Serological markers for prediction of response to anti-tumor necrosis factor treatment in Crohn's disease

The utility of biomarkers in the diagnosis and therapy of inflammatory bowel disease

Fecal and serologic biomarkers can be used in the diagnosis and management of inflammatory bowel disease (IBD). Fecal markers such as calprotectin and lactoferrin have been studied for their ability to identify patients with IBD, assess disease activity, and predict relapse. Antibodies against Saccharomyces cerevisiae and perinuclear antineutrophil cytoplasmic proteins have been used in diagnosis of IBD, to distinguish Crohn's disease (CD) from ulcerative colitis, and to predict the risk of complications of CD. Tests for C-reactive protein and erythrocyte sedimentation rate have been used to assess inflammatory processes and predict the course of IBD progression. Levels of drug metabolites and antibodies against therapeutic agents might be measured to determine why patients do not respond to therapy and to select alternative treatments. This review addresses the potential for biomarker assays to improve treatment strategies and challenges to their use and development.

Serologic antiglycan antibodies in inflammatory bowel disease

At diagnosis, the clinical presentation of both entities of inflammatory bowel disease (IBD), Crohn's disease (CD) and ulcerative colitis (UC), can be highly heterogeneous, leading to a delay in correct identification or differentiation between CD and UC in a subgroup of patients. In addition, the natural history of IBD patients is strikingly variable. During the life of a CD patient, in the majority of instances, stricturing or perforating complications occur, leading to surgery. Serologic antiglycan antibodies directed against various microbial carbohydrate epitopes are useful in differentiation of CD vs. UC and are a promising tool for identification of CD patients at risk for rapid progression and need for surgical intervention. Instruments for prediction of CD behavior are critical, as the use of immunomodulators and/or biologicals early in the disease course might be justified for patients with a high hazard for complicated disease behavior.

The London Position Statement of the World Congress of Gastroenterology on Biological Therapy for IBD with the European Crohn's and Colitis Organization: when to start, when to stop, which drug to choose, and how to predict response?

The advent of biological therapy has revolutionized inflammatory bowel disease (IBD) care. Nonetheless, not all patients require biological therapy. Selection of patients depends on clinical characteristics, previous response to other medical therapy, and comorbid conditions. Availability, reimbursement guidelines, and patient preferences guide the choice of first-line biological therapy for luminal Crohn's disease (CD). Infliximab (IFX) has the most extensive clinical trial data, but other biological agents (adalimumab (ADA), certolizumab pegol (CZP), and natalizumab (NAT)) appear to have similar benefits in CD. Steroid-refractory, steroid-dependent, or complex fistulizing CD are indications for starting biological therapy, after surgical drainage of any sepsis. For fistulizing CD, the efficacy of IFX for inducing fistula closure is best documented. Unique risks of NAT account for its labeling as a second-line biological agent in some countries. Patients who respond to induction therapy benefit from systematic re-treatment. The combination of IFX with azathioprine is better than monotherapy for induction of remission and mucosal healing up to 1 year in patients who are naïve to both agents. Whether this applies to other agents remains unknown. IFX is also effective for treatment-refractory, moderate, or severely active ulcerative colitis. Patients who have a diminished or loss of response to anti-tumor necrosis factor (TNF) therapy may respond to dose adjustment of the same agent or switching to another agent. Careful consideration should be given to the reasons for loss of response. There are insufficient data to make recommendations on when to stop anti-TNF therapy. Preliminary evidence suggests that a substantial proportion of patients in clinical remission for >1 year, without signs of active inflammation can remain in remission after stopping treatment.

Diagnosis and assessment of Crohn's disease: the present and the future

Diagnosis of Crohn's disease (CD) is often challenging and requires the utmost precision and perseverance in defining location, extent, severity and type of disease (inflammatory vs stricturing/penetrating), as well as in excluding septic complications and extraintestinal manifestations. Endoscopy and histology remain, as of today, the best tests for initial diagnosis of CD. Increasingly important roles are played by imaging techniques (small bowel MRI, computed tomographic enterography and intestinal ultrasound) and noninvasive markers of disease such as fecal calprotectin and specific autoantibodies. Here, we will review the main tools presently available to make the initial diagnosis of intestinal and perianal CD, to evaluate the response to treatment and to diagnose disease recurrence after surgery. Finally, we will discuss some of the future diagnostic challenges in CD.

Disease activity, ANCA, and IL23R genotype status determine early response to infliximab in patients with ulcerative colitis

OBJECTIVES

We analyzed the efficacy and safety of the antitumor necrosis factor-alpha antibody infliximab (IFX) for induction therapy in patients with moderate-to-severe ulcerative colitis (UC) in a large single-center cohort.

METHODS

A total of 90 UC patients treated with IFX for 14 weeks were analyzed retrospectively. Colitis activity index (CAI) and markers of inflammation were measured during IFX induction therapy. Genotyping for UC-associated variants in the IL23R gene and in the IL2/IL21 region was performed.

RESULTS

At week 2 (after the first IFX infusion), 64.1% of IFX-treated patients had clinical response to IFX and 52.6% were in remission. At week 14 (after three infusions), 61.0% showed clinical response and 52.5% were in remission. The mean CAI decreased significantly from 10.4 points at week 0 to 5.1 at week 2 (P<0.001), to 4.4 at week 6 (P<0.001), and to 5.0 at week 14 (P<0.001). Similarly, IFX therapy significantly decreased C-reactive protein levels and leukocyte counts (P=0.01 and P=0.001 at week 2 and week 0, respectively). Multivariate regression analysis identified high CAI before IFX therapy (P=0.01) and negative antineutrophil cytoplasmatic autoantibody (ANCA) status (P=0.01) as independent positive predictors for response to IFX. Homozygous carriers of inflammatory bowel disease (IBD) risk-increasing IL23R variants were more likely to respond to IFX than were homozygous carriers of IBD risk-decreasing IL23R variants (74.1 vs. 34.6%; P=0.001). No serious adverse IFX-related events requiring hospitalization were recorded.

CONCLUSIONS

Our findings suggest that IFX therapy is safe and effective in patients with moderate-to-severe UC. A high CAI before IFX therapy, ANCA seronegativity, and the IL23R genotype were predictors of early response to IFX.

Mucosal biomarkers in inflammatory bowel disease: Key pathogenic players or disease predictors?

Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders of the bowel, including ulcerative colitis and Crohn’s disease. A single etiology has not been identified, but rather the pathogenesis of IBD is very complex and involves several major and minor contributors, employing different inflammatory pathways which have different roles in different patients. Although new and powerful medical treatments are available, many are biological drugs or immunosuppressants, which are associated with significant side effects and elevated costs. As a result, the need for predicting disease course and response to therapy is essential. Major attempts have been made at identifying clinical characteristics, concurrent medical therapy, and serological and genetic markers as predictors of response to biological agents. Only few reports exist on how mucosal/tissue markers are able to predict clinical behavior of the disease or its response to therapy. The aim of this paper therefore is to review the little information available regarding tissue markers as predictors of response to therapy, and reevaluate the role of tissue factors associated with disease severity, which can eventually be ranked as “tissue factor predictors”. Five main categories are assessed, including mucosal cytokines and chemokines, adhesion molecules and markers of activation, immune and non-immune cells, and other mucosal components. Improvement in the design and specificity of clinical studies are mandatory to be able to classify tissue markers as predictors of disease course and response to specific therapy, obtain the goal of achieving “personalized pathogenesis-oriented therapy” in IBD.

