A review of the therapeutic management of Crohn's disease

Fecal microbiota is associated with extraintestinal manifestations in inflammatory bowel disease

INTRODUCTION

A large proportion of patients with inflammatory bowel disease (IBD) experience IBD-related inflammatory conditions outside of the gastrointestinal tract, termed extraintestinal manifestations (EIMs) which further decreases quality of life and, in extreme cases, can be life threatening. The pathogenesis of EIMs remains unknown, and although gut microbiota alterations are a well-known characteristic of patients with IBD, its relationship with EIMs remains sparsely investigated. This study aimed to compare the gut microbiota of patients with IBD with and without EIMs.

METHODS

A total of 131 Danish patients with IBD were included in the study, of whom 86 had a history of EIMs (IBD-EIM) and 45 did not (IBD-C). Stool samples underwent 16S rRNA sequencing. Amplicon sequence variants (ASVs) were mapped to the Silva database. Diversity indices and distance matrices were compared between IBD-EIM and IBD-C. Differentially abundant ASVs were identified using a custom multiple model statistical analysis approach, and modules of co-associated bacteria were identified using sparse correlations for compositional data (SparCC) and related to patient EIM status.

RESULTS

Patients with IBD and EIMs exhibited increased disease activity, body mass index, increased fecal calprotectin levels and circulating monocytes and neutrophils. Microbiologically, IBD-EIM exhibited lower fecal microbial diversity than IBD-C (Mann-Whitney's test, p = .01) and distinct fecal microbiota composition (permutational multivariate analysis of variance; weighted UniFrac, R2 = 0.018, p = .01). A total of 26 ASVs exhibited differential relative abundances between IBD-EIM and IBD-C, including decreased Agathobacter and Blautia and increased Eggerthella lenta in the IBD-EIM group. SparCC analysis identified 27 bacterial co-association modules, three of which were negatively related to EIM (logistic regression, p < .05) and included important health-associated bacteria, such as Agathobacter and Faecalibacterium.

CONCLUSIONS

The fecal microbiota in IBD patients with EIMs is distinct from that in IBD patients without EIM and could be important for EIM pathogenesis.

How comparative studies can inform treatment decisions for Crohn's disease

INTRODUCTION

As new therapies for the treatment of Crohn's disease (CD) are approved, there is an increasing need for evidence that clarifies their positioning and sequencing.

AREAS COVERED

Comparative effectiveness research (CER) aims to inform physicians' decisions when they choose which intervention (drug or treatment strategy) to administer to their patients. Pragmatic head-to-head trials represent the best tools for CER, but only a few have been published in the IBD field. Network meta-analyses can point toward the superiority of one drug over another, but they do not reflect everyday clinical practice. Finally, real-world evidence complements that coming from head-to-head trials and network meta-analyses, assessing the real-life effectiveness of therapeutic interventions.

EXPERT OPINION

There is insufficient evidence to create a definitive therapeutic algorithm for CD, but some general considerations can be made. Anti-TNF-α agents seemingly represent the most 'sustainable' first-line choice, considering benefit-harm ratio and costs; vedolizumab, ustekinumab, and risankizumab may be considered as first-line choice when safety issues become prominent. In the event of pharmacodynamic failure, out-of-class swap is to be preferred - possibly with anti-IL23p19 as the best option, with unclear data regarding upadacitinib positioning; a second anti-TNF-α could be considered, as a second choice, after pharmacokinetic failure.

Baseline Characteristics of Adult Patients Treated and Never Treated with Teduglutide in a Multinational Short Bowel Syndrome and Intestinal Failure Registry

