Randomised controlled trial of azathioprine and 5-aminosalicylic acid for treatment of steroid dependent ulcerative colitis

Thiopurine hepatotoxicity in inflammatory bowel disease: the role for adding allopurinol

BACKGROUND

Immunomodulator therapy with the thiopurine analogues azathioprine or 6-mercaptopurine is commonly prescribed for the treatment of inflammatory bowel disease (IBD). Drug adverse effects and the lack of efficacy, however, commonly require withdrawal of therapy. Allopurinol, a xanthine oxidase inhibitor, was recently evaluated in its role in modifying thiopurine metabolism and improving drug efficacy in IBD.

OBJECTIVE

This article reviews the role and safety of allopurinol co-therapy in the setting of thiopurine hepatotoxicity and/or non-responsiveness in IBD.

METHODS

Published articles on thiopurines in the treatment of IBD were examined.

CONCLUSION

The addition of low dose allopurinol to dose-reduced thiopurine analogue seems safe but careful monitoring for adverse effects and profiling of thiopurine metabolites is essential. There is evidence of improved immunomodulator efficacy and reduced hepatotoxicity clinically but further confirmatory studies are required before more definitive treatment recommendations can be given.

Are we giving azathioprine too late? The case for early immunomodulation in inflammatory bowel disease

Inflammatory bowel disease (IBD) includes two entities, Crohn’s disease and ulcerative colitis. Both are chronic conditions with frequent complications and surgical procedures and a great impact on patient’s quality of life. The thiopurine antimetabolites azathioprine and 6-mercaptopurine are widely used in IBD patients. Current indications include maintenance therapy, steroid-dependant disease, fistula closure, prevention of infliximab immunogenicity and prevention of Crohn’s disease recurrence. Surprisingly, the wide use of immunosuppressants in the last decades has not decreased the need of surgery, probably because these treatments are introduced at too late stages in disease course. An earlier use of immunossupressants is now advocated by some authors. The rational includes: (1) failure to modify IBD natural history of present therapeutic approach, (2) demonstration that azathioprine can induce mucosal healing, a relevant prognostic factor for Crohn’s disease and ulcerative colitis, and (3) demonstration that early immunossupression has a very positive impact on pediatric, recently diagnosed Crohn’s disease patients. We are now awaiting the results of new studies, to clarify the contribution of azathioprine, as compared to infliximab (SONIC Study), and to demonstrate the usefulness of azathioprine in recently diagnosed adult Crohn’s disease patients (AZTEC study).

Are we giving azathioprine too much time?

Azathioprine is currently the key drug in the maintenance treatment of inflammatory bowel diseases. However, there are still some practical issues to be resolved: one is how long we must maintain the drug. Given that inflammatory bowel diseases are to date chronic, non-curable conditions, treatment should be indefinite and only the loss of efficacy or the appearance of serious side effects may cause withdrawal. As regards to efficacy and their maintenance over time, evidence supports the continuous usefulness of the drug in the long term: in fact its withdrawal very substantially increases the risk of relapse. About side effects, azathioprine is a relatively well tolerated drug and even indefinite use seems safe. The main theoretical risks of prolonged use would be the myelotoxicity, hepatotoxicity, and the development of cancer. In fact, serious bone marrow suppression or serious liver damage are uncommon, and can be minimized with proper use of the drug. Recent metanalysis suggests that the risk of lymphoma is real, but the individual risk is rather low, and decision analysis suggests a favorable benefit/risk ratio in the long term. Therefore, in patients with inflammatory bowel diseases in whom azathioprine is effective and well tolerated, the drug should not be stopped. This recommendation concerns the use of azathioprine as a single maintenance drug, and is not necessarily applicable to patients receiving concomitant biological therapy.

Review article: treatment algorithms to maximize remission and minimize corticosteroid dependence in patients with inflammatory bowel disease

BACKGROUND

Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory diseases of the intestine, which frequently require surgery for complications or failure of medical therapy.

AIM

To seek evidence and provide direction for clinicians on optimal strategies to enable steroid free remission in inflammatory bowel disease.

METHODS

Scientific literature was reviewed using MEDLINIE with a specific focus on medical therapies for inducing and maintaining remission of CD and UC. The results were discussed at a roundtable meeting to reach a consensus on key issues.

RESULTS

Several therapies have demonstrated efficacy for the treatment of active, moderate-to-severe CD and UC. These include agents, which induce remission [corticosteroids, infliximab and adalimumab (CD only)] or maintain remission and spare corticosteroids [azathioprine, mercaptopurine, methotrexate (CD only), infliximab and adalimumab (CD only)]. Wide variability exists in the use of these agents.

CONCLUSION

Treatment strategy algorithms are developed for use of these therapies that maximize remission and minimize corticosteroid dependence in patients with moderate-to-severe CD and UC.

Predictive factors associated with immunosuppressive agent use in ulcerative colitis: a case-control study

BACKGROUND

Some patients with ulcerative colitis (UC) require immunosuppressants as maintenance therapy.

AIM

To assess epidemiological, clinical and disease factors at diagnosis that predict immunosuppressant use in UC.

METHODS

All UC patients diagnosed between 1992 and 2005 and currently managed in the inflammatory bowel disease (IBD) clinic were included. Forty-three patients who currently or previously received azathioprine (AZA) or mercaptopurine (MP) for UC were compared with 130 controls. Charts were reviewed and logistic regression analyses were applied to identify factors associated with AZA or MP use.

RESULTS

In univariate model, seven factors at diagnosis correlated with AZA use: male gender [odds ratio (OR) 2.2]; left-sided or extensive colitis or pancolitis (OR 8.7-14.1); systemic steroid use within the first 6 months of diagnosis (OR 5.1); more than 10 bowel movements daily (OR 6.4); persistent or mostly blood in stool (OR 2.8); endoscopic proven moderate to severe disease (OR 7.2-12.0) and requirement of hospitalization (OR 2.7) on diagnosis. In multivariate model, the first three factors were shown to be statistically significant.

CONCLUSION

Male gender, initial presentation with severe and extensive disease clinically and endoscopically, requirement of hospitalization on diagnosis or systemic steroids within 6 months of diagnosis are predictive factors for immunosuppressant use in UC.

Comparative effectiveness of azathioprine in Crohn's disease and ulcerative colitis: prospective, long-term, follow-up study of 394 patients

BACKGROUND

The long-term efficiacy for thiopurinic drugs in Crohn's disease (CD), and particularly in ulcerative colitis (UC), has been insufficiently studied.

AIM

To evaluate prospectively and compare the long-term effectiveness of azathioprine (AZA) in CD and UC.

METHODS

Three hundred and ninety-four AZA treated patients were included consecutively included. Truelove-modified index and CDAI were used to assess effectiveness. Hospitalizations and surgical procedures were recorded.

