The development of a magnetic resonance imaging index for fistulising Crohn's disease

BACKGROUND

Magnetic resonance imaging (MRI) is the gold standard for assessment of perianal fistulising Crohn's disease (CD). The Van Assche index is the most commonly used MRI fistula index.

AIMS

To assess the reliability of the Van Assche index, and to modify the instrument to improve reliability and create a novel index for fistulising CD.

METHODS

A consensus process developed scoring conventions for existing Van Assche index component items and new items. Four experienced radiologists evaluated 50 MRI images in random order on three occasions. Reliability was assessed by estimates of intraclass correlation coefficients (ICCs). Common sources of disagreement were identified and recommendations made to minimise disagreement. A mixed effects model used a 100 mm visual anologue scale (VAS) for global severity as outcome and component items as predictors to create a modified Van Assche index.

RESULTS

Intraclass correlation coefficients (95% confidence intervals) for intra-rater reliability of the original and modified Van Assche indices and the VAS were 0.86 (0.81-0.90), 0.90 (0.86-0.93) and 0.86 (0.82-0.89). Corresponding ICCs for inter-rater reliability were 0.66 (0.52-0.76), 0.67 (0.55-0.75) and 0.58 (0.47-0.66). Sources of disagreement included number, location, and extension of fistula tracts, and rectal wall involvement. A modified Van Assche index (range 0-24) was created that included seven component items.

CONCLUSIONS

Although "almost perfect" intra-rater reliability was observed for the assessment of MRI images for fistulising CD using the Van Assche index, inter-rater reliability was considerably lower. Our modification of this index should result in a more optimal instrument.

Systematic review with meta-analysis: placebo rates in induction and maintenance trials of Crohn's disease

BACKGROUND

Minimising placebo response is essential for drug development.

AIM

To conduct a meta-analysis to determine placebo response and remission rates in trials and identify the factors affecting these rates.

METHODS

MEDLINE, EMBASE and CENTRAL were searched from inception to April 2014 for placebo-controlled trials of pharmacological interventions for Crohn's disease. Placebo response and remission rates for induction and maintenance trials were pooled by random-effects and mixed-effects meta-regression models to evaluate effects of study-level characteristics on these rates.

RESULTS

In 100 studies containing 67 induction and 40 maintenance phases and 7638 participants, pooled placebo remission and response rates for induction trials were 18% [95% confidence interval (CI) 16-21%] and 28% (95% CI 24-32%), respectively. Corresponding values for maintenance trials were 32% (95% CI 25-39%) and 26% (95% CI 19-35%), respectively. For remission, trials enrolling patients with more severe disease activity, longer disease duration and more study centres were associated with lower placebo rates, whereas more study visits and longer study duration was associated with higher placebo rates. For response, findings were opposite such that trials enrolling patients with less severe disease activity and longer study duration were associated with lower placebo rates. Placebo rates varied by drug class and route of administration, with the highest placebo response rates observed for biologics.

CONCLUSIONS

Placebo rates vary according to whether trials are designed for induction or maintenance and the factors influencing them differ for the endpoints of remission and response. These findings have important implications for clinical trial design in Crohn's disease.

IOIBD technical review on endoscopic indices for Crohn's disease clinical trials

BACKGROUND

Crohn's disease (CD) is a chronic disabling and progressive IBD. Only strategies looking beyond symptoms and based on tight monitoring of objective signs of inflammation such as mucosal lesions may have the potential for disease modification. Endoscopic evaluation is currently the gold standard to assess mucosal lesions and has become a major therapeutic endpoint in clinical trials. Several endoscopic indices have been proposed to evaluate disease activity; unvalidated and arbitrary definitions have been used in clinical trials for defining endoscopic response and endoscopic remission in CD.

