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

The TrialNet (TN20) study was a two-arm, multi-center, randomized, open-labeled clinical trial designed to assess the effects of varying doses and schedules of oral insulin on immunological and metabolic markers in relatives at risk for type 1 diabetes (T1D).

Participants were from the TrialNet Natural History/Pathway to Prevention (TN01) study, had a relative with T1D, and were positive for insulin autoantibodies and at least one other autoantibody. All participants received an active treatment of recombinant insulin in capsules of either 67.5 mg daily or 500 mg every other week. Participants visited the study site up to 11 times over one year for blood tests and other study procedures. During the beginning treatment phase, there were two visits one month apart for those given the 67.5 mg dose, and three visits two weeks apart to titrate the dose for those in the 500 mg treatment group. There were three additional treatment visits at months 2, 3, and 6, as well as four additional visits for follow-up at months 7, 8, 9, and 12. The primary outcome was the change in immune function as assessed by change in level or quality of T-lymphocyte or autoantibody biomarkers measured between 13 and 26 weeks compared to the baseline.