The Deterrence of Rapid Metabolic Decline within 3 Months after Teplizumab Treatment in Individuals at High Risk for Type 1 Diabetes

Endpoints that provide an early identification of treatment effects are needed to implement type 1 diabetes prevention trials more efficiently. To this end, we assessed whether metabolic endpoints can be used to detect a teplizumab effect on rapid β-cell decline within 3 months after treatment in high-risk individuals in the TrialNet teplizumab trial. Glucose and C-peptide response curves (GCRCs) were constructed by plotting mean glucose and C-peptide values from 2-hour oral glucose tolerance tests on a 2-dimensional grid. Groups were compared visually for changes in GCRC shape and movement. GCRC changes reflected marked metabolic deterioration in the placebo group within 3 months of randomization. By 6 months, GCRCs resembled typical GCRCs at diagnosis. In contrast, GCRC changes in the teplizumab group suggested metabolic improvement. Quantitative comparisons, including two novel metabolic endpoints that indicate GCRC changes, the Within Quadrant Endpoint (WQE) and the Ordinal Directional Endpoint (ODE), were consistent with visual impressions of an appreciable treatment effect at 3 and 6-month timepoints. In conclusion, an analytic approach combining visual evidence with novel endpoints, demonstrated that Teplizumab delays rapid metabolic decline, and improves the metabolic state within 3 months after treatment; this effect extends for at least 6 months.