Efficacy and Safety of T Cell‐Targeted Immunotherapy in Newly Diagnosed Type 1 Diabetes: A Systematic Review and Meta‐Analysis

AIMS: To assess the efficacy and safety of T cell-targeted immunotherapy in patients with newly diagnosed type 1 diabetes (T1D). MATERIALS AND METHODS: A comprehensive search of PubMed, Embase, CENTRAL, Web of Science, Scopus and ClinicalTrials.gov up to 6 March 2026 was performed. Randomised controlled trials comparing T cell-targeted immunotherapeutic agents with placebo in patients with newly diagnosed T1D were included. The primary outcome was change in the area under the curve (AUC) of C-peptide, whereas the secondary outcomes included change in glycated haemoglobin (HbA1c) levels, change in daily insulin dose, and adverse events. RESULTS: Twenty-one trials involving 1970 participants were included in this study. Compared with the control treatment, T cell-targeted immunotherapy significantly increased the C-peptide AUC, with SMDs of 0.38 (95% CI: 0.19-0.57; p < 0.001) at 6 months, 0.41 (95% CI: 0.12-0.69; p = 0.005) at 12 months, 0.48 (95% CI: 0.32-0.65; p < 0.001) at 18 months, and 0.49 (95% CI: 0.32-0.65; p < 0.001) at 24 months. Consistently, this therapy also reduced HbA1c levels and daily insulin dose at all time points (all p < 0.05). Subgroups with younger age (< 18 years), worse baseline metabolic status, and single-blind or open-label design showed greater efficacy in the early phase of therapy. The risks of total and serious adverse events were comparable between the intervention and control groups. CONCLUSIONS: T cell-targeted immunotherapy provides sustained preservation of β-cell function and improvements in HbA1c levels and insulin requirements for at least 24 months in patients with newly diagnosed T1D.