Randomised, double-blind, placebo-controlled study of tacrolimus in myasthenia gravis.

OBJECTIVES: To evaluate the ability of tacrolimus to reduce the corticosteroid dose in patients with myasthenia gravis (MG) and the drug's safety in a double-blind, placebo-controlled, parallel group study. METHODS: Patients being treated with oral prednisolone at doses equivalent to 10-20 mg/day, and with stable symptoms, were randomised to tacrolimus or placebo in a 28-week double-blind study. The dose of corticosteroid was tapered with the procedures specified in the protocol. The primary efficacy endpoint was the mean daily prednisolone dose given in the last 12 weeks of the study. RESULTS: Eighty patients received the study drug (40 patients in each group) and were included in the full analysis set. In the full analysis set, there was no significant difference in the primary efficacy endpoint between the two groups (p = 0.078). However, some secondary analyses suggested the steroid-sparing effect of tacrolimus. Tacrolimus was well tolerated, and no safety concerns were noted. CONCLUSIONS: This study suggests that tacrolimus has a potential advantage as a steroid-sparing agent in the treatment of MG patients. CLINICAL TRIAL REGISTRATION NUMBER: NCT00309088. Name of the trial registry: FK506 Phase 3 STUDY: A STUDY for Steroid Non-Resistant MG Patients.