The Short Bowel Syndrome (SBS) Registry (NCT01990040) is a multinational real-world study evaluating the long-term safety of teduglutide in patients with SBS and intestinal failure (SBS-IF) in routine clinical practice. This paper describes the study methodology and baseline characteristics of adult patients who have (ever-treated) or have never (never-treated) received teduglutide. A total of 1411 adult patients (679 ever-treated; 732 never-treated) were enrolled at 124 sites across 17 countries. The mean (standard deviation [SD]) age at enrollment was 55.4 (15.46) years, and 60.2% of patients were women. Crohn's disease was the most common cause of major intestinal resection in both ever-treated (34.1%) and never-treated patients (20.4%). A similar proportion of ever-treated and never-treated patients had a prior history of colorectal polyps (2.7% vs. 3.6%), whereas proportionally fewer ever-treated patients reported a history of colorectal cancer (1.8% vs. 6.2%) or any malignancy (17.7% vs. 30.0%) than never-treated patients. Never-treated patients received a numerically greater mean (SD) volume of parenteral nutrition and/or intravenous fluids than ever-treated patients (12.4 [8.02] vs. 10.1 [6.64] L/week). Ever-treated patients received a mean teduglutide dosage of 0.05 mg/kg/day. This is the first report of patient baseline characteristics from the SBS Registry, and the largest cohort of patients with SBS-IF to date. Overall, ever-treated and never-treated patients had similar baseline characteristics. Differences between treatment groups may reflect variations in patient selection and degree of monitoring.

Allosterically activating SHP2 by oleanolic acid inhibits STAT3-Th17 axis for ameliorating colitis

Src homology 2 domain-containing tyrosine phosphatase 2 (SHP2) is an essential tyrosine phosphatase that is pivotal in regulating various cellular signaling pathways such as cell growth, differentiation, and survival. The activation of SHP2 has been shown to have a therapeutic effect in colitis and Parkinson's disease. Thus, the identification of SHP2 activators and a complete understanding of their mechanism is required. We used a two-step screening assay to determine a novel allosteric activator of SHP2 that stabilizes it in an open conformation. Oleanolic acid was identified as a suitable candidate. By binding to R362, K364, and K366 in the active center of the PTP domain, oleanolic acid maintained the active open state of SHP2, which facilitated the binding between SHP2 and its substrate. This oleanolic acid-activated SHP2 hindered Th17 differentiation by disturbing the interaction between STAT3 and IL-6Rα and inhibiting the activation of STAT3. Furthermore, via the activation of SHP2 and subsequent attenuation of the STAT3-Th17 axis, oleanolic acid effectively mitigated colitis in mice. This protective effect was abrogated by SHP2 knockout or administration of the SHP2 inhibitor SHP099. These findings underscore the potential of oleanolic acid as a promising therapeutic agent for treating inflammatory bowel diseases.

Advancements in Targeted Therapies for the Management of Crohn's Disease: A Comprehensive Review

Crohn's disease (CD) is a complex clinical condition characterized by persistent gastrointestinal inflammation that leads to episodes of flare-ups and subsequent healing. The treatment options for this disease are heterogeneous as its impact on different patients is also different. This study aims to evaluate the effectiveness of recently approved drugs that specifically target certain pathways within cells that are involved in CD pathogenesis. These medicines include biologics like anti-TNF agents, interleukin inhibitors, and small molecule inhibitors; they work by altering the modulation of immune responses and reducing inflammation. These drugs seem promising in terms of inducing remission in moderate to severe CD among various patient populations. Conversely, it is possible to examine how well these drugs perform using gene expression and molecular markers. By understanding these results along with other ongoing trials, personalized medicine can be used more frequently by doctors who will adopt a strategy for an individual patient, maximizing benefits while minimizing adverse effects. There are still some issues that need to be worked out like the high cost associated with these drugs or immunogenicity risk and infectious complications too. In conclusion, there has been a remarkable improvement in CD management over the past decade with customized drugs leading toward a precision medical era. Further understanding of molecular mechanisms implicated in CD pathogenesis and new therapeutic approaches could potentially improve treatment outcomes among affected individuals. This research is crucial in understanding how CD therapeutics are changing, thus facilitating selection by doctors on the most appropriate methods for individualized patient care.

