A randomised phase I study of etrolizumab (rhuMAb β7) in moderate to severe ulcerative colitis

Pharmacokinetic and Pharmacodynamic Modeling of Serum Etrolizumab and Circulating β7 Receptor Occupancy in Patients With Ulcerative Colitis

Etrolizumab, a humanized monoclonal antibody, specifically binds to the β7 subunit of the heterodimeric integrins α4β7 and αEβ7. Pharmacokinetic (PK) and pharmacodynamic (PD) data were collected from an etrolizumab phase 1 trial in patients with moderate to severe ulcerative colitis (UC). We developed a mechanism‐based model to simultaneously describe the kinetics of serum etrolizumab concentration and free β7 receptors on circulating intestinal‐homing CD4⁺ T lymphocytes. Included in the analysis were 38 phase 1 UC patients who received single or 3 monthly doses of etrolizumab intravenously or subcutaneously across a dose range of 0.3 to 10 mg/kg. A quasi–steady‐state target‐mediated drug disposition model was developed to describe the dynamic interaction between serum etrolizumab concentration and free β7 receptors on intestinal‐homing CD4⁺ T lymphocytes in UC patients. The time profiles of serum etrolizumab and absolute counts of β7⁺ lymphocytes (expressed as percentage of baseline level) were well described by the quasi–steady‐state target‐mediated drug disposition model. The model was able to characterize the maximum drug occupancy of β7 receptors on intestinal‐homing CD4⁺ T lymphocytes and the concentration‐dependent duration of occupancy. The 90% effective concentration for etrolizumab to saturate the β7 receptors on intestinal homing CD4⁺ T cells was 1.3 μg/mL. PK and PD profiles predicted by the model were consistent with observations from a subsequent phase 2 study. In conclusion, an integrated PK/PD model developed in this analysis reasonably described serum etrolizumab PK profiles and the relationship between PK and PD (free β7 receptors on circulating intestinal‐homing CD4⁺ T lymphocytes) in UC patients.

Blockade of αEβ7 integrin suppresses accumulation of CD8+ and Th9 lymphocytes from patients with IBD in the inflamed gut in vivo

OBJECTIVE

Therapeutically targeting lymphocyte adhesion is of increasing relevance in IBD. Yet, central aspects of the action of antiadhesion compounds are incompletely understood. We investigated the role of αEβ7 and α4β7 integrins and their blockade by vedolizumab and etrolizumab for trafficking of IBD T lymphocytes in an in vivo model of homing to and retention in the inflamed gut.

DESIGN

We explored integrin expression in patients with IBD by flow cytometry and immunohistochemistry, while regulation of integrins was studied in T cell cultures. The functional relevance of integrins was assessed by adhesion assays and a recently established humanised mouse model in dextran sodium sulfate-treated immunodeficient mice.

RESULTS

High expression of αEβ7 was noted on CD8⁺ and CD4⁺ Th9 cells, while α4β7 was expressed on CD8⁺, Th2 and Th17 cells. T cell receptor stimulation and transforming growth factor β were key inducers of αEβ7 on human T cells, while butyric acid suppressed αEβ7. In comparison to α4β7 blockade via vedolizumab, blockade of β7 via etrolizumab surrogate antibody superiorly reduced colonic numbers of CD8⁺ and Th9 cells in vivo after 3 hours, while no difference was noted after 0.5 hours. AEβ7 expression was higher on CD8⁺ T cells from patients with IBD under vedolizumab therapy.

CONCLUSIONS

AEβ7 is of key relevance for gut trafficking of IBD CD8⁺ T cells and CD4⁺ Th9 cells in vivo and mainly retention might account for this effect. These findings indicate that blockade of αEβ7 in addition to α4β7 may be particularly effective in intestinal disorders with expansion of CD8⁺ and Th9 cells such as IBD.

Placebo response and remission rates in randomised trials of induction and maintenance therapy for ulcerative colitis

BACKGROUND

It is important to minimize placebo rates in randomised controlled trials (RCTs) to efficiently detect treatment differences between interventions. Historically, high placebo rates have been observed in clinical trials of ulcerative colitis (UC). A better understanding of factors influencing placebo rates may lead to more informed clinical trial design.

OBJECTIVES

A systematic review and meta-analysis was conducted to evaluate placebo response and remission rates in RCTs evaluating UC treatments in adult patients.

SEARCH METHODS

Electronic databases (i.e. MEDLINE, EMBASE, and CENTRAL) were searched from inception to 1 March 2017 with no language restrictions applied. Reference lists and conference proceedings of major gastroenterology meetings were also handsearched to identify additional studies.

SELECTION CRITERIA

Placebo-controlled RCTs of adult patients with UC treated with corticosteroids, aminosalicylates, immunosuppressives or biologics were eligible, provided enrolment and outcome assessment was conducted using the Ulcerative Colitis Disease Activity Index (UCDAI) or the Mayo Clinic Score. The minimum trial duration was two weeks for induction trials and four months maintenance trials.

