Allogeneic bone marrow derived clonal mesenchymal stromal cells in refractory rheumatoid arthritis: a pilot study.

AIMS: This phase I trial assessed the safety and potential efficacy of monthly 3 dose intravenous infusion of allogeneic bone marrow-derived clonal mesenchymal stromal cells (BM-cMSCs) in refractory rheumatoid arthritis (RA) patients over 24 weeks. PATIENTS & METHODS: Six patients with refractory RA received BM-cMSC infusions at one-month intervals over a 24-week period. Safety outcomes included adverse events (AEs) and serious adverse events (SAEs). Clinical efficacy was assessed using the Visual Analog Scale (VAS), Simple and Clinical Disease Activity Indices (SDAI/CDAI), Health Assessment Questionnaire (HAQ), and American College of Rheumatology (ACR) response criteria. Serological makers including: erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), IL-10, IL-17, TNF-α, and Treg/Th17 ratios were measured. RESULTS: BM-cMSC infusions were well-tolerated, with no SAEs reported. VAS scores improved in three patients, with two achieving sustained pain relief and quality-of-life enhancement. Four patients met ACR20 at week 16, while SDAI and CDAI scores indicated disease activity reduction in three patients. Anti-CCP and RF levels showed variable responses, with some increases not consistently correlating with clinical outcomes. Serological biomarkers showed mixed results; IL-10 increased in five patients, while pro-inflammatory markers TNF-α and IL-17 decreased in the same individuals. CONCLUSIONS: BM-cMSC therapy demonstrated a favorable safety profile and potential efficacy in managing refractory RA. While preliminary results are promising, further studies with larger cohorts and long-term follow-up are needed to validate these findings and optimize therapeutic strategies. CLINICAL TRIAL REGISTRATION: IRCT20080728001031N29.