Long-term treatment of steroid-dependent myasthenia gravis patients with low-dose tacrolimus

Objective To examine the long-term effects of tacrolimus in steroid-dependent myasthenia gravis (MG) patients. Patients and Methods We administered tacrolimus at 3 mg/day to 10 generalized MG patients presented with clinical worsening by a reduction in dose of prednisolone. The effects of tacrolimus were assessed by using the MG activities of daily living (MG-ADL) profile and the post-intervention status criteria provided by the Myasthenia Gravis Foundation of America (PSC-MGFA). Results Seven patients were able to use tacrolimus without serious adverse effects for 1.0-5.1 years ( mean 3.1 years). Further, its administration improved myasthenic symptoms to the level of pharmacologic remission or minimal manifestations of PSC-MGFA in 5 patients and made it possible to discontinue prednisolone administration in 4 of those 5. However, despite improvements caused by tacrolimus, the reduction in dose of prednisolone caused worsening of symptoms in another 2 patients. In addition, blood trough levels of tacrolimus lower than the recommended range were effective to maintain long-term improvements in 2 patients. Conclusions Administration of tacrolimus induced long-term improvements and enabled replacement of prednisolone in patients with intractable steroid-dependent MG.