REDWOOD CITY, Calif. — October 5, 2026
Rezolute, Inc. announced that the U.S. FDA has recommended a Type B pre-BLA meeting following its preliminary review of detailed data from the Phase 3 sunRIZE study of ersodetug for congenital hyperinsulinism (HI). The FDA recommendation represents an important regulatory step toward a potential Biologics License Application (BLA) for the investigational therapy, although the agency did not determine whether ersodetug is approvable. The recommendation follows Rezolute’s submission of continuous glucose monitoring (CGM) data and analyses addressing challenges encountered in the sunRIZE trial. Rezolute is also preparing to report topline results from its Phase 3 upLIFT study in tumor-related hyperinsulinism during the fourth quarter of 2026, which could influence the company’s broader regulatory strategy for ersodetug across different forms of HI.
FDA Reviews SunRIZE Data Despite Missed Endpoints
The Phase 3 sunRIZE study demonstrated improvements in glycemic control but did not meet its prespecified primary endpoint, as reductions in hypoglycemia events measured through finger-stick self-monitored blood glucose were not statistically significant compared with placebo. The key secondary endpoint evaluating time spent in hypoglycemia through CGM during the Week 24 end-of-treatment window also was not met. However, Rezolute reported consistent and clinically relevant improvements across multiple CGM-based hypoglycemia measures in both treatment arms. At a March 2026 Type B meeting, the FDA acknowledged behavioral factors and limitations associated with SMBG-based assessments in this patient population and requested that Rezolute provide CGM data for independent review. The company subsequently submitted source and analysis datasets, summary results and multiple prespecified, post-hoc and sensitivity analyses in June. Following its preliminary review, the FDA encouraged Rezolute to request a pre-BLA meeting, while explicitly stating that it had not made a determination regarding the potential approvability of ersodetug.
Ersodetug Targets Insulin Receptor Signaling
Ersodetug is a fully human monoclonal antibody designed to reduce excessive insulin receptor activation, with the goal of improving hypoglycemia associated with hyperinsulinism. The therapy binds allosterically to the insulin receptor and is intended to act downstream of excessive pancreatic insulin secretion or paraneoplastic IGF-2 signaling. This mechanism could potentially allow ersodetug to address refractory hypoglycemia across several forms of HI, including congenital HI, tumor-related HI and hypoglycemia following gastrointestinal surgery. Rezolute said the open-label extension of the sunRIZE study remains ongoing, with patients receiving ersodetug for approximately nine months to more than two years. Continued glycemic control and a notable reduction in background standard-of-care therapies were observed during longer-term treatment, although ersodetug remains investigational and its safety and efficacy have not been approved by regulatory authorities.
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Rezolute Prepares for Potential BLA Strategy
The recommended pre-BLA meeting gives Rezolute an opportunity to discuss the regulatory pathway for ersodetug in congenital HI despite the sunRIZE trial’s missed prespecified endpoints. The company expects to use discussions with the FDA to better understand the data package and requirements that would support a potential BLA submission. At the same time, Rezolute expects topline results from the Phase 3 upLIFT study in tumor HI later in 2026. If those results support a regulatory submission, the company may seek an additional pre-BLA meeting for the tumor HI indication. Rezolute plans to evaluate its overall BLA strategy after the upLIFT results become available, potentially considering regulatory submissions for both programs. The FDA recommendation therefore advances regulatory discussions for ersodetug while leaving the ultimate approval decision dependent on a formal review of the complete clinical and supporting data.
Source: Rezolute press release
