Review article: The medical treatment of Crohn's perianal fistulas

Efficacy and Safety of Filgotinib for the Treatment of Perianal Fistulising Crohn's Disease [DIVERGENCE 2]: A Phase 2, Randomised, Placebo-controlled Trial

BACKGROUND AND AIMS

There is an unmet need in the treatment of perianal fistulising Crohn's disease [PFCD]. This study evaluated the efficacy and safety of the Janus kinase 1 preferential inhibitor, filgotinib, for the treatment of PFCD.

METHODS

This phase 2, double-blind, multicentre trial enrolled adults with PFCD and prior treatment failure. Participants were randomised [2:2:1] to receive filgotinib 200 mg, filgotinib 100 mg, or placebo, once daily orally for up to 24 weeks. The primary endpoint was combined fistula response (reduction from baseline of at least one draining external opening determined by physical assessment, and no fluid collections >1 cm on pelvic magnetic resonance imaging [MRI]) at Week 24.

RESULTS

Between April 2017 and July 2020, 106 individuals were screened and 57 were randomised. Discontinuations were lowest in the filgotinib 200 mg group (3/17 [17.6%] versus 13/25 [52.0%] for filgotinib 100 mg and 9/15 [60.0%] for placebo). The proportion of participants who achieved a combined fistula response at Week 24 was 47.1% (8/17; 90% confidence interval [CI] 26.0, 68.9%) in the filgotinib 200 mg group, 29.2% [7/24; 90% CI 14.6, 47.9%] in the filgotinib 100 mg group, and 25.0% [3/12; 90% CI 7.2, 52.7%] in the placebo group. Serious adverse events occurred more frequently with filgotinib 200 mg (5/17 [29.4%]) than with placebo (1/15 [6.7%]). There were no treatment-related serious adverse events or deaths.

CONCLUSIONS

Filgotinib 200 mg was associated with numerical reductions in the number of draining perianal fistulas based on combined clinical and MRI findings compared with placebo, and was generally well tolerated [NCT03077412].

Where Are We and Where to Next?-The Future of Perianal Crohn's Disease Management

Perianal fistulizing Crohn's Disease (pCD) affects about 25% of patients with Crohn's Disease (CD). It remains a difficult entity to manage with a therapeutic ceiling of treatment success despite improving medical and surgical management. The refractory nature of the disease calls for an imminent need to better understand its immunopathogenesis and classification to better streamline our treatment options. In this article, we overview the current state of pCD management and discuss where the future of its management may lie.

Stem cells in treatment of crohn's disease: Recent advances and future directions

BACKGROUND AND AIM

Crohn's disease (CD) is an inflammatory bowel disease that can affect any part of the intestine. There is currently no recognized cure for CD because its cause is unknown. One of the modern approaches that have been suggested for the treatment of CD and other inflammatory-based disorders is cell therapy.

METHODS

Search terms were stem cell therapy, CD, adipose-derived stem cells, mesenchymal stem cells, and fistula. Of 302 related studies, we removed duplicate and irrelevant papers and identified the ones with proper information related to our scope of the research by reviewing all the abstracts and categorizing each study into the proper section.

RESULTS AND CONCLUSION

Nowadays, stem cell therapy is widely implied in treating CD. Although mesenchymal and adipose-derived tissue stem cells proved to be safe in treating Crohn's-associated fistula, there are still debates on an optimal protocol to use. Additionally, there is still a lack of evidence on the efficacy of stem cell therapy for intestinal involvement of CD. Future investigations should focus on preparing a standard protocol as well as luminal stem cell therapy in patients.

Difficult-to-treat inflammatory bowel disease: results from an international consensus meeting

Many patients with inflammatory bowel disease (IBD) have persistent symptoms and disease activity despite the best available medical or surgical treatments. These patients are commonly referred to as having difficult-to-treat IBD and need additional therapeutic strategies. However, the absence of standard definitions has impeded clinical research efforts and comparisons of data. Under the guidance of the endpoints cluster of the International Organization for the Study of Inflammatory Bowel Disease, we held a consensus meeting to propose a common operative definition for difficult-to-treat IBD. 16 participants from 12 countries voted on 20 statements covering various elements of difficult-to-treat IBD, such as failure of medical and surgical treatments, disease phenotypes, and specific complaints from patients. "Agreement" was defined as at least 75% consensus. The group agreed that difficult-to-treat IBD is defined by the failure of biologics and advanced small molecules with at least two different mechanisms of action, or postoperative recurrence of Crohn's disease after two surgical resections in adults, or one in children. In addition, chronic antibiotic-refractory pouchitis, complex perianal disease, and comorbid psychosocial complications that impair disease management also qualified as difficult-to-treat IBD. Adoption of these criteria could serve to standardise reporting, guide enrolment in clinical trials, and help identify candidates for enhanced treatment strategies.

Surgical management of complex perianal fistula revisited in a systematic review: a critical view of available scientific evidence

BACKGROUND

Treating complex perianal fistulas in Crohn's disease patients remains a challenge. Classical surgical treatments for Crohn's disease fistulas have been extrapolated from cryptoglandular fistulas treatment, which have different etiology, and this might interfere with its effectiveness, in addition, they increase fecal incontinence risk. Recently, new surgical techniques with support from biological approaches, like stem cells, have been developed to preserve the function of the sphincter. We have performed a systematic literature review to compare the results of these different techniques in the treatment of Crohn's or Cryptoglandular fistula.

METHODS

PubMed, EMBASE, Database of Abstracts of Reviews of Effectiveness, Cochrane Central Register of Controlled Trials were searched systematically for relevant articles. We included randomized controlled trials and observational studies that referred to humans, were written in English, included adults 18+ years old, and were published during the 10-year period from 2/01/2010 to 2/29/2020. Evidence level was assigned as designated by the Scottish Intercollegiate Guidelines Network.

