GSE176055
Safety and preliminary efficacy of allogeneic bone marrow-derived multipotent mesenchymal stromal cells for systemic sclerosis: a single-centre, open-label, dose-escalation, proof-of-concept, phase 1/2 study
Background: Systemic sclerosis (SSc) is a chronic autoimmune disease. We tested the safety of a single intravenous injection of intrafamilial allogeneic bone marrow-derived mesenchymal stromal cells (BM-MSC) to treat severe SSc. Methods: We conducted the first prospective, monocentric, dose-escalation, phase I/II clinical trial investigating the feasibility and safety of a single allogeneic BM-MSC infusion in 20 severe SSc patients who were refractory or had a contraindication to conventional immunosuppressive therapy or autologous hematopoietic stem cell transplant. Patients were assigned to an infusion of either 1x10^6 BM-MSC/kg or 3x10^6 BM-MSC/kg obtained from 20 independent intrafamilial donors. Primary endpoint was the rate of grade = 3 Severe Adverse Events (SAE; NCI Common Terminology Criteria for Adverse Events (v5.0)) in the first 10 days post-BM-MSC infusion. Secondary endpoints included adequacy of BM-MSC production, medium-term SAE, as well as clinical and immunological response. Findings: No Grade 3 = SAE occurred in the first 10 days following MSC infusion in the 20 SSc patients. A significant improvement in modified Rodnan Skin Score (p<0.0001) was observed after BM-MSC infusion, which peaked at 3 months and was sustained for 1 year. No changes in health-related quality of life or pulmonary function were observed. CD8pos T-Cell and NK cell counts slightly increased after infusion (p<0.05) and two patients developed de novo donor-specific anti-HLA. Circulating TGF-ß level at baseline was significantly higher in non-responder compared to responder patients (p<0.05). A pattern of low IDO activity, CCL2 production, and HLA-DR expression in BM-MSC batches under in vitro stimulation by IFN-beta was associated with a lack of clinical response in recipient SSc patients. Interpretation: A single infusion of allogeneic BM-MSC transplant was safe in severe SSc patients and triggered short-term disease modifying effects. Clinical response was associated with both the recipients biological features and the functional properties of infused BM-MSC. Overall design: An aliquot of passage #1 BM-MSC derived from 17 healthy donors were collected prior to infusion in the recipient and cryopreserved analyzed for RNA sequencing.