Treatment of myasthenia gravis exacerbation with intravenous immunoglobulin: a randomized double-blind clinical trial

Abstract

Background: The optimal dose of intravenous immunoglobulin (IVIG) in acute exacerbation of myasthenia gravis remains unknown. Increasing the treatment duration might provide added efficacy.

Objective: To determine the optimal dose of IVIG for treating myasthenia gravis exacerbation.

Design: Randomized double-blind placebo-controlled multicenter trial designed to demonstrate superiority of the 2 g/kg dose over the 1 g/kg dose of IVIG, conducted between November 13, 1996, and October 26, 2002.

Participants: One hundred seventy-three patients aged 15 to 85 years with acute exacerbation of myasthenia gravis.

Intervention: Participants were randomly assigned to receive 1 g/kg of IVIG on day 1 and placebo on day 2 (group 1) vs 1 g/kg of IVIG on 2 consecutive days (group 2).

Main outcome measure: Improvement in the myasthenic muscular score after 2 weeks.

Results: The mean improvements in the myasthenic muscular scores after 2 weeks were 15.49 points (95% confidence interval, 12.09-18.90 points) in group 1 and 19.33 points (95% confidence interval, 15.82-22.85 points) in group 2. However, the difference between the 2 groups was not significant (effect size, 3.84 [95% confidence interval, -1.03 to 8.71]; P = .12).

Conclusion: This trial found no significant superiority of 2 g/kg over 1 g/kg of IVIG in the treatment of myasthenia gravis exacerbation.