Myasthenia gravis

The need for universally accepted classifications, grading systems, and methods of analysis for patients undergoing therapy for MG is widely recognized and is particularly needed for therapeutic research trials. The Medical Scientific Advisory Board (MSAB) of the Myasthenia Gravis Foundation of America (MGFA) formed a Task Force in May 1997 to address these issues. Initially, the Task Force planned to develop classifications and outcome measures pertaining only to standardizing thymectomy trials. However, it quickly became apparent that their efforts should apply to all therapeutic trials for MG, and thus the scope of the mission was expanded.

During the development of these recommendations, the Task Force faced numerous dilemmas for which no universally satisfactory solution was available. Dilemmas were defined as “situations that require one to choose between two equally balanced alternatives or predicaments that seemingly defy satisfactory solutions.” The Task Force members agreed at the outset, however, that their primary goal was to develop a uniform set of classifications to be used in the comparative analysis of the various therapeutic interventions for MG. With this as the primary goal, a consensus was gradually developed. In developing a consensus, at least two meetings were held each year during a 3-year period. Between meetings there was exchange of all proposals by electronic and surface mail, consultation with national and international experts in the field, critical analysis of all proposals, and many revisions. All conflicts (both minor and major) were resolved by vote. Virtually all issues were eventually approved unanimously; a few received a plurality of six.

This report presents the work of the Task Force and proposes classification systems and definitions of response to therapy designed to achieve more uniformity in recording and reporting clinical trials and outcomes research. Although designed primarily for research purposes, we think physicians may find some of …