The opportunities and challenges of the disease-modifying immunotherapy for type 1 diabetes: A systematic review and meta-analysis

There are multiple disease-modifying immunotherapies showing the potential of preventing or delaying the progression of type 1 diabetes (T1D). We designed and performed this systematic review and meta-analysis to gain an overview of what a role immunotherapy plays in the treatment of T1D. We searched PubMed, Embase and Cochrane Central Register of Controlled Trials (CENTRAL) from inception to December 2023. We included clinical trials of immunotherapy conducted in patients with T1D that reported the incidence of hypoglycemia or changes from baseline in at least one of following outcomes: 2 h and 4 h mixed-meal-stimulated C-peptide area under the curve (AUC), fasting C-peptide, daily insulin dosage, glycated hemoglobin (HbA1c) and fasting plasma glucose (FPG). The results were computed as the weighted mean differences (WMDs) or odds ratios (ORs) and 95% confidence intervals (CIs) in random-effect model. In all, 34 clinical trials were included. When compared with control groups, 2 h C-peptide AUC was marginally higher in patient treated with nonantigen-based immunotherapies (WMD, 0.04nmol/L, 95% CI, 0.00-0.09 nmol/L, P=0.05), which was mainly driven by the effects of T cell-targeted therapy. A greater preservation in 4 h C-peptide AUC was observed in patients with nonantigen-based immunotherapies (WMD, 0.10nmol/L, 95% CI, 0.04-0.16 nmol/L, P=0.0007), which was mainly driven by the effects of tumor necrosis factor α (TNF-α) inhibitor and T cell-targeted therapy. After excluding small-sample trials, less daily insulin dosage was observed in patient treated with nonantigen-based immunotherapies when compared with control groups (WMD, -0.07units/kg/day, 95% CI, -0.11 to -0.03units/kg/day, P=0.0004). The use of antigen-based immunotherapies was also associated with a lower daily insulin dosage versus control groups (WMD, -0.11units/kg/day, 95% CI, -0.23 to -0.00units/kg/day, P=0.05). However, changes of HbA1c or FPG were comparable between nonantigen-based immunotherapies or antigen-based immunotherapies and control groups. The risk of hypoglycemia was not increased in patients treated with nonantigen-based immunotherapies or patients treated with antigen-based immunotherapies when compared with control groups. In conclusion, nonantigen-based immunotherapies were associated with a preservation of 2 h and 4 h C-peptide AUC in patients with T1D when compared with the controls, which was mainly driven by the effects of TNF-a inhibitor and T cell-targeted therapy. Both nonantigen-based immunotherapies and antigen-based immunotherapies tended to reduce the daily insulin dosage in patients with T1D when compared with the controls. However, they did not contribute to a substantial improvement in HbA1c or FPG. Both nonantigen-based immunotherapies and antigen-based immunotherapies were well tolerated with not increased risk of hypoglycemia in patients with T1D.