Treat to target or 'treat to clear' in inflammatory bowel diseases: one step further?

An artificial intelligence-driven scoring system to measure histological disease activity in ulcerative colitis

BACKGROUND AND AIMS

Assessment and scoring of histological images in Ulcerative colitis (UC) is prone to inter- and intra-observer variability. This study aimed to investigate whether an artificial intelligence (AI) system developed using image processing and machine learning algorithms could measure histological disease activity based on the Nancy index.

METHODS

A total of 200 histological images of patients with UC were used in this study. A novel AI algorithm was developed using state-of-the-art image processing and machine learning algorithms based on deep learning and feature extraction. The cell regions of each image, followed by the Nancy index, were manually annotated and measured independently by four histopathologists. Manual and AI-automated measurements of the Nancy index score were conducted and assessed using the intraclass correlation coefficient (ICC).

RESULTS

The 200-image dataset was divided into two groups (80% was used for training and 20% for testing). Intraclass correlation coefficient statistical analyses were performed to evaluate the AI tool and used as a reference to calculate the accuracy. The average ICC among the histopathologists was 89.3 and the average ICC between histopathologists and the AI tool was 87.2. The AI tool was found to be highly correlated with histopathologists.

CONCLUSIONS

The high correlation of performance of the AI method suggests promising potential for inflammatory bowel disease clinical applications. A standardized automated histological AI-driven scoring system can potentially be used in daily inflammatory bowel disease practice to reduce training needs and resource use, eliminate the subjectivity of the pathologists, and assess disease severity for treatment decisions.

The Burden of Work Productivity and Activity Impairment in Patients with Psoriasis, Psoriatic Arthritis, Ulcerative Colitis, and Crohn's Disease

BACKGROUND

Comparisons among autoimmune diseases enable understanding of the burden and factors associated with work productivity loss and impairment.

AIMS

The objective was to compare work productivity and activity and associated factors among patients with inflammatory bowel diseases and other autoimmune conditions.

METHODS

This cross-sectional study included employed, adult patients (age 20-64 years) in the CorEvitas Inflammatory Bowel Disease, Psoriasis, and Psoriatic Arthritis/Spondyloarthritis Registries between 5/2017 and 6/2020. Any patient-reported impairment on four domains of the Work Productivity and Activity Index (WPAI) was collected across registries. Prevalence for each autoimmune disease was reported and stratified by disease activity using direct age-sex-standardization. Factors associated with the presence of any WPAI were identified in logistic regression models.

RESULTS

A total of 7,169 patients with psoriasis (n = 4,768, 67%), psoriatic arthritis (n = 1,208, 17%), Crohn's disease (CD, n = 621, 9%), and ulcerative colitis (UC, n = 572, 8%) met inclusion criteria. Among patients not in remission across all disease cohorts, the age-sex-standardized prevalence of any presenteeism, work productivity loss, and activity impairment ranged from 54 to 97%. Patients with CD in remission had higher standardized prevalence of presenteeism (53% [48-57%]) and work productivity loss (54% [49-59%]), compared to those from other cohorts (presenteeism [range: 33-39%] and work productivity loss [range: 37-41%]). For all WPAI domains, the strongest adjusted associations were for moderate to severe disease activity and psychosocial symptoms.

CONCLUSIONS

Patients with moderate to severe disease activity reported the highest WPAI burden. However, patients in remission or mild disease activity also report some WPAI burden, emphasizing a multidisciplinary treatment approach to improve work productivity loss and impairment.

Histologic assessments in ulcerative colitis: the evidence behind a new endpoint in clinical trials

INTRODUCTION

Treatment goals for ulcerative colitis (UC) are evolving from the achievement of clinical remission to more rigorous goals defined by endoscopic and histologic healing. Achievement of deeper remission targets aims to reduce the risk of colectomy, hospitalizations, and colorectal cancer.

AREAS COVERED

This review covers histologic assessments, histologic remission as a clinical trial endpoint, and the association between histologic disease activity and clinical outcomes. Future directions are also discussed, including the use of advanced imaging and artificial intelligence technologies, as well as potential future treatment targets beyond histologic remission.

EXPERT OPINION

Histologic assessments are used for their sensitivity in measuring mucosal inflammatory changes in UC. Due to correlation with disease activity, histologic assessments may support clinical decision-making regarding treatment decisions as such assessments can be associated with rates of clinical relapse, hospitalization, colectomy, and neoplasia. While histologic remission is limited by varying definitions and multiple histologic indices, work is ongoing to create a consensus on the use of histologic assessments in clinical trials. As research advances, aspirational targets beyond histologic remission, such as molecular healing and disease clearance, are being explored.

