Rezolute to Present Results from its Phase 3 sunRIZE Study in Congenital Hyperinsulinism at the Pediatric Endocrine Society (PES) Annual Meeting

Oral presentation will include previously announced topline results as well as pre-specified and post-hoc data updates

REDWOOD CITY, Calif., April 21, 2026 — Rezolute, Inc. (Nasdaq: RZLT) (“Rezolute” or the “Company”), a late-stage rare disease company focused on treating hypoglycemia caused by all forms of hyperinsulinism (HI), today announced that results from the Phase 3 sunRIZE study of ersodetug in congenital HI were accepted for an oral presentation at the Pediatric Endocrine Society (PES) Annual Meeting being held April 30-May 3, 2026, in San Francisco, CA. In addition to the previously reported topline results, the presentation will also include results from pre-specified and post-hoc sunRIZE analyses, which the Company believes continue to demonstrate target engagement and the therapeutic benefit of ersodetug.

Presentation Title: Top-Line Results From a Global, Multicenter, Randomized, Double-Blind, Placebo-Controlled Phase 3 Study (sunRIZE) Format: Oral presentation Presenter: Diva D. De León-Crutchlow, MD, MSCE Session Date and Time: Friday, May 1, 2026, from 8:15 a.m. – 9:15 a.m. PT Session Title: Oral Abstracts #1

For more information on the conference presentation schedule, please visit the PES Annual Meeting website.

About sunRIZE

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 hyperinsulinism (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. Following the pivotal treatment phase of the study, participants could roll-over into an optional open-label extension phase to continue to receive ersodetug.

The study enrolled 63 participants in more than a dozen countries around the world, inclusive of U.S. patients. The primary and key secondary efficacy endpoints in the study were the change from baseline in the average number of hypoglycemia events per week and the average percent time in hypoglycemia, respectively, over six months of treatment.

About Ersodetug

Ersodetug is a fully human monoclonal antibody that binds allosterically to the insulin receptor to decrease receptor over-activation by insulin and related substances (such as IGF-2) in the setting of hyperinsulinism (HI), thereby improving hypoglycemia. Because ersodetug acts downstream from the pancreas, it has the potential to be universally effective at treating hypoglycemia due to any congenital or acquired form of HI.

About Rezolute, Inc.

Rezolute is a late-stage rare disease company focused on treating hypoglycemia caused by hyperinsulinism (HI). The Company’s antibody therapy, ersodetug, is designed to treat all forms of HI and has been studied in clinical trials and used in real-world cases for the treatment of both congenital and tumor HI. For more information, visit www.rezolutebio.com.