Assessing response and loss of response to biological therapies in IBD

Infliximab therapy in pediatric patients 7 years of age and younger

BACKGROUND

Infliximab (IFX) is efficacious for induction and maintenance of remission in pediatric patients with moderate-to-severe inflammatory bowel disease (IBD). It has, however, not been studied in patients 7 years old and younger. Our aim was to characterize efficacy and safety of IFX therapy in this cohort.

METHODS

This was a retrospective study of patients with IBD ages 7 years and younger, treated with IFX between 1999 and 2011. Medical records were reviewed for age of diagnosis, disease phenotype, therapy, surgery, IFX infusion dates, dose, and intervals. Outcome measures included physician global assessment, corticosteroid requirement, and adverse events.

RESULTS

Thirty-three children (ages 2.4-7 years) were included. Twenty patients had Crohn disease, 4 had ulcerative colitis, and 9 had indeterminate colitis. Maintenance of IFX therapy at 1, 2, and 3 years was 36%, 18%, and 12%, respectively. Patients of age 5 years and younger had the lowest rates of maintenance of therapy at 25% at year 1, and 10% at years 2 and 3 combined. Nine percent of all of the patients demonstrated response measured by the physician global assessment and were steroid free at 1 year. There were 8 infusion reactions. There were no malignancies, serious infections, or deaths.

CONCLUSIONS

IFX demonstrated a modest response rate and a low steroid-sparing effect in patients with IBD 7 years old and younger. Although this is a limited study, there appears to be a trend for decreased sustained efficacy with IFX in this age group, particularly in children 5 years old and younger, when compared with the previously published literature in older children.

Patient factors that increase infliximab clearance and shorten half-life in inflammatory bowel disease: a population pharmacokinetic study

BACKGROUND

Infliximab (IFX) is effective therapy for ulcerative colitis and Crohn's disease, but it may be associated with side effects and loss of response. One loss of response mechanism is increased IFX clearance (IFX-CL), resulting in short half-life and decreased troughs.

METHODS

Patients were recruited, and relevant demographic, clinical, and laboratory data were recorded. IFX serum concentrations and antibodies against IFX (ATI) were measured for therapeutic drug monitoring and modeled using NONMEM.

RESULTS

There were 169 IFX concentrations (Crohn's disease = 73, ulcerative colitis = 92, and diagnosis undetermined = 4). Patient factors significantly associated with high IFX-CL were low albumin, high body weight, and the presence of ATI (P ≤ 0.001). Disease type did not affect IFX-CL. The typical IFX-CL was 0.381 L/d. ATI formation was associated with a 259% increase in IFX-CL. The estimated median IFX effective half-life was 5.6 ± 2.4 days. Patients with low weight are more likely to have low troughs because IFX CL is not linearly related to weight, but IFX dosing is weight-based (in mg/kg). Simulations investigating alternative dose strategies suggested that more reliably measurable concentrations over the dose interval were achieved when the dose interval was shortened than by increasing administered dose.

CONCLUSIONS

IFX-CL is significantly influenced by patient factors, specifically, albumin, body weight, and ATI. There should be a decreasing IFX dose interval strategy, particularly for low albumin patients. Higher starting doses may benefit low body weight patients. Pharmacokinetic models and therapeutic drug monitoring may ensure that patients maintain measurable concentrations throughout dose intervals. Individualized dosing may improve outcomes for IFX-treated patients with Crohn's disease and ulcerative colitis.

Subcutaneous ustekinumab for the treatment of anti-TNF resistant Crohn's disease--the McGill experience

BACKGROUND

Ustekinumab is a fully human IgG1κ monoclonal antibody that blocks the biologic activity of interleukin-12/23. Ustekinumab is approved for treatment of plaque psoriasis and has been shown to be effective for induction and maintenance of clinical response in anti-TNF resistant Crohn's disease (CD). The aim of the study was to describe the real-life experience with open-label use of ustekinumab in anti-TNF resistant CD patients.

METHODS

A retrospective observational open-label study. Clinical response was defined by physician's global assessment combined with decision to continue therapy. The clinical response was evaluated at 3, 6, 12months and last follow-up.

RESULTS

Thirty-eight patients were included in the study. Initial clinical response was achieved in 28/38 (73.7%) of the patients. Among the initial responders, 80% with follow-up data maintained their response for 6months. At 12months of follow-up, 88.9% of patients responding at 6months maintained their response. At the last follow-up (7.9±5.2 mo) 27/38 (71%) of the patients were responding, and 73.3% were able to discontinue corticosteroids. Dose escalation was required in 47.7% of the patients and was successful in 61.1% of them.

SUMMARY

In this real-life cohort of severe anti-TNF resistant CD, an initial clinical response to subcutaneous ustekinumab was observed in 73.7% of the patients. The initial response was successfully maintained in the majority of patients for up to 12months. Subcutaneous ustekinumab is an effective therapeutic option in this challenging patient cohort. The optimal dosing and injection schedule remain to be established in future studies.

Update on anti-tumor necrosis factor agents in Crohn disease

Anti-tumor necrosis factor-α (TNF) agents, including infliximab, adalimumab, and certolizumab pegol, are effective medications for the management of moderate to severe Crohn disease (CD). They are effective in inducing and maintaining clinical remission, inducing mucosal healing, improving quality of life, and reducing the risk of hospitalization and surgery in adult and pediatric patients with CD. Future research into comparative effectiveness of different agents, as well as better understanding of predictors of response, is warranted to allow optimization of therapeutic response.

Escalation to weekly dosing recaptures response in adalimumab-treated patients with moderately to severely active ulcerative colitis

BACKGROUND

Patients with moderately to severely active ulcerative colitis occasionally do not respond to or lose initial response to maintenance dosing of anti-TNF therapy.

AIM

To report the efficacy of escalation from every other week (EOW) to weekly adalimumab dosing in patients from the clinical trial ULTRA 2 (NCT00408629), by week 8 response (i.e. response after adalimumab induction therapy).

METHODS

Week 52 remission, response, and mucosal healing rates were assessed in ULTRA 2 adalimumab-randomised patients who escalated to weekly dosing. Patients were stratified by week 8 response per partial Mayo score. Kaplan-Meier and logistic regression analyses estimated time to weekly dosing and defined predictors of escalation to weekly dosing, respectively. Adverse events were reported for patients receiving open-label adalimumab.

RESULTS

The rate of escalation to weekly dosing was 16.3% (20/123) for week 8 responders and 38.4% (48/125) for week 8 nonresponders. Week 52 remission, response and mucosal healing rates with weekly dosing were 20%, 45%, and 45% for week 8 responders and 2.1%, 25% and 29.2% for nonresponders, respectively (NRI). The median time to weekly dosing was 288 days for week 8 nonresponders and not estimable for responders. Prior anti-TNF use was a significant predictor of escalation to weekly dosing. Treatment-emergent adverse event rates were similar for patients receiving open-label EOW or weekly adalimumab.

CONCLUSIONS

Escalation to weekly adalimumab dosing demonstrated clinical benefits for patients who lost response to therapy and may be beneficial for patients not initially responding to induction therapy. No new safety risks were identified with weekly dosing.

Investigation of the immunogenicity of different types of aggregates of a murine monoclonal antibody in mice

PURPOSE

The potential contribution of protein aggregates to the unwanted immunogenicity of protein pharmaceuticals is a major concern. In the present study a murine monoclonal antibody was utilized to study the immunogenicity of different types of aggregates in mice. Samples containing defined types of aggregates were prepared by processes such as stirring, agitation, exposure to ultraviolet (UV) light and exposure to elevated temperatures.

METHODS

Aggregates were analyzed by size-exclusion chromatography, light obscuration, turbidimetry, infrared (IR) spectroscopy and UV spectroscopy. Samples were separated into fractions based on aggregate size by asymmetrical flow field-flow fractionation or by centrifugation. Samples containing different types and sizes of aggregates were subsequently administered to C57BL/6 J and BALB/c mice, and serum was analyzed for the presence of anti-IgG1, anti-IgG2a, anti-IgG2b and anti-IgG3 antibodies. In addition, the pharmacokinetic profile of the murine antibody was investigated.

RESULTS

In this study, samples containing high numbers of different types of aggregates were administered in order to challenge the in vivo system. The magnitude of immune response depends on the nature of the aggregates. The most immunogenic aggregates were of relatively large and insoluble nature, with perturbed, non-native structures.

CONCLUSION

This study shows that not all protein drug aggregates are equally immunogenic.

Autoregressive cross-lagged models of IMPACT-III and Pediatric Crohn's Disease Activity Indexes during one year infliximab therapy in pediatric patients with Crohn's disease

BACKGROUND

Quality of life (QoL) is an important outcome measure in the evaluation of therapies for inflammatory bowel disease. The primary aim of this study was to determine the effect of one year infliximab treatment on QoL and clinical parameters in pediatric patients with Crohn's diseases (CD).