Mesalazine granules promote disease clearance in patients with mild-to-moderate ulcerative colitis

BACKGROUND

Over the past decade, treatment targets for ulcerative colitis (UC) have become more stringent, incorporating multiple parameters. Recently, the concept of 'disease clearance'-defined as combined clinical, endoscopic, and histological remission-has been proposed as an ultimate endpoint in treating UC.

OBJECTIVE

To determine the rates of disease clearance in patients with mild-to-moderate UC treated with different doses of mesalazine granules as induction therapy.

METHODS

In a post hoc analysis, data were pooled from four randomised, active-controlled, phase 3 clinical trials in patients with mild-to-moderate UC receiving 8-week induction therapy with mesalazine granules at daily doses of 1.5, 3.0 or 4.5 g. Rates of clinical, endoscopic, and histological remission were determined using stringent criteria and used to calculate rates of the composite endpoints of clinical plus endoscopic remission, endoscopic plus histological remission, and disease clearance (clinical plus endoscopic plus histological remission).

RESULTS

A total of 860 patients were included in the analysis. Among the total population, 20.0% achieved disease clearance with mesalazine granules: 13.1% in patients receiving 1.5 g mesalazine granules/day, 21.8% in those receiving 3.0 g/day and 18.9% in those receiving 4.5 g/day. Among patients with moderate UC, 16.8% achieved disease clearance: 7.1% with 1.5 g/day, 18.8% with 3.0 g/day and 16.2% with 4.5 g/day.

CONCLUSION

Disease clearance, proposed to be predictive of improved long-term outcomes, can be achieved in a clinically meaningful proportion of mild-to-moderate UC patients treated with mesalazine granules. A daily dose of 3.0 g appears optimal to reach this target.

A mannitol-modified emodin nano-drug restores the intestinal barrier function and alleviates inflammation in a mouse model of DSS-induced ulcerative colitis

BACKGROUND

Ulcerative colitis (UC) is an inflammatory disease of the colon that is characterized by mucosal ulcers. Given its increasing prevalence worldwide, it is imperative to develop safe and effective drugs for treating UC. Emodin, a natural anthraquinone derivative present in various medicinal herbs, has demonstrated therapeutic effects against UC. However, low bioavailability due to poor water solubility limits its clinical applications.

METHODS

Emodin-borate nanoparticles (EmB) were synthesized to improve drug solubility, and they modified with oligomeric mannitol into microgels (EmB-MO) for targeted delivery to intestinal macrophages that express mannose receptors. UC was induced in a mouse model using dextran sulfate sodium (DSS), and different drug formulations were administered to the mice via drinking water. The levels of inflammation-related factors in the colon tissues and fecal matter were measured using enzyme-linked immunosorbent assay. Intestinal permeability was evaluated using fluorescein isothiocyanate dextran. HE staining, in vivo imaging, real-time PCR, and western blotting were performed to assess intestinal barrier dysfunction.

RESULTS

Both EmB and EmB-MO markedly alleviated the symptoms of UC, including body weight loss, stool inconsistency, and bloody stools and restored the levels of pro- and anti-inflammatory cytokines. However, the therapeutic effects of EmB-MO on the macroscopic and immunological indices were stronger than those of EmB and similar to those of 5-aminosalicylic acid. Furthermore, EmB-MO selectively accumulated in the inflamed colon epithelium and restored the levels of the gut barrier proteins such as ZO-1 and Occludin.

CONCLUSIONS

EmB-MO encapsulation significantly improved water solubility, which translated to greater therapeutic effects on the immune balance and gut barrier function in mice with DSS-induced UC. Our findings provide novel insights into developing emodin-derived drugs for the management of UC.

