Topical tacrolimus in the treatment of perianal Crohn's disease: exploratory randomized controlled trial

Advancing immunotherapy using biomaterials to control tissue, cellular, and molecular level immune signaling in skin

Immunotherapies have been transformative in many areas, including cancer treatments, allergies, and autoimmune diseases. However, significant challenges persist in extending the reach of these technologies to new indications and patients. Some of the major hurdles include narrow applicability to patient groups, transient efficacy, high cost burdens, poor immunogenicity, and side effects or off-target toxicity that results from lack of disease-specificity and inefficient delivery. Thus, there is a significant need for strategies that control immune responses generated by immunotherapies while targeting infection, cancer, allergy, and autoimmunity. Being the outermost barrier of the body and the first line of host defense, the skin presents a unique immunological interface to achieve these goals. The skin contains a high concentration of specialized immune cells, such as antigen-presenting cells and tissue-resident memory T cells. These cells feature diverse and potent combinations of immune receptors, providing access to cellular and molecular level control to modulate immune responses. Thus, skin provides accessible tissue, cellular, and molecular level controls that can be harnessed to improve immunotherapies. Biomaterial platforms - microneedles, nano- and micro-particles, scaffolds, and other technologies - are uniquely capable of modulating the specialized immunological niche in skin by targeting these distinct biological levels of control. This review highlights recent pre-clinical and clinical advances in biomaterial-based approaches to target and modulate immune signaling in the skin at the tissue, cellular, and molecular levels for immunotherapeutic applications. We begin by discussing skin cytoarchitecture and resident immune cells to establish the biological rationale for skin-targeting immunotherapies. This is followed by a critical presentation of biomaterial-based pre-clinical and clinical studies aimed at controlling the immune response in the skin for immunotherapy and therapeutic vaccine applications in cancer, allergy, and autoimmunity.

Pharmacological Therapies for the Management of Fistulizing Crohn's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Fistulas are a debilitating complication of Crohn's disease [CD]. We conducted a systematic review to assess the efficacy of medical therapies for fistulizing CD.

METHODS

MEDLINE, Embase, and CENTRAL were searched on May 26, 2022, for randomized controlled trials [RCTs] of pharmacological therapy in adults with fistulizing CD. The primary outcome was induction and maintenance of fistula response. Pooled risk ratios [RRs] and 95% confidence intervals [CIs] were calculated. GRADE was used to assess the certainty of evidence.

RESULTS

Thirty-eight RCTs were included. Nineteen trials [50%] exclusively involved perianal fistula. The remaining studies included some participants with non-perianal fistula. Pooled RRs for anti-tumour necrosis factor [TNF] agents were not statistically significant for induction [RR 1.36, 95% CI 0.97-1.91] or maintenance of fistula response [RR 1.48, 95% CI 0.97-2.27]. However, in a sensitivity analysis of studies with fistula response as the primary outcome, anti-TNFs were superior to placebo for induction [RR 1.94, 95% CI 1.10-3.41] and maintenance [RR 1.88, 95% CI 1.23-2.88] of fistula response. Oral small molecules [RR 2.56, 95% CI 1.18-5.53] and mesenchymal stem cell [MSC] therapy [RR 1.26, 95% CI 1.01-1.57] were effective for induction of fistula response. Ustekinumab was associated with maintenance of fistula response [RR 1.80, 95% CI 1.04-3.11]. Vedolizumab was not superior to placebo. The certainty of evidence ranged from very low to moderate.

CONCLUSION

Very low- to moderate-certainty evidence suggests that anti-TNF therapy, oral small molecules, ustekinumab, and MSCs are effective for perianal fistulizing CD. Dedicated fistula studies evaluating biologics and small molecules are needed.

Management of Perianal Fistulizing Crohn's Disease

Perianal fistulizing Crohn's disease (CD) represents a severe phenotype of CD that is associated with significant morbidity and reduction in quality of life. Perianal fistulizing CD is caused by a complex interplay of genetic predisposition, immune dysregulation, gut dysbiosis, and various unknown physiological and mechanical factors. A multidisciplinary approach is hence required for optimal management . A detailed anatomical description and classification of perianal fistula, including comprehensive clinical, endoscopic, and radiological diagnostic workup, is an important prerequisite to treatment. For simple perianal fistulas, use of antibiotics and immunomodulators, with or without fistulotomy, are appropriate measures. The medical management of complex perianal fistula, on the other hand, requires adequate control of infection before initiation of therapy with immunomodulators. In active complex perianal fistula, anti-tumor necrosis factors remain the most accepted therapy, with concomitant use of antibiotics or immunomodulators enhancing the efficacy. For patients refractory to anti-tumor necrosis factors, treatment with anti-integrins, anti-interleukins, and small molecules is being evaluated. Mesenchymal stem cells, hyperbaric oxygen therapy, and exclusive enteral nutrition have also been investigated as adjunct therapies. Despite the expansion of the medical armamentarium, a large proportion of the patients require surgical interventions. In this review, we provide an up-to-date overview of the pathophysiology, clinical presentation, diagnosis, and medical management of perianal fistulizing CD. A brief overview of the surgical management of perianal fistulizing CD is also provided.

Management of Perianal Crohn's Disease

Perianal Crohn's disease affects 25%-35% of patients with Crohn's disease and has proven to be one of the most difficult complications of the disease to treat. Patients with perianal Crohn's disease have lower health-related quality of life scores typically related to pain and fecal incontinence. In addition, patients with perianal Crohn's disease have higher rates of hospitalizations, surgeries, and overall healthcare costs. A multidisciplinary approach is necessary for the successful management of Crohn's disease with perianal fistula. Medical management is required to treat the underlying immune dysregulation to heal the luminal inflammation and the inflammation within the fistula tracts. Current options for medical therapy include biologics, dual therapy with thiopurines, therapeutic drug monitoring, and a close follow-up. Surgical management is critical to drain abscesses before immunosuppressive therapy and place setons when appropriate. Once the patient's inflammatory burden is well managed, definitive surgical therapies including fistulotomies, advancement flaps, and ligation of intersphincteric fistula tract procedures can be considered. Most recently, the use of stem cell therapy in the treatment of perianal fistula has given new hope to the cure of perianal fistula in Crohn's disease. This review will outline the most current data in the medical and surgical management of perianal Crohn's disease.

