Teplizumab (TEIZEILD®) is indicated for adults and children aged 8 years and older with stage 2 type 1 diabetes (T1D) to delay progression to stage 3. T1D is a chronic autoimmune disease characterised by destruction of insulin-producing pancreatic beta cells. Stage 2 is defined by the presence of two or more autoantibodies and dysglycaemia in the absence of clinical symptoms. Teplizumab is a humanised monoclonal anti-CD3 antibody that reduces the autoreactive activity of CD4+ and CD8+ T cells, thereby preserving endogenous insulin secretion. Treatment is administered as a single 14-day intravenous infusion course. Teplizumab received marketing authorisation from the European Commission in early January 2026.

The efficacy and safety of teplizumab were investigated in a randomised, placebo-controlled, double-blind phase 2 trial (TN-10). In the primary analysis (n=76; 44 teplizumab, 32 placebo; median follow-up: 24.5 months), the median time to T1D diagnosis was 48.4 months with teplizumab versus 24.4 months with placebo (HR 0.41; 95% CI: 0.22–0.78; p<0.01). This finding was consistent across follow-up analyses with observation periods of up to 80.5 months. C-peptide levels, as a marker of endogenous insulin secretion, were significantly higher in the teplizumab group at a median follow-up of 30.3 months (1.94 vs 1.72 pmol/ml; p<0.01). Glucose levels were also significantly lower with teplizumab (164 vs 177 mg/dl; p<0.05), while HbA1c values showed no significant difference. Adverse events occurred in nearly all patients in the teplizumab group (112 events), predominantly haematological disorders (75%, mainly lymphopenia) and skin reactions (36%). Severe adverse events (grade 3) occurred primarily within the first 30 days; lymphopenia resolved in nearly all cases. No deaths were reported. The overall risk of bias of the TN-10 trial was rated as low.

Teplizumab represents the first disease-modifying therapy for stage 2 T1D and may constitute a relevant treatment option, particularly for children and adolescents in Austria. However, no studies directly comparing teplizumab with other therapies are currently available, and quality-of-life and long-term data are lacking. Additional challenges include structural barriers to identifying eligible patients, as no systematic screening programme for presymptomatic T1D is established in Austria, and outpatient administration over 14 consecutive days is currently not feasible in most Austrian centres. Treatment is associated with high costs (estimated 5-year incremental costs of approximately €169,975 per patient compared to standard care), and four international health economic analyses consistently indicate an unfavourable cost-effectiveness profile.