A Case of Evanʼs Syndrome Triggered by Vedolizumab

Abstract

Clinical trials have shown Vedolizumab to be a safe and highly effective therapy in treating inflammatory bowel disease. Its unique gut-specific mechanism of action has made it an attractive agent in recent years. However, Vedolizumab's side effect profile and long-term effects are not yet fully understood. We report a patient with ulcerative colitis (UC) presenting with epistaxis found to have a Vedolizumab-induced severe immune-mediated thrombocytopenia and hemolytic anemia, otherwise known as Evan's syndrome. Our patient is a 26 year-old man with a history of ulcerative pancolitis who presented with epistaxis and hematuria one week after his first Vedolizumab infusion. In terms of his UC history, he had been diagnosed with UC one year prior through colonoscopy and was initially managed with Mesalamine and Adalimumab with persistent symptoms of bloody diarrhea and abdominal pain. He was then switched to Vedolizumab and within five days, began experiencing severe epistaxis and scant hematuria. Physical exam was notable only for mild left lower quadrant tenderness. He was found to have a severe thrombocytopenia with a nadir of 7 K/μL. He had findings consistent with a hemolytic anemia with an indirect bilirubinemia, elevated LDH, and decreased haptoglobin. Direct Coomb's testing was positive and he was diagnosed with Evan's syndrome. He was treated with corticosteroids, intravenous immunoglobulin, and Rituximab. Both his UC symptoms and blood counts improved on treatment. He was eventually discharged on a Prednisone taper. All of his blood counts returned to normal four weeks after discharge. Evan's syndrome is a rare autoimmune disorder characterized by a Coomb's positive autoimmune hemolytic anemia and thrombocytopenia. It has been associated with several disorders and medications. However, to our knowledge, this is the first documented case of Vedolizumab-induced Evan's syndrome. This case highlights the potential for a paradoxical immunogenicity associated with the drug. Although there is excellent safety data on Vedolizumab, clinicians should be aware of this potentially rare but serious side effect. Rapid recognition and treatment of this uncommon disorder is essential. Ongoing post-market drug safety monitoring may help to fully understand all of the potential long and short term side effects of Vedolizumab.2099 Figure 1 No Caption available.