METHODS

Our prospective study involved 51 children with conventional therapy resistant, severe CD (mean age: 15.25years, range: 11-18years). Infliximab was given according to the protocol (5mg/kg, at weeks 0, 2, 6 and every 8weeks). During the infliximab courses QoL of patients was evaluated by IMPACT-III questionnaire at weeks 0, 6, 30 and 53. At the same time, the Pediatric Crohn's Disease Activity Index (PCDAI) score was calculated. Moreover, serum C-reactive protein (CRP), serum platelets and serum albumin were followed up. Auto-regressive, cross-lagged models were used to assess relation between QoL and the clinical parameters.

RESULTS

The initial IMPACT-III scores [median, percentile 25-75 (pc 25-75) at week 0: 115, 102.5-130.25] increased significantly (p<0.001) following infliximab therapy at week 54 (median: 141.5, 124.5-153.75). Clinical and laboratory parameters also improved significantly (p<0.001). Auto-regressive regression coefficients (β value) were significant between each variable over time. The strongest cross-lagged relations were observed between IMPACT-III and serum albumin, IMPACT-III and platelets. Reliability test of IMPACT-III revealed an excellent level of internal consistency (Cronbach's alpha=0.931).

CONCLUSION

Infliximab treatment has beneficial clinical effect which is confirmed by decrease of PCDAI and increase of IMPACT-III. Autoregressive regression analysis showed regression relation between IMPACT-III and PCDAI and laboratory parameters.

The temporal evolution of antidrug antibodies in patients with inflammatory bowel disease treated with infliximab

OBJECTIVE

To characterise the temporal evolution of antibodies to infliximab (ATI).

DESIGN

Prospective observational study of infliximab-treated patients with inflammatory bowel disease between 2009 and 2012.

INTERVENTIONS

Trough levels of infliximab and ATI were measured before each infusion by anti-λ ELISA. Patients were monitored for disease activity by clinical activity indexes and for dose-intensification or infliximab cessation. The occurrence of transient ATI disappearing spontaneously without intervention was recorded separately.

RESULTS

125 patients were included (98 Crohn's disease, 27 ulcerative colitis, median follow-up 11.5±22 months) and 1119 sera were analysed for infliximab and ATI levels. Kaplan-Meier analysis showed that 42% of patients remained ATI-free by 4 years of treatment. Most (90%) of the patients who developed ATI did so within the first 12 months of therapy, whereas transient ATI were detected throughout the duration of infliximab therapy (p<0.001). ATI incidence was similar between patients who received infliximab previously (episodic/interrupted therapy patients, n=14) and scheduled-therapy patients (n=111). In the scheduled group, combination immunomodulator+infliximab resulted in longer ATI-free survival compared with monotherapy (p=0.003, logrank test). Survival free of clinical loss of response was enjoyed by 51% of patients, and serial measurements showed that ATI development often preceded the onset of clinical flare.

CONCLUSIONS

When followed prospectively, most patients who develop ATI do so within the first 12 months of therapy. This incidence is reduced by concomitant immunomodulator even in scheduled-therapy patients. In contrast, transient ATI, which are of little clinical significance, can appear haphazardly at any time during treatment. The onset of clinical loss of response may lag behind the appearance of anti-infliximab antibodies.

Comparison of efficacy, pharmacokinetics, and immunogenicity between infliximab mono- versus combination therapy in ulcerative colitis

BACKGROUND

The association of concomitant immunosuppressant use with infliximab (IFX) and therapeutic outcomes in correlation with pharmacokinetic properties in ulcerative colitis (UC) remains unclear.

AIMS

To assess the effect of concomitant immunosuppressant use on the duration of IFX therapy, and the pharmacokinetic properties of IFX in patients with UC.

METHODS

A retrospective analysis of UC patients treated with IFX. Duration of efficacious IFX therapy, and serum IFX and antibody-to-IFX (ATI) levels were compared between those receiving IFX as monotherapy and in combination with an immunosuppressant.

RESULTS

Among the 85 UC patients who received IFX, 46 (54.1%) received concomitant immunosuppressants, and 38 (45.9%) received IFX monotherapy. Concomitant immunosuppressant use was associated with increased duration of IFX therapy as 90% of patients receiving immunosuppressants remained on therapy at 1 year versus 61% of patients on monotherapy (Log-rank, P = 0.016). Concomitant immunosuppressant use, as compared with monotherapy, was associated with greater IFX levels (20.4 mg/L vs 10.5 mg/L, P = 0.025) and less frequent ATI formation (4.5% vs 33.3%, P = 0.031). Patients receiving greater than 2.0 mg/kg of azathioprine had greater IFX lev l than those receiving less than 2.0 mg/kg (26.0 vs 10.6 mcg/mL, P = 0.03) and those receiving IFX monotherapy (26.0 vs 11.2 mcg/mL, P = 0.03). The duration of IFX therapy among patients receiving less than 2.0 mg/kg azathioprine was indistinguishable from patients on IFX monotherapy (Log-rank, P = 0.95).

CONCLUSION

Concomitant immunosuppressant therapy with IFX improves outcomes in UC as shown by increased duration of therapy, decreased immunogenicity against IFX, and increased blood levels of IFX. Our data suggest that this benefit may be dependent on the dose of concomitant immunosuppression.

Individualised therapy is more cost-effective than dose intensification in patients with Crohn's disease who lose response to anti-TNF treatment: a randomised, controlled trial

OBJECTIVE

Although the reasons for secondary loss of response to infliximab (IFX) maintenance therapy in Crohn's disease vary, dose intensification is usually recommended. This study investigated the cost-effectiveness of interventions defined by an algorithm designed to identify specific reasons for therapeutic failure.

DESIGN

Randomised, controlled, single-blind, multicentre study. 69 patients with secondary IFX failure were randomised to IFX dose intensification (5 mg/kg every 4 weeks) (n=36) or interventions based on serum IFX and IFX antibody levels using the proposed algorithm (n=33). Predefined co-primary end points at week 12 were proportion of patients responding (Crohn's Disease Activity Index (CDAI) decrease ≥ 70, or ≥ 50% reduction in active fistulas) and accumulated costs related to treatment of Crohn's disease, expressed as mean cost per patient, based on the Danish National Patient Registry for all hospitalisation and outpatient costs in the Danish healthcare sector.

RESULTS

Costs for intention-to-treat patients were substantially lower (34%) for those treated in accordance with the algorithm than by IFX dose intensification: € 6038 vs € 9178, p<0.001. However, disease control, as judged by response rates, was similar: 58% and 53%, respectively, p=0.81; difference 5% (-19% to 28%). For per-protocol patients, treatment costs were even lower (56%) in the algorithm-treated group (€ 4062 vs € 9178, p<0.001) and with similar response rates (47% vs 53%, p=0.78; difference -5% (-33% to 22%)).

CONCLUSIONS

Treatment of secondary IFX failure using an algorithm based on combined IFX and IFX antibody measurements significantly reduces average treatment costs per patient compared with routine IFX dose escalation and without any apparent negative effect on clinical efficacy.

TRIAL REGISTRATION NO

NCT00851565.

Biological therapy in a pediatric Crohn disease population at a referral center

OBJECTIVE

The antitumor necrosis factor α (TNFα) antibodies infliximab and adalimumab are effective in inducing and maintaining remission in pediatric patients with Crohn disease (CD). The aim of the study was to evaluate the long-term efficacy and safety of biological therapy in pediatric patients with CD followed at a referral center.

METHODS

This work is a retrospective observational study enrolling patients with CD treated with infliximab or adalimumab beyond the induction protocol. The patients' data were collected from the unit's IBD database (maximum follow-up evaluation after 36 months of treatment). The efficacy was evaluated by the Pediatric Crohn Disease Activity Index score and by analysis of the cumulative probability of continuing therapy; the safety was assessed in terms of adverse events.

RESULTS

We enrolled 78 patients; the mean therapy duration was 27.2 ± 16.7 months, and the mean age at enrollment was 15 ± 3.1 years. The Kaplan-Meier analysis showed a cumulative probability of continuing therapy of 81%, 54%, and 33% at 1, 2, and 3 years, respectively, from the introduction of therapy. No association between the patients' baseline characteristics and the long-term outcome was found. The evaluation of the concomitant therapy with immunomodulators and anti-TNFα therapy versus anti-TNFα alone did not show a different outcome. No serious adverse events were recorded.

CONCLUSIONS

The study indicates that biological therapy is effective and safe in pediatric patients with CD in a longer follow-up period. The response to treatment was not influenced by the patients' baseline characteristics or by the immunomodulator association.

