TN-10: Teplizumab to delay clinical type 1 diabetes in at-risk relatives (Stage 2)
What this study tests
A landmark NIH/TrialNet trial showing that a single 14-day course of the anti-CD3 antibody teplizumab delayed the clinical onset of type 1 diabetes by roughly 2 years (median, extended to ~2.5-3 years on longer follow-up) in high-risk relatives with Stage 2 disease. It became the basis for the FDA approval of Tzield in 2022, the first drug shown to delay type 1 diabetes.
Editorial review: .
Registry checked: 2026-09-17. Registry’s own update: 2020-08-05.
Most recent recorded citation date: 2021-03-01. Only explicit date metadata is included; an undated citation may be newer. This does not mean every claim was reviewed on that date.
Trial status, labels and access can change between reviews. How we review the evidence · How to read the evidence
Evidence at a glance
- Who can enter the study?
- Relatives with at least two islet autoantibodies and dysglycemia (stage 2 T1D), without clinical stage 3 disease. The current registry lists ages 8–45, while the published enrolled cohort ranged from approximately 8 to 49 years; the historical study population must not be mistaken for today’s treatment label. Registered eligibility ↗Enrollment criteria describe who may enter. They do not establish who was analyzed or the denominator for a reported result.
- Reported benefit and results
- A single 14-day teplizumab course delayed clinical diagnosis: median time to clinical stage 3 T1D was 48.4 months with teplizumab versus 24.4 months with placebo (hazard ratio 0.41) in the 2019 primary report, and 59.6 versus 27.1 months on extended follow-up (median ~923 days). Clinical stage 3 T1D developed in 43% of the teplizumab group versus 72% of placebo; on longer follow-up 50% of treated participants remained free of stage 3 disease versus 22% of placebo. The main side effects were rash and transient lymphopenia.Read the result sources and their limitations →
- Important harms
- Read the reported results, safety discussion and original sources. A separate harms summary is not available; this does not establish safety.
- Research access and approval
- Study regions: United States, European Union, Canada. A trial listing does not establish product approval or current recruitment at a particular site. Check the study’s current entry requirements.
- What remains uncertain?
- Read the full discussion and original sources for study limitations. Planned endpoints and completion dates are not results.
Research status alone does not establish approval, clinical benefit or local availability.
Primary endpoints
- Time from randomization to clinical diagnosis of type 1 diabetes (Stage 3), assessed by oral glucose-tolerance tests every 6 months
The full picture
Study and population
TN-10 tested one 14-day course of teplizumab against placebo in 76 relatives with at least two islet autoantibodies and dysglycemia. They already had stage 2 T1D, but had not developed clinical stage 3 disease. Forty-four received teplizumab and 32 placebo; 72% were aged 18 or younger. The published cohort ranged from approximately 8 to 49 years. Primary report; NIH population summary.
Results
The 2019 paper reported median time to stage 3 of 48.4 months with teplizumab versus 24.4 months with placebo, with a hazard ratio of 0.41. Clinical disease developed in 43% versus 72% during that analysis. Rash and transient lymphopenia were expected treatment effects. This was a small randomized trial of a selected population; it did not test repeated preventive courses. Primary report.
The subsequent follow-up reported median times of 59.6 versus 27.1 months; 50% versus 22% had not progressed to stage 3 at that analysis. This is longer follow-up of the same trial, not an independent replication. Follow-up publication.
How to interpret it now
Delayed progression does not mean autoimmune diabetes has been cured or permanently prevented. The trial’s participants and regimen must be distinguished from later regulatory expansions. See the current teplizumab record for country-specific indications, the current safety label and access limitations.
Sources
- [1]An Anti-CD3 Antibody, Teplizumab, in Relatives at Risk for Type 1 Diabetes. · Peer-reviewed study · 2019-06-09
- [2]
- [3]
- [4]Teplizumab improves and stabilizes beta cell function in antibody-positive high-risk individuals. · Peer-reviewed study · 2021-03-01
- [5]U.S. Food and Drug Administration. Drug Trials Snapshots: TZIELD. *FDA* (2022) · Regulatory decision
- [6]NIH: Drug delays type 1 diabetes in people at high risk · Open-source community · 2019-06-10