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

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.