RESULTS

Two hundred and thirty-eight patients with CD and 156 with UC received AZA for a median of 38 months.

EFFECTIVENESS

Partial response/remission was achieved in 34%/49% of CD patients and in 47%/42% of UC (nonstatistically significant differences). STEROID TREATMENT: Prior to AZA, 49% of CD patients were receiving steroids, whereas only 8% needed steroids after therapy (P < 0.001). Corresponding figures in UC patients were 39% vs. 9% (P < 0.001). HOSPITALIZATIONS: Prior to AZA, the rate of hospitalizations in CD was 0.190 per-patient-year, while after treatment, it decreased to 0.099 (P < 0.001). Corresponding hospitalization rates in UC were 0.108 vs. 0.038 (P < 0.001).

SURGERY

The rate of surgery in CD prior/after AZA was 0.038/0.011 per-patient-year (P < 0.001). The number of surgical interventions in UC prior/after AZA treatment was 26/0 (the rate per-patient-year was 0.018/0) (P < 0.001).

CONCLUSIONS

Our results confirm the effectiveness of AZA in inflammatory bowel disease, not only in the short term but also in the long term, resulting in a steroid sparing effect and in both a reduction in the number of hospitalizations and surgical procedures. AZA is similarly effective for both CD and UC patients.

Exposing the weaknesses: a systematic review of azathioprine efficacy in ulcerative colitis

BACKGROUND

Published trials evaluating the efficacy of 6-thioguanine anti-metabolites in the treatment of ulcerative colitis (UC) have yielded conflicting results. We performed a systematic review and meta-analysis to evaluate the clinical efficacy of 6-thioguanine anti-metabolites for the maintenance of clinical remission after standard induction with corticosteroids.

METHODS

A comprehensive search of online databases was conducted. Only randomized controlled trials with 6-thioguanine antimetabolites within a minimum duration of follow-up of 6 months were selected.

RESULTS

Five trials were included in the meta-analysis. The pooled relative risk estimate for "success of treatment" with azathioprine (AZA) compared to 5-aminosalicylic acid or placebo was 1.42 [95% confidence interval (CI): 0.93-2.17, p = 0.109]; when only trials of a higher quality were used, a pooled relative risk estimate of 2.05 (95% CI: 1.30-3.23, p = 0.002) was obtained.

CONCLUSIONS

Pooled results demonstrated a modest efficacy of AZA for the treatment of ulcerative colitis. However, the use of AZA for the management of UC is not based on high-quality evidence.

Thiopurine methyltransferase activity combined with 6-thioguanine metabolite levels predicts clinical response to thiopurines in patients with inflammatory bowel disease

BACKGROUND/AIMS

6-Mercaptopurine and its prodrug azathioprine are effective for the treatment of inflammatory bowel disease. Thiopurine methyltransferase is important for the metabolism of thiopurines. However, there is controversy as to the clinical utility of measuring thiopurine methyltransferase enzyme activity and 6-thioguanine nucleotide levels. Our aim was to determine if thiopurine methyltransferase enzyme activity and 6-thioguanine nucleotide level monitoring would predict response to therapy with thiopurines in patients with inflammatory bowel disease.

METHODS

Baseline thiopurine methyltransferase enzyme activity prior to initiation of therapy with either 6-mercaptopurine or azathioprine was determined in 39 patients with inflammatory bowel disease. The association between clinical response and thiopurine methyltransferase activity and 6-thioguanine nucleotide levels singly or in combination were analysed.

RESULTS

Seventeen of 39 patients (44%) responded to 6-mercaptopurine or azathioprine therapy. Thiopurine methyltransferase enzyme activity below the mean of 30.5 U was significantly associated with clinical response. The thiopurine methyltransferase low phenotype was associated with response in 65% vs. 29% in individuals with thiopurine methyltransferase enzyme activity above 30.5 U (p = 0.05). There was no correlation between thiopurine methyltransferase activity and 6-thioguanine nucleotide levels. The maximal 6-thioguanine nucleotide levels did not predict clinical response. When combining thiopurine methyltransferase enzyme activity and 6-thioguanine nucleotide levels, the combination of thiopurine methyltransferase low/6-thioguanine nucleotide high was associated with response in 7/7 (100%) vs. only 2/8 (25%) with the combination of thiopurine methyltransferase high/6-thioguanine nucleotide low (p=0.01).

CONCLUSIONS

Thiopurine methyltransferase activity inversely correlated with clinical response to thiopurine treatment in inflammatory bowel disease. Thiopurine methyltransferase enzyme activity below 30.5 U combined with a post-treatment 6-thioguanine nucleotide level > 230 pmol/8 x 10(8) erythrocytes was the best predictor of response.

Therapeutic options in acute severe ulcerative colitis

Ulcerative colitis is a relapsing-remitting inflammatory disease affecting the colon and is associated with considerable morbidity. In acute severe attacks, there continues to be an associated mortality rate of 1-2%, even in specialist units. During an acute severe exacerbation, approximately two-thirds of patients will respond to intravenous corticosteroid therapy, the accepted first-line therapy in such cases. For steroid-refractory patients, options are limited to surgery (colectomy) or second-line agents, such as ciclosporin or infliximab, used in an attempt to salvage the colon. Considerable debate exists over the optimal management of such patients. During the last decade, an increased understanding of the pathogenesis of inflammatory bowel disease has led to the rapid development of other biological agents, such as basiliximab and visilizumab. Novel methods, such as leucopheresis, have been studied and other established immunomodulatory agents, such as tacrolimus, have also been suggested. The purpose of this review is to highlight some of the areas of recent development in the treatment of acute severe ulcerative colitis and review important safety data, with a particular emphasis on biological agents.

Unfractionated or low-molecular weight heparin for induction of remission in ulcerative colitis

BACKGROUND

There are a limited number of treatment options for patients with ulcerative colitis (UC). An increased risk of thrombosis in UC coupled with an observation that UC patients being treated with anticoagulant therapy for thrombotic events had an improvement in their bowel symptoms led to trials examining the use of unfractionated heparin (UFH) and low molecular weight heparins (LMWH) in patients with active UC.

OBJECTIVES

To review randomized trials examining the efficacy of unfractionated heparin (UFH) or low molecular weight heparins (LMWH) for remission induction in patients with ulcerative colitis.

SEARCH STRATEGY

The MEDLINE (PUBMED), and EMBASE databases, The Cochrane Central Register of Controlled Trials, the Cochrane IBD/FBD group specialized trials register, review papers on ulcerative colitis, and references from identified papers were searched in an effort to identify all randomized trials studying UFH or LMWH use in patients with ulcerative colitis. Abstracts from major gastroenterological meetings were searched to identify research published in abstract form only.

SELECTION CRITERIA

Each author independently reviewed potentially relevant trials to determine their eligibility for inclusion based on the criteria identified above. The Jadad scale was used to assess study quality. Studies published in abstract form only were included if the authors could be contacted for further information.

