Five-year follow-up with low-dose tacrolimus in patients with myasthenia gravis

Myasthenia gravis (MG) is an antibody-mediated autoimmune disease of the neuromuscular junction, and prednisolone (PSL) and immunosuppressive drugs are available for treatment. Tacrolimus, a macrolide that suppresses the immune system, is used as a second-line treatment for MG. There have been several reports of the effects of tacrolimus over a few years of follow-up. Here, we report data from 9 patients with steroid-dependent generalized MG treated with low-dose tacrolimus (2-3 mg/day) for 5 years. Following treatment with tacrolimus, mean MG-activities of daily living score improved from 4.6 at baseline to 3.3 at 5 years after initiation of treatment. Mean dose of PSL could also be reduced, from 24.0 mg/day at baseline to 10.2 mg/day at 5 years, although there were no cases of total withdrawal of PSL. By contrast, 5 of the 9 patients experienced exacerbation of symptoms and transient increases in PSL dose during the 5-year period. Tacrolimus is an important option for treatment of MG; however, careful management is needed for long-term treatment with this drug.