Network meta-analysis: efficacy and safety of treatments for fistulising Crohn's disease

INTRODUCTION

Fistulas are a debilitating complication of Crohn's disease and treatment options remain limited. There is a lack of head-to-head comparisons between treatments. To our knowledge, this is the first network meta-analysis on the efficacy of medical therapies in achieving fistula remission and maintenance of fistula closure in Crohn's disease.

METHODS

Biomedical databases and the Cochrane Central Registry were searched between 1978 and 2022 for randomized controlled trials (RCTs) reporting on treatments. A network meta-analysis was performed using the frequentist model with pooled relative risks (RRs) and P -scores used to rank treatments.

RESULTS

Twenty-five RCTs were included for analysis with 2239 patients included. At the 16-24 week time point, infliximab produced the only statistically significant result with the 5 mg/kg dose proving the most effective [RR, 2.30; 95% confidence interval (CI), 1.40-3.77]. At 44 weeks, ustekinumab was found to be most superior with it being 2.38 times (RR, 2.38; 95% CI, 1.24-4.56) more superior to placebo, with adalimumab (RR, 2.06; 95% CI, 1.06-3.99) and infliximab 5 mg/kg (RR, 1.68; 95% CI, 1.03-2.75) also producing a statistically significant result.

CONCLUSION

Despite infliximab being favoured in international guidelines for the treatment of perianal fistulising Crohn's disease, biologics such as ustekinumab, vedolizumab and adalimumab show promising results.

Cutaneous Manifestations of Inflammatory Bowel Disease: A Basic Overview

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal (GI) tract that is subdivided into Crohn's disease (CD) and ulcerative colitis (UC). CD is characterized by involvement of the entire GI tract, while UC mainly affects the distal GI tract. Moreover, both CD and UC can present with extraintestinal manifestations (EIMs) of the disease affecting multiple organ systems including the hepatobiliary tract, kidney, bones, eyes, joints, and skin. These complications can cause significant morbidity and negatively impact the quality of life for IBD patients. Although the pathogenesis of EIMs is not clearly elucidated, it is postulated that the diseased GI mucosa similarly stimulates excess immune responses at the extraintestinal sites. Cutaneous EIMs occur in up to 15% of patients with IBD, often predating their IBD diagnosis. They are categorized into (1) specific, (2) reactive, (3) associated, and (4) treatment-induced. Here, we review the epidemiological, clinical, diagnostic, and histologic features of the most commonly described cutaneous EIMs of IBD along with their respective treatment options.

Anorectal Strictures in Complex Perianal CD: How to Approach?

Anorectal strictures are a notoriously difficult to treat phenotype of perianal Crohn's disease. Quality of life is diminished due to ongoing pain, incontinence, difficulty with stool evacuation, and recurrent medical and surgical treatments. Medical therapy is aimed at treating luminal disease and mucosal ulceration to prevent worsening of fibrosis. Clinical examination and endoscopic intervention can be used for serial dilations of strictures. Unfortunately, despite optimal medical therapy and endoscopic intervention with serial anal dilations, surgery with intestinal diversion or proctocolectomy may be required as part of the treatment algorithm in a significant proportion of patients.

Rectovaginal Fistula in Crohn's Disease: When and How to Operate?

Rectovaginal fistula (RVF) occurring during the course of Crohn's disease (CD) constitutes a therapeutic challenge and is characterized by a high rate of recurrence. To optimize the outcome of CD-related RVF repair, the best conditions for correct healing should be obtained. Remission of CD should be achieved with no active proctitis, the perianal CD activity should be minimized, and local septic complications should be controlled. The objective of surgical repair is to close the fistula tract with minimal recurrence and functional disturbance. Several therapeutic strategies exist and the approach should be tailored to the anatomy of the RVF and the quality of the local supporting tissues. Herein, we review the medical and surgical management of CD-related RVF.

Endpoints for Perianal Crohn's Disease Trials: Past, Present and Future

BACKGROUND AND AIMS

Since the 1980s, many studies have evaluated the efficacy of therapies to improve the outcomes of patients with perianal Crohn's disease. We performed a systematic review to describe the evolution of endpoints in perianal fistulizing Crohn's disease. Efficacy outcomes, definitions and measurement tools were assessed.

METHODS

Electronic databases were searched up to November 1, 2020. All published randomized placebo-controlled trials enrolling patients with perianal fistula and Crohn's disease were eligible for inclusion. Ongoing randomized clinical trials were also described.

RESULTS

Nineteen randomized controlled trials were included. Clinical efficacy endpoints were reported in all trials. Clinical response was the most frequent primary endpoint [6/19 studies, 31.6%], followed by clinical remission in four studies [21%]. Clinical response was defined as closure of at least 50% of fistulas, while remission was defined as closure of all fistulas. A combined clinical and radiological primary endpoint was used to assess fistula healing in four studies [21%]. The Perianal Disease Activity Index was a primary endpoint in only one study [5.5%]. In addition, eight ongoing controlled trials were identified. Combined clinical and radiological remission was the most frequent primary endpoint in these studies [4/8, 50%].

CONCLUSION

In this systematic review, significant changes in outcomes used in randomized clinical trials of perianal Crohn's disease were observed. Radiological endpoints are increasingly used in perianal fistulizing Crohn's disease trials.

Role of topical tacrolimus in the management of proctitis, perianal manifestations in Crohn's disease, and chronic pouchitis: a systematic review

Several published studies have evaluated the safety and effectiveness of oral and intravenous tacrolimus for the management of patients with inflammatory bowel disease (IBD). However, little is known about the effectiveness of topical tacrolimus in this patient population. The aim of this systematic review was to evaluate the current state of literature to evaluate the safety and effectiveness of rectal administration of topical tacrolimus, in the form of suppository, ointment, and/or enema in patients with ulcerative proctitis, perianal Crohn's disease (CD), and chronic refractory pouchitis. Electronic database searches were conducted in international databases since their inception until February 2020. Study subjects were categorized into three groups: topical tacrolimus for patients with proctitis, perianal CD, and chronic refractory pouchitis. The primary end point of this study was the remission rate. Secondary end points were response rate and the incidence of AEs. Eleven studies were included in the final assessment in this systematic review. This provided information from 188 patients. Tacrolimus was administered topically as suppositories, ointment, or enema. Clinical remission was achieved in 57.1%, 57.14%, and 70.0% in patients with proctitis, fistulizing perianal CD, and chronic pouchitis. The most commonly reported side effect was perianal itching and burning. Reversible nephrotoxicity occurred in a single patient. No clear correlation was found between blood levels and clinical outcomes. Topical tacrolimus is effective for a subset of patients with IBD. The adverse effects were minimal and tolerable. Well-designed randomized clinical trials are warranted to establish the appropriate dose and administration method.

