Dear TrialNet Family,

We are thrilled to announce that the Teplizumab Prevention Study is the first to show clinical type 1 diabetes (T1D) can be delayed for a median of two years in children and adults at high risk. The results were announced on June 9, 2019 at the American Diabetes Association’s 79th Annual Scientific Sessions and published in the New England Journal of Medicine.

As we announce these breakthrough findings, We’d like to take a moment to thank everyone who made the Teplizumab (Anti-CD3) Prevention Study possible:

  • The families who participated—for being the focus of everything we do.
  • The TrialNet research team -- for upholding the highest research standards and taking such good care of participants.
  • Everyone at the National Institutes of Health (NIH), National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), JDRF and the American Diabetes Association-- for continued support of this important research. We also thank Congress for funding the Special Diabetes Program, which provides critical funding for NIH T1D research.
  • MacroGenics/Provention Bio for donating the study drugs and providing funds.

This is an incredible advancement that gets us one step closer to our ultimate goal: a future without T1D.


Kevan Herold, M.D.
TrialNet Teplizumab Study Chair
Professor of Immunobiology and Medicine, Yale University

Carla Greenbaum, M.D.
TrialNet Chair
Diabetes Program Director, Benaroya Research Institute at Virginia Mason

Study Details Completed

Previous clinical studies have shown the benefit of teplizumab in prolonging insulin production in people recently diagnosed with T1D.

This is the first study to test teplizumab’s ability to delay or prevent disease progression in those at high risk for developing T1D.

All study participants had two or more T1D autoantibodies and abnormal blood sugar levels (Stage 2 T1D) prior to enrollment, as identified by TrialNet Pathway to Prevention risk screening. Individuals in Stage 2 have a lifetime risk of clinical diagnosis (Stage 3 T1D) nearing 100%.

Researchers enrolled 76 people between the ages of 8 and 49; 55 were under age 18. All participants had at least one relative with type 1 diabetes.

Participants were randomly assigned to either the treatment group, which received a 14-day course of teplizumab, or the control group, which received a placebo. All participants regularly underwent oral glucose tolerance tests either until the study was completed or until they developed clinical type 1 diabetes.

Key Findings

  • This is the first study to show any drug can delay type 1 diabetes diagnosis a median of 2 years in adults and children at high risk.
  • 72% of people in the control group developed clinical diabetes, compared to only 43% of the teplizumab group.
  • The median time for people in the control group to develop clinical diabetes (stage 3) was just over 24 months, while those in the treatment group had an average of 48 months before progressing to clinical diabetes (stage 3).
  • Researchers observed, as with other trials involving teplizumab, short-term side effects of rash and low white blood cell counts.
  • Subgroups of individuals may have had a better response to therapy than others.

Next Steps

  • In addition to being able to accurately predict who is going to develop T1D, TrialNet has now found a way to delay it. This is an incredible advancement that gets us one step closer to our ultimate goal: a future without T1D.
  • We know immunotherapy can slow the progression T1D, and we now hope to conduct additional studies to look for ways to extend the benefits of teplizumab, while continuing to test other immune therapies. 
  • TrialNet is currently conducting two studies testing immune therapies to delay or prevent T1D: 
  • Samples collected during the Teplizumab Prevention Study are being studied to help researchers understand why some group of individuals had a better response to therapy than others.

In addition, TrialNet is continually planning and launching new studies. As always, we encourage family members of people with T1D to get screened through the Pathway to Prevention Study.

For Study Participants

A big thank you to our amazing participants who made this research possible! Teplizumab participant resources are available here.