Rezolute Provides Insights from its Phase 3 sunRIZE Study in Congenital Hyperinsulinism and Shares Findings from its Expanded Access Program in Tumor Hyperinsulinism

Rhea-AI Summary

Rezolute (Nasdaq: RZLT) reported Phase 3 sunRIZE results in congenital hyperinsulinism and shared Expanded Access Program (EAP) outcomes in tumor HI on Jan 7, 2026.

The company said sunRIZE did not meet its primary or key secondary endpoints but observed pharmacologic activity: target therapeutic concentrations in 5 mg/kg and 10 mg/kg arms and sensitive biomarker increases in circulating insulin. All 59 completers entered an open-label extension (OLE); 57 remain with exposures ~6 weeks to ~18 months.

In the EAP, 75% of patients on IV dextrose/TPN discontinued infusions. Rezolute plans FDA discussions in Q1 2026 and expects upLIFT topline results in H2 2026.

Positive

• Target drug levels achieved in 5 mg/kg and 10 mg/kg groups
• Biomarker responses showed increased circulating insulin indicative of activity
• All 59 sunRIZE completers entered the open-label extension
• 57 participants remain in OLE with up to ~18 months exposure
• 75% of EAP patients on IV dextrose/TPN discontinued infusions

Negative

• sunRIZE failed primary endpoint (hypoglycemia events)
• Key secondary endpoint (time in hypoglycemia) also not met
• Reductions vs placebo were not statistically significant
• Pronounced placebo/study effect complicated ambulatory endpoints
• upLIFT topline results delayed until H2 2026

Key Figures

Ersodetug dose 5 mg/kg Active treatment group in Phase 3 sunRIZE congenital HI study

Ersodetug dose 10 mg/kg Higher-dose treatment group in Phase 3 sunRIZE congenital HI study

OLE participants 59 patients All 59 sunRIZE completers elected to enter open-label extension

OLE ongoing 57 patients Participants remaining in open-label extension at data cut

Exposure range ~6 weeks to ~18 months Ersodetug exposure duration in congenital HI open-label extension

EAP cohort size 9 participants Initial tumor HI Expanded Access Program cohort summarized in 8-K table

IV dextrose/TPN discontinuation 75% Tumor HI EAP patients on IV dextrose/TPN achieving complete discontinuation

upLIFT primary endpoint 50% GIR reduction; 9 of ~16 Participants needing ≥50% GIR reduction for statistical significance in Phase 3 upLIFT

Market Reality Check

$2.63 Last Close

Volume Volume 4,835,049 vs 20-day average 15,526,699 suggests trading was lighter than recent norms ahead of this update. low

Technical Price $1.91 is trading below the $5.92 200-day moving average, reflecting a weakened longer-term trend before this release.

Peers on Argus

RZLT was down 2.8% while close biotech peers were mixed: RIGL +4.29%, RLAY +4.48%, VIR +3.03%, KALV -1.33%, TBPH -0.22%. This points to stock-specific dynamics rather than a broad sector move.

Historical Context

Date	Event	Sentiment	Move	Catalyst
Dec 11	Phase 3 topline	Negative	-87.2%	sunRIZE failed primary and key secondary endpoints in congenital HI.
Nov 10	Equity inducement	Neutral	-7.5%	Inducement stock options granted under Nasdaq Listing Rule 5635(c)(4).
Nov 06	Earnings update	Positive	+2.7%	Reported Q1 FY26 results and confirmed timelines for sunRIZE and upLIFT.
Nov 05	Investor event	Positive	+5.1%	Announced virtual event to review ersodetug Phase 3 programs and markets.
Oct 15	Conference participation	Neutral	+6.9%	Planned appearances at multiple late-2025 healthcare investor conferences.

Pattern Detected

Clinical trial news has driven large moves, including a sharp selloff after the initial sunRIZE miss, while corporate and conference updates have produced smaller, mixed reactions.

