Dear TrialNet Family,

TrialNet has been investigating the role of oral insulin in T1D for nearly 20 years. Most recently, we completed the Oral Insulin Prevention Study—the largest study of its kind, conducted over 10 years with 560 relatives of people with T1D.

As we announce the study findings, I want to take this opportunity to recognize this incredible accomplishment and thank everyone involved.

First and foremost, on behalf of everyone in TrialNet and type 1 diabetes researchers around the world, I want to say a heartfelt thank you to the families who participated in the study. Please know you have and will continue to make a difference in our mission to find a way to delay, prevent and ultimately cure type 1 diabetes. 

To the TrialNet nurses and healthcare providers who took such great care of participating families and upheld the highest research standards, we greatly appreciate your hard work and dedication. 

To fellow researchers and scientists in and out of TrialNet, let this be a reminder that our time and efforts are impactful.

We would also like to thank the National Institutes of Health (NIH), National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), the American Diabetes Association and JDRF for their continued support. We also thank Congress for funding the Special Diabetes Program, an important program that provides critical funding for NIH T1D research.

I look forward to sharing more accomplishments as we work toward our ultimate goal: a future without T1D.


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

Study Details Completed

Topline results of this 10-year TrialNet study were shared at the American Diabetes Association’s 77th Scientific Sessions on June 12, 2017. Now, we share them with you.

  • The largest of its kind, the Oral Insulin Prevention Study was conducted over 10 years and included 560 relatives of people with type 1 diabetes.
  • Participants were divided into four groups according to their diabetes-related autoantibodies and level of insulin producing beta cells.
    • All participants were in stage 1 meaning they had two or more islet autoantibodies including mIAA and normal glucose tolerance
  • In each group, half of the people took a 7.5 mg daily capsule of oral insulin and half took a placebo capsule. 
    • Group 1 consisted of 389 participants. These participants were positive for mIAA, either ICA or GAD65, and IA-2 autoantibodies. They also had higher functioning beta cells.
    • Group 2 included 55 participants who had the same autoantibodies as Group 1. However, this group had lower functioning beta cells.
    • Groups 3 and 4 included 116 participants positive for the mIAA autoantibody, plus GAD or IA-2 autoantibodies.

Key Findings

  • Oral insulin was safe and well-tolerated in all groups.
  • In group 1, the main study group, (389 relatives) and group 3 & 4 (combined 116 relatives), oral insulin did not prevent or delay onset of T1D. 
  • In group 2 (55 relatives having lower insulin production), oral insulin delayed T1D onset by an average of 31 months.
  • The study further supports our understanding that not everyone develops T1D the same.

Next Steps

This study is an important step toward determining oral insulin’s role in delaying disease progression.  TrialNet is considering conducting new trials using oral insulin to delay disease progression; but more work needs to be done. 

Stay tuned:

Results of another important study, Exploring Immune Effects of Oral Insulin in Relatives at Risk for T1D, are expected later this year. This study is looking at how different doses and regimens of oral insulin effect immune response

In addition, two other prevention studies currently underway are testing the drugs Abatacept and Teplizumab to see if they can delay or prevent disease progression prior to diagnosis. TrialNet will also be launching new type 1 diabetes prevention trials and encourages all family members 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! 

Oral Insulin study participant resources are available here

If you are a current participant in the Immune Effects of Oral Insulin study and have questions about your study or the Oral Insulin study results, please contact your study team or