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 T1D in relatives at risk for developing T1D. The overall results showed that for the entire study population, oral insulin did not delay or prevent T1D.

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 were directed against insulin itself (called mIAA). Eligible participants were randomized to receive either oral insulin (7.5 mg of recombinant human insulin crystals) or placebo daily.

All participants randomized into TrialNet 07 were seen at a study site for a follow-up evaluation, three and six months after randomization, and every six months thereafter. Participants were contacted by phone between six monthly clinic visits to assess changes in diabetes status, medication compliance, and adverse events. These phone contacts occurred approximately three months from the date of the previous clinic visit. At the study visits, participants underwent assessments of their insulin production, immunologic status, and overall health.