P.035 Autologous hematopoietic stem cell transplant for the treatment of refractory myasthenia gravis with anti-muscle specific kinase antibodies

Abstract

Background: Several case series describe patients with refractory acetylcholine receptor antibody-positive (AChR) myasthenia gravis (MG) treated with hematopoietic stem cell transplant (HSCT). In this report, we describe four patients with anti-muscle-specific kinase (MuSK)MG treated with HSCT. Methods: We reviewed the records of all patients undergoing HSCT for MG in the Alberta Blood and Bone Marrow Transplant Program and identified 4 patients with anti-MuSK MG. Results: All 4 patients had severe disease (Myasthenia Gravis Foundation of America score IVb-V) and were refractory to multiple treatments, including rituximab. 3 patients improved with no clinical manifestations or mild symptoms and remained as such for 2, 3.5, and 5.5 years. In these 3 patients, adverse events ranged from treatable infections and transient dyspnea to persistent fatigue and premature menopause. The average worst Myasthenia Gravis Activities of Daily Living (MG-ADL) scores improved from 14.7 before to 0.3 after HSCT while their mean worst Myasthenia Gravis Quality of Life Questionnaire (MG-QoL15) scores improved from 26.7 to 0. The fourth patient developed pneumonia and passed away from respiratory failure 8 weeks post-transplant. Conclusions: In patients with severe refractory anti-MuSK MG, it may be reasonable to consider HSCT but with an appreciation of the associated risks.