Sanofi’s Tzield Approved as First Disease-Modifying Therapy for Recently Diagnosed Stage 3 Type 1 Diabetes

Sanofi’s Tzield Approved as First Disease-Modifying Therapy for Recently Diagnosed Stage 3 Type 1 Diabetes

The U.S. Food and Drug Administration (FDA) has granted accelerated approval to Sanofi’s Tzield (teplizumab-mzwv) to delay the decline of endogenous insulin production in children aged 8 to 17 years recently diagnosed with clinical Stage 3 type 1 diabetes (T1D). This represents a major expansion of the drug's therapeutic footprint, making it the first disease-modifying therapy approved for patients who have already progressed to clinical diagnosis.

Prior to this approval, Tzield was only indicated to delay the onset of Stage 3 T1D in patients aged 8 and older (expanded to age 1 and older in April 2026) with presymptomatic Stage 2 T1D.

Clinical Evidence from PROTECT

The accelerated approval was supported by data from the Phase 3 PROTECT clinical trial (NCT03875729), which evaluated beta-cell function in 328 children and adolescents diagnosed with clinical Stage 3 T1D within the preceding six weeks. The trial randomized participants 2:1 to receive either Tzield (n=217) or placebo (n=111) as two courses of 12 daily infusions administered 26 weeks apart.

• Primary Endpoint: Tzield significantly slowed the decrease in mean C-peptide levels (area under the curve after a 4-hour mixed-meal tolerance test) compared to placebo at trial completion.
• Statistical Significance: The difference in least-squares means was 0.13 pmol/mL (95% confidence interval: 0.09–0.17; p<0.001).
• Safety Profile: Adverse events were consistent with previous studies. The most common reactions included lymphopenia, vomiting, rash, leukopenia, diarrhea, neutropenia, increased liver transaminases, and headache. Serious risks include cytokine release syndrome (CRS) and life-threatening viral reactivation.

Confirmatory Study and Next Steps

Because this indication was granted under the FDA's accelerated approval pathway based on the surrogate endpoint of C-peptide decline, continued approval is contingent upon verification of clinical benefit.¹ Sanofi has already initiated and is currently enrolling participants in the confirmatory Phase 3 BETA-PRESERVE study (NCT07088068) to fulfill this requirement.

Verbatim Quotes

• Aaron J. Kowalski, PhD, CEO of Breakthrough T1D:

“We now have a novel therapy that targets the autoimmune and progressive nature of stage 3 type 1 diabetes. 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.”

• Christopher Corsico, Global Head of Development, Sanofi:

"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. 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."