This invention applies to the field of medicine, namely to endocrinology, and intended for the treatment of type 1 diabetes mellitus.The invention proposes a combination, containing a Dipeptidyl peptidase-4 (DPP-4) inhibitors, a proton pump inhibitors (PPI), and gamma-aminobutyric acid or a gamma-aminobutyric acid receptor agonists. This unique combination of medications and specific dosage of drugs leads to the regeneration (recovery) of the β-cells of the pancreas, which is presented by a dramatic reduction of insulin requirements up to a total insulin discontinuation in some persons.