FDA Expands Teplizumab-mzwv Approval to Delay Stage 3 Type 1 Diabetes in Children as Young as 1 Year

The FDA has approved a supplemental biologic license application for teplizumab-mzwv (Tzield, Sanofi), expanding its approved age range from 8 years and older to as young as 1 year to delay the onset of stage 3 type 1 diabetes (T1D) in patients diagnosed with stage 2 T1D. The approval was granted under priority review, making teplizumab the first disease-modifying therapy available for children in this younger age group.¹

"This approval opens an important new chapter in diabetes care for young children with stage 2 T1D and their families," Kimber Simmons, MD, MS, associate professor of pediatrics at the Barbara Davis Center in Aurora, Colorado, said in a news release. "These children are often at the highest risk of progressing quickly and without warning. Delaying the onset of stage 3 T1D during the years when management is often most difficult—because of a child's small size and dependence on caregivers—could have a truly meaningful impact for families."¹

Mechanism of Action

Teplizumab is a CD3-directed monoclonal antibody that targets T cells involved in the autoimmune destruction of insulin-producing beta cells in the pancreas. By modulating the immune response early in the disease process, teplizumab works to slow the loss of beta cell function before clinical symptoms emerge. It was first approved by the FDA in November 2022 to delay the onset of stage 3 T1D in adults and children 8 years and older with stage 2 T1D, making it the first drug ever approved to alter the course of any autoimmune disease prior to clinical onset.²

Research has shown that teplizumab delays progression from stage 2 to stage 3 T1D by a median of 2 years in children and adults with multiple islet autoantibodies and early dysglycemia and that it is most effective when initiated before significant beta cell loss has occurred.³

Supporting Clinical Data: The PETITE-T1D Study

The expanded indication is supported by 1-year interim data from the PETITE-T1D phase 4 study (NCT05757713), a single-arm, open-label, multicenter study designed to evaluate the safety, tolerability, and pharmacokinetics of teplizumab specifically in children younger than 8 years with stage 2 T1D. The study enrolled 23 participants, all of whom received a 14-day course of once-daily intravenous teplizumab infusions. A prespecified interim analysis was conducted after 15 participants completed 1 year of follow-up.¹

Results indicated that teplizumab was safe and well tolerated in this younger population, with adverse events (AEs) consistent with those observed in prior studies and no new safety signals identified. The most commonly reported AEs in prior teplizumab research have included lymphopenia, rash, and headache—the majority of which occurred during or shortly after treatment and resolved without intervention.^2,4

"The autoimmune attack driving this disease often begins early in life, and the burden that autoimmune T1D poses in this very young population and their families is significant,” said Christopher Corsico, global head of development at Sanofi. "This approval underscores the importance of targeting the immune system early in autoimmune T1D, aiming to impact its natural progression by delaying the loss of insulin production in the pancreas.”¹

Regulatory Context and Current Approvals

Teplizumab previously held FDA breakthrough therapy designation and orphan drug designation, reflecting the rarity of presymptomatic T1D and the unmet need in this population. Beyond the US, teplizumab is also approved under the name Teizeild in the European Union, the United Kingdom, China, Canada, Israel, Saudi Arabia, the United Arab Emirates, Kuwait, and Brazil to delay the onset of stage 3 T1D in adults and pediatric patients 8 years and older with stage 2 T1D.¹

Separately, the FDA is reviewing teplizumab for a potential new indication to delay the progression of stage 3 T1D in patients 8 years and older who have recently been diagnosed with clinical disease, which could further expand the drug's role in T1D management.¹

REFERENCES

1. Sanofi's Tzield approved in the US to delay the onset of stage 3 type 1 diabetes in young children. News release. Sanofi. April 22, 2026. https://www.sanofi.com/en/media-room/press-releases/2026/2026-04-22-05-05-00-3278650

2. TrialNet research leads to FDA approval of first drug to delay type 1 diabetes. Type 1 Diabetes TrialNet. Accessed April 22, 2026. https://www.trialnet.org/our-research/completed-studies/teplizumab

3. Miller RG, Magliano DJ, Thomas NJ, Costacou T. Prevalence and incidence of Type 1 diabetes among children and adults in the United States and comparison with other countries. In: Lawrence JM, Casagrande SS, Herman WH, et al, eds. Diabetes in America [Internet]. National Institute of Diabetes and Digestive and Kidney Diseases; 2023. Accessed April 22, 2026. https://www.ncbi.nlm.nih.gov/books/NBK619992/

4. Herold KC, Gitelman SE, Gottlieb PA, Knecht LA, Raymond R, Ramos EL. Teplizumab: a disease-modifying therapy for Type 1 diabetes that preserves β-cell function. Diabetes Care. 2023;46(10):1848-1856. doi:10.2337/dc23-0675