Long-term efficacy and safety of leflunomide combined with low-dose prednisone in treatment of myasthenia gravis: a retrospective study

Background Leflunomide and low-dose prednisone (0.25 mg/kg/day) (LEF + Pred) rapidly improved the clinical symptoms of myasthenia gravis (MG) patients. Here, we aimed to analyze the long-term efficacy and safety of LEF + Pred in MG patients. Methods This retrospective cohort study enrolled MG patients treated with LEF + Pred in our center between 2012 and 2020. We reviewed all the MG patients continuously treated with LEF + Pred for more than 1 year. MG activities of daily living (MG-ADL) profile score and quantitative MG scale (QMG) score in each clinical follow-up visits were collected for the efficacy analysis. The laboratory testing results of MG patients, the relevant chief complain and physical examination results in each follow-up visits were collected for the safety evaluation. Results In total, 103 patients were examined. Effective treatment was achieved in 58.3% of patients after 1 month and in 88.4% after 12 months. Overall, 63 patients (61.2%) exhibited only minimal manifestations after 12 months of treatment. The average MG-ADL score decreased from 6.0 to 1.0, while the average QMG score decreased from 10.0 to 4.0. The decrease in MG-ADL and QMG scores of patients with generalized MG was more pronounced than those of the ocular MG patients. Patients with MG who had a thymectomy had a smaller decrease in MG-ADL and QMG scores than those who did not have a thymectomy. Sixteen adverse effects associated with LEF + Pred were observed; none was severe. Conclusions Long-term LEF + Pred therapy could considerably improve clinical symptoms in MG patients while being well tolerated with just few side effects.