The Phase 3 sunRIZE study (RZ358-301) was a multi-center, randomized, double-blind, placebo-controlled, parallel arm study designed to evaluate the efficacy and safety of ersodetug in patients with congenital HI, ages 3 months to 45 years old, who were experiencing continued hypoglycemia on currently available standard of care (SOC). Eligible participants were randomized to one of three treatment arms to receive either ersodetug (5 or 10 mg/kg) or matched placebo-control as add on to existing SOC. Study drug was administered every other week during an initial loading phase, and then every 4 weeks during the 6-month controlled pivotal treatment period. The study was to enroll approximately 56 participants in more than a dozen countries around the world, inclusive of U.S. patients, which was completed and exceeded. Following the pivotal treatment phase of the study, participants had the option to roll-over into an optional open-label extension phase to continue to receive ersodetug. All 59 participants who completed the study elected to continue to receive ersodetug in the OLE. As of January 2026, 57 participants remain in the OLE, with an exposure duration ranging from ~6 weeks for the most recently entered patients, to ~18 months.

While sunRIZE did not meet its primary or key secondary endpoints, Rezolute believes that the totality of the data further supports previous clinical evidence that ersodetug is active against hypoglycemia in patients. The Company is currently engaging with FDA under Breakthrough Therapy Designation to determine next steps for the program.

For additional information about the trial, please visit clinicaltrials.gov using the identifier NCT06208215.

The Phase 3 registrational study is a single-arm, open-label, pivotal trial in approximately 16 participants with insulinoma or non-islet cell tumors who have uncontrolled hypoglycemia caused by tumor HI. Eligible participants requiring continuous intravenous (IV) glucose will receive ersodetug 9 mg/kg per week for 8 weeks, as an add-on to standard of care. Following this 8-week pivotal treatment period, all participants may receive ersodetug in long-term extension. The primary endpoint is the number of participants achieving at least a 50 percent reduction from baseline in IV glucose requirements (glucose infusion rate; GIR). Additional endpoints include the number of participants and time to discontinuation of GIR, time to discharge from the hospital, extent of hypoglycemia events and hypoglycemia time in the outpatient setting by self-monitored blood glucose and continuous glucose monitor, respectively, and patient reported quality of life.

For additional information about the trial, please visit clinicaltrials.gov using the identifier NCT06881992.