DATA COLLECTION AND ANALYSIS

A data extraction form was developed and used to extract data from included studies. At least 2 authors independently extracted data. Any disagreements were resolved by consensus. Data were analyzed using Review Manager (RevMan 4.2.9). Data were analyzed on an intention-to-treat basis, and treated dichotomously. In cross-over studies, only data from the first arm were included. The primary endpoint was induction of remission, as defined by the studies. Data were combined for analysis if they assessed the same treatments (UFH or LMWH versus placebo or other therapy). If a comparison was only assessed in a single trial, P-values were derived using the chi-square test. If the comparison was assessed in more than one trial, summary test statistics were derived using the Peto odds ratio and 95% confidence intervals (95% CI). The presence of heterogeneity among studies was assessed using the chi-square test (a P value of 0.10 was regarded as statistically significant). If statistically significant heterogeneity was identified the odds ratio and 95% CI were calculated using a random effects model.

MAIN RESULTS

There were 2 randomized, double-blind studies assessing LMWH versus placebo for the treatment of mild-moderate active UC. Various outcomes were assessed in the 2 studies. LMWH showed no benefit over placebo in any outcome, including clinical remission (OR 1.09; 95% CI 0.26 to 4.63; P = 0.91), clinical improvement (OR 0.73; 95% CI 0.32 to 1.66; P = 0.45 and OR 1.09; 95% CI 0.18 to 6.58; P = 0.92 in the two studies, respectively), endoscopic improvement (OR 1.35; 95% CI 0.29 to 6.18; P = 0.70), or histological improvement (OR 2.00; 95% CI 0.45 to 8.96; P = 0.37). LMWH was also not beneficial when added to standard therapy in a randomized open-label trial in which the outcome measures included clinical remission (OR 0.71; 95% CI 0.17 to 2.95; P = 0.64), clinical improvement (OR 2.00; 95% CI 0.31 to 12.75; P = 0.46), endoscopic remission (OR 0.71; 95% CI 0.17 to 2.95; P = 0.64), or endoscopic improvement (OR 1.40; 95% CI 0.34 to 5.79; P = 0.64). LMWH was well-tolerated and provided no significant benefit for quality of life. One study examining UFH versus corticosteroids in the treatment of severe UC demonstrated inferiority of UFH in clinical improvement as an outcome measure (OR 0.02; 95% CI 0 to 0.40; P = 0.01). Patients assigned to UFH did not improve clinically. More patients assigned to UFH had rectal hemorrhage as an adverse event.

AUTHORS' CONCLUSIONS

There is no evidence to support the use of UFH or LMWH for the treatment of active UC. No further trials examining these drugs for patients with UC are warranted, except perhaps a trial of UFH in patients with mild disease. Any benefit found would need to be weighed against a possible increased risk of rectal bleeding in patients with active UC.

Ulcerative proctitis: a review of pharmacotherapy and management

BACKGROUND

Ulcerative proctitis (UP) is a common presentation of ulcerative colitis (UC).

OBJECTIVE

To summarize available literature on up-to-date management and pharmacotherapy of UP patients.

METHODS

Extensive Medline/Embase literature search was performed to identify relevant articles.

RESULTS/CONCLUSION

Topical medication with rectally administered 5-aminosalicylic acid (5-ASA)/corticosteroid suppositories or enemas is effective treatment for most UP patients. Locally administered 5-ASA is more efficacious than oral compounds. The combination of topical 5-ASA and oral 5-ASA or topical steroids should be considered for escalation of treatment. Maintenance treatment is indicated in all UC cases. 5-ASA suppositories are suggested as first-line maintenance therapy if accepted by patients, although oral 5-ASA as maintenance therapy might prevent proximal extension of the disease. After re-assessment, chronically active patients refractory or intolerant to 5-ASAs and corticosteroids may require immunomodulators or biological therapy. Exceptional cases may require a proctocolectomy.

Quality of life of patients with ulcerative colitis: past, present, and future

Quality of life (QoL) is vitally important to patients with chronic illnesses such as ulcerative colitis (UC) and has been assessed in observational, cross-sectional, and cohort studies. However, relatively few clinical trials have evaluated the QoL of patients with UC. Recently, greater availability of the necessary tools has facilitated the undertaking of studies showing that QoL of patients with UC is reduced significantly compared with that of the general population. Studies using disease-specific instruments have identified disease severity as the strongest predictor of QoL, with other disease-related predictors including type of medical or surgical treatment and the efficacy, tolerability, and acceptability to patients of particular types of medical or surgical treatments. Other factors, such as comorbid medical or psychosocial problems and adherence to treatment, also affect QoL. Combined use of generic and disease-specific instruments in clinical trials can ensure that all clinically relevant unexpected events (generic instrument) and important improvement or deterioration (disease-specific instrument) are captured. For accurate outcomes assessment, the use of comprehensively validated instruments is critical. The need for the development and evaluation of new instruments will be determined by the mechanisms and targets of novel therapies. Ultimately, QoL assessment of effective therapies will play a strong role in pharmacoeconomic evaluations, providing health policy makers with the evidence to support the treatments that can most effectively normalize QoL through complete symptom resolution, minimal side effects, and convenient administration.

How are Azathioprine and 6-mercaptopurine dosed by gastroenterologists? Results of a survey of clinical practice

BACKGROUND

Azathioprine (AZA) and 6-mercaptopurine (6-MP) are accepted as effective therapy for Crohn's disease and ulcerative colitis. Although general guidelines have been suggested for weight-based dosing of thiopurines, no standard of care has been established. Clinical trials have demonstrated efficacy for weight-based dosing of AZA at 2.5 mg/kg/day and 6-MP at 1.5 mg/kg/day. Escalation of dosing is recommended within 2 weeks of initiating therapy. The aim was to determine the prescribing practices of community practice gastroenterologists with respect to 6-MP/AZA dosing.

METHODS

Questionnaires were distributed via a mail database or during gastroenterology society meetings to gastroenterologists in NY, NJ, and CT. Questionnaires ascertained starting doses of AZA/6-MP, use of thiopurine methyltransferase (TPMT) enzyme testing, and strategy for dose optimization.

RESULTS

A total of 145 questionnaires were collected. Twenty-four percent of gastroenterologists escalated the dose within 2 weeks after initiating therapy. The majority used weight-based dosing as their target of therapy. Thirty-five percent reported measuring TPMT levels and 46% used metabolite monitoring.

CONCLUSIONS

Most gastroenterologists take longer than recommended to raise the dose of AZA/6-MP. Although the majority of gastroenterologists reported maximal dosages based on weight, there may be a delay in achieving this goal. Optimizing dosing of AZA/6-MP may improve efficacy and reduce the need to use additional therapy.