Assessment and reporting of the clinical immunogenicity of therapeutic proteins and peptides-harmonized terminology and tactical recommendations

Immunogenicity is a significant concern for biologic drugs as it can affect both safety and efficacy. To date, the descriptions of product immunogenicity have varied not only due to different degrees of understanding of product immunogenicity at the time of licensing but also due to an evolving lexicon that has generated some confusion in the field. In recent years, there has been growing consensus regarding the data needed to assess product immunogenicity. Harmonization of the strategy for the elucidation of product immunogenicity by drug developers, as well as the use of defined common terminology, can benefit medical practitioners, health regulatory agencies, and ultimately the patients. Clearly, understanding the incidence, kinetics and magnitude of anti-drug antibody (ADA), its neutralizing ability, cross-reactivity with endogenous molecules or other marketed biologic drugs, and related clinical impact may enhance clinical management of patients treated with biologic drugs. To that end, the authors present terms and definitions for describing and analyzing clinical immunogenicity data and suggest approaches to data presentation, emphasizing associations of ADA development with pharmacokinetics, efficacy, and safety that are necessary to assess the clinical relevance of immunogenicity.

Management of Crohn's disease in poor responders to adalimumab

Anti-tumor necrosis factor therapy with adalimumab is an effective therapy for the induction and maintenance of remission in moderate to severe Crohn’s disease. Although a large proportion of patients show a favorable clinical response to adalimumab, therapy failure is common. In this review, we provide a practical overview of adalimumab therapy in patients with Crohn’s disease, with a specific focus on the clinical management of adalimumab failure. In the case of inadequate efficacy, a thorough assessment is required to confirm inflammatory disease activity and rule out noninflammatory causes. Evaluation may include biomarkers (fecal calprotectin and serum C-reactive protein), colonoscopy, and/or magnetic resonance enterography/enteroclysis. Furthermore, adalimumab trough levels and antibodies to adalimumab are informational after the confirmation of active inflammation. In the case of low or undetectable adalimumab trough levels, dose escalation to 40 mg weekly is recommended, whereas high antibody titers or adverse events frequently require switching to an alternative anti-TNF agent such as infliximab. Active inflammation despite therapeutic adalimumab trough levels requires alternative strategies such as switching to drugs with a different mode of action or surgical intervention.

Tailoring anti-TNF therapy in IBD: drug levels and disease activity

The treatment of IBD with anti-TNF agents has substantially evolved since their first introduction more than a decade ago. The robust efficacy witnessed in many patients has raised new questions pertaining to the observation of subgroups of patients who fail to respond or who lose response to these otherwise very effective drugs. Conversely, the exorbitant cost of biologic agents coupled with their efficacy in inducing lasting remission has introduced new concepts addressing the possibility of therapy cessation in some patients after deep remission has been achieved. Measuring drug and anti-drug antibody (ADA) levels which develop in some patients has emerged as a valuable tool in understanding the mechanisms responsible for some of these clinical scenarios. However, knowledge on how to use these measurements to guide clinical decisions in daily practice is still in its nascency and awaits prospective validation trials. Furthermore, as described in this Review, knowledgeable interpretation of drug and ADA test results mandates understanding the interplay between the technical profile of the assay used, the timing of the measurement in the drug cycle, assessment of disease activity, and the profoundly different pharmaco-clinical scenarios that can culminate in a similar test result.

The long-term outcome of anti-tumor necrosis factor-α therapy related to fecal calprotectin values during induction therapy in pediatric inflammatory bowel disease

OBJECTIVE

Monitoring fecal calprotectin (FC) could assist in the assessment of the therapeutic response of inflammatory bowel disease (IBD). There are few studies on long-term prognosis related to the FC value response to infliximab induction therapy, thus providing the aim of this study on pediatric patients.

METHODS

FC levels were measured during the induction and maintenance phase of infliximab therapy (5 mg/kg) in 76 pediatric IBD patients introduced to maintenance therapy. The long-term outcomes and clinical disease activity were retrospectively related to the FC response to induction.

RESULTS

The median pretreatment FC level of 817 μg/g stool (range <5-24,000) declined to 372 μg/g (range 5-2430) by week 6, with a low level (<100 μg/g) in 35% (pooled comparable data for ulcerative colitis and Crohn's). Clinical activity indices showed remission in 59% (pediatric Crohn's disease activity index: <10, n = 33; pediatric ulcerative colitis activity index: <10 n = 12). In 49 patients (64%), infliximab therapy was discontinued (inadequate effect/surgery = 27; remission/bridging to azathioprine = 12; adverse effect = 6; antibodies to infliximab n = 4) during the study period with a median follow up of 1.1 years (interquartile range [IQR]: 0.71-4.4). Those who discontinued the therapy within the first year due to an inadequate effect had higher median FC level during induction than the other patients (median 633 µg/g, IQR: 197-819 and median 219 µg/g, IQR: 71-508, respectively; p < 0.025) and were less frequently in clinical remission at week 6 (p < 0.01).

CONCLUSIONS

The long-term prognosis of infliximab therapy is related to the response to induction therapy in pediatric IBD and reflected in low FC values between weeks 2 and 6 and clinical remission.

Relationship between serum infliximab trough levels and endoscopic activities in patients with Crohn's disease under scheduled maintenance treatment

BACKGROUND AND AIMS

Few data are available to support the clinical relevance of infliximab (IFX) trough levels for prediction of endoscopic disease activity in Crohn's disease (CD). This study evaluated the endoscopic disease activities in relation to clinical outcome using several laboratory markers including serum IFX trough levels in patients with CD undergoing scheduled IFX maintenance treatment.

MATERIALS AND METHODS

A total of 78 sessions of endoscopy were performed on 45 patients with CD. Endoscopic activity was assessed using the modified Rutgeerts scoring system. IFX trough levels and anti-IFX antibodies (ATIs) were determined by immunoassays.

RESULTS

Endoscopic activity negatively correlated with serum IFX trough levels (Spearman's rank correlation coefficient (ρ) = -0.54, P < 0.0001) and serum albumin levels (ρ = -0.46, P < 0.0001), and positively correlated with CRP (C-reactive protein) levels (ρ = 0.55, P < 0.0001), ESR (erythrocyte sedimentation rate) (ρ = 0.47, P < 0.0001) and fecal calprotectin levels. IFX trough levels and serum albumin levels were significantly elevated in the mucosal healing (MH) group, but ATIs, CRP, ESR and fecal calprotectin levels were significantly elevated in the nonmucosal healing group. Receiver operation curve revealed that the optimal cutoff value of IFX trough levels for identifying normal laboratory markers was 0.6 μg/ml for CRP, 1.0 μg/ml for serum albumin and 1.1 μg/ml for fecal calprotectin. Identification of mucosal healing needed a higher cutoff value of 4.0 μg/ml. Thiopurine treatment did not affect IFX trough and ATI levels.

CONCLUSION

Mucosal healing requires higher IFX trough levels, compared to those to achieve normalization of routine clinical markers.

TNF blocking therapies and immunomonitoring in patients with inflammatory bowel disease

Since their appearance in the armamentarium for inflammatory bowel disease (IBD) more than a decade ago, antitumor necrosis factor (TNF) inhibitors have demonstrated beneficial activity in induction and maintenance of clinical remission, mucosal healing, improvement in quality of life, and reduction in surgeries and hospitalizations. However, more than one-third of patients present primary resistance, and another one-third become resistant over time. One of the main factors associated with loss of response is the immunogenicity of anti-TNF biologics leading to the production of antidrug antibodies (ADAbs) accelerating their clearance. In this review we present the current state of the literature on the place of TNF and its blockage in the treatment of patients with IBD and discuss the usefulness of serum trough levels and ADAb monitoring in the optimization of anti-TNF therapies.

Comparison of techniques for monitoring infliximab and antibodies against infliximab in Crohn's disease

BACKGROUND

Several techniques are used to measure infliximab (IFX) and anti-IFX antibodies (Abs) in Crohn's disease. The aim of this study was to compare different assays for this purpose.

METHODS

Fluid-phase radioimmunoassay (RIA), solid-phase enzyme-linked immunosorbent assay (ELISA), reporter gene assay (RGA), and enzyme immunoassay (EIA; anti-IFX Ab only) were assessed. IFX was added to pooled serum from 13 patients with inactive Crohn's disease to yield concentrations of 0, 1, 3, and 9 µg/mL. Anti-IFX Abs were assessed in 6 patients.

