Eculizumab as a Disease-Modifying Therapy in Chronic Inflammatory Demyelinating Polyneuropathy (CIDP): A Case Report

Background and aims: Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare immune-mediated disorder; about 20%-30% of patients do not adequately respond to first-line treatments (immunoglobulins, therapeutic plasmapheresis, and corticosteroids) posing diagnostic and therapeutic challenges. Case report: We report the case of a 58-year-old man diagnosed with CIDP. During follow-up, he progressively became refractory to all first-line treatments. Therefore, 20 months after the diagnosis, an add-on therapy with Rituximab was tried. Despite previous works supporting the use of Rituximab in refractory CIDP, in our case, the patient experienced relapses and progressive increases in disability. After the exclusion of potential CIDP mimics and considering the histological findings that showed complement activation, we opted for an innovative therapeutic approach with Eculizumab that granted a significant clinical and neurophysiological benefit that persists after 7 months of follow-up. Interpretation: CIDP pathogenesis is characterized by a complex interplay of different immunopathological mechanisms, and the complement system may play a major role. The present case supports the role of complement-dependent toxicity in CIDP and suggests that complement-targeted therapies may represent a well-tolerated and effective alternative for CIDP treatment.