METHODS

In these recommendations from the International Organization for the Study of Inflammatory Bowel Disease, we first reviewed all technical aspects of available endoscopic scoring systems in the literature. Second, in order to achieve consensus on endoscopic definitions of remission and response in trials, a two-round vote based on a Delphi method was performed among 14 specialists in the field of IBDs.

RESULTS

At the end of the voting process, the investigators ranked first a >50% decrease in Simple Endoscopic Score for Crohn's Disease (SES-CD) or Crohn's Disease Endoscopic Index of Severity for the definition of endoscopic response, and an SES-CD 0-2 for the definition of endoscopic remission in CD. All experts agreed on a Rutgeerts' score i0-i1 for the definition of endoscopic remission after surgery.

Randomised clinical trial: a phase 1, dose-ranging study of the anti-matrix metalloproteinase-9 monoclonal antibody GS-5745 versus placebo for ulcerative colitis

BACKGROUND

Matrix metalloproteinase-9 is a proteolytic enzyme whose expression is increased in ulcerative colitis.

AIM

To evaluate the safety and efficacy of GS-5745, a fully humanised anti-matrix metalloproteinase-9 monoclonal antibody, in moderately-to-severely active ulcerative colitis.

METHODS

We randomised 74 patients with ulcerative colitis to treatment with single or multiple ascending intravenous or subcutaneous doses of GS-5745 or placebo. Multiple-dose cohorts received either IV infusions (0.3, 1.0, 2.5 or 5.0 mg/kg GS-5745 or placebo) every 2 weeks (three total IV infusions) or five weekly SC injections (150 mg GS-5745 or placebo). The primary outcomes were the safety, tolerability and pharmacokinetics of escalating single and multiple doses of GS-5745. Exploratory analyses in the multiple-dose cohorts included clinical response (≥3 points or 30% decrease from baseline in Mayo Clinic score and ≥1 point decrease in the rectal bleeding subscore or a rectal bleeding subscore ≤1) and clinical remission (a complete Mayo Clinic score ≤2 with no subscore >1) at Day 36. Biological effects associated with a clinical response to GS-5745 were explored using histological and molecular approaches.

RESULTS

Twenty-three of the 42 patients (55%) receiving multiple doses of GS-5745 had adverse events, compared with 5/8 patients (63%) receiving placebo. GS-5745 showed target-mediated drug disposition, approximately dose-proportional increases in maximum plasma concentration and more than dose-proportional increases in the area under the plasma drug concentration-time curve. Clinical response occurred in 18/42 patients (43%) receiving GS-5745 compared with 1/8 patients (13%) receiving placebo. Clinical remission occurred in 6/42 patients (14%) receiving GS-5745 and 0/8 (0%) receiving placebo. Patients with a clinical response to GS-5745 had reductions in matrix metalloproteinase-9 tissue levels (mean 48.9% decrease from baseline compared with a mean 18.5% increase in nonresponders, P = 0.008) significant improvements in histopathology scores (confirmed with three separate histological disease activity indices), as well as changes in colonic gene expression that were consistent with reduced inflammation.

CONCLUSION

This phase 1 trial provides preliminary evidence for the safety and therapeutic potential of GS-5745 in the treatment of ulcerative colitis.

Development of interim patient-reported outcome measures for the assessment of ulcerative colitis disease activity in clinical trials

BACKGROUND

Patient-reported outcomes (PROs) have an increasingly important role in the evaluation of new therapies for inflammatory bowel disease. The US Food and Drug Administration has issued formal guidance to describe the role of PRO instruments in evaluation of claims for product labelling. However, no validated PRO exists for ulcerative colitis.

AIM

To investigate whether the PROs from the Mayo Clinic Score (MCS) for UC can be modified, to develop an interim PRO for use in clinical trials, alone or in combination with endoscopy.

METHODS

Data from an induction trial of a mesalazine (mesalamine) formulation were used to compare effect sizes between mesalazine and placebo for PRO items (stool frequency and rectal bleeding) alone and in combination with endoscopy. The operating properties of the PRO were validated using data from a phase 2 trial of MLN02, a humanised antibody to the α4β7 integrin in patients with UC.