RESULTS

IFX assessments: RIA and RGA had lower limit of detection than ELISA (0.07 µg/mL and 0.13 versus 0.26). Maximal inaccuracies were 39%, 24%, and 23%. Imprecisions (coefficients of variation) were ≤20% within IFX concentrations between 1 and 9 µg/mL. All assays showed linear correlations (R = 0.97-0.99), but sample concentrations differed by up to 1.55 µg/mL for RIA and RGA, 1.41 µg/mL for ELISA and RIA, and 0.48 µg/mL for ELISA and RGA (P < 0.05). Anti-IFX Ab assessments: RGA gave highly reproducible results (coefficients of variation ≤ 7%) compared with all others (24%-26%). All assays had linear correlations (R = 0.71-0.93), except ELISA versus RGA and EIA. Assays disagreed on anti-IFX Ab titers with mean difference -420 (-1200 to 210) in RGA and EIA, and up to 4500 (-2700 to 11,800) in RIA and RGA. A contributing factor to these discrepancies was inability of ELISA to detect IgG4 anti-IFX Abs.

CONCLUSIONS

Performances of assays for IFX and anti-IFX Abs are comparable. However, IFX concentrations and anti-IFX Ab titers show systematic differences, and in individual patients, only the same assay should be used. Problems may arise when different assays are used to manage therapies in the same patient.

When combination therapy isn’t working: Emerging therapies for the management of inflammatory bowel disease

Although antagonists of tumor necrosis factor have resulted in major therapeutic benefits in inflammatory bowel disease, the magnitude and durability of response are variable. Similar to previously available drugs such as 5-aminosalicylates and immunomodulators, the therapeutic effect is not universal leaving many people searching for options. The development of newer agents has benefited from advances in the understanding of the pathophysiology of the disease. Uncontrolled activation of the acquired immune system has an important role, and lymphocytes, cytokines, and adhesion molecules are broadly targeted for therapeutic intervention. There is increasing evidence of an important role of the innate immune system and the intestinal epithelium, and the therapeutic paradigm is also shifting from immunosuppression to the reinforcement of the intestinal barrier, and modification of the disease process. In this review, we explore the limitation of current therapy as well as mechanisms of actions of new drugs and the efficacy and adverse events from data from clinical trials.

Role of capsule endoscopy in inflammatory bowel disease

Videocapsule endoscopy (VCE) has revolutionized our ability to visualize the small bowel mucosa. This modality is a valuable tool for the diagnosis of obscure small bowel Crohn’s disease (CD), and can also be used for monitoring of disease activity in patients with established small-bowel CD, detection of complications such as obscure bleeding and neoplasms, evaluation of response to anti-inflammatory treatment and postoperative recurrence following small bowel resection. VCE could also be an important tool in the management of patients with unclassified inflammatory bowel disease, potentially resulting in reclassification of these patients as having CD. Reports on postoperative monitoring and evaluation of patients with ileal pouch-anal anastomosis who have developed pouchitis have recenty been published. Monitoring of colonic inflammatory activity in patients with ulcerative colitis using the recently developed colonic capsule has also been reported. Capsule endoscopy is associated with an excellent safety profile. Although retention risk is increased in patients with small bowel CD, this risk can be significanty decreased by a routine utilization of a dissolvable patency capsule preceding the ingestion of the diagnostic capsule. This paper contains an overview of the current and future clinical applications of capsule endoscopy in inflammatory bowel disease.

Therapy with stem cells in inflammatory bowel disease

Inflammatory bowel disease (IBD) affects a part of the young population and has a strong impact upon quality of life. The underlying etiology is not known, and the existing treatments are not curative. Furthermore, a significant percentage of patients are refractory to therapy. In recent years there have been great advances in our knowledge of stem cells and their therapeutic applications. In this context, autologous hematopoietic stem cell transplantation (HSCT) has been used in application to severe refractory Crohn’s disease (CD), with encouraging results. Allogenic HSCT would correct the genetic defects of the immune system, but is currently not accepted for the treatment of IBD because of its considerable risks. Mesenchymal stem cells (MSCs) have immune regulatory and regenerative properties, and low immunogenicity (both autologous and allogenic MSCs). Based on these properties, MSCs have been used via the systemic route in IBD with promising results, though it is still too soon to draw firm conclusions. Their local administration in perianal CD is the field where most progress has been made in recent years, with encouraging results. The next few years will be decisive for defining the role of such therapy in the management of IBD.

Gut microbiome composition and function in experimental colitis during active disease and treatment-induced remission

Dysregulated immune responses to gut microbes are central to inflammatory bowel disease (IBD), and gut microbial activity can fuel chronic inflammation. Examining how IBD-directed therapies influence gut microbiomes may identify microbial community features integral to mitigating disease and maintaining health. However, IBD patients often receive multiple treatments during disease flares, confounding such analyses. Preclinical models of IBD with well-defined disease courses and opportunities for controlled treatment exposures provide a valuable solution. Here, we surveyed the gut microbiome of the T-bet(-/-) Rag2(-/-) mouse model of colitis during active disease and treatment-induced remission. Microbial features modified among these conditions included altered potential for carbohydrate and energy metabolism and bacterial pathogenesis, specifically cell motility and signal transduction pathways. We also observed an increased capacity for xenobiotics metabolism, including benzoate degradation, a pathway linking host adrenergic stress with enhanced bacterial virulence, and found decreased levels of fecal dopamine in active colitis. When transferred to gnotobiotic mice, gut microbiomes from mice with active disease versus treatment-induced remission elicited varying degrees of colitis. Thus, our study provides insight into specific microbial clades and pathways associated with health, active disease and treatment interventions in a mouse model of colitis.

Involvement of IL-23 in enteropathic arthritis patients with inflammatory bowel disease: preliminary results

The role of interleukin (IL)-23 in the pathogenesis of inflammatory bowel disease (IBD) remains unclear. The aim of this work was to study the serum level of IL-23 in IBD with and without arthritis and determine its relation to the subsets and clinical features of the disease. Thirty-seven patients with IBD including 11 with arthritis were included in the study with a mean age of 30.86 ± 4.66 years. Twenty healthy subjects served as control. Seronegative spondyloarthropathy was present in 11 (29.73 %) of the IBD patients; Crohn's disease (CD) was present in 23 and 14 had ulcerative colitis (UC). Serum level of IL-23 was measured in all patients and control by ELISA. IL-23 was significantly higher in IBD patients (46.24 ± 27.19 pg/ml) compared to control (24.1 ± 2.31 pg/ml) (p < 0.0001) being higher in CD patients (52.57 ± 32.78 pg/ml) compared to those with UC (35.86 ± 6.41 pg/ml) (p = 0.026). Furthermore, it was significantly higher in those with peripheral and/or axial arthritis (67.73 ± 40.85 pg/ml) compared to patients without (37.15 ± 10.37 pg/ml) (p = 0.03). There was a tendency to a higher level in males (49.15 ± 30.97 pg/ml) compared to females (38.4 ± 9.54 pg/ml). Serum IL-23 is increased in IBD especially those with CD associated with arthritis and sacroiliitis. The IL-23 could be added to the biomarkers of development of arthritis in IBD patients. These results also confirm the findings of previous studies on the critical role played by IL-23 in the pathogenesis of IBD making it an important new therapeutic target for these patients.

Clinical utility of newly developed immunoassays for serum concentrations of adalimumab and anti-adalimumab antibodies in patients with Crohn's disease

BACKGROUND/AIM

The appearance of anti-adalimumab antibodies (AAAs) is associated with low serum adalimumab (ADA) trough levels and a decrease of clinical response. The goal of this study was to assess the accuracy and clinical utility of new immunoassays for serum ADA and AAA levels.

PATIENTS AND METHODS

Serum ADA trough levels and AAA levels were measured using new immunoassays in 40 patients with Crohn's disease (CD) receiving ADA maintenance therapy.

RESULTS

Serum ADA trough levels were 12.3 ± 9.6 μg/ml (n = 40) in CD patients, and 14 of 40 patients (35 %) were positive for AAAs. A negative correlation was observed between serum AAA levels and ADA trough levels (y = -6.02x + 18.7, r = -0.54, P < 0.001, n = 40). The ROC (receiver-operator curve) analyses indicated that an ADA trough of 5.9 μg/ml was optimal to maintain negative CRP (C-reactive protein) levels (≤0.3 mg/dl). The ADA trough levels were significantly lower in patients positive for AAAs (5.5 ± 5.4 μg/ml, n = 14) than in patients negative for AAAs (16.0 ± 9.5 μg/ml, n = 26). The CRP and ESR levels were significantly higher in AAA-positive patients than in AAA-negative patients. Serum albumin levels were significantly lower in AAA-positive patients. The positive rate for AAAs in patients who lost a response to infliximab (50 %) was significantly higher than that of anti-TNF-α drug naïve patients (12.5 %).

CONCLUSIONS

These new assays for serum AAA trough and AAA levels are useful for routine clinical use and may help guide selection of optimal management strategies for IBD patients with a loss of response to ADA.

