Subcutaneous Immunoglobulin for Myasthenia Gravis

Myasthenia gravis (MG) is an autoimmune neuromuscular condition which can cause fatigable weakness of skeletal muscles including bulbar, ocular, limb, axial and respiratory muscles. Symptoms range from mild, transient double vision and ptosis to severe, life threatening diffuse weakness, and treatments which are immunosuppressive or immunomodulatory have been shown to improve outcome in MG. This includes 10% intravenous immunoglobulin (IVIG), which has previous been shown by our group to improve strength at 2 and 4 weeks in patients with MG. Due to delay in the onset of many immunosuppressives and potential side effects from steroids and other immunosuppressive medications, IVIG is also used in clinical practice as bridging of maintenance therapy until other therapies take effect or the patient stabilizes. In addition, there have been other studies suggesting that 20% subcutaneous immunoglobuin (SCIG) can be helpful to improve strength in patients with MG over a relatively short period of time (6 weeks). Some of these studies are ongoing and are further evaluating the ability of IVIG and SCIG to stabilize or improve strength IVIG in patients with MG, however, there is no current published study evaluating different administration routes of immunoglobulin (IVIG and SCIG) in patients with MG over a longer 6 month follow-up period. The current study aims to be the first to evaluate 20% Cuvitru SCIG formulation in patients with neuromuscular conditions including MG. The study aim is to evaluate the safety and efficacy of 6 months of 20% SCIG Cuvitru treatment vs three months of 10% IVIG "pre-treatment" followed by 3 months of 20% SCIG Cuvitru treatment. The study will also be the first to use the myasthenia gravis impairment index (MGII) as primary outcome in conjunction with standard MG outcomes.