Use of Bone Marrow Stem Cells (MesenCell) for the Treatment of Patients With Chronic Graft-versus-host Disease

The purpose of this Phase I clinical trial is to evaluate the safety and potential treatment response of bone marrow-derived mesenchymal stem cells (MesenCell) in adult patients with moderate or severe chronic graft-versus-host disease (cGVHD) that is refractory to corticosteroid treatment. The main questions it seeks to answer are: * Is MesenCell infusion safe in patients with corticosteroid-refractory chronic graft-versus-host disease? * Can MesenCell treatment improve the clinical response and disease control in these patients? Participants will receive one to three intravenous infusions of MesenCell, according to the study protocol and be followed for 12 months after the last MesenCell infusion.

Inclusion Criteria: * Age from 18 to 70 years; * Male or female sex; * Patients after allogeneic hematopoietic stem cell transplantation (any donor or stem cell source); * Presenting with moderate or severe chronic Graft versus host Disease refractory to treatment with corticosteroids and calcineurin inhibitors; * Patients who agree to participate in this study and who sign the Informed Consent Form. Exclusion Criteria: * Patients with any concomitant clinical condition that, in the physician's opinion, contraindicates the infusion of bone marrow-containing stem cells; * Pregnancy; * Patients (or their legal guardians) who do not agree to participate in this study or who do not sign the Informed Consent Form; * Patients with recurrent malignant neoplasm.