Rates of Postoperative Recurrence of Crohn's Disease and Effects of Immunosuppressive and Biologic Therapies.

BACKGROUND & AIMS: The Rutgeerts' scoring system is used to evaluate patients with Crohn's disease (CD) following ileocolic resection, based on endoscopic findings at the anastomosis and in the neoterminal ileum. We investigated rates of clinical and surgical recurrence of CD after surgery and effect of therapy modification based on post-operative endoscopic findings. METHODS: We collected data from 365 adults with CD (20% with Rutgeerts' score i0, 10% with score i1, 49% with score i2, 12% with score i3, 9% with score i4) who underwent ileocolonoscopy within 12 months of ileocolic resection with anastomosis from 2000 through 2013 at 2 centers in Belgium and France. Patients were followed for 3 y or more after the ileocolonoscopy. Clinical post-operative recurrence (POR) was defined as occurrence of CD symptoms along with biologic, radiologic, and/or endoscopic features of disease activity; modified surgical POR was defined as either an endoscopic or surgical intervention. RESULTS: After a median follow-up time of 88 months, 48% of patients had clinical POR and 26% had modified surgical POR. Rates of survival without clinical POR or a modified surgical POR were lower in patients with Rutgeerts' scores of i2, i3, or i4 compared to patients with scores of i0 or i1 (P < .001 and P = .02). New immunosuppressant or biological therapy was initiated following endoscopy in 129/254 patients (51%) with Rutgeerts' score of i2, i3, or i4 vs 7/111 patients (6%) with scores of i0 or i1 (odds ratio for new therapy, 14.9; 95% CI, 7.1-36.8; P < .001). A modest decrease in risk of clinical POR was observed for patients with Rutgeerts scores of i3 or i4 after initiation of immunosuppressive or biological therapy based on endoscopic findings (Breslow P = .03), but this was not observed for patients with scores of i2 (Breslow P = .46). CONCLUSIONS: Use of immunosuppressants and tumor necrosis factor antagonists to treat patients with an asymptomatic endoscopic post-operative recurrence of CD did not reduce long-term risk of clinical recurrence in patients with Rutgeerts' scores of i2, but it had a small effect in patients with scores of i3 or i4.

Optimizing biologic therapies for inflammatory bowel disease (ulcerative colitis and Crohn's disease).

The introduction of biologic agents and particularly of anti-tumor necrosis factor antibodies dramatically changed the therapeutic algorithm in patients with inflammatory bowel diseases. Although the efficacy of these agents has been demonstrated clearly, optimal treatment strategies are debated. Recent trials advocate the introduction of biologic agents at an early stage to prevent debilitating complications. However, significant adverse events have led to careful selection of patients who will benefit most from long-term treatment with biologic agents. Once on biologic therapy, scheduled maintenance therapy is recommended to minimize the risk of loss of response. Nevertheless, treatment adaptation is frequently necessary in patients who lose response. Interventions encompass strategies to increase drug exposure by increasing the dose or decreasing the dosing interval, or by changing to another biologic agent. Finally, it remains unclear if and when a biologic agent can be stopped in patients with long-standing remission.

Biological therapies for inflammatory bowel diseases.

Crohn's disease and ulcerative colitis are chronic disabling inflammatory bowel diseases (IBDs). Although the causes of IBD are unknown, defects in innate and adaptive immune pathways have been identified and biological therapies that target key molecules have been designed. Infliximab, a chimeric immunoglobulin (Ig)G1 monoclonal antibody to tumor necrosis factor, dramatically improved treatment of patients with Crohn's disease and ulcerative colitis. Infliximab has achieved treatment goals such as mucosal healing and decreasing the need for hospitalizations and surgeries. Although several anti-tumor necrosis factor therapies have been developed, there is a great need for drugs that target other pathways. Natalizumab, an antibody against the integrin alpha4 subunit, blocks leukocyte adhesion and has reached the clinic in the United States but has not been approved in the European Union; other anti-adhesion molecules currently are under development. Additional approaches under clinical development include therapeutics that target cytokines, such as interleukin-12/23, as well as those that block T-cell signaling. The use of recombinant human proteins, including immunoregulatory cytokines and growth factors, has not been successful so far. The efficacy of each therapy must be shown in carefully designed clinical programs. Biological therapies carry a definite safety risk, so their place in treatment algorithms must be defined carefully.

