The Safety Profile of Infliximab in Patients with Crohn's Disease: The Mayo Clinic Experience in 500 Patients

Background & Aims: The aim of this study was to evaluate the short- and long-term safety of infliximab in patients with Crohn's disease in clinical practice. Methods: The medical records of 500 consecutive patients treated with infliximab at the Mayo Clinic were reviewed and abstracted for demographic features and adverse events. The likelihood of a causal relationship to infliximab for each adverse event was determined by calculating an intrinsic likelihood (imputability) score. Results: The 500 patients received a median of 3 infusions and had a median follow-up of 17 months. Forty-three patients (8.6%) experienced a serious adverse event, of which 30 (6%) were related to infliximab. Acute infusion reactions occurred in 19 of 500 patients (3.8%). Serum sickness-like disease occurred in 19 of 500 patients and was attributed to infliximab in 14 (2.8%). Three patients developed drug-induced lupus. One patient developed a new demyelination disorder. Forty-eight patients had an infectious event, of which 41 (8.2%) were attributed to infliximab. Twenty patients had a serious infection: 2 had fatal sepsis, 8 had pneumonia (of which 2 cases were fatal), 6 had viral infections, 2 had abdominal abscesses requiring surgery, one had arm cellulitis, and one had histoplasmosis. Nine patients had a malignant disorder, 3 of which were possibly related to infliximab. A total of 10 deaths were observed. For 5 of these patients (1%), the events leading to death were possibly related to infliximab. Conclusions: Short- and long-term infliximab therapy is generally well tolerated. However, clinicians must be vigilant for the occurrence of infrequent but serious events, including serum sickness-like reaction, opportunistic infection and sepsis, and autoimmune disorders.