Efficacy of tacrolimus therapy for patients with childhood-onset myasthenia gravis

Abstract

  Objective: To evaluate the efficacy of tacrolimus therapy for patients with childhood-onset myasthenia gravis (MG). Methods: We retrospectively evaluated tacrolimus therapy in 5 patients with childhood-onset MG from the Saitama Children's Medical Center between January 2012 and May 2020. We collected patients' background characteristics and clinical manifestations. We also evaluated changes in MG activity of daily living score, MG composite score, and anti-acetylcholine receptor antibody every 1 to 3 months for 1 year after tacrolimus commencement. Results: Five patients (1 male) were treated with tacrolimus : ocular type (n=2) and generalized type (n=3). The median age at tacrolimus commencement was 3.8 (2.3-9.0) years. The initial tacrolimus doses were 0.05 (0.04-0.05) mg/kg/day. The duration between tacrolimus commencement and response was 30 (9-67) days. In all patients, MG activity of daily living score and MG composite score decreased at 3 months after tacrolimus commencement. Two patients had pharmacologic remission, two had minimal manifestations, and one had improved at the last visit. Patients who had pharmacological remission and minimal manifestations were treated with tacrolimus within 10 months of onset. One patient with improvement was treated with tacrolimus at 55 months after onset. Conclusions: Our findings suggest we should evaluate the tacrolimus efficacy for patients with childhood-onset MG at 3 months after commencement. Patients with a short treatment lag may have better outcomes.