Tzield (teplizumab) is the first medicine that can delay type 1 diabetes. It is given as a short course of daily IV infusions to people who have diabetes autoantibodies and early blood-sugar changes but no symptoms yet (stage 2). In 2026 its approval expanded to children as young as age 1 and to children ages 8–17 who were just diagnosed with type 1 diabetes.
Type 1 diabetes is an autoimmune disease: the immune system gradually destroys the insulin-producing beta cells of the pancreas. This process starts months to years before symptoms appear, and it can be detected with a simple blood test for diabetes autoantibodies. Tzield is designed to intervene during that window. See our type 1 diabetes overview for more background.
The Three Stages of Type 1 Diabetes
| Stage | What's happening | Symptoms? |
|---|---|---|
| Stage 1 | 2 or more diabetes autoantibodies, normal blood sugar | None |
| Stage 2 | 2 or more autoantibodies plus abnormal blood sugar (dysglycemia) | None |
| Stage 3 | Clinical type 1 diabetes; insulin is needed | Thirst, frequent urination, weight loss, possible DKA |
Who Qualifies for Tzield?
- To delay type 1 diabetes: adults and children age 1 and older with stage 2 type 1 diabetes (originally approved in 2022 for age 8 and up; expanded to age 1 and up in April 2026)
- For newly diagnosed type 1 diabetes: children and teens ages 8–17 diagnosed with stage 3 type 1 diabetes within the past few weeks who still make some of their own insulin (approved August 2026). Here the goal is to slow the loss of the body's own insulin production
The newly-diagnosed approval is an accelerated approval, based on preserving C-peptide (a marker of the body's own insulin production). A follow-up study is underway to confirm the long-term clinical benefit.
Screening: Finding Stage 1 and 2
Most people who could benefit don't know they're in an early stage. Screening is especially worth discussing if you have:
- A parent, brother, sister, or child with type 1 diabetes (family members have about a 15 times higher risk)
- Other autoimmune conditions such as Hashimoto's thyroiditis or celiac disease
- Unexplained episodes of high blood sugar or a borderline A1c at a young age
Screening is a blood test for diabetes autoantibodies (such as GAD65, insulin, IA-2, and ZnT8). Free screening for relatives is also available through research programs such as TrialNet. If antibodies are found, an oral glucose tolerance test or other tests show whether someone is in stage 1 or stage 2.
How Tzield Is Given
- Stage 2 (delay): one 30-minute IV infusion every day for 14 days in a row, at an infusion center
- Newly diagnosed (ages 8–17): two 12-day courses of daily infusions, about 6 months apart
- Before infusions start: blood tests (blood counts and liver tests) and a check for active infections. Vaccines should be brought up to date beforehand — live vaccines must be given well before treatment
- Medicines such as acetaminophen, an antihistamine, and an anti-nausea medicine are often given before infusions during the first several days to reduce reactions
How Well Does It Work?
In the pivotal trial of relatives with stage 2 type 1 diabetes, people who received Tzield developed stage 3 type 1 diabetes a median of about 2 years later than those who received placebo, and some stayed diabetes-free much longer. In the PROTECT trial of 328 children ages 8–17 with new type 1 diabetes, those treated with Tzield lost significantly less of their own insulin production over 78 weeks than those on placebo.
Delaying type 1 diabetes matters: it can mean years without daily insulin injections or fingersticks, a lower chance of being diagnosed in DKA, more time for a child to grow and for the family to prepare, and possibly fewer long-term complications.
Side Effects
Most side effects happen during or shortly after the infusion course and go away afterward:
- Lymphopenia (temporary drop in white blood cells) — expected in most people, usually recovering within weeks
- Rash, headache, nausea or vomiting
- Changes in liver blood tests
- Cytokine release syndrome — fever, tiredness, muscle and joint aches, usually in the first days of treatment
⚠️ Boxed warning: Tzield can cause serious, potentially life-threatening reactivation of viruses such as Epstein-Barr virus (EBV) and cytomegalovirus (CMV). It should not be given to people with an active serious infection or a weakened immune system. Tell your care team right away about fever, sore throat, swollen glands, or other signs of infection during or after treatment.
Is Tzield Right for You or Your Child?
Tzield is a specialized therapy, and the decision involves screening results, age, overall health, timing, and insurance coverage. If you or a family member has tested positive for diabetes autoantibodies, or you have a strong family history of type 1 diabetes, talk with your endocrinologist about whether screening or Tzield makes sense and where infusions are available.
Key Takeaways
- Tzield (teplizumab) is the first medicine that can delay the onset of clinical type 1 diabetes
- Approved for stage 2 type 1 diabetes in adults and children age 1 and older (expanded April 2026)
- Also approved (August 2026) for children 8–17 newly diagnosed with type 1 diabetes, to preserve their own insulin production
- Given as daily IV infusions: 14 days for stage 2, or two 12-day courses for new diagnosis
- Delayed stage 3 diabetes by a median of about 2 years in the main trial; it is not a cure
- Relatives of people with type 1 diabetes should ask about autoantibody screening
Our Team Can Help
All five of our providers diagnose and manage endocrine conditions. Book with any member of our team:
Book an Appointment → or call 832-968-7003