Safety and efficacy of immunoadsorption versus plasma exchange in steroid-refractory relapse of multiple sclerosis and clinically isolated syndrome: A randomised, parallel-group, controlled trial.

Background: Plasma exchange (PE) constitutes the standard therapy for steroid-refractory relapse in multiple sclerosis and clinically isolated syndrome. Immunoadsorption (IA) is an alternative method of apheresis which selectively removes immunoglobulines (Ig) while preserving other plasma proteins. Although IA is regarded as a well-tolerated, low-risk procedure, high-level evidence for its efficacy is lacking. Therefore, we sought to investigate whether IA is superior to PE in patients with acute relapse of multiple sclerosis or clinically isolated syndrome who had insufficiently responded to high-dose intravenous methylprednisolone (MP).

Methods: Patients with acute relapse of multiple sclerosis or clinically isolated syndrome and without complete clinical remission of symptoms after at least one cycle of high-dose intravenous MP therapy were enrolled to our randomised, controlled, parallel-group, monocentric trial. Eligible patients were aged at least 12 years and had no clinical or laboratory signs of systemic infection. Eligible patients were randomly assigned (1:1) to receive either IA or PE. Patients in both groups received 5 treatments on 5 consecutive days. In the IA group, the 2.0-fold individual total plasma volume was processed on day 1, and the 2.5-fold on days 2-5. In the PE group, 2 liters of plasma (corresponding to the 0.69 ± 0.12-fold individual total plasma volume) were removed each day and substituted by 5% human albumin solution. Patients were followed up directly after last apheresis as well as 2 and 4 weeks after last treatment. The primary endpoint was change of the Multiple Sclerosis Functional Composite (MSFC) after 4 weeks compared to baseline. Analyses of primary outcome and safety measures were done in all patients who received at least one treatment (intention-to-treat-population). The trial is registered with ClinicalTrials.gov, number NCT02671682.

Findings: Between January 21, 2016, and October 26, 2018, 63 patients were screened for eligibility, and 61 patients were randomly assigned to receive IA ( = 31) or PE ( = 30). All randomised patients were included in the intention-to-treat-analysis. For the primary outcome, the median improvement of MSFC after 4 weeks compared to baseline was 0.385 (IQR 0.200-0.675;  < 0.001) in the IA group and 0.265 (IQR 0.100-0.408;  < 0.001) in the PE group. Improvement in the IA group was significantly larger ( = 0.034) compared to PE. Response rates after 4 weeks were 86.7% in the IA group and 76.7% in the PE group. One deep venous thrombosis occurred in each group.

Interpretation: Both IA and PE were safe in patients with steroid-refractory relapse and resulted in significant improvements of the primary outcome MSFC after 4 weeks compared to baseline. IA patients showed significantly larger improvements of MSFC compared to PE patients after 4 weeks. The results indicate a potential superiority of IA compared to PE in treatment of steroid-refractory relapse in multiple sclerosis and clinically isolated syndrome, which has to be confirmed by future studies.

Funding: Fresenius Medical Care Deutschland GmbH, Bad Homburg, Germany.