Guidelines for medical treatment of Crohn's perianal fistulas: critical evaluation of therapeutic trials

Assessment of perianal fistulizing Crohn’s disease activity with endoanal ultrasound: A retrospective cohort study

BACKGROUND

Perianal fistulas pose dual challenges to Crohn's disease (CD) patients. Low patient compliance due to the complexity of existing examination methods plagues the treatment and follow-up management of perianal CD.

AIM

To determine the accuracy of endoanal ultrasound (EUS) and shear wave elastography (SWE) for evaluating perianal fistulizing CD (PFCD) activity.

METHODS

This was a retrospective cohort study. A total of 67 patients from August 2022 to December 2023 diagnosed with CD were divided into three groups: Non-anal fistula group (n = 23), low-activity perianal fistulas [n = 19, perianal disease activity index (PDAI) ≤ 4], high-activity perianal fistulas (n = 25, PDAI > 4) based on the PDAI. All patients underwent assessments including EUS + SWE, pelvic magnetic resonance [pelvic magnetic resonance imaging (MRI)], C-reactive protein, fecal calprotectin, CD activity index, PDAI.

RESULTS

The percentage of fistulas indicated by pelvic MRI and EUS was consistent at 82%, and there was good consistency in the classification of perianal fistulas (Kappa = 0.752, P < 0.001). Significant differences were observed in the blood flow Limberg score (χ² = 8.903, P < 0.05) and shear wave velocity (t = 2.467, P < 0.05) between group 2 and 3. Shear wave velocity showed a strong negative correlation with magnetic resonance novel index for fistula imaging in CD (Magnifi-CD) score (r = -0.676, P < 0.001), a weak negative correlation with the PDAI score (r = -0.386, P < 0.05), and a weak correlation between the Limberg score and the PDAI score (r = 0.368, P < 0.05).

CONCLUSION

EUS combined with SWE offers a superior method for detecting and quantitating the activity of perianal fistulas in CD patients. It may be the ideal tool to assess PFCD activity objectively for management strategies.

Leukocyte dysfunction and reduced CTLA-4 expression are associated with perianal Crohn's disease

Although perianal Crohn's disease (PCD) is highly associated with the exacerbated inflammation, the molecular basis and immunological signature that distinguish patients who present a history of perianal lesions are still unclear. This paper aims to define immunological characteristics related to PCD. In this cross-sectional observational study, we enrolled 20 healthy controls and 39 CD patients. Blood samples were obtained for the detection of plasma cytokines and lipopolysaccharides (LPS). Peripheral blood mononuclear cells (PBMCs) were phenotyped by flow cytometry. Leukocytes were stimulated with LPS or anti-CD3/anti-CD28 antibodies. Our results show that CD patients had augmented plasma interleukin (IL)-6 and LPS. However, their PBMC was characterized by decreased IL-6 production, while patients with a history of PCD produced higher IL-6, IL-8, and interferon-γ, along with decreased tumor necrosis factor alpha (TNF). CD patients had augmented FoxP3 and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) regulatory markers, though the PCD subjects presented a significant reduction in CTLA-4 expression. CTLA-4 as well as IL-6 and TNF responses were able to distinguish the PCD patients from those who did not present perianal complications. In conclusion, IL-6, TNF, and CTLA-4 exhibit a distinct expression pattern in CD patients with a history of PCD, regardless of disease activity. These findings clarify some mechanisms involved in the development of the perianal manifestations and may have a great impact on the disease management.

Differences in Gut Microbiota between Healthy Individuals and Patients with Perianal Abscess before and after Surgery