Future biologic targets for IBD: potentials and pitfalls

The treatment of patients with IBD has evolved towards biologic therapy, which seeks to target specific immune and biochemical abnormalities at the molecular and cellular level. Multiple genes have been associated with susceptibility to IBD, and many of these can be linked to alterations in immune pathways. These immune pathways provide avenues for understanding the pathogenesis of IBD and suggest future drug targets, such as the IL-12-IL-23 pathway. In addition, failed therapeutic drug trials can provide valuable information about pitfalls in study design, drug delivery and disease activity assessment. Future biologic drug development will benefit from the early identification of subsets of patients who are most likely to respond to therapy by use of biological markers of genetic susceptibility or immunologic susceptibility.

Uveitis Seroreactivity to Candidate pANCA Antigens: Mycobacterial HupB and Histone H1(69-171)

PURPOSE

Certain uveitis patients express the disease-marker antibody pANCA. Histone H1 (H1) and mycobacterial HupB (HupB) are recently identified candidate pANCA antigens. This study addresses the hypothesis that H1 and HupB are targets of disease-associated seroreactivity in pANCA+ uveitis.

METHODS

Sera from 293 uveitis patients were categorized for pANCA activity. H1(69-171) and HupB recombinant proteins were used as antigenic targets in ELISA studies. Selected sera were analyzed for reactivity by Western blot.

RESULTS

Seroreactivities to ANCA, H1(69-171), and HupB were frequently detected in uveitis patients. No significant relationship existed between the level of ANCA antibody and reactivity to either recombinant antigen. There was, however, a significant, positive correlation between H1(69-171) and HupB seroreactivities.

CONCLUSIONS

Correlation between H1(69-171) and HupB reactivities suggests the presence of a shared dominant epitope, which is recognized by antibodies in a substantial number of uveitis patients. Seroreactivities to ANCA and HupB/H1 are independent immunologic markers that may identify biologically distinctive subsets of uveitis.

Antiglycan antibodies as serological markers in the differential diagnosis of inflammatory bowel disease

BACKGROUND

The objective of the study was to evaluate the diagnostic accuracy of recently developed antiglycan serological tests in clinical practice for the diagnosis of Crohn's disease.

METHODS

This study was a cohort analysis of both clinical and biochemical parameters of patients with diagnosed inflammatory bowel disease compared with those in a control population. Antiglycan antibodies were determined using commercially available enzyme immunoassays. The setting was the outpatient unit of the gastroenterology department of a large, tertiary-care referral academic hospital. Participants were 214 consecutive patients, enrolled over a 5-month period, including 116 with Crohn's disease and 53 with ulcerative colitis, as well as 45 with other gastrointestinal diseases and 51 healthy controls.

RESULTS

Anti-Saccharomyces cerevisiae antibodies showed the best performance (54% sensitivity and 88%-95% specificity for Crohn's disease). Among patients with negative anti-Saccharomyces antibodies, 19 (34%) had high titers of at least another tested antiglycan antibody. Anti-Saccharomyces and anti-laminaribioside antibodies were associated with disease involving the small bowel and with penetrating or stricturing phenotype. Anti-laminaribioside was significantly higher in patients with a familial history of inflammatory bowel disease.

CONCLUSIONS

The new proposed serological markers are significantly associated with Crohn's disease, with low sensitivity but good specificity. About one third of anti-Saccharomyces-negative patients may be positive for at least 1 of those markers. Antiglycan antibodies appear to be associated with characteristic localization and phenotype of the disease.

Detection of antisynthetic mannoside antibodies (ASigmaMA) reveals heterogeneity in the ASCA response of Crohn's disease patients and contributes to differential diagnosis, stratification, and prediction

OBJECTIVES

Anti-S. cerevisiae mannan antibodies (ASCA) are human antibodies associated with Crohn's disease (CD) reacting with Saccharomyces cerevisiae (S. cerevisiae) mannan polymer. As mannan is a complex and variable repertoire of oligomannoses acting as epitopes, we chemically synthesized (Sigma) two major oligomannose epitopes, Man alpha-1,3 Man alpha-1,2 Man (SigmaMan3) and Man alpha-1,3 Man alpha-1,2 Man alpha-1,2 Man (SigmaMan4), and then explored how antisynthetic mannoside antibodies (ASigmaMA) compare with ASCA as markers of CD.

METHODS

The study involved different cohorts of CD and ulcerative colitis (UC) patients and healthy controls who had been studied previously in several medical centers in Europe, the United States, and North Africa to determine the clinical value of ASCA in terms of differential diagnosis, evolution of indeterminate colitis (IC), and serotype-phenotype correlations. The comparison of ASigmaMA and ASCA included a total of 1,365 subjects: 772 CD, 261 UC, 43 IC, and 289 controls.

RESULTS

The specificity of ASigmaMA was similar to that of ASCA (89% vs 93%), although the sensitivity was lower (38% vs 55%). Unexpectedly, 24% of the CD patients who were negative for ASCA and/or other CD-associated serologic markers were positive for ASigmaMA. ASigmaMA were associated with colonic involvement in CD (odds ratio [OR] 1.609, 95% confidence interval [CI] 1.033-2.506, P = 0.03) and were 100% predictive of CD in patients with IC.

CONCLUSIONS

ASigmaMA reveal the heterogeneity of the antioligomannose antibody response in CD patients and increase the sensitivity of CD diagnosis when combined with ASCA. The subset of ASCA-negative CD patients diagnosed by ASigmaMA had preferentially a colonic involvement, which confirms the high predictive value of ASigmaMA for determining IC evolution toward CD.

Serologic markers in inflammatory bowel disease: tools for better diagnosis and disease stratification

In the last decade, new serologic markers have been identified, and attempts to delineate their potential roles in inflammatory bowel disease diagnosis, determination of prognosis and identification of apparently healthy subjects at risk have significantly increased our knowledge. In this review, the major serologic markers will be described, focusing on their common features as a group. It is predicted that within the next 5 years, panels of antibodies will prove to have a significant impact on disease diagnosis and stratification, as well as on the identification of populations at risk and the prediction of response to treatment. Thus, it is expected that they will become useful clinical tools that will enable an improved, 'tailored' approach to inflammatory bowel disease patients.

IBD serological panels: facts and perspectives

Beyond a defective innate immune response in inflammatory bowel disease (IBD), an increased immunological response toward microbial and self antigens has been intrinsically linked to the pathogenesis of such common immunopathologies of the gut. Mounting evidence indicates that increased seroreactivity toward certain antigens are a predictive and quantitative heritable trait, including the anti-Saccharomyces cerevisiae antibody (ASCA). Consistently, Candida albicans and Crohn's disease-associated NOD2 mutations have been recently identified as immunogen and genetic determinants for ASCA, respectively. In clinical practice, current panels of serological markers are not recommended for diagnosis, stratifying, and monitoring IBD. Therefore, prospective studies and highly sensitive serological panels of markers are eagerly awaited before guiding clinical decisions. Better understanding of the serological response in IBD might also provide new insights into their epidemiology and pathophysiology.

Interleukin-18 is increased only in a minority of patients with active Crohn's disease

BACKGROUND AND AIMS

It has been suggested that Crohn's Disease (CD) is associated with an elevated T helper 1 response as manifested by increased production of interleukin-18 (IL-18). Local concentrations of neutralizing IL-18 binding proteins (IL-18 bp) may counteract biological functions of mature IL-18 in mucosal inflammation. Therefore, we investigated the IL-18/IL-18 bp system in a large group of patients with active inflammatory bowel disease (IBD) to identify patients that could respond theoretically to IL-18 neutralizing treatment strategies.

