Efficacy of allogeneic mesenchymal stem cell transplantation in patients with drug-resistant polymyositis and dermatomyositis

Objective To assess the safety and clinical efficacy of allogeneic mesenchymal stem cell transplantation (MSCT) in a small-scale pilot study with 10 patients with drug-resistant polymyositis (PM) or dermatomyositis (DM). Methods A single-arm trial involving 10 patients with DM/PM who were either refractory to standard treatment, or had severe systemic involvement. All patients consented and underwent allogeneic MSCT. Clinical and laboratory manifestations were compared before and after MSCT. Results Improvements were seen in serum creatine kinase (CK), CK-MB, patient global assessment by visual analogue scale and muscle strength by manual muscle test in all patients, as well as improvement in interstitial lung disease in selected patients. Improvement in chronic non-healing skin ulcers was noted in one patient. Clinical responses were also seen in patients undergoing a second MSCT for recurrence of disease. Conclusion MSCT appears safe and effective in drug-resistant patients with DM/PM. Larger-scale studies including a control group receiving standard treatment are needed to assess the long-term efficacy of allogeneic MSCT in refractory patients with DM/PM.