OBJECTIVES
Antibodies to infliximab (ATIs) have been associated with loss of clinical response and lower serum infliximab (IFX) levels in some studies of patients with inflammatory bowel disease (IBD). This has important implications for patient management and development of novel biologic therapies. The objective of this study was to perform a systematic review and meta-analysis of studies that reported clinical outcomes and IFX levels according to patients’ ATI status.
METHODS
MEDLINE, Web of Science, CINAHL, Scopus, and EMBASE were searched for eligible studies. Quality assessment was undertaken using GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. Raw data from studies meeting inclusion criteria was pooled for meta-analysis of effect estimates. Sensitivity analysis was performed for all outcomes. Funnel plot was performed to assess for publication bias.
RESULTS
Thirteen studies met the inclusion criteria, and reported results in 1,378 patients with IBD. All included studies had a high risk of bias in at least one quality domain. The pooled risk ratio (RR) of loss of clinical response to IFX in patients with IBD who had ATIs was 3.2 (95 % confidence interval (CI): 2.0–4.9, P < 0.0001), when compared with patients without ATIs. This effect estimate was predominantly based on data from patients (N = 494) with Crohn’s disease (RR: 3.2, 95 % CI: 1.9–5.5, P < 0.0001). Data only from patients with ulcerative colitis (n = 86) exhibited a non-significant RR of loss of response of 2.2 (95 % CI: 0.5–9.0, P = 0.3) in those with ATIs. Heterogeneity existed between studies, in both methods of ATI detection, and clinical outcomes reported. Three studies (n = 243) reported trough serum IFX levels according to ATI status; the standardized mean difference in trough serum IFX levels between groups was −0.8 (95 % CI −1.2, −0.4, P < 0.0001). A funnel plot suggested the presence of publication bias.
CONCLUSIONS
The presence of ATIs is associated with a significantly higher risk of loss of clinical response to IFX and lower serum IFX levels in patients with IBD. Published studies on this topic lack uniform reporting of outcomes. High risk of bias was present in all the included studies.
The role of cytomegalovirus (CMV) in exacerbations of inflammatory bowel disease (IBD) remains a topic of ongoing debate. Current data are conflicting as to whether CMV worsens inflammation in those with severe colitis, or is merely a surrogate marker for severe disease. The interpretation of existing results is limited by mostly small, retrospective studies, with varying definitions of disease severity and CMV disease. CMV colitis is rare in patients with Crohn's disease or mild-moderate ulcerative colitis. In patients with severe and/or steroid-refractory ulcerative colitis, local reactivation of CMV can be detected in actively inflamed colonic tissue in about 30% of cases. Where comparisons between CMV+ and CMV- steroid-refractory patients can be made, most, but not all, studies show no difference in outcomes according to CMV status. Treatment with antiviral therapy has allowed some patients with severe colitis to avoid colectomy despite poor response to conventional IBD therapies. This article reviews the immunobiology of CMV disease, the evidence for CMV's role in disease severity, and discusses the outcomes with antiviral therapy.
Background
Infliximab (IFX) is effective in the treatment of inflammatory bowel disease; however, the effect is often not durable. It is unknown if proactive therapeutic concentration monitoring (TCM) of IFX improves outcomes.
Methods
This is a retrospective observational study examining the use of proactive TCM and titration of IFX to a target concentration for patients with inflammatory bowel disease in clinical remission at a tertiary care center. The primary aim was to describe the clinical course of patients who had proactive TCM. A secondary analysis was done to assess if this strategy was superior to the standard of care.
Results
Forty-eight patients were identified as having proactive TCM. Fifteen percent had an initial undetectable trough concentration. Twenty-five percent (12 of 48) of patients escalated IFX after the first proactive TCM while 15% (7 of 48) of patients de-escalated IFX therapy over the study period. A control group of 78 patients was identified. Patients who had proactive TCM had a greater probability of remaining on IFX than controls (hazard ratio, 0.3; 95% confidence interval, 0.1–0.6; log rank test; P = 0.0006). The probability of remaining on IFX was greatest for patients who achieved a trough concentration >5 μg/mL (hazard ratio, 0.03; 95% confidence interval, 0.01–0.1; P < 0.0001 versus trough <5 μg/mL). Fewer patients in the proactive TCM group stopped IFX (10% versus 31%, P = 0.009).
Conclusions
In this pilot observational study, proactive TCM of IFX frequently identified patients with low or undetectable trough concentrations and resulted in a greater probability of remaining on IFX.
Background
The microbiota in the lumen of patients with Crohn’s disease (CD) is characterized by reduced diversity, particularly Firmicutes and Bacteroidetes. It is unknown whether the introduction of the intestinal microbiota from healthy individuals could correct this dysbiosis and reverse mucosal inflammation. We investigated the response to fecal microbial transplantation (FMT) from healthy individuals to subjects with active CD
Methods
We performed a prospective open-label study (uncontrolled) of FMT from healthy donors to subjects with active CD. A single FMT was performed via colonoscopy. Recipients’ microbial diversity, mucosal T-cell phenotypes and clinical and inflammatory parameters were measured over 12 weeks, and safety over 26 weeks.
Results
Nineteen subjects were treated with FMT and completed the study follow-up. Fifty-eight percent (11/19) demonstrated a clinical response (HBI decrease > 3) following FMT. Fifteen subjects had sufficient pre/post fecal samples for analysis. A significant increase in microbial diversity occurred after FMT (p=0.02). This was greater in clinical responders than non-responders. Patients who experienced a clinical response demonstrated a significant shift in fecal microbial composition towards their donor’s profile as assessed by the Bray-Curtis index at 4 weeks (p=0.003). An increase in regulatory T-cells (CD4+CD25+CD127lo) was also noted in recipients’ lamina propria following FMT. No serious adverse events were noted over the 26-week study period.
Conclusion
In this open label study, FMT led to an expansion in microbial bacterial diversity in patients with active CD. FMT was overall safe, although the clinical response was variable. Determining donor microbial factors that influence clinical response is needed prior to randomized clinical trials of FMT in CD.
ClinicalTrials ID # NCT01847170
There are insufficient randomised controlled trials of infliximab, budesonide, tenovil and interleukin-10 to draw conclusions. Nitro-imidazole antibiotics, mesalamine and immunosuppressive therapy with azathioprine/6-MP or infliximab all appear to be superior to placebo for the prevention of post-operative recurrence of Crohn's disease. The cost, toxicity and tolerability of these approaches require careful consideration to determine the optimal approach for post-operative prophylaxis.
Histology grade has the strongest association with the risk of clinical relapse in patients with UC who are in clinical remission. Consideration should be given to including this end point in evaluating therapy for UC.
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