Dose-response effect of arabinoxylooligosaccharides on gastrointestinal motility and on colonic bacterial metabolism in healthy volunteers.

OBJECTIVE: Arabinoxylooligosaccharides (AXOS) are non-digestible in the upper gastrointestinal tract and have been shown to exert prebiotic effects in animals. The aim of this study was to characterize the influence of AXOS with an average degree of polymerization of 15 and an average degree of arabinose substitution of 0.26 (AXOS-15-0.26) on gastrointestinal motility and colonic bacterial metabolism in healthy human volunteers. METHODS: Twelve healthy volunteers received five test meals, containing different amounts of AXOS-15-0.26, with one week intervals between each test meal. Breath tests were used to measure gastric emptying rate, oro-cecal transit time (OCTT) and hydrogen excretion. Colonic bacterial metabolism was estimated using the biomarkers lactose-[(15)N, (15)N']-ureide ((15)N-LU) and p-cresol. RESULTS: Gastric emptying and OCTT were not influenced by addition of varying amounts of AXOS-15-0.26. Administration of 2.2g or 4.9 g AXOS-15-0.26 significantly decreased the urinary (15)N-excretion (respectively p = 0.008 and p = 0.035) as compared to the baseline, whereas fecal (15)N-excretion was significantly increased (respectively p = 0.034 and p = 0.019). This shift from urinary to fecal (15)N-excretion suggests a higher uptake or incorporation by bacteria due to the stimulation of colonic bacterial growth and/or metabolic activity. Furthermore, a significant increase in hydrogen excretion after administration of 2.2g (p = 0.002) and 4.9 g (p = 0.004) AXOS-15-0.26 was observed. No influence on urinary p-cresol excretion was observed. CONCLUSION: These findings suggest that a minimal dose of 2.2g AXOS-15-0.26 favorably modulates the colonic bacterial metabolism in healthy humans. However, long term studies are required to confirm a possible prebiotic effect.

Omega-3 free fatty acids for the maintenance of remission in Crohn disease: the EPIC Randomized Controlled Trials.

CONTEXT: Maintenance therapy for Crohn disease features the use of immunosuppressive drugs, which are associated with an increased risk of infection. Identification of safe and effective maintenance strategies is a priority. OBJECTIVE: To determine whether the oral administration of omega-3 free fatty acids is more effective than placebo for prevention of relapse of Crohn disease. DESIGN, SETTING, AND PATIENTS: Two randomized, double-blind, placebo-controlled studies (Epanova Program in Crohn's Study 1 [EPIC-1] and EPIC-2) conducted between January 2003 and February 2007 at 98 centers in Canada, Europe, Israel, and the United States. Data from 363 and 375 patients with quiescent Crohn disease were evaluated in EPIC-1 and EPIC-2, respectively. INTERVENTIONS: Patients with a Crohn's Disease Activity Index (CDAI) score of less than 150 were randomly assigned to receive either 4 g/d of omega-3 free fatty acids or placebo for up to 58 weeks. No other treatments for Crohn disease were permitted. MAIN OUTCOME MEASURE: Clinical relapse, as defined by a CDAI score of 150 points or greater and an increase of more than 70 points from the baseline value, or initiation of treatment for active Crohn disease. RESULTS: For EPIC-1, 188 patients were assigned to receive omega-3 free fatty acids and 186 patients to receive placebo. Corresponding numbers for EPIC-2 were 189 and 190 patients, respectively. The rate of relapse at 1 year in EPIC-1 was 31.6% in patients who received omega-3 free fatty acids and 35.7% in those who received placebo (hazard ratio, 0.82; 95% confidence interval, 0.51-1.19; P = .30). Corresponding values for EPIC-2 were 47.8% and 48.8% (hazard ratio, 0.90; 95% confidence interval, 0.67-1.21; P = .48). Serious adverse events were uncommon and mostly related to Crohn disease. CONCLUSION: In these trials, treatment with omega-3 free fatty acids was not effective for the prevention of relapse in Crohn disease. TRIAL REGISTRATION: clinicaltrials.gov Identifiers: EPIC-1: NCT00613197, EPIC-2: NCT00074542.

The influence of inulin on the absorption of nitrogen and the production of metabolites of protein fermentation in the colon.