Surgery is the most important treatment for perianal abscesses. However, the gut microbiota of patients with perianal abscess and the effects of perianal abscess on the gut microbiota after surgery are unknown. In this study, significant changes in interleukin 6 and tumor necrosis factor-α in the blood of healthy subjects, patients with perianal abscesses, and patients after perianal abscess surgery were identified. 16S rRNA gene sequencing technology was used to detect the changes in the gut microbiota among 30 healthy individuals and 30 patients with perianal abscess before and after surgery. Venn diagrams and alpha diversity analyses indicated differences in the abundance and uniformity of gut microbiota between the healthy individuals and patients with perianal abscesses before and after surgery. Beta diversity analysis indicated that the grouping effects among the control, abscess, and surgery groups were good. The classification and compositional analysis showed significant differences in the gut microbiota between healthy individuals and patients with perianal abscesses before and after surgery. LEfSe analysis, random forest analysis, and ROC curve analysis showed that Klebsiella (AUC = 0.7467) and Bilophila (AUC = 0.72) could be potential biomarkers for the diagnosis of perianal abscess. The functional prediction results showed that the differential microbiota is significantly enriched in the pathways related to nutrition and drug metabolism. This study may have important implications for the clinical management and prognostic assessment of patients with perianal abscesses.

Disease- and Medication-Specific Differences of the Microbial Spectrum in Perianal Fistulizing Crohn's Disease-Relevant Aspects for Antibiotic Therapy

Perianal fistulizing Crohn's Disease (CD) with abscess formation represents an aggressive phenotype in Inflammatory Bowel Disease (IBD) with increased morbidity. Treatment is multidisciplinary and includes antibiotics, but knowledge about the microbial spectrum is rare often resulting in inadequate antimicrobial therapy. In this single center retrospective study, all patients who were operated due to perianal abscess formation were retrospectively analyzed and the microbial spectrum evaluated. Patients were divided into a CD and non-CD group with further subgroup analysis. 138 patients were finally included in the analysis with 62 patients suffering from CD. Relevant differences were detected for the microbial spectrum with anaerobic bacteria being significantly more often isolated from non-CD patients. In a subgroup-analysis of CD patients only, medical therapy had a relevant effect on the microbial spectrum since Streptococcus groups and Enterobacterales were significantly more often isolated in patients treated with steroids compared to those being treated by antibodies. In conclusion, the microbial spectrum of patients suffering from CD varies significantly from non-CD patients and immunosuppressive medication has a relevant effect on isolated pathogens. Based on that, adaption of antibiotic treatment might be discussed in the future.

Evaluation of guidelines for the management of perianal fistulas in Crohn's disease

INTRODUCTION

The occurrence of perineal fistula is a significant evesnt in the evolution of Crohn's disease. Approximately 21% to 23% of patients develop perineal fistula at least once in their lifetime, approximately 30% of patients have cases of recurrence, and the refractory and recurrent perineal lesions of Crohn's disease impose a great economic burden on patients. The main purpose of this review was to investigate the quality of guidelines for perineal fistula in Crohn's disease.

AREA COVERED

Relevant websites and databases were systematically searched to identify and select clinical guidelines related to perineal fistulas in Crohn's disease. Four independent reviewers assessed the eligible guidelines using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) and used intraclass correlation coefficients (ICC) to measure the agreement among the guideline reviewers.

CONCLUSION

There is much room for improvement in the quality of guidelines for the management of perineal fistulas in Crohn's disease. The recommendations and evidence for guidelines for the management of perineal fistulas in Crohn's disease are quite heterogeneous, and guideline-developers would be well advised to address the above issues during future guideline development.

Predictors of long-term outcomes of radiologically defined perianal fistulizing Crohn's disease treated with antitumor necrosis factor-alpha agents based on Parks' classification

BACKGROUND AND AIMS

Perianal fistulizing Crohn's disease (PFCD) leads to significant disability. Data assessing healing of complex PFCD based on pelvic MRI using Parks' classification remains sparse. We aimed to assess the frequency of closure of fistula tract on MRI in patients treated with antitumor necrosis factor alpha antagonists and identify predictors of poor response.

MATERIALS AND METHODS

We retrospectively identified patients registered in the Saudi Inflammatory Bowel Disease Information System registry, who were diagnosed as PFCD based on MRI and treated with infliximab or adalimumab. Fistulae were classified based on Parks' classification and response to treatment was determined as full, partial, or no response, after at least 12 months of treatment.

