Case Review of Alternative Treatment in Patient With Immunotherapy Induced Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP)

Objective To emphasize recognition of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) due to Immune checkpoint inhibitor (ICI) therapy Atezolizumab and efficacy of steroids in treatment. Background Atezolizumab is an anti-programmed death-ligand 1 (PD-L1) immune-modulating drug that induces tumor-specific cytotoxic T-cell immunity against the PD-L1 overexpression of many aggressive lung cancers. IVIG was initially thought to have the same benefit in immunotherapy mediated CIDP however recent cases suggest better benefit with plasmapheresis and steroids. Design/Methods We report a case of CIDP in a 61-year-old female with high grade neuroendocrine carcinoma of the lung with extensive metastasis. After confirmation of diagnosis, patient began treatment with whole brain radiation therapy and 6 cycles of carboplatin/etoposide followed by atezolizumab maintenance every 21 days for 38 months. Initial treatment reaction included self-resolving loss of balance. Last dose of atezolizumab was given 9 days prior to brain biopsy of left frontal mass. Following biopsy, symptoms of generalized weakness and bilateral lower extremity weakness presented. When symptoms progressed, patient was admitted to hospital, 2-3 weeks after last dose of atezolizumab. Results The patient responded to treatment with steroids and cessation of atezolizumab, carboplatin, and etoposide. She recovered to her neurological baseline after a course of IV dexamethasone. Conclusions Among ICI therapy, atezolizumab has been less frequently reported with neurologic adverse events than other medications of its class. Increased recognition of the association between ICI and CIDP may improve early detection and improve potentially fatal outcomes. This case and an assessment of the literature indicate ICI induced CIDP may not respond to IVIG and plasmapheresis treatment with consistency. Although IVIG and plasmapheresis maintained efficiency in some reports, adverse outcomes of IVIG treatment may indicate alternative first-line treatment. This case reports successful recovery with the sole use of immunosuppressive therapy which should be considered to optimize future outcomes of ICI associated CIDP.