Clinical and biological predictors of response to standardised paediatric colitis therapy (PROTECT): a multicentre inception cohort study.

BACKGROUND: Lack of evidence-based outcomes data leads to uncertainty in developing treatment regimens in children who are newly diagnosed with ulcerative colitis. We hypothesised that pretreatment clinical, transcriptomic, and microbial factors predict disease course. METHODS: In this inception cohort study, we recruited paediatric patients aged 4-17 years with newly diagnosed ulcerative colitis from 29 centres in the USA and Canada. Patients initially received standardised mesalazine or corticosteroids, with pre-established criteria for escalation to immunomodulators (ie, thiopurines) or anti-tumor necrosis factor-α (TNFα) therapy. We used RNA sequencing to define rectal gene expression before treatment, and 16S sequencing to characterise rectal and faecal microbiota. The primary outcome was week 52 corticosteroid-free remission with no therapy beyond mesalazine. We assessed factors associated with the primary outcome using logistic regression models of the per-protocol population. This study is registered with ClinicalTrials.gov, number NCT01536535. FINDINGS: Between July 10, 2012, and April 21, 2015, of 467 patients recruited, 428 started medical therapy, of whom 400 (93%) were evaluable at 52 weeks and 386 (90%) completed the study period with no protocol violations. 150 (38%) of 400 participants achieved week 52 corticosteroid-free remission, of whom 147 (98%) were taking mesalazine and three (2%) were taking no medication. 74 (19%) of 400 were escalated to immunomodulators alone, 123 (31%) anti-TNFα therapy, and 25 (6%) colectomy. Low baseline clinical severity, high baseline haemoglobin, and week 4 clinical remission were associated with achieving week 52 corticosteroid-free remission (n=386, logistic model area under the curve [AUC] 0·70, 95% CI 0·65-0·75; specificity 77%, 95% CI 71-82). Baseline severity and remission by week 4 were validated in an independent cohort of 274 paediatric patients with newly diagnosed ulcerative colitis. After adjusting for clinical predictors, an antimicrobial peptide gene signature (odds ratio [OR] 0·57, 95% CI 0·39-0·81; p=0·002) and abundance of Ruminococcaceae (OR 1·43, 1·02-2·00; p=0·04), and Sutterella (OR 0·81, 0·65-1·00; p=0·05) were independently associated with week 52 corticosteroid-free remission. INTERPRETATION: Our findings support the utility of initial clinical activity and treatment response by 4 weeks to predict week 52 corticosteroid-free remission with mesalazine alone in children who are newly diagnosed with ulcerative colitis. The development of personalised clinical and biological signatures holds the promise of informing ulcerative colitis therapeutic decisions. FUNDING: US National Institutes of Health.

Free and Bioavailable 25-Hydroxyvitamin D Concentrations are Associated With Disease Activity in Pediatric Patients With Newly Diagnosed Treatment Naïve Ulcerative Colitis.

Background: Vitamin D regulates intestinal epithelial and immune functions, and vitamin D receptor deficiency increases the severity of murine colitis. Bioavailable 25-hydroxyvitamin D (25(OH)D) is available to target tissues and may be a driver of immune function. The aim is to evaluate the relationship of bioavailable 25(OH)D to the clinical expression of treatment naive pediatric ulcerative colitis (UC). Methods: The PROTECT (Predicting Response to Standardized Pediatric Colitis Therapy) study enrolled children ≤17 years newly diagnosed with UC. Free and total 25(OH)D were directly measured and 25(OH)D fractions were compared with disease activity measures. Results: Data were available on 388 subjects, mean age 12.7 years, 49% female, 84% with extensive/pancolitis. The median (IQR) total 25(OH)D concentration was 28.5 (23.9, 34.8) ng/mL, and 57% of subjects demonstrated insufficient vitamin D status (25(OH)D < 30 ng/mL). We found no evidence of association between total 25(OH)D and disease activity. Regression models adjusted for age, sex, race, and ethnicity demonstrated that an increase from 25th to 75th percentile for bioavailable and free 25(OH)D were associated with a mean (95th CI) decrease in the Pediatric Ulcerative Colitis Activity Index (PUCAI) of -8.7 (-13.7, -3.6) and -3.1 (-5.0, -1.2), respectively. No associations were detected between 25(OH)D fractions and fecal calprotectin or Mayo endoscopy score. Conclusions: Vitamin D insufficiency is highly prevalent in children with newly diagnosed UC. We found associations of free and bioavailable, but not total 25(OH)D, with PUCAI. Bioavailable vitamin D may contribute to UC pathophysiology and clinical activity.

