Sanofi’s Tzield approved in the US as the first disease-modifying therapy for patients recently diagnosed with stage 3 type 1 diabetes

• Accelerated approval in children aged eight to 17 years old recently diagnosed with stage 3 T1D to delay the decline in endogenous insulin production
• Approval based on the PROTECT phase 3 study and additional data from the global clinical development program from over 900 patients who received Tzield

 The US Food and Drug Administration (FDA) has granted accelerated approval to Tzield (teplizumab-mzwv) to delay the decline in endogenous (own) insulin production in children aged eight to 17 years recently diagnosed with stage 3 T1D. Tzield is not effective as a disease-modifying therapy in non-autoimmune dysglycemic conditions.

“We now have a novel therapy that targets the autoimmune and progressive nature of stage 3 type 1 diabetes,” said Aaron J. Kowalski, PhD, CEO of Breakthrough T1D. “Approximately 64,000 people are diagnosed with T1D every year. We are excited that the approval of Tzield in this indication provides a treatment option for certain patients diagnosed in stage 3 T1D, which is when many start experiencing common symptoms of the disease.”

The approval was supported by data from the PROTECT phase 3 study (clinical study identifier: NCT03875729), evaluating beta cell function as assessed by significantly slowing the decrease in mean C-peptide levels (area under the curve after a four-hour, mixed-meal tolerance test; difference in least-squares means 0.13 pmol/mL; 95% confidence interval: 0.09-0.17; p<0.001) at trial completion, compared to placebo, as well as data from the broader clinical development program that included over 900 patients who received Tzield. Adverse events observed in the PROTECT phase 3 study were consistent with previous studies.

The most common adverse reactions were lymphopenia, vomiting, rash, leukopenia, diarrhea, neutropenia, increased liver transaminase, and headache. Serious events such as cytokine release syndrome and life-threatening cases of viral reactivation have been reported with Tzield. Patients who are immunocompromised are at increased risk for viral reactivation.

This indication is granted under accelerated approval based on evidence of reduced C-peptide decline. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory study(ies).

Medicines that receive accelerated approval are intended to treat serious conditions that fill an unmet medical need, based on a surrogate endpoint reasonably likely to predict clinical benefit. In line with this, the confirmatory BETA-PRESERVE phase 3 study (clinical study identifier: NCT07088068) was initiated and is currently enrolling participants.

"We welcome this accelerated approval by the FDA, which recognizes the potential of Tzield to delay the progression of recently diagnosed stage 3 T1D in children aged eight to 17 years,” said Christopher Corsico, Global Head of Development, Sanofi. “Tzield will now offer a new pathway in the treatment paradigm of stage 3 T1D, one that we hope will further enable healthcare providers in the US to take a more proactive approach to disrupt the underlying autoimmune attack against insulin-producing beta cells.”

Prior to this approval in recently diagnosed stage 3 T1D, in April 2026, the FDA expanded the indication to delay the onset of stage 3 T1D in adults and children eight years and older with stage 2 T1D, to include children aged one year and above. It is also approved to delay the onset of stage 3 T1D in adults and children eight years and older with stage 2 T1D in the UK, the EU (under the name Teizeild), China, Australia, Canada, Israel, Saudi Arabia, the UAE, Kuwait, Brazil and Switzerland. Regulatory reviews are ongoing in other jurisdictions around the world. Tzield was previously designated by the FDA as breakthrough therapy and was granted orphan drug designation, for investigational medicines that treat rare diseases affecting fewer than 200,000 people in the US.