REDWOOD CITY, Calif., May 01, 2026
Rezolute, Inc. has announced detailed results from its Phase 3 sunRIZE study evaluating ersodetug, a monoclonal antibody therapy, in patients with congenital hyperinsulinism (HI), highlighting clinically meaningful improvements in glycemic control despite not meeting the primary endpoint. The findings, presented at the Pediatric Endocrine Society (PES) 2026 Annual Meeting, reinforce the therapy’s potential to address a critical unmet need in rare metabolic disorders, where persistent hypoglycemia can lead to severe neurological complications.
Consistent Glycemic Improvements Across Multiple Endpoints
The expanded analysis demonstrated robust and consistent improvements in glucose control, particularly across continuous glucose monitoring (CGM)-based metrics. Patients treated with ersodetug showed greater than 50% reductions in time spent in hypoglycemia, along with 50–80% reductions in hypoglycemic events compared to placebo across multiple timepoints. Additionally, there were significant increases in time spent in normoglycemia (70–180 mg/dL) and average blood glucose levels, indicating improved metabolic stability.
These outcomes were observed across both Full Analysis Set (FAS) and Per Protocol Set (PPS) populations, strengthening confidence in the drug’s biological activity and target engagement. While the trial’s primary endpoint—based on self-monitored blood glucose (SMBG)—did not achieve statistical significance, the company attributes this to methodological limitations and behavioral bias, rather than lack of efficacy, a position partially acknowledged in discussions with the U.S. FDA.
Sustained Benefits in Open-Label Extension Phase
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Beyond the randomized phase, the open-label extension (OLE) data further supports the durability of ersodetug’s effect. Notably, all 59 participants who completed the initial study phase opted to continue into the OLE, with 57 patients remaining actively engaged. Long-term observations indicate continued glycemic improvement over 6 to 24 months of treatment, alongside a significant reduction or discontinuation of standard-of-care therapies, including diazoxide and somatostatin analogs.
Importantly, many patients transitioned to ersodetug monotherapy, underscoring its potential to simplify treatment regimens and reduce dependency on existing therapies that often carry safety and tolerability concerns. These sustained benefits highlight the therapy’s real-world clinical relevance and long-term value proposition.
Regulatory Outlook and Clinical Significance
Rezolute has already engaged with the FDA through a Type B meeting, where the agency acknowledged the challenges associated with the primary endpoint design and requested submission of the complete dataset for comprehensive review. This interaction signals a constructive regulatory pathway, with the potential for alternative endpoints—particularly CGM-based outcomes—to play a critical role in future approval considerations.
Ersodetug’s mechanism of action, targeting insulin receptor overactivation downstream of pancreatic insulin secretion, positions it as a potentially universal therapy for multiple forms of hyperinsulinism, both congenital and acquired. Given the lack of effective and durable treatment options for HI patients, these findings represent a meaningful step toward transforming disease management.
In summary, despite missing its primary endpoint, the totality of evidence strongly supports ersodetug’s therapeutic potential, with consistent, clinically relevant glycemic improvements, durable long-term benefits, and a clear path toward regulatory engagement, positioning Rezolute at the forefront of innovation in rare endocrine disorders.
Source: Rezolute press release