The incidence and predictors of lupus-like reaction in patients with IBD treated with anti-TNF therapies

BACKGROUND

The incidence of lupus-like reactions (LLRs) in patients with inflammatory bowel disease (IBD) treated with anti-tumor necrosis factor (ATNF) has not been well defined. We aimed to characterize the features and predictors associated with LLR.

METHODS

We studied a cohort of adult patients with IBD treated with ATNF by a single specialist during 2009. Patients with LLR were characterized and compared with those without LLR for possible predictors.

RESULTS

Twenty of 289 patients (6.9%) had LLR (19.9 cases per 1000 patient-years). Female gender and IBD-unclassified were more prevalent in the LLR group (85% versus 54%, P = 0.009; and 15% versus 2.2%, P = 0.018, respectively), with a hazard ratio of 3.89 (95% confidence interval = 1.12-13.55; P = 0.033) and 7.38 (95% confidence interval = 1.93-28.23; P = 0.003), respectively. ATNF duration was shorter in the LLR group (median, 1 year [interquartile range, 0-3] versus 3 years [interquartile range, 1-6.5], P = 0.005). Arthropathy was universal, followed by fatigue and dermatitis (30% each). Antinuclear antibodies were universally positive, and 16 of 20 had anti-double-stranded DNA. ATNF was discontinued in all; 8 patients required corticosteroids and 1 required hydroxychloroquine followed by complete clinical resolution (mean 7.9 ± 5.9 months). Antinuclear antibodies reverted or normalized in 7 of 16 patients (44%). Fourteen patients (70%) were switched to a second ATNF, 2 with concomitant immunomodulators, and 12 as monotherapy. One patient on ATNF monotherapy developed a second LLR and was successfully switched to a third ATNF.

CONCLUSION

LLRs secondary to ATNFs are more frequent than previously reported, more common in women and IBD-unclassified. It is reversible with cessation of the culprit agent and steroids. Switching to an alternative ATNF rarely results in recurrence.

Personalised treatment using serum drug levels of adalimumab in patients with rheumatoid arthritis: an evaluation of costs and effects

OBJECTIVE

To evaluate the cost-effectiveness of personalised treatment for rheumatoid arthritis (RA) using clinical response and serum adalimumab levels.

METHODS

A personalised treatment algorithm defined, based on clinical (European League Against Rheumatism) response and drug levels at 6 months, whether adalimumab treatment should be continued in a specific dose or discontinued and/or switched to a next biological. Outcomes were simulated using a patient level Markov model, with 3 months cycles, based on a cohort of 272 adalimumab-treated patients with RA for 3 years and data of patients from the Utrecht Rheumatoid Arthritis Cohort. Costs, clinical effectiveness and quality adjusted life years (QALYs) were compared with outcomes as observed in usual care and incremental cost-effectiveness ratios were calculated. Analyses were performed probabilistically.

RESULTS

Clinical effectiveness was higher for the cohort simulated to receive personalised care compared with usual care; the average difference in QALYs was 3.84 (95 percentile range -8.39 to 16.20). Costs were saved on drugs: €2 314 354. Testing costs amounted to €10 872. Mean total savings were €2 561 648 (95 percentile range -3 252 529 to -1 898 087), resulting in an incremental cost-effectiveness ratio of €666 500 or €646 266 saved per QALY gained from a societal or healthcare perspective, respectively. In 72% of simulations personalised care saved costs and resulted in more QALYs, in 28% it was cost saving with lower QALYs. Scenario analyses showed cost saving along with QALYs gain or limited loss.

CONCLUSIONS

Tailoring biological treatment to individual patients with RA starting adalimumab using drug levels and short-term outcome is cost-effective. Results underscore the potential merit of personalised biological treatment in RA.

Serum protein profile of Crohn's disease treated with infliximab

The infliximab (IFX) has dramatically improved the treatment of Crohn's disease (CD). However, the need for predictive factors, indicative of patients' response to IFX, has yet to be met. In the current study, proteomics technologies were employed in order to monitor for differences in protein expression in a cohort of patients following IFX administration, aiming at identifying a panel of candidate protein biomarkers of CD, symptomatic of response to treatment. We enrolled 18 patients, who either had achieved clinical and serological remission (Rm, n=6), or response (Rs, n=6) and/or were PNRs (n=6), to IFX. Serum samples were subjected to two-dimensional Gel Electrophoresis. Following evaluation of densitometrical data, protein spots exhibiting differential expression among the groups, were further characterized by MALDI-TOF-MS. Identified proteins where evaluated by immunoblot analysis while functional network association was carried out to asses significance. Proteins apolipoprotein A-I (APOA1), apolipoprotein E (APOE), complement C4-B (CO4B), plasminogen (PLMN), serotransferrin (TRFE), beta-2-glycoprotein 1 (APOH), and clusterin (CLUS) were found to be up-regulated in the PNR and Rs groups whereas their levels displayed no changes in the Rm group when compared to baseline samples. Additionally, leucine-rich alpha-2-glycoprotein (A2GL), vitamin D-binding protein (VTDB), alpha-1B-glycoprotein (A1BG) and complement C1r subcomponent (C1R) were significantly increased in the serum of the Rm group. Through the incorporation of proteomics technologies, novel serum marker-molecules demonstrating high sensitivity and specificity are introduced, hence offering an innovative approach regarding the evaluation of CD patients' response to IFX therapy.

A systematic review of economic studies on biological agents used to treat Crohn's disease

BACKGROUND

Identifying clinical scenarios that maximize the cost-effectiveness of biological treatments can lead to optimized health care cost-saving and clinical effectiveness from a society's perspective.

METHODS

Published articles between January 1995 and June 2012 were searched in PubMed, EMBASE, ABI/INFORM, Tuft's Cost-Effectiveness Analysis Registry Database, Cochrane National Health Service Economic Evaluation Database, International Pharmaceutical Abstracts, Web of Science, and Google Scholar. Studies of interest included the following: (1) cost studies, (2) economic evaluations, or (3) narrative or systematic reviews related to economic evaluations of biological treatments for moderate-to-severe Crohn's disease (CD). The primary outcomes of interest included costs associated with biological treatments and cost-effectiveness measures, including incremental cost-effectiveness ratios. A threshold of $100,000/quality-adjusted life year (£60,000/quality-adjusted life year) gained was used for treatment cost-effectiveness.

RESULTS

Thirty-eight studies were identified, including 15 economic evaluations and 23 cost studies or reviews of economic evaluations. Economic evaluations found that infliximab and adalimumab were more cost-effective than standard therapy for luminal CD when provided as an induction therapy followed by episodic therapy over 5 or more years. The cost-effectiveness of infliximab and adalimumab versus standard therapy for luminal CD was less certain when used as 1-year maintenance treatment with or without previous induction therapy. Cost studies revealed that infliximab therapy reduced health care resource utilization and cost. Older reviews were inconclusive about the cost-effectiveness of biological treatments used for CD.

CONCLUSIONS

Current evidence suggests that biological treatments may be cost-effective for CD under certain clinical scenarios. Future studies evaluating all biological treatments are needed to compare their respective benefits and costs.

Loss of response to long-term infliximab therapy in children with Crohn's disease

Secondary loss of response (LoR) often precludes further use of infliximab in children with Crohn’s disease. Immunomodulators may reduce the incidence of LoR but their combination with infliximab presents safety concerns. We aimed to determine the long-term durability of infliximab response in paediatric Crohn’s, effect of immunomodulators on LoR, and secondarily the effect of infliximab on growth. We retrospectively audited patients on maintenance infliximab at a single centre. Data included height and weight, Paediatric Crohn’s Disease Activity Index (PCDAI), and immunomodulator use. 71 children (32% female, mean age 14.4 years) had been commenced on maintenance infliximab before July 2011. 89% had been on immunomodulators concurrently with infliximab. LoR occurred in 20 (28%), with a median time to LoR of 4.31 years. LoR was significantly increased in children who did not enter remission (PCDAI ≤ 10) after induction (p < 0.05). LoR occurred more frequently in the 72% who ceased immunomodulators, but this failed to reach statistical significance (p = 0.300). Height and weight SDS improved significantly on infliximab. Infliximab is a durable long-term therapy for paediatric Crohn’s refractory to conventional therapy. A large-magnitude increase in the rate of loss of response after immunomodulator cessation was not observed.