Refractory Crohn's Disease Responsive to Dietary Therapy: A Case Report

Crohn's disease is a type of inflammatory bowel disease (IBD) that typically presents in the second or third decade of life. There are various pharmaceutical therapies that have been developed to treat the disease's symptoms. However, some patients still do not find relief with these medications and turn to other therapies such as diet modification. The underlying cause of Crohn's disease involves multiple factors such as uncontrolled inflammation and several genetic variants. While most current medication therapies control the symptoms that occur due to this uncontrolled level of inflammation, an anti-inflammatory diet (AID) may actually lower the level of inflammation in the gut and therefore reduce the amount of disease symptoms in Crohn's disease. Some such diets include the IBD-AID, Crohn's disease exclusion diet, and the Groningen AID (GrAID). This report describes a case of treatment-resistant Crohn's disease in a patient who was given all categories of pharmaceutical therapies including prednisone, budesonide, sulfasalazine, olsalazine, 6-mercaptopurine, methotrexate, mesalamine, and adalimumab. These only gave temporary relief of symptoms and eventually failed for various reasons including allergic reaction, insufficient symptom control, and antibody formation against the medication. This prompted the patient to independently research AIDs instead. In conclusion, for patients whose disease is refractory to different treatments, or who develop antibodies to the medication, AIDs may offer a solution to reduce disease symptoms and progression. Education of healthcare professionals and patients alike is vital in order for Crohn's patients to gain the benefits from dietary therapy.

Racial and Ethnic Disparities in Health-Related Outcomes in Crohn's Disease: Results From the National Health and Wellness Survey

Background

Crohn's disease (CD) is a chronic inflammatory condition affecting the entire gastrointestinal tract that is associated with significant humanistic, clinical, and economic burdens. Few studies have assessed the association between CD severity and patient-reported outcomes (PROs), healthcare resource utilization (HCRU), and medical costs; even fewer have examined differences in disease outcomes among patients of various racial/ethnic groups.

Methods

In this cross-sectional study, sociodemographic data, PROs, and economic outcomes for participants with self-reported CD were collected from the National Health and Wellness Survey (2018-2020). Multivariable analyses were used to assess the association of CD severity and race/ethnicity with health-related quality of life (HRQoL), work productivity and activity impairment (WPAI), HCRU, and medical costs.

Results

Analyses included 1077 participants with CD (818 non-Hispanic White, 109 non-Hispanic Black, and 150 Hispanic). Participants with self-reported moderate/severe CD reported significantly worse HRQoL and WPAI, greater HCRU, and higher medical costs than those with self-reported mild CD. Non-Hispanic Black participants reported better HRQoL and fewer healthcare provider visits than non-Hispanic White participants. There were no significant differences in PROs between non-Hispanic White and Hispanic groups. Interactions between race/ethnicity and CD severity emerged for some, but not all groups: Specifically, non-Hispanic Black participants with moderate/severe CD reported greater absenteeism and more gastroenterologist visits than non-Hispanic Black participants with mild CD.

Conclusions

Participants with moderate/severe CD reported worse PROs, greater HCRU, and higher medical costs than those with mild CD. Additionally, racial/ethnic differences were found across several HCRU and economic outcomes. Further research is needed to better understand factors contributing to burden among patients with varying CD severity across racial/ethnic groups.

Effectiveness and safety of vedolizumab and infliximab in biologic-naive patients with Crohn's disease: results from the EVOLVE study

OBJECTIVES

This study compared the real-world effectiveness and safety of α 4 β 7 -integrin inhibitor vedolizumab and anti-tumor necrosis factor alpha (anti-TNFα) inhibitor infliximab in biologic-naive patients with Crohn's disease (CD).

METHODS

EVOLVE was a retrospective, multicenter, medical chart review of biologic-naive adults with inflammatory bowel disease receiving vedolizumab or anti-TNFα treatment as first-line biologics in Canada, Greece, and the USA. Twelve-month outcomes were analyzed in vedolizumab- or infliximab-treated patients with moderate-to-severe CD (and subgroups with complicated and noncomplicated CD) including cumulative rates of clinical response, clinical remission, and mucosal healing, and incidence rates of serious adverse events (SAEs) and serious infections (SIs). Inverse probability weighting (IPW) was used to account for baseline differences between treatment groups.

RESULTS

Data were analyzed from 167 patients. In the IPW dataset (99 vedolizumab-treated and 63 infliximab-treated), adjusted 12-month clinical remission rates were 73.1% and 55.2%, respectively ( P  = 0.31). Overall, effectiveness rates were similar across treatment and complicated/noncomplicated disease subgroups. Adjusted 12-month incidence rates (first occurrence/1000 person-years) of SAEs for vedolizumab vs. infliximab: 43.6 vs. 200.9 [hazard ratio (HR) 0.36 (0.09-1.54)]; SIs: 10.8 vs. 96.0 [HR 0.08 (<0.01-2.64)]. AE incidence was significantly lower in vedolizumab- vs. infliximab-treated patients for complicated [131.6 vs. 732.2; HR 0.19 (0.05-0.65)] and noncomplicated [276.3 vs. 494.8; HR 0.59 (0.35-0.99)] disease subgroups.