RESULTS

Out of 960 patients, 61 had complex PFCD that required treatment with an anti-TNF agent. The median age was 27 years (range: 14-69 years) and the median duration of disease was 6.2 ± 5.8 years. A full response to treatment was achieved in 27 (44.4%), whereas 10 patients (16.3%) had partial response and 24 (39.3%) had no response. On univariable analysis, a statistically significant association was observed between poor fistula response and low BMI, rectal involvement, fistulae classification, and the presence of an abscess. According to multivariable regression, only low BMI predicted poor fistulae outcome (odds ratio = 1.37, 95% confidence interval: 0.69-0.98).

CONCLUSION

Less than half of this cohort of patients with PFCD achieved complete radiological fistula healing with anti-TNF therapy. Low BMI appears to be the only predictor of poor outcome.

Strategies to Optimize Anti-tumor Necrosis Factor Therapy for Perianal Fistulizing Crohn's Disease: A Systematic Review

Tumor necrosis factor (TNF) antagonists are considered the cornerstone therapy for fistulizing perianal Crohn's disease (PCD), yet a substantial proportion of patients fail to achieve healing. Therefore, we reviewed the evidence for strategies to enhance the efficacy of TNF antagonists for PCD. A systematic search of electronic databases through July 2018 was performed to identify studies that assessed the effectiveness of TNF antagonists combined with another medical or surgical intervention for PCD; or assessed the association between anti-TNF serum concentrations and fistula healing. Twelve studies compared anti-TNF therapy alone versus a combined approach: four with surgery, three with antibiotics, and five with immunomodulators. Only two studies, both with antibiotics, were rated high quality. The addition of antibiotics to anti-TNF therapy resulted in significantly higher rates of fistula response and healing in one study, and a trend toward reduction in fistula drainage in the other. Three of four studies found higher rates of fistula healing when surgery was combined with TNF antagonists. In contrast, one of five studies found a trend toward higher rates of fistula healing in patients treated concomitantly with immunomodulators. Five observational studies assessed the association between anti-TNF concentration and fistula healing. Higher infliximab serum concentrations were consistently associated with fistula healing. In conclusion, few high-quality studies assessing strategies to optimize anti-TNF therapy for PCD exist. Although antibiotics, possibly surgery, and higher serum infliximab concentrations appear to improve fistula healing, future prospective studies are needed to determine the optimal treatment strategy.

Perianal Crohn's Disease

This article provides an overview of the principles in the evaluation and management of perianal Crohn's disease (CD). Manifestation-specific treatment is addressed including abscess, fistula, skin tags, hemorrhoids, fissure, ulcers, strictures, ano-, and rectovaginal fistulas as well CD-associated hidradenitis suppurativa.

Identifying perianal fistula complications in pediatric patients with Crohn's disease using administrative claims

Background

Although perianal fistulas occur commonly in pediatric Crohn’s disease (CD), evaluations of health services have been limited since no validated claims-based methods exist for identifying cases.

Objective

To develop and validate accurate case definitions for perianal fistulas among pediatric patients with CD from administrative claims.

Methods

Retrospective cohort study in which we developed and tested candidate case definitions for perianal fistula. Patients (age 5–21 years between 2005–2012) with CD enrolled in Michigan Medicaid with healthcare at University of Michigan were identified via claims. Medical records were obtained from all identified patients, whose entire records were abstracted. Medical record evidence for perianal fistula was considered the “gold standard” against which candidate case definitions were compared. The reference case definition of perianal fistula (ICD9 565.1) and candidate case definitions were evaluated.

Results

Of 843 patients identified via claims, 274 (33%) met CD criteria for inclusion. The true perianal fistula rate among CD patients was 18% (n = 49). The top-performing candidate case definition identified 15% (n = 42), had sensitivity of 77.6%, specificity of 98.2%, positive predictive value (PPV) 90.5%, negative predictive value (NPV) 95.3%, and area under receiver operator characteristic curve (ROC) of 0.88. In contrast, the reference case definition identified 9% (n = 26), sensitivity 51.0%, specificity 99.6%, PPV 96.2%, NPV 90.3%, and had an area under ROC of 0.75.

Conclusions

We demonstrated that it is feasible to use administrative claims data to accurately identify pediatric patients with perianal fistula complications. Claims-based case definitions were found to be highly accurate through medical record review, providing a high degree of confidence for future studies where chart review is not feasible. These claims-based methods can be applied to claims data in other settings for the evaluation of health services utilization as well as to assess the comparative effectiveness of prevention and treatment strategies.

