Sanofi’s Tzield receives US approval as the first disease-modifying therapy for patients newly diagnosed with stage 3 type 1 diabetes

The US Food and Drug Administration has granted accelerated approval to Tzield (teplizumab-mzwv) for delaying the decline in endogenous insulin production among children aged eight to 17 who have recently been diagnosed with stage 3 T1D. The therapy does not act as a disease-modifying treatment in dysglycemic conditions that are not autoimmune in nature.

“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.”

Supporting evidence for the approval came from the PROTECT phase 3 study, which assessed beta cell function and found a significant slowing in the decline of mean C-peptide levels measured against placebo by trial completion, alongside data drawn from the wider clinical development programme encompassing over 900 patients who received Tzield. Adverse events recorded during the PROTECT phase 3 study matched those seen in earlier research.

Lymphopenia, vomiting, rash, leukopenia, diarrhea, neutropenia, elevated liver transaminase levels, and headache emerged as the most frequently reported adverse reactions. More serious complications, including cytokine release syndrome and instances of life-threatening viral reactivation, have also been documented with Tzield use, with immunocompromised patients facing a heightened risk of viral reactivation.

This particular indication has been granted under accelerated approval on the strength of evidence showing reduced C-peptide decline. Whether approval continues for this indication may depend on confirmation and further characterisation of clinical benefit through subsequent studies.

Accelerated approval pathways exist for medicines treating serious conditions with unmet medical need, where a surrogate endpoint is judged reasonably likely to predict clinical benefit. Reflecting this framework, the confirmatory BETA-PRESERVE phase 3 study has now begun and is actively recruiting 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.”

Ahead of this latest approval covering newly diagnosed stage 3 T1D, the FDA had already broadened Tzield’s indication back in April 2026 to delay the onset of stage 3 T1D in adults and children aged eight and above living with stage 2 T1D, extending eligibility down to children as young as one year old. The therapy also carries approval for delaying stage 3 T1D onset in those eight and older with stage 2 T1D across the UK, the EU (marketed there as Teizeild), China, Australia, Canada, Israel, Saudi Arabia, the UAE, Kuwait, Brazil, and Switzerland, with regulatory assessments continuing elsewhere around the globe. Tzield previously earned breakthrough therapy designation from the FDA and was also granted orphan drug status, a designation reserved for investigational medicines targeting rare diseases affecting fewer than 200,000 people in the US.

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