3D Printed Tacrolimus Rectal Formulations Ameliorate Colitis in an Experimental Animal Model of Inflammatory Bowel Disease

The aim of this study was to fabricate novel self-supporting tacrolimus suppositories using semisolid extrusion 3-dimensional printing (3DP) and to investigate their efficacy in an experimental model of inflammatory bowel disease. Blends of Gelucire 44/14 and coconut oil were employed as lipid excipients to obtain suppository formulations with self-emulsifying properties, which were then tested in a TNBS (2,4,6-trinitrobenzenesulfonic acid) induced rat colitis model. Disease activity was monitored using PET/CT medical imaging; maximum standardized uptake values (SUVmax), a measure of tissue radiotracer accumulation rate, together with body weight changes and histological assessments, were used as inflammatory indices to monitor treatment efficacy. Following tacrolimus treatment, a significant reduction in SUVmax was observed on days 7 and 10 in the rat colon sections compared to non-treated animals. Histological analysis using Nancy index confirmed disease remission. Moreover, statistical analysis showed a positive correlation (R2 = 71.48%) between SUVmax values and weight changes over time. Overall, this study demonstrates the effectiveness of 3D printed tacrolimus suppositories to ameliorate colitis and highlights the utility of non-invasive PET/CT imaging to evaluate new therapies in the preclinical area.

Management of Isolated Anal Strictures in Crohn's Disease

BACKGROUND

Anorectal stricturing is a particularly morbid manifestation of Crohn's disease resulting in a diminished quality of life related to pain, incontinence, and recurrent operative interventions.

OBJECTIVE

To determine the role of medical therapy, endoscopic dilation, and surgical intervention for the treatment of isolated anorectal stricturing.

DATA SOURCES

An organized search of MEDLINE, PubMed, EMBASE, Scopus, and the Cochrane Database of Collected Reviews was performed from January 1, 1990 through May 1, 2020.

STUDY SELECTION

Full text papers which included management of isolated anorectal strictures in the setting of Crohn's disease.

INTERVENTION(S)

Medical and surgical management.

MAIN OUTCOME MEASURES

Symptomatic relief, need for proctocolectomy.

RESULTS

Our search identified a total of 553 papers; after exclusion based on title (n = 430) and abstract (n = 47), 76 underwent full text review with 65 relevant to the management of anorectal strictures. A summary of the retrospective reports suggests that medical therapy can help control luminal inflammation, but fibrosis may ultimately set in resulting in a need for endoscopic or surgical intervention. Surgical options are limited in the anal canal due to inflammation and ulceration and concomitant perianal fistulizing disease. While fecal diversion can provide symptomatic relief, successful restoration of intestinal continuity remains uncommon and most patients ultimately undergo a total proctocolectomy with end ileostomy.

LIMITATIONS

Limited literature published, all retrospective in nature.

CONCLUSIONS

Despite significant advances in medical and surgical therapy in Crohn's disease over the last decades, there is clearly an unmet need in the management of anorectal strictures in Crohn's disease.

Therapeutic Efficacy and Adverse Events of Tacrolimus in Patients with Crohn's Disease: Systematic Review and Meta-Analysis

BACKGROUND

Only a few randomized controlled trials (RCTs) and some uncontrolled trials have reported the efficacy and adverse events (AEs) of tacrolimus (Tac) in patients with refractory Crohn's disease (CD). The aim of this study was to undertake a systematic review and meta-analysis of the therapeutic efficacy and AEs of Tac in patients with CD.

METHODS

We investigated studies reporting the therapeutic efficacy of Tac in patients with CD from 1950 until December 2017. Study subjects were categorized into three groups: systemic administration of Tac for patients with luminal CD (Group 1); systemic administration of Tac for patients with perianal CD (Group 2); and topical administration of Tac for patients with localized CD (Group 3). The primary endpoint of this study was the remission rate. Secondary endpoints were partial response rate, factors related to remission, and the incidence of AEs.

RESULTS

The remission rate of Group 1, 2, and 3 was 37.1, 32.0, and 22.7%, respectively. The partial response rate of those was 42.3, 42.9, and 44.3%, respectively. In addition, the incidence of AEs of those was 50.9, 65.5, and 40.0%, respectively. No life-threatening AEs were observed in any study.

CONCLUSION

This systematic review and meta-analysis demonstrated that Tac therapy was effective for subpopulation of CD patients and that the incidence of AEs was tolerable. Therefore, Tac therapy should be considered an option for patients with CD. However, there have been few well-designed RCTs on this subject and further studies are required.

Advances in research of tacrolimus for treatment of inflammatory bowel disease

Traditional drugs for inflammatory bowel disease (IBD) include aminosalicylic acid preparations, glucocorticoids, and immunosuppressive agents such as thiopurine and cyclosporine. In recent ten years, the application of anti-tumor necrosis factor (anti-TNF) drugs has greatly improved the clinical remission of patients with IBD, but there are still some problems, such as no response, intolerance, and recurrence after withdrawal. In recent years, tacrolimus, as a new powerful immunosuppressive agent, has been used as a second-line therapeutic drug for IBD. At present, the tacrolimus induced short-term remission effect in IBD is relatively obvious, and it has been gradually used for treatment of IBD refractory to traditional drugs or anti-TNF drugs. A few studies have found that tacrolimus can be used safely for a long time under proper monitoring. However, there is little evidence of long-term efficacy and safety. In this paper, we review the latest advances in the treatment of IBD with tacrolimus and make a comparison with anti-TNF drugs.

Systematic review: outcomes and adverse events from randomised trials in Crohn's disease

BACKGROUND

The suitability of disease activity indices has been challenged, with growing interest in objective measures of inflammation.

AIM

To undertake a systematic review of efficacy and safety outcomes in placebo-controlled randomised controlled trials (RCTs) of patients with Crohn's disease.

METHODS

MEDLINE, EMBASE, CINAHL and Cochrane Library were searched until November 2015, for RCTs of adult Crohn's disease patients treated with medical or surgical therapies. Data on efficacy and safety outcomes, end-point definitions, and measurement instruments were extracted and stratified by publication date (pre-2009 and 2009 onwards).