CONCLUSION

These real-world data on first-line biologics show no differences in 12-month effectiveness outcomes for vedolizumab- vs. infliximab-treated biologic-naive patients with CD. Vedolizumab may have a more favorable safety profile vs. infliximab in patients with complicated and noncomplicated disease.

Intestinal Ultrasound and MRI for Monitoring Therapeutic Response in Luminal Crohn's Disease: A Systematic Review

PURPOSE

Cross-sectional imaging facilitates the assessment of transmural healing in patients with Crohn's disease. This systematic review addresses the utility of MRI and intestinal ultrasound (IUS) in the assessment of disease activity in response to drug therapy compared with endoscopy in patients with luminal Crohn's disease.

METHODS

Database searches were undertaken using predefined terms. Studies with ≥10 patients with luminal Crohn's disease with paired endoscopy and imaging (MRI or IUS) after treatment initiation were included. Publications were identified through searches of six bibliographic databases, all run on June 24, 2022. Records were screened on title and abstract, then full text, by two independent reviewers.

RESULTS

In total, 5,760 records were identified, with 24 studies meeting the inclusion criteria. Ten studies examined IUS and found good correlation between IUS and endoscopic remission (κ = 0.63-0.73). Early reduction in bowel wall thickness at 4 to 8 weeks predicted endoscopic response at 12 to 38 weeks (area under the receiver operating characteristic curve [AUROC], 0.77; odds ratio, 10.8; P = .01). Twelve studies examined MRI, with the Magnetic Resonance Index of Activity score having high accuracy for predicting endoscopic remission (AUROC, 0.97; sensitivity, 93%; specificity, 77%). A Simplified Magnetic Resonance Index of Activity score cutoff of ≥1 identifies active endoscopic disease (AUROC, 0.92; 95% confidence interval, 0.88-0.95; P < .0001).

CONCLUSIONS

IUS and MRI are both reliable, noninvasive modalities for assessing transmural healing in patients with Crohn's disease and are accurate in monitoring the response to drug therapy. These modalities can be used to monitor response to biologic induction therapy, with early changes predictive of response to treatment.

The effect of anti-TNF drugs on the intestinal microbiota in patients with spondyloarthritis, rheumatoid arthritis, and inflammatory bowel diseases

Spondyloarthritis (SpA), rheumatoid arthritis (RA), and inflammatory bowel diseases (IBD) are chronic inflammatory autoimmune diseases that are associated with alterations in the composition of the intestinal microbiota (i.e., dysbiosis). For SpA and RA, a gut-joint-enthesis axis is hypothesized and recent data suggests that dysbiosis may contribute directly to initiating and perpetuating joint and spine inflammation. Biologic drugs targeting tumor necrosis factor (TNF) are effective in treating these diseases and have been shown to partially restore the disrupted microbiome. Hence, drugs that affect both the intestinal and joint components of these diseases, such as anti-TNF drugs, may act on the intestinal microbiome. However, despite the remarkable efficacy of anti-TNF-α treatments, non-responders are frequent, and predictors of patient outcomes have not been identified. In this narrative review, we summarize recent research on the downstream effects of anti-TNF drugs on the intestinal microbiota in SpA, RA, and IBD. We also discuss whether these changes could have a role as predictive biomarkers of anti-TNF response.

Utility of panenteric capsule endoscopy for the detection of small-bowel Crohn's disease in patients with a normal magnetic resonance enterography: A prospective observational pilot study

Background and Aim

Capsule endoscopy allows the direct visualization of the small bowel. We examined the diagnostic utility of a new modality, namely panenteric Crohn's capsule endoscopy (CE), in detecting active small-bowel Crohn's disease (CD) in those with normal magnetic resonance enterography (MRE).

Methods

We prospectively recruited patients with a diagnosis of CD or suspected small-bowel CD in whom the MRE was normal. Inclusion criteria included abdominal symptoms and abnormal serum or fecal biomarkers. The primary outcome was the detection of active small-bowel CD (measured through the Lewis score [LS]). Secondary outcomes included change in Montreal classification for those with a pre-existing CD diagnosis, change in medical therapy, clinical activity, and biomarkers at baseline and 6 months, and quality-of-life measures.