In the present study, the production and fate of bacterial metabolites in the colon were investigated in a direct way using two substrates labelled with stable isotopes: lactose [(15)N,(15)N]ureide as a source of labelled ammonia and egg proteins intrinsically labelled with [(2)H4]tyrosine as a precursor of [(2)H4]p-cresol. Both ammonia and phenolic compounds are believed to be carcinogenic. Stimulation of carbohydrate fermentation in order to prevent accumulation of these toxic metabolites was induced by inclusion of inulin in a test meal or by addition of inulin to the daily diet, allowing us to distinguish between changes induced by the actual presence of a fermentable carbohydrate and effects caused by a long-term dietary intervention. When a single dose of inulin was administered together with the labelled substrates, a significant increase in faecal (15)N excretion, accompanied by a proportional decrease in urinary (15)N excretion was observed, probably reflecting an enhanced uptake of ammonia for bacterial biosynthesis, since an increased concentration of labelled N in bacterial pellets was found. A statistically significant reduction of urinary [(2)H4]p-cresol excretion was also noted. Upon supplementation of inulin to the daily diet during 4 weeks, however, only a tendency towards decreased urinary excretion of both labelled and unlabelled p-cresol was noted. Further studies are warranted to confirm these results in a larger cohort.

Focus on mechanisms of inflammation in inflammatory bowel disease sites of inhibition: current and future therapies.

Anti-TNF antibodies were the first biologic agents registered to treat patients who have CD and, more recently, patients who have UC. The sequence of events underlying the inflammatory reaction in IBD is extremely complex, however, and involves both the innate and antigen-driven adaptive immune system. Novel therapies are directed at several key players of this cascade. Blockade of T-cell proliferation and activation and inhibition of T-cell cytokines has been most extensively targeted by clinical trials in humans. Inhibition of adhesion molecules and the use of selected growth factors seem to have therapeutic potential. Restoration of regulatory T-cell and dendritic-cell function is still waiting to be explored in clinical trials. Although an increasing number of biologic therapies for IBD are being developed, the discovery of the full spectrum of treatment modalities is only beginning. Often, however, the clinical efficacy of biologic agents is investigated, and for some molecules is established, before mechanisms of action are specifically explored. Eight years after the Food and Drug Administration approved infliximab for the treatment of luminal CD, it is not known how this anti-TNF antibody actually dampens inflammation in IBD. The advent of newer anti-TNF agents is only postponing the answer.

Safety issues with biological therapies for inflammatory bowel disease.

PURPOSE OF REVIEW: The purpose of this review is to summarize recent evidence describing specific complications associated with the use of biological therapy derived from controlled trials and from post-marketing surveillance. RECENT FINDINGS: Biological therapies, particularly anti-tumour necrosis factor antibodies, are increasingly used in patients with Crohn's disease and ulcerative colitis. Some adverse events, such as serious infections, are a consequence of the immunomodulatory effect of biological agents, while other complications, such as the induction of autoimmune phenomena, neurotoxicity and the development of an immune response to engineered proteins, are class or molecule-specific. Although the immunopathogenesis of these side effects is often a matter of debate, they have been observed not only in inflammatory bowel disease, but also in other immune disorders such as rheumatoid arthritis and psoriasis. SUMMARY: The benefits of biological agents clearly outweigh the risks. Nevertheless, they are associated with specific toxicity, and this requires the attention of the clinician.

Emerging biological treatments in inflammatory bowel diseases.

Although the advent of infliximab has changed the treatment paradigm and goals in inflammatory bowel disease, it does not provide a cure for it and recent evidence has demonstrated that the immunogenicity of this chimeric anti-tumor necrosis factor antibody is associated with secondary loss of response and intolerance. In ulcerative colitis the efficacy of infliximab was demonstrated in two large clinical trials, but long-term maintenance efficacy data are lacking. Novel biological agents have entered clinical development and pioneering trials have been reported in the last 2 years. For Crohn's disease the fully human IgG1 anti-tumor necrosis factor monoclonal adalimumab, and the humanized anti-alpha4-integrin IgG4 antibody, natalizumab have yielded the most promising results in controlled trials, but also agents inhibiting the crucial interleukin-12/interferon-gamma feedback loop suggest therapeutic potential. For severe ulcerative colitis infliximab has been shown to be an effective rescue treatment and the anti-T-cell CD3 antibody has shown promising open-label results. Crucial in the development of novel biological agents, however, is the benefit:risk ratio. As illustrated by unexpected but devastating brain infections with anti-adhesion molecules, clinicians should be aware that the powerful immunomodulatory capacity of biologicals necessitates a rigorous safety follow-up.

