Clinical trial of plasma exchange and high‐dose intravenous immunoglobulin in myasthenia gravis

Abstract We have conducted a trial to randomly assess the efficacy and tolerance of intravenous immunoglobulin (IVIg) or plasma exchage (PE) in myasthenia gravis (MG) exacerbation and to compare two doses of IVIg. Eighty‐seven patients with MG exacerbation were randomized to receive either three PE (n = 41), or IVIg (n = 46) 0.4 gm/kg daily further allocated to 3 (n = 23) or 5 days (n = 23). The main end point was the variation of a myasthenic muscular score (MSS) between randomization and day 15. The MSS variation was similar in both groups (median value, +18 in the PE group and +15.5 in the IVIg group; p = 0.65). Similar efficacy, although slightly reduced in the 5‐day group was observed with both IVIg schedules. The tolerance of IVIg was better than that of PE with a total of 14 side effects observed in 9 patients, 8 in the PE group and 1 in the IVIg group ( p = 0.01). Although our trial failed to show a pronounced difference in the efficacy of both treatments, it exhibited a very limited risk for IVIg. IVIg is an alternative for the treatment of myasthenic crisis. The small sample sizes in our trial, however, could explain why a difference in efficacy was not observed. Further studies are needed to compare PE with IVIg and to determine the optimal dosage of IVIg.