RESULTS

One hundred and eighty-one RCTs (110 induction and 71 maintenance) were identified, including 23 850 patients. About 92.3% reported clinical efficacy endpoints. The Crohn's Disease Activity Index (CDAI) dominated, defining clinical response or remission in 63.5% of trials (35 definitions of response or remission). CDAI < 150 was the commonest endpoint, but reporting reduced between periods (46.4%-41.1%), whilst use of CDAI100 increased (16.8%-30.4%). Fistula studies most commonly reported fistula closure (9, 90.0%). Reporting of biomarker, endoscopy and histology endpoints increased overall (33.3%-40.6%, 14.4%-30.4% and 3.2%-12.5%, respectively), but were heterogeneous and rarely reported in fistula trials. Patient-reported outcome measures were reported in 41.4% of trials and safety endpoints in 35.4%. Many of the common adverse events relate to disease exacerbation or treatment failure.

CONCLUSIONS

Trial endpoints vary across studies, over time and are distinct in fistula studies. Despite growth in reporting of objective measures of inflammation and in patient-reported outcome measures, there is a lack of standardisation. This confirms the need for a core outcome set for comparative effectiveness research in Crohn's disease.

The role of topical therapy for perianal fistulizing Crohn's disease: are we forgetting something?

INTRODUCTION

Rectal inflammation is the principal risk factor for the development of perianal fistulizing Crohn's disease. However, no topical therapy direct to rectal healing is discussed in European' guidelines. The aim of this systematic review was to evaluate the role of topical therapy in healing the rectal inflammation in Crohn's disease.

EVIDENCE ACQUISITION

A MEDLINE search of all studies published in English until December 2018 was conducted. Articles were identified using the strings "Crohn's disease and topical therapy" or "perianal Crohn's disease and topical therapy."

EVIDENCE SYNTHESIS

Contradictory results about the efficacy of topical metronidazole were present. No benefit from topical tacrolimus use was demonstrated. Mesalazine suppositories induced and maintained remission of rectal inflammation in 50% of patients with rectal Crohn's disease. Few data were available about the role of local therapy for the fistulous tract in Crohn's disease. Local mesenchymal stem cells therapy could be a promising new approach.

CONCLUSIONS

Due to the disappoint success rate of current strategy in perianal fistulizing Crohn's disease, the role of rectal inflammation as a causative factor and the fair success rate of topical therapy with mesalazine suppositories in the healing of rectal inflammation without relevant side effects, more studies are advisable in this field.

Management of anoperineal lesions in Crohn's disease: a French National Society of Coloproctology national consensus

The French National Society of Coloproctology established national recommendations for the treatment of anoperineal lesions associated with Crohn's disease. Treatment strategies for acute abscesses, active fistulas (active denovo and still active under treatment), fistulas in remission, and rectovaginal fistulas are suggested. Recommendations have been graded following the international recommendations, and when absent, professional agreement has been established. For each situation, practical algorithms have been drawn.

Clinical Practice Guideline for the Medical Management of Perianal Fistulizing Crohn's Disease: The Toronto Consensus

BACKGROUND

Fistulas occur in about 25% of patients with Crohn's disease (CD) and can be difficult to treat. The aim of this consensus was to provide guidance for the management of patients with perianal fistulizing CD.

METHODS

A systematic literature search identified studies on the management of fistulizing CD. The quality of evidence and strength of recommendations were rated according to the Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach. Statements were developed through an iterative online platform using a modified Delphi process, then finalized, and voted on by a group of specialists.

RESULTS

The quality of evidence for treatment of fistulizing CD was generally of very low quality, and because of the scarcity of good randomized controlled trials (RCTs), these consensus statements generally provide conditional suggestions (5 of 7 statements). Imaging and surgical consultations were recommended in the initial assessment of patients with active fistulizing CD, particularly those with complicated disease. Antibiotic therapy is useful for initial symptom control. Antitumor necrosis factor (anti-TNF) therapy was recommended to induce symptomatic response, and continued use was suggested to achieve and maintain complete remission. The use of concomitant immunosuppressant therapies may be useful to optimize pharmacokinetic parameters when initiating anti-TNF therapy. When there has been an inadequate symptomatic response to medical management strategies, surgical therapy may provide effective fistula healing for some patients.

CONCLUSIONS

Optimal management of perianal fistulizing CD requires a collaborative effort between gastroenterologists and surgeons and may include the evidence-based use of existing therapies, as well as surgical assessments and interventions when needed. 10.1093/ibd/izy247_video1izy247.video15978518763001.

Efficacy of Medical Therapies for Fistulizing Crohn's Disease: Systematic Review and Meta-analysis

BACKGROUND & AIMS

Fistulas are debilitating complications of Crohn's disease (CD) that affect up to 50% of patients. We conducted a systematic review and meta-analysis of randomized controlled trials to assess the efficacy of treatments for fistulizing CD.

METHODS

We searched publication databases from inception through December 13, 2016 for trials comparing the efficacy of a therapeutic agent (single or combination) with placebo or another active therapy in adult patients with any form of fistulizing CD. The Cochrane risk of bias tool was used to assess the methodological quality of trials; the overall quality of evidence was evaluated using GRADE. Primary outcomes included induction and maintenance of fistula response and remission. Pooled risk ratios (RRs) and 95% CIs were calculated for each outcome.

RESULTS

We analyzed data from 27 trials; most studies (21/27) focused on patients with perianal fistulizing CD. We found moderate-quality evidence to support the efficacy of tumor necrosis factor (TNF) antagonists (RR, 2.01; 95% CI, 1.36-2.97), particularly infliximab, ustekinumab (RR, 1.77; 95% CI, 0.93-3.37), and mesenchymal stem cell therapy (RR, 1.31; 95% CI, 0.98-1.73) for induction of fistula remission. We found low-quality evidence for the efficacy of vedolizumab and immunosuppressives. There was also low-quality evidence to support the efficacy of combination therapy with TNF antagonists and antibiotics vs a TNF antagonist alone.

CONCLUSION

In a systematic review and meta-analysis of 27 controlled trials, we found TNF antagonists to be effective for induction and maintenance of perianal fistula response and remission. There are few data on the effects on internal fistulae. Further studies are needed, particularly for ustekinumab, vedolizumab, and stem cell therapies, in patients with fistulizing CD.

