Long-term efficacy and safety of tacrolimus in young children with myasthenia gravis.

OBJECTIVE: This study was performed to evaluate the efficacy and long-term safety of tacrolimus for young children with myasthenia gravis (MG).

METHODS: Children with corticosteroids (CSs)-ineffective, CSs-dependent or CSs-intolerable MG treated with tacrolimus for at least one year were recruited. The Myasthenia Gravis Foundation of America (MGFA) clinical classification and MGFA post-intervention status (MGFA-PIS) were used to evaluate before tacrolimus administration and at the last visit, respectively. MG Activities of Daily Living (MG-ADL) score and the dose of prednisone were recorded. Patients were divided into responders and poor responders based on changes in MG-ADL score to investigate the factors that affected tacrolimus efficacy. Unfavorable events were recorded.

RESULTS: Twenty-one patients with MG were enrolled. The median age of starting tacrolimus was 8.7 (range 2.2-15.1) years old. At the last visit, 15 patients (71.4%) achieved minimal manifestation (MM) or better status. The symptoms evaluated by MG-ADL improved significantly one month after initiating tacrolimus (p＜0.05) and the dose of prednisone decreased significantly three months later (p＜0.05), and it continued to improve throughout the study. Thirteen patients (61.9%) were ultimately weaned off prednisone. Compared with 16 responders, 5 poor responders had lower MG-ADL scores. MG-ADL score was the only clinical factor of tacrolimus efficacy. Intraocular pressure and transient urine microprotein were present in one patient.

CONCLUSION: A course of tacrolimus of more than one year was effective and well-tolerated in young children with MG, and tacrolimus improved MG symptoms and reduced the dose and adverse events of oral prednisone.