RESULTS

A two-item PRO (PRO2) consisting of rectal bleeding = 0 and stool frequency ≤1 or ≤2, combined with an endoscopy subscore ≤1 yielded statistically significant differences between active drug and placebo. This combination yielded the most similar effect sizes and placebo rates for remission, compared to the primary trials. Use of PRO items alone yielded high placebo remission rates in both data sets, although rates were lower when the items were combined and remission defined as PRO2 = 0.

CONCLUSION

Patient-reported outcomes items derived from the Mayo Clinic Score combined with endoscopy as a co-primary endpoint may be an appropriate interim outcome measure for ulcerative colitis trials.

Review article: pharmacological aspects of anti-TNF biosimilars in inflammatory bowel diseases

BACKGROUND

Anti-tumour necrosis factor (anti-TNF) monoclonal antibodies have shown efficacy in inflammatory bowel diseases (IBD). As these therapies lose patent protection, biosimilar versions of the originator products are being developed, such as the infliximab biosimilar CT-P13; however, some uncertainty exists regarding their pharmacology in IBD.

AIM

To review the literature on anti-TNF biosimilars focusing on pharmacokinetics, pharmacodynamic properties and comparative effectiveness, related to their use in IBD.

METHODS

A PubMed literature search was performed using the following terms individually or in combination: 'biosimilars,' 'CT-P13,' 'Crohn's disease,' 'inflammatory bowel disease,' 'ulcerative colitis,' 'anti-TNFα therapy,' 'infliximab,' 'adalimumab,' 'pharmacokinetics,' 'immunogenicity.'

RESULTS

Bioequivalence of CT-P13 and infliximab was shown in ankylosing spondylitis (AS) and therapeutic equivalence in rheumatoid arthritis (RA). Preliminary results of CT-P13 in IBD come from small post-marketing registries and case series with a relatively short-term follow-up period and suggest comparable efficacy and safety to infliximab. Inter- and intra-individual differences in exposure and response are well known for the original molecules but dosing regimens and concomitant medications are different for RA compared to IBD, limiting the ability to translate some of the pharmacology data in RA to IBD. Uncertainty exists about cross-reactivity of anti-drug antibodies and whether similar exposure-response relationships will be observed for biosimilars and efficacy thresholds for therapeutic drug monitoring can be used interchangeably.

CONCLUSIONS

It is likely that biosimilars will be widely used for the treatment of IBD due to their cost savings and comparable efficacy. Nevertheless, robust post-marketing studies and pharmacovigilance are warranted in the coming years.

A retrospective analysis: the development of patient reported outcome measures for the assessment of Crohn's disease activity

BACKGROUND

The Crohn's Disease Activity Index (CDAI) is a measure of disease activity based on symptoms, signs and a laboratory test. The US Food and Drug Administration has indicated that patient reported outcomes (PROs) should be the primary outcome in randomised controlled trials for Crohn's disease (CD).

AIM

As no validated PRO exists for CD, to investigate whether CDAI diary card items could be modified for this purpose.

METHODS

Data from a trial of rifaximin-extended intestinal release were used to identify cut-points for stool frequency, pain and general well-being using receiver operating characteristic curves with CDAI <150 as criterion. The operating properties of 2- and 3-item PRO were evaluated using data from a trial of methotrexate in CD. Regression analysis determined PRO2 and PRO3 scores that correspond to CDAI-defined thresholds of 150, 220 and 450 and changes of 50, 70 and 100 points.

RESULTS

Optimum cut-points for CDAI remission were mean daily stool frequency ≤1.5, abdominal pain ≤1, and general well-being score of ≤1 (areas under the ROC curve 0.79, 0.91 and 0.89, respectively). The effect estimates were similar using 2- and 3-item PROs or CDAI. PRO2 and PRO3 values corresponding to CDAI scores of 150, 220 and 450 points were 8, 14, 34 and 13, 22, 53. The corresponding values for CDAI changes of 50, 70 and 100, were 2, 5, 8 and 5, 9, 14. Responsiveness to change was similar for both PROs.

