Efficacy of low-dose FK506 in the treatment of Myasthenia gravis--a randomized pilot study.

To determine the efficacy of low-dose FK506 in the treatment of myasthenia gravis (MG), untreated de novo patients were randomly selected to receive treatment with (n = 18) or without (n = 16) FK506, and were evaluated for 1 year after treatment with limitation of daily dose of prednisolone. Low-dose FK506 reduced the duration of early-phase therapy in hospital (p < 0.05) and the need for combined therapy with plasmapheresis and high-dose intravenous methylprednisolone or high-dose intravenous methylprednisolone alone (p < 0.05). It also reduced the daily dose of prednisolone (p < 0.05) required to maintain minimal manifestations of MGFA postintervention status. None of the patients exhibited significant side effects up to 1 year after treatment. These findings suggest that low-dose FK506 is safe and efficacious for the treatment of de novo MG patients.