FDA Approves Tzield for Patients 1 Year of Age to Delay Stage 3 Type 1 Diabetes

The FDA approved a supplemental biologic license application for teplizumab-mzwv (Tzield) to expand the indication from patients 8 years and older to as young as 1 year to delay the onset of stage 3 type 1 diabetes. The approval was granted under priority review and supported by 1-year data from the PETITE-T1D phase 4 study (NCT05757713).

"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,” Christopher Corsico, global head of development at Sanofi, said in a news release. "This approval underscores the importance of targeting the immune system early in autoimmune type 1 diabetes, aiming to impact its natural progression by delaying the loss of insulin production in the pancreas.”

Pharmacists must understand the specific disease progression that teplizumab-mzwv is designed to interrupt, as stage 2 type 1 diabetes is a presymptomatic phase characterized by the presence of 2 or more islet autoantibodies and abnormal blood sugar levels, known as dysglycemia. Although stage 1 also involves autoantibodies, it is defined by normal blood sugar levels, whereas the transition to stage 3 represents the point of clinical diagnosis where significant beta cell destruction leads to overt hyperglycemia and the need for daily insulin replacement.^1,2

Research indicates that the progression to stage 3 is often most rapid in younger children, making early intervention critical. Delaying this onset is particularly meaningful for families, as managing insulin therapy in very young children is complicated by their small size, variable physical activity, and difficulty communicating symptoms of hypoglycemia.^2,3

The PETITE-T1D trial was a single-arm, open-label study involving 23 participants with a mean age of 4.8 years. The treatment regimen remains consistent with the previously approved indication, requiring a 14-day course of consecutive daily intravenous infusions. Clinical data from the study showed that the estimated probability of participants remaining free from stage 3 progression at the 1-year mark was 89.6%, a result comparable to findings in older cohorts. For the pharmacist overseeing administration, it is important to note that serum concentrations of teplizumab typically peak on the final day of the 14-day infusion course before declining to near-quantification limits by day 28.^1,3

The safety profile in children under 8 years of age was found to be generally consistent with previous studies, with no new safety risks identified during the interim analysis. Every participant in the PETITE-T1D study experienced at least 1 treatment-emergent adverse event (AE), though the majority were mild to moderate in severity.³

The most frequently reported included vomiting, rash, and a transient decrease in lymphocyte and white blood cell counts. Notably, the rate of vomiting was higher in this younger population at 52.2% compared with 31.8% in older cohorts, potentially because younger children may not communicate early symptoms of nausea as effectively to trigger pre-emptive antiemetic use. Three participants in the study required discontinuation of treatment due to AEs such as anemia, elevated liver enzymes, and a serious maculopapular rash.

From a pharmacological perspective, teplizumab functions as a CD3-directed humanized monoclonal antibody that binds to the T cell receptor CD3ε chain. This mechanism of action leads to partial T cell exhaustion and a reduction in the expansion of autoreactive CD8+ T cells, thereby preserving the function of the remaining insulin-producing beta cells.^1,3

“We are starting to develop therapies that directly target the autoimmunity, and in diseases for which those therapies are available, presymptomatic and early screening should be considered (eg, teplizumab in presymptomatic T1D),” Jason Gaglia, MD, MMSc, an assistant professor of medicine at Harvard Medical School, said in an interview.⁴

Pharmacists should monitor for immunogenicity, as approximately 90% of the study participants tested positive for antidrug antibodies by the second week of treatment. Although these antibodies generally peak around week 12 and decline thereafter, neutralizing antibodies were detected in over half of the participants during the first 6 months of follow-up, which appeared to correlate with lower mean serum concentrations of the drug. Despite these findings, no clinically meaningful changes in hemoglobin A_1C levels were observed throughout the first 52 weeks of the study.

READ MORE: Diabetes Resource Center

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REFERENCES

1. Press Release: 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. Accessed April 22, 2026. https://www.sanofi.com/en/media-room/press-releases/2026/2026-04-22-05-05-00-3278650

2. Stages of type 1. Emory University School of Medicine. Accessed April 22, 2026. https://med.emory.edu/departments/pediatrics/divisions/endocrinology/research/what-is-diabetes/type-1-stages.html

3. Gitelman SE, Simmons K, Sherr JL, et al. Safety and pharmacokinetics of teplizumab in children less than 8 years of age with stage 2 type 1 diabetes. Diabetologia. 2026;69(2):330-342. doi:10.1007/s00125-025-06586-1

4. Stiles L. Type 1 Diabetes Increases Risk of Other Autoimmune Diseases. Drug Topics®. April 7, 2025. Accessed April 22, 2026. https://www.drugtopics.com/view/type-1-diabetes-increases-risk-of-other-autoimmune-diseases