Recent Company History

Over the past nine months, Rezolute has progressed ersodetug through key Phase 3 milestones in congenital and tumor hyperinsulinism. The company moved from interim DMC support and full enrollment in sunRIZE to baseline data disclosure and FDA alignment on using sunRIZE as confirmatory evidence. The December 2025 topline sunRIZE miss triggered a steep -87.2% reaction. Today’s announcement reframes those results with detailed pharmacologic insights and expanded access outcomes in tumor HI, tying directly back to prior clinical communications.

Market Pulse Summary

The stock surged +23.0% in the session following this news. A strong positive reaction aligns with how prior clinical milestones sometimes produced substantial moves, as seen with earlier sunRIZE and upLIFT updates. Investors previously repriced the stock sharply after the initial sunRIZE miss, so any renewed optimism could reflect perceived value in pharmacologic activity and tumor HI EAP outcomes. However, the failed primary and key secondary endpoints, reliance on open-label and EAP data, and the need for statistically robust upLIFT results in ~16 patients could limit sustainability.

Key Terms

phase 3 medical

"shared observations from the Phase 3 sunRIZE study in patients with congenital HI"

Phase 3 is the late-stage clinical testing step for a new drug or medical treatment, where the product is given to large groups of patients to confirm effectiveness, monitor side effects, and compare it to standard care. Successful Phase 3 results are often the final scientific hurdle before regulators decide on approval and market launch—like passing a final exam before graduation—and can sharply change a company's valuation and future revenue prospects.

expanded access program regulatory

"treatment of tumor HI patients with ersodetug under the Company’s EAP"

A program that allows patients with serious or life‑threatening conditions to receive an experimental drug or therapy before it is fully approved by regulators, when they cannot join clinical trials. Investors care because expanded access can change a treatment’s market perception, create early real‑world safety or demand signals, and affect regulatory timelines and potential revenue — like a pre‑order system that also reveals how the product performs outside controlled testing.

biomarker medical

"with highly sensitive biomarker responses (increases in circulating insulin)"

A biomarker is a measurable indicator found in the body, such as in blood or tissues, that provides information about health, disease, or how the body responds to treatment. For investors, biomarkers can signal the potential success or risk of medical products or therapies, influencing the value of related companies and industry trends. They act like signals or clues that help assess the progress of medical advancements and their market impact.

open-label extension medical

"assessing the potential benefit in the ongoing open-label extension (OLE) portion of the study"

An open-label extension is a continuation of a clinical trial where all participants and researchers know which treatment is being given, often after an initial blinded phase. It allows further study of a drug's long-term safety and effectiveness. For investors, it can indicate ongoing interest and confidence in a product's potential, influencing perceptions of its future value.

breakthrough therapy designation regulatory

"interacting with FDA in Q1 2026 under its Breakthrough Therapy Designation"

A breakthrough therapy designation is a regulatory fast-track given to a drug or treatment that shows early signs of providing a major improvement over existing options for a serious condition. Think of it as a VIP lane that can speed up development and more intensive guidance from regulators, which matters to investors because it can shorten time to market, reduce development risk and potentially increase a company’s value — though it does not guarantee approval.

insulinomas medical

"including malignant pancreatic neuroendocrine tumors (insulinomas) and non-islet cell tumors"

Insulinomas are rare tumors that form in the pancreas and produce excess insulin, causing low blood sugar episodes that can be dangerous if untreated. For investors, they matter because developing tests, drugs, or surgeries to detect or treat these tumors can drive clinical trial activity, regulatory milestones, and potential market value for medical companies the same way a new product for a common disease would — think of a niche but high-impact problem where a successful solution can command premium pricing and attention.

total parental nutrition (tpn) medical

"IV dextrose/total parental nutrition (TPN) in the EAP achieved a complete discontinuation"

Total parenteral nutrition (TPN) is a medical therapy that supplies all essential nutrients—calories, protein, fluids, electrolytes and vitamins—directly into the bloodstream through an intravenous line when a patient cannot eat or absorb food normally. For investors, TPN matters because it represents a steady demand stream for specialized nutrition formulas, infusion pumps, IV supplies and pharmacy services, and changes in use, reimbursement or clinical guidelines can affect hospitals, suppliers and healthcare margins.

glucose infusion rate medical

"reduction in the rate of glucose infusion in the hospital (GIR)"

Glucose infusion rate is the speed at which sugar is delivered into the bloodstream through an IV, usually adjusted for body size and expressed as a rate. Think of it as how fast fuel is poured into an engine: too little or too much can change how the body and drugs behave. Investors should care because this rate affects safety, metabolic responses and trial results for treatments or devices that influence blood sugar, which can change regulatory outcomes and market value.

