REDWOOD CITY, Calif. — September 9, 2026
Rezolute, Inc. provided an update on the U.S. Food and Drug Administration’s ongoing review of data from the Phase 3 sunRIZE study of ersodetug for hypoglycemia caused by congenital hyperinsulinism (HI). The Phase 3 study demonstrated reductions in hypoglycemia events from baseline but did not meet its primary endpoint because the reductions were not statistically significant compared with placebo. Following a March 2026 Type B meeting, the FDA requested additional study data for independent review, and Rezolute submitted source and analysis datasets and summary results in June, including extensive pre-specified, post-hoc and sensitivity analyses focused on continuous glucose monitoring (CGM)-based outcomes. The company said the submitted data include potential evidence of target engagement, pharmacologic activity and glycemic improvement, while the FDA has reiterated that its review remains ongoing.
FDA Reviews Additional CGM-Based Glycemic Data
Rezolute’s regulatory strategy now centers on the additional CGM analyses submitted to the FDA, following concerns about behavioral factors and limitations associated with self-monitored blood glucose measures in the congenital HI population. According to the company, consistent improvements compared with placebo were observed across multiple CGM-based outcomes at both ersodetug dose levels. These included 50% or greater reductions in average daily percentage of time spent in hypoglycemia and average weekly hypoglycemia events. Rezolute said larger and often nominally statistically significant improvements were also observed during the maintenance dosing period across multiple pre-specified and post-hoc CGM endpoints, although the study did not achieve statistical significance for its primary or key secondary endpoints at the Week 24 evaluation. The FDA is evaluating the broader dataset to determine whether there may be a potential regulatory path forward for ersodetug in congenital HI.
sunRIZE Extension Continues Long-Term Ersodetug Evaluation
The open-label extension phase of sunRIZE remains ongoing with a high participation and retention rate, providing Rezolute with additional longer-term treatment information while the FDA conducts its review. Cumulative ersodetug exposure among participants now ranges from approximately nine months to more than two years, accompanied by continued glycemic monitoring. The company also highlighted a notable reduction in participants’ use of background standard-of-care therapies during the extension period, which it views as a potential indicator of sustained glycemic and clinical benefit. The sunRIZE study enrolled 63 participants across more than a dozen countries, including patients from the United States, aged three months to 45 years who continued to experience hypoglycemia despite available standard-of-care treatment. Rezolute will continue working with the FDA while retaining the option to request a formal regulatory meeting if needed to establish a clearer development pathway.
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Rezolute Advances Broader Ersodetug Development Strategy
Rezolute continues to advance ersodetug beyond congenital HI through the Phase 3 upLIFT study in tumor hyperinsulinism, with topline results expected before the end of 2026. Ersodetug is a fully human monoclonal antibody designed to bind allosterically to the insulin receptor and reduce receptor overactivation by insulin and related substances such as IGF-2. Its downstream mechanism is intended to address refractory hypoglycemia associated with different forms of hyperinsulinism, including congenital HI, insulinoma and other tumor-related HI, as well as post-surgical hypoglycemia. While the regulatory pathway for congenital HI remains dependent on the FDA’s ongoing review, the sunRIZE extension, additional regulatory analyses and the advancing upLIFT program provide Rezolute with multiple clinical and development milestones for its broader ultra-rare disease strategy.
Source: Rezolute, ,press release