RESULTS

Of the 577 citations screened, a total of 79 were ultimately included in our review. In Crohn's disease patients, classical techniques such as primarily seton, Ligation of Intersphincteric Fistula Tracks, or lay open, healing rates were approximately 50-60%, while in cryptoglandular fistula were around, 70-80% for setons or flaps. In Crohn's disease patients, new surgical techniques using derivatives of adipose tissue reported healing rates exceeding 70%, stem cells-treated patients achieved higher combined remission versus controls (56.3% vs 38.6%, p = 0.010), mesenchymal cells reported a healing rate of 80% at week 12. In patients with cryptoglandular fistulas, a healing rate of 70% using derivatives of adipose tissue or platelets was achieved, and a healing rate of 80% was achieved using laser technology. Fecal incontinence was improved after the use of autologous platelet growth factors and Nitinol Clips.

CONCLUSION

New surgical techniques showed better healing rates in Crohn's disease patients than classical techniques, which have better results in cryptoglandular fistula than in Crohn's disease. Healing rates for complex cryptoglandular fistulas were similar between the classic and new techniques, being the new techniques less invasive; the incontinence rate improved with the current techniques.

Increasing experience with the LIFT procedure in Crohn's disease patients with complex anal fistula

BACKGROUND

Surgical management of anal fistulas in Crohn's disease (CD) is associated with high failure rates, and treatment options are limited due to ongoing proctitis, multiple tracts, and concern for incontinence and non-healing wounds. The aim of this study was to investigate the healing rate of ligation of the inters-sphincteric fistula tract (LIFT) for anal fistulas in Crohn's disease and identify prognostic factors for healing.

METHODS

This prospective analysis compared long-term healing rates of CD patients undergoing LIFT for anal fistulas. Consecutive patients with CD who underwent LIFT procedure at our institution, in the period from March 2012 to September 2019 were included. The main outcome was anal fistula healing rate.

RESULTS

The study cohort of 46 patients (mean age of 34.2 ± 13.0 years, 18 (40%) males). After a mean follow-up time of 33 ± 28 months, fistula healing was seen in 30 (65%) patients. A total of 8 patients were noted to have inter-sphincteric recurrence and 8 patients had trans-sphincteric recurrence. Smoking at the time of surgery was significantly associated with LIFT failure (HR 3.18, 95% CI 1.18-8.61, p = 0.02). Other factors, such as age, sex, race, disease duration and location, type of fistula history of proctitis, preoperatively use of biologics or a seton, and previous repair attempts, did not appear to influence LIFT healing. Although not statistically significant, there was a trend toward increase in failure among patients with active proctitis at the time of surgery (HR 1.97, 95% CI 0.71-5.42, p = 0.19).

CONCLUSION

Our increasing experience with LIFT for anal fistula in CD demonstrates a higher rate of healing (65%) than previously reported (48%). Smoking appears to negatively influence healing of LIFT in CD.

Regenerative medicine for digestive fistulae therapy: Benefits, challenges and promises of stem/stromal cells and emergent perspectives via their extracellular vesicles

Despite current management strategies, digestive fistulae remain extremely debilitating complications associated with significant morbidity and mortality, generating a need to develop innovative therapies in these indications. A number of clinical trials and experimental studies have thus investigated the potential of stem/stromal cells (SCs) or SC-derived extracellular vesicles (EVs) administration for post-surgical and Crohn's-associated fistulae. This review summarizes the physiopathology and current standards-of-care for digestive fistulae, along with relevant evidence from animal and clinical studies regarding SC or EV treatment for post-surgical digestive fistulae. Additionally, existing preclinical models of fistulizing Crohn's disease and results of SC therapy trials in this indication will be presented. The optimal formulation and administration protocol of SC therapy products for gastrointestinal fistula treatment and the challenges for a widespread use of darvadstrocel (Alofisel) in clinical practice will be discussed. Finally, the potential advantages of EV therapy and the obstacles towards their clinical translation will be introduced.

Cx601 (darvadstrocel) for the treatment of perianal fistulizing Crohn's disease

Introduction: Given the well-documented difficulty to treat perianal fistulizing Crohn's disease (pCD), with 40% of patients experiencing recurrence even after reiterative surgery and advanced medical therapy, research in this field has focused on the role of mesenchymal stem cells (MSC). Areas covered: The aim of this article is to furnish an overview of the pathogenetic mechanisms, clinical applications and evidences for the use of MSC for pCD with particular focus on adipose-derived allogenic MSC including darvadstrocel. Expert Opinion: The effect of MSC on fistula healing is probably mediated by their anti-inflammatory properties more than by their ability to engraft and trans-differentiate in the healthy tissue. A holistic treatment of pCD, addressing different pathophysiological factors, may represent the key for an improvement in the healing rate. In this setting, MSC might play a role as 'augmentation' therapy in combination with more conventional treatments. Whether MSC have benefit in non-complex fistula in biological naïve patients, in complex fistula with many tracts and/or in rectovaginal fistulas, are unexplored fields that need further investigation. A central registry of pCD patients undergoing treatment with MSC should be created in order to elucidate the efficacy, safety and costs of stem cells treatment on long term follow up.

Surgery in the age of biologics

Since the introduction of the first anti-tumor necrosis factor antibodies in the late 1990s, biologic therapy has revolutionized the medical treatment of patients with inflammatory bowel disease (IBD). Nevertheless, surgery continues to play a significant role in treating IBD patients. Rates of intestinal resection in patients with Crohn's disease or colectomy in ulcerative colitis are reducing but not substantially over the long term. An increasing variety of biologic medications are now available to treat IBD patients in various clinical situations. Consequently, a number of questions persist about how biologic medications affect the need for surgery and overall course in IBD patients. Given the trend for earlier and more frequent use of biologic medications in IBD patients, a working knowledge of the effects of these medications on surgical decision-making and outcomes is essential for the practicing colorectal surgeon and gastroenterologist. This review seeks to summarize the relevant literature surrounding biologic use and IBD surgery with a focus on the effect of biologics on the frequency, type and complications of surgery in this 'age of biologics'.

Long-term Efficacy and Safety of Stem Cell Therapy (Cx601) for Complex Perianal Fistulas in Patients With Crohn's Disease

BACKGROUND & AIMS

Therapies for perianal fistulas in patients with Crohn's disease are often ineffective in producing long-term healing. We performed a randomized placebo-controlled trial to determine the long-term efficacy and safety of a single local administration of allogeneic expanded adipose-derived stem cells (Cx601) in patients with Crohn's disease and perianal fistulas.