AI-generated analysis. Not financial advice.

Company believes that data from sunRIZE and the Expanded Access Program (EAP) provide evidence of activity of ersodetug in both indications

Company plans to meet with FDA to align on path forward for congenital HI

REDWOOD CITY, Calif., Jan. 07, 2026 (GLOBE NEWSWIRE) -- 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 shared observations from the Phase 3 sunRIZE study in patients with congenital HI and provided details on the treatment of tumor HI patients with ersodetug under the Company’s EAP.

Congenital HI

While sunRIZE did not meet its primary (hypoglycemia events) or key secondary (time in hypoglycemia) endpoints, the Company believes that the totality of the data further supports previous clinical evidence that ersodetug is active against hypoglycemia in patients. Specifically, there was evidence of pharmacologic activity as target therapeutic drug concentrations were achieved in both treatment groups (5 mg/kg and 10 mg/kg) with highly sensitive biomarker responses (increases in circulating insulin) in the active treatment groups that are indicative of reduced insulin activity at its receptor. Notably, these responses were consistent with those of the Company’s Phase 2 RIZE study (see Figure 1).

The study also demonstrated reductions from baseline in events and time in hypoglycemia in both treatment groups, but not enough to be statistically significant compared to the pronounced study effect in the placebo arm. While in the early stages of evaluating study data and understanding the results, learnings in the field of glycemic control and initial observations from sunRIZE inform the Company’s belief that the pharmacologic response can translate to clinical efficacy. The magnitude of the placebo response observed for hypoglycemia events reveals a significant challenge in studying glucose in an ambulatory setting, where factors such as intensive monitoring where caregivers receive alerts regarding hypoglycemic events and frequent clinical interactions can independently influence outcomes.   

The Company believes that the extent of reduction from baseline in hypoglycemia events and time in hypoglycemia relative to placebo (see Figure 2) may have been impacted by the prolonged treatment duration of six months and the fact that glucose monitoring is necessary for safe patient management while also serving as the key endpoint in the study. This sentiment has been shared with the Company by investigator physicians as well as study participants. The Company is currently exploring how to characterize the overall study dynamic including evaluating patient-reported quality of life outcomes.

In light of these limitations, assessing the potential benefit in the ongoing open-label extension (OLE) portion of the study will be important. All 59 participants who completed the study elected to continue to receive ersodetug in the OLE. To date, 57 participants remain in the OLE, with an exposure duration ranging from ~6 weeks for the most recently entered patients, to ~18 months. The Company believes that a potential indicator of ersodetug’s underlying efficacy is that several children in the OLE have been able to stop taking all other therapies and are now receiving ersodetug as monotherapy. 

The Company looks forward to interacting with FDA in Q1 2026 under its Breakthrough Therapy Designation to further characterize these and other clinical outcomes to inform a review of the full sunRIZE dataset with the intent of exploring options for this indication.

Tumor HI

Over the past two years, Rezolute has collaborated with investigators across the United States and in Europe to provide ersodetug to more than a dozen patients with severe and refractory hypoglycemia due to tumor HI, including malignant pancreatic neuroendocrine tumors (insulinomas) and non-islet cell tumors. The Company has previously reported that the therapy was generally well-tolerated, and that patients experienced substantial improvement in hypoglycemia, which led to a reduction in the rate of glucose infusion in the hospital (GIR) or the complete discontinuation of infusion and discharge from the hospital.  

Presented in a table filed today on Form 8-K with the U.S. Securities and Exchange Commission are cumulative data from the initial 9 participants in the EAP, including patient characteristics, ersodetug dosing, and observed outcomes. This same data cohort was provided to FDA last year in support of the Company’s request for Breakthrough Therapy Designation and subsequently informed the discussion with FDA that led to revision of the Phase 3 upLIFT study in tumor HI to a single arm, open-label study. In summary, 75% of the patients receiving IV dextrose/total parental nutrition (TPN) in the EAP achieved a complete discontinuation of IV dextrose/TPN. 