A rapid assay for on-site monitoring of infliximab trough levels: a feasibility study

Monitoring levels of biologicals against tumor necrosis factor (TNF) has been suggested to improve therapeutic outcomes in inflammatory bowel diseases (IBDs). This pilot study describes a rapid lateral flow (LF)-based assay for on-site monitoring of serum trough levels of humanized monoclonal antibody infliximab (IFX). The applied chromatographic method utilizes sequential flows of diluted serum, wash buffer, and an immunoglobulin generic label on LF strips with a Test line comprised of TNF-α. The successive flows permitted enrichment of IFX at the Test line before the label was applied. The label, luminescent upconverting phosphor (UCP) particles coated with protein-A, emits a 550-nm visible light upon excitation with 980-nm infrared light. IFX concentrations were determined through measurement of UCP fluorescence at the Test line. The assay was optimized to detect IFX levels as low as 0.17 μg/mL in serum. For patients with IBD, this limit is appropriate to detect levels associated with loss of response (0.5 μg IFX/mL). The assay was evaluated with clinical samples from patients with Crohn's disease and correlated well within the physiologically relevant range from 0.17 to 10 μg/mL with an IFX-specific ELISA. Performance of the assay was further successfully validated with samples from blood donors, IFX negative IBD patients, and rheumatoid arthritis patients that had developed anti-IFX antibodies. Because of its generic nature, the assay is suited for detecting most therapeutic anti-TNF-α monoclonal antibodies.

Optimizing anti-TNF treatments in inflammatory bowel disease

BACKGROUND

Failure of anti-TNF treatment in inflammatory bowel disease (IBD) patients can take on several forms, each posing distinct etio-pathogenic considerations and management dilemmas.

AIM

The aim of this study is to review the mechanisms responsible for the various forms of anti-TNF failures in IBD and to elucidate strategies for optimizing clinical efficacy.

RESULTS

Primary failures of anti-TNF induction therapy occur in up to 40% of patients in clinical trials and in 10-20% in clinical series. Longer disease duration, smoking and several genetic mutations are predisposing factors for primary failures. Curiously, primary non-response is probably not a class-effect phenomenon since switching to another anti-TNF is effective in over 50% of such patients. Secondary loss of response is also a common clinical problem with incidence ranging between 23 and 46% at 12months after anti-TNF initiation. Underlying mechanisms are often related to increased anti-TNF clearance by anti-drug antibodies, but may also include other causes for recalcitrant IBD activity as well as disorders that are unrelated to IBD itself. Astute management begins with verifying the presence of uncontrolled inflammatory IBD activity as a cause for patient's symptoms. Next, it is prudent to consider a trial of wait-and-see approach, since in some patients with mild-moderate symptoms, loss of response may resolve without alteration of therapy. If it does not, measuring anti-TNF trough levels and anti-drug antibodies may clarify the underlying mechanism in individual patients although there are still limited and conflicting data regarding the role of these measurements in guiding the choice between dose-intensification, switch to another anti-TNF or to another immuno-modulator, and the addition of an immuno-modulator as a combination therapy with the failing anti-TNF. Anti-TNF re-induction after prior drug-holiday is a distinct clinical scenario and scarce evidence suggests re-induction outcome to be dependent on the circumstances when drug-holiday was commenced. Finally, discontinuation of anti-TNF in patients with stable deep clinico-biologic and mucosal remission may be a viable option, as in these carefully selected patients the majority may enjoy long-term remission without the need for continued anti-TNF treatment.

Top-down or step-up treatment in Crohn's disease?

In recent years, a change in the treatment goals for patients with Crohn's disease (CD) has come under intense discussion. Whereas 10 years ago treatment was initiated mainly in reaction to acute flares of the disease aimed to improve clinical symptoms, the focus now has changed to the prevention of damage to the intestinal wall. The prevention of structural damage by achievement of 'mucosal healing', however, is associated with the more 'aggressive' treatment and an earlier use of immunosuppressants and biologicals. The use of immunosuppressants and biologicals especially in patients with CD has decreased the rates of surgery and hospitalizations, indicating that there is a group of patients definitely profiting from such an early use of immunosuppressive treatment. In this group of patients, the benefits outweigh the disadvantages of immunosuppression: the increased risk of severe infections. However, it remains questionable whether this improvement can only be achieved by completely reversing established treatment strategies. The dispute has been condensed to the questions whether 'top-down' (e.g. start with a combination of biological and immunosuppressant and 'de-escalate' if possible) or 'step-up' treatment (e.g. start with topical steroids, step up to systemic steroid, go to immunosuppression and biologicals if necessary) may be better. In general, in an upcoming era of individualized and personalized medicine, a 'one-size-fits-all' approach does not appear to be desirable. CD patients definitely should not be undertreated (which is still frequently the case) or remain on steroid treatment (which is inappropriate); however, overtreatment (putting patients at risk of side effects without benefit) is against a fundamental principle of medicine: nihil nocere (do no harm).

Treatment of inflammatory bowel disease by chemokine receptor-targeted leukapheresis

Leukapheresis removes circulating leukocytes en route to the target organ. Hitherto unspecific matrixes have been used to remove leukocytes in inflammatory bowel disease (IBD). This report describes a novel selective leukapheresis column based on chemokine-chemokine receptor interaction. We found an increased expression of the gut homing chemokine receptor CCR9 on CD14(+) monocytes and on CD3(+) T lymphocytes from IBD patients. Biologically active CCL25 was coupled to a Sepharose matrix and demonstrated to selectively remove CCR9-expressing cells leaving other cell populations largely unaffected. A patient with active ulcerative colitis, was subjected to CCL25-column leukapheresis. Four days after treatment, he experienced clinical improvement and stable disease improvement ensued. The study illustrates that specific cells can be targeted using high affinity interactions, i.e., CCL25-CCR9 interactions to remove pathogenic gut-homing cells. Leukapheresis using the bCCL25 column should be investigated in a clinical phase I trial of patients with inflammatory bowel disease.

Serum adalimumab concentration and clinical remission in patients with Crohn's disease

BACKGROUND

Drug concentration monitoring may be useful to guide therapeutic adjustments for anti-tumor necrosis factor agents in Crohn's disease. The relationship between serum adalimumab concentrations and clinical outcomes was assessed using data from CLinical Assessment of Adalimumab Safety and Efficacy Studied as Induction Therapy in Crohn's Disease (CLASSIC) I/II.

METHODS

Serum adalimumab concentrations at week 4 of CLASSIC I and weeks 4, 24, and 56 of CLASSIC II were compared by clinical remission status (yes/no). Logistic regression and Classification and Regression Tree analyses explored factors associated with remission at weeks 4, 24, and 56. Threshold analyses and receiver operating characteristic curves evaluated the relationship between serum concentrations and clinical remission/response.

RESULTS

Serum adalimumab concentrations for 275 patients were available. Median adalimumab concentrations were significantly higher in patients who achieved clinical remission than those who did not at week 4 of CLASSIC I (8.10 versus 5.05 µg/mL, P < 0.05). At all time points, adalimumab concentrations demonstrated considerable variability and overlap between patients with and without remission. With Classification and Regression Tree analyses, baseline Crohn's Disease Activity Index, baseline C-reactive protein, and adalimumab concentrations were associated with early remission at week 4 of CLASSIC I and week 4 of CLASSIC II, but not at weeks 24 and 56. Receiver operating characteristic curves demonstrated low utility of cutoff thresholds to discriminate by clinical response/remission status.

CONCLUSIONS

A positive association between serum adalimumab concentration and remission was identified at several time points. A threshold concentration reliably associated with remission was not identified. Further prospective evaluations are needed before recommendations for adalimumab concentration monitoring can be made.

Addition of an immunomodulator to infliximab therapy eliminates antidrug antibodies in serum and restores clinical response of patients with inflammatory bowel disease

There are few therapeutic options for patients with inflammatory bowel disease who lose response to infliximab because they produced antibodies against the drug. We performed a retrospective analysis to investigate whether administration of immune modulators to 5 patients who developed antibodies to infliximab (ATI) restored response to this drug; 3 patients were given azathioprine/6-mercaptopurine and 2 patients were given methotrexate. Concentrations of infliximab and ATIs, and antitumor necrosis factor (TNF) activity, were analyzed using enzyme-linked immunosorbent assay-based competition assays of serum samples collected before and after patients were given the immunomodulator. In all patients, levels of ATIs gradually decreased and trough levels of infliximab increased; clinical responses were restored to all patients. In competition assays, immunomodulator-induced elimination of ATIs was associated with increased anti-TNF activity in serum. The addition of immunomodulators to therapy might be helpful to patients who have lost response to anti-TNF agents owing to formation of antidrug antibodies.

Serum infliximab concentrations in pediatric inflammatory bowel disease

OBJECTIVE

To study serum infliximab (s-IFX) levels in pediatric patients with inflammatory bowel disease (IBD).

SUBJECTS AND METHODS

s-IFX trough levels were measured in a total of 133 blood samples of 37 pediatric IBD patients (Crohn's disease, 23): 48 during the induction phase (weeks 2 and 6) and 85 during maintenance treatment. Antibodies to infliximab (ATI) were determined in 93 samples (30 patients). s-IFX values were related to fecal calprotectin (FC) and serum markers of inflammation.