An historical overview of the treatment of Crohn's disease: why do we need biological therapies?

Crohn's disease is a disabling inflammatory bowel disease that may involve any part of the gastrointestinal tract. The disease decreases quality of life and leads to complications including stenoses, abscesses, and fistulae necessitating repeated surgeries and bowel resections. Until the late 1990s, standard therapies included mainly glucocorticosteroids, 5-aminosalicylic acid (5-ASA), antibiotics, and to a lesser extent, immunosuppression with azathioprine (AZA)/6-mercaptopurine (6-MP) or methotrexate. These therapies, especially glucocorticosteroids, mainly controlled symptoms without modifying the long-term disease course. Glucocorticosteroids also do not induce sustained mucosal healing. The lack of healing capacity mirrors the absent long-term efficacy of these drugs. Moreover, long-term use of glucocorticosteroids is associated with serious and sometimes irreversible side effects. AZA/6-MP are effective disease-modifying therapies that have been used in patients who are refractory to or relapse after steroids. Unfortunately, these agents have yet to have an established optimal benefit due to variations in genetically determined metabolism. With the advent of biologicals, new treatment aims have been advanced, including induction of remission with bowel healing both short term and long term, as well as reduction in the rate of complications, surgeries, and mortality.

Medical therapy for Crohn's disease strictures.

Intestinal fibrostenosis is a frequent and debilitating complication of Crohn's disease (CD), not only resulting in small bowel obstruction, but eventually in repeated bowel resection and short bowel syndrome. Over one third of patients with CD have a clear stenosing disease phenotype, often in the absence of luminal inflammatory symptoms. Intestinal fibrosis is a consequence of chronic transmural inflammation in CD. As in other organs and tissues, phenotypic transformation and activation of resident mesenchymal cells, such as fibroblasts and smooth muscle cells, underlie fibrogenesis in the gut. The molecular mechanisms and growth factors involved in this process have not been identified. However, it is clear that inflammatory mediators may have effects on mesenchymal cells in the submucosa and the muscle layers that are profoundly different from their action on leukocytes or epithelial cells. Transforming growth factor-beta (TGF-beta), for instance, has profound anti-inflammatory activity in the mucosa and probably serves to keep physiologic inflammation at bay, but at the same time it appears to be driving the process of fibrosis in the deeper layers of the gut. Tumor necrosis factor, on the other hand, has antifibrotic bioactivity and pharmacologic inhibition of this cytokine carries a theoretical risk of enhanced stricture formation. Endoscopic management of intestinal strictures with balloon dilation is an accepted strategy to prevent or postpone repeated surgery, but careful patient selection is of paramount importance to ensure favorable long-term outcomes. Specific medical therapy aimed at preventing or reversing intestinal fibrosis is not yet available, but candidate molecules are emerging from research in the liver and in other organs.

Anti-tumor necrosis factor treatment restores the gut barrier in Crohn's disease.

OBJECTIVES: A primary defect of the tight junctions and, hence, increased intestinal epithelial permeability has been proposed as a basic pathogenic event in Crohn's disease. Challenge of the mucosal immune system by the commensal gut flora would then result in chronic inflammation. Alternatively, increased permeability could be the result of inflammation. Our aim was to study intestinal permeability in refractory Crohn's disease before and after treatment with monoclonal chimeric antibodies directed against tumor necrosis factor (TNF) to investigate whether the abnormal permeability persists after control of inflammation. METHODS: Twenty-three patients with active Crohn's disease were evaluated before and 4 wk after a single infusion of 5 mg/kg infliximab. Intestinal permeability was studied by measurement of urinary excretion of 51Cr-EDTA after oral intake. RESULTS: The increased permeation of 51Cr-EDTA through the small intestine (1.63% interquartile range [IQR] 1.06-2.07) and the overall permeation (3.27% IQR 2.40-4.38) before therapy decreased significantly after infliximab infusion to values (1.04% IQR 0.74-1.54 and 2.42% IQR 2.03-2.80, respectively) in the range of those found in normal volunteers (1.12% IQR 0.85-1.58 and 2.28% IQR 1.88-2.86, respectively). CONCLUSION: Inhibiting the proinflammatory cytokine tumor necrosis factor dramatically reduces gut inflammation and largely restores the gut barrier in Crohn's disease. Our data confirm the central role of TNF in gut barrier modulation in inflammatory conditions in vivo.