No association between C-reactive protein gene polymorphisms and decrease of C-reactive protein serum concentration after infliximab treatment in Crohn's disease

C-Reactive Protein +1444C/T Polymorphism Is Associated with the Susceptibility to Pulmonary Tuberculosis

Objective

The T allele of C-reactive protein (CRP) +1444C/T (rs1130864) polymorphism was associated with increased risk for some inflammatory conditions. The objective of the study was to explore the association between the CRP +1444C/T polymorphism with the susceptibility to pulmonary tuberculosis (PTB) in a Chinese population.

Methods

This case-control study enrolled 480 PTB patients and 480 healthy controls. The CRP +1444C/T polymorphism was determined using Sanger sequencing. The odds ratio (OR) and 95% confidence interval (CI) were assessed to examine the strength of genetic correlation.

Results

The genotype and allele frequencies of PTB patients differed from controls (CT vs. CC, OR = 1.924, 95% CI: 1.099-3.371, adjusted P value = 0.022; T vs. C, OR = 1.884, 95% CI: 1.085-3.273, adjusted P value = 0.024). Stratified analysis by sex found that PTB patients' genotype and allele frequencies differed from controls in the male subgroup but not the female subgroup.

Conclusion

In conclusion, the minor T allele of CRP +1444C/T polymorphism was associated with increased PTB risk.

Defining the Path Forward for Biomarkers to Address Unmet Needs in Inflammatory Bowel Diseases

Despite major advances in the inflammatory bowel diseases field, biomarkers to enable personalized and effective management are inadequate. Disease course and treatment response are highly variable, with some patients experiencing mild disease progression, whereas other patients experience severe or complicated disease. Periodic endoscopy is performed to assess disease activity; as a result, it takes months to ascertain whether a treatment is having a positive impact on disease progression. Minimally invasive biomarkers for prognosis of disease course, prediction of treatment response, monitoring of disease activity, and accurate diagnosis based on improved disease phenotyping and classification could improve outcomes and accelerate the development of novel therapeutics. Rapidly developing technologies have great potential in this regard; however, the discovery, validation, and qualification of biomarkers will require partnerships including academia, industry, funders, and regulators. The Crohn's & Colitis Foundation launched the IBD Biomarker Summit to bring together key stakeholders to identify and prioritize critical unmet needs; prioritize promising technologies and consortium approaches to address these needs; and propose harmonization approaches to improve comparability of data across studies. Here, we summarize the outcomes of the 2018 and 2019 meetings, including consensus-based unmet needs in the clinical and drug development context. We highlight ongoing consortium efforts and promising technologies with the potential to address these needs in the near term. Finally, we summarize actionable recommendations for harmonization, including data collection tools for improved consistency in disease phenotyping; standardization of informed consenting; and development of guidelines for sample management and assay validation. Taken together, these outcomes demonstrate that there is an exceptional alignment of priorities across stakeholders for a coordinated effort to address unmet needs of patients with inflammatory bowel diseases through biomarker science.

Predictors of Primary Response to Biologic Treatment [Anti-TNF, Vedolizumab, and Ustekinumab] in Patients With Inflammatory Bowel Disease: From Basic Science to Clinical Practice

BACKGROUND

Inflammatory bowel diseases [IBD]-ulcerative colitis and Crohn's disease-are commonly treated with biologic drugs. However, only approximately two-thirds of patients have an initial response to these therapies. Personalised medicine has the potential to optimise efficacy, decrease the risk of adverse drug events, and reduce costs by establishing the most suitable therapy for a selected patient.

AIM

The present study reviews the potential predictors of short-term primary response to biologic treatment, including not only anti-tumour necrosis factor [TNF] agents [such as infliximab, adalimumab, certolizumab, and golimumab] but also vedolizumab and ustekinumab.

METHODS

We performed a systematic bibliographical search to identify studies investigating predictive factors of response to biologic therapy.

RESULTS

For anti-TNF agents, most of the evaluated factors have not demonstrated usefulness, and many others are still controversial. Thus, only a few factors may have a potential role in the prediction of the response, including disease behaviour/phenotype, disease severity, C-reactive protein, albumin, cytokine expression in serum, previous anti-TNF therapy, some proteomic markers, and some colorectal mucosa markers. For vedolizumab, the availability of useful predictive markers seems to be even lower, with only some factors showing a limited value, such as the expression of α4β7 integrin in blood, the faecal microbiota, some proteomic markers, and some colorectal mucosa markers. Finally, in the case of ustekinumab, no predictive factor has been reported yet to be helpful in clinical practice.

CONCLUSION

In summary, currently no single marker fulfils all criteria for being an appropriate prognostic indicator of response to any biologic treatment in IBD.

The association between the C-reactive protein gene +1444C/T polymorphism and Parkinson's disease susceptibility in a Chinese population

OBJECTIVE

C-reactive protein (CRP) is increased in Parkinson's disease (PD). The CRP +1444C/T (rs1130864) polymorphism is located in the 3' untranslated region (3'-UTR) and is associated with serum CRP concentrations. We explored the relationship between the CRP +1444C/T polymorphism and susceptibility to PD.