PATIENT/METHODS

IL-18 and IL-18 bp messenger RNA (mRNA) expression in colonic mucosa from patients with active CD (n = 72), active ulcerative colitis (UC; n = 32), and non-IBD controls (infectious colitis or diverticulitis; n = 19) and normal, non-diseased controls (n = 20) were measured by reverse-transcribed real-time polymerase chain reaction. Mature IL-18 protein and IL-18 bp expression in inflamed mucosa were assessed by Western blotting.

RESULTS/FINDINGS

Although IL-18 mRNA was increased in some patients with CD, the increase was not statistically significant. Densitometric evaluation of IL-18/alpha-actin ratio in patients with active CD (n = 20) and patients with UC (n = 10) demonstrated an increased ratio of IL-18 protein in CD when compared to UC (1.04 vs 0.72 [median]). On closer inspections, only 7/20 CD patients had an increased IL-18 protein expression in inflamed areas compared to noninflamed mucosa.

INTERPRETATION/CONCLUSION

IL-18 expression in active CD is heterogeneous, only a minority of patients expresses elevated levels. Further treatment strategies targeting IL-18 expression in active CD should be concentrated on this subgroup of patients.

Seroreactivity to microbial components in Crohn's disease is associated with ileal involvement, noninflammatory disease behavior and NOD2/CARD15 genotype, but not with risk for surgery in a Hungarian cohort of IBD patients

BACKGROUND

Antibodies directed against Saccharomyces cerevisiae (ASCA), perinuclear components of neutrophils (pANCA), and porin protein C of Escherichia coli (anti-OmpC) are reported to be associated with disease phenotype and may be of diagnostic importance in inflammatory bowel disease (IBD). Since limited data are available from Eastern Europe, we assessed the above antibodies in Hungarian IBD patients.

METHODS

In all, 653 well-characterized, unrelated consecutive IBD patients (Crohn's disease [CD]: 558, m/f: 263/295, duration: 8.1 +/- 10.7 years; ulcerative colitis [UC]: 95, m/f: 44/51, duration: 8.9 +/- 9.8 years) and 100 healthy subjects were investigated. Sera were assayed for anti-Omp and ASCA by enzyme-linked immunosorbent assay (ELISA) and ANCA by indirect immunofluorescence assay (IIF). TLR4 and NOD2/CARD15 variants were tested by polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP). Detailed clinical phenotypes were determined by reviewing the medical charts.

RESULTS

Anti-Omp, ASCA, and atypical pANCA antibodies were present in 31.2%, 59.3%, and 13.8% of CD, 24.2%, 13.7%, and 48.5% of UC patients, and in 20%, 16%, and 5.6% of controls, respectively. ASCA and anti-Omp positivity were associated with increased risk for CD (odds ratio [OR](ASCA) = 7.65, 95% confidence interval [CI]: 4.37-13.4; OR(Omp) = 1.81, 95% CI: 1.08-3.05). In a logistic regression analysis, anti-Omp and ASCA were independently associated with ileal and noninflammatory disease, but not with a risk for surgery or response to steroids or infliximab. A serology dosage effect was also observed. ASCA and anti-Omp antibodies were associated with NOD2/CARD15, in addition to a gene dosage effect. No associations were found in UC.

CONCLUSIONS

Serological markers were useful in the differentiation between CD and UC in an Eastern European IBD cohort. Reactivity to microbial components was associated with disease phenotype and NOD2/CARD15 genotype, further supporting the role of altered microbial sensing in the pathogenesis of CD.

American gastroenterological association consensus development conference on the use of biologics in the treatment of inflammatory bowel disease, June 21-23, 2006

The American Gastroenterological Association (AGA) convened a panel of gastroenterologists expert in the area of inflammatory bowel disease (IBD) that developed this consensus statement based on expert presentations of current scientific knowledge about IBD and through subsequent group discussion. This statement reflects the panel's assessment of medical knowledge available when written. Thus, readers should view this statement in the context of data that will accumulate after its creation. The opinions, conclusions, and recommendations expressed in this report are those of the consensus panel members and may or may not reflect the official opinion of the American Gastroenterological Association Institute. The conference upon which this report is based was funded through an unrestricted educational grant from Abbott Laboratories. Abbott Laboratories representatives did not attend the conference, nor did they participate in any way in the development of this report.

[Relevance of serologic studies in inflammatory bowel diseases]

The panel of serologic markers for inflammatory bowel diseases (IBDs) is rapidly expanding. Although anti- Saccharomyces cerevisiae antibodies (ASCA) and atypical perinuclear antineutrophil cytoplasmic antibodies (atypical P-ANCA) remain the most widely investigated, an increasing amount of experimental data is available on newly discovered antibodies directed against various microbial antigens. Such antibodies include anti-OmpC (outer membrane porin C), anti- Pseudomonas fluorescens (anti-I2) and antiglycan antibodies (anti-laminaribioside carbohydrate antibody [ALCA]), anti-chitobioside carbohydrate antibody [ACCA]), anti-mannobioside carbohydrate antibody [AMCA]) and anti-CBir1; this latter is the first bacterial antigen to induce colitis in animal models of IBD and also leads to a pathological immune response in IBD patients (anti-flagellin antibody). The role of assessment of various antibodies in the current diagnostic algorithm of IBD is rather questionable due to their limited sensitivity. In contrast, the association of serologic markers with disease behavior and phenotype is getting more into the focus of interest. An increasing number of observations confirm that patients with Crohn's disease expressing multiple serologic markers at high titers are more likely to have complicated small bowel disease (e.g. stricture and/or perforation) and are at higher risk for surgery than those without, or with low titer of antibodies. Creating homogenous disease sub-groups based on serologic response may help develop more standardized therapeutic approaches and may help in a better understanding of the pathomechanism of IBD. Further prospective clinical studies are needed to establish the clinical role of serologic tests in IBD.

Utility of serological markers in inflammatory bowel diseases: gadget or magic?

The panel of serologic markers for inflammatory bowel diseases (IBD) is rapidly expanding. Although anti-Saccharomyces cerevisiae antibodies (ASCA) and atypical perinuclear antineutrophil cytoplasmic antibodies (P-ANCA) remain the most widely investigated, an increasing amount of experimental data is available on newly discovered antibodies directed against various microbial antigens. The role of the assessment of various antibodies in the current IBD diagnostic algorithm is often questionable due to their limited sensitivity. In contrast, the association of serologic markers with disease behavior and phenotype is becoming increasingly well-established. An increasing number of observations confirms that patients with Crohn's disease expressing multiple serologic markers at high titers are more likely to have complicated small bowel disease (e.g. stricture and/or perforation) and are at higher risk for surgery than those without, or with low titers of antibodies. Creating homogenous disease sub-groups based on serologic response may help develop more standardized therapeutic approaches and may help in a better understanding of the pathomechanism of IBD. Further prospective clinical studies are needed to establish the clinical role of serologic tests in IBD.

Predictive model for the outcome of infliximab therapy in Crohn's disease based on apoptotic pharmacogenetic index and clinical predictors

BACKGROUND

Infliximab (IFX) is an effective therapy for refractory luminal and fistulizing Crohn's disease (CD). Predictors of response could improve selection of patients with a higher probability of favorable outcomes and could improve the safety profile. We aimed to develop a predictive model for the response to infliximab in CD.

METHODS

Genetic and clinical data collected in a previous pharmacogenetic study of apoptosis genes were analyzed using SAS Enterprise miner modeling software and SPSS 12.0. We proposed a novel apoptotic pharmacogenetic index (API) with a score ranging from 0 (low apoptotic response) to 3 (high apoptotic response) and subsequently developed a decision tree model.