METHODS

We performed a double-blind study at 49 hospitals in Europe and Israel, comprising 212 patients with Crohn's disease and treatment-refractory, draining, complex perianal fistulas. Patients were randomly assigned (1:1) to groups given a single local injection of 120 million Cx601 cells or placebo (control), in addition to the standard of care. Efficacy endpoints evaluated in the modified intention-to-treat population (randomly assigned, treated, and with 1 or more post-baseline efficacy assessment) at week 52 included combined remission (closure of all treated external openings draining at baseline with absence of collections >2 cm, confirmed by magnetic resonance imaging) and clinical remission (absence of draining fistulas).

RESULTS

The study's primary endpoint, at week 24, was previously reported (combined remission in 51.5% of patients given Cx601 vs 35.6% of controls, for a difference of 15.8 percentage points; 97.5% confidence interval [CI] 0.5-31.2; P = .021). At week 52, a significantly greater proportion of patients given Cx601 achieved combined remission (56.3%) vs controls (38.6%) (a difference of 17.7 percentage points; 95% CI 4.2-31.2; P = .010), and clinical remission (59.2% vs 41.6% of controls, for a difference of 17.6 percentage points; 95% CI 4.1-31.1; P = .013). Safety was maintained throughout week 52; adverse events occurred in 76.7% of patients in the Cx601 group and 72.5% of patients in the control group.

CONCLUSION

In a phase 3 trial of patients with Crohn's disease and treatment-refractory complex perianal fistulas, we found Cx601 to be safe and effective in closing external openings, compared with placebo, after 1 year. ClinicalTrials.gov no: NCT01541579.

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.

Increasing experience of ligation of the intersphincteric fistula tract for patients with Crohn's disease: what have we learned?

AIM

Ligation of the intersphincteric fistula tract (LIFT) has been proposed as a treatment of trans-sphincteric fistula in perianal Crohn's disease (CD). The aim of this study was to look at our experience of the LIFT procedure in CD patients on long-term follow-up. Specifically, we aimed to determine the fistula healing rate after the LIFT procedure after more than 12 months follow-up and to identify any prognostic factors.

METHOD

Retrospective study of patients with trans-sphincteric Crohn's fistula tracts treated with the LIFT procedure between January 2011 and October 2015. Complete fistula healing as well as clinical outcomes were analysed.

RESULTS

Data were available for 23 patients. After a median follow-up of 23 months, LIFT site healing was 48%. Patients with healed LIFT had a median follow-up time of 10.5 months, while patients with failed LIFT had a median follow-up time of 31 months (P = 0.04). Median time to failure was 9 months for patients with follow-up > 1 year. Most patients failed within 1 year (9/12; 75%) of the procedure. In multi-site CD, the LIFT procedure was more likely to be successful in those with small bowel disease (P = 0.04) compared with colonic disease (P = 0.02). Other factors such as preoperative use of biological therapies, presence of a seton, previous repair attempts, fistula position, type or number of fistulas, multiple fistula tracts, smoking status and other associated perianal disease did not appear to influence LIFT healing rates.

CONCLUSION

The LIFT procedure offers reasonable long-term success in the treatment of perianal trans-sphincteric fistulas associated with CD. LIFT is more likely to fail in patients with concurrent colonic CD than in patients with small bowel CD.

Magnetic resonance imaging may predict deep remission in patients with perianal fistulizing Crohn's disease

AIM

To evaluate the imaging course of Crohn’s disease (CD) patients with perianal fistulas on long-term maintenance anti-tumor necrosis factor (TNF)-α therapy and identify predictors of deep remission.

METHODS

All patients with perianal CD treated with anti-TNF-α therapy at our tertiary care center were evaluated by magnetic resonance imaging (MRI) and clinical assessment. Two MR examinations were performed: at initiation of anti-TNF-α treatment and then at least 2 years after. Clinical assessment (remission, response and non-response) was based on Present’s criteria. Rectoscopic patterns, MRI Van Assche score, and MRI fistula activity signs (T2 signal and contrast enhancement) were collected for the two MR examinations. Fistula healing was defined as the absence of T2 hyperintensity and contrast enhancement on MRI. Deep remission was defined as the association of both clinical remission, absence of anal canal ulcers and healing on MRI. Characteristics and imaging patterns of patients with and without deep remission were compared by univariate and multivariate analyses.

RESULTS

Forty-nine consecutive patients (31 females and 18 males) were included. They ranged in age from 14-70 years (mean, 33 years). MRI and clinical assessment were performed after a mean period of exposure to anti-TNF-α therapy of 40 ± 3.7 mo. Clinical remission, response and non-response were observed in 53.1%, 20.4%, and 26.5% of patients, respectively. Deep remission was observed in 32.7% of patients. Among the 26 patients in clinical remission, 10 had persisting inflammation of fistulas on MRI (T2 hyperintensity, n = 7; contrast enhancement, n = 10). Univariate analysis showed that deep remission was associated with the absence of rectal involvement and the absence of switch of anti-TNF-α treatment or surgery requirement. Multivariate analysis demonstrated that only the absence of rectal involvement (OR = 4.6; 95%CI: 1.03-20.5) was associated with deep remission.

CONCLUSION

Deep remission is achieved in approximately one third of patients on maintenance anti-TNF-α therapy. Absence of rectal involvement is predictive of deep remission.

MR Imaging of Perianal Crohn Disease

Pelvic magnetic resonance (MR) imaging is currently the standard for imaging perianal Crohn disease. Perianal fistulas are a leading cause of patient morbidity because closure often requires multimodality treatments over a prolonged period of time. This review summarizes clinically relevant anal sphincter anatomy, imaging methods, classification systems, and treatment objectives. In addition, the MR appearance of healing perianal fistulas and fistula complications is described. Difficult imaging tasks including the assessment of rectovaginal fistulas and ileoanal anastomoses are highlighted, along with illustrative cases. Emerging innovative treatments for perianal Crohn disease are now available and have the promise to better control sepsis and maintain fecal continence. Different treatment modalities are selected based on fistula anatomy, patient factors, and management goals (closure versus sepsis control). Radiologists can help maximize patient care by being familiar with MR imaging features of perianal Crohn disease and knowledgeable about what features may influence therapy decisions. ^© RSNA, 2017 Online supplemental material is available for this article.