METHODS

A total of 1000 subjects from a Chinese population were recruited into this case-control study, including 500 PD patients and 500 healthy controls. The genotype of the CRP +1444C/T polymorphism was tested by Sanger sequencing, and the Hardy-Weinberg equilibrium (HWE) was assessed in the groups. The odds ratios and 95% confidence intervals were calculated to evaluate the strength of any correlations in allelic, dominant, recessive, and additive genetic models.

RESULTS

The genotypic distribution of the CRP +1444C/T polymorphism was consistent with HWE in controls, and markedly different with cases. The CRP +1444C/T polymorphism was associated with increased PD risk in allelic and dominant models in the overall and male population, but not the female subgroup.

CONCLUSION

The presence of a CRP +1444C/T polymorphism may be associated with an increased risk of PD in our Chinese population. Given the missing support for a role of this SNP in PD in the pre-existing GWAS, the SNP may not be genuinely associated with PD despite some positive candidate gene studies.

Predictors of Long-term Clinical and Endoscopic Remission in Children With Crohn Disease Treated With Infliximab

OBJECTIVES

We aimed to identify early noninvasive predictors of clinical and endoscopic remission in children with Crohn disease (CD) under infliximab (IFX).

METHODS

Prospective observational study conducted in children with moderate-to-severe CD starting IFX. All patients underwent weighted pediatric CD activity index (wPCDAI) assessment, C-reactive protein and fecal calprotectin (FC) at week 0, 14, and 48. Endoscopy was performed at 0 and 48 weeks. The primary outcome was to determine the ability of 14-week wPCDAI, C-reactive protein, and FC to predict 1-year steroid-free clinical remission and mucosal healing. As a secondary outcome we evaluated their concordance with Simple Endoscopic Score for CD (SES-CD) at week 48.

RESULTS

Forty-one children were enrolled. At 1 year, 21 (51%) and 16 (39%) were in clinical and endoscopic remission. Only combined postinduction FC and wPCDAI were able to predict 1-year clinical and endoscopic remission (hazard ratio 4.81 [95% confidence interval 1.76-20.45], P = 0.05 and hazard ratio 5.51 [95% confidence interval 1.83-26.9], P = 0.03). One-year SES-CD moderately correlated with FC (r = 0.52; P = 0.001). The FC cut-off value for mucosal healing was 120.5 μg/g (area under the curve 0.863, 83% sensitivity, 75.5% specificity; P = 0.005). The concordance between wPCDAI and SES-CD was excellent and good for severe disease and remission (k 0.87 and 0.76).

CONCLUSIONS

Post induction FC combined with wPCDAI can predict 1-year clinical and endoscopic response to IFX in pediatric CD. FC shows a moderate correlation with SES-CD, whereas wPCDAI has a good concordance with endoscopic remission or severe disease, but not with mild and moderate disease.

Pre-Treatment Biomarkers of Anti-Tumour Necrosis Factor Therapy Response in Crohn's Disease-A Systematic Review and Gene Ontology Analysis

The most prominent treatment for the serious cases of Crohn’s disease (CD) are biological tumour necrosis factor (TNF) inhibitors. Unfortunately, therapy nonresponse is still a serious issue in ~1/3 of CD patients. Accurate prediction of responsiveness prior to therapy start would therefore be of great value. Clinical predictors have, however, proved insufficient. Here, we integrate genomic and expression data on potential pre-treatment biomarkers of anti-TNF nonresponse. We show that there is almost no overlap between genomic (annotated with tissue-specific expression quantitative trait loci data) and transcription (RNA and protein data) biomarkers. Furthermore, using interaction networks we demonstrate there is little direct interaction between the proposed biomarkers, though a majority do have common interactors connecting them into networks. Our gene ontology analysis shows that these networks have roles in apoptotic signalling, response to oxidative stress and inflammation pathways. We conclude that a more systematic approach with genome-wide search of genomic and expression biomarkers in the same patients is needed in future studies.

Systematic review: predictive biomarkers of therapeutic response in inflammatory bowel disease-personalised medicine in its infancy

BACKGROUND

Inflammatory bowel disease (IBD) is characterised by substantial heterogeneity in treatment response. With an expanding number of therapeutic agents, identifying optimal treatment at the patient level remains a major challenge.

AIM

To systematically review the available literature on predictive biomarkers of therapeutic response in IBD.

METHODS

An electronic literature search was performed on 30 January 2018 using MEDLINE, EMBASE and the Cochrane Library. Retrospective, prospective, uncontrolled and controlled studies reporting on biomarkers predicting therapeutic response in paediatric and adult IBD populations were eligible for inclusion. The methodological quality of the included studies was assessed using the QUIPS tool. Due to anticipated heterogeneity and limited data, a qualitative, rather than quantitative, assessment was planned.