Factors associated with early outcomes following standardised therapy in children with ulcerative colitis (PROTECT): a multicentre inception cohort study.

BACKGROUND: Previous retrospective studies of paediatric ulcerative colitis have had limited ability to describe disease progression and identify predictors of treatment response. In this study, we aimed to identify characteristics associated with outcomes following standardised therapy after initial diagnosis. METHODS: The PROTECT multicentre inception cohort study was based at 29 centres in the USA and Canada and included paediatric patients aged 4-17 years who were newly diagnosed with ulcerative colitis. Guided by the Pediatric Ulcerative Colitis Activity Index (PUCAI), patients received initial standardised treatment with mesalazine (PUCAI 10-30) oral corticosteroids (PUCAI 35-60), or intravenous corticosteroids (PUCAI ≥65). The key outcomes for this analysis were week 12 corticosteroid-free remission, defined as PUCAI less than 10 and taking only mesalazine, and treatment escalation during the 12 study weeks to anti-tumour necrosis factor α (TNFα) agents, immunomodulators, or colectomy among those initially treated with intravenous corticosteroids. We identified independent predictors of outcome through multivariable logistic regression using a per-protocol approach. This study is registered with ClinicalTrials.gov, number NCT01536535. FINDINGS: Patients were recruited between July 10, 2012, and April 21, 2015. 428 children initiated mesalazine (n=136), oral corticosteroids (n=144), or intravenous corticosteroids (n=148). Initial mean PUCAI was 31·1 (SD 13·3) in children initiating with mesalazine, 50·4 (13·8) in those initiating oral corticosteroids, and 66·9 (13·7) in those initiating intravenous corticosteroids (p<0·0001 for between-group comparison). Week 12 outcome data were available for 132 patients who initiated with mesalazine, 141 with oral corticosteroids, and 143 with intravenous corticosteroids. Corticosteroid-free remission with the patient receiving mesalazine treatment only at 12 weeks was achieved by 64 (48%) patients in the mesalazine group, 47 (33%) in the oral corticosteroid group, and 30 (21%) in the intravenous corticosteroid group (p<0·0001). Treatment escalation was required by nine (7%) patients in the mesalazine group, 21 (15%) in the oral corticosteroid group, and 52 (36%) in the intravenous corticosteroid group (p<0·0001). Eight patients, all of whom were initially treated with intravenous corticosteroids, underwent colectomy. Predictors of week 12 corticosteroid-free remission were baseline PUCAI less than 35 (odds ratio 2·44, 95% CI 1·41-4·22; p=0·0015), higher baseline albumin by 1 g/dL increments among children younger than 12 years (4·05, 1·90-8·64; p=0·00030), and week 4 remission (6·26, 3·79-10·35; p<0·0001). Predictors of treatment escalation by week 12 in patients initially treated with intravenous corticosteroids included baseline total Mayo score of 11 or higher (2·59, 0·93-7·21; p=0·068 [retained in model due to clinical relevance]), rectal biopsy eosinophil count less than or equal to 32 cells per high power field (4·55, 1·62-12·78; p=0·0040), rectal biopsy surface villiform changes (3·05, 1·09-8·56; p=0·034), and not achieving week 4 remission (30·28, 6·36-144·20; p<0·0001). INTERPRETATION: Our findings provide guidelines to assess the response of children newly diagnosed with ulcerative colitis to standardised initial therapy and identify predictors of treatment response and failure. These data suggest that additional therapeutic interventions might be warranted to improve early outcomes, especially in patients presenting with severe disease and requiring intravenous corticosteroids. FUNDING: National Institutes of Health.