Results

A total of 22 patients with a diagnosis of CD or suspected new diagnosis were recruited, with CE complete to the caecum in 21 and 18/21 (86%) showing evidence of active small-bowel CD (LS > 135). Of the patients with a pre-existing diagnosis of CD, 9/11 (82%) had a change in Montreal classification. At 6 months following CE, 17/18 (94%) had clinician-directed change in therapy. This correlated with an improvement in the quality of life (P < 0.05 as per the Short Inflammatory Bowel Disease Questionnaire), a reduction in the Harvey Bradshaw index (median: 7-4, P < 0.001), and favorable CRP and albumin response.

Conclusion

Crohn's CE is a useful diagnostic test for assessing active small-bowel CD when imaging is normal but clinical suspicion is high. Crohn's CE should be integrated into the diagnostic algorithm for small-bowel CD.

Crohn's disease: an update

Crohn's disease (CD) is a chronic, relapsing and remitting inflammatory bowel disease (IBD) that is increasing in incidence and prevalence globally. Management aims to achieve endoscopic healing, symptom resolution and improvement in quality of life. Therapeutic approaches in CD vary depending on disease phenotype. Thiopurines are important in steroid-sparing maintenance therapy, while anti-tumour necrosis factor agents play a fundamental role, especially in fistulising CD. Suboptimal response to these medications may require escalation to other immunosuppressive and biologic therapies, and surgical intervention is still required in a proportion of patients. Tailoring treatment to target specific patient phenotypes, disease severity and patient wishes is becoming more feasible with the growing array of therapeutic options in CD.

Characterization of prokineticin system in Crohn's disease pathophysiology and pain, and its modulation by alcohol abuse: A preclinical study

BACKGROUND

Crohn's disease-(CD) pathogenesis is still unknown and chronic pain is a frequent symptom in CD-patients. Identifying novel therapeutic targets and predisposing factors is a primary goal. In this regard, prokineticin system-(PKS) appears a promising target.

AIMS AND METHODS

TNBS-model was used. DAI, abdominal and visceral pain, and muscle strength were monitored. CD-mice were sacrificed at two times (day 7 and 14 after TNBS) in order to identify PKS involvement in CD pathophysiology and pain. PKS characterization was performed in mesenteric lymph nodes-(MLN), colon, myenteric plexus-(MP), dorsal root ganglia-(DRGs) and spinal cord-(SC). Inflammation/neuroinflammation was also assessed in the same tissues. In order to evaluate alcohol abuse as a possible trigger for CD and its effect on PKS activation, naïve mice were administered (oral-gavage) with ethanol for 10 consecutive days. PKS as well as inflammation/neuroinflammation were evaluated in MLN, colon and MP.

RESULTS

TNBS treated-mice showed a rapid increase in DAI, abdominal/visceral hypersensitivity and a progressive strength loss. In all tissue analysed of CD-mice, a quick and significant increase of mRNA of PKs and PKRs was observed, associated with an increase of pro-inflammatory cytokines (IL-1β, IL-6 and TNFα) and macrophage/glia markers (iba1, CD11b and GFAP) levels. In alcohol abuse model, ethanol induced in colon and MP a significant PKS activation accompanied by inflammation/neuroinflammation.

CONCLUSIONS

We can assume that PKS may be involved in CD development and pain. Furthermore, alcohol appears to activate PKS and may be a trigger factor for CD.

The Utility of Faecal Calprotectin, Lactoferrin and Other Faecal Biomarkers in Discriminating Endoscopic Activity in Crohn's Disease: A Systematic Review and Meta-Analysis

INTRODUCTION

Currently, faecal calprotectin (FC) is the predominate faecal biomarker utilised in clinical practice to monitor Crohn's disease (CD) activity. However, there are several potential faecal biomarkers described in the literature. We performed a meta-analysis to determine the accuracy of faecal biomarkers in discriminating endoscopic activity and mucosal healing in CD.

