- If approved, Tzield would be the first disease-modifying therapy to delay the onset of stage 3 T1D in children aged one and older diagnosed with stage 2 T1D
- Tzield slows disease progression by protecting the insulin-secreting beta cells of the pancreas
- The priority review is based on interim results from the PETITE-T1D phase 4 study
Paris, January 5, 2026. The US Food and Drug Administration (FDA) has accepted for priority review the supplemental biologic license application (sBLA) for Tzield (teplizumab-mzwv) to expand the current age indication from eight years and above, to as young as one year old and above to delay the onset of stage 3 type 1 diabetes (T1D) in patients diagnosed with stage 2 T1D. The sBLA is supported by the positive interim one-year data from the ongoing PETITE-T1D phase 4 study (clinical study identifier: NCT05757713), evaluating the safety and pharmacokinetics of Tzield in young children. The target action date for the FDA decision is April 29, 2026.
“This priority review emphasizes the urgent need for innovative therapies like Tzield which has the potential to prevent the natural progression of T1D by delaying the loss of endogenous insulin production. This might be particularly significant in this young population, as it is well documented that the autoimmune attack that drives this disease in many cases, begins, early in life,” said Christopher Corsico, Global Head of Development at Sanofi. “If approved, Tzield could represent an important advance for delaying the onset of stage 3 type 1 diabetes in early childhood, which would benefit patients and caregivers alike.”
Interim data for the PETITE-T1D phase 4 study was presented at the 51st Annual Conference of the International Society for Pediatric and Adolescent Diabetes and simultaneously published in Diabetologia.
Priority review is given to regulatory applications seeking approval for therapies that have the potential to provide significant improvements in the treatment, diagnosis, or prevention of serious conditions.
The safety and efficacy of Tzield in the PETITE-T1D population has not been approved by any regulatory authority.
About PETITE-T1D
PETITE-T1D (clinical study identifier: NCT05757713) is an ongoing phase 4 single-arm, non-randomized, open-label, multicentre study designed to assess the safety and pharmacokinetics of Tzield in children under eight years diagnosed with stage 2 T1D. Stage 2 T1D is defined by the presence of two or more T1D-related autoantibodies and dysglycaemia.
The study has enrolled 23 participants. The regimen consists of an intravenous infusion of Tzield once daily for 14 consecutive days. The study duration for each individual may last up to 26 months for follow up and monitoring.
About Tzield
Tzield (teplizumab-mzwv) is a CD3-directed monoclonal antibody. Tzield is the first and only disease-modifying therapy in autoimmune T1D; it was first approved in the US in November 2022 to delay the onset of stage 3 T1D in adults and children eight years and older diagnosed with stage 2 T1D. Today, it is also approved in China, the UK, Canada, Israel, the Kingdom of Saudi Arabia, the United Arab Emirates, and Kuwait for the same indication. In November 2025, the European Medicines Agency’s Committee for Medicinal Products for Human Use issued a positive recommendation for the same population (Tzield will be known as Teizeild in the EU). Other regulatory reviews are ongoing.
U.S. Indication and Important Safety Information
What is TZIELD?
TZIELD is a prescription medicine used to delay the onset of Stage 3 type 1 diabetes, which is when your body can’t make enough insulin on its own and may require insulin injections. TZIELD is for adults and children 8 years of age and older who have Stage 2 type 1 diabetes. This means that they have tested positive for 2 or more type 1 diabetes-related autoantibodies, have abnormal blood sugar levels, and do not have type 2 diabetes.
It is not known if TZIELD is safe and effective in children under 8 years of age.
IMPORTANT SAFETY INFORMATION
What is the most important information I should know about TZIELD?
