Rapamycin Plus Vildagliptin To Recover Beta-Cell Function In Long-Standing Type 1 Diabetes: A Double-Blind, Randomized Trial

Aim: The aim of this study was to investigate whether treatment with rapamycin plus vildagliptin restores beta-cell function in patients with long-standing type 1 diabetes.Methods: A phase 2, single-center, randomized, double-blind, placebo-controlled study was conducted in long-standing type 1 diabetes patients randomly assigned (1:1:1) to 4 weeks of rapamycin (group 2), 4 weeks of rapamycin plus 12 weeks of vildagliptin (group 3), or double placebo (group 1). The primary outcome was the proportion of participants with a positive response to the Mixed-Meal Tolerance Test (C-peptide at 90 minutes>0.2 nmol/L) at weeks 4 and 12. Secondary end points included insulin requirement, standard measures of glycemic control, and hormonal and immunological profile.Results: Fifty-five patients were randomly assigned to group 1 (n=18), group 2 (n=19), or group 3 (n=18). No patient in any group showed a positive C-peptide response, and there was no significant difference at 4 and 12 weeks for the primary outcome. At 4 weeks, insulin requirement decreased from 0.54 to 0.48 U/kg/day in group 2 (P=.013), from 0.59 to 0.51 U/kg/day in group 3 (P<.001), whereas it did not change in group 1. At 12 weeks, glycated hemoglobin significantly decreased both in group 2 (from 7.3% [56 mmol/mol] to 7% [53 mmol/mol]; P=.045] and in group 3 (from 7.2% [55.5 mmol/mol] to 6.9% [52 mmol/mol]; P=.001]. Rapamycin treatment was associated with a decrease in insulin antibody titer and changes in hormonal/immunological profile.Conclusions: Rapamycin reduced insulin requirement, but did not restore beta-cell function in patients with long-standing type 1 diabetes.