- If approved, Tzield would be the first disease-modifying therapy to delay the progression of stage 3 T1D in adults and pediatric patients eight years of age and older recently diagnosed with stage 3 T1D
- Tzield is also being reviewed under the accelerated approval program
Paris, October 20, 2025. The US Food and Drug Administration (FDA) has accepted for expedited review the supplemental biologics license application (sBLA) for Tzield (teplizumab-mzwv) to delay the progression of stage 3 type 1 diabetes (T1D) in adults and pediatric patients eight years of age and older recently diagnosed with stage 3 T1D. The FDA nominated Tzield for the Commissioner's National Priority Voucher (CNPV) pilot program based on its potential to address a large unmet medical need. The CNPV program aims to shorten the review process from what normally takes 10-12 months to 1-2 months, while maintaining FDA's rigorous safety and efficacy standards.
"We welcome that Tzield has been accepted for expedited review by the FDA under the Commissioner’s National Priority Voucher pilot program, potentially enabling us to go further and faster for patients and lead the way with breakthrough science," said Olivier Charmeil, Executive Vice President, General Medicines, Sanofi. "This is a recognition of the breakthrough innovative profile of Tzield, its ability to potentially prevent the natural progression of T1D, and the significant unmet medical need that remains in this area which has seen limited treatment advances in the last 100 years.”
The sBLA is supported by the results from the PROTECT phase 3 study, which met its primary endpoint, evaluating preservation of beta cell function as assessed by significantly slowing the decrease in mean C-peptide levels (area under the curve [AUC] after a four-hour mixed meal tolerance test) at trial study completion, compared to placebo. Additionally, the sBLA builds on the clinical development program of Tzield including approximately~1,000 patients.
Adverse events observed in the PROTECT phase 3 study were consistent with previous studies. Most common adverse events were headache, nausea, rash, lymphopenia, leukopenia and gastrointestinal symptoms, consistent with the mode of action of cytokine release. 1.8% of those who received Tzield in the PROTECT study developed cytokine release syndrome possibly or probably related to Tzield.
Additionally, Tzield is being reviewed under the accelerated approval program, a pathway that allows the FDA to review therapies 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 requirement, the confirmatory BETA-PRESERVE phase 3 study (clinical study identifier: NCT07088068) was initiated recently and is currently enrolling participants.
Tzield is approved in the US, the UK, China, Canada, Israel, the Kingdom of Saudi Arabia, the United Arab Emirates, and Kuwait to delay the onset of stage 3 T1D in adults and pediatric patients eight years and older diagnosed with stage 2 T1D. Regulatory reviews are ongoing in the EU and 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.
The safety and efficacy of Tzield in stage 3 T1D have not yet been approved by any regulatory authority.
About PROTECT
PROTECT (clinical study identifier: NCT03875729) was a phase 3, randomized, double blind, placebo-controlled, multi-national study. It enrolled 328 children and adolescents (Tzield n=217, placebo n=111) aged eight-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 (approx. six months). All participants received standard-of-care medicines as required.
The primary objective of PROTECT was to determine whether Tzield could preserve beta cell function measured by C-peptide, compared to placebo. This was assessed via the trial’s primary endpoint, which measured the difference in mean change of C-peptide level (area under the time-concentration curve [AUC] measured after a four-hour mixed meal tolerance test) from baseline to Week 78 between both groups.
Key secondary endpoints included change in HbA1c, time in range as measured with a CGM, clinically important low blood sugar (hypoglycemia) events and exogenous insulin use. Time in range was defined as: ≥ 70 but ≤180 mg/dL. Clinically relevant hypoglycemic events were defined: level 2 hypoglycemia (<54 mg/dL / 3.0 mmol/L) and level 3 hypoglycemia as episodes of severe cognitive impairment requiring external assistance for recovery, even in the absence of a blood glucose reading.
Other secondary endpoints were adverse events and overall safety aspects, as well as pharmacokinetics and immunogenicity of Tzield. An observational extension study following participants for a further 42 months is ongoing.
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 approved in the US in November 2022 to delay the onset of Stage 3 type 1 diabetes in adults and children eight years and older diagnosed with stage 2 T1D. Today, it is also approved in the UK, China, Canada, Israel, the Kingdom of Saudi Arabia, the United Arab Emirates, and Kuwait for the same indication. Regulatory reviews are ongoing in the EU and other jurisdictions around the world.
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 condition 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 remain (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 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.
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