Detect it so you can treat it: A case series and proposed checklist to detect neurotoxicity in checkpoint therapy

BACKGROUND: Checkpoint inhibitors show impressive and durable responses in various cancer types and provide new avenues for cancer immunotherapy. However, these drugs have a variety of adverse events. Common autoimmune-related adverse effects include fatigue, hepatitis, skin rash, endocrine deficiencies, and colitis. Neurotoxicity has been reported, but its incidence and course remain unclear. METHODS: To illustrate the broad spectrum of neurotoxicity, we exemplarily report the neurological adverse events of five patients with melanoma and one patient with differentiated thyroid cancer who received checkpoint inhibitors at Essen University Hospital (Essen, Germany). RESULTS: After treatment with ipilimumab, nivolumab or pembrolizumab, neurotoxic effects included hypophysitis-associated neck pain and headache, Guillain-Barré syndrome, transverse myelitis, acute brachial plexus neuritis, and ocular myasthenia gravis. CONCLUSIONS: Checkpoint inhibitor therapy remains a success story; however, neurological immune-related adverse events may cause severe life-threatening conditions. We propose a guide for the early detection of neurological adverse events during routine clinical treatment to prevent more severe courses of checkpoint inhibitor-induced neurotoxicity.