Electrophysiological predictors of response to subcutaneous immunoglobulin therapy in chronic inflammatory demyelinating polyneuropathy.

Objective: To assess axonal function prior to subcutaneous immunoglobulin (SCIG) therapy or placebo in relation to relapse in chronic inflammatory demyelinating polyneuropathy (CIDP) to determine whether axonal damage can predict therapy response.
Methods: Relapse rates in patients from the Polyneuropathy and Treatment with Hizentra (PATH) study, where patients were treated with placebo or SCIG (IgPro20), were analyzed by baseline (post-intravenous immunoglobulin stabilization) axonal damage (≤1 mV peroneal compound muscle action potential) status.
Results: In patients with non-axonal damage, relapses were significantly higher with placebo (73.0%) than IgPro20 (0.2 g/kg: 39.1%, 0.4 g/kg: 19.2%). In patients with axonal damage, IgPro20 had no effect on relapse (placebo: 25.0%, IgPro20: 0.2 g/kg: 30.0%, 0.4 g/kg: 19.4%). Patients with axonal damage relapsed significantly less on placebo versus non-axonal damage, but they also demonstrated higher baseline disability.
Conclusion: Axonal damage may correspond to relapse upon treatment withdrawal; patients with axonal damage relapse less, possibly reflecting poor response to immunoglobulin therapy, while non-axonal damage patients may experience more relapse, perhaps indicating better treatment response.
Significance: In CIDP patients with axonal loss, immunoglobulin therapy may not be as effective. Assessing axonal damage could help guide therapy, with immunoglobulins ideally used before substantial axonal damage arises.
Competing Interests: Declaration of Competing Interest MA has no conflicts to declare. VB is a consultant to CSL Behring, Grifols, Union Chimique Belge, Takeda, Alnylam, Alexion, ArgenX, Roche and Novo-Nordisk. She serves on international scientific advisory boards for the Myasthenia Gravis Foundation of America and Guillain-Barré Syndrome/Chronic Inflammatory Demyelinating Polyneuropathy (CIDP/GBS) Foundation International, and has received research support from CSL Behring, Grifols, Union Chimique Belge, and ArgenX. H-PH received fees for consulting or serving on steering committees or advisory boards from Baxter, Bayer Healthcare, Biogen, CSL Behring, Geneuro, Kedrion, Laboratoire francais du Fractionnement et des Biotechnologies, MedImmune, Merck, Novartis, Octapharma, Receptos Celgene, Roche, and Teva, with approval by the Rector of Heinrich-Heine-University Düsseldorf. J-PL is a CSL Behring employee and biostatistician for this study. OM is an employee of CSL Behring. BLD was a CSL Behring employee during this study. All authors participated in the development and approval of this manuscript.
(Copyright © 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)