Pharmacological Approach to the Management of Crohn's Disease Patients with Perianal Disease

Perianal localization of Crohn's disease involves significant morbidity, affects quality of life and results in an increased use of healthcare resources. Medical and surgical therapies contribute to its management. The objective of this review is to address the current understanding in the management of perianal Crohn's disease, with the main focus in reviewing pharmacological therapies, including stem cells. In complex fistulas, once local sepsis has been controlled by surgical drainage and/or antibiotics, anti-TNF drugs (infliximab, adalimumab) are the first-line therapy, with or without associated immunomodulators. Combining surgery and anti-TNF therapy has additional benefits for healing. However, response is inadequate in up to half of cases. A possible role of new biological drugs in this context (vedolizumab, ustekinumab) is an area of ongoing investigation, as is the local application of autologous or allogeneic mesenchymal stem cells. These are non-hematopoietic multipotent cells with anti-inflammatory and immunomodulatory properties, the use of which may successfully treat refractory patients, and seem to be a promising and safe alternative to achieving fistula healing in Crohn's disease, without known systemic effects.

Clinical Practice Guideline for the Medical Management of Perianal Fistulizing Crohn's Disease: The Toronto Consensus

Background

Fistulas occur in about 25% of patients with Crohn's disease (CD) and can be difficult to treat. The aim of this consensus was to provide guidance for the management of patients with perianal fistulizing CD.

Methods

A systematic literature search identified studies on the management of fistulizing CD. The quality of evidence and strength of recommendations were rated according to the Grading of Recommendation Assessment, Development and Evaluation (GRADE) approach. Statements were developed through an iterative online platform using a modified Delphi process, then finalized, and voted on by a group of specialists.

Results

The quality of evidence for treatment of fistulizing CD was generally of very low quality, and because of the scarcity of good randomized controlled trials (RCTs), these consensus statements generally provide conditional suggestions (5 of 7 statements). Imaging and surgical consultations were recommended in the initial assessment of patients with active fistulizing CD, particularly those with complicated disease. Antibiotic therapy is useful for initial symptom control. Antitumor necrosis factor (anti-TNF) therapy was recommended to induce symptomatic response, and continued use was suggested to achieve and maintain complete remission. The use of concomitant immunosuppressant therapies may be useful to optimize pharmacokinetic parameters when initiating anti-TNF therapy. When there has been an inadequate symptomatic response to medical management strategies, surgical therapy may provide effective fistula healing for some patients.

Conclusions

Optimal management of perianal fistulizing CD requires a collaborative effort between gastroenterologists and surgeons and may include the evidence-based use of existing therapies, as well as surgical assessments and interventions when needed.

Medical and surgical management of perianal Crohn's disease

Crohn's disease is increasingly thought to encompass multiple possible phenotypes. Perianal manifestations account for one such phenotype and represent an independent disease modifier. In its more severe form, perianal Crohn's disease confers a higher risk of a severe and disabling disease course, relapses, hospital admissions and operations. This, in turn, imposes a considerable burden and disability on patients. Identification of the precise manifestation is important, as management is nuanced, with both medical and surgical components, and is best undertaken in a multidisciplinary setting for both diagnosis and ongoing treatment. The introduction of biologic medication has heralded a significant addition to the management of fistulizing perianal Crohn's disease in particular, albeit with modest results. It remains a very challenging condition to treat and further work is required to optimize management in this group of patients.

Perianal fistulizing Crohn's disease: pathogenesis, diagnosis and therapy

Perianal fistulizing Crohn's disease has a major negative effect on patient quality of life and is a predictor of poor long-term outcomes. Factors involved in the pathogenesis of perianal fistulizing Crohn's disease include an increased production of transforming growth factor β, TNF and IL-13 in the inflammatory infiltrate that induce epithelial-to-mesenchymal transition and upregulation of matrix metalloproteinases, leading to tissue remodelling and fistula formation. Care of patients with perianal Crohn's disease requires a multidisciplinary approach. A complete assessment of fistula characteristics is the basis for optimal management and must include the clinical evaluation of fistula openings, endoscopic assessment of the presence of proctitis, and MRI to determine the anatomy of fistula tracts and presence of abscesses. Local injection of mesenchymal stem cells can induce remission in patients not responding to medical therapies, or to avoid the exposure to systemic immunosuppression in patients naive to biologics in the absence of active luminal disease. Surgery is still required in a high proportion of patients and should not be delayed when criteria for drug failure is met. In this Review, we provide an up-to-date overview on the pathogenesis and diagnosis of fistulizing Crohn's disease, as well as therapeutic strategies.

Efficacy of Rectal Tacrolimus for Induction Therapy in Patients With Resistant Ulcerative Proctitis

BACKGROUND & AIMS

Resistant ulcerative proctitis can be extremely difficult to manage. Topically administered tacrolimus, however, may be effective in difficult-to-treat proctitis. This was a randomized, double-blind, placebo-controlled induction trial of rectal tacrolimus in patients with active ulcerative colitis.

METHODS

Eleven patients received rectal tacrolimus (0.5 mg/mL), and 10 placebo, for 8 weeks. The primary endpoint was clinical response by using the Mayo Clinic score.

RESULTS

A planned interim analysis after 20 patients had completed the study demonstrated highly significant differences between the groups and the study was closed because of ethical considerations with patients already recruited allowed to complete the study. The primary endpoint was met in 8 of 11 patients receiving rectal tacrolimus and 1 of 10 patients receiving placebo (73% vs 10%; P = .004). Of the secondary endpoints, 5 patients with rectal tacrolimus achieved clinical remission compared with none receiving placebo (45% vs 0%; P = .015). Mucosal healing at Week 8 was achieved in 8 patients receiving rectal tacrolimus compared with 1 (73% vs 10%) receiving placebo (P = .004). The Inflammatory Bowel Disease Questionnaire increased ≥16 points over baseline in 5 of the tacrolimus and 2 (45% vs 20%) of the placebo patients (P = .36). Finally, the average partial Mayo score was numerically lower in the tacrolimus-treated group compared with placebo at Week 2 (4.3 ± 0.74 vs 5.8 ± 0.64; P = .15) and Week 4 (3.7 ± 0.96 vs 5.8 ± 0.6; P = .08) but was significantly lower at Week 8 (3.3 ± 1.2 vs 6.7 ± 0.62; P = .01). There were no safety issues identified with rectal tacrolimus use.

CONCLUSIONS

Rectal tacrolimus was more effective than placebo for induction of a clinical response, clinical remission, and mucosal healing in resistant ulcerative proctitis (Clinicaltrials.gov registration: NCT01418131).