METHODS

We searched the medical literature using MEDLINE, EMBASE, and PubMed from 1978 to 8 August 2022. Descriptive statistics, including sensitivity, specificity of the primary studies, their positive and negative likelihood ratios, and their diagnostic odds ratio (DOR), were calculated. The methodological quality of the included studies was evaluated using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS) criteria.

RESULTS

The search found 2382 studies, of which 33 were included for analysis after screening. FC was found to have a pooled sensitivity and specificity, DOR, and negative predictive value (NPV) in discriminating active endoscopic disease (versus inactive) of 81%, 74%, 13.93, and 0.27, respectively. Faecal lactoferrin (FL) had a pooled sensitivity and specificity, DOR, and NPV in discriminating active endoscopic disease of 75%, 80%, 13.41, and 0.34, respectively. FC demonstrated a pooled sensitivity and specificity, DOR, and NPV of 88%, 72%, 18.17, and 0.19 in predicting mucosal healing.

CONCLUSION

FC remains an accurate faecal biomarker. Further evaluation of the utility of novel faecal biomarkers is needed.

Expression and function of α4β7 integrin predict the success of vedolizumab treatment in inflammatory bowel disease

Inflammatory bowel diseases are medically intractable and require constant therapy in many cases. While a growing number of biologicals and small molecules is available for treatment, a substantial portion of patients experiences primary non-response to these compounds and head-to-head evidence for therapy selection is scarce. Thus, approaches to predict treatment success in individual patients are a huge unmet need. We had previously suggested that the expression and function of α4β7 integrin on T cells in the peripheral blood correlate to outcomes of therapy with the anti-α4β7 integrin antibody vedolizumab. Here, we conducted a translational multicenter trial to prospectively evaluate this hypothesis. In a cohort of 89 patients with inflammatory bowel disease undergoing regular therapy with vedolizumab, lower baseline expression of α4β7 was associated with short-term clinical response. Consistently, low α4β7 expression in patients achieving remission predicted sustained remission in week 30. Moreover, high dynamic adhesion of CD4⁺ T cells to MAdCAM-1 and high reduction of adhesion by vedolizumab in vitro at baseline were associated with clinical remission. These data substantiate the potential of α4β7 integrin function and expression to forecast outcomes of vedolizumab therapy. Further translational efforts are necessary to improve the performance of the assays and to implement the concept in clinical practice.

Etrolizumab as induction and maintenance therapy in patients with moderately to severely active Crohn's disease (BERGAMOT): a randomised, placebo-controlled, double-blind, phase 3 trial

BACKGROUND

Etrolizumab is a gut-targeted anti-β7 monoclonal antibody targeting α4β7 and αEβ7 integrins. We aimed to compare the safety and efficacy of two doses of etrolizumab with placebo in patients with Crohn's disease.

METHODS

BERGAMOT was a randomised, placebo-controlled, double-blind, phase 3 study done at 326 treatment centres worldwide. We included patients aged 18-80 years with moderately to severely active Crohn's disease (Crohn's Disease Activity Index [CDAI] score of 220-480, and a mean daily stool frequency score of ≥6 or a mean daily stool frequency score of >3, and a mean daily abdominal pain score of >1, as well as the presence of active inflammation on screening ileocolonoscopy) who had intolerance, inadequate response, or no response to one or more of corticosteroids, immunosuppressants, or anti-TNF therapy within the past 5 years. BERGAMOT consisted of three induction cohorts (a placebo-controlled, double-blind exploratory cohort [cohort 1]; an active treatment cohort not containing a placebo control [cohort 2]; and a placebo-controlled, double-blind pivotal cohort [cohort 3]) and one maintenance cohort. In induction cohort 3, during the 14-week induction, patients were randomly assigned (2:3:3) to receive matched placebo, 105 mg etrolizumab subcutaneously every 4 weeks (at weeks 0, 4, 8, and 12) or 210 mg etrolizumab subcutaneously (at weeks 0, 2, 4, 8, and 12), stratified by concomitant treatment with oral corticosteroids, concomitant treatment with immunosuppressants, baseline disease activity, and previous exposure to anti-TNF therapy. To preserve masking, all patients received two injections at weeks 0, 4, 8, and 12 and one injection at week 2. Week 14 etrolizumab responders from all cohorts were re-randomly assigned (1:1) to receive 105 mg etrolizumab (etrolizumab maintenance group) or placebo (placebo maintenance group) every 4 weeks for 52 weeks; patients in the induction placebo group underwent a sham re-randomisation to preserve masking. During maintenance, randomisation was stratified by CDAI remission status, concomitant treatment with oral corticosteroids, induction dose regimen, and previous exposure to anti-TNF therapy. All participants and study site personnel were masked to treatment assignment for both induction and maintenance. Co-primary induction endpoints at week 14 (placebo vs 210 mg etrolizumab) were clinical remission (mean stool frequency ≤3 and mean abdominal pain ≤1, with no worsening) and endoscopic improvement (≥50% reduction in Simple Endoscopic Score for Crohn's Disease [SES-CD]). Co-primary maintenance endpoints at week 66 (placebo vs etrolizumab) were clinical remission and endoscopic improvement. Efficacy was analysed using a modified intention-to-treat (mITT) population, defined as all randomised patients who received at least one dose of study drug (induction) and as all patients re-randomised into maintenance who received at least one dose of study drug in the maintenance phase (maintenance). Safety analyses included all patients who received at least one dose of study drug. Maintenance safety analyses include all adverse events occurring in both induction and maintenance. This trial is registered with ClinicalTrials.gov, NCT02394028, and is closed to recruitment.