Recent advances in the management of perianal fistulizing Crohn's disease: lessons for the clinic

Managing fistulizing perianal disease is among the most challenging aspects of treating patients with Crohn's disease. Perianal fistulas are indicative of poor long-term prognosis. They are commonly associated with significant morbidities and can have detrimental effects on quality of life. While durable fistula closure is ideal, it is uncommon. In optimal circumstances, reported long-term fistula healing rates are only slightly higher than 50% and recurrence is common. Achieving these results requires a combined medical and surgical approach, highlighting the importance of a highly skilled and collaborative multidisciplinary team. In recent years, advances in imaging, biologic therapies and surgical techniques have lent to growing enthusiasm amongst treatment teams, however the most advantageous approach is yet to be determined. Areas covered: Here we review current management approaches, incorporating recent guidelines and novel therapies. Additionally, we discuss recently published and ongoing studies that will likely impact practice in the coming years. Expert opinion: Investing in concerted collaborative multi-institutional efforts will be necessary to better define optimal timing and dosing of medical therapy, as well as to identify ideal timing and approach of surgical interventions. Standardizing outcome measures can facilitate these efforts. Clearly, experienced multidisciplinary teams will be paramount in this process.

Darvadstrocel: A Review in Treatment-Refractory Complex Perianal Fistulas in Crohn's Disease

Darvadstrocel (Alofisel^®) consists of a suspension of expanded human allogeneic adipose-derived mesenchymal stem cells (eASCs). It is the first mesenchymal stem cell (MSC) advanced therapy approved in the EU for the treatment of complex perianal fistulas in adult patients with non-active/mildly active luminal Crohn's disease, when fistulas have shown an inadequate response to ≥ 1 conventional or biologic therapy. In the pivotal phase 3 ADMIRE-CD trial in this difficult-to-treat patient population, after standard-of-care fistula conditioning, add-on therapy with a single dose of darvadstrocel (120 million eASC) administered into the tissue surrounding complex perianal fistulas was significantly more effective than placebo (saline), with the darvadstrocel group having a higher combined remission rate (i.e. clinically-assessed fistula closure plus MRI-assessed absence of abscesses) at 24 weeks in intent-to-treat (ITT primary analysis), modified ITT and per-protocol analyses. Clinical remission was maintained in > 50% of patients at 52 weeks' follow-up. Given the very limited treatment options available for this difficult-to-treat rare condition, darvadstrocel is a promising, novel, minimally invasive therapy that represents an important advance in the therapeutic options for complex perianal fistulas in adult patients with non-active/mildly active luminal Crohn's disease when fistulas have shown an inadequate response to ≥ 1 conventional or biologic therapy.

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.

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.