RESULTS

Response and remission rates significantly increased with API score (P = 0.005 in the group of patients with luminal CD, P = 0.02 in the group of patients with fistulizing CD). Patients with an API < or = 1 (n = 59) had the lowest response and remission rates in both the luminal CD (50% and 39.5%, respectively) and fistulizing CD (61.9% and 28.6%, respectively) groups, compared to those with an API of 2 (n = 158), whose response and remission rates were 73.8% and 56.1%, respectively, in the luminal CD group and 85.7% and 44.9%, respectively, in the fistulizing CD group; and those with an API of 3 (n = 10), whose response and remission rates were 100% and 85.7%, respectively, in the luminal CD group and 100% and 0% in the fistulizing CD group. Response in patients with an API < or = 1 was significantly influenced by concurrent azathioprine therapy in the luminal CD (21.4% versus 78.9%, P < 0.001) and in the fistulizing CD (46.6% versus 100%, P = 0.04) groups. In patients with an API of 2, we saw an interaction with age older than 40 years and location of disease (response 52.2% versus 83.9%, P = 0.008) in the luminal CD group and with baseline CRP greater than 5 mg/L (73.9% versus 93.9%, P = 0.04) in the fistulizing CD group.

CONCLUSIONS

From our newly proposed apoptotic pharmacogenetic index and clinical predictors, we developed a model for prediction of low, medium, and high responses to the first infusion of IFX in patients with CD. Further studies are needed to confirm the hypothesis generated by our study.

Predictors of early response to infliximab in patients with ulcerative colitis

BACKGROUND

Our objective is to report the outcome of infliximab (IFX) in ulcerative colitis (UC) patients from a single center and to identify predictors of early clinical response.

METHODS

The first 100 UC patients (45 female; median age, 37.9 years) who received IFX at a single center were included. Eighty-four patients received 5 mg/kg IFX, and 37 patients received a 3-dose IFX induction at weeks 0, 2, and 6. The Mayo endoscopic subscore, assessed by sigmoidoscopy before inclusion, was 1, 2, and 3 in 5%, 52%, and 43% of patients, respectively. Sixty percent had pancolitis, 63% were on concomitant immunosuppressive therapy, 9% were active smokers, 64% had C-reactive protein > or =5 mg/dL, and 44% were pANCA+/ASCA-. Five patients received IFX because of severe acute colitis refractory to intravenous corticosteroids.

RESULTS

Early complete and partial clinical responses were observed in 41% and 24% of patients. Patients with early clinical response were significantly younger than nonresponders (median age, 35.7 versus 41.6 years, P = 0.041). Patients who were pANCA+/ASCA- had a significantly lower early clinical response (55% versus 76%; odds ratio [OR] = 0.40 (0.16-0.99), P = 0.049). Concomitant immunosuppressive therapy and the use of an IFX induction scheme did not influence early clinical response. Only 1 of 5 patients who received IFX for acute steroid-refractory colitis required colectomy within 2 months.

CONCLUSIONS

IFX is an efficient therapy in UC, as shown by 65% early clinical response. A pANCA+/ASCA- serotype and an older age at first IFX infusion are associated with a suboptimal early clinical response.

Predictive value of mucosal TNF-alpha transcripts in steroid-refractory Crohn's disease patients receiving intensive immunosuppressive therapy

BACKGROUND

Concentrations of proinflammatory cytokines are increased in the intestinal mucosa of patients with active Crohn's disease (CD). In a prospective study we investigated whether cytokines can predict long-term remission (>6 months) in patients with steroid-refractory CD receiving treatment with infliximab or cyclophosphamide, followed by azathioprine or methotrexate.

METHODS

Cytokine transcripts were quantified using real-time polymerase chain reaction (PCR) in mucosal biopsies from 19 patients with active, steroid-refractory CD before and 8 weeks after initiation of therapy. Patients were treated with cyclophosphamide (monthly treatment of 750 mg cyclophosphamide intravenously) or infliximab (5 mg/kg body weight) and were followed until relapse of the disease. Statistical analysis was performed to identify predictive factors to discriminate between patients with or without long-term remission.

RESULTS

Seventeen out of 19 patients achieved remission of the disease, two patients were nonresponders, while six out of 17 patients exhibited an early recurrence. Pretreatment TNF-alpha, IL-18, MRP-14, and IL-8 transcripts were significantly correlated with long-term remission. While several cytokines, most importantly MMP-1, determined after 8 weeks were able to predict patients achieving long-term remission, only a decrease of TNF-alpha levels after 8 weeks was predictive. Overall, statistical analysis identified lower pretreatment TNF-alpha levels as the strongest predictor of long-term remission among baseline variables.

CONCLUSIONS

Quantification of mucosal TNF-alpha transcripts prior to therapy allows identification of patients achieving long-term remission upon immunosuppression with infliximab or cyclophosphamide. Real-time PCR might have considerable potential in the analysis of disease activity and subsequent clinical management of patients with immunosuppressive therapies.

Infliximab use in luminal Crohn's disease

Infliximab has been available in the United States and Europe for more than 6 years, and its use has revolutionized the care of patients who have CD. It is used effectively for both the induction and maintenance of remission in patients who have CD and is efficacious in patients who have steroid-dependent/refractory CD and those who have fistulizing CD. Clinical trials and practice have shown infliximab to be safe, effective, and generally well tolerated. The ACCENT I and ACCENT II trials defined the best dosing and schedule regimens for its administration. With up to 30% of patients not responding to infliximab therapy, much attention has been devoted to identifying risk factors that could allow optimization of response rates. Parsi and colleagues and Arnott and colleagues demonstrated that nonsmoking and the concurrent use of immunomodulators are predictors of response to infliximab. Research has also focused on identifying biologic and immunologic markers that may correlate with response to infliximab. To date, N0D2/CARD15, anti-Saccharomyces cerevisiae antibody (ASCA), and antineutrophil cytoplasmic antibody (ANCA) have not been shown to be predictive of outcome with infliximab treatment for CD. Gene polymorphisms also are being studies with the hope that knowing the patient's genotype may help predict the course or severity of the disease, including the presence of extraintestinal manifestations, response to treatments, and susceptibility to toxicities. No single variable, however, has been consistently demonstrated to be a predictor of response to infliximab. The formation of ATIs in a small number of patients creates a clinical dilemma. ATIs have been associated with an attenuated response or loss of response to the medication over time and the development of both acute and delayed infusion reactions that occasionally are severe enough to lead to discontinuation of the medication. In such patients physicians are often left to ponder what therapy to try next. Adalimumab, a fully human monoclonal antibody used for treating rheumatologic conditions, has been investigated as an alternate treatment for patients who have CD who, after initially responding to infliximab, experience intolerance or loss of efficacy. Two studies have examined the use of adalimumab in patients who have active CD who had lost response to or developed intolerance to infliximab. In both these studies adalimumab was well tolerated and seemed to be a clinically beneficial option for such patients. Confirmation of these findings with ongoing randomized, double-blind, placebo-controlled trials is needed, however. The limits of conventional treatment for CD can be seen as a positive evolutionary force favoring the development and use of advanced therapies. The acceptance of antimetabolites began with data published a quarter-century ago and became robust in the past 5 to 10 years. Biologic therapy has become the standard of care at a far faster rate. The success seen with infliximab has broadened the acceptance of biologic therapy among professional peers, patients, and pharmaceutical developers. The lessons learned in the years since infliximab's arrival show the importance of long-term data in revealing important toxicities and best practices for maintenance. Tempered by this experience, the short cycle from concept to drug production possible with biologic therapies should bring even more advanced treatments to patients quickly while investigators work to find a cure.

