Metabonomics and the Gut Microbiome Associated With Primary Response to Anti-TNF Therapy in Crohn's Disease

BACKGROUND AND AIMS

Anti-tumour necrosis factor [anti-TNF] therapy is indicated for treatment of moderate to severe inflammatory bowel disease [IBD], but has a primary non-response rate of around 30%. We aim to use metabonomic and metataxonomic profiling to identify predictive biomarkers of anti-TNF response in Crohn's disease.

METHODS

Patients with luminal Crohn's disease, commencing anti-TNF therapy, were recruited with urine, faeces, and serum samples being collected at baseline and 3-monthly. Primary response was defined according to a combination of clinical and objective markers of inflammation. Samples were measured using three UPLC-MS assays: lipid, bile acid, and Hydrophillic Interaction Liquid Chromatography [HILIC] profiling with 16S rRNA gene sequencing of faeces.

RESULTS

Samples were collected from 76 Crohn's disease patients who were anti-TNF naïve and from 13 healthy controls. There were 11 responders, 37 non-responders, and 28 partial responders in anti-TNF-treated Crohn's patients. Histidine and cysteine were identified as biomarkers of response from polar metabolite profiling [HILIC] of serum and urine. Lipid profiling of serum and faeces found phosphocholines, ceramides, sphingomyelins, and triglycerides, and bile acid profiling identified primary bile acids to be associated with non-response to anti-TNF therapy, with higher levels of phase 2 conjugates in non-responders. Receiver operating curves for treatment response demonstrated 0.94 +/ -0.10 [faecal lipid], 0.81 +/- 0.17 [faecal bile acid], and 0.74 +/- 0.15 [serum bile acid] predictive ability for anti-TNF response in Crohn's disease.

CONCLUSIONS

This prospective, longitudinal cohort study of metabonomic and 16S rRNA gene sequencing analysis demonstrates that a range of metabolic biomarkers involving lipid, bile acid, and amino acid pathways may contribute to prediction of response to anti-TNF therapy in Crohn's disease.

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Current Practices in Ileal Pouch Surveillance for Patients With Ulcerative Colitis: A Multinational, Retrospective Cohort Study

BACKGROUND AND AIMS

There are no universally accepted guidelines regarding surveillance of ulcerative colitis [UC] patients after restorative proctocolectomy and ileal pouch-anal anastomosis [IPAA]. There also exists a lack of validated quality assurance standards for performing pouchoscopy. To better understand IPAA surveillance practices in the face of this clinical equipoise, we carried out a retrospective cohort study at five inflammatory bowel disease [IBD] referral centres.

METHODS

Records of patients who underwent IPAA for UC or IBD unclassified [IBDU] were reviewed, and patients with <1-year follow-up after restoration of intestinal continuity were excluded. Criteria for determining the risk of pouch dysplasia formation were collected as well as the use of pouchoscopy, biopsies, and completeness of reports.

RESULTS

We included 272 patients. Median duration of pouch follow-up was 10.5 [3.3-23.6] years; 95/272 [35%] had never undergone pouchoscopy for any indication; 191/272 [70%] had never undergone pouchoscopy with surveillance as the specific indication; and 3/26 [12%] high-risk patients had never undergone pouchoscopy. Two cases of adenocarcinoma were identified, occurring in the rectal cuff of low-risk patients. Patients under the care of surgeons appeared more likely to undergo surveillance, but rates of incomplete reporting were higher among surgeons [78%] than gastroenterologists [54%, p = 0.002].

CONCLUSIONS

We observed wide variation in surveillance of UC/IBDU-IPAA patients. In addition, the rate of neoplasia formation among 'low-risk' patients was higher than may have been expected. We therefore concur with previous recommendations that pouchoscopy be performed at 1 year postoperatively, to refine risk-stratification based on clinical factors alone. Reports should document findings in all regions of the pouch and biopsies should be taken.

Long term outcomes of initial infliximab therapy for inflammatory pouch pathology: a multi-Centre retrospective study

BACKGROUND

Restorative proctocolectomy with ileal pouch-anal anastomosis is considered the procedure of choice in patients with ulcerative colitis refractory to medical therapy. Subsequent inflammation of the pouch is a common complication and in some cases, pouchitis fails to respond to antibiotics, the mainstay of treatment. In such cases, corticosteroids, immunomodulatory or biologic treatments are options. However, our understanding of the efficacy of anti-tumour necrosis factor medications in both chronic pouchitis and Crohn's-like inflammation is based on studies that include relatively small numbers of patients.

METHODS

This was an observational, retrospective, multi-centre study to assess the long-term effectiveness and safety of infliximab (IFX) for inflammatory disorders related to the ileoanal pouch. The primary outcome was the development of IFX failure defined by early failure to IFX or secondary loss of response to IFX.

RESULTS

Thirty-four patients met the inclusion criteria; 18/34 (53%) who were initiated on IFX for inflammatory disorders of the pouch had IFX failure, 3/34 (8%) had early failure and 15/34 (44%) had secondary loss of response with a median follow-up of 280 days (range 3-47 months). In total, 24/34 (71%) avoided an ileostomy by switching to other medical therapies at a median follow-up of 366 days (1-130 months).

CONCLUSIONS

Initial IFX therapy for pouch inflammatory conditions is associated with IFX failure in just over half of all patients. Despite a high failure rate, an ileostomy can be avoided in almost three-quarters of patients at four years by using other medical therapies.

The body composition profile is associated with response to anti-TNF therapy in Crohn's disease and may offer an alternative dosing paradigm

BACKGROUND

Anti-tumour necrosis factor (TNF)s form a major part of therapy in Crohn's disease and have a primary nonresponse rate of 10%-30% and a secondary loss of response rate of 5% per year. Myopenia is prevalent in Crohn's disease and is measured using body composition analysis tools.

AIM

To test the hypothesis that body composition can predict outcomes of anti-TNF primary nonresponse and secondary loss of response.

METHODS

Between January 2007 and June 2012, 106 anti-TNF naïve patients underwent anti-TNF therapy for Crohn's disease with body composition parameters analysed using CT scans to estimate body fat-free mass. The outcome measures were primary nonresponse and secondary loss of response. COX-regression analysis was used with 3 year follow-up data.

RESULTS

A total of 106 patients were included for analysis with 26 (24.5%) primary nonresponders and 29 (27.4%) with secondary loss of response to anti-TNF therapy. Sex-specific cut-offs for muscle and fat were ascertained by stratification analysis. On univariate analysis, primary nonresponse was associated with low albumin (OR 0.94; 0.88-0.99, P = .04) and presence of myopenia (OR 4.69; 1.83-12.01, P = .001) when taking into account patient's medical therapy, severity of disease and body composition. On multivariate analysis, presence of myopenia was associated with primary nonresponse (OR 2.93; 1.28-6.71, P = .01). Immunomodulator therapy was associated with decreased secondary loss of response (OR 0.48; 0.23-0.98, P = .04). BMI was poorly correlated with lean body mass (r² = 0.15, P = .54).

CONCLUSIONS

In this cohort study, body composition profiles did not correlate well with BMI. Myopenia was associated with primary nonresponse with potential implications for dosing and serves as an explanation for pharmacokinetic failure.