- 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
Paris, June 13, 2026. 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.
About PROTECT
PROTECT was a phase 3, randomized, double blind, placebo-controlled, multinational study. It enrolled 328 children and adolescents (Tzield n=217, placebo n=111) aged eight to 17 years diagnosed with clinical stage 3 T1D in the preceding six weeks; randomization ratio of Tzield to placebo was 2:1. Participants received a first course of 12 daily infusions (of either Tzield or placebo) at randomization, followed by a second course of 12 daily infusions after 26 weeks (approximately six months). All participants received standard-of-care medicines as required.
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 (normoglycemia). 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 (dysglycemia) 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 hyperglycemia (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-cell function remains (it’s been estimated that 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 Tzield
Tzield (teplizumab) is a CD3-directed monoclonal antibody. Tzield is the first disease- modifying therapy in autoimmune T1D; it was 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. In April 2026, the FDA expanded this indication to include children aged one year and above. Today, it is also approved to delay the onset of stage 3 T1D in adults and children eight years and older with stage 2 in the UK, the EU (under the name Teizeild), China, Australia, Canada, Israel, Saudi Arabia, the UAE, Kuwait, Brazil and Switzerland. Other regulatory reviews are ongoing.
What is TZIELD?
TZIELD is a prescription medicine used to:
- delay the onset of Stage 3 type 1 diabetes (T1D) in adults and children 1 year of age and older who have Stage 2 T1D.
- delay the decline in insulin produced by the body (endogenous) in children 8 to 17 years of age who were recently diagnosed with Stage 3 T1D.
It is not known if TZIELD is safe and effective in children under 1 year of age who have Stage 2 T1D.
It is not known if TZIELD is safe and effective in children under 8 years of age who have Stage 3 T1D.
There is limited evidence of TZIELD being safe and effective in people 45 years of age and older with Stage 2 T1D.
TZIELD is not effective as a disease modifying therapy in non-autoimmune dysglycemic conditions. These are conditions when your blood sugar goes too high and is not caused by your immune system.
Do not take TZIELD if you have a weakened immune system (immunocompromised) or have an active viral infection such as EBV or CMV infection.
IMPORTANT SAFETY INFORMATION
What is the most important information I should know about TZIELD?
TZIELD may cause serious side effects, including:
- Viral Reactivation. Epstein-Barr virus (EBV) and cytomegalovirus (CMV) are common viruses that may stay inactive in your body after an initial infection. TZIELD may cause these viruses to become active again which, especially in people with a weakened immune system, can become serious and potentially life-threatening. These infections can happen during treatment with TZIELD and for up to 2 months after your last dose. Your healthcare provider will test you for active EBV and CMV infections before treatment with TZIELD. Contact your healthcare provider right away if you develop symptoms of an infection during or after treatment with TZIELD (such as fever, swollen glands, or fatigue).
- Cytokine release syndrome (CRS). Signs and symptoms may start during the first 5 days of TZIELD treatment and could include fever, nausea (with or without vomiting), 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.
- Serious Infections: Treatment with TZIELD may lower your immune system’s ability to fight infections, which may increase your risk of getting a serious infection. TZIELD is not recommended if you currently have a serious infection, or an infection that keeps coming back or does not go away (chronic infection), other than a minor skin infection. Contact your healthcare provider right away if you develop symptoms of an infection during or after treatment with TZIELD such as: fever or chills; redness, warmth, or swelling of the skin; feeling tired; cough or shortness of breath; severe stomach pain or diarrhea.
- 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 of any treatment course. 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 for active infections, verify your liver function 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 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 viral reactivation, 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 any of the conditions or symptoms listed in the section “What is the most important information I should know about TZIELD?”
• have a weakened immune system, including if you have Down syndrome.
• have a serious infection or an infection that does not go away or keeps coming back (chronic).
• have recently received or are scheduled to receive an immunization (vaccine). TZIELD may affect how well a vaccine works. Tell your healthcare provider that you are receiving treatment with TZIELD before receiving a vaccine. Your healthcare provider will tell you when you can safely receive any vaccine before and after the treatment with TZIELD
• 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.
If you become pregnant while taking TZIELD, you are encouraged to report your pregnancy to us at our Adverse Event reporting line at 1-800-633-1610 or visit https://ae.reporting.sanofi.
• 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?
TZIELD may cause serious side effects including:
- See “What is the most important information I should know about TZIELD?”
- Allergic (hypersensitivity) reactions: Serious allergic reactions can happen while receiving TZIELD. Your healthcare provider will watch you closely while you are receiving TZIELD and after your infusion for signs of a reaction. Tell your healthcare provider right away if you have any of the following symptoms of an allergic reaction:
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The most common side effects of TZIELD include:
• decrease in white blood cell counts
• vomiting
• rash
• diarrhea
• increase in liver enzyme levels
• headache
These are not all of the possible side effects of TZIELD. For more information, ask your healthcare provider or pharmacist. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects to us at 1-800-633-1610 or visit https://ae.reporting.sanofi.
Please see full Prescribing Information, including Risk of SERIOUS SIDE EFFECTS and Medication Guide.
About Sanofi
Sanofi is an R&D driven, AI-powered biopharma company committed to improving people’s lives and delivering 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. Sanofi is listed on EURONEXT: SAN and NASDAQ: SNY
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