SHM Converge Scientific Abstract ePoster Gallery-Plasma Exchange for Immune Checkpoint Inhibitor Induced Acute Demyelinating Polyneuropathy

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This report describes a rare neurological immune-related adverse event from the immune checkpoint inhibitor atezolizumab: acute inflammatory demyelinating polyneuropathy (AIDP), also known as Guillain-Barré syndrome. The patient was a 69-year-old man with urothelial carcinoma who developed progressive bilateral leg weakness after starting atezolizumab. After three doses, his symptoms worsened to the point that he could no longer walk.<br /><br />Diagnostic testing, including nerve conduction studies, supported AIDP. He was initially treated with high-dose IV methylprednisolone followed by intravenous immunoglobulin (IVIG), which led to temporary improvement and restored his ability to walk. However, three weeks later, he deteriorated again, becoming unable to ambulate and needing help with toileting. Examination showed absent lower-extremity reflexes and impaired proprioception in his hands. Cerebrospinal fluid showed albuminocytological dissociation, and antiganglioside antibodies were negative. A repeat IVIG course did not improve his condition.<br /><br />Because of persistent weakness, he underwent five cycles of plasmapheresis (plasma exchange, PLEX). After PLEX, his strength improved substantially, reflexes returned, hand proprioception recovered, and follow-up MRI showed resolution of cervical nerve root enhancement. He was eventually able to walk with a cane.<br /><br />The authors conclude that this is the first reported case of atezolizumab-induced AIDP that was refractory to IVIG but responded to plasma exchange. They suggest PLEX can be an effective rescue treatment in such cases, though the optimal timing for initiating PLEX in immune checkpoint inhibitor-related AIDP remains uncertain and needs further study.

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Neha Verma

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Author List Edwin Peguero, Neha Verma, Sepideh Mokhtari, Yolanda Pina

Category Clinical Vignettes

Concept Immune Checkpoint Inhibitor

Concept Atezolizumab

Concept Acute inflammatory demyelinating polyradiculoneuropathy

Concept Immune Checkpoint Inhibitor Toxicity

Concept Guillain-Barré Syndrome

Distinguished Non-Finalist

Presenter Organization Moffitt Cancer Center

Presenting Author Neha Verma

Track Adult

Keywords

atezolizumab

acute inflammatory demyelinating polyneuropathy

Guillain-Barré syndrome

immune checkpoint inhibitor

urothelial carcinoma

bilateral leg weakness

intravenous immunoglobulin

plasmapheresis

plasma exchange

neurological adverse event

Immune Checkpoint Inhibitor

Atezolizumab

Acute inflammatory demyelinating polyradiculoneuropathy

Immune Checkpoint Inhibitor Toxicity

Guillain-Barré Syndrome