Teplizumab receives US approval for recently diagnosed stage 3 type 1 diabetes

FDA grants accelerated approval for teplizumab to help preserve insulin production in children with recently diagnosed stage 3 type 1 diabetes

The FDA has granted accelerated approval to teplizumab-mzwv to delay the decline in endogenous insulin production in children aged 8–17 years recently diagnosed with stage 3 type 1 diabetes (T1D).¹ The approval marks the first disease-modifying treatment option for this population.

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T1D is an autoimmune disease characterized by immune-mediated destruction of pancreatic β-cells, resulting in insulin deficiency and the need for lifelong exogenous insulin therapy. Stage 3 disease represents the symptomatic phase of T1D, when β-cell dysfunction has progressed sufficiently to cause clinical hyperglycemia.²

The approval was supported by PROTECT (NCT03875729), a phase 3, randomized, double-blind, placebo-controlled, multinational study evaluating whether teplizumab could slow β-cell loss in children and adolescents with newly diagnosed stage 3 T1D.^3,4 The study enrolled 328 participants aged 8–17 years who had been diagnosed within the previous 6 weeks and randomized them 2:1 to teplizumab or placebo. Participants received two 12-day courses of intravenous treatment, with the second course administered approximately 26 weeks after the first.

The primary endpoint was change from Baseline in stimulated C-peptide levels at Week 78, measured by area under the curve during a 4-hour mixed-meal tolerance test. Teplizumab significantly slowed the decline in mean C-peptide levels compared with placebo, with a least-squares mean difference of 0.13 pmol/mL (95% CI 0.09–0.17; p<0.001). Key secondary endpoints included insulin dose, HbA1c, time in target glucose range and clinically important hypoglycemic events; these showed numerical trends but did not demonstrate statistically significant differences.

The safety profile was consistent with previous studies. Common adverse reactions included lymphopenia, vomiting, rash, leukopenia, diarrhea, neutropenia, increased liver transaminases and headache. Serious events, including cytokine release syndrome and life-threatening cases of viral reactivation, have also been reported.

In clinical practice, teplizumab introduces a new opportunity to intervene soon after diagnosis in selected children and adolescents with stage 3 T1D, with the aim of preserving endogenous insulin production. However, the approval is based on a surrogate endpoint, and continued approval may depend on verification and description of clinical benefit in confirmatory studies, including the ongoing phase 3 BETA-PRESERVE study.

References

1. Sanofi. Sanofi’s Tzield approved in the US as the first disease-modifying therapy for patients recently diagnosed with stage 3 type 1 diabetes [Press release]. June 12, 2026. Available at: https://www.sanofi.com/en/media-room/press-releases/2026/2026-06-12-22-09-58-3311349 (accessed June 16, 2026).
2. DiMeglio LA, Evans-Molina C, Oram RA. Type 1 diabetes. Lancet. 2018;391:2449–62.
3. Ramos EL, Dayan CM, Chatenoud L, et al. Teplizumab and β-cell function in newly diagnosed type 1 diabetes. N Engl J Med. 2023;389:2151–61.
4. ClinicalTrials.gov. A study of teplizumab in children and adolescents with recent-onset type 1 diabetes. ClinicalTrials.gov Identifier: NCT03875729. Available at: https://clinicaltrials.gov/study/NCT03875729 (accessed June 16, 2026).