FINDINGS

Between March 20, 2015, and Sept 7, 2021, 385 patients (209 [54%] male and 326 [85%] white) were randomly assigned in induction cohort 3 to receive placebo (n=97), 105 mg etrolizumab (n=143), or 210 mg etrolizumab (n=145). 487 patients had a CDAI-70 response in any of the induction cohorts and were enrolled into the maintenance cohort, of whom 434 had a response to etrolizumab and were randomly assigned to placebo (n=217) or 105 mg etrolizumab (n=217). At week 14, 48 (33%) of 145 patients in the 210 mg induction etrolizumab group versus 28 (29%) of 96 patients in the placebo induction group were in clinical remission (adjusted treatment difference 3·8% [95% CI -8·3 to 15·3]; p=0·52), and 40 (27%) versus 21 (22%) showed endoscopic improvement (5·8% [-5·4 to 17·1]; p=0·32). At week 66, a significantly higher proportion of patients receiving etrolizumab than those receiving placebo had clinical remission (76 [35%] of 217 vs 52 [24%] of 217; adjusted treatment difference 11·3% [95% CI 2·7-19·7]; p=0·0088) and endoscopic improvement (51 [24%] vs 26 [12%]; 11·5% [4·1-18·8]; p=0·0026). Similar proportions of patients reported one or more adverse events during induction (95 [66%] of 143 in the 105 mg etrolizumab group, 85 [59%] of 145 in the 210 mg etrolizumab group, and 51 [53%] of 96 in the placebo group) and maintenance (189 [87%] of 217 in the etrolizumab group and 190 [88%] of 217 in the placebo group). During induction, the most common treatment-related adverse events were injection site erythema (six [4%] of 143 in the 105 mg etrolizumab group, four [3%] of 145 in the 210 mg etrolizumab group, and none of 96 in the placebo group), and arthralgia (two [1%], one [1%], and four [4%]). In the maintenance cohort, the most common treatment-related adverse events were injection site erythema (six [3%] of 217 in the etrolizumab group vs 14 [6%] of 217 in the placebo: group), arthralgia (five [2%] vs eight [4%]), and headache (five [2%] vs seven [3%]). The most common serious adverse event was exacerbation of Crohn's disease (14 [6%] of 217 patients taking placebo and four [2%] of 217 patients taking 105 mg etrolizumab in the maintenance cohort).

INTERPRETATION

A significantly higher proportion of patients with moderately to severely active Crohn's disease achieved clinical remission and endoscopic improvement with etrolizumab than placebo during maintenance, but not during induction.

FUNDING

F Hoffmann-La Roche.

Fueling the fire in the gut

Gut dysbiosis has long been associated with the development of Crohn's disease and other gastrointestinal disorders. Otake-Kasamoto et al. (2022. J. Exp. Med.https://doi.org/10.1084/jem.20211291) report that dysbiotic microbiota-derived bioactive lipids, lysophosphatidylserines, can promote pathological Th1 cell responses through inducing metabolic reprogramming and epigenetic changes.