Treatment of inflammatory bowel disease from now to the millennium

Inflammatory Bowel Disease: Updates on Molecular Targets for Biologics

Therapy for inflammatory bowel disease (IBD) has changed, with several new agents being evaluated. The era of anti-tumor necrosis factor (anti-TNF) antibody therapy saw remarkable progress in IBD therapy. Some patients, however, do not respond to anti-TNF treatment, or their response decreases over time. This phenomenon highlights the need to identify new molecular targets for therapy in IBD. The targets of new therapeutic molecules in IBD must aim to restore immune dysregulation by the inhibition of proinflammatory cytokines (TNF-α, interleukin [IL]-6, IL-13, IL-17, IL-18, and IL-21) and augmentation of the effect of anti-inflammatory cytokines (IL-10, IL-11, and transforming growth factor β) and to pursue new anti-inflammatory targets, such as regulatory T-cell therapy, Smad7 antisense, Janus-activated kinase inhibition, Toll-like receptor stimulation, leukocyte adhesion, and blockade of T-cell homing via integrins and mucosal addressin cellular adhesion molecule-1. In addition, potential molecular targets could restore mucosal barrier function and stimulate mucosal healing. Despite these potential targets, the value and clinical significance of most new molecules remain unclear, and clinical efficacy and safety must be better defined before their implementation in clinical practice. This article aims to review the promising and emerging molecular targets that could be clinically meaningful for novel therapeutic approaches.

Randomized, controlled trial of recombinant human interleukin-11 in patients with active Crohn's disease

BACKGROUND

Interleukin-11 is a mesenchymally derived cytokine with pleiotropic activities. A pilot study suggested therapeutic benefit of recombinant human interleukin-11 (rhIL-11) in patients with Crohn's disease.

AIM

To determine the safety and preliminary estimate of efficacy of rhIL-11 in treating active Crohn's disease.

METHODS

Patients with mild to moderately active Crohn's disease, defined as a Crohn's disease activity index (CDAI) > or = 220 and < or = 450, were enrolled in a multicentre trial. Stable doses of 5-aminosalicylates, antibiotics, 6-mercaptopurine or azathioprine were permitted with appropriate wash-in periods. Oral, intravenous or rectally administered corticosteroids were not allowed. Patients were randomized to 6 weeks of subcutaneous injection with rhIL-11 15 microg/kg or placebo weekly, or rhIL-11 7.5 microg/kg or placebo twice weekly. The primary end-point was per cent change in CDAI at week 6; the major secondary end-point was the proportion of patients in remission, defined as a 100 point decrease in CDAI and absolute CDAI < or = 150.

RESULTS

Baseline characteristics were similar among the 148 evaluated patients (49 placebo, 49 rhIL-11 15 microg/kg once weekly, 50 rhIL-11 7.5 microg/kg twice weekly). Treatment was well-tolerated, with mild injection site reactions occurring more frequently among patients treated with rhIL-11. Headache, oedema, and increased platelet count occurred significantly more often in the rhIL-11 7.5 microg/kg twice weekly group, but not the 15 microg/kg once weekly group. There was a trend toward decreased mean per cent change in CDAI in the rhIL-11 15 micro/kg once weekly group vs. placebo (-31.5% vs. -18.5%, 95% confidence interval for the difference -27.9-1.6%). A significantly greater proportion of patients receiving rhIL-11 15 microg/kg once weekly achieved remission compared to placebo (36.7% vs. 16.3%, 95% confidence interval for the difference 3.4-37.4%; 16.4% for rhIL-11 7.5 microg/kg, N.S.).

CONCLUSIONS

Weekly subcutaneous injection with rhIL-11 15 microg/kg is safe and effective in inducing remission in a subset of patients with active Crohn's disease.

Inflammatory bowel disease management. Some thoughts on future drug developments

This article is intended to stimulate thought and focus on those areas where we feel advances in drug therapy for inflammatory bowel disease may occur. It is not an extensive review of current practice, although this is considered where it is thought to be pertinent to future developments. There are several excellent reviews of current practice which we do not attempt to repeat, nor do we give a comprehensive set of references, but cite well referenced reviews where necessary. New therapeutic developments should ideally stem from an understanding of the cause of pathogenesis of a condition; alternatively, established therapies may be modified or used as a basis for progress. Since the causes of both ulcerative colitis and Crohn's disease remain unknown, most forward thinking on drug development must come from current practice, but remain open to novel approaches. Our thoughts on possible future treatments for inflammatory bowel disease are somewhat selective, and because of their speculative nature are unlikely to coincide with those of others-only the future will reveal genuine advances as they become incorporated into established practice.