Fistulizing Crohn's Disease

Fistulas still represent one of the most important complications in patients with Crohn’s disease (CD). At least one third of CD patients suffer from fistulas during their disease course and amongst them longstanding remission of complex fistulas occurs only in about one third. So far, fistula pathogenesis is only partially understood. From a histopathological view, a fistula is a tube covered by flat epithelial cells. Current research suggests that the driving force for fistula development is epithelial-to-mesenchymal transition (EMT). Around the fistula, high levels of tumor necrosis factor (TNF), IL-13, and TGFβ can be detected and recent studies indicated an involvement of the intestinal microbiota. Fistula diagnosis requires clinical and surgical assessment, radiologic investigations, e.g., magnet resonance imaging and endoscopy. Routine medical treatment of fistulas includes antibiotics, immunosuppressives, and anti-TNF antibodies. There is no well-established role for calcineurin inhibitors in fistula treatment, corticosteroids appear to be even contra-productive. A promising novel approach might be the application of adipose tissue-derived or bone marrow-derived mesenchymal stem cells that have been studied recently. Due to insufficient efficacy of medical treatment and recurrence of fistulas, surgical interventions are frequently necessary. Further research is needed to better understand fistula pathogenesis aiming to develop novel treatment option for our patients.

Perianal Crohn's disease: challenges and solutions

Perianal Crohn’s disease affects a significant number of patients with Crohn’s disease and is associated with poor quality of life. The nature of the disease, compounded by presentation of various disease severities, has made the treatment of perianal Crohn’s disease difficult. The field continues to evolve with the use of both historical and contemporary solutions to address the challenges associated with it. The goal of this article is to review current literature regarding medical and surgical treatment, as well as the future directions of therapy.

The Gastroenterologist's Role in Management of Perianal Fistula

Perianal fistula occurs frequently in the Crohn disease population. Therapy for fistulas has changed through the years from primarily surgical management to multidisciplinary management among gastroenterologists, radiologists, and surgeons. Gastroenterologists play a role in assisting with diagnosis through endoscopic ultrasound and assessment of luminal disease activity, providing medical therapy including biologic therapy and antibiotics, and coordinating the multidisciplinary care with surgical and radiologic colleagues.

Norisoboldine, an alkaloid from Radix linderae, inhibits NFAT activation and attenuates 2,4-dinitrofluorobenzene-induced dermatitis in mice

CONTEXT

The nuclear factor of activated T-cells (NFAT) is a family of transcription factors, essential for T-cell activation. Norisoboldine (NOR), an isoquinoline alkaloid from Radix linderae, has been demonstrated to possess anti-inflammatory activity.

OBJECTIVE

This study examines NOR's effect on NFAT activation and its therapeutic potential for atopic dermatitis (AD).

MATERIALS AND METHODS

The transcriptional activity of NFAT was examined with luciferase reporter assay, using K562-luc cells, stimulated with 20 ng/mL PMA plus 1 μM ionomycin. NFAT dephosphorylation was examined by immuno-blotting in K562-luc cells and Jurkat cells. Interleukin-2 (IL-2) expression in Jurkat cells was examined by real-time PCR. A mouse model of dermatitis, induced by 2,4-dinitrochlorobenzene (DNCB), was used to test NOR's therapeutic potential for AD.

RESULTS

NOR, dose-dependently, inhibited PMA and ionomycin-induced NFAT reporter gene expression in K562-luc cells in the range of 2-50 μM. NOR also inhibited PMA and ionomycin-induced NFAT dephosphorylation in K562-luc cells and Jurkat cells. Consequently, NOR suppressed PMA plus ionomycin-induced IL-2 expression in Jurkat cells. The administration of NOR (10 mg/kg, i.p.), alleviated DNCB-induced dermatitis in mice, by the reduction of ear swelling and attenuation of inflammatory infiltration into ear tissue. Moreover, mRNA levels of INF-γ, TNF-α, IL-4 and IL-6 in ears of NOR-treated mice were reduced by 78.4, 77.8, 72.3 and 73.9%, respectively, compared with untreated controls.

DISCUSSION AND CONCLUSION

This study demonstrates that NOR inhibits NFAT activation in T-cells and alleviates AD-like inflammatory reaction in a DNCB-induced dermatitis model, highlighting NOR as a potential therapeutic agent for AD.

Systematic review of evidence and consensus on perianal fistula: an analysis of national and international guidelines

AIM

Treatment of perianal fistula has evolved with the introduction of new techniques and biologicals in Crohn's disease (CD). Several guidelines are available worldwide, but many recommendations are controversial or lack high-quality evidence. The aim of this work was to provide an overview of the current available national and international guidelines for perianal fistula and to analyse areas of consensus and areas of conflicting recommendations, thereby identifying topics and questions for future research.

METHOD

MEDLINE, EMBASE and PubMed were systematically searched for guidelines on perianal fistula. Inclusion was limited to papers in English less than 10 years old. The included topics were classified as having consensus (unanimous recommendations in at least two-thirds of the guidelines) or controversy (fewer than three guidelines commenting on the topic or no consensus) between guidelines. The highest level of evidence was scored as sufficient (level 3a or higher of the Oxford Centre for Evidence-based Medicine Levels of Evidence 2009, http://www.cebm.net/oxford-centre-evidence-based-medicine-levels-evidence-march-2009/) or insufficient.

RESULTS

Twelve guidelines were included and topics with recommendations were compared. Overall, consensus was present in 15 topics, whereas six topics were rated as controversial. Evidence levels varied from strong to lack of evidence.

CONCLUSION

Evidence on the diagnosis and treatment of perianal fistulae (cryptoglandular or related to CD) ranged from nonexistent to strong, regardless of consensus. The most relevant research questions were identified and proposed as topics for future research.

Immunomodulators for the treatment of Crohn's disease in adults: optimal use and prospects for future drug treatments

Crohn's disease (CD) requires treatment beyond symptoms by enabling and maintaining mucosal healing and therefore clinical remission. However, with the increasing use of biologics there have been safety concerns and there is a significant cost implication with the early use of biologics. Therefore, it is imperative that patients with severe/complicated disease or poor prognostic factors are treated with an aggressive strategy while all remaining patients should be treated in a step-up strategy. The potential for disease modification with thiopurines and methotrexate is debated in CD when they are used as a monotherapy. In this review we discuss existing and newer therapies that have recently been developed for CD. We will also provide an algorithm for current management of adult CD patients in routine clinical practice.

