Oral Insulin for Prevention of Diabetes in Relatives at Risk for Type 1 Diabetes Mellitus

Type 1 diabetes (T1D) is an autoimmune disease. This means that the immune system (the part of the body which helps fight infections) mistakenly attacks and destroys the cells that produce insulin (islet cells found in the pancreas). As these cells are destroyed, the body's ability to produce insulin decreases. There is evidence suggesting that repeated oral administration of an autoantigen (the same protein that the immune system is reacting to) may introduce a protective immunity and cause the immune system to stop its attack. An earlier, large scale study was done to see if oral insulin could delay or prevent the development of Type 1 diabetes in relatives at risk for developing Type 1 diabetes. The overall results showed that for the entire study population, oral insulin did not delay or prevent Type 1 diabetes. However, an analysis that was done after the conclusion of the trial suggested a potential beneficial effect in a subgroup of participants. The participants who seemed to benefit from oral insulin had higher levels of insulin autoantibodies which are directed against insulin itself ( called mIAA). The Type 1 Diabetes TrialNet study group will further explore the potential role of oral insulin to delay or prevent Type 1 diabetes in a similar group of people. The study will also include a secondary group of individuals at different levels of risk than those in the primary cohort to gather information for future studies.

Eligible participants will be randomized to receive either oral insulin (7.5 mg of recombinant human insulin crystals) or placebo daily. All participants randomized into this study will be seen at a study site for a follow-up evaluation, three and six months after randomization, and every six months thereafter. Participants will be contacted by phone between 6-monthly clinic visits to assess changes in diabetes status, medication compliance and adverse events. These phone contacts will occur approximately 3 months from the date of the participants previous clinic visit. At the study visits, participants will undergo assessments of their insulin production, immunologic status, and overall health. As the primary outcome measure, subjects will be followed until development of type 1 diabetes or the conclusion of the study. The trial is expected to last approximately 7-8 years or until the required amount of information is gathered.