RESULTS

Of the 10 638 citations identified, 92 articles met the inclusion criteria. Several potential DNA, mRNA and protein markers were evaluated as predictive biomarkers. Most studies focused on predicting response to anti-TNF agents. Substantial between-study heterogeneity was identified with respect to both the biomarkers studied and the definition of response. None of the included studies received a low risk of bias rating for all six domains. Currently, none of the biomarkers is sufficiently predictive for clinical use.

CONCLUSIONS

The search for predictive biomarkers is still in its infancy and current evidence is limited. Future research efforts should take into account the high patient heterogeneity within prospective trials with objective response assessment. Predictive models will most likely comprise a combination of several molecular markers from integrated omics-levels and clinical characteristics.

Raised faecal calprotectin is associated with subsequent symptomatic relapse, in children and adolescents with inflammatory bowel disease in clinical remission

BACKGROUND

Reliable data on inflammatory biomarkers for predicting relapse of paediatric inflammatory bowel disease (IBD) are lacking.

AIM

To investigate the predictive value of faecal calprotectin (FC) and CRP for symptomatic relapse in pediatric IBD in clinical remission.

METHODS

In this cross-sectional cohort study, patients <18 years with Crohn's disease or ulcerative colitis in clinical remission ≥3 months were included. At baseline, clinical and biochemical disease activity were assessed using the abbreviated-Pediatric Crohn's Disease Activity Index or Pediatric Ulcerative Colitis Activity Index, and FC and CRP respectively. Disease course over the subsequent 12 months was retrospectively assessed.

RESULTS

In total, 114 patients (56% males; median age 14.9 years) were included. Baseline FC was higher in patients that developed symptomatic relapse [median (IQR), relapse 370 μg/g (86-1100) vs. remission 122 μg/g (40-344), P = 0.003]. Baseline FC was predictive of symptomatic relapse within 6 months [HR per 250 μg/g (95% CI): 1.46 (1.21-1.77), P < 0.001], with good predictive accuracy (AUC: 0.82). Optimal FC cut-off was 350 μg/g, with positive and negative predictive value of 41% and 96%. Baseline CRP was higher in patients that developed symptomatic relapse [median (IQR), relapse 1.0 μg/g (0.6-5.0) vs. remission 1.0 μg/g (0.4-2.0), P = 0.033]. Baseline CRP was predictive of symptomatic relapse within 6 months from baseline [HR per 1 mg/L (95% CI): 1.10 (1.02-1.19), P = 0.011], with fair predictive accuracy (AUC: 0.72). Optimal CRP cut-off was 1.0 mg/L, with positive and negative predictive value of 21% and 94%.

CONCLUSIONS

Faecal calprotectin and CRP are predictive of symptomatic relapse and may be valuable in management of paediatric IBD in clinical remission.

Systematic review: genetic biomarkers associated with anti-TNF treatment response in inflammatory bowel diseases

BACKGROUND

Personalised medicine, including biomarkers for treatment selection, may provide new algorithms for more effective treatment of patients. Genetic variation may impact drug response and genetic markers could help selecting the best treatment strategy for the individual patient.

AIM

To identify polymorphisms and candidate genes from the literature that are associated with anti-tumour necrosis factor (TNF) treatment response in patients with inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis.

METHODS

We performed a PubMed literature search and retrieved studies reporting original data on association between polymorphisms and anti-TNF treatment response and conducted a meta-analysis.

RESULTS

A functional polymorphism in FCGR3A was significantly associated with anti-TNF treatment response among CD patients using biological response criterion (decrease in C-reactive protein, levels). Meta-analyses showed that polymorphisms in TLR2 (rs3804099, OR (95% CI) = 2.17 (1.35-3.47)], rs11938228 [OR = 0.64 (0.43-0.96)], TLR4 (rs5030728) [OR = 3.18 (1.63-6.21)], TLR9 (rs352139) [OR = 0.43 (0.21-0.88)], TNFRSF1A (rs4149570) [OR = 2.06 (1.02-4.17)], IFNG (rs2430561) [OR = 1.66 (1.05-2.63)], IL6 (rs10499563) [OR = 1.65 (1.04-2.63)] and IL1B (rs4848306) [OR = 1.88 (1.05-3.35)] were significantly associated with response among IBD patients using clinical response criteria. A positive predictive value of 0.96 was achieved by combining five genetic markers in an explorative analysis.

CONCLUSIONS

There are no genetic markers currently available which are adequately predictive of anti-TNF response for use in the clinic. Genetic markers bear the advantage that they do not change over time. Therefore, hypothesis-free approaches, testing a large number of polymorphisms in large, well-characterised cohorts, are required in order to identify genetic profiles with larger effect sizes, which could be employed as biomarkers for treatment selection in clinical settings.

Systematic review: predicting and optimising response to anti-TNF therapy in Crohn's disease - algorithm for practical management

BACKGROUND

Nonresponse and loss of response to anti-TNF therapies in Crohn's disease represent significant clinical problems for which clear management guidelines are lacking.