ABX464 (Obefazimod) Upregulates miR-124 to Reduce Proinflammatory Markers in Inflammatory Bowel Diseases

Advanced therapies have transformed the treatment of inflammatory bowel disease; however, many patients fail to respond, highlighting the need for therapies tailored to the underlying cell and molecular disease drivers. The first-in-class oral molecule ABX464 (obefazimod), which selectively upregulates miR-124, has demonstrated its ability to be a well-tolerated treatment with rapid and sustained efficacy in patients with ulcerative colitis (UC). Here, we provide evidence that ABX464 affects the immune system in vitro , in the murine model of inflammatory bowel disease, and in patients with UC. In vitro , ABX464 treatment upregulated miR-124 and led to decreases in proinflammatory cytokines including interleukin (IL) 17 and IL6, and in the chemokine CCL2. Consistently, miR-124 expression was upregulated in the rectal biopsies and blood samples of patients with UC, and a parallel reduction in Th17 cells and IL17a levels was observed in serum samples. In a mouse model of induced intestinal inflammation with dextran sulfate sodium, ABX464 reversed the increases in multiple proinflammatory cytokines in the colon and the upregulation of IL17a secretion in the mesenteric lymph nodes. By upregulating miR-124, ABX464 acts as "a physiological brake" of inflammation, which may explain the efficacy of ABX464 with a favorable tolerability and safety profile in patients with UC.

Treatment escalation and de-escalation decisions in Crohn's disease: Delphi consensus recommendations from Japan, 2021

BACKGROUND

We aimed to develop criteria for treatment intensification in patients with (1) luminal Crohn's disease (CD), (2) CD with perianal disease and/or fistula, (3) CD with small bowel stenosis, (4) in the postoperative setting, and (5) for discontinuing or reducing the dose of treatment in patients with CD.

METHODS

PubMed and Embase were searched for studies published since 1998 which may be relevant to the five defined topics. Results were assessed for relevant studies, with preference given to data from randomized, controlled studies. For each question, a core panel of 12 gastroenterologists defined the treatment target and developed statements, based on the literature, current guidelines, and relevant additional studies. The evidence supporting each statement was graded using the Oxford Centre for Evidence-Based Medicine: Levels of Evidence (March 2009). A modified Delphi process was used to refine statements and gain agreement from 54 Japanese specialists at in-person and online meetings conducted between October 2020 and April 2021.

RESULTS

Seventeen statements were developed for treatment intensification in luminal CD (targeting endoscopic remission), six statements for treatment intensification in perianal/fistulizing CD (targeting healing of perianal lesions and complete closure of the fistula), six statements for treatment intensification in CD with small bowel stenosis (targeting resolution of obstructive symptoms), seven statements for treatment intensification after surgery (targeting endoscopic remission), and five statements for discontinuing or reducing the dose of treatment in patients with CD.

CONCLUSIONS

These statements provide guidance on how and when to intensify or de-intensify treatment for a broad spectrum of patients with CD.

Qing-Chang-Hua-Shi granule ameliorates DSS-induced colitis by activating NLRP6 signaling and regulating Th17/Treg balance

BACKGROUND

Chinese herbal medicine Qing-Chang-Hua-Shi granule (QCHS) is widely used to treat ulcerative colitis in China. However, the molecular mechanisms of QCHS remains largely unknown.

PURPOSE

To assess the therapeutic effects of QCHS on colitis and to reveal its mechanisms of action.

METHODS

The main components of QCHS were identified using a UHPLC-QTOF-MS method and the efficacy of QCHS was evaluated using an DSS-induced mice model. The inflammatory responses and mucosal integrity in colon were comprehensively assessed. Flow cytometry was used to analysis the proportion of Th17 and Treg cells. Detect the signal transduction of the NOD-like receptor family pyrin domain containing 6 (NLRP6) both in vitro and in vivo. Furthermore, siNLRP6 transfection was used to validate the functional targets of QCHS.

RESULTS

QCHS treatment significantly alleviated colitis in mice by improving symptoms and pathological damage. Moreover, QCHS treatment suppressed the inflammatory response and preserved the integrity of colon tissue. Most importantly, QCHS balanced the Th17/Treg response of UC mice. Mechanistically, by activating NLRP6 inflammasome pathway, QCHS regulated the maturation of interleukin (IL)-1β and IL-18 to affect inflammation and drive Th17 cell differentiation.

CONCLUSIONS

The effect of QCHS on UC mice is dose-dependent, with high-dose QCHS being superior to 5-Aminosalicylic acid (200 mg/kg/day). QCHS acts through the NLRP6 signaling pathway to modulate Th17/Treg balance, resulting in the protective effects against colitis. This study investigated the relevant pharmacological mechanisms of QCHS, providing further evidence for the application of QCHS in UC treatment.