Review article: evolving concepts in treatment and disease modification in ulcerative colitis

BACKGROUND

More than two-thirds of ulcerative colitis patients experience at least one relapse over a period of 10 years. Treatments that reduce the likelihood of relapses also reduce the risk of long-term complications.

AIM

To review three topics: the current standard of treatment for ulcerative colitis, evolving concepts in treatment, and disease modification as a treatment goal of the future.

RESULTS

Currently, 5-aminosalicylates are the standard treatment for the induction and maintenance of remission in mild-to-moderate ulcerative colitis patients. Evidence suggests that patients who take oral 5-aminosalicylates regularly are nearly six times more likely to experience regression in disease severity than those who do not. Additional treatment options such as corticosteroids, immunomodulators, biological therapies and ciclosporin are available for moderate-to-severe ulcerative colitis patients, or those who do not respond to 5-aminosalicylate. Surgery becomes pertinent for more than one-third of ulcerative colitis patients during the course of their disease. With the availability of a variety of therapies, advances in surgery and improved management strategies, a better understanding of patient treatment expectations can help improve the quality of care for ulcerative colitis patients.

CONCLUSIONS

Disease modification is increasingly becoming a treatment goal in the management of ulcerative colitis. However, long-term studies are needed to examine further the disease modifying role of 5-aminosalicylates.

Review and clinical perspectives for the use of infliximab in ulcerative colitis

Infliximab is a chimeric, monoclonal anti-tumour necrosis factor-alpha antibody. It has been previously demonstrated to be an effective treatment for patients with Crohn's disease who do not achieve the desired response with conventional treatments. Although the etiology of ulcerative colitis (UC) differs from that of Crohn's disease, randomized controlled trials have demonstrated that infliximab is also beneficial for the treatment of moderate to severe UC in patients who are either intolerant of or refractory to immunosuppressant agents or steroids, or those who are steroid-dependent. A review of the literature is followed by practical recommendations regarding infliximab that address the needs of clinicians and UC patients. Where there is a lack of evidence-based information, the expert panel provides its combined opinion derived from the members' clinical experiences.

Should azathioprine and 5-aminosalicylates be coprescribed in inflammatory bowel disease?: an audit of adverse events and outcome

BACKGROUND

An interaction between azathioprine and 5-aminosalicylates may exist, but the mechanism remains unclear.

OBJECTIVES

To investigate the occurrence of adverse events and efficacy of azathioprine with or without mesalazine.

METHOD

Retrospective study of 199 patients. In all, 95 patients received azathioprine alone (monotherapy); 104 received combination of 5-aminosalicylates and azathioprine (dual therapy). Data were recorded on adverse events, azathioprine dose and thiopurine methyl transferase (TPMT) level. In 85 of the patients, relapse rate was compared in the two groups.

RESULTS

Adverse events were more common in dual therapy group, 50/104, than in monotherapy group, 29/95; chi=6.4, P=0.05. Most patients had normal TPMT activity. No relationship between TPMT activity and adverse events was observed. A total of 105 patients took (>or=2 mg/kg) azathioprine; adverse events occurred in 26% compared with 54% taking less than 2 mg/kg (chi=15.8, P<0.0001). Discontinuation of azathioprine owing to adverse events was found to be higher in dual therapy group, 26/50, than in monotherapy group, 7/29 (chi=5.0, P<0.01). Relapse rate was higher in the dual therapy group (29/49) than with monotherapy (12/36) (chi=5.5, P<0.02).

CONCLUSION

Adverse events are more common in patients taking dual therapy than azathioprine monotherapy. Adverse events are unrelated to dose of azathioprine. Patients receiving dual therapy are more likely to relapse than patients receiving monotherapy.

Tolerability and safety of mercaptopurine in azathioprine-intolerant patients with inflammatory bowel disease

BACKGROUND

Azathioprine intolerance is a common clinical problem, requiring drug withdrawal in up to 30% of patients. The successful use of mercaptopurine is described, but data to support this strategy are needed.

AIMS

To assess the tolerability of mercaptopurine in inflammatory bowel disease patients previously intolerant of azathioprine, and identify predictive factors.

METHODS

Sixty-one azathioprine-intolerant patients (31 males, median age at diagnosis 32 years, 31 with Crohn's disease, 30 with ulcerative colitis) who had been treated with mercaptopurine were identified. Intolerances included nausea and vomiting, flu-like illness, neutropenia, hepatotoxicity and pancreatitis.

RESULTS

Mercaptopurine was tolerated by 59% (36 of 61) of azathioprine-intolerant patients (median dose 1.0 mg/kg), 61% (17 of 28) in patients with azathioprine-related nausea and vomiting, 61% (11 of 18) with flu-like illness, 33% (three of nine) with hepatotoxicity, 100% (one of one) with neutropenia, 100% (three of three) with rash and 0% (zero of one) with pancreatitis. Mercaptopurine intolerance was frequently for a different adverse event. Those intolerant of mercaptopurine were younger (28.4 years vs. 37.0 years; P = 0.014) and more frequently female (14/30 vs. 2/29, P = 0.027). Mercaptopurine tolerability was not affected by diagnosis, location, behaviour, surgery, smoking, family history or extra-intestinal manifestations.

CONCLUSION

Mercaptopurine may be tolerated in up to 60% of azathioprine-intolerant patients, and treatment should be considered, particularly if intolerance was due to nausea, vomiting, flu-like illness or rash.

Treatment of inflammatory bowel disease: a review of medical therapy

Crohn's disease (CD) and ulcerative colitis (UC) are chronic inflammatory diseases of the gastrointestinal tract. While a cure remains elusive, both can be treated with medications that induce and maintain remission. With the recent advent of therapies that inhibit tumor necrosis factor (TNF) alpha the overlap in medical therapies for UC and CD has become greater. Although 5-ASA agents have been a mainstay in the treatment of both CD and UC, the data for their efficacy in patients with CD, particularly as maintenance therapy, are equivocal. Antibiotics may have a limited role in the treatment of colonic CD. Steroids continue to be the first choice to treat active disease not responsive to other more conservative therapy; non-systemic steroids such as oral and rectal budesonide for ileal and right-sided CD and distal UC respectively are also effective in mild-moderate disease. 6-mercaptopurine (6-MP) and its prodrug azathioprine are steroid-sparing immunomodulators effective in the maintenance of remission of both CD and UC, while methotrexate may be used in both induction and maintenance of CD. Infliximab and adalimumab are anti-TNF agents approved in the US and Europe for the treatment of Crohn's disease, and infliximab is also approved for the treatment of UC.