AIM

To review the incidence, mechanisms and predictors of primary nonresponse and secondary loss of response to formulate practical clinical algorithms to guide management.

METHODS

Through a systematic literature review, 503 articles were identified which fit the inclusion criteria.

RESULTS

Primary nonresponse to anti-TNF treatment affects 13-40% of patients. Secondary loss of response to anti-TNF occurs in 23-46% of patients when determined according to dose intensification, and 5-13% of patients when gauged by drug discontinuation rates. Recent evidence suggests that the mechanisms underlying primary nonresponse and secondary loss of response are multifactorial and include disease characteristics (phenotype, location, severity); drug (pharmacokinetic, pharmacodynamic or immunogenicity) and treatment strategy (dosing regimen) related factors. Clinical algorithms that employ therapeutic drug monitoring (using anti-TNF tough levels and anti-drug antibody levels) may be used to determine the underlying cause of primary nonresponse and secondary loss of response respectively and guide clinicians as to which patients are most likely to respond to anti-TNF therapy and help optimise drug therapy for those who are losing response to anti-TNF therapy.

CONCLUSIONS

Nonresponse or loss of response to anti-TNF occurs commonly in Crohn's disease. Clinical algorithms utilising therapeutic drug monitoring may establish the mechanisms for treatment failure and help guide the subsequent therapeutic approach.

Current stage in inflammatory bowel disease: What is next?

In recent years, the incidence of inflammatory bowel disease (IBD) has been on the rise, extending to countries where it was infrequent in the past. As a result, the gap between high and low incidence countries is decreasing. The disease, therefore, has an important economic impact on the healthcare system. Advances in recent years in pharmacogenetics and clinical pharmacology have allowed for the development of treatment strategies adjusted to the patient profile. Concurrently, new drugs aimed at inflammatory targets have been developed that may expand future treatment options. This review examines advances in the optimization of existing drug treatments and the development of novel treatment options for IBD.

Pharmacokinetics and concentration-effect relationship of adalimumab in rheumatoid arthritis

AIMS

This study aimed at describing adalimumab pharmacokinetics (PK) and the concentration-effect relationship of adalimumab using pharmacokinetic-pharmacodynamic (PK-PD) modelling in patients with rheumatoid arthritis (RA).

METHODS

Adalimumab PK and PK-PD data were obtained from a multicentric observational study. Adalimumab (40 mg) was administered subcutaneously every other week, and its pharmacokinetics was described using a one-compartment model. The relationship between adalimumab concentration and C-reactive protein (CRP) concentration was described using an indirect response model with inhibition of CRP input, whereas the relationship between adalimumab concentration and disease activity score in 28 joints (DAS28) was described using a direct inhibition model. Dose regimens that included a loading dose of adalimumab were simulated.

RESULTS

Thirty patients treated for RA were analysed. The following pharmacokinetic and PK-PD parameters were estimated (interidividual coefficient of variation): apparent volume of distribution (Vd /F) = 10.8 l (92%); apparent clearance (CL/F) = 0.32 l day(-1) (17%); first-order absorption rate (ka ) = 0.28 day(-1) ; CRP input (kin ) = 22.0 mg l(-1)  day(-1) (65%); adalimumab concentration leading to a 50% decrease in kin (C50 ) = 3.6 mg l(-1) (88%); baseline DAS28 (DAS0 ) = 5.5 mg l(-1) (11%); and adalimumab concentration leading to 50% decrease of DAS0 (IC50 ) = 11.0 mg l(-1) (71%). Simulations showed that a 160 mg loading dose should reduce the time to reach efficacy in terms of both CRP and DAS28 after the first injection.

CONCLUSIONS

This is the first study to describe adalimumab pharmacokinetics and the concentration-effect relationship in RA. A 160 mg loading dose may lead to an increased benefit from treatment in RA patients.

Serum C-reactive protein and CRP genotype in pediatric inflammatory bowel disease: influence on phenotype, natural history, and response to therapy

BACKGROUND

C-reactive protein (CRP) is an acute phase reactant. Patients with pediatric inflammatory bowel disease (PIBD) differ from adult patients with inflammatory bowel disease with regard to phenotype, inflammatory profile, and treatment response. We hypothesized that variations in CRP and CRP genotype influence PIBD phenotype, natural history, and remission after anti-tumor necrosis factor alpha therapy.

METHODS

Six single nucleotide polymorphisms tagging CRP (rs1935193, rs1130864, rs1205, rs1417938, rs11265263, and rs1800947) were genotyped in 465 patients with PIBD (diagnosed <17 yr). Phenotyping was serially performed until last follow-up and serum CRP levels recorded at diagnosis and before biological therapy in a subgroup.