MRI characteristics of proctitis in Crohn's disease on perianal MRI

Purpose

Multiple features have been described for assessing inflammation in Crohn’s disease (CD) in MR enterography, but have not been validated in perianal magnetic resonance imaging (MRI). Retrospectively, we studied which MRI features are valuable in assessing proctitis.

Materials and methods

CD patients (≥18 years) who underwent colonoscopy (reference standard) and perianal fistula MRI within 8 weeks were included. Seventeen MRI features were blindly scored by three observers and correlated to endoscopy (regression analysis). Reproducibility (multirater kappa, intraclass correlation coefficient) was determined for all three observer pairs. MRI features were considered relevant when significantly correlated to endoscopy for ≥2 observers, and reproducibility was ≥0.40 for ≥2 observer pairs.

Results

Perianal MRI of 58 CD patients were included. Wall thickness, rectal mural fat, creeping fat, and size of mesorectal lymph nodes showed a significant correlation with endoscopy for ≥2 observers (p = 0.000–0.023, p = 0.011–0.172, p = 0.007–0.011 and p = 0.000–0.005, respectively) with a kappa/intraclass correlation coefficient of ≥0.60 for ≥2 observer pairs. Perimural T2 signal and perimural enhancement significantly correlated to endoscopy (all p values ≤0.05) for all three observers and the reproducibility was ≥0.40 for ≥2 observer pairs. Mural T2 signal and degree and pattern of T1 enhancement showed significant correlation to endoscopy for two observers, but with poor to moderate reproducibility.

Conclusion

Wall thickness, mural fat, and mesorectal features (perimural T2 signal, perimural enhancement, creeping fat, and size of mesorectal lymph nodes) had significant correlation to endoscopy and were reproducible in diagnosing proctitis. Some established luminal features in MRE were considered not useful.

Expanded allogeneic adipose-derived mesenchymal stem cells (Cx601) for complex perianal fistulas in Crohn's disease: a phase 3 randomised, double-blind controlled trial

BACKGROUND

Complex perianal fistulas in Crohn's disease are challenging to treat. Allogeneic, expanded, adipose-derived stem cells (Cx601) are a promising new therapeutic approach. We aimed to assess the safety and efficacy of Cx601 for treatment-refractory complex perianal fistulas in patients with Crohn's disease.

METHODS

We did this randomised, double-blind, parallel-group, placebo-controlled study at 49 hospitals in seven European countries and Israel from July 6, 2012, to July 27, 2015. Adult patients (≥18 years) with Crohn's disease and treatment-refractory, draining complex perianal fistulas were randomly assigned (1:1) using a pre-established randomisation list to a single intralesional injection of 120 million Cx601 cells or 24 mL saline solution (placebo), with stratification according to concomitant baseline treatment. Treatment was administered by an unmasked surgeon, with a masked gastroenterologist and radiologist assessing the therapeutic effect. The primary endpoint was combined remission at week 24 (ie, clinical assessment of closure of all treated external openings that were draining at baseline, and absence of collections >2 cm of the treated perianal fistulas confirmed by masked central MRI). Efficacy was assessed in the intention-to-treat (ITT) and modified ITT populations; safety was assessed in the safety population. This study is registered with ClinicalTrials.gov, number NCT01541579.

FINDINGS

212 patients were randomly assigned: 107 to Cx601 and 105 to placebo. A significantly greater proportion of patients treated with Cx601 versus placebo achieved combined remission in the ITT (53 of 107 [50%] vs 36 of 105 [34%]; difference 15·2%, 97·5% CI 0·2-30·3; p=0·024) and modified ITT populations (53 of 103 [51%] vs 36 of 101 [36%]; 15·8%, 0·5-31·2; p=0·021). 18 (17%) of 103 patients in the Cx601 group versus 30 (29%) of 103 in the placebo group experienced treatment-related adverse events, the most common of which were anal abscess (six in the Cx601 group vs nine in the placebo group) and proctalgia (five vs nine).

INTERPRETATION

Cx601 is an effective and safe treatment for complex perianal fistulas in patients with Crohn's disease who did not respond to conventional or biological treatments, or both.

FUNDING

TiGenix.

Emerging trends and risk factors for perianal surgery in Crohn's disease: a 20-year national population-based cohort study

BACKGROUND

Little is known about the rates of perianal surgery (PAS) in Crohn's disease (CD). Our aim was to determine trends in PAS, the timing of surgery relative to the diagnosis of CD and to identify subgroups at risk of PAS.

MATERIALS AND METHODS

We identified 9391 incident cases of CD between 1989 and 2009. We defined three eras: era 1 (1989-1995), era 2 (1996-2002) and era 3 (2003-2009), and determined trends in procedure type and the time to first PAS relative to the date of diagnosis. We used Kaplan-Meier analysis to calculate the rate of first PAS and performed Cox regression to determine subgroups at risk of PAS.

RESULTS

Among the 9391 incident cases of CD, 405 (4.3%) underwent PAS. The overall rate of PAS was 5.5% [95% confidence interval (CI): 4.9-6.2%] 10 years after diagnosis. 34% (n=137) of all patients undergoing PAS had surgery in the 5 years before CD diagnosis. Abscess drainage increased from 34 to 58%, whereas proctectomy decreased from 16 to 6% between eras 1 and 3, respectively. Men [hazard rate (HR) 1.51, 95% CI: 1.24-1.84], those aged 17-40 years (HR 1.69, 95% CI: 1.09-2.02 vs. those aged >40 years) and those with a history of previous intestinal resection (HR 28.5, 95% CI: 22.2-36.5) were more likely to have PAS.

CONCLUSION

Around one-third of patients have a PAS in the 5 years preceding their diagnosis of CD. Surgical practice has changed over 20 years, with a decrease in proctectomy and a concurrent increase in abscess drainage that is likely to reflect improvements in therapeutic practice.