Predicting Histological Healing and Recurrence in Ulcerative Colitis by Assessing Mucosal Vascular Pattern Under Narrow-Band Imaging Endoscopy

This study investigated the predictive value of narrow-band imaging (NBI) endoscopic staging of different mucosal vascular patterns (MVPs) in patients with ulcerative colitis (UC) for histological healing or clinical recurrence of patients with UC. A total of 124 patients with UC in clinical remission attending the First Affiliated Hospital of Weifang Medical College were included in the study and underwent NBI colonoscopy. Inflammatory activity was assessed in the intestine using the Mayo endoscopic score (MES) and the MVP. Mucosal inflammation was histologically graded using the Nancy index (NI). The colons of 124 patients with UC were staged according to NBI endoscopic MVP staging criteria. The differences between NBI colonoscopy MVP typing and white light endoscopic MES in assessing histological healing (HH) were statistically significant (p < 0.001), and there was a moderate correlation between MES and the degree of HH (r = 0.471, p < 0.001). In addition, there was a significant correlation between the severity of mucosal activity determined by white light endoscopy (WLE) and MVP staging (r = 0.811, p < 0.001). The differences between NBI endoscopic MVP staging and white light endoscopic MES in assessing UC recurrence were statistically significant (p < 0.001). Spearman's correlation analysis showed a moderate correlation between NBI endoscopic MVP staging and clinical recurrence. NBI endoscopic MVP staging can predict HH and clinical recurrence status better than WLE.

Infliximab trough level combined with inflammatory biomarkers predict long-term endoscopic outcomes in Crohn’s disease under infliximab therapy

BACKGROUND

Infliximab trough level (ITL) severely affects therapeutic outcomes of Crohn’s disease (CD) patients under infliximab (IFX). Recently, frontier research has focused on identifying ITL based on different therapeutic targets. Although previous studies have elaborated clinical value of ITL monitoring on short-term outcomes in CD patients during therapy, studies contraposing the predictive value of ITL on long-term endoscopic outcomes in CD patients are still scarce domestically and overseas.

AIM

To explore the predictive value of ITL in combination with inflammatory biomarkers on long-term endoscopic outcomes in CD with clinical remission during IFX maintenance therapy.

METHODS

CD patients with endoscopic remission under long-term IFX maintenance therapy in the First Affiliated Hospital of Zhejiang Chinese Medicine University from January 2012 to December 2020 were collected. ITL and inflammatory biomarkers were continuously monitored during the therapy. The Step I study was conducted from weeks 14 to 54 of IFX treatment. The Step II study was conducted from weeks 54 to 108 of IFX treatment. Endoscopic outcomes were defined as endoscopic activity (Crohn’s disease endoscopic index of severity score > 2 points or Rutgeerts score > i1) and endoscopic remission (Crohn’s disease endoscopic index of severity score ≤ 2 points or Rutgeerts ≤ i1). Endoscopic relapse free survival was defined as endoscopic remission at the beginning of the study stage and maintaining endoscopic remission during the study stage.

RESULTS

At week 14, low ITL [odds ratio (OR) = 0.666, 95% confidence interval (CI): 0.514-0.862, P < 0.01] and high fecal calprotectin (FCP) level (OR = 1.002, 95%CI: 1.001-1.004, P < 0.01) increased the risk of endoscopic activity at week 54. At week 54, low ITL (OR = 0.466, 95%CI: 0.247-0.877, P < 0.01) and high C-reactive protein (CRP) level (OR = 1.590, 95%CI: 1.007-2.510, P < 0.01) increased the risk of endoscopic activity at week 108. At week 14, ITL ≤ 5.60 μg/mL [area under the curve (AUC) = 0.83, 95%CI: 0.73-0.90, P < 0.001] and FCP > 238 μg/g (AUC = 0.82, 95%CI: 0.72-0.89, P < 0.001) moderately predicted endoscopic activity at week 54. ITL ≤ 5.60 μg/mL in combination with FCP > 238 μg/g indicated 82.0% possibility of endoscopic activity. At week 54, ITL ≤ 2.10 μg/mL (AUC = 0.85, 95%CI: 0.72-0.93, P < 0.001) and CRP > 3.00 mg/L (AUC = 0.73, 95%CI: 0.60-0.84, P = 0.012) moderately predicted moderate endoscopic activity at week 108. ITL ≤ 2.10 μg/mL in combination with CRP > 3.00 mg/L indicated 100.0% possibility of endoscopic activity. From weeks 14 to 54 of IFX treatment, patients with ITL > 5.60 μg/mL had higher rate of endoscopic relapse free survival than those with ITL ≤ 5.60 μg/mL (95.83% vs 46.67%). From weeks 54 to 108 of IFX treatment, patients with ITL > 2.10 μg/mL had higher rate of endoscopic survival free relapsed rate than those with ITL ≤ 2.10 μg/mL (92.68% vs 30.77%).