CONCLUSION

Patient reported outcomes derived from CDAI diary items may be appropriate for use in clinical trials for CD.

A prospective cohort study to determine the relationship between serum infliximab concentration and efficacy in patients with luminal Crohn's disease

BACKGROUND

Patients with Crohn's disease (CD) may experience disease relapse on maintenance infliximab. Anti-drug antibodies likely contribute to loss of response, and serum infliximab levels likely correlate with efficacy.

AIM

To prospectively evaluate the relationship between trough serum infliximab concentration and disease activity.

METHODS

Adult patients (N = 327) with a diagnosis of CD who had received at least five consecutive infliximab infusions and who planned to receive at least two additional infusions were enrolled. The Crohn's Disease Activity Index (CDAI), serum infliximab, C-reactive protein (CRP) and antibodies-to-infliximab (ATI) were assessed at baseline, week 4 and week 8. Receiver operating characteristic (ROC) analysis examined the relationship between infliximab concentrations and disease activity.

RESULTS

The mean CDAI score, which decreased 1.05 points between infusions, did not correlate with the mean change in trough infliximab concentration (+0.39 μg/mL; r = 0.099, P = 0.083), but was associated with the mean change in CRP concentration (r = 0.19, P < 0.001). Trough infliximab concentrations below 2.8-4.6 μg/mL best predicted a ≥ 70 point increase in the CDAI between infusions, and those below 2.7-2.8 μg/mL best predicted CRP >5 mg/mL at the second infusion. ATI at either visit decreased the proportion of patients with therapeutic infliximab trough levels compared with patients who were ATI negative (17.5% vs. 77.3% at visit 1 and 13.8% vs. 75.6% at visit 3; P < 0.001 for both comparisons).

CONCLUSIONS

This prospective study confirms the relationship between trough infliximab concentrations, inflammation and antibodies-to-infliximab. Infliximab trough concentrations below 3 μg/mL may increase the likelihood of symptoms and inflammation (ClinicalTrials.gov identifier: NCT00676988).

HIV testing among young adults and older adolescents in the setting of acute substance abuse treatment

OBJECTIVES

To examine the feasibility and acceptance of HIV testing among youth in acute substance abuse treatment.

METHODS

Youth, aged 18 to 25 years old, in state-funded inpatient detoxification completed a confidential demographic/risk behavior questionnaire, and were offered a choice of no testing, serum-based testing, or oral fluid (Orasure, Epitope, Inc., Beaverton, OR, U.S.A.) HIV testing.

RESULTS

In all, 74% of 204 participants accepted HIV testing. In a multivariate model, female gender (odds ratio [OR], 0.32; 95% confidence interval [CI] 0.14-0.74) and having been recently tested (OR, 0.11; 95% CI, 0.05-0.26) were independently associated with refusing testing. Recent sexual activity (OR, 5.4; 95% CI, 1.5-20.4), recent use of methamphetamines (speed) or a combination of cocaine and heroin (speedball) (OR, 3.8; 95% CI, 1.6-9.0), and a recent perceived risk for HIV (OR, 4.6; 95% CI, 1.9-10.9) were independently associated with test acceptance. Thus, 150 of 150 (100%) chose the Orasure test. Overall, 64.6% (97 of 150) of those tested received their results, but among participants requiring a follow-up appointment to learn test results, only 9.2% (8 of 87) returned.

CONCLUSIONS

HIV testing is feasible and acceptable in this population. All patients preferred Orasure testing to a serum enzyme-linked immunosorbent assay (ELISA). Most youth tested in detoxification will only learn their results if they are provided during treatment. Rapid HIV testing with same-day results could improve follow-up rates.