Results of the Fifth Scientific Workshop of the ECCO [II]: Clinical Aspects of Perianal Fistulising Crohn's Disease-the Unmet Needs

BACKGROUND AND AIMS

Perianal fistulas affect up to one-third of Crohn's patients during the course of their disease. Despite the considerable disease burden, current treatment options remain unsatisfactory. The Fifth Scientific Workshop [SWS5] of the European Crohn's and Colitis Organisation [ECCO] focused on the pathophysiology and clinical impact of fistulas in the disease course of patients with Crohn's disease [CD].

METHODS

The ECCO SWS5 Working Group on clinical aspects of perianal fistulising Crohn's disease [pCD] consisted of 13 participants, gastroenterologists, colorectal surgeons, and a histopathologist, with expertise in the field of inflammatory bowel diseases. A systematic review of literature was performed.

RESULTS

Four main areas of interest were identified: natural history of pCD, morphological description of fistula tracts, outcome measures [including clinical and patient-reported outcome measures, as well as magnetic resonance imaging] and randomised controlled trials on pCD.

CONCLUSIONS

The treatment of perianal fistulising Crohn's disease remains a multidisciplinary challenge. To optimise management, a reliable classification and proper trial endpoints are needed. This could lead to standardised diagnosis, treatment, and follow-up of Crohn's perianal fistulas and the execution of well-designed trials that provide clear answers. The prevalence and the natural history of pCD need further evaluation.

A prospective evaluation of the ligation of the intersphincteric tract procedure for complex anal fistula in patients with Crohn's disease

OBJECTIVE

To evaluate 2- and 12-month outcomes after ligation of the intersphincteric fistula tract (LIFT) in Crohn's disease (CD).

BACKGROUND

Surgical approaches to perianal fistulas in CD are frequently ineffective and hampered by concerns over adequate wound healing and sphincter injury. The efficacy of LIFT in CD patients is unknown.

METHODS

Consecutive cases of CD patients with transsphincteric fistulas were prospectively analyzed. Fistula healing and 2 validated quality-of-life indices were assessed.

RESULTS

Fifteen CD patients (9 women; mean age = 34.8 years) were identified. Location of the fistula was lateral (n = 10; 67%) or midline (n = 5; 33%). LIFT site healing was seen in 9 patients (60%) at 2-month follow-up. No patient developed fecal incontinence. LIFT site healing was seen in 8 of the 12 patients (67%) with complete 12-month follow-up. Significant factors for long-term LIFT site healing were lateral versus midline location (P = 0.02) and longer mean fistula length (P = 0.02). Patients who had successful operations significantly improved both their mean Wexner Perianal Crohn's Disease Activity Index and McMaster Perianal Crohn's Disease Activity Index quality-of-life scores at 2-month follow-up (14.0-3.8, P = 0.001, and 10.4-1.8, P = 0.0001, respectively).

CONCLUSIONS

CD-associated anal fistulas may be treated with LIFT. This surgical procedure is a safe, outpatient procedure that minimizes both perianal wound creation and sphincter injury.

Crohn's disease: Fistulising disease--a problem shared is a problem halved?

An international consensus on the classification, diagnosis and multidisciplinary treatment of perianal fistulising Crohn's disease has recently been published. The statement is an important starting point to address the many problems we still have with the clinical classification and treatment of fistulising Crohn's disease.

Systematic review: the combined surgical and medical treatment of fistulising perianal Crohn's disease

BACKGROUND

The management of perianal Crohn's fistulas represents a significant challenge. A combination of medical and surgical therapy, guided by radiology, is often required.

AIM

To review systematically the literature to assess fistula healing rates with medical treatment (anti-TNF-α therapies ± immunomodulators) or surgical treatment alone, compared with combined medical and surgical treatment in fistulising perianal Crohn's disease (CD).

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used. Two independent reviewers searched the literature.

RESULTS

Twenty-four articles were included. The total population was 1139 patients; 460 (40%) received single treatment with either medical or surgical therapy, and 679 (60%) received combined medical and surgical therapy. Eight studies compared single and combination therapy, with a total population of 797 patients (single therapy: n = 448, combination therapy: n = 349). In the single therapy group, 191/448 were in complete remission (43%). This was lower than the healing rate of the combination therapy group 180/349 (52%). No response to therapy was noted in 34% (153/448) of the single therapy group compared with 23% (80/349) of the combination group.

CONCLUSIONS

Combined surgical and medical (anti-TNF-α ± immunomodulators) therapy may have additional beneficial effects on perianal fistula healing in patients with Crohn's disease, compared with surgery or medical therapy alone. A well-designed Crohn's perianal fistula clinical trial is required in a multidisciplinary medical and surgical setting, with clearly defined end points of clinical (and likely patient reported outcomes) and radiological healing.

AST-120 (spherical carbon adsorbent) in the treatment of perianal fistulae in mild-to-moderate Crohn's disease: FHAST-1, a phase 3, multicenter, placebo-controlled study

BACKGROUND

AST-120 (spherical carbon adsorbent) was previously reported to be effective for perianal fistula healing in Japanese patients with mild-to-moderate Crohn's disease.

METHODS

To evaluate the efficacy and safety of AST-120 in a Western population, a phase 3, multicenter, randomized, double-blind, placebo-controlled, study (FHAST-1) was conducted in adult patients with at least 1 draining perianal fistula and a Crohn's disease activity index <400. Patients received either AST-120 or matching placebo at a dose of 2 g 3 times daily for 8 weeks. The primary endpoint was the proportion of patients with treatment success, defined as a 50% reduction in the number of draining fistulae, at both weeks 4 and 8. A multivariate model was generated to assess covariates for treatment success among baseline variables.

RESULTS

Two hundred forty-nine patients were randomized (AST-120; n = 122; placebo, n = 127). The proportions of patients achieving the primary endpoint were no different between treatment groups (13.9% versus 16.5%, P = 0.6). No differences in fistula response were noted at week 4 (23.0% versus 25.2%, P = 0.77) or week 8 (27.0 versus 34.6%, P = 0.22). Serum C-reactive protein concentrations >0.6 mg/dL and Crohn's disease activity index scores >151 at baseline were associated with a reduced likelihood of treatment success (odds ratio, 0.40; confidence interval, 0.19-0.87; P = 0.02; and odds ratio, 0.45; confidence interval, 0.21-0.97; P = 0.04, respectively).