RESULTS

CRP haplotype (ATGCTC) differed in those diagnosed <10 years, with rs1205T more frequent in Crohn's disease (CD) than ulcerative colitis (UC) (P = 0.009); the haplotype ATGCTC was less frequent in UC (P = 0.002). Three single nucleotide polymorphisms (rs1205, rs1130864, and rs1417938) showed association with elevated CRP levels at diagnosis. CRP genotype had no association with CD phenotype or natural history. CRP was more frequently raised at diagnosis in CD than UC (63% versus 22%, P < 0.0001). Elevated CRP at diagnosis was associated with a higher risk of progression to surgery in patients with CD (P < 0.0001) and the need for azathioprine in the overall PIBD cohort (P = 0.002). There was no effect of CRP genotype or serum CRP on the achievement of remission using anti-tumor necrosis factor alpha therapy.

CONCLUSIONS

CRP and CRP genotype differ between pediatric patients with CD and UC with a high inflammatory burden at diagnosis suggesting a worse prognosis. Additional evaluation of CRP in inflammatory bowel disease pathogenesis and natural history is now warranted.

Current relevance of pharmacogenetics in immunomodulation treatment for Crohn's disease

No drug therapy is completely risk free, and the costs associated with non-response and adverse effects can exceed the cost of the therapy. The ultimate goal of pharmacogenetic research is to find robust genetic predictors of drug response that enable the development of prospective genetic tests to reliably identify patients at risk of non-response or of developing an adverse effect prior to the drug being prescribed. Currently, thiopurine S-methyltransferase (TPMT) deficiency is the only pharmacogenetic factor that is prospectively assessed before azathioprine or 6-mercaptopurine immunomodulation is commenced in patients with Crohn's disease (CD). As yet no other inherited determinant of drug response has made the transition from bench to bedside for the management of this disease. In this review we summarize what is known about TPMT deficiency and explore whether there is evidence to support a role of other genetic polymorphisms in predicting the response of CD patients to thiopurine drugs, methotrexate, and anti-tumor necrosis factor α (TNFα) therapy.

Role of genetics in the diagnosis and prognosis of Crohn's disease

Considering epidemiological, genetic and immunological data, we can conclude that the inflammatory bowel diseases are heterogeneous disorders of multifactorial etiology in which hereditability and environment interact to produce the disease. It is probable that patients have a genetic predisposition for the development of the disease coupled with disturbances in immunoregulation. Several genes have been so far related to the diagnosis of Crohn's disease. Those genes are related to innate pattern recognition receptors, to epithelial barrier homeostasis and maintenance of epithelial barrier integrity, to autophagy and to lymphocyte differentiation. So far, the most strong and replicated associations with Crohn's disease have been done with NOD2, IL23R and ATG16L1 genes. Many genes have so far been implicated in prognosis of Crohn's disease and many attempts have been made to classify genetic profiles in Crohn's disease. CARD15 seems not only a susceptibility gene, but also a disease-modifier gene for Crohn's disease. Enriching our understanding on Crohn's disease genetics is important but when combining genetic data with functional data the outcome could be of major importance to clinicians.

Role of genetics in the diagnosis and prognosis of Crohn's disease

Considering the epidemiological, genetic and immunological data, we can conclude that the inflammatory bowel diseases are heterogeneous disorders of multifactorial etiology in which hereditability and environment interact to produce the disease. It is probable that patients have a genetic predisposition for the development of the disease coupled with disturbances in immunoregulation. Several genes have so far been related to the diagnosis of Crohn's disease. These genes are related to innate pattern recognition receptors, to epithelial barrier homeostasis and maintenance of epithelial barrier integrity, to autophagy and to lymphocyte differentiation. So far, the strongest and most replicated associations with Crohn's disease have been demonstrated with NOD2, IL23R and ATG16L1 genes. Many genes have so far been implicated in the prognosis of Crohn's disease and many attempts have been made for classification of genetic profiles in Crohn's disease. CARD15 seems to be not only a susceptibility gene, but also a disease-modifier gene for Crohn's disease. Enriching our understanding of Crohn's disease genetics is of value, but when combining genetic data with functional data the outcome could be of major importance to clinicians.

VEGF polymorphisms are associated with an increasing risk of developing renal cell carcinoma

PURPOSE

Vascular endothelial cell growth factor is studied in different malignant tumors as a key endothelial cell mitogen. Many single nucleotide polymorphisms in the VEGF gene have been described. We compared VEGF gene polymorphisms between a control group and a renal cancer group.

MATERIALS AND METHODS

This study was performed in 202 control, white, healthy blood donors (control group) and in 51 consecutive patients with renal cell carcinoma. We studied VEGF genotype polymorphisms at positions -2549, -460, -1154, +405 and +936 using polymerase chain restriction fragment length polymorphism, and looked for correlations with clinical data.