RESULTS

During induction (5 mg/kg) and maintenance therapy, the median s-IFX levels were 17.6 μg/ml (range 0-48 μg/ml) and 3.55 μg/ml (range 0-40 μg/ml), respectively. The IFX levels were similar in ulcerative colitis and Crohn's disease (e.g. during maintenance median 3.2 vs. 2.8 μg/ml, p = 0.718), thus the data are pooled. During induction, the s-IFX level was associated with the total dose of IFX, that is, young children with lower body weight had lower levels (p < 0.001 at week 2 and p < 0.05 at week 6). Shorter administration interval resulted in higher trough levels (p < 0.005). All samples with undetectable s-IFX (6.8%) levels presented ATI. High inflammation (FC >1000 µg/g) during induction was associated with lower s-IFX levels (median 4.0 μg/ml, range 0.47-25 compared to median 20 μg/ml, range 0-48 when FC <1000 µg/g, p < 0.005). There was no significant association between the ESR or values of C-reactive protein and s-IFX levels during induction.

CONCLUSIONS

In pediatric IBD, lower body weight and higher level of intestinal inflammation are associated to s-IFX levels during induction but relation to therapeutic response is unclear.

Impact of antibodies to infliximab on clinical outcomes and serum infliximab levels in patients with inflammatory bowel disease (IBD): a meta-analysis

OBJECTIVES

Antibodies to infliximab (ATIs) have been associated with loss of clinical response and lower serum infliximab (IFX) levels in some studies of patients with inflammatory bowel disease (IBD). This has important implications for patient management and development of novel biologic therapies. The objective of this study was to perform a systematic review and meta-analysis of studies that reported clinical outcomes and IFX levels according to patients' ATI status.

METHODS

MEDLINE, Web of Science, CINAHL, Scopus, and EMBASE were searched for eligible studies. Quality assessment was undertaken using GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. Raw data from studies meeting inclusion criteria was pooled for meta-analysis of effect estimates. Sensitivity analysis was performed for all outcomes. Funnel plot was performed to assess for publication bias.

RESULTS

Thirteen studies met the inclusion criteria, and reported results in 1,378 patients with IBD. All included studies had a high risk of bias in at least one quality domain. The pooled risk ratio (RR) of loss of clinical response to IFX in patients with IBD who had ATIs was 3.2 (95% confidence interval (CI): 2.0-4.9, P<0.0001), when compared with patients without ATIs. This effect estimate was predominantly based on data from patients (N=494) with Crohn's disease (RR: 3.2, 95% CI: 1.9-5.5, P<0.0001). Data only from patients with ulcerative colitis (n=86) exhibited a non-significant RR of loss of response of 2.2 (95% CI: 0.5-9.0, P=0.3) in those with ATIs. Heterogeneity existed between studies, in both methods of ATI detection, and clinical outcomes reported. Three studies (n=243) reported trough serum IFX levels according to ATI status; the standardized mean difference in trough serum IFX levels between groups was -0.8 (95% CI -1.2, -0.4, P<0.0001). A funnel plot suggested the presence of publication bias.

CONCLUSIONS

The presence of ATIs is associated with a significantly higher risk of loss of clinical response to IFX and lower serum IFX levels in patients with IBD. Published studies on this topic lack uniform reporting of outcomes. High risk of bias was present in all the included studies.

Clinical implications of variations in anti-infliximab antibody levels in patients with inflammatory bowel disease

BACKGROUND

The aim of the study was to investigate variations in anti-infliximab (IFX) antibody (Ab) levels and clinical implications thereof in patients with inflammatory bowel disease (IBD).

METHODS

A retrospective, explorative, single-center study of patients with IBD who developed anti-IFX Ab and in whom anti-IFX Ab were reassessed.

RESULTS

IFX was administered to 316 patients; anti-IFX Ab was determined in 180 patients and detected in 83 (46%). During ongoing IFX maintenance therapy, anti-IFX Ab disappeared at later reassessment in two-thirds of patients with clinical response after median 4 (3-5) infusions. In contrast, anti-IFX Ab persisted in all patients without clinical response. Anti-IFX Ab appeared pharmacologically active, as IFX levels were high when anti-IFX Ab disappeared (median 3.7 μg/mL, interquartile range [IQR] 2.8-5.5), while undetectable or low when anti-IFX Ab persisted (median 0 μg/mL, IQR 0-0). In 56 patients, anti-IFX Ab were assessed after IFX discontinuation. The proportion of patients with anti-IFX Ab gradually declined over time, with a few patients having anti-IFX Ab up to about 4 years after initial assessment. No variables were associated with anti-IFX Ab disappearance in multivariate analysis.

CONCLUSIONS

Discontinuation of IFX is advisable in patients with inadequate response and repeat positive anti-IFX Ab measurements. Anti-IFX Ab can persist for years after discontinuation, which could impact efficacy and safety at retreatment. Continued IFX treatment may, however, be considered in patients with clinical response and a single positive anti-IFX Ab measurement, as anti-IFX Ab disappears in two-thirds of these during continued treatment.

Anti-TNF-α biotherapies: perspectives for evidence-based personalized medicine

This article discusses the rationale behind recommending immunopharmacological guidance of long-term therapies with genetically engineered anti-TNF-α immunoglobulin constructs. Arguments why therapeutic decision-making should not rely on clinical outcome alone are presented. Central to this is that the use of theranostics (i.e., monitoring circulating levels of functional anti-TNF-α drugs and antidrug antibodies) would markedly improve treatment because therapies can be tailored to individual patients and provide more effective and economical long-term therapies with minimal risk of side effects. Large-scale immunopharmacological knowledge of how patients ‘handle’ TNF-α biopharmaceuticals would also help industry develop more effective and safer TNF-α inhibitors.

18F-FDG positron emission tomography: potential utility in the assessment of Crohn's disease

Computed Tomography Enterography (CTE) and Magnetic Resonance Enterography (MRE) are currently the dominant imaging tests used in the assessment of patients with Crohn's disease. More recently, the possibility of utilizing F-18 fluorodeoxyglucose (18F-FDG) Positron Emission Tomography (PET) or PET/CT has been explored in several preliminary studies. 18F-FDG PET appears to enable reliable detection of moderate to severe inflammation in bowel segments involved by Crohn's disease. Perhaps more importantly, 18F-FDG PET has the potential to provide a noninvasive, quantitative measure of inflammation that dynamically reflects changes in Crohn's disease activity. If 18F-FDG PET proves useful in monitoring responses to medical therapy within a few days of therapy initiation, an important new role for imaging in the management of patients with Crohn's disease could emerge.

Genetic polymorphisms of tumour necrosis factor receptor superfamily 1b and fas ligand are associated with clinical efficacy and/or acute severe infusion reactions to infliximab in Crohn's disease

BACKGROUND

Single nucleotide polymorphisms (SNPs) in TNF receptor superfamily (TNFRSF) 1A and 1B, and Fas ligand (FASLG) genes, have been associated with responsiveness to infliximab (IFX) in Crohn's disease.

AIM

To investigate if SNPs in TNFRSF1A and 1B, and FAS (TNFRSF6) and FASLG (TNFSF6), associated with short- or long-term clinical and biological efficacy and with acute severe infusion reactions.

METHODS

Observational, retrospective and explorative cohort study of IFX-treated Caucasian patients with Crohn's disease classified as primary nonresponders (n = 21), response failures on maintenance therapy (n = 37), maintained remission (n = 47) and occurrence of acute severe infusion reactions (n = 20).

RESULTS

During IFX maintenance therapy, minor allele carriage of TNFRSF1B, rs976881 is associated with loss of response [OR 3.3 (1.2-9.1), P = 0.014]. Minor allele homozygosity increased the risk substantially (OR estimated 19, P = 0.006), and furthermore associated with a mean CRP increase of 17 mg/L as compared to a mean decrease of 17 mg/L in all others (P = 0.036). In contrast, minor allele carriage of TNFRSF1B, rs1061622 is associated with beneficial response to IFX induction [OR 4.2 (1.2-18.2), P = 0.014], and with persistence of remission during maintenance therapy [OR 5.5 (1.5-25.5), P = 0.007]. Carriage of the minor allele of FASLG, rs76110 increased risk of severe infusion reactions [OR 4.0 (1.1-22.4), P = 0.041]; minor allele carriage of TNFRSF1B, rs652625 decreased the risk (OR estimated 0.2, P = 0.043 ).

CONCLUSIONS

The TNFRSF1B polymorphisms may contribute to predict efficacy of infliximab. Moreover, FASLG and TNFRSF1B polymorphisms may confer genetic susceptibility to severe infusion reactions. These findings could potentially aid clinical decisions if confirmed in larger studies.