CONCLUSIONS

In this largest placebo-controlled trial to date to evaluate the impact of a therapeutic agent on perianal fistulae in Crohn's disease, the efficacy of AST-120 could not be confirmed. An inverse relationship was observed between both inflammatory and clinical disease activity and fistula response.

The impact of thiopurines on surgical outcomes in inflammatory bowel disease: do they make a difference?

Ulcerative colitis and Crohn's disease together are known as inflammatory bowel disease (IBD). Surgery is considered for more severe disease and is a dreaded consequence for patients. Thiopurines have proven efficacy in the induction and maintenance of remission of IBD, but the long-term need for surgery remains uncertain with conflicting results from the available studies. The timing and duration of thiopurines also appears to play a pivotal role in the management of these conditions and may also affect the need for surgery. Data from Denmark, Canada, Hungary and the UK appear to suggest a reduction in surgery rates prior to the introduction of anti-tumor necrosis factor (TNF) therapy. The authors aim to review the more recent literature evaluating the surgery rates in IBD and changes in disease trends over time. We ask whether increasing thiopurine prescribing has had an effect on the surgery rates in the era of biologic therapy and whether more aggressive treatment approaches have altered the natural history of IBD.

Imaging techniques and combined medical and surgical treatment of perianal Crohn's disease

Crohn's disease is a chronic inflammatory disease which may involve any segment of the gastrointestinal tract, most frequently the terminal ileum, the large intestine, and the perianal region. The symptoms of perianal Crohn's disease include skin disorders, hemorrhoids, anal ulcers, anorectal stenosis, perianal abscesses and fistulas, rectovaginal fistulas and carcinoma of the perianal region. The perianal manifestations of Crohn's disease cause great discomfort to the patient and are among the most difficult aspects to treat. Management of perianal disease requires a combination of different imaging modalities and a close cooperation between gastroenterologists and dedicated surgeons.

Endoscopic ultrasound for perianal Crohn's disease: disease and fistula characteristics, and impact on therapy

BACKGROUND AND AIM

Appropriate treatment of perianal fistulas in Crohn's disease (CD) involves accurate anatomic evaluation. EUS is an accepted imaging method for this purpose. The aim of the current study was to evaluate the clinical and endosonographic characteristics of perianal fistula in CD and to assess its impact on therapy.

METHODS

All CD patients referred to the Sheba medical center from June 2004 to August 2008 for EUS examination of perianal fistulas were included. Perianal fistulas were diagnosed based on a clinical examination revealing at least one perianal cutaneous orifice. Demographic, clinical and therapeutic data was obtained. EUS was performed using an ultrasound scanner producing a 360° cross sectional image of the anal sphincters.

RESULTS

Fifty six patients were included in the study. Four patients were excluded from the final analysis: 3 because no fistula could be detected by EUS, and one due to inability to tolerate the examination. The mean CD duration was 10±9.16 years (range 1-37). Mean perianal disease duration was 5.3±6.5 (range 1-29) years. 27 patients had perianal involvement at presentation. Among the fistulas diagnosed, 13 were simple (25%) and 39 were (75%) complex. No correlation was found between CD duration or location, patients' age and gender or fistula location with fistula type or complexity. EUS results influenced patient management in 86% of the patients.

CONCLUSIONS

CD-associated perianal fistulas are mainly complex. EUS is a well tolerated and informative imaging modality, with significant impact on treatment.

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.

Fistulizing perianal Crohn's disease: contrast-enhanced magnetic resonance imaging assessment at 1 year on maintenance anti-TNF-alpha therapy

BACKGROUND

The aim of the study was to assess perianal fistulas by magnetic resonance imaging (MRI) in patients with severe fistulizing Crohn's disease (CD) using maintenance antitumor necrosis factor alpha (TNF-α) therapy and to correlate MRI changes with clinical outcome.

METHODS

Perineal MRI before and after a 1-year scheduled anti-TNF-α maintenance therapy was performed in 20 patients (14 females; mean age = 33.7). The Van Assche score (i.e., number of fistulas, localization, and extension, importance of T2 hyperintensity, presence of abscess) was calculated. Fistula track contrast enhancement was also used. Clinical outcome was defined as no response, response, or remission.

RESULTS

Response and remission were observed in respectively 40% and 35% of cases. The Van Assche score varied from 13.8 (7-20) to 6.13 (0-12) in patients with a response or remission (P < 0.05). The T2 hyperintensity follow-up value decreased in patients in response or remission (P < 0.01). T2 hyperintensity disappeared or decreased in 14 out of 15 patients in clinical response or remission as compared to one among the five nonresponding patients (P < 0.01). The decrease in Van Assche score and hyperintensity value was not significantly different in patients in remission compared to those with response. Only one patient in clinical remission had a persisting contrast enhancement on MRI, whereas contrast enhancement persisted in all other patients not in remission (P = 0.002).

CONCLUSIONS

The clinical benefit of maintenance anti-TNF-α therapy in perianal CD is associated with a significant improvement of the Van Assche score, particularly T2 hyperintensity. The disappearance of contrast enhancement was the only semiological MR feature associated with remission.

CARD15 mutations and perianal fistulating Crohn's disease: correlation and predictive value of antibiotic response

BACKGROUND

CARD15 mutations alter bowel immunity and increase susceptibility to Crohn's disease (CD). However, the relation between these mutations and Crohn's perianal fistulas has not been fully clarified.

AIMS

To assess whether CARD15 mutations are associated with risk of developing Crohn's perianal fistulas and whether these mutations are predictors of the response of perianal fistulas to antibiotics.

METHODS

CARD15 mutations were investigated in 203 consecutive CD patients. Presence/absence of history of perianal fistula was recorded. Patients with history of perianal fistula were divided into two groups (with/without CARD15 mutations), and response to antibiotics was evaluated in both groups.