RESULTS

No association was found between VEGF gene polymorphism and renal cell carcinoma prognostic parameters. However, in contrast as observed for controls and other polymorphisms the patient group displayed a heterozygote excess (p = 0.0179, 35.9% more than that expected) at the -460 polymorphism. Comparing the control group and the renal cell carcinoma group we detected a significantly increased risk of renal cell carcinoma in subjects with the C-460T polymorphism. T carrier genotypes and the T allele increased the risk of renal cell carcinoma with an OR of 14.15 (95% CI 1.900-105.41, p = 0.0017) and 2.14 (95% CI 1.34-3.419, p = 0.0018), respectively. The genotype at the -2549 polymorphism exhibited a nonsignificant trend for increased risk but the D allele was significantly associated with increased risk (p = 0.0305).

CONCLUSIONS

Our results suggest that the -460 polymorphism is a risk factor for renal cancer. An individual screening test could be proposed for high risk populations.

Pharmacogenomics in the treatment of inflammatory bowel disease

In recent years, the benefits of early aggressive treatment paradigms for inflammatory bowel disease have emerged. Symptomatic improvement is no longer considered adequate; instead, the aim of treatment has become mucosal healing and altered natural history. Nonetheless, we still fail to achieve these end points in a large number of our patients. There are many reasons why patients fail to respond or develop toxicity when exposed to drugs used for inflammatory bowel disease, but genetic variation is likely to account for a significant proportion of this. Some examples, notably thiopurine methyltransferase polymorphism in thiopurine treatment, are already established in clinical practice. We present a review of the expanding literature in this field, highlighting many interesting developments in pharmacogenomics applied to inflammatory bowel disease and, where possible, providing guidance on the translation of these developments into clinical practice.

Relationships between disease activity and serum and fecal biomarkers in patients with Crohn's disease

BACKGROUND & AIMS

The quantitative relationships between instruments and assays that measure clinical, endoscopic, and biologic disease activity in patients with Crohn's disease are poorly characterized. This study evaluated the correlations between the Crohn's Disease Activity Index (CDAI), the Simple Endoscopic Score for Crohn's Disease (SES-CD), serum high-sensitivity C-reactive protein (hsCRP) (both phenotype and genotype) and interleukin-6 (IL-6), and fecal calprotectin and lactoferrin.

METHODS

A total of 164 patients with Crohn's disease undergoing colonoscopy were enrolled. The CDAI and SES-CD scores, serum hsCRP and IL-6, CRP and IL-6 genotypes, and fecal calprotectin and lactoferrin were measured.

RESULTS

There were no significant associations between the CDAI and SES-CD scores (Spearman rank correlation coefficient, 0.15) or between the CDAI scores and the serum concentrations of hsCRP and IL-6, or the fecal concentrations of calprotectin and lactoferrin. In contrast, the serum hsCRP and IL-6 concentrations and the fecal calprotectin and lactoferrin concentrations were significantly higher in patients with more severe endoscopic disease activity (SES-CD score > 7 points) (P < .001 for all comparisons). The CRP 717 mutant homozygote and heterozygote status was associated with significantly lower concentrations of hsCRP (P = .02). There was a trend toward higher hsCRP concentrations in the CRP 286 heterozygous adenine mutant-type mutant genotype, but this did not reach statistical significance.

CONCLUSIONS

Serum and fecal biomarker concentrations are associated with endoscopic but not clinical disease activity in patients with Crohn's disease. Stimulated hsCRP concentration is affected significantly by select genetic polymorphisms.

Pharmacogenetics of Crohn’s disease

The considerable interindividual differences in efficacy and side effects of commonly used medications in Crohn’s disease are partly owing to genetic polymorphisms. Many genetic variants have been studied in genes possibly involved in the metabolism or mechanism of action of therapeutic agents such as glucocorticosteroids, azathioprine/6-mercaptopurine, methotrexate, calcineurin inhibitors or anti-TNF agents. However, the only test translated into clinical practice is thiopurine S-methyltransferase (TPMT) genotyping for hematological toxicity of thiopurine treatment. To date, there are no other meaningful applications for pharmacogenomics in clinical practice of Crohn’s disease. In the future, designed therapeutic trials should possibly permit the development of predictive models including genotypic markers, such as that proposed for the clinical outcome after infliximab therapy, which includes an apoptotic pharmacogenetic index. The recent identification of new susceptibility genes provides additional candidate markers that have possible effects on the outcomes of therapies, and prioritizes new therapeutic targets, such as the IL-23 pathway. Futher innovative approaches might be relevant for the pharmacogenetic investigation of gene variants implied in innate immune pattern recognition and autophagy.

Anti-TNF antibodies: lessons from the past, roadmap for the future

Tumor necrosis factor alpha (TNF) is an important cell-signaling component of the immune system. Since its discovery over 20 years ago, much has been learned about its functions under normal and disease conditions. Nonclinical studies suggested a role for TNF in chronic immune-mediated inflammatory diseases, such as rheumatoid arthritis, Crohn's disease, and psoriasis, and therefore neutralizing monoclonal antibodies specific to human TNF were developed for clinical evaluation. Treatment with anti-TNF monoclonal antibodies (infliximab, adalimumab, and certolizumab pegol) has been shown to provide substantial benefit to patients through reductions in both localized and systemic expression of markers associated with inflammation. In addition, there are beneficial effects of anti-TNF treatment on markers of bone and cartilage turnover. Further exploration of changes in these markers and their correlation with clinical measures of efficacy will be required to allow accurate prediction of those patients most in need of these treatments. Both the clinical and commercial experience with these anti-TNF antibodies provide a wealth of information regarding their pharmacological effects in humans.