Serologic markers in inflammatory bowel disease

Inflammatory bowel disease (IBD) is an enduring disease involving mostly young people, with symptoms of bloody diarrhea and abdominal cramps. Several antibodies have been associated with IBD, the 2 most comprehensively studied being autoantibodies to neutrophils (atypical perinuclear anti-neutrophil cytoplasmic antibodies) and anti-Saccharomyces cerevisiae antibodies. This review focuses on the value of these antibodies for diagnosing IBD, differentiating Crohn disease from ulcerative colitis, indeterminate colitis, monitoring disease, defining clinical phenotypes, predicting response to therapy, and as subclinical markers. Pancreatic antibodies and newly identified anti-microbial antibodies (anti-outer membrane porin C, anti-I2, and anti-flagellin) are also reviewed.

Therapeutic efficacy of infliximab on active Crohn's disease under nutritional therapy

OBJECTIVE

The aim of this investigation was to elucidate retrospectively the therapeutic effect of infliximab in patients with active Crohn's disease (CD) under nutritional therapy.

MATERIAL AND METHODS

Using a review of the clinical records in 24 nationwide institutions specializing in inflammatory bowel disease, the short-term effect of infliximab in 97 patients with active CD was retrospectively investigated. The Crohn's disease activity index (CDAI) at baseline and after 2 weeks of a single infliximab administration (5 mg/kg) was compared among patients under total parenteral nutrition (TPN group, n=36), those following an elemental or polymeric diet (EN group, n=49) and those without TPN and EN (NN group, n=12). A decrease in CDAI >or= 70 or a CDAI value <150 at 2 weeks was regarded as effective.

RESULTS

There was no difference in CDAI at baseline among the three groups. In each group, CDAI decreased significantly (from 250 (195-290) [median (interquartiles)] to 152 (123-233) in the TPN group, p<0.0001; from 259 (200-325) to 180 (130-238) in the EN group, p<0.0001; from 278 (222-291) to 164 (132-196) in the NN group, p=0.003). Infliximab was effective in 63.9% of patients in the TPN group, in 55.1% of those in the EN group and in 75% of the NN group. There was no statistical difference in efficacy among the three groups (p=0.4). Multivariate logistic regression analysis revealed younger age to be a significant factor related to the efficacy of infliximab.

CONCLUSIONS

Infliximab is effective in patients with CD under TPN or EN. Age at infliximab administration may be predictive of response to infliximab.

Antibodies to CBir1 flagellin define a unique response that is associated independently with complicated Crohn's disease

BACKGROUND & AIMS

Antibody responses to certain microbial antigens define heterogeneous groups of Crohn's patients; multiple and high-level responses to these antigens are associated with aggressive clinical phenotypes. The flagellin, CBir1, identified by investigations in the C3H/HeJBir mouse model, has been identified as a dominant antigen capable of inducing colitis in mice and eliciting antibody responses in a subpopulation of patients with Crohn's disease (CD). The aim of this study was to evaluate serum response to CBir1 flagellin in CD patients and to compare this response to responses defined previously to oligomannan (anti-Saccharomyces cerevisiae antibody), I2, OmpC, and neutrophil nuclear autoantigens (pANCA), and to determine anti-CBir1-associated phenotypes.

METHODS

A total of 484 sera from the Cedars Sinai Medical Center repository, previously typed for anti-Saccharomyces cerevisiae antibody, anti-I2, anti-OmpC, and pANCA were tested for anti-CBir1 by enzyme-linked immunosorbent assay, and results were assessed for clinical phenotype associations.

RESULTS

The presence and level of immunoglobulin G anti-CBir1 were associated with CD independently. Anti-CBir1 was present in all antibody subgroups and expression increased in parallel with increases in the number of antibody responses. pANCA+ CD patients were more reactive to CBir1 than were pANCA+ ulcerative colitis patients. Anti-CBir1 expression is associated independently with small-bowel, internal-penetrating, and fibrostenosing disease features.

CONCLUSIONS

Serum responses to CBir1 independently identify a unique subset of patients with complicated CD. This bacterial antigen was identified in a murine model and has a similar pattern of aberrant reactivity in a subset of CD patients.

Can we alter the natural history of Crohn disease in children?

The natural history of Crohn disease is characterized by recurrent bouts of active disease, the consequences of which can severely impair sufferers' physical and social functioning. Not only does the illness cause day-to-day morbidity for children but the consequence of the chronic inflammatory process also commonly results in the need for major intestinal surgery. The present challenge facing physicians treating children with Crohn disease is to alleviate symptoms and prolong periods of remission via the use of specifically targeted therapies while minimizing toxicity and promoting normal growth and development. Although systemic corticosteroids are effective in inducing clinical remission, they are of little or no benefit in maintaining remission and can contribute to linear growth retardation. Immunomodulating drugs such as azathioprine, 6-mercaptopurine and methotrexate have proved effective for inducing and maintaining remission of active Crohn disease. These agents are now commonly prescribed in children at diagnosis, after a severe attack or after surgery or in those who become corticosteroid-dependent or corticosteroid-resistant. Their use is not without potential adverse effects and not all patients respond well to these agents. With the introduction of biologic agents, notably the tumor necrosis factor-alpha monoclonal antibody infliximab, progress has been made in targeting specific pathogenetic mechanisms of Crohn disease and potentially altering the underlying disease process. Published experience in children is currently limited, but infliximab has been shown to improve symptoms and achieve corticosteroid independence in this age group. Unresolved issues with infliximab and other emerging biologic agents, including long-term safety, necessitate a degree of caution in selecting appropriate patients for treatment and with careful monitoring of their effects. The collection of contemporary natural history data is crucial to facilitate the better integration of current and emerging therapies in an attempt to alter the natural history of Crohn disease in children.

Are there predictors of Remicade treatment success or failure?

Infliximab (Remicade) is an antitumor necrosis factor (TNF) therapy effective in both induction and maintenance of remission in Crohn's disease. Identifying predictors of response or relapse to infliximab is important given the potential toxicities and cost of this therapy. Currently available data suggest that concurrent immunosuppressant therapy, certain clinical characteristics, biological and immunological markers, and gene polymorphism may correlate with response to infliximab. However, no single variable has been consistently shown or definitely proven in studies to be a predictor of response to infliximab to be of practical value in current clinical practice. Data from the literature in these areas are reviewed in this article, pointing to the need for additional research in this topic.