Modern Treatments and Stem Cell Therapies for Perianal Crohn's Fistulas

Crohn's disease (CD) is a complex disorder with important incidence in North America. Perianal fistulas occur in about 20% of patients with CD and are almost always classified as complex fistulas. Conventional treatment options have shown different success rates, yet there are data indicating that these approaches cannot achieve total cure and may not improve quality of life of these patients. Fibrin glue, fistula plug, topical tacrolimus, local injection of infliximab, and use of hematopoietic stem cells (HSC) and mesenchymal stem cells (MSC) are newly suggested therapies with variable success rates. Here, we aim to review these novel therapies for the treatment of complex fistulizing CD. Although initial results are promising, randomized studies are needed to prove efficacy of these approaches in curing fistulizing perianal CD.

Combining infliximab, anti-MAP and hyperbaric oxygen therapy for resistant fistulizing Crohn's disease

Background:

Fistulizing Crohn's disease (CD) presents a therapeutic challenge as fistulae are notoriously difficult to heal. Mycobacterium avium ss paratuberculosis (MAP) treatment in CD is gaining attention.

Aim:

We evaluated healing of CD fistula(e) using a novel combination therapy.

Study:

Nine consecutive patients who failed to heal fistulae on conventional treatment including anti-TNF, were treated with at least three doses of infliximab, 18–30 courses of hyperbaric oxygen therapy and anti-MAP antibiotics comprising rifabutin, clarithromycin and clofazimine.

Results:

All patients achieved complete healing of fistulae by 6–28 weeks and follow-up for mean 18 months.

Conclusion:

Combining infliximab, hyperbaric oxygen therapy and anti-MAP, seems to enable healing of recalcitrant fistulae and although a small case series, all nine patients achieved complete healing.

Lay abstract: Nine consecutive patients with Crohn's disease and fistulae were treated with a special combination of infliximab, numerous hyperbaric oxygen sessions and combined antibiotics including rifabutin, clofazimine and clarithromycin as the base antibiotic combination – called anti-Mycobacterium avium ss paratuberculosis (MAP) therapy. At between 6 weeks and 6 months all fistulae healed – included rectovaginal – so that the skin was dry and there was no discharge and no need to wear a pad. Their Crohn's symptoms of diarrhea, urgency and bleeding also resolved. Continuation with anti-MAP therapy alone maintained healing although one patient who ceased the anti-MAP therapy had a relapse.

Particular aspects of proctology for anoperineal lesions in Crohn's disease

All practitioners caring for patients with Crohn's disease (CD) must know all the various aspects of anoperineal lesions in this singular entity. Suppuration in CD does not follow the classic routes and spaces of diffusion and is often associated with endolumenal lesions that can evolve on their own. Abscesses and fistulas require specific medico-surgical management where seton drainage, staged operative and sphincter-sparing procedures have a dominant place. The variability of associated lesions and the particularly individualized efficacy of drugs call for case-by-case management, thus, making standardization and comparisons difficult. Recent therapeutic progress has led to modifications of the minimally invasive management policies practiced in the last decades.

An update on medical management on Crohn's disease

INTRODUCTION

The management of Crohn's disease (CD) is continuously evolving. New issues emerging from more recent studies could influence the decision-making process in clinical practice.

AREAS COVERED

The aim of this review article is to highlight critical issues on the management of CD, new evidence from clinical trials, long-term prospective studies and real life experience, beyond the current guidelines.

EXPERT OPINION

The role of mucosal healing in clinical practice is uncertain, clinical remission remains the primary end point. The timing for the definition of steroid-resistant CD should be considered between 2 and 4 weeks. Early treatment strategy with immunomodulators is effective for inducing remission but no controlled data are available regarding long-term outcome. Combination therapy (anti-TNFs agents and immunosuppressors) is more effective than single therapy but there is a lack of long-term data and an increased risk of malignancy. The effect of mesalazine, metronidazole and azathioprine in reducing postoperative recurrence is not clinically relevant; biologics are effective, but the duration of treatment is unknown. New drugs are under investigation in order to find exit strategy for patients who no longer respond to biologics. Combination therapy set on anti-TNF-α is until now the best option both to achieve fistula healing and avoid recurrence.

A global consensus on the classification, diagnosis and multidisciplinary treatment of perianal fistulising Crohn's disease

OBJECTIVE

To develop a consensus on the classification, diagnosis and multidisciplinary treatment of perianal fistulising Crohn's disease (pCD), based on best available evidence.

METHODS

Based on a systematic literature review, statements were formed, discussed and approved in multiple rounds by the 20 working group participants. Consensus was defined as at least 80% agreement among voters. Evidence was assessed using the modified GRADE (Grading of Recommendations Assessment, Development, and Evaluation) criteria.

RESULTS

Highest diagnostic accuracy can only be established if a combination of modalities is used. Drainage of sepsis is always first line therapy before initiating immunosuppressive treatment. Mucosal healing is the goal in the presence of proctitis. Whereas antibiotics and thiopurines have a role as adjunctive treatments in pCD, anti-tumour necrosis factor (anti-TNF) is the current gold standard. The efficacy of infliximab is best documented although adalimumab and certolizumab pegol are moderately effective. Oral tacrolimus could be used in patients failing anti-TNF therapy. Definite surgical repair is only of consideration in the absence of luminal inflammation.

CONCLUSIONS

Based on a multidisciplinary approach, items relevant for fistula management were identified and algorithms on diagnosis and treatment of pCD were developed.

Treatment of a Crohn's disease-related cutaneous facial lesion with topical tacrolimus

We report a case of an orofacial lesion in Crohn's disease successfully treated with tacrolimus ointment. A 22-year-old woman with Crohn's disease presented with a discharging lesion on the right side of her face. Intraorally, there was a resultant loss of the sulcal depth. She reported a 1-year history of variable right-sided facial swelling for which she had undergone extraoral incision and drainage, resulting in localized paresthesia and nonhealing of the incision site. Following exclusion tests, a treatment of twice-daily extraoral application of tacrolimus 0.1% ointment was commenced. Upon review, the lesion had reduced in size, with minimal discharge. Further improvement over 12 months of tacrolimus use resulted in a satisfactory cosmetic result as well as resolution of the intraoral features and reestablishment of the full sulcal depth. This case illustrates the successful use of topical tacrolimus to treat a cutaneous manifestation of Crohn's disease.

What is left when anti-tumour necrosis factor therapy in inflammatory bowel diseases fails?

