Umbilical Cord Mesenchymal Stromal Cell Secretome for Moderate Rheumatoid Arthritis: A Randomized Double-Blind Placebo-Controlled Trial

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by persistent synovial inflammation, progressive joint destruction, pain, and functional disability. Although conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) are the standard treatment, many patients continue to have active disease despite therapy. Umbilical cord-derived mesenchymal stromal cell (UC-MSC) secretome contains bioactive molecules with immunomodulatory and anti-inflammatory properties that may improve clinical outcomes. This randomized, double-blind, placebo-controlled trial evaluates the efficacy and safety of intramuscular UC-MSC secretome as an adjunct to standard csDMARD therapy in patients with moderate rheumatoid arthritis. Clinical response, inflammatory biomarkers, and adverse events are evaluated throughout the study.

Inclusion Criteria: * -Adults aged 18 to 60 years. * Diagnosis of rheumatoid arthritis according to the 2010 ACR/EULAR Classification Criteria. * Moderate disease activity (DAS28-CRP \>3.2 and ≤5.1). * Receiving stable conventional synthetic disease-modifying antirheumatic drug (csDMARD) therapy for at least 3 months before enrollment. * Stable dose of corticosteroids and/or NSAIDs for at least 4 weeks before enrollment, if applicable. * Willing and able to provide written informed consent. Exclusion Criteria: * Other autoimmune rheumatic diseases or overlap syndromes. * Active tuberculosis or other severe active infections. * Active hepatitis B, hepatitis C, or HIV infection. * History of malignancy. * Severe renal impairment or severe hepatic dysfunction. * Uncontrolled diabetes mellitus or uncontrolled cardiovascular disease. * Pregnancy or breastfeeding. * Known hypersensitivity to the study intervention or its components. * Participation in another interventional clinical trial within the previous 3 months.