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

OBJECTIVE: To investigate the efficacy, tolerability, and safety of subcutaneous immunoglobulin (SCIg) in patients with mild to moderate myasthenia gravis (MG) exacerbation.

METHODS: 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).

RESULTS: Twenty-two of 23 patients completed the study. QMG score decreased from 14.9 ± 4.1 to 9.8 ± 5.6 ( p < 0.0001), MMT score decreased from 16.8 ± 9.5 to 5.2 ± 4.5 ( p < 0.0001), MG-ADL score decreased from 9.5 ± 3.0 to 4.6 ± 3.0 ( p < 0.0001), and MGC score decreased from 17.4 ± 5.0 to 5.6 ± 4.5 ( p < 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.

CONCLUSIONS: SCIg is well-tolerated, safe, and effective in mild to moderate MG exacerbation. Comparative safety and efficacy must be established with randomized controlled trials.

CLASSIFICATION OF EVIDENCE: 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.