What type 1 diabetes endotype is most suitable for anti-CD3 antibodies prevention trials?

Type 1 diabetes (T1D) is a heterogeneous autoimmune disease with multiple endotypes, each demonstrating distinct clinical and immunological characteristics. Teplizumab, an anti-CD3 monoclonal antibody, has emerged as a promising immunomodulatory therapy capable of delaying the progression of T1D in individuals with stage 2 disease. However, variability in therapeutic response suggests that certain endotypes may derive greater benefit from treatment. This review evaluates the suitability of different T1D endotypes (T1DE) for teplizumab prevention trials, with a particular focus on early-onset T1DE1 and T1DE2. Clinical trials demonstrate that individuals under 15 years of age, who demonstrate the highest immune activity, marked by aggressive T-cell infiltration and rapid pancreatic β-cell destruction, experience the most significant delay in disease progression following teplizumab treatment, highlighting the importance of early intervention. Furthermore, shifting individuals from the rapidly progressing T1DE1 trajectory to the more gradual T1DE2 course may extend functional insulin production and improve long-term metabolic outcomes. This paper underscores the need for expanded endotype-specific prevention trials and optimised screening protocols to identify high-risk individuals at the earliest stage. Future research should explore teplizumab's efficacy in younger populations and refine predictive biomarkers to enhance personalised intervention strategies in T1D management.