A comprehensive review and update on Crohn's disease

The term inflammatory bowel disease (IBD) refers principally to two major categories of chronic relapsing inflammatory intestinal disorders: Crohn's disease (CD) and ulcerative colitis (UC). In the United States, it is currently estimated that about 1.5 million people suffer from IBD, causing considerable suffering, mortality and economic loss every year. Yet the cause of IBD is unknown, and until we understand more, prevention or cure will not be possible. There is a lot of variation in the incidence and prevalence of CD based on geographic region, environment, immigrant population, and ethnic groups. The annual incidence of CD in North America is reported to be 3.1-20.2 per 100,000 with a prevalence of 201 per 100,000 population. Based on the epidemiological, genetic and immunological data, CD is considered to be a heterogeneous disorder with multifactorial etiology in which genetics and environment interact to manifest the disease. Several genes have been studied so for with respect to CD, but thus far the strong and replicated associations have been identified with NOD2, IL23R and ATG16L1 genes. The risk factors implicated with CD include smoking, low fiber- high carbohydrate diet, altered microbiome and medications such as non-steroidal anti-inflammatory drugs. CD is typically characterized by transmural inflammation of the intestine and could affect any part of the gastrointestinal tract from mouth to perianal area. In terms of distribution of the disease 25% of the patients have colitis only, 25% is ileitis only and 50% have ileocolitis. The Montreal classification is based on the age at diagnosis (<16, 17-40, > 40), disease location (Ileal, colonic, Ileocolonic) and the disease behavior (nonstricturing/nonpenetrating, stricturing, penetrating). The key features for diagnosing CD comprises a combination of radiographic, endoscopic and pathological findings demonstrating focal, asymmetric, transmural or granulomatous features. Abdominal Computed tomography (CT) enterography is the most preferred first-line radiologic study used in the assessment of small bowel CD. The diagnostic accuracy of magnetic resonance enterography/enteroclysis is similar to that of CT scans and also prevents exposure to ionizing radiation. Endoscopic scores are considered to be the gold standard tool to measure the activity of CD and they are used more commonly in the clinical trials to measure the efficacy of various drugs on inducing and maintaining mucosal healing. The most common scoring systems used to measure clinical disease activity include Crohn's Disease Activity Index (CDAI), HBI- Harvey-Bradshaw index (HBI), short inflammatory bowel disease questionnaire (SIBDQ) and Lehmann score. Management of Crohn's disease has been seen as an evolving challenge owing to its widely heterogeneous manifestations, overlapping characteristics with other inflammatory disorders, often elusive extraintestinal manifestations and uncertain etiology. Therapeutic interventions are tailored to address symptomatic response and subsequent tolerance of the intervention. Chronology of treatment should favor treatment dose acute disease or "induction therapy", followed by maintenance of adequate response or remission, i.e. "maintenance therapy". The medications which are highly effective in inducing remission include steroids and Tumor Necrosis Factor (TNF) inhibitors. Medications used to maintain remission include 5-aminosalicyclic acid products, immunomodulators (Azathioprine, 6-mercaptopurine, methotrexate) and TNF inhibitors (infliximab, adalimumab, certolizumab and golimumab). Surgical interventions like bowel resection, stricturoplasty or drainage of abscess is required in up to two thirds of CD patients during their lifetime. The most common indications for surgical resection are medically refractory disease, perforation, persisting or recurrent obstruction, abscess not amenable to percutaneous drainage, intractable hemorrhage, dysplasia or cancer. Endoscopic recurrence in postoperative CD patients, as defined by Rutgeers score i2-i4 occur in 30-90% of the patients at the neoterminal ileum within 12 months of surgery and almost universally by 5 years. Treating CD requires a comprehensive care team including the patient, primary care provider, and gastroenterologist. In summary CD is a chronic inflammatory condition with a remitting and relapsing course primarily affecting relatively younger population with significant socioeconomic effects.

The Use of Temporary Fecal Diversion in Colonic and Perianal Crohn's Disease Does Not Improve Outcomes

AIMS

To determine whether temporary fecal diversion for refractory colonic and/or perianal Crohn's disease can lead to clinical remission and restoration of intestinal continuity after optimization of medical therapy.

METHODS

We retrospectively reviewed our prospectively maintained database of patients treated at the University of Maryland for Crohn's disease between May 2004 and July 2014. Patients with colonic, perianal, or colonic and perianal Crohn's disease, who had fecal diversion for control of medically refractory and/or severe disease, were included. Outcomes, including disease activity and rate of ileostomy reversal, were evaluated up to 24 months from stoma formation.

RESULTS

Thirty patients were identified. Fecal diversion was performed for perianal disease in 37%, colonic disease in 33%, and both in 30% of patients. Twelve (40%) patients underwent ileostomy reversal. Twenty-five percent of patients with perianal disease had their ostomies reversed compared to 70% of patients with colonic disease alone. More patients with complex compared to simple perianal disease remained diverted (p = 0.02). Six (20%) patients required colectomy. Of these, 50% had complex perianal disease, all had received two or more biologics, and two-thirds were on combination therapy pre-diversion.

CONCLUSIONS

Our study found that nearly two-thirds of patients with medically refractory colonic and/or severe perianal Crohn's disease treated with fecal diversion and optimization of postoperative medical therapy remain diverted or require colectomy within two years after ileostomy formation. In patients with severe, refractory perianal disease and those treated with combination therapy and >1 biologic exposure pre-diversion, colectomy rather than temporary fecal diversion should be considered.

