Bilateral Sequential Brachial Plexus Neuritis Following Immune Checkpoint Inhibitor Combination Treatment (P13-8.003)

Abstract

<h3>Objective:</h3> To report a rare, debilitating neurotoxicity to combination immunotherapy. <h3>Background:</h3> Neurologic immune related adverse events associated with ICI are rare; rapid diagnosis and treatment can limit morbidity. Combined ICI treatment is associated with more severe and rapid neurotoxicity. Only 4 BPN cases have been reported. Three were unilateral, predominantly involving the lower trunk (C8-T1) and highly steroid responsive. One affected the anterior interosseous and lateral antebrachial cutaneous nerves. <h3>Design/Methods:</h3> A 76-year-old woman with lung adenocarcinoma received 3 doses of Nivolumab and one dose of Ipilimumab. She developed numbness and pain, followed by worsening bilateral asymmetric arm weakness 3 weeks after receiving her last Nivolumab dose. Her weakness was diffuse, worse on the right, associated with loss of reflexes. It started on the right arm and involved left arm a week after. <h3>Results:</h3> EMG confirmed bilateral brachial plexopathy, predominantly affecting roots derived from C6–C7 on right and C5–C6 on left. CSF showed WBC 7, elevated protein 58 g/dL, no malignant cells, normal IgG index and infectious studies. MRI cervical spine and brachial plexus were unremarkable. She received IV methylprednisolone 1 mg/kg for 5 days, IV immunoglobulin total of 2 grams/kg with rapid improvement in her strength and pain. <h3>Conclusions:</h3> This may be the first report of bilateral sequential BPN with predominantly upper-mid trunk involvement after dual treatment with Nivolumab and Ipilimumab. Rapid workup, exclusion of confounding factors, and treatment with steroids and immunomodulating agents can lead to significant recovery of function from a debilitating process. <b>Disclosure:</b> Dr. Ozel has nothing to disclose. Dr. Chen has nothing to disclose. Dr. Woodman has nothing to disclose.