Acute Inflammatory Demyelinating Polyneuroradiculopathy with Ipilimumab in Metastatic Melanoma: A Case Report and Review of Literature

Ipilimumab (Bristol-Myers Squibb Co., New York, NY) is a novel anticancer medication used for the treatment of metastatic melanoma. The exact mechanism of its action remains unclear; however, data from previous clinical trials postulates the immunomodulatory activity of ipilimumab to enhance therapeutic effectiveness. Ipilimumab was approved by the Food and Drug Administration (FDA) in March 2011 for use in stage III and IV of unresectable metastatic melanoma. We report a single case of acute inflammatory demyelinating polyneuroradiculopthy (AIDP) in the patient treated with ipilimumab for recurrent metastatic melanoma. The patient presented with multiple falls that started after the third infusion of ipilimumab. Other symptoms were hoarseness of voice, motor deficits in his right arms, and tingling in both hands. The deficits progressed into near complete loss of movement and sensation in all four extremities over the course of two weeks. However, his bladder and bowel functions were intact. There was no history of fever, recent travel, exposure to sick contacts, insect bites, or gastrointestinal symptoms. Along with strong immune-mediated pharmacological response towards cancer cells, ipilimumab also induces immune-related adverse events (irAEs) within normal tissues by the mechanism of molecular mimicry.