Crohn Disease: Epidemiology, Diagnosis, and Management

Crohn disease is a chronic idiopathic inflammatory bowel disease condition characterized by skip lesions and transmural inflammation that can affect the entire gastrointestinal tract from the mouth to the anus. For this review article, we performed a review of articles in PubMed through February 1, 2017, by using the following Medical Subject Heading terms: crohns disease, crohn's disease, crohn disease, inflammatory bowel disease, and inflammatory bowel diseases. Presenting symptoms are often variable and may include diarrhea, abdominal pain, weight loss, nausea, vomiting, and in certain cases fevers or chills. There are 3 main disease phenotypes: inflammatory, structuring, and penetrating. In addition to the underlying disease phenotype, up to a third of patients will develop perianal involvement of their disease. In addition, in some cases, extraintestinal manifestations may develop. The diagnosis is typically made with endoscopic and/or radiologic findings. Disease management is usually with pharmacologic therapy, which is determined on the basis of disease severity and underlying disease phenotype. Although the goal of management is to control the inflammation and induce a clinical remission with pharmacologic therapy, most patients will eventually require surgery for their disease. Unfortunately, surgery is not curative and patients still require ongoing therapy even after surgery for disease recurrence. Importantly, given the risks of complications from both Crohn disease and the medications used to treat the disease process, primary care physicians play an important role in optimizing the preventative care management to reduce the risk of complications.

Pediatric Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), including Crohn disease, ulcerative colitis, and IBD-unspecified, is a chronic immune-mediated condition of the gastrointestinal tract in which the goal of treatment is to induce and maintain durable remission. In pediatrics, there is a wide spectrum of presenting symptoms, but esophagogastroduodenoscopy and colonoscopy are imperative to confirming the diagnosis. Treatment goals include achieving mucosal healing of the gastrointestinal tract, reaching growth potential, limiting medication toxicities, and optimizing quality of life for all patients.

Association of Induction Infliximab Levels With Clinical Response in Perianal Crohn's Disease

BACKGROUND

The association of infliximab [IFX] trough levels with clinical and endoscopic outcomes in inflammatory bowel disease is well established. However, there is scarce data regarding the association of perianal fistula response with IFX. The aim of this study was to establish whether early induction infliximab levels and anti-infliximab antibodies [ATIs] are associated with perianal fistula response.

METHODS

Consecutive CD patients with perianal fistulae that were treated with IFX between 2008 and 2016 were included in the study. Response was defined as cessation or significant improvement of fistula drainage. Patients with unavailable IFX level or ATI measurements and/or missing clinical follow-up at Week 14 were excluded.

RESULTS

A total of 36 patients with perianal fistulae were included; 25/36 [69.4%] responded to treatment by Week 14. The median induction IFX levels at Weeks 2, 6 and 14 in the responders group at Week 14 were higher compared with those of the non-responders group [20/5.6 µg/mL, P = 0.0001; 13.3/2.55 µg/mL P = 0.0001; 4.1/0.14 µg/mL, P = 0.01]. On multivariate analysis, IFX leve at Weeks 2 and 6 were significantly associated with fistula response at Weeks 14 and 30. IFX drug levels of 9.25 µg/mL at Week 2 and 7.25 µg/mL at Week 6 were the best predictors of fistula response.

CONCLUSION

High IFX trough levels during induction are associated with favorable fistula response to anti-TNF treatment. If validated in a larger prospective study, our findings may help guide anti-TNF treatment in patients with perianal CD, and suggest serum level-guided treatment escalation in non-responders or prompt changing of biologic treatment in non-responders.

Management of complex perianal Crohn's disease

Patients with Crohn's disease often develop perianal disease, successfully managed in most cases. However, its most aggressive form, complex perianal disease, is associated with high morbidity and a significant impairment in patients' quality of life. The aim of this review is to provide an updated approach to this condition, reviewing aspects of its epidemiology, diagnosis and therapeutic alternatives. Emerging treatment options are also discussed. A multidisciplinary assessment of these patients with a coordinated medical and surgical approach is crucial.