RESULTS

Of the 203 patients, 60 (29.6%) showed at least one CARD15 mutation and 55 (27.1%) had history of perianal fistula. History of perianal fistula was identified in 13 (21.7%) patients with mutations and in 42 (29.4%) patients without mutations (P = 0.260). Mean age at diagnosis of first perianal fistula was similar in patients with/without CARD15 mutations (28.7 ± 9.8 versus 29.7 ± 10.1 years, P = 0.758). Average time between disease onset and diagnosis of first perianal fistula was also similar in the two groups (4.6 ± 5.1 versus 5.0 ± 5.9 years, P = 0.816). Response of perianal fistulas to antibiotics (metronidazole alone or combined with ciprofloxacin) was significantly higher in patients without CARD15 mutations (7.7% versus 40.5%, P = 0.041).

CONCLUSIONS

In CD, CARD15 mutations are not associated with risk of developing perianal fistulas or with time of their outbreak. Nevertheless, patients with perianal fistulas and CARD15 mutations showed worse response to antibiotics.

Predicting factors of fistula healing and clinical remission after infliximab-based combined therapy for perianal fistulizing Crohn's disease

Perianal fistulizing Crohn's disease (PFCD) treatment is based on fistula drainage, antibiotics, immunosuppressant (IS) drugs, and infliximab. Our aim was to study the effectiveness of combination therapy on PFCD and to search for clinical or imaging features associated with the initial complete clinical response and its stability overtime.

PATIENTS AND METHODS

All patients with PFCD treated in our tertiary center between 2000 and 2005 by infliximab in combination with seton placement and/or IS and evaluated by MRI before treatment were included in the study. Basal clinical and MRI characteristics were recorded. Response to treatment was evaluated after the infliximab induction regiment and at the end of the follow-up.

RESULTS

Twenty-six patients were included and followed-up for an average 4.9 years. A complex fistula was present in 69% (18/26 patients) of cases and eight (8/26 patients) had an ano-vaginal fistula. After infliximab induction therapy, 13 patients (50%) achieved a complete clinical response. The initial clinical response was significantly associated with the absence of both, active intestinal disease (54% vs. 8%, P = 0.03) and active proctitis (77% vs. 23%, P = 0.01). No initial MRI characteristics were linked to the initial response. In multivariate analysis, only the presence of active proctitis was associated with the lack of response (P = 0.047). At the end of the follow-up, 42% of the patients remained in clinical remission. No clinical characteristics were associated to sustained response when among long-standing responders two exhibited a normal post-treatment MRI.

CONCLUSION

An initial complete response of PFCD was observed in half of the patients after combined therapy including infliximab that decreased to 42% later on. Complete healing of fistulas on MRI was possible but unusual. The initial response seemed related to the absence of active intestinal disease, especially in the rectum, when the long-term response could not be predicted by the basal characteristics of patients.

Assessing the activity of perianal Crohn's disease: comparison of clinical indices and computer-assisted anal ultrasound

BACKGROUND

Assessing perianal disease activity is important for the treatment and prognosis of Crohn's disease (CD) patients, but the diagnostic accuracy of the activity indices has not yet been established. The aim of this study was to determine the accuracy and agreement of the Fistula Drainage Assessment (FDA), Perianal Disease Activity Index (PDAI), and computer-assisted anal ultrasound imaging (AUS).

METHODS

Sixty-two consecutive patients with CD and perianal fistulae underwent clinical, FDA, PDAI, and AUS evaluation. Perianal disease was considered active in the presence of visible fistula drainage and/or signs of local inflammation (induration and pain at digital compression) upon clinical examination. The AUS images were analyzed by calculating the mean gray-scale tone of the lesion. The PDAI and gray-scale tone values discriminating active and inactive perianal disease were defined using receiver operating characteristics statistics.

RESULTS

Perianal disease was active in 46 patients. The accuracy of the FDA was 87% (confidence interval [CI]: 76%-94%). A PDAI of >4 and a mean gray-scale tone value of 117 maximized sensitivity and specificity; their diagnostic accuracy was, respectively, 87% (CI: 76%-94%) and 81% (CI: 69%-90%). The agreement of the 3 evaluations was fair to moderate. The addition of AUS to the PDAI or FDA increased their diagnostic accuracy to respectively 95% and 98%.

CONCLUSIONS

The diagnostic accuracy of the FDA, PDAI, and computer-assisted AUS imaging was good in assessing perianal disease activity in patients with CD. The agreement between the techniques was fair to moderate. Overall accuracy can be increased by combining the FDA or PDAI with AUS.

Assessment of antimicrobial microspheres as a prospective novel treatment targeted towards the repair of perianal fistulae

BACKGROUND

None of the proposed materials tested for the management of perianal fistulae has proven to be a definitive treatment.

AIM

To assess a new repair scaffold and drug delivery device conceived to target perianal fistula repair.

METHODS

Poly(D,L-lactide-co-glycolide) porous microspheres containing either antibacterial silver-releasing degradable phosphate glass or metronidazole were prepared using thermally induced phase separation.

RESULTS

Ion- and drug-release profiling of the microspheres revealed continued release of silver ions from microspheres filled with silver-doped phosphate glass and high encapsulation efficiency for metronidazole [78% and 82% for microspheres loaded with 2.5% and 1.3% (w/w), respectively]. Microbicidal activity was confirmed by growth inhibition of bacterial species (Staphylococcus aureus, Escherichia coli and Bacteroides fragilis), which characteristically dominate the colonization of perianal fistula tracts. Microspheres containing >3 mol% silver or metronidazole resulted in strong bacterial inhibition/kill against B. fragilis; the presence of one sphere containing >3 mol% silver had a potent inhibitory effect against all the microbes studied. Microspheres became rapidly integrated with host tissue following subcutaneous implantation into a rodent wound model.

CONCLUSION

The study demonstrates a novel scaffold for guided tissue regeneration providing local release of antimicrobial agents sufficient to counter bacterial colonization and warrants further investigation.

NOD2/CARD15 gene variants are linked to failure of antibiotic treatment in perianal fistulating Crohn's disease

OBJECTIVES

The Crohn's disease (CD) susceptibility gene, nucleotide-binding oligomerizetion domain 2 (NOD2)/caspase recruitment domain 15 (CARD15), is linked to the innate immune response associated with altered epithelial bacterial defense. Its relevance in antibiotic therapy of perianal fistulating CD remains elusive. The aim of the study was to explore systematically the association between NOD2/CARD15 variants and clinical response of perianal fistulas in patients using antibiotic therapy.