Are we ready for top-down therapy for inflammatory bowel diseases: pro

Until the 1990s, inflammatory bowel diseases (IBD) were treated with conventional drugs, such as mesalazine, corticosteroids and thiopurines, which are effective in a proportion of IBD patients. Despite the introduction of immunosuppressive drugs, a significant number of IBD patients have a disabling disease course and, on average, a poor quality of life. The discovery of anti-TNF strategies and the development of biologics targeting several other pathways, important in the pathogenesis of ulcerative colitis and Crohn's disease, introduced a pivotal discussion. Central to this discussion is the question of whether these new therapies should be introduced early or late in the course of the disease. Important factors that are relevant for this discussion are quality of life, need for corticosteroids and surgery. This article aims to explore whether we are indeed ready for a top-down approach toward biologics.

Positioning biologic therapy for Crohn's disease and ulcerative colitis

Over the past decade, the introduction of biologic agents such as tumor necrosis factor-alpha and alpha4 integrin leukocyte adhesion molecule inhibitors has provided new and effective treatment options for patients with inflammatory bowel disease (IBD). Recent debates have centered on where biologics should be positioned within the current treatment strategy so as to maximize efficacy while balancing risk. This review highlights the current position biologics hold relative to conventional therapies within the current "step-up" treatment strategy. It also critically appraises emerging data, testing the hypothesis that positioning biologics early in the IBD treatment algorithm ("top-down" strategy) results in superior outcomes compared with the current step-up strategy, in which biologics are used only in patients failing conventional therapies or who are steroid dependent.

Methotrexate for induction of remission in ulcerative colitis

BACKGROUND

Ulcerative colitis is a chronic inflammatory bowel disease. Corticosteroids and 5-aminosalicylates are the most commonly used therapies. However, many patients require immunosuppressive therapy when their disease becomes steroid-refractory or dependent. Methotrexate is a medication that is effective for treating a variety of inflammatory diseases, including Crohn's disease. This review was performed to determine the effectiveness of methotrexate at inducing remission in patients with ulcerative colitis.

OBJECTIVES

To review randomized trials examining the efficacy of methotrexate for remission induction in patients with ulcerative colitis.

SEARCH STRATEGY

MEDLINE (PUBMED), EMBASE, The Cochrane Central Register of Controlled Trials, the Cochrane IBD/FBD group specialized trials register, review papers on ulcerative colitis, and references from identified papers were searched in an effort to identify all randomized trials studying methotrexate use in patients with ulcerative colitis. Abstracts from major gastroenterological meetings were searched to identify research published in abstract form only.

SELECTION CRITERIA

Randomized controlled trials comparing methotrexate with placebo or an active comparator in patients with active ulcerative colitis were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by each author, analyzed on an intention-to-treat basis, and treated dichotomously. Methotrexate was compared to placebo in one trial. The odds ratio and 95% confidence interval were calculated and P-values were derived using the chi-square test.

MAIN RESULTS

Only 1 trial fulfilled the inclusion criteria. This study randomized 30 patients to methotrexate 12.5 mg orally weekly and 37 patients to placebo for 9 months. During the study period, 14/30 patients (47%) assigned to methotrexate, and 18/37 patients (49%) assigned to placebo achieved remission and complete withdrawal from steroids (OR 0.92, 95% CI 0.35-2.42; P = 0.87). The mean time to remission was 4.1 months in the methotrexate group and 3.4 months in the placebo group.

AUTHORS' CONCLUSIONS

A single trial of methotrexate 12.5 mg orally weekly showed no benefit over placebo in remission induction in patients with active ulcerative colitis. There is no evidence on which to base recommendations for treating ulcerative colitis patients with methotrexate. However, the possibility of a type 2 error exists, and a higher dose of methotrexate may be effective. A new trial in which adequate numbers of patients are randomized to placebo or a higher dose of methotrexate should be considered.

The role of mesalamine in the treatment of ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory condition of unclear etiology affecting the large bowel, most commonly the rectum and extending proximally in a continuous fashion. The overall principle in the pathophysiolgy of ulcerative colitis is the dysregulation of the normal immune system against an antigenic trigger leading to a prolonged mucosal inflammatory response. The diagnosing of UC is made by combining the clinical picture, tissue biopsy with the endoscopic appearance of mucosal ulceration, friable, edematous, erythematous granular appearing mucus. The approach to therapy of UC has been dependent on severity of symptoms with frontline therapy being salicylate based sulfasalazine. Newer formulations of salicylates based drugs with fewer side-effects have been developed. These are free of the sulphur component and are composed of 5-ASA, without the sulfapyridine carrier molecule. Mesalamine is one of these 5-ASA based agents that are currently available and indicated for treatment of UC. In mild/moderate active disease mesalamine has response rates between 40%-70% and remission rates of 15%-20%. Considering that the efficacy of 5-ASA is dose dependent, 4.8 g/day and 2.4 g/day have been shown to be the optimal dosages for mild-moderate distal active disease and for maintenance therapy, respectively. Patients with moderately active ulcerative colitis treated with 4.8 g/d of mesalamine are significantly more likely to achieve overall improvement at week 6 compared to patients treated with 2.4 g/d. In the setting of left-sided distal colitis (proctitis), topical (rectal) formulations have been found to be superior to oral aminosalicylates at inducing remission. Mesalamine has been shown to be safe in short term use with a dose-response efficacy without dose-related toxicity.

Current and future therapies for inflammatory bowel disease

The introduction of biologic agents to the therapeutic arsenal has dramatically impacted the way we treat patients with inflammatory bowel disease, allowing clinicians to achieve lasting remission in patients who are unresponsive to conventional therapies. New research continues to expand our understanding of the inflammatory cascade of ulcerative colitis and Crohn's disease, revealing a host of potential therapeutic targets for intervention. As we look toward the future in this rapidly developing field, we must learn how best to incorporate these new agents into the treatment algorithm to enhance or replace conventional therapies.

Review article: the management of steroid dependency in ulcerative colitis

BACKGROUND

Approximately 20% of patients with ulcerative colitis have a chronic active disease often requiring several courses of systemic steroids in order to achieve remission, but followed by relapse of symptoms during steroid tapering or soon after their discontinuation. Although short term control of symptoms can be achieved with steroid treatment, this pattern of drug response, known as steroid-dependency, leads to important complications of the treatment, while a significant proportion of patients requires colectomy.

AIM

To review the studies currently available specifically evaluating the management of steroid-dependent ulcerative colitis.

RESULTS

The clinical and biological mechanisms of steroid-dependency are not well understood compared with those determining steroid-refractoriness. Very few evidence-based data are available concerning the management of patients with steroid-dependent ulcerative colitis. The therapeutic role of aminosalicylates, thiopurines, methotrexate, infliximab, leukocyte apheresis and other drugs in the treatment of steroid-dependent ulcerative colitis are evaluated.

CONCLUSIONS

Outcomes of studies in steroid-refractory patients may not be applicable to steroid-dependency. Trials are needed to define the correct approaches and new strategies to ameliorate the therapy of steroid-dependent ulcerative colitis.

