Type 1 diabetes is caused by an immune attack on insulin-producing beta cells of the pancreas that impairs their ability to make insulin to control blood glucose levels. When diabetes is diagnosed, the pancreas is usually still able to make some insulin, but not enough to meet the body's needs. Over time, continued immune attack further decreases insulin production until after one to two years it is very low or undetectable. When type 1 diabetes is diagnosed, treatments that stop the immune attack may preserve residual beta-cell function. This decreases the requirement for injected insulin and improves glucose control. However, so far, immune therapies have not been shown to prevent ongoing loss of beta-cell function. In this clinical trial, two safe immune therapies called abatacept and nasal insulin will be used together to test if the combination can better preserve the function of beta cells to make insulin after diagnosis. If this occurs, it will be relatively simple to develop this treatment for routine use in recently-diagnosed people and to test whether it prevents high-risk individuals progressing to need insulin injections. This trial will also provide research samples to improve our understanding of how type 1 diabetes develops and how abatacept and nasal insulin might affect this process. The new knowledge created from studying these samples will improve our ability to use abatacept and nasal insulin to preserve pancreas function in type 1 diabetes.
The goal of this clinical trial is to test whether the combination of two safe immune therapies called abatacept and nasal insulin can preserve pancreas function in recently-diagnosed type 1 diabetes. When type 1 diabetes is first diagnosed, the pancreas is still able to make small amounts of insulin, which helps control glucose levels. Preserving pancreas function can make glucose control easier and reduce the need to use injected insulin.~Participants will be asked to inject abatacept under their skin once per week and inhale nasal insulin or nasal placebo using a spray for 10 consecutive days initially and twice per week thereafter. The treatment period is for 48 weeks, with another 48-week follow-up period.