Fifty-seven out of 59 sunRIZE completers remain active in the open-label extension — a retention figure that is essentially unheard of in a rare pediatric disease trial, and it matters enormously to how the FDA will interpret a dataset that technically missed its prespecified finish line. Ersodetug’s primary endpoint, hypoglycemia event frequency by finger-stick SMBG, did not achieve statistical significance. What the expanded PES presentation makes clear is that the fingerstick-based measure was the wrong ruler for this drug in this population.
The CGM data tell a different story with consistency that is difficult to dismiss. Across the full analysis set, ersodetug reduced time in hypoglycemia by more than 50% versus placebo at multiple maintenance-phase timepoints; in the per-protocol set, that figure stretches to 60–80%. Weekly hypoglycemic event counts fell 50–80% in the per-protocol population. Normoglycemic exposure — time between 70 and 180 mg/dL — rose 25–50%. These are not marginal signals scattered across one or two post-hoc slices; they appear repeatedly across prespecified and exploratory CGM endpoints alike, which is exactly the kind of structural consistency that distinguishes biological effect from noise. The FDA acknowledged as much in a March 2026 Type B meeting, conceding that the finger-stick primary endpoint created interpretive problems and requesting the full dataset for comprehensive review rather than issuing a clean rejection.
The OLE data add a layer that no randomized trial can generate on its own. Patients who crossed over from placebo showed clinically significant glycemic improvement after starting ersodetug, functioning as an internal replication. More practically, enough patients have reduced or eliminated background standard-of-care therapies — diazoxide, somatostatin analogs, tube feeds — that a meaningful subset is now on ersodetug monotherapy. That shift is not cosmetic. It represents a real-world signal that the drug is carrying sufficient glycemic load to displace treatments families have depended on for years.
The single consequence to track now is what data package Rezolute submits to FDA and whether the agency accepts a CGM-based efficacy narrative as the evidentiary backbone of an NDA — a precedent that would reshape endpoint selection for every future hyperinsulinism trial.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