TZIELD may cause serious side effects. These include:
- Cytokine release syndrome (CRS). Signs and symptoms may start during the first 5 days of TZIELD treatment and could include fever, nausea, feeling tired (fatigue), headache, muscle and joint pain, or increased liver enzymes in your blood. Tell your healthcare provider right away if you develop any signs and symptoms of CRS during treatment with TZIELD
- Decrease in white blood cells. TZIELD may cause a decrease in a type of white blood cell called lymphocytes. A decrease in white blood cells is a serious, but common side effect that can affect your body’s ability to fight infections. A decrease in white blood cell counts can happen after your first dose. Your white blood cell counts will start to go back to normal after your fifth dose of TZIELD. Some people may develop longer and more severe decreases in lymphocytes
Your healthcare provider will do blood tests to check your liver and your complete blood counts before you start treatment and during treatment with TZIELD. During and after your treatment with TZIELD, your healthcare provider will check for serious side effects, as well as other side effects, and treat you as needed. Your healthcare provider may temporarily or completely stop your treatment with TZIELD, if you develop liver problems, have a serious infection, or if your blood counts stay too low.
What should I tell my healthcare provider before receiving TZIELD?
Before or after receiving TZIELD, tell your healthcare provider about all your medical conditions, including if you:
- have a serious infection or an infection that does not go away or keeps coming back
- have recently received or are scheduled to receive an immunization (vaccine). TZIELD may affect how well a vaccine works. Tell your doctor that you are receiving TZIELD before receiving a vaccine
- are pregnant or plan to become pregnant. TZIELD may harm your unborn baby. Do not receive TZIELD during pregnancy and at least 30 days before a planned pregnancy
- are breastfeeding or plan to breastfeed. It is not known if TZIELD passes into your breast milk and if it can harm your baby. Talk to your healthcare provider about the best way to feed your baby if you receive TZIELD
Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.
What are the possible side effects of TZIELD? The most common side effects of TZIELD include:
- rash
- leukopenia (decrease in white blood cell counts)
- headache
These are not all of the possible side effects of TZIELD. Talk to your healthcare provider for more information and tell them about any side effects you notice. You may report side effects to the FDA at www.fda.gov/medwatch or 1-800-FDA-1088.
Please see Medication Guide and Prescribing Information.
About autoimmune T1D
T1D is a progressive autoimmune disease where the body’s ability to regulate blood sugar levels is impacted due to the gradual destruction of insulin-producing beta cells by one’s own immune system. There are four stages to the progression of T1D:
- In stage 1, the autoimmune attack to the beta cells has started, and this can be detected by the presence of 2 or more T1D-related autoantibodies in the blood. During stage 1, blood sugar levels are in a normal range (normoglycaemia). At this stage, T1D is presymptomatic.
- In stage 2 (also presymptomatic), in addition to the presence of 2 or more T1D-related autoantibodies, blood sugar levels are now abnormal (dysglycaemia) due to the progressive loss of beta cells/beta-cell function.
- Stage 3 (also known as clinical stage) comes once a significant portion of the beta cells have been destroyed. At this point, rising blood sugar levels reach the point of clinical hyperglycaemia (which defines diabetes), and many people will start to experience the classic symptoms that come with the onset of stage 3 T1D: increased thirst, frequent urination, unexplained weight loss, blurred vision, and generalized fatigue. Management of stage 3 T1D requires daily and burdensome insulin replacement therapy.
- Stage 4 is defined as long-standing autoimmune T1D, often accompanied by evidence of chronic diabetic complications, where little to no beta cells remain (it’s been estimated that the beta-cell mass is reduced by up to 95%). At this point, the T1D-related autoantibodies might not be present anymore in the blood, as most beta cells have been rendered useless by the autoimmune attack.
About Sanofi
Sanofi is an R&D driven, AI-powered biopharma company committed to improving people’s lives and creating compelling growth. We apply our deep understanding of the immune system to invent medicines and vaccines that treat and protect millions of people around the world, with an innovative pipeline that could benefit millions more. Our team is guided by one purpose: we chase the miracles of science to improve people’s lives; this inspires us to drive progress and deliver positive impact for our people and the communities we serve, by addressing the most urgent healthcare, environmental, and societal challenges of our time.
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