[Medical therapy of inflammatory bowel diseases: ulcerative colitis]

There are fewer significant changes in the medical therapy of ulcerative colitis (UC) compared to Crohn's disease. The most important factors that determine therapy are disease extent and severity. 5-aminosalicylates (5-ASA) constitute the treatment of choice in mild-to-moderate UC. The efficacy of new compounds (e.g. mesalazine) is only mildly improved compared to sulphasalazine; however, their use has become more frequent due to a more favorable side effects profile. Topical medication is more effective in proctitis and distal colitis, and the combination of topical and orally-administered drugs is superior to oral therapy alone also in extensive disease. Thus, this latter regimen should be considered for cases where the escalation of treatment is required. Systemic steroids still represent the first line therapy in acute, severe UC, while in patients who do not respond to steroids, cyclosporine and infliximab should be considered as a second line therapy and as alternatives for colectomy. Maintenance treatment is indicated in all UC cases. 5-ASA compounds are suggested as first line maintenance therapy with the optimal dose still being under investigation. Topical compounds are effective also for maintenance in distal colitis or proctitis, if accepted by the patients. Immunosuppressives, especially azathioprine, should be considered in chronically active, steroid dependent or resistant patients. According to recent publications, azathioprine is almost equally effective in UC and CD. The question of chemoprevention is important during maintenance. There are increasing data supporting the notion that aminosalicylates may lower the risk for UC-associated colorectal cancer. The most important changes in the management of UC are the more frequent use of topical aminosalicylates and azathioprine, the availability of infliximab in severe UC, and increasing use of aminosalicylates for chemoprevention of colorectal carcinoma. Furthermore, adequate attention is needed to better organize the patient-doctor relationship and for greater adherence to medical therapy.

Severe pulmonary toxicity after azathioprine/6-mercaptopurine initiation for the treatment of inflammatory bowel disease

Azathioprine and 6-mercaptopurine (6-MP) are effective in inflammatory bowel disease (IBD). However, between 10% and 29% of patients treated with these drugs are forced to stop therapy due to side effects. Pulmonary toxicity due to azathioprine/6-MP has been reported infrequently. We describe 3 patients who developed severe, noninfectious pulmonary toxicity within 1 month after the initiation of azathioprine or 6-MP for the treatment of IBD colitis (2 Crohn's disease and 1 ulcerative colitis). All patients presented with dyspnea, cough, and fever after initiation of azathioprine/6-MP. Evaluation for infectious etiologies, including bronchoscopy (3/3 patients) and open-lung biopsy (2/3 patients) was negative. Histopathologic examination of the lung biopsies revealed bronchiolitis obliterans organizing pneumonia in one, and usual interstitial pneumonitis in another patient. Cessation of purine analog therapy resulted in clinical improvement in all 3 cases. Azathioprine/6-MP-related pulmonary toxicity is a rare but serious side effect, and it is important for clinicians to have a high index of suspicion for this adverse reaction which occurs within 1 month after initiation of treatment for IBD.

Omega 3 fatty acids (fish oil) for maintenance of remission in ulcerative colitis

BACKGROUND

Omega-3 fatty acids (n-3, fish oil) have been shown to have anti-inflammatory properties. Therefore, n-3 therapy may be beneficial in chronic inflammatory disorders such as ulcerative colitis.

OBJECTIVES

To systematically review the efficacy and safety of n-3 for maintaining remission in ulcerative colitis (UC).

SEARCH STRATEGY

The following databases were searched from their inception without language restriction: Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Healthstar, PubMed, and ACP journal club. Experts were contacted for unpublished data.

SELECTION CRITERIA

Randomized placebo-controlled trials (RCT) of fish oil for maintenance of remission in UC were included. Studies must have enrolled patients (of any age group) who were in remission at the time of recruitment, and were followed for at least six months. The intervention must have been fish oil given in pre-defined dosage. Co-interventions were allowed only if they were balanced between the study groups. The primary outcome was relapse rate and the secondary outcome was frequency of adverse events. Other outcomes to assess efficacy were change in disease activity scores and time to first relapse.

DATA COLLECTION AND ANALYSIS

Two independent investigators reviewed studies for eligibility, extracted the data and assessed study quality. Meta-analysis weighted by the Mantel-Haenszel method was performed using RevMan 4.2.8 software. Random or fixed effect models were used according to degree of heterogeneity and subgroup analyses were performed to explore heterogeneity. A sensitivity analysis was performed excluding a study of questionable quality .

MAIN RESULTS

The three studies that were included used different formulation and dosing of n-3 but none used enteric coated capsules. The pooled analysis showed a similar relapse rate in the n-3 treated patients and controls (RR 1.02; 95% CI 0.51 to 2.03; P = 0.96). Combining the studies resulted in virtually no statistical heterogeneity (P = 0.93, I(2) = 0%). Various subgroup and sensitivity analyses showed similar results. However, the total number of patients enrolled in these studies was small (n = 138). No significant adverse events were recorded in any of the studies and not enough data were available to pool the other secondary outcomes for meta-analysis.

AUTHORS' CONCLUSIONS

No evidence was found that supports the use of omega 3 fatty acids for maintenance of remission in UC. Further studies using enteric coated capsules may be justified.

New onset of atrial fibrillation after introduction of azathioprine in ulcerative colitis: case report and review of the literature

CASE REPORT

We present the case of a 52-year-old man with steroid-dependent ulcerative colitis, needing immunosuppressive therapy with azathioprine. The drug had been started 3 years earlier, but stopped after a few months because the patient reported palpitations, lipothymia, nausea and vomiting. Given the continued steroid-dependent ulcerative colitis and the lack of clinical documentation about a reaction with a dubious relationship to azathioprine, we decided to rechallenge the patient with the drug under clinical monitoring and after informed consent. After starting 50 mg of azathioprine, the patient showed general malaise, nausea and vomiting. An ECG showed atrial fibrillation, and the patient reported that the symptoms were similar to those previously experienced.

DISCUSSION

We have found two other cases of similar onset of atrial fibrillation after azathioprine use, although some confounding elements in these episodes make the possible causal relationship between the drug and this adverse event uncertain.

Current Medical Therapy for Chronic Inflammatory Bowel Diseases

Chronic idiopathic inflammatory bowel diseases (IBD) include Crohn's disease (CD), ulcerative colitis (UC), and colonic IBD type unclassified (IBDU). This article focuses upon current medical therapies for adult CD and UC, and is organized according to therapy for the corresponding disease type, stage, and severity.