Use of the tumor necrosis factor-blockers for Crohn's disease

The use of anti-tumor necrosis factor-α therapy for inflammatory bowel disease represents the most important advance in the care of these patients since the publication of the National Co-operative Crohn's disease study thirty years ago. The recommendations of numerous consensus groups worldwide are now supported by a wealth of clinical trials and several meta-analyses. In general, it is suggested that tumor necrosis factor-α blockers (TNFBs) are indicated (1) for persons with moderately-severe Crohn's disease or ulcerative colitis (UC) who have failed two or more causes of glucocorticosteroids and an acceptably long cause (8 wk to 12 wk) of an immune modulator such as azathioprine or methotrexate; (2) non-responsive perianal disease; and (3) severe UC not responding to a 3-d to 5-d course of steroids. Once TNFBs have been introduced and the patient is responsive, therapy given by the IV and SC rate must be continued. It remains open to definitive evidence if concomitant immune modulators are required with TNFB maintenance therapy, and when or if TNFB may be weaned and discontinued. The supportive evidence from a single study on the role of early versus later introduction of TNFB in the course of a patient's illness needs to be confirmed. The risk/benefit profile of TNFB appears to be acceptable as long as the patient is immunized and tested for tuberculosis and viral hepatitis before the initiation of TNFB, and as long as the long-term adverse effects on the development of lymphoma and other tumors do not prone to be problematic. Because the rates of benefits to TNFB are modest from a population perspective and the cost of therapy is very high, the ultimate application of use of TNFBs will likely be established by cost/benefit studies.

Infliximab modifies mesenteric adipose tissue alterations and intestinal inflammation in rats with TNBS-induced colitis

OBJECTIVE

Infliximab is a monoclonal anti-TNF-α antibody that is used therapeutically to treat Crohn's disease (CD). High levels of pro-inflammatory cytokines, especially TNF-α, have been observed in the gastrointestinal tract of CD patients and were associated with alterations in the mesenteric adipose tissue, which also contributed to the high levels of adipokine release. The authors used a rat model of colitis that produces mesenteric adipose tissue alterations that are associated with intestinal inflammation to study the effects that infliximab treatment has on adipokine production, morphological alterations in adipose tissue and intestinal inflammation.

MATERIAL AND METHODS

The ability of infliximab to neutralize rat TNF-α was evaluated in vitro using U937 cells. Colitis was induced by repeated intracolonic trinitrobenzene sulfonic acid instillations and was evaluated by macroscopic score, histopathological analysis, myeloperoxidase activity, TNF-α and IL-10 expression as well as iNOS (inducible NO synthase) expression and JNK phosphorylation in colon samples. The alterations in adipose tissue were assessed by TNF-α, IL-10, leptin, adiponectin and resistin levels as well as adipocyte size and peroxisome proliferator-activated receptor (PPAR)-γ expression.

RESULTS

Infliximab treatment controlled intestinal inflammation, which reduced lesions and neutrophil infiltration. Inflammatory markers, such as iNOS expression and JNK phosphorylation, were also reduced. In mesenteric adipose tissue, infliximab increased the production of IL-10 and resistin, which was associated with the restoration of adipocyte morphology and PPAR-γ expression.

CONCLUSIONS

Our results suggest that infliximab could contribute to the control of intestinal inflammation by modifying adipokine production by mesenteric adipose tissue.

What to take from TREAT?

The TREAT Registry is an updated submission of the 5-year follow-up of Crohn's disease patients from community and academic centers in North America treated with or without infliximab. Over 6,000 patients were followed for risks of mortality and serious infections. Similar to data presented after nearly 2 years of follow-up, mortality was similar for infliximab- and other-treatment-only patients. Infliximab, corticosteroids and narcotics were associated with increased risks of serious infections. Data presented is similar from data reported for controlled trials and observational series in patients with inflammatory bowel disease and rheumatoid arthritis.

A survey of applications of biological products for drug interference of immunogenicity assays

PURPOSE

Biological drugs in circulation can interfere with anti-drug antibody (ADA) assays and cause false ADA negatives. We surveyed the applications of biological products approved by FDA during 2005-2011 for prevalence of drug interferences and proposed approaches to address this issue scientifically.

METHODS

The immunogenicity assay drug tolerance, steady-state drug concentrations, and immunogenicity rates were reviewed for 26 BLA/NDA and 2 sBLA.

RESULTS

Many FDA approved biologics had higher steady-state drug concentrations than the drug tolerance of ADA assays, by 1.2- to 800-fold. Reported immunogenicity rates may be negatively impacted. Some sponsors triaged immunogenicity samples according to the drug tolerance, leaving some samples un-assayed or reporting them as inconclusive ADA; but these samples were interpreted as ADA- for calculating immunogenicity rates.

CONCLUSIONS

Implementation of ADA assays that can tolerate therapeutic drug concentrations is imperative. Given drug interferences, we propose in this paper the following practices: (i) to measure drug concentrations in ADA samples, (ii) to explicitly list all ADA status, including inconclusive ADA and un-assayed samples, (iii) to calculate population immunogenicity rates based on only subjects with confirmed ADA+ and ADA-, and (iv) to make available ADA assay specifics relevant to the use of ADA data in disease management.

Immunogenicity of biological therapeutics: from assay to patient

PURPOSE OF REVIEW

To give an overview of the current knowledge on assay techniques and clinical implications of immunogenicity of biological therapeutics.

RECENT FINDINGS

Assay techniques for the measurement of immunogenicity have improved, expanding the understanding of the immune response against biological therapeutics. Knowledge on the clinical effect of immunogenicity enables the treatment of patients in a targeted fashion, as a step towards personalized medicine.

SUMMARY

Biological medications are able to induce an antidrug immune response. Immunogenicity impairs clinical response and is associated with adverse events. Several confounding factors influence the measurement of immunogenicity, including drug interference and background problems. Concomitant administration of methotrexate lowers the frequency and amount of antibodies formed, whereby the efficacy of biologicals is improved. Algorithms for therapeutic drug monitoring could aid in adapting treatment strategies in a controlled setting.

Pediatric ulcerative colitis: current treatment approaches including role of infliximab

Ulcerative colitis is a chronic inflammatory bowel disease that can lead to derangements in the growth, nutritional status, and psychosocial development of affected children. There are several medical options for the induction and maintenance of disease remission, but the benefits of these medications need to be carefully weighed against the risks, especially in the pediatric population. As the etiology of the disease has become increasingly understood, newer therapeutic alternatives have arisen in the form of biologic therapies, which are monoclonal antibodies targeted to a specific protein or receptor. This review will discuss the classical treatments for children with ulcerative colitis, including 5-aminosalicylates, corticosteroids, thiopurine immunomodulators, and calcineurin inhibitors, with a particular focus on the newer class of anti-tumor necrosis factor-α agents.

Optimizing immunomodulators and anti-TNF agents in the therapy of Crohn disease

Randomized trials support the use of the thiopurines and anti-TNF monoclonal antibodies in treating Crohn disease. New therapeutic approaches and laboratory assays have helped optimize the use of these agents. Thiopurine methyltransferase activity should always be determined to avoid thiopurines in individuals with absent enzyme activity. The role of metabolite-adjusted dosing when initiating thiopurines is not settled. Measuring metabolites helps guide management in patients failing therapy. Loss of response to anti-TNF therapy is mitigated by maintenance therapy and concomitant immunomodulators. When loss of response to infliximab occurs, management is guided by the serum concentrations of infliximab and antibodies to infliximab.

Outcome after discontinuation of infliximab in patients with inflammatory bowel disease in clinical remission: an observational Danish single center study

OBJECTIVE

To investigate duration of remission, including risk factors for relapse and response to retreatment with infliximab (IFX), in patients with Crohn's disease (CD) and ulcerative colitis (UC) who had discontinued IFX while in clinical remission.

METHODS

Observational, single-center, retrospective study of all patients with a primary response to IFX who discontinued IFX therapy while in steroid-free remission. Relapse was defined as reintroduction of treatment with a biologic, systemic steroid or surgery.

RESULTS

Of 219, 53 (24%) CD patients, and 28 of 97 (30%) UC patients discontinued IFX while in clinical steroid-free remission. The proportion of patients in remission declined steadily with 61% of CD patients, and 75% of UC patients being in remission after 1 year. Half the patients maintained remission after median 2 years (680 days (412-948)) and 3.5 years (1334 days (995-1673)), respectively; p = 0.057. Twelve percent with CD and 40% with UC were in remission at the end of follow-up after 10 and 4.5 years, respectively. Longer disease duration was associated with relapse in univariate analysis in CD, OR 1.1 (1.0-1.1), p = 0.022. Of 25, 24 CD patients (96%), and 5 of 7 UC patients (71%) experienced complete clinical remission when retreated with IFX after relapse.

CONCLUSION

While the short-term prognosis seems favorable, the majority of patients who discontinue IFX while in remission relapse over time. The response to retreatment with IFX at relapse seems favorable in this subpopulation.