Subcutaneous immunoglobulin in myasthenia gravis exacerbation: A prospective, open-label trial

To investigate the efficacy, tolerability, and safety of subcutaneous immunoglobulin (SCIg) in patients with mild to moderate myasthenia gravis (MG) exacerbation. We performed a prospective, open-label, phase 3 trial in patients with MG aged 18 years or older and mild to moderate worsening (transition from Myasthenia Gravis Foundation of America class I to II/III or class II to III), treated with SCIg (2 g/kg), self-administered over 4 weeks. The primary endpoint was change in quantitative MG (QMG) score from baseline to study end at 6 weeks. Secondary endpoints included change in manual muscle testing (MMT), MG activities of daily living (MG-ADL), and MG composite (MGC) scores, as well as occurrence of adverse events, and tolerability as assessed via Treatment Satisfaction Questionnaire for Medication (TSQM). Twenty-two of 23 patients completed the study. QMG score decreased from 14.9 ± 4.1 to 9.8 ± 5.6 ( < 0.0001), MMT score decreased from 16.8 ± 9.5 to 5.2 ± 4.5 ( < 0.0001), MG-ADL score decreased from 9.5 ± 3.0 to 4.6 ± 3.0 ( < 0.0001), and MGC score decreased from 17.4 ± 5.0 to 5.6 ± 4.5 ( < 0.0001). Satisfaction by TSQM was high (79.6 ± 15.6%). Common adverse events included headache and injection site reactions. No serious adverse events occurred. SCIg is well-tolerated, safe, and effective in mild to moderate MG exacerbation. Comparative safety and efficacy must be established with randomized controlled trials. This study provides Class IV evidence that in patients with mild to moderate MG exacerbation, SCIg is safe and effective in reducing MG disability measures.