Immunomodulation is used when rapid improvement is required, i.e., MG exacerbation,7,–,11 preoperative optimization of strength prior to thymectomy,12 and in patients who cannot tolerate or do not respond to immunosuppressive medications.5,10,11
The benefits of immunomodulation with PLEX and IVIg have been demonstrated in several studies.10,11,13,14 A recent double-blind, placebo-controlled, randomized clinical trial demonstrated the efficacy of IVIg in patients with MG and worsening weakness with greater response in patients with more severe MG.7
While both IVIg and PLEX appear to be useful in worsening MG, there is insufficient evidence available as to which treatment is more effective. An unmasked study compared a short course of PLEX with 2 different doses of IVIg and showed no significant difference between treatments.15 Smaller studies have suggested PLEX may be superior and faster acting than IVIg.16,17 The small numbers, unmasked assessments, lack of standard treatment protocols, and lack of standardized assessments raise questions about the conclusions of these studies. Since immunomodulation treatments are costly, it is important to determine whether the treatments are comparable to help guide therapy of patients with MG.
We carried out a randomized, evaluator-masked study in patients requiring immunomodulation for moderate to severe MG to determine whether IVIg was comparable to PLEX.
This study provides Class I evidence that IVIg and PLEX have comparable efficacy and are equally tolerated in adult patients with moderate to severe MG within 2 weeks of treatment.