Biologic Therapy for Inflammatory Bowel Disease

Despite all of the advances in our understanding of the pathophysiology of inflammatory bowel disease (IBD), we still do not know its cause. Some of the most recently available data are discussed in this review; however, this field is changing rapidly and it is increasingly becoming accepted that immunogenetics play an important role in the predisposition, modulation and perpetuation of IBD. The role of intestinal milieu, and enteric flora in particular, appears to be of greater significance than previously thought. This complex interplay of genetic, microbial and environmental factors culminates in a sustained activation of the mucosal immune and non-immune response, probably facilitated by defects in the intestinal epithelial barrier and mucosal immune system, resulting in active inflammation and tissue destruction. Under normal situations, the intestinal mucosa is in a state of 'controlled' inflammation regulated by a delicate balance of proinflammatory (tumour necrosis factor [TNF]-alpha, interferon [IFN]-gamma, interleukin [IL]-1, IL-6, IL-12) and anti-inflammatory cytokines (IL-4, IL-10, IL-11). The mucosal immune system is the central effector of intestinal inflammation and injury, with cytokines playing a central role in modulating inflammation. Cytokines may, therefore, be a logical target for IBD therapy using specific cytokine inhibitors. Biotechnology agents targeted against TNF, leukocyte adhesion, T-helper cell (T(h))-1 polarisation, T-cell activation or nuclear factor (NF)-kappaB, and other miscellaneous therapies are being evaluated as potential therapies for IBD. In this context, infliximab is currently the only biologic agent approved for the treatment of inflammatory and fistulising Crohn's disease. Other anti-TNF biologic agents have emerged, including CDP 571, certolizumab pegol (CDP 870), etanercept, onercept and adalimumab. However, ongoing research continues to generate new biologic agents targeted at specific pathogenic mechanisms involved in the inflammatory process. Lymphocyte-endothelial interactions mediated by adhesion molecules are important in leukocyte migration and recruitment to sites of inflammation, and selective blockade of these adhesion molecules is a novel and promising strategy to treat Crohn's disease. Therapeutic agents that inhibit leukocyte trafficking include natalizumab, MLN-02 and alicaforsen (ISIS 2302). Other agents being investigated for the treatment of Crohn's disease include inhibitors of T-cell activation, peroxisome proliferator-activated receptors, proinflammatory cytokine receptors and T(h)1 polarisation, and growth hormone and growth factors. Agents being investigated for treatment of ulcerative colitis include many of those mentioned for Crohn's disease. More controlled clinical trials are currently being conducted, exploring the safety and efficacy of old and new biologic agents, and the search certainly will open new and exciting perspectives on the development of therapies for IBD.

Relevance of serologic studies in inflammatory bowel disease

The serologic panel for inflammatory bowel disease (IBD) is rapidly expanding. Antineutrophil cytoplasmic antibodies (ANCA) and anti-Saccharomyces cerevisiae mannan antibodies (ASCA) have remained the most widely studied markers, but immune reactivity against a new group of bacterial antigens such as I2, OmpC (outer membrane porin C), and flagellin, has been described in Crohn's disease. Several clinical avenues have been explored, such as the usefulness of serologic markers as screening tools for IBD and in accelerating a diagnosis in patients with indeterminate colitis. Another area of interest is disease stratification. Emerging data suggest there is a diversity of qualitative and quantitative responses to environmental antigens that differs among groups of IBD patients and may be associated with different clinical behaviors. As a result, it may be possible to tailor therapy on the basis of serologic responses. Prospective studies are needed before translating this concept into clinical practice. Clustering of IBD patients into more homogeneous subgroups based on antibody responses may help to unravel the pathophysiology of subsets of IBD.

Serologic testing with ANCA, ASCA, and anti-OmpC in children and young adults with Crohn's disease and ulcerative colitis: diagnostic value and correlation with disease phenotype

OBJECTIVES

Serologic testing is increasingly being utilized to evaluate children with suspected inflammatory bowel disease (IBD). The aim of this paper was to evaluate the sensitivity and specificity of a currently available panel involving four antibodies: deoxyribonuclease (DNase)-sensitive perinuclear antineutrophil cytoplasmic antibody (DNase-sensitive pANCA), IgA and IgG antibodies to Saccharomyces cerevisiae (IgA and IgG ASCA), and antibody to Escherichia coli outer membrane porin (anti-OmpC). We also wished to determine whether antibody levels correlated with disease activity, and whether a specific antibody pattern correlated with location and outcome of disease in children.

METHODS

We studied sera from 81 children with Crohn's disease (CD), 54 with ulcerative colitis (UC), and 63 controls. Clinical data, disease activity, and disease diagnosis were gathered at the time of serum sampling, and charts were re-reviewed at time of the study to determine long-term outcome. Enzyme-linked immunosorbent assay was utilized to determine titers of antibodies to ASCA, DNase-sensitive pANCA, and anti-OmpC; the presence of perinuclear staining for ANCA was confirmed by immunofluorescence.

RESULTS

We identified ASCA antibodies in 44% of CD patients, 0% of UC patients, and 1 control patient. DNase-sensitive pANCA antibodies were found in 70% of patients with UC, 18% of CD patients (predominantly Crohn's colitis), and 3% of controls. Anti-OmpC as an isolated assay had low sensitivity for both CD (24%) and UC (11%), and displayed a 5% false-positive rate. However, anti-OmpC did identify a small number of IBD patients not detected by the other assays. If any one or more of the four antibodies was positive, the overall sensitivity of the four antibody panel was 65% for CD and 76% for UC, with a specificity of 94%. Patients who were ASCA-positive were more likely to have disease of the ileum or ileum and right colon than patients who were ASCA-negative (58%vs 18%, p < 0.001). Patients with ASCA-positive were also more likely to require ileocecal resection (36%vs 13%, p < 0.05).

CONCLUSIONS

A currently available commercial antibody panel has good sensitivity and excellent specificity for CD and UC. The ASCA antibodies, while highly specific for CD, identify predominantly the subset of children with disease of the ileum and ascending colon who may be at increased risk of surgery.

Decrease of anti-cyclic citrullinated peptide antibodies and rheumatoid factor following anti-TNFalpha therapy (infliximab) in rheumatoid arthritis is associated with clinical improvement

OBJECTIVE

To investigate the effect of infliximab treatment on anti-cyclic citrullinated peptide antibodies (anti-CCP) and rheumatoid factor (RF) in patients with rheumatoid arthritis.

METHODS

43 patients with rheumatoid arthritis not responding to disease modifying anti-rheumatic drugs (DMARD) received intravenous infliximab at a dose of 3 mg/kg at baseline and after two and six weeks, and subsequently bimonthly, in combination with methotrexate. Serum samples were collected at baseline and at week 24. A commercial enzyme linked immunosorbent assay was used to test for anti-CCP antibodies; RF were detected using a quantitative nephelometric assay.

RESULTS

At baseline, 38 of the 43 patients (88%) were positive for anti-CCP antibodies, and 41 (95%) were positive for RF. The serum titre of anti-CCP and RF decreased significantly after six months of treatment (p = 0.0001 and p<0.0001, respectively). When the patients were grouped on the basis of their clinical response to infliximab, a significant decrease in serum anti-CCP antibodies and RF was observed only in patients who had clinical improvement (ACR 20 and ACR 50).

CONCLUSIONS

Anti-TNFalpha treatment in rheumatoid arthritis results in a decrease in the serum titres of RF and anti-CCP antibodies in patients showing clinical improvement, suggesting that these measurements may be a useful adjunct in assessing treatment efficacy.

Perianal Crohn's disease and infliximab therapy

INTRODUCTION

Perianal manifestations occur in almost half of patients with Crohn's disease and often respond poorly to conventional therapies. The introduction of anti-tumour necrosis factor alpha agents (e.g. infliximab) has altered the management of patients who fail first and second line medical and surgical therapies.

METHODS

We performed a literature search of the PubMed database using the Medical Search Headings infliximab, perianal Crohn's disease, fistulae, cost and safety. We also performed a manual search using references from these articles, review articles and proceedings from major gastroenterology meetings.

RESULTS

Use of infliximab, at a dose of 5mg/kg at intervals of 0, 2 and 6 weeks, results in significant improvement in disease in approximately 70% of patients with fistulae. Prior examination under anaesthesia with placement of non-cutting seton sutures in fistula tracks is a useful adjunct in many patients. Preliminary results show a benefit from maintenance infliximab therapy and from concomitant use of immunosuppressants such as azathioprine. No clinical or biochemical markers have been identified which predict non-response to infliximab, although its use is contraindicated in patients with strictures. Acute infusion reactions are the most common side-effect of infliximab therapy and they are usually mild. Despite initial fears, the incidence of opportunistic infection is low. There is inadequate information, at present, regarding a possible increase in incidence of lymphoma with infliximab therapy. Infliximab is expensive compared with established therapies and its use will increase the lifetime cost of treating Crohn's disease.

