The incidence and management of infusion reactions to infliximab: a large center experience

Newer therapies for inflammatory bowel disease

Recent controlled and uncontrolled trial data in inflammatory bowel disease have suggested several new avenues of possible therapies and refined our understanding of the uses and selectiveness of anti-tumor necrosis factor (TNF)-based therapies. Infliximab remains the only proven effective anti-TNF therapy, whereas others have proven ineffective (etanercept, CDP-571) or of limited utility (thalidomide, CDP-870). A Crohn's disease Clinical trial Evaluating infliximab in a New long-term Treatment regimen (ACCENT I) and ACCENT II trials supported the strategy of using 5 to 10 mg/kg of infliximab on an every 8-week basis for maintenance of remission, although in clinical practice many physicians take variable approaches to maintenance of remission dosing schedules. On the other hand, no controlled trial data to date have supported the use of infliximab in ulcerative colitis. Therapies utilizing novel mechanistic approaches, such as hematopoietic growth factors, mitogen-activated protein (MAP)-kinase inhibition, and peroxisome proliferator activated receptor gamma ligand receptor binding have shown promise in small uncontrolled trials and await confirmation of their utility in randomized, placebo-controlled trials. Newer biologic (natalizumab) or cytokine-based therapies (monoclonal antibody to interleukin-6) have shown preliminary evidence of efficacy in controlled trials, but neither have yet been approved by the US Food and Drug Administration and, therefore, have not been commercialized. However, tacrolimus, a potent calcineurin inhibitor and inhibitor of interleukin-2 expression, has shown efficacy in Crohn's disease, albeit at the cost of substantial potential toxicity.

Safety overview of new disease-modifying antirheumatic drugs

Beginning in 1998, a surge of new agents has expanded treatment options for rheumatoid arthritis (RA) patients. Although the disease modifying potential of these agents is encouraging, their use must be weighed against an evolving array of new safety concerns. Because of the popularity of these agents with patients and rheumatologists alike, clinicians must be prepared to discuss the potential risks associated with novel disease-modifying antirheumatic drugs and biologic therapies as they begin to appear with greater frequency in practice. This article discusses the safety issues arising from clinical trial and postmarketing experience with several new and commonly used agents, with specific emphasis on adalimumab, etanercept, infliximab, anakinra, and leflunomide.

Key role of mast cells and their major secretory products in inflammatory bowel disease

Historically, mast cells were known as a key cell type involved in type I hypersensitivity. Until last two decades, this cell type was recognized to be widely involved in a number of non-allergic diseases including inflammatory bowel disease (IBD). Markedly increased numbers of mast cells were observed in the mucosa of the ileum and colon of patients with IBD, which was accompanied by great changes of the content in mast cells such as dramatically increased expression of TNF-α, IL-16 and substance P. The evidence of mast cell degranulation was found in the wall of intestine from patients with IBD with immunohistochemistry technique. The highly elevated histamine and tryptase levels were detected in mucosa of patients with IBD, strongly suggesting that mast cell degranulation is involved in the pathogenesis of IBD. However, little is known of the actions of histamine, tryptase, chymase and carboxypeptidase in IBD. Over the last decade, heparin has been used to treat IBD in clinical practice. The low molecular weight heparin (LMWH) was effective as adjuvant therapy, and the patients showed good clinical and laboratory response with no serious adverse effects. The roles of PGD2, LTC4, PAF and mast cell cytokines in IBD were also discussed. Recently, a series of experiments with dispersed colon mast cells suggested there should be at least two pathways in man for mast cells to amplify their own activation-degranulation signals in an autocrine or paracrine manner. The hypothesis is that mast cell secretogogues induce mast cell degranulation, release histamine, then stimulate the adjacent mast cells or positively feedback to further stimulate its host mast cells through H₁ receptor. Whereas released tryptase acts similarly to histamine, but activates mast cells through its receptor PAR-2. The connections between current anti-IBD therapies or potential therapies for IBD with mast cells were discussed, implicating further that mast cell is a key cell type that is involved in the pathogenesis of IBD. In conclusion, while pathogenesis of IBD remains unclear, the key role of mast cells in this group of diseases demonstrated in the current review implicates strongly that IBD is a mast cell associated disease. Therefore, close attentions should be paid to the role of mast cells in IBD.

Optimizing anti-tumor necrosis factor strategies in inflammatory bowel disease

The introduction of infliximab, a mouse/human chimeric monoclonal antibody to tumor necrosis factor (TNF), is an important advance in the treatment of Crohn's disease. Infliximab is effective for induction and maintenance of remission in patients with inflammatory luminal and fistulizing disease. The development of human antichimeric antibodies (HACAs) has led to infusion reactions and loss of efficacy in patients treated with infliximab. Strategies to reduce the frequency of HACA formation include induction of immunologic tolerance with a three-dose regimen at 0, 2, and 6 weeks followed by systematic maintenance dosing every 8 weeks; concomitant immunosuppressive therapy with azathioprine, 6-mercaptopurine, or methotrexate; and premedication with intravenous corticosteroids. Humanized or fully human anti-TNF biotechnologic agents, including CDP571, CDP870, etanercept, adalimumab, and onercept, are theoretically less immunogenic than the chimeric antibody infliximab. Etanercept is not effective for Crohn's disease. CDP571 is not effective in unselected patients with active Crohn's disease, but it may be effective in patients with elevated C-reactive protein. The efficacy of CDP870, adalimumab, and onercept is under investigation. The different mechanisms of action of these anti-TNF agents may account for their variable efficacy. Their benefits, however, must be considered in the context of their risks, including infusion reaction; delayed hypersensitivity-like reaction; new onset of autoimmunity, with rare cases of drug-induced lupus and new-onset demyelination; and the potential for rare but serious infections.