Minimal symptom expression achievement over time in generalized myasthenia gravis

Objectives: Minimal symptom expression (MSE), defined as myasthenia gravis (MG) activities of daily living profile (MGADL) score 0 or 1, has been recently used as an indicator of treatment goal in MG. However, no study has determined when MSE is achieved. The current study aimed to investigate the timing and incidence of MSE achievement in generalized MG patients.

Methods: Eighty-five patients with acetylcholine receptor antibody-positive generalized MG were included. They were followed-up maximum 3 years after starting immunotherapy, and we reviewed the MGADL score, prednisolone dose, and achievement of MSE and minimal manifestations (MM) or better status.

Results: MSE was achieved in 37.6, 45.2, 55.8, 60.3, and 57.1% of the patients at 3, 6, 12, 24, and 36 months after treatment, respectively. Most patients who achieved MSE showed MM or better status at any phase. In addition, more than 2 years after the starting treatment, about 80% of patients who achieved MSE showed MM or better status with an oral prednisolone dose of 5 mg/day or less (MM-5 mg). Noteworthy, during the early stage of treatment, the proportion of patients who achieved MSE was higher than that who achieved MM-5 mg.

Conclusion: From the early phases of immunotherapy, MSE is a good marker of therapeutic goal in patients with generalized MG.