Comparison of Plasmapheresis and Intravenous Immunoglobulin as Maintenance Therapies for Juvenile Myasthenia Gravis
Liew WK, Powell CA, Sloan SR, et al
JAMA Neurol. 2014;71:575-580
Study Summary
Juvenile myasthenia gravis (MG) is an autoimmune condition of low prevalence. Randomized clinical trials in adults with MG suggest that plasmapheresis (PLEX) is comparable to intravenous immunoglobulin (IVIG), with similar efficacies, durations of benefit, and safety. Whether PLEX is as effective as IVIG for maintenance therapy of juvenile MG was previously unknown.
This retrospective analysis compared PLEX and IVIG as maintenance therapy in 54 children and adolescents with juvenile MG. The patients were seen over a 33-year period in a specialized neuromuscular clinic and electromyography laboratory at a tertiary care academic pediatric hospital.
Of the 54 patients included in the analysis, 21 had ocular juvenile MG; 18 (86%) were initially treated with acetylcholinesterase inhibitors. Thirty-three patients had generalized juvenile MG, and all were initially treated with acetylcholinesterase inhibitors. Treatment response outcomes of objective physical examination findings and patient-reported change in symptoms and function correlated well with each another. Response rates to PLEX and IVIG were high.
Among 27 patients with generalized juvenile MG treated with PLEX, IVIG, or both, all 7 patients treated with PLEX alone responded, as did 5 of 10 patients receiving IVIG alone and 9 of 10 patients treated with both. Response rates were significantly higher (P = .04) with PLEX than with IVIG, and there were significant differences at follow-up in both objective and subjective improvements in children who received PLEX vs IVIG vs combined treatments.
The sample of children with ocular juvenile MG was too small for detailed statistical comparisons.
The youngest child who began PLEX by peripheral venous access was 9 years old, whereas the youngest child treated with IVIG was 9 months old. Eleven of 17 children who underwent thymectomy had significant postoperative improvement.
Viewpoint
A limitation of this study is its retrospective design, creating the possibility of selection bias. Nonetheless, the study supports the use of PLEX and/or IVIG as reasonable therapeutic options for juvenile MG, because both are associated with high response rates as maintenance therapies. However, the response rate appears to be more consistent with PLEX than with IVIG.
Cost is a drawback of these treatments. PLEX is more expensive than corticosteroid therapy, and IVIG is even more costly, but corticosteroids pose significant risks for harmful long-term adverse effects that are particularly troubling in young patients.
Abstract