Assessment of endoscopic activity index and biological inflammatory markers in clinically active Crohn's disease with normal C-reactive protein serum level

BACKGROUND

Patients with clinically active Crohn's disease (CD), defined by a Crohn's Disease Activity Index (CDAI)>150, may have normal C-reactive protein (CRP) serum levels. In such cases, it is difficult to know whether these patients have really active disease or rather functional symptoms. This distinction is important to decide the most appropriate treatment. The aim of our work was to assess intestinal and colonic lesions in such patients and to look for biological markers potentially associated with endoscopic activity of the disease.

METHODS

We included 28 consecutive CD patients with CDAI>150 and a normal CRP level. These patients underwent a full colonoscopy with Crohn's Disease Endoscopy Index of Severity (CDEIS) calculation, fecal calprotectin, blood fibrinogen, acid alpha-1 glycoprotein, and erythrocyte sedimentation rate measurement. The Harvey-Bradshaw score was also calculated. Serum IL1 beta, IL6, IL8, sIL2R, and sTNFR2 were measured.

RESULTS

The median CDAI was 181 (151-485). Almost all (92.9%) these patients had endoscopic lesions, but the majority had only mild lesions (CDEIS<or=6). No correlation was found between CDEIS and any of the clinical or biological markers. However, all the patients with significant endoscopic lesions (defined by a CDEIS>6) had previous surgical intestinal resection and lesions involving the anastomosis.

CONCLUSIONS

Patients with elevated CDAI and normal CRP have only mild mucosal lesions of CD. Most significant lesions may be observed at the anastomosis and proximal to it in previously operated patients. None of the biological markers tested was associated with these endoscopic lesions.

Late-breaking news from the "4th International Meeting on Inflammatory Bowel Diseases" Capri, 2006

At the "4th International Meeting on Inflammatory Bowel Diseases: on the Way to New Therapies," Capri, 2006, genetics, bacteria-host interactions, immunomodulation, and tissue response were discussed deeply in order to understand, rationalize, and develop novel therapies. About genetics, the importance of a better understanding of the nature of known loci and of the putative associations was stressed. It was confirmed that genotype-phenotype associations in inflammatory bowel disease (IBD) have important clinical and therapeutic implications. The importance of the search for dominant bacterial antigens in chronic immune-mediated intestinal inflammation emerged, as well as knowledge of cellular and molecular mechanisms of bacterial-host interactions. It was discussed how innate and adaptive immunity signaling events can perpetuate chronic inflammation. Signal transduction pathways provide an intracellular mechanism by which cells respond and adapt to environmental stress. The identification of these signals have led to a greater understanding of the pathogenesis of IBD and pointed to potential therapeutic targets. It was shown that immune homeostasis is lost in IBD, resulting in a complex tissue response involving the action of immune and nonimmune cells. The nonimmune tissue response in IBD could be regarded as a new target for control of chronic intestinal inflammation. The changing role of biotherapy in IBD was widely discussed and in particular the anti-TNF-alpha monoclonal antibodies. Granulocyte-colony stimulating factor (GM-CSF) and stem cells therapies were also discussed. The risk-to-benefit ratio of the novel therapies was analyzed in detail. Finally, future directions for basic science and the unmet needs for clinical practice were presented.

Adalimumab in patients with Crohn's disease--safety and efficacy in an open-label single centre study

AIM

To evaluate the efficacy and safety of adalimumab, a human antitumour necrosis factor-alpha antibody, in induction and maintenance of remission in patients with Crohn's disease either refractory or intolerant to infliximab in a single centre cohort.

METHODS

Sixteen Crohn's disease patients received 160 mg adalimumab subcutaneously in week 0, followed by 80 mg every other week. Clinical response was assessed based on Crohn's disease activity index and laboratory parameters (leukocyte count, C-reactive protein). In all patients genotyping for CARD15 variants and the +1059G/C polymorphism in the C-reactive protein gene was performed.

RESULTS

In 10 of 16 patients (63%) treated with adalimumab, remission (CDAI score <150) was induced for at least 8 weeks independent of CARD15 or +1059G/C CRP status. In six of these 10 patients ongoing remission is observed now for more than 24 weeks. Adalimumab significantly decreased C-reactive protein serum levels and Crohn's disease activity index. There was one serious complication (fungal pneumonia). Six patients intermittently developed minor dermatological problems resolving after topical therapy. Otherwise, treatment was generally well tolerated.

CONCLUSION

Adalimumab can induce and maintain remission in patients with moderate to severe Crohn's disease intolerant or refractory to infliximab. Further experience from larger cohorts is required to evaluate dose regimen and safety profiles in Crohn's disease therapy.