CONCLUSION

While infliximab is a useful adjunct in selected patients, the cornerstones of management of perianal Crohn's are essentially unchanged.

Biomarkers in inflammatory bowel disease

PURPOSE OF REVIEW

Inflammatory bowel disease is characterized by chronic intestinal inflammation in the absence of a recognized pathogen. In its classic description, there are two principal forms of inflammatory bowel disease: Crohn disease and ulcerative colitis. The clinical heterogeneity of these disorders alludes to the possibility of diverse pathogenetic mechanisms underlying inflammatory bowel diseases. The purpose of this review is to summarize the latest information on biomarkers of Crohn disease and ulcerative colitis.

RECENT FINDINGS

The authors have focused on serologic markers for which emerging data support their use as predictors of disease evolution. Serologic markers such as perinuclear antineutrophil cytoplasmic antibody, anti-Saccharomyces cerevisiae antibody, anti-OmpC, and anti-I2 may be useful in distinguishing inflammatory bowel diseases from functional disorders and ulcerative colitis from Crohn disease and predicting complications of disease. Genetic markers such as CARD15/NOD2 may be useful in the future when combined with other markers to predict disease course. Biochemical markers of inflammation such as C-reactive protein are useful to stratify patients likely to respond to biologic therapies and to follow response to treatment. In the future, functional genomics and proteomics will be used to rapidly screen patients for subclinical characteristics that can predict disease course and response to therapy.

SUMMARY

A variety of biomarkers can be used to stratify patients with inflammatory bowel disease into more homogeneous subgroups with respect to response to therapy and disease progression.

Smoking and immunomodulators do not influence the response or duration of response to infliximab in Crohn's disease

OBJECTIVE

Clinical predictors for infliximab response are still unknown. Identifying predictors of response to infliximab in Crohn's disease may improve our selection of patients.

METHODS

Two hundred patients with luminal (61%) or fistulous (39%) Crohn's disease and at least 6 months of follow-up following a total of 416 infliximab infusions were evaluated. Clinical response and duration of response were the primary endpoints.

RESULTS

Patients with fistulous disease had a higher response rate (83% versus 70%, P = 0.044) and a significantly longer duration of response compared with patients with luminal disease (17.4 versus 10.1 wks, P = 0.017). For luminal disease, nonsmokers and smokers had similar response rates (74% versus 64%, P = 0.5) and similar durations of response (9.4 wks versus 8.4 wks P = 0.6) while patients taking concurrent immunomodulators had similar response rates compared with those not taking immunomodulators (74% versus 71%, P = 0.9) and similar durations of response (10.4 wks versus 10.6 wks, P = 0.9). For fistulous disease, response rates (89% versus 83% P = 0.9) and duration of response (16.9 wks versus 10.1 wks, P = 0.10) were similar between nonsmokers and smokers and concurrent immunomodulators had no effect on response (89% versus 86%, P = 0.9) or duration of response (19.8 wks versus 15.4 wks, P = 0.46). Multivariable analysis confirmed that neither smoking, corticosteroids, immunomodulator therapy, gender, age, age of disease onset, disease duration, nor luminal disease location significantly influenced response or duration of response.

CONCLUSIONS

Patients with fistulous disease had a higher response rate and a significantly longer duration of response compared with patients with luminal disease. However, among patients with luminal or fistulous disease, neither smoking nor immunomodulators had any effect on response or duration of response.

Choosing Therapy on the Basis of Disease Classifications in Inflammatory Bowel Disease

Crohn's disease and ulcerative colitis (UC) are heterogeneous disorders, and as such, the response to therapy is likewise heterogeneous. Therefore, stratification of patients into distinct phenotypes and potentially genotypes will lead to more definitive answers with respect to evaluation of novel and established therapies.

Pharmacogenetics of inflammatory bowel disease

The therapeutic efficacy and toxicity of many commonly employed drugs show interindividual variations that relate to several factors, including genetic variability in drug-metabolizing enzymes, transporters or targets. The study of the genetic determinants influencing interindividual variations in drug response is known as pharmacogenetics. The ability to identify, through preliminary genetic screening, the patients most likely to respond positively to a medication should facilitate the best choice of treatment for each patient; drugs likely to exhibit low efficacy or to give negative side-effects can be avoided. Among the medications used for inflammatory bowel disease, the best studied pharmacogenetically is azathioprine. The hematopoietic toxicity of azathioprine is due to single nucleotide polymorphisms in the thiopurine S-methyltransferase enzyme. Additionally, likely gene targets have been investigated to predict the response to glucocorticoids and infliximab, a monoclonal antibody against tumour necrosis factor that induces remission in approximately 30-40% of patients. However, no genetic predictor of response has been identified in either case.

Optimizing anti-TNF treatment in inflammatory bowel disease

Infliximab, the chimeric monoclonal immunoglobulin (Ig)G1 antibody to tumor necrosis factor (TNF) has changed our therapy of Crohn's disease. Infliximab is indicated in refractory luminal and fistulizing Crohn's disease. In patients with luminal disease, a single intravenous (i.v.) dose of 5 mg/kg is efficacious; in fistulizing disease, an i.v. loading therapy of 5 mg/kg at weeks 0, 2, and 6 is advocated. Because the majority of patients will relapse if not re-treated, a long-term strategy is necessary. The optimal long-term approach is systematic re-treatment with 5 mg/kg every 8 weeks. Episodic therapy on relapse also is possible but is less efficacious and frequently is associated with problems resulting from the formation of antibodies to infliximab (ATI). If treatment is episodic, maintenance therapy with immunosuppression (azathioprine [AZA]/6-mercaptopurine [6-MP] or methotrexate) is mandatory. Trial data suggest that systematic maintenance with 8 weekly doses of infliximab decreases the rate of complications, hospitalizations, and surgeries. These effects probably are achieved thanks to thorough healing of the bowel. Infliximab also is indicated in treating corticosteroid-dependent Crohn's disease and extraintestinal manifestations of Crohn's disease. There are no data yet that support its use as first-line therapy. The data in ulcerative colitis (UC) are conflicting and we should await the results of 2 large controlled trials (ACT1 and ACT2) to position infliximab in the treatment of UC. Other anti-TNF strategies have been less effective than infliximab in the treatment of IBD until now. The results with thalidomide are promising but much more research into small molecules inhibiting TNF and other proinflammatory cytokines is necessary. Safety problems with antibody treatment mainly concern immunogenicity leading to infusion reactions, loss of response, and serum sickness-like delayed infusion reactions. The rate of opportunistic infections is increased mainly in patients treated concomitantly with immunosuppression. Other adverse events associated with anti-TNF strategies are demyelinating disease and worsening of congestive heart failure. Malignancy rates in patients treated with anti-TNF strategies do not seem to be increased.

Infliximab in pediatric ulcerative colitis: two-year follow-up

OBJECTIVES

The role of infliximab in treating pediatric ulcerative colitis (UC) is not defined. The authors previously have described their experience with the open label use of infliximab in nine children with moderate to severe UC. The aim of this study was to describe the outcome of these patients after a minimum 2-year follow-up and to describe the responses of eight additional patients to this medication.

METHODS

The authors reviewed all pediatric patients with UC who received infliximab at The Children's Hospital of Philadelphia from its first use until February 2003. Tolerance of the infusions and adverse events were recorded.