CONCLUSION

Combination of ITL, CRP, and FCP contribute to long-term endoscopic prognosis monitoring. During IFX maintenance treatment, low ITL, high CRP level, and high FCP level were independent risk factors of CD patients with clinical remission in adverse endoscopy outcomes within 1-year follow-up.

Prevalence and factors associated with fatigue in patients with ulcerative colitis in China: a cross-sectional study

BACKGROUND

Fatigue is one of the most common symptoms reported by patients with ulcerative colitis (UC), while it has not been fully recognized and taken seriously in clinical practice. We aimed to investigate the prevalence of fatigue in patients with UC and identify the factors associated with fatigue and its severity in China.

METHODS

A cross-sectional study was conducted in Affiliated Hospital of Nanjing University of Chinese Medicine from May 2020 to February 2021. Demographic and clinical characteristics were collected. Fatigue was evaluated with the Fatigue Severity Scale and the Multidimensional Fatigue Inventory. The Hospital Anxiety and Depression Scale, the Pittsburgh Sleep Index Scale and the Malnutrition Universal Screening Tool were respectively used to evaluate the anxiety, depression, sleep disturbance and nutritional risk of patients with UC.

RESULTS

A total of 220 UC patients were enrolled in this study. The prevalence of fatigue in patients was 61.8%, of which in patients with disease activity was 68.2%, and in patients in remission was 40.0%. Univariate analysis indicated that the Montreal classification, disease activity, anemia, anxiety, depression, sleep disturbance and high nutritional risk were the factors associated with fatigue in Patients with UC. Multivariate logistic regression analysis showed that the Montreal classification (E3: E1, OR = 2.665, 95% CI = 1.134-6.216), disease activity (OR = 2.157, 95% CI = 1.055-4.410) and anxiety (OR = 2.867, 95% CI = 1.154-7.126) were related to an increased risk of fatigue. Disease activity (RC = 0.240, 95% CI = 0.193-0.674) and anxiety (RC = 0.181, 95% CI = 0.000-0.151) were associated with severity of fatigue.

CONCLUSIONS

This study demonstrated that the prevalence of fatigue among UC patients in China. The Montreal classification, disease activity and anxiety are associated with an increased risk of fatigue.

Combination of serological biomarkers and clinical features to predict mucosal healing in Crohn's disease: a multicenter cohort study

PURPOSE

Mucosal healing (MH) has become the treatment goal of patients with Crohn's disease (CD). This study aims to develop a noninvasive and reliable clinical tool for individual evaluation of mucosal healing in patients with Crohn's disease.

METHODS

A multicenter retrospective cohort was established. Clinical and serological variables were collected. Separate risk factors were incorporated into a binary logistic regression model. A primary model and a simple model were established, respectively. The model performance was evaluated with C-index, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy. Internal validation was performed in patients with small intestinal lesions.

RESULTS

A total of 348 consecutive patients diagnosed with CD who underwent endoscopic examination and review after treatment from January 2010 to June 2021 were composed in the derivation cohort, and 112 patients with small intestinal lesions were included in the validation cohort. The following variables were independently associated with the MH and were subsequently included into the primary prediction model: PLR (platelet to lymphocyte ratio), CAR (C-reactive protein to albumin ratio), ESR (erythrocyte sedimentation rate), HBI (Harvey-Bradshaw Index) score and infliximab treatment. The simple model only included factors of PLR, CAR and ESR. The primary model performed better than the simple one in C-index (87.5% vs. 83.0%, p = 0.004). There was no statistical significance between these two models in sensitivity (70.43% vs. 62.61%, p = 0.467), specificity (87.12% vs. 80.69%, p = 0.448), PPV (72.97% vs. 61.54%, p = 0.292), NPV (85.65% vs. 81.39%, p = 0.614), and accuracy (81.61% vs. 74.71%, p = 0.303). The primary model had good calibration and high levels of explained variation and discrimination in validation cohort.

CONCLUSIONS

This model can be used to predict MH in post-treatment patients with CD. It can also be used as an indication of endoscopic surveillance to evaluate mucosal healing in patients with CD after treatment.

