 upLIFT study for tumor HI is ongoing with topline results expected in the second half of 2026.