Rapamycin Plus Vildagliptin to Recover β-Cell Function in Long-Standing Type 1 Diabetes: A Double-Blind, Randomized Trial

Abstract

Aim: The aim of this study was to investigate whether treatment with rapamycin plus vildagliptin restores β-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 β-cell function in patients with long-standing type 1 diabetes.

Trial registration: ClinicalTrials.gov NCT02803892.

Keywords: C-peptide; DPP-4 inhibitors; insulin antibody; long-standing type 1 diabetes; rapamycin; vildagliptin.