METHODS

Fifty-two patients (median age 36 yr) with draining perianal fistulas were treated with ciprofloxacin (N = 49) or metronidazole (N = 3) for a median duration of 7 wk. Complete response was defined as the absence of any draining fistula despite gentle finger compression. Genotyping for NOD2/CARD15 variants and human beta (beta)-defensin 2 (HBD-2) copies was performed by 5' nuclease assays (Applied Biosystems, Foster City, CA). The examiners and laboratory investigators were blinded. The Fisher exact test and Wilcoxon signed rank test were used for statistical analysis.

RESULTS

Ciprofloxacin was discontinued in one patient due to diarrhea after 2 wk. Complete fistula response was observed in 13 of 39 patients with NOD2/CARD15 wild-type (33.3%) compared with none in patients carrying NOD2/CARD15 variants (0%, P= 0.02). The median number of HBD-2 gene copies between responders and partial/nonresponders was similar.

CONCLUSIONS

The study result suggests a substantial contribution of NOD2/CARD15 to the antibiotic treatment outcome of perianal fistulating CD. NOD2/CARD15 variants may predispose to an altered intestinal microflora in perianal fistulas that is less responsive to antibiotic treatment.

The patient with persistent perianal fistulae

The management of patients with persistent perianal fistulae depends on thorough evaluation by clinical history and examination, assessment of intestinal disease and assessment of perianal disease. The main therapeutic options are medical and surgical treatment and their appropriate integration is essential for the optimal management of the patients. Medical treatment includes antibiotics, azathioprine or 6-mercaptopurine, infliximab and tacrolimus or cyclosporine. Surgical treatment includes fistulotomy, placement of setons, endorectal advancement flaps, fecal diversion and proctectomy. Fistula recurrence often occurs, possibly due to early discontinuation of medication or premature removal of setons. Using anorectal endoscopic ultrasound or magnetic resonance imaging to guide therapy, the healing rates of perianal fistula can be increased. In persistent complex perianal fistulae where medical treatment initially fails, examination under anaesthesia and placement of non-cutting setons, when necessary, combined with medical treatment results in higher healing rates.

Antibiotic therapy for Crohn's disease: a review

Increasing evidence suggests that gut bacteria play a pathogenic role in Crohn's disease (CD), providing a rationale for the use of antibiotics in the primary treatment of the disease. While there are data to suggest that antibiotics may be effective in treating active luminal, particularly colonic, and/or perianal CD, evidence for their use in these settings is hampered by the lack of well-designed, adequately powered, placebo-controlled trials. Furthermore, although nitroimidazole antibiotics have been shown to reduce postoperative recurrence following ileocolonic resection, their use is limited by side effects. There is a current need for rigorous multicentre studies looking into the role of antibiotics in treating perianal and luminal CD, as well as a need for the large-scale assessment of novel antibiotics, with low systemic absorption, which may improve patient tolerance.

Infliximab in fistulizing Crohn's disease

The treatment of fistulizing CD has evolved greatly in the last 15 years, largely caused by improvements in medical therapy. Tables 2 and 3 summarize all published controlled and uncontrolled trials of immunomodulator and biologic therapy for the treatment of Crohn's fistulae. The advent of immunomodulators and anti-TNF-alpha agents has transformed the treatment of Crohn's fistulae from almost exclusively surgical to placing a much larger emphasis on medical therapy, either as initial therapy alone, with surgery reserved for refractory cases, or in combination with surgery from the start. For this reason, surgeons and gastroenterologists must work in concert to provide the best care for each patient. Proper fistula management also relies heavily on accurate diagnosis, especially defining the anatomy of the fistula, ascertaining whether abscess formation is present, and determining the location and extent of intestinal inflammation.

Use of endoscopic ultrasound to guide combination medical and surgical therapy for patients with Crohn's perianal fistulas

BACKGROUND

This study was performed to assess if using endoscopic ultrasound (EUS) to assess and guide combination medical and surgical therapy during fistula healing will lead to a high rate of durable fistula closure and a low or absent incidence of perianal abscess formation in patients with Crohn's perianal fistulas.

METHODS

This is a retrospective analysis of 21 patients who presented with a symptomatic Crohn's perianal fistula. Patients were enrolled in a clinical practice protocol of serial EUS exams. All patients underwent a baseline rectal EUS and were placed on maximal medical treatment with 6-mercaptopurine (6-MP) or azathioprine, Cipro, and infliximab (5 mg/kg at 0, 2, and 6 wk and then every 8 wk). Patients were also assessed at baseline by a colorectal surgeon who was aware of the EUS findings. Seton placement and incision and drainage were performed when appropriate. Serial EUS examinations were performed, and the findings were used to guide therapy (i.e., the presence of fistula healing on EUS was used to guide seton removal, discontinuation of infliximab, and Cipro).

RESULTS

In the 21 patients enrolled, the median duration of active perianal symptoms was 9 wks (1-36). 10 patients (48%) had previous perianal surgery and 5 (24%) had received infliximab previously. The fistulas treated included 8 trans-sphincteric, 2 superficial, 3 recto-vaginal, and 7 with multiple and horseshoe fistulas. 13 patients (62%) had associated abscesses at presentation. Eighteen of 21 patients (86%) had complete cessation of drainage initially. Median time to cessation of drainage was 10.6 weeks (range, 4-32 wk). Sixteen of 21 patients (76%) maintained long-term cessation of drainage. The median length of follow-up was 68 weeks (range, 35-101 wk). No abscess developed during treatment in any patient. EUS evidence of persistent fistula activity was seen in 10 patients (48%). Of the 11 patients (52%) in whom EUS showed no persistent fistula activity, 7 (64%) have maintained fistula closure off of infliximab and Cipro. Median duration from last infliximab infusion was 47 weeks (range, 20-80 wk). The remaining 4 patients continued infliximab to maintain remission of their luminal disease. Only 1 patient with a horseshoe fistula showed complete healing on EUS.

CONCLUSION

In conclusion, using EUS to guide therapy for Crohn's perianal fistulas with infliximab, an immunosuppressive, and an antibiotic is associated with a high short and long-term fistula response rate. EUS may identify a subset of patients who can discontinue infliximab without recurrence of fistula drainage.