Teplizumab (Tzield) is the first FDA-approved disease-modifying drug for type 1 diabetes. Given as a 14-day intravenous infusion course, it delays progression from Stage 2 to clinical type 1 diabetes by a median of about 2 to 3 years. Approval is for adults and pediatric patients age 8 and older with Stage 2 T1D — identified via islet autoantibody screening.
What Teplizumab Is
Teplizumab is a humanized monoclonal antibody that binds to the CD3 receptor on T lymphocytes. By engaging CD3 with modified Fc binding, teplizumab modulates the T-cell response that drives beta-cell destruction in type 1 diabetes — slowing autoimmune attack on the islets without producing global immunosuppression.
It was developed over more than two decades before becoming the first FDA-approved disease-modifying therapy for T1D in November 2022. Marketing rights are held by Sanofi (acquired through Provention Bio in 2023).
How It Works
- Binds CD3 on T cells, inducing partial and transient signaling
- Selectively depletes or exhausts pathogenic effector T cells while sparing regulatory T cells (Tregs)
- Restores immune tolerance to islet antigens, at least temporarily
- Slows the rate of beta-cell destruction
- Does not produce broad immunosuppression like conventional anti-rejection drugs
The Stages of Type 1 Diabetes
| Stage | Definition | Symptoms |
|---|---|---|
| Stage 1 | ≥2 islet autoantibodies, normal glucose tolerance | None |
| Stage 2 | ≥2 islet autoantibodies, dysglycemia (impaired glucose tolerance or A1C ≥5.7%) | None or subtle |
| Stage 3 | Clinical diabetes — meets standard diagnostic criteria | Polyuria, polydipsia, weight loss, often DKA |
Teplizumab’s approved indication is Stage 2 — the window before clinical diabetes appears.
The TN-10 Trial
The pivotal trial (Herold et al., NEJM 2019) randomized 76 autoantibody-positive relatives of people with T1D to a single 14-day course of teplizumab or placebo.
| Outcome | Teplizumab | Placebo |
|---|---|---|
| Median time to clinical T1D | ~48.4 months | ~24.4 months |
| Median delay versus placebo | ~24 months (~2 years) | — |
| Proportion diagnosed at 2 years | ~28% | ~57% |
| Hazard ratio for progression | 0.41 | — |
With extended follow-up published in 2021, the median delay was approximately 3 years. About 22 percent of teplizumab-treated participants had still not progressed at 5 years.
Who Qualifies
- Adults and pediatric patients age 8 or older
- Two or more islet autoantibodies (GAD65, IA-2, ZnT8, insulin autoantibody, ICA)
- Dysglycemia on oral glucose tolerance test (OGTT) or A1C 5.7% or higher
- Not yet diagnosed with clinical (Stage 3) type 1 diabetes
Candidates are often identified through:
- TrialNet Pathway to Prevention (free for relatives of people with T1D)
- T1Detect (JDRF program, ages 2.5 to 45)
- ASK (Autoimmunity Screening for Kids in Colorado)
- Routine testing in pediatric clinics with strong family history
How Tzield Is Given
- 14 consecutive daily intravenous infusions
- Each infusion lasts at least 30 minutes plus monitoring
- Premedication for first 5 days: acetaminophen, antihistamine, antiemetic
- Dose escalates over the first 4 days, then a maintenance dose
- Given in infusion centers — coordination with endocrinology and infusion logistics required
- Single course; not repeated
Side Effects
Common:
- Lymphopenia — almost universal, usually transient (resolves within weeks)
- Rash
- Headache
- Elevated liver enzymes
- Nausea and infusion-related reactions
- Fever, fatigue, myalgia
Serious:
- Cytokine release syndrome — fever, hypotension, can be severe
- Serious infections — vaccinations should be up to date before infusion
- Live vaccines should be avoided for 2 weeks before, during, and 6 weeks after the course
- Hypersensitivity reactions
Monitoring Schedule
- Baseline: CBC, LFTs, EBV/CMV serology, vaccinations updated
- Daily during infusion: vitals, CBC at intervals
- Weekly post-infusion for several weeks: CBC, LFTs
- Long-term: glucose tolerance and autoantibody monitoring to track delay
Cost and Insurance
The list price for a full 14-day course is approximately $193,900 in the US (Sanofi pricing data). Insurance coverage has been expanding since approval, with many commercial plans covering it as a specialty medical benefit. Sanofi runs a patient support program (Tzield Pathway) that helps with prior authorization, financial assistance, and travel costs for some patients.
Where Teplizumab Fits
Teplizumab is the first immune-modifying T1D drug to reach market. Other approaches in development for T1D include verapamil (β-cell preservation), islet cell transplant, pancreas transplant, and stem cell therapy. For broader context, see our overview of treatment and complications and related conditions.
What Teplizumab Does Not Do
- Does not cure type 1 diabetes
- Does not reverse established (Stage 3) diabetes
- Does not eliminate the need for eventual insulin in most treated patients
- Does not work in everyone — some patients still progress to clinical T1D within a year
Its role is to extend the pre-clinical window — postponing daily insulin, complications risk accumulation, and the lifestyle adjustment of clinical T1D by several years.
Practical Considerations Before Starting
- Confirmed Stage 2 T1D with documented autoantibodies and dysglycemia
- Updated vaccinations including any non-live boosters needed
- Avoiding live vaccines for the relevant window
- Arranging 14 consecutive infusion days — significant time commitment
- Discussing realistic expectations: a delay, not a cure
- Insurance authorization typically needed; specialty pharmacy/infusion coordination
Ongoing Research
- Combination trials of teplizumab with other immune-modifying or beta-cell-supportive agents
- Pediatric expansion below age 8
- Use in newly diagnosed Stage 3 T1D to preserve residual beta-cell function (PROTECT trial showed preservation of C-peptide)
- Repeat dosing studies
The Bottom Line
Teplizumab (Tzield) is a one-time 14-day IV infusion course that delays the onset of clinical type 1 diabetes by a median of about 2 to 3 years in adults and children age 8 and older with Stage 2 disease (two or more islet autoantibodies plus dysglycemia). It is the first disease-modifying drug for T1D and was approved in 2022. Common side effects include transient lymphopenia, rash, and elevated liver enzymes; serious risks include cytokine release syndrome and infection. The list price is around $193,900 per course, with insurance and patient-assistance programs covering many patients. Talk to an endocrinologist about autoantibody screening through TrialNet or T1Detect if you have a family history of T1D.