This outcome is highly relevant to the ongoing upLIFT study and provides additional evidence of the activity and potential efficacy of ersodetug across various forms of HI. Notably, the GIR assessment in the EAP is the primary endpoint in upLIFT, which measures the number of participants (out of ~16) who achieve at least a 50% reduction in GIR, an objective endpoint in a highly controlled hospital setting. For statistical significance, 9 of 16 open-label participants need to achieve this threshold. Topline results are anticipated in the second half of 2026.

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.

Forward-Looking Statements

This release, like many written and oral communications presented by Rezolute and our authorized officers, may contain certain forward-looking statements regarding our prospective performance and strategies within the meaning of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended. We intend such forward-looking statements to be covered by the safe harbor provisions for forward-looking statements contained in the Private Securities Litigation Reform Act of 1995 and are including this statement for purposes of said safe harbor provisions. Forward-looking statements, which are based on certain assumptions and describe future plans, strategies, and expectations of Rezolute, are generally identified by use of words such as "anticipate," "believe," "estimate," "expect," "intend," "plan," "project," "seek," "strive," "try," or future or conditional verbs such as "could," "may," "should," "will," "would," or similar expressions. These forward-looking statements include, but are not limited to, the potential efficacy of ersodetug in treating hypoglycemia associated with either congenital or tumor HI, the possibility of FDA agreeing to a streamlined path for advancing the congenital HI program notwithstanding the lack of statistical significance in the sunRIZE study,  or the timing of the release of topline results for upLIFT. Our ability to predict results or the actual effects of our plans or strategies is inherently uncertain. Accordingly, actual results may differ materially from anticipated results. Readers are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this release. Except as required by applicable law or regulation, Rezolute undertakes no obligation to update these forward-looking statements to reflect events or circumstances that occur after the date on which such statements were made. Important factors that may cause such a difference include any other factors discussed in our filings with the SEC, including the Risk Factors contained in Rezolute’s Annual Report on Form 10-K and Quarterly Reports on Form 10-Q, which are available at the U.S. Securities and Exchange Commission’s website at www.sec.gov. You are urged to consider these factors carefully in evaluating the forward-looking statements in this release and are cautioned not to place undue reliance on such forward-looking statements, which are qualified in their entirety by this cautionary statement.

Rezolute Contacts:

Christen Baglaneas
cbaglaneas@rezolutebio.com
508-272-6717

Carrie McKim
cmckim@rezolutebio.com
336-608-9706

Figures accompanying this announcement are available at:

https://www.globenewswire.com/NewsRoom/AttachmentNg/29e42211-3bf5-4995-a1c1-9642d5f28ab4

https://www.globenewswire.com/NewsRoom/AttachmentNg/9bdb41c4-5a9f-4da2-894e-2bf0b1ca7b40

FAQ

What were the sunRIZE Phase 3 results for Rezolute (RZLT) announced Jan 7, 2026?

sunRIZE did not meet its primary (hypoglycemia events) or key secondary (time in hypoglycemia) endpoints, though pharmacologic activity was observed.

How many participants continued into the sunRIZE open-label extension for RZLT?

All 59 participants who completed sunRIZE elected to continue; 57 remain in the OLE with exposure up to ~18 months.

What EAP outcomes did Rezolute report for tumor hyperinsulinism (RZLT)?

In the EAP cohort, 75% of patients receiving IV dextrose/TPN achieved complete discontinuation of infusions.

When will Rezolute (RZLT) discuss next steps with the FDA?

Rezolute plans to meet with the FDA in Q1 2026 under its Breakthrough Therapy Designation to align on a path forward.

What is the primary endpoint and timing for the upLIFT study (RZLT) in tumor HI?

upLIFT's primary endpoint is a ≥50% reduction in GIR; topline results are expected in H2 2026.

Did sunRIZE show any pharmacologic evidence of ersodetug activity in congenital HI?

Yes; target therapeutic drug concentrations and sensitive biomarker increases in circulating insulin were observed in active treatment groups.