A randomized and controlled study comparing immunoadsorption and plasma exchange in myasthenic crisis

Myasthenic crisis is the most serious life-threatening event in Myasthenia gravis patients, affecting up to 27% within the first two years after onset of disease. Extracorporeal removal of circulating autoantibodies against the nicotinic acetylcholine receptor (AChRAb) by methods of therapeutic apheresis, e.g. plasma exchange (PE) and immunoadsorption (IA) had been demonstrated as effective treatment especially in acute situations of myasthenic crisis. However, controlled data comparing clinical safety and efficacy of both methods in a clinical study were not available. Here the results of a prospective randomized controlled clinical trial are presented, investigating 19 patients with myasthenic crisis, who were randomized to receive either PE (n = 10) or IA (n = 9) in addition to combined drug treatment. Patients received 3 to 5 (mean 3.5 for PE, and 3.4 for IA) treatments over a period of 7 days with a predefined treatment volume of 1.5 l plasma (i.e., 20-25 ml/kg plasma representing 0.5-0.6 patients' plasma volumes). Clinical courses were monitored using disease specific clinical scores. After initiation of IA or PE the mean value of Myasthenia scores decreased equally until Day 14 of the post-treatment phase. Patients from both treatment groups improved to a stable clinical status of Oosterhuis Classes 1 and 2. Substantial reduction of AChRAb was documented after each session of PE or IA. In the treatment period 16 adverse effects (seven serious adverse events, SAE) in the PE and 10 (1 SAE) in the IA group were observed. In conclusion, IA proved to be equally effective compared with PE treatment in patients with myasthenic crisis. Three to five treatment sessions using low plasma volume dosage of 20-25 ml/kg were adequate to improve clinically relevant symptoms significantly in most patients.