Safety of Infliximab in Patients Suffering from Inflammatory Bowel Disease

Accessible online at: www.karger.com/dig Tumor necrosis factor-· (TNF-·) is a central cytokine in the inflammatory process associated with Crohn’s disease (CD). Infliximab, a chimeric IgG1 antibody directed against soluble and membrane-bound TNF-·, has shown efficacy both in luminal and fistulizing CD. It was approved in October 1998 by the US Food and Drug Administration for the treatment of moderate to severe CD refractory to conventional therapies. It can be used both to induce [1, 2] and to maintain remission [3, 4]. Among the adverse events associated with infliximab therapy in CD patients, infections have been reported already in the original study by Targan et al. [1]. In the pivotal ACCENT I maintenance trial [3], serious infections occurred in 4% of patients. In addition, malignant disorders were reported in 1% of the patients. Infusion reactions led to discontinuation of infliximab in 12 out of 573 patients. One patient was judged to have developed a lupus-like syndrome. In a report published in this issue of the journal, Seiderer et al. [5] review the safety of infliximab in 100 consecutive patients (92 CD, 7 ulcerative colitis and 1 indeterminate colitis). Adverse events were observed in 10 patients (2 with an acute infusion reaction, 1 with a serum sickness-like reaction, 4 with a bacterial or viral infection, 1 with pancytopenia and 2 with surgical complications). The authors concluded that infliximab appears to be a relatively safe therapeutic option for patients with severe inflammatory bowel disease. When a larger population of patients was studied, serious adverse events, including deaths, have been observed. The Mayo Clinic reviewed their experience in 500 patients treated with infliximab [6]. These patients received a median of three infusions and had a median follow-up of 17 months. Serious adverse events were observed in 8.6%, of which 6% were related to infliximab. Acute infusion reactions occurred in 3.8%. Serum sickness-like disease was observed in 19 patients and was attributed to infliximab in 14 (2.8%). Three patients developed druginduced lupus. Twenty patients had a serious infection and a total of 10 deaths were observed, of which 5 were possibly related to infliximab. Recently, preliminary data from the TREAT registry have been presented concerning the safety of infliximab in 5,807 patients (2,850 having received infliximab and 2,957 not) [7]. This study is possibly more representative of the real safety of infliximab, since only 20% of the patients were treated in academic centers. On the other hand, since reporting was on a voluntary basis, the study could be susceptible to substantial bias. In total, 11,504 infusions were analyzed with a mean follow-up of 0.9 year. Adverse reactions and serious adverse reactions occurred in 5.4 and 0.16%, respectively. A 10-fold increase in mortality was observed in patients receiving infliximab and concomitantly treated with steroids (OR 5.8). Serious infections were associated with female sex and current use of steroids or narcotic analgesics. No dif-