RESULTS

Follow-up information for a minimum of 2 years was reviewed for the nine initial patients. A total of 73 infliximab infusions were administered to these patients. Seven of nine (78%) patients were considered to be responders to the initial dose of infliximab. Two of these patients became nonresponders within 9 months of the first dose of infliximab and underwent colectomy. Of the remaining five (56%) patients with sustained response, two continue to receive infliximab infusions and three are doing well without infliximab. One patient experienced an infusion reaction, and one experienced herpes zoster infection. We have treated eight additional UC patients with infliximab. Seven (88%) patients were considered responders. One responder experienced relapse within 2 months. Overall, a short-term improvement was seen in 14 of 17 (82%) patients, and sustained improvement in 10 of 16 (63%) patients followed up for more than 9 months. All five patients with severe or fulminant UC, unresponsive to 2 weeks of intravenous corticosteroid therapy, experienced improvement with infliximab. Infliximab was well tolerated.

CONCLUSION

Infliximab is associated with short- and long-term clinical improvement in children and adolescents with moderate to severe UC.

The biology of TNF blockade

Rheumatoid arthritis and Crohn's disease are costly diseases that result in significant long-term patient disability. They are chronic inflammatory diseases that are associated with increased production of Tumor Necrosis Factor (TNF). Blockage of this cytokine with bio-engineered compounds has significantly changed therapy of these diseases and has ushered in the era of biological therapy. The pro-inflammatory role of TNF is mediated by its essential respiratory burst function that is effectively inhibited by anti-TNF therapy. Anti-TNF therapy is effective in approximately two-thirds of patients to whom it is administered, but the effect is temporary. Lack of response to anti-TNF therapy stems from interplay of host-factors including: host cytokine response, disease phenotype, and antibody response to the anti-TNF agents. NOD 2, a defect present in approximately 50% of Crohn's disease patients, bears no relationship to non-response. Additionally, TNF promoter gene polymorphisms and TNF receptor gene heterogeneity play a significant role in non-response and disease course/severity. Adverse effects of anti-TNF therapy include early and delayed hypersensitivity reactions, cell-mediated infections, lupus-like syndrome, demyelinating diseases, and exacerbation of CHF.

Evaluation of new therapies for inflammatory bowel disease

The pathophysiology of inflammatory bowel disease (IBD) is gradually being unravelled and new therapies are being developed to target the disturbed biological processes. This article outlines the clinical features of IBD, its current therapy and pathogenesis. The difficulties for clinical pharmacologists and gastroenterologists associated with designing, executing and interpreting clinical trials in IBD are then discussed. The final section reviews methods that can used to demonstrate the pharmacological actions of new treatments in patients with IBD. It is emphasized that proof of the therapeutic efficacy of a novel agent with a specific mechanism of action yields not only clinical benefit to patients with IBD, but also indicates the importance of the targeted biochemical pathway in the pathogenesis of the disease.

Anti-Saccharomyces cerevisiae antibodies: a stable marker for Crohn's disease during steroid and 5-aminosalicylic acid treatment

OBJECTIVES

An increased prevalence of elevated serum anti-Saccharomyces cerevisiae antibody (ASCA) levels in patients with Crohn's disease (CD) has been described. The aim of the present work was to investigate serum ASCA levels during the courses of prednisolone and mesalamine therapy in CD patients.

METHODS

Serum samples of 25 patients with active CD were studied for ASCA levels before as well as 2 and 9 wk after initiation of a prednisolone tapering regimen. The influence of mesalamine (4 g o.d.) on serum ASCA levels compared to that of placebo was tested over 1 yr in 38 patients (20 mesalamine and 18 placebo) participating in a postoperative prophylaxis study. Serum IgG and IgA ASCA levels were measured by ELISA. Sera of 91 CD and 40 ulcerative colitis (UC) patients as well as 334 healthy donors were tested for ASCA to recalculate new cut-off values.

RESULTS

For IgG ASCA cut-off values were determined to be 17.0 U and 25.0 U, and for IgA ASCA 9.3 U and 14.0 U. At baseline visit, 73.0% (46/63) of patients displayed serum ASCA positivity. During prednisolone therapy, a decrease in serum IgG and IgA ASCA levels from baseline to wk 2 (p < 0.0001 and p < 0.001, respectively) as well as to wk 9 (p < 0.001 and p = 0.01, respectively) was observed. A trend toward an association of ASCA positivity and steroid responsiveness was calculated (p = 0.07). During mesalamine treatment, no differences in changes of ASCA levels were observed compared to placebo at any time point.

CONCLUSIONS

ASCA are stable markers during steroid and mesalamine treatment, highlighting their reliability for use in diagnosis of CD.

An analysis of factors influencing short-term and sustained response to infliximab treatment for Crohn's disease

BACKGROUND

59-81% of patients given infliximab for Crohn's disease will respond. Although now in widespread use, little consensus exists regarding the optimal place in patient care. Recently developed guidelines have identified need for markers that predict response.

AIMS

We aimed to identify markers of response to infliximab given for Crohn's disease.

METHODS

Markers of response (defined at 4 weeks) were prospectively assessed in 74 infliximab-treated patients with Crohn's disease. Patients were followed-up to 1 year.

RESULTS

Fifty-four of 74 (73%) patients responded. Univariate analysis identified that smokers were less likely to respond than non-smokers [P = 0.005, odds ratio (OR) 0.22]. Patients established on immunosuppression (P = 0.034, OR 7.31) and with isolated colonic disease (P = 0.042, OR 3.83) were more likely to respond. Multiple logistic regression confirmed smoking (P = 0.035, OR 0.24) and colonic disease (P = 0.035, OR 4.87) as independent markers of response. One-year relapse rates differed significantly between smokers and non-smokers (100% vs. 39.6%, P = 0.0026, relative risk 3.2) and between patients established on immunomodulators or not (58.0% vs. 92.8%, P = 0.0054, relative risk 2.6).

CONCLUSIONS

Smoking has a strong adverse effect on the response rates and maintenance of response to infliximab. Patients on immunomodulators have a more favourable short- and long-term response. These results have important implications for clinical practice.

Overview of the use of the anti-TNF agent infliximab in chronic inflammatory diseases

Anti-inflammatory therapy with monoclonal antibodies (mAbs) directed against tumour necrosis factor (TNF)-alpha has emerged as a major advancement in the treatment of various immune mediated diseases such as rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis and Crohn's disease. TNF-alpha seems to play a major pathogenic role in these chronic immune-mediated inflammatory diseases. Infliximab (Remicade), Centocor, Inc., Malvern, PA, USA), a chimaeric mAb, binds to soluble and membrane bound TNF-alpha, but not to TNF-beta. Infliximab is able to effectively regulate and mediate inflammatory processes involved in a number of different disease states. Many clinical trials in these diseases have demonstrated that biological therapy with mAbs directed against TNF-alpha is effective and relatively safe.

Azathioprine and anti-TNF alpha therapies in Crohn's disease: a review of pharmacology, clinical efficacy and safety

Crohn's disease (CD), a chronic relapsing inflammatory condition of the intestines, is a common cause of gastrointestinal morbidity in young people. Although the aetiology of CD is unknown, host, genetic and environmental influences are clearly important. Glucocorticoids remain the mainstay of treatment for active CD, however only two-third of patients will respond and side effects are considerable. Surgery is often undesirable or impracticable and therefore alternative medical strategies have been sought. In recent years, there has been much interest in two areas of IBD therapy-the use of established immunomodulators, and the development of novel biological therapies. In this review, we have selected two areas of particular controversy-the use of purine analogues (azathioprine (AZA) and 6-mercaptopurine (6-MP)) and the introduction of anti-tumour necrosis factor alpha (TNFalpha) therapy and have examined the data for efficacy, safety and tolerability of these medications.