Inflammatory bowel disease: clinical aspects and established and evolving therapies

Crohn's disease and ulcerative colitis are two idiopathic inflammatory bowel disorders. In this paper we discuss the current diagnostic approach, their pathology, natural course, and common complications, the assessment of disease activity, extraintestinal manifestations, and medical and surgical management, and provide diagnostic and therapeutic algorithms. We critically review the evidence for established (5-aminosalicylic acid compounds, corticosteroids, immunomodulators, calcineurin inhibitors) and emerging novel therapies--including biological therapies--directed at cytokines (eg, infliximab, adalimumab, certolizumab pegol) and receptors (eg, visilizumab, abatacept) involved in T-cell activation, selective adhesion molecule blockers (eg, natalizumab, MLN-02, alicaforsen), anti-inflammatory cytokines (eg, interleukin 10), modulation of the intestinal flora (eg, antibiotics, prebiotics, probiotics), leucocyte apheresis and many more monoclonal antibodies, small molecules, recombinant growth factors, and MAP kinase inhibitors targeting various inflammatory cells and pathways. Finally, we summarise the practical aspects of standard therapies including dosing, precautions, and side-effects.

Management of inflammatory bowel disease in adults

Optimal care of the inflammatory bowel diseases, Crohn's disease and ulcerative colitis, requires a broad understanding of disease pathophysiology and therapeutic alternatives. The goals of therapy are accurate diagnosis and timely treatment to both induce and maintain a clinical remission and improve patient quality of life. Most patients can be adequately treated using a combination or aminosalicylates, antibiotics, and corticosteroids, though many patients with Crohn's disease will require immunomodulators, such as azathioprine or 6-mercaptopurine. The development of novel biologic therapies, particularly infliximab, have dramatically improved our ability to medically manage more severe Crohn's disease and ulcerative colitis patients. This review will focus on the medical management of inflammatory bowel disease in adults.

Thiopurine treatment in inflammatory bowel disease: clinical pharmacology and implication of pharmacogenetically guided dosing

This review summarises clinical pharmacological aspects of thiopurines in the treatment of chronic inflammatory bowel disease (IBD). Current knowledge of pharmacogenetically guided dosing is discussed for individualisation of thiopurine therapy, particularly to avoid severe adverse effects. Both azathioprine and mercaptopurine are pro-drugs that undergo extensive metabolism. The catabolic enzyme thiopurine S-methyltransferase (TPMT) is polymorphically expressed, and currently 23 genetic variants have been described. On the basis of an excellent phenotype-genotype correlation for TPMT, genotyping has become a safe and reliable tool for determination of a patient's individual phenotype. Thiopurine-related adverse drug reactions are frequent, ranging from 5% up to 40%, in both a dose-dependent and -independent manner. IBD patients with low TPMT activity are at high risk of developing severe haematotoxicity if pharmacogenetically guided dosing is not performed. Based on several cost-benefit analyses, assessment of TPMT activity is recommended prior to thiopurine therapy in patients with IBD. The underlying mechanisms of azathioprine/mercaptopurine-related hepatotoxicity, pancreatitis and azathioprine intolerance are still unknown. Although the therapeutic response appears to be related to 6-thioguanine nucleotide (6-TGN) concentrations above a threshold of 230-260 pmol per 8 x 10(8) red blood cells, at present therapeutic drug monitoring of 6-TGN can be recommended only to estimate patients' compliance.Drug-drug interactions between azathioprine/mercaptopurine and aminosalicylates, diuretics, NSAIDs, warfarin and infliximab are discussed. The concomitant use of allopurinol without dosage adjustment of azathioprine/mercaptopurine leads to clinically relevant severe haematotoxicity due to elevated thiopurine levels. Several studies indicate that thiopurine therapy in IBD during pregnancy is safe. Thus, azathioprine/mercaptopurine should not be withdrawn in strictly indicated cases of pregnant IBD patients. However, breastfeeding is contraindicated during azathioprine/mercaptopurine therapy. Use of azathioprine/mercaptopurine for induction and maintenance of remission in corticosteroid-dependent or corticosteroid-refractory IBD, particularly Crohn's disease, is evidence based. To improve response rates in thiopurine therapy of IBD, comprehensive analyses including metabolic patterns and genome-wide profiling in patients with azathioprine/mercaptopurine treatment are required to identify novel candidate genes.

Relationship between 6-mercaptopurine dose and 6-thioguanine nucleotide levels in patients with inflammatory bowel disease

BACKGROUND

6-Thioguanine nucleotides (6-TGN) are active metabolites of azathioprine (AZA) and 6-mercaptopurine (6MP). Higher remission rates have been observed in patients with higher 6-TGN levels. However, many physicians prescribe AZA/6MP using milligrams per kilogram (mg/kg) dosing regimens without measuring 6-TGN levels. The aim of this study was to examine the association between 6MP dose and 6-TGN levels.

METHODS

We conducted a cross-sectional study of patients treated for inflammatory bowel disease (IBD) with AZA or 6MP, whose 6-TGN levels were measured. Patients with low or intermediate thiopurine methyl transferase (TPMT) activity were excluded. AZA dose was converted to 6MP equivalents. The relationship between dose and 6-TGN levels was assessed with the Spearman correlation coefficient. We used logistic regression to assess the relationship between dose and 6-TGN levels of >230 pmol/8 x 10(8).

RESULTS

In this study, 155 patients met our inclusion criteria (median dose, 1.01 +/- 0.40; range, 0.61-1.41 mg/kg). There was a weak correlation between 6-TGN levels and the absolute dose (rho = 0.18, P = 0.04) and the dose in mg/kg (rho = 0.19, P = 0.03). The correlation between mg/kg dosage and 6-TGN levels was slightly stronger in those using concomitant 5-aminosalicylate (5-ASA) medications (rho = 0.24, P = 0.02). Compared with <1.0 mg/kg per day, doses of > or =1.5 mg/kg per day were strongly associated with 6-TGN levels of >230 pmol/8 x 10(8) RBC (adjusted odds ratio [OR] = 3.7, 95% confidence interval [CI] = 1.1-11.8). However, only 37% of patients receiving > or =1.0 mg/kg per day had 6-TGN levels of >230 pmol/8 x 10(8) RBC.

CONCLUSIONS

6MP dose is weakly associated with 6-TGN levels. The use of standard mg/kg dosing regimens will result in low 6-TGN levels in most patients.

Drug insight: aminosalicylates for the treatment of IBD

Sulfasalazine and mesalazine (also known as mesalamine; 5-aminosalicylic acid) preparations have for many years been used for the treatment of IBD (i.e. ulcerative colitis and Crohn's disease), for both active disease and the control of remission. It has also been suggested that mesalazine is a chemoprophylactic agent that protects against the development of colorectal cancer. This Review focuses on the latest clinical evidence for the use of these aminosalicylates for the treatment of IBD, and concludes that sulfasalazine and mesalazine are useful for the treatment of both active and quiescent ulcerative colitis, whereas they have no clinical effect on either active or inactive Crohn's disease. Furthermore, evidence is lacking that mesalazine per se is a chemoprophylactic agent.