The inflammatory bowel diseases (IBDs) are chronic incurable conditions that primarily present in young patients. Being incurable, the IBDs may be part of the patient’s life for many years and these conditions require therapies that will be effective over the long-term. Surgery in Crohn’s disease does not cure the disease with endoscopic recurrent in up to 70% of patients 1 year post resection. This means that, the patient will require many years of medications and the goal of the treating physician is to induce and maintain long-term remission without side effects. The development of the anti-tumour necrosis factor alpha (TNFα) agents has been a magnificent clinical advance in IBD, but they are not always effective, with loss of response overtime and, at times, discontinuation is required secondary to side effects. So what options are available if of the anti-TNFα agents can no longer be used? This review aims to provide other options for the physician, to remind them of the older established medications like azathioprine/6-mercaptopurine and methotrexate, the less established medications like mycophenolate mofetil and tacrolimus as well as newer therapeutic options like the anti-integins, which block the trafficking of leukocytes into the intestinal mucosa. The location of the intestinal inflammation must also be considered, as topical therapeutic agents may also be worthwhile to consider in the long-term management of the more challenging IBD patient. The more options that are available the more likely the patient will be able to have tailored therapy to treat their disease and a better long-term outcome.

Diagnosis and treatment of perianal Crohn disease: NASPGHAN clinical report and consensus statement

Inflammatory bowel disease is a chronic inflammatory disorder of the gastrointestinal tract that includes both Crohn disease (CD) and ulcerative colitis. Abdominal pain, rectal bleeding, diarrhea, and weight loss characterize both CD and ulcerative colitis. The incidence of IBD in the United States is 70 to 150 cases per 100,000 individuals and, as with other autoimmune diseases, is on the rise. CD can affect any part of the gastrointestinal tract from the mouth to the anus and frequently will include perianal disease. The first description connecting regional enteritis with perianal disease was by Bissell et al in 1934, and since that time perianal disease has become a recognized entity and an important consideration in the diagnosis and treatment of CD. Perianal Crohn disease (PCD) is defined as inflammation at or near the anus, including tags, fissures, fistulae, abscesses, or stenosis. The symptoms of PCD include pain, itching, bleeding, purulent discharge, and incontinence of stool. In this report, we review and discuss the etiology, diagnosis, evaluation, and treatment of PCD.

Topical tacrolimus 0.1% ointment for treatment of cutaneous Crohn's Disease

Background

Cutaneous Crohn’s Disease is a notoriously difficult condition to treat and causes significant morbidity, impacting heavily on quality of life. This is the first study in adults examining the effect of topical tacrolimus on the different cutaneous manifestations of Crohn’s Disease.

Methods

This open label observational study of 20 patients with heterogeneous forms of cutaneous Crohn’s disease used topical tacrolimus 0.1% ointment once daily to affected areas for 12 weeks with a maximal total dose of 90g. Therapy was stopped at 12 weeks to assess whether the condition relapsed. Thereafter relapsing patients optionally continued an open label extension of topical tacrolimus therapy and were observed for a total of 12 months.

Results

Of seventeen patients completing the twelve-week study, fifteen improved using a specifically designed physicians’ global severity scale. One patient cleared, four showed a pronounced improvement (51-75%) and ten demonstrated a mild (1-25%) or moderate improvement (25-50%) in twelve weeks. Over twelve months eleven patients remained in the study, nine of which improved, one cleared and one showed no change. Perineal disease responded better with two out of twelve clearing, four showing pronounced benefit and four mild to moderate improvement. Long-term application of 0.1% tacrolimus applied to broken skin and mucosa was safe and serum levels of tacrolimus were undetectable in all subjects throughout the study.

Conclusion

0.1% tacrolimus ointment was safe and effective in treating cutaneous manifestations of Crohn’s disease, particularly perineal disease and pyoderma gangrenosum, yet it seldom cleared the condition.

Clinical trial registration

ClinicalTrials.gov Protocol Registration System ID: 33000332

Managing Perianal Crohn’s Disease

Perianal Crohn’s Disease (CD) is a significant cause of morbidity in CD patients. Accurate identification of perianal involvement requires advanced imaging techniques in addition to physical exam. Treatment of the disease is aimed at improving both the perianal and intestinal manifestations. Proper treatment depends upon the severity of the disease and combines current medical and surgical therapies to maximize response. The ability to improve perianal disease has grown significantly since the introduction of anti-TNF agents which are now a mainstay of treatment along with antibiotics and immunomodulators. New experimental therapies are limited by lack of research to support their use.

Update on anal fistulae: surgical perspectives for the gastroenterologist

Anal fistulae are common and debilitating; they are characterized by severe pain and discharge. They arise following infection near the anal canal, or as a primary event from an abscess in the abdomen, fistulating into the vagina or perianal skin. The term 'cryptoglandular' is given to abscesses arising from the anal glands.For many years, the treatment of choice was to lay open the fistula; however, this risks causing incontinence with potentially devastating consequences. Alternative surgical treatments include setons, fibrin glue, collagen plugs and flaps to cover the internal fistula opening. These have achieved varying degrees of success, as will be discussed. The present review also discusses anal fistulae in light of much recently published literature. Currently, anal fistulae remain challenging and require specialist expertise; however, new treatment options are on the horizon.

Systematic review: the role of tacrolimus in the management of Crohn's disease

BACKGROUND  Several published studies have evaluated the efficacy of tacrolimus in the management of Crohn's disease with variable conclusions. AIM  To review systematically the evidence examining the efficacy and safety of tacrolimus in treating Crohn's disease. METHODS  The Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (PUBMED) and EMBASE (1984 to January 2011) were searched. Also, references from selected articles were examined. Case series (five or more patients), cohort and randomised controlled trials were eligible for inclusion, incorporating oral, intravenous or topical tacrolimus therapy. The primary outcome was induction of remission of active Crohn's disease. RESULTS  Eleven studies met the inclusion criteria which included 163 patients, of which 127 received tacrolimus therapy. In patients with luminal Crohn's disease, the crude pooled remission rate for tacrolimus was 44.3% (range, 7-69%) and the crude pooled response rate was 37.1% (range, 14-57%). For patients with perianal disease using systemic tacrolimus, crude pooled remission rate was 28.6% (range, 0-64%) and crude pooled response rate was 38.8% (range, 0-57%). Combining data from two studies using topical tacrolimus, 35.7% of patients achieved remission and 28.6% partial response. Nonserious adverse effects are common, particularly tremor, paraesthesia and headache. Reversible nephrotoxity occurred in 16% of patients. CONCLUSIONS  The current evidence; although of a poor quality, appears to support the use of tacrolimus in Crohn's disease. High quality randomised controlled trials are needed.