Polymorphism in IgG Fc receptor gene FCGR3A and response to infliximab in Crohn's disease: a subanalysis of the ACCENT I study

Recently, it has been shown that FCGR3A-158 gene polymorphism is associated with biological and possibly clinical response to infliximab in Crohn's disease. We further assessed this association in a subset of 344 patients from the large and well-defined cohort of 573 patients with Crohn's disease from the ACCENT I study. No association could be observed between FCGR3A-158 gene polymorphism and the clinical response to infliximab, which was primarily defined as a decrease of >or=70 points in the Crohn's disease activity index or clinical remission (Crohn's disease activity index <150). We did, however, confirm a trend towards a greater decrease in C-reactive protein after infliximab in V/V homozygotes as compared with V/F heterozygotes and F/F homozygotes (-79.4, -76.5, and -64.3%, respectively, at week 6; P=0.085; one-tailed P=0.043). This finding has no immediate clinical impact but may enhance the understanding of the complex mechanisms of action of anti-tumor necrosis factor agents in Crohn's disease.

Potential role of pharmacogenetics in anti-TNF treatment of rheumatoid arthritis and Crohn's disease

Etanercept, infliximab and adalimumab have shown clinical benefit in immune-mediated inflammatory diseases; however, the outcome of treatment with these tumour-necrosis factor inhibitors remains insufficient in approximately 40-60% and approximately 25-40% of individuals with rheumatoid arthritis and Crohn's disease, respectively. Moreover, their use is accompanied by adverse events and unintentional immune suppression. Pharmacogenetics has the potential to increase efficacy and ameliorate adverse events and immune suppression, and its application might be of clinical benefit for patients with rheumatoid arthritis and Crohn's disease. Pharmacogenetic studies have shown associations between single nucleotide polymorphisms in genes encoding enzymes related to the pharmacodynamics of these drugs and treatment outcome. As we discuss here, replication and prospective validation are warranted before pharmacogenetics can be used in clinical practice.

The +1059G/C polymorphism in the C-reactive protein (CRP) gene is associated with involvement of the terminal ileum and decreased serum CRP levels in patients with Crohn's disease

BACKGROUND

Serum C-reactive protein (CRP) levels influence the response to anti-tumour necrosis factor (TNF) therapies.

AIM

To analyse the influence of the +1059G/C CRP polymorphism on CRP serum levels and disease susceptibility in patients with Crohn's disease (CD).

METHODS

Using restriction fragment length polymorphism (RFLP) analysis, genomic DNA from 241 CD patients and 199 unrelated controls was analysed for the +1059G/C substitution in the CRP gene and the common caspase-activation recruitment domain 15 (CARD15) variants.

RESULTS

Homozygous C/C carriers were detected only among CD patients (P = 0.066). Patients with ileal involvement (L1 and L3 phenotype) were found in only 58.4% of patients with the wildtype G/G genotype but in 88.2% of the heterozygous G/C carriers (OR 5.26; 95% CI 1.19-23.92) and four of the five C/C homozygous carriers (80%; OR 4.55; 95% CI 1.64-16.67; P = 0.008 for hetero- and homozygous carriers vs. wildtype) which was independent of the presence of CARD15 variants. Increased CD activity was associated with increased CRP serum levels (P < 0.005). For Crohn's disease activity index (CDAI) < 150, C/C homozygosity for the +1059 G/C polymorphism was associated with significantly lower CRP serum levels (P < 0.01).

CONCLUSIONS

The C allele of the CRP +1059G/C polymorphism is associated with decreased serum CRP levels and increased likelihood of disease involvement of the terminal ileum in CD patients.

Genetic variants and the risk of Crohn's disease: what does it mean for future disease management?

Genetic research in inflammatory bowel disease, especially in Crohn's disease, has made significant progress during recent years. There have been > 10 total genome scans that have been performed, and susceptibility loci on several chromosomes have been identified. Together with candidate gene studies, these scans have led to the identification of several susceptibility genes, with CARD15 being the most important. These genetic data have already provided important insights into the pathophysiology of inflammatory bowel disease and are stimulating future research. On the other hand, genotype-phenotype associations have illustrated the heterogenic nature of the disease. Although the clinical application of this knowledge is so far limited, there is significant optimism that an individual management of patients based on genetic data will be possible in the near future.

Protein therapeutics: new applications for pharmacogenetics

Pharmacogenetic studies have traditionally focused on genes involved in processes that affect the pharmacokinetics of small-molecule drugs, such as drug metabolism. However, attention is shifting to the effects of genetic variations in drug targets and associated pathway components on drug responses. We describe how these variations are important for understanding differences in responses to the growing number of protein therapeutics that are entering clinical practice. Pharmacogenetic studies of these drugs are surveyed, and issues important to the success of such endeavours are discussed. As novel protein therapeutics are introduced, we anticipate that the use of pharmacogenetics will assume a key role in their development and clinical application.