PE vs. IVIG for Myasthenic Exacerbation

Source: Gajdos P, et al. Clinical Trial of plasma exchange and high-dose intravenous immunoglobulin in myasthenia gravis. Ann Neurol 1997;41:789-796.

This is the first study to compare the safety and efficacy of plasma exchange (PE) vs. intravenous immunoglobulin (IVIG) to treat myasthenic exacerbation. Eighty-seven myasthenic patients with recent exacerbation, defined as the appearance within the past month of dysphagia, acute respiratory failure, or weakness with discontinuation of activities, were randomized to receive either PE (n = 41) or IVIG (n = 46). PE was given as three exchanges of 1.5 volumes every other day, and IVIG was given as 0.4 g/kg daily for three or five days (n = 23 in each subgroup).

PE and IVIG groups showed comparable end points of myasthenic muscular score improvement between randomization and day 15. Secondary end points, including time to improvement (2 days) and acetylcholine receptor (AchR) antibody titer decrease between days 0 and 15 (mean, 13.8% and 16.8%, respectively) were also analogous. The PE group suffered more adverse events (14 adverse events in 9 patients vs 1 adverse event in the IVIG group), and PE was discontinued in two as a result. Inexplicably, the five-day IVIG treatment group improved their muscle score later than the three-day IVIG treatment group (improvement significant on day 6 compared to day 2, respectively, in the subgroups).

Although neither treatment was substantially better than the other, the simplicity of IVIG argues in its favor. Larger studies will be necessary to confirm these findings and define whether either treatment provides more significant improvement with fewer complications. —mr