Histological Disease Activity Measured by the Nancy Index Is Associated with Long-term Outcomes in Patients with Ulcerative Colitis

BACKGROUND AND AIMS

Histological healing might be the ultimate therapeutic goal in ulcerative colitis [UC]. Our aim was to investigate the association between histological disease activity as measured by a validated index and long-term outcomes in patients with UC.

METHODS

An observational retrospective cohort study was conducted at the Nancy University Hospital between January 2014 and March 2020. All consecutive patients with confirmed UC, undergoing colonoscopy with biopsies and available histological reports, were eligible for inclusion.

RESULTS

A total of 156 patients were included [53% female with a mean age of 41.3 ± 15.4 years]. About a quarter of patients were in histological remission [Nancy index = 0] at baseline [n = 42, 26.9%]. Median follow-up was 30.5 months [range 0-75]. Sixteen patients with histological disease activity at baseline [Nancy index ≥ 1] underwent surgery during follow-up compared with no subject in the histological remission group [14.0% vs 0.0%, respectively, p = 0.01]. Similarly, a higher rate of hospitalisation was found in patients with histological disease activity at baseline than in the histological remission group [36.0% vs 7.1%, respectively, p = 0.001]. The Kaplan-Meier analysis showed that patients with histological disease activity at baseline had a 5-year surgery rate of 16.7% [logrank p = 0.01] and a 5-year hospitalisation rate of 19.7% [logrank p = 0.0002]. In the multivariate regression model, Nancy index > 0 was independently associated with the risk of hospitalisation [hazard ratio 8.88, confidence interval 95% 2.5-31.1, p = 0.0007].

CONCLUSIONS

UC patients with histological disease activity, as measured by the Nancy index, have a greater risk of surgery and hospitalisation.

Drug Targeting of Inflammatory Bowel Diseases by Biomolecules

Inflammatory bowel disease (IBD) is a group of disabling, destructive and incurable immune-mediated inflammatory diseases comprising Crohn’s disease (CD) and ulcerative colitis (UC), disorders that are highly prevalent worldwide and demand a large investment in healthcare. A persistent inflammatory state enables the dysfunction and destruction of healthy tissue, hindering the initiation and endurance of wound healing. Current treatments are ineffective at counteracting disease progression. Further, increased risk of serious side effects, other comorbidities and/or opportunistic infections highlight the need for effective treatment options. Gut microbiota, the key to preserving a healthy state, may, alternatively, increase a patient’s susceptibility to IBD onset and development given a relevant bacterial dysbiosis. Hence, the main goal of this review is to showcase the main conventional and emerging therapies for IBD, including microbiota-inspired untargeted and targeted approaches (such as phage therapy) to infection control. Special recognition is given to existing targeted strategies with biologics (via monoclonal antibodies, small molecules and nucleic acids) and stimuli-responsive (pH-, enzyme- and reactive oxygen species-triggered release), polymer-based nanomedicine that is specifically directed towards the regulation of inflammation overload (with some nanosystems additionally functionalized with carbohydrates or peptides directed towards M1-macrophages). The overall goal is to restore gut balance and decrease IBD’s societal impact.

Relevance of monitoring transmural disease activity in patients with Crohn's disease: current status and future perspectives

Treatment targets of inflammatory bowel diseases (IBD), ulcerative colitis (UC) and Crohn's disease (CD) have evolved over the last decade. Goals of therapy consisting of symptom control and steroid sparing have shifted to control of disease activity with endoscopic remission being an important endpoint. Unfortunately, this requires ileocolonoscopy, an invasive procedure. Biomarkers [C-reactive protein (CRP) and fecal calprotectin (FCP)] have emerged as surrogates for endoscopic remission and disease activity, but also have limitations. Despite this evolution, we must not lose sight that CD involves transmural inflammation, not fully appreciated with ileocolonoscopy. Therefore, transmural assessment of disease activity by cross-sectional imaging, in particular with magnetic resonance enterography (MRE) and intestinal ultrasonography (IUS), is vital to fully understand disease control. Bowel-wall thickness (BWT) is the cornerstone in assessment of transmural inflammation and BWT normalization, with or without bloodflow normalization, the key element demonstrating resolution of transmural inflammation, namely transmural healing (TH) or transmural remission (TR). In small studies, achievement of TR has been associated with improved long-term clinical outcomes, including reduced hospitalization, surgery, escalation of treatment, and a decrease in clinical relapse over endoscopic remission alone. This review will focus on the existing literature investigating the concept of TR or residual transmural disease and its relation to other existing treatment targets. Current data suggest that TR may be the next logical step in the evolution of treatment targets.