Review article: steroid resistance in inflammatory bowel disease - mechanisms and therapeutic strategies

BACKGROUND

Steroid resistance in inflammatory bowel disease presents a difficult clinical challenge. The advent of biological therapies coupled with an increasing understanding of the pathogenesis of inflammatory bowel disease has provided new therapeutic options.

METHODS

We review the available literature of the mechanisms behind steroid resistance. In addition, we outline some of the options available for treating those patients who fail to respond adequately to glucocorticoids.

RESULTS

Approximately 30% of patients prescribed glucocorticoids will not achieve clinical remission. Many such patients are offered immunosuppressive or, recently, biological agents. However, these agents are ineffective in a large proportion of patients. Immunosuppressive agents only bring 40-60% of patients into remission, and biological agents typically induce remission in just 40% of patients. In this review, the possible explanations for glucocorticoid resistance are discussed. Recent evidence suggests that in many patients it is mediated by interleukin-2. Basiliximab, a biological agent that interrupts interleukin-2 signalling, has shown significant benefit in early clinical studies.

CONCLUSIONS

Patients who fail to respond to steroid therapy should have alternative agents introduced in a timely fashion. Steroid refractory inflammatory bowel disease remains a difficult condition to treat, but new therapies and managements are emerging.

Inflammatory bowel disease: past, present, and future

Crohn's disease and ulcerative colitis, collectively known as the inflammatory bowel diseases (IBD), are largely diseases of the twentieth century, and are associated with the rise of modern, Westernized industrial society. Although the causes of these diseases remain incompletely understood, the prevailing model is that the intestinal flora drives an unmitigated intestinal immune response and inflammation in the genetically susceptible host. A review of the past and present of these diseases shows that detailed description preceded more fundamental elucidation of the disease processes. Working out the details of disease pathogenesis, in turn, has yielded dividends in more focused and effective therapy for IBD. This article highlights the key descriptions of the past, and the pivotal findings of current studies in disease pathogenesis and its connection to medical therapy. Future directions in the IBD will likely explicate the inhomogeneous causes of these diseases, with implications for individualized therapy.

Post-colonoscopic Listeria septicemia in ulcerative colitis during immunosuppressive therapy

A 78-year-old man who had been diagnosed with ulcerative colitis was admitted because of uncontrolled severe, frequent, bloody diarrhea. He was treated with immunosuppressive therapy that included corticosteroid and azathioprine. Colonoscopy was used to assess disease activity. This revealed that the mucosa of his digestive tract from the rectum to the ileum was damaged. He developed a high-grade fever soon after colonoscopy. Blood culture demonstrated Listeria monocytogenes. Treatment was changed to intravenous ampicillin for 20 days. His general body symptoms, including the bloody diarrhea, improved after treatment. We assume that the colonoscopy induced Listeria monocytogenes septicemia through bacterial translocation in this patient.

Azathioprine and mesalazine-induced effects on the mucosal flora in patients with IBD colitis

BACKGROUND

The impact of azathioprine and 5-aminosalicylic acid (5-ASA) on the innate immunity and mucosal flora is unknown. The study investigated the influence of IBD treatment on the concentrations and spatial organization of mucosal bacteria using fluorescence in situ hybridization with 16s r-RNA targeting probes.

METHODS

We prospectively investigated colonoscopic biopsies from five groups of 20 subjects each: patients with ulcerative or indeterminate colitis treated with azathioprine (group 1), azathioprine and 5-ASA (group 2), 5-ASA (group 3), untreated IBD (group 4), and healthy controls.

RESULTS

The elevated numbers of leukocytes in mucus of IBD patients were reduced nearly to norm in patients treated with azathioprine alone. In contrast, 5-ASA therapy had no influence on mucus leukocyte migration and was associated with the lowest concentrations of mucosal bacteria of all IBD groups. The suppressed migration of leukocytes in azathioprine-treated patients was accompanied by a 28-fold higher concentration of mucosal bacteria when compared with the 5-ASA group or a 1000-fold increase when compared with healthy controls. The percent of the epithelial surface covered with adherent bacteria (P < 0.001) and the amenability of mucosal bacteria (P = 0.01) were also significantly increased in the azathioprine-treated group compared with all other IBD groups. The patients receiving both 5-ASA and azathioprine did not differ statistically from untreated IBD patients either in mucus leukocyte migration or in bacterial concentrations.

CONCLUSIONS

Azathioprine and 5-ASA induce opposite effects on the mucus barrier. Concomitant therapy of 5-ASA and azathioprine mutually neutralizes the effects of both on the mucosal flora and the barrier function.

Biological therapy in the management of recent-onset Crohn's disease: why, when and how?

Crohn's disease is a chronic inflammatory bowel disease that may involve any part of the gastrointestinal tract. Conventional therapy consists of corticosteroids, azathioprine or methotrexate, but the clinical management of Crohn's disease is significantly hampered by adverse effects. With the introduction of biological agents (such as infliximab), the goals of therapy have advanced, including induction of remission with bowel healing as well as reduction in the rate of complications, surgeries and mortality. Current therapy for moderate to severe Crohn's disease is based on 'step-up' algorithms, which initiate treatment with corticosteroids followed by immunomodulatory agents, and defer therapy with biological agents until patients become refractory to conventional therapeutics. Recently, it has been shown that induction therapy with infliximab and azathioprine in recent-onset Crohn's disease (i.e. 'top-down' approach) is superior to current step-up algorithms to induce clinical remission. The underlying molecular mechanisms responsible for these differences in clinical outcome remain to be defined. Experimental studies have demonstrated that corticosteroids are able to induce impaired apoptosis of immune cells, including T cells and dendritic cells, resulting in loss of tolerance and subsequent autoimmunity. Further research will have to determine whether corticosteroid therapy augments the mechanism of loss of tolerance in Crohn's disease, which could complicate future clinical management.

Insights in immunomodulatory therapies for ulcerative colitis and Crohn's disease

Immunomodulators are a class of drugs that attenuate the underlying inflammatory processes of Crohn's disease (CD) and ulcerative colitis (UC), the two major inflammatory bowel diseases (IBD). These agents play a prominent role in the management of refractory and steroid-dependent IBD. The immunomodulatory drugs in the IBD arsenal include azathioprine, 6-mercaptopurine, methotrexate, cyclosporine, and tacrolimus. Azathioprine and 6-mercaptopurine are considered first-line immunosuppressants due to their proven efficacy in both CD and UC and their safety profile, whereas cyclosporine occupies a niche as a surgery-sparing agent in the acute management of severe, steroid-refractory UC. Immunomodulators also appear to have a role as adjunctive therapy when used with infliximab or other biologic agents to reduce immunogenicity. Although data have been limited to observational studies, azathioprine and 6-mercaptopurine may be used during pregnancy.