DATA COLLECTION AND ANALYSIS

Pairs of authors independently determined study eligibility and extracted data with any disagreements resolved through consensus. Outcomes of interest included the proportion of patients with clinical response and remission. Trial characteristics such as the design, participant demographics and disease history, interventions, and enrolment and assessment criteria were also recorded. The methodological quality of the included studies was evaluated using the Cochrane risk of bias tool. Pooled placebo response and remission rates and 95% confidence intervals (95% CI) were calculated using a binomial normal model for proportions. Induction of remission and maintenance studies were pooled separately. The impact of study-level characteristics on placebo response and remission rates was investigated using mixed-effects meta-regression analyses with logits of event rates as the outcome variables. An assessment of pooled placebo rates over time was conducted using a cumulative meta-analysis based on date of publication. Publication bias was examined using funnel plots.

MAIN RESULTS

The screening process identified 61 included studies which encompass 58 induction phases (5111 patients randomised to placebo) and 12 maintenance phases (1579 patients randomised to placebo). For induction trials, the pooled estimate of placebo response was 33% (95% CI 30% to 36%) while the pooled estimate of placebo remission was 12% (95% CI 9% to 15%). For maintenance trials, the pooled estimate of placebo response was 23% (95% CI 19% to 28%) while the pooled estimate of placebo remission was 17% (95% CI 10% to 27%).Studies enrolling patients with more active disease confirmed objectively by endoscopy were associated with significantly lower placebo remission and response rates than trials enrolling patients with less active disease (27% versus 4%, OR 2.60, 95% CI 1.25 to 5.42, P = 0.01 for UCDAI endoscopy sub score ≥1 versus ≥ 2 for remission; and 27% versus 4%, OR 1.70, 95% CI 1.02 to 2.82, P = 0.02 for UCDAI endoscopy sub score greater than or equal to one versus greater than or equal to two for response). With respect to drug class, the lowest placebo response and remission rates were observed in trials evaluating corticosteroids (23%; 95% CI 19 to 29%, and 5%; 95% CI 2 to 11%, respectively). Trials of biologics had the highest placebo response rate (35%; 95% CI 30 to 41%), while trials evaluating aminosalicylates had the highest placebo remission rate (18%; 95% CI 12 to 24%). Disease duration of greater than five years prior to enrolment was associated with a significantly lower placebo response rate compared to disease duration of less than or equal to five years (29% versus 47%, respectively; OR 0.54, 95% CI 0.32 to 0.92, P = 0.02). The requirement of a minimum rectal bleeding score for study eligibility was associated with an increased placebo response rate compared to studies that did not use rectal bleeding for trial eligibility (37% versus 32%, respectively; OR 1.70, 95% CI 1.02 to 2.82, P = 0.02). Finally, the time point of primary outcome assessment was found to be significantly associated with placebo remission rates such that every one week increment in endpoint assessment was associated with a 6% increase in the placebo remission rate (OR 1.06, 95% CI 1.02 to 1.10, P = 0.01).Cumulative meta-analysis indicated a consistent increase in the placebo response rate from 1987 to 2007 (from 13% to 33%), although rates have remained constant from 2008 to 2015 (32% to 34%). Similarly, placebo remission rates increased from 1987 to 2007 (5% to 14%) but have remained constant from 2008 to 2015 (12 to 14%). On meta-regression, there were no statistically significant differences between the 1987-2007 and 2008-2015 point estimates for both response (P = 0.81) and remission (P = 0.32).

AUTHORS' CONCLUSIONS

Placebo response and remission rates vary according to endoscopic disease severity and rectal bleeding score at trial entry, class of agent, disease duration, and the time point at which the primary outcome was measured. These observations have important implications for the design and conduct of future clinical trials in UC and will help researchers design trials, determine required sample sizes and also provide useful information about trial design features which should be considered when planning new trials.

CD103+ Dendritic Cell Function Is Altered in the Colons of Patients with Ulcerative Colitis

BACKGROUND

Human intestinal innate myeloid cells can be divided into 3 subsets: HLA-DRCD14 cells, HLA-DRCD103 dendritic cells (DCs), and HLA-DRCD14CD103 cells. CD103 DCs generate Treg cells and Th17 cells in the ileum, but their function in the colon remains largely unknown. This study characterized CD103 DCs in the colon and investigated whether these cells are implicated in the pathogenesis of ulcerative colitis (UC).

METHODS

Normal intestinal mucosa was obtained from intact sites of patients with colorectal cancer (n = 24). Noninflamed and inflamed colonic tissues were obtained from surgically resected specimens of patients with UC (n = 13). Among LinCD45HLA-DR intestinal lamina propria cells, CD14 cells and CD103 DCs were sorted and analyzed for microRNA expression of cytokines and toll-like receptors by quantitative real-time polymerase chain reaction. In addition, IL-4/IL-5/IL-13/IL-17/IFN-γ production and Foxp3 expression by naive T cells cultured with CD14 cells and CD103 DCs were analyzed.

RESULTS

CD103 DCs in the normal colon showed lower expression of toll-like receptors and proinflammatory cytokines than CD14 cells. Coculture with naive T cells revealed that CD103 DCs generated Treg cells. CD103 DCs from patients with UC did not generate Treg cells, but they induced IFN-γ-, IL-13-, and IL-17-producing CD4 T cells and showed higher expression of IL6 (P < 0.0001), IL23A (P < 0.05), IL12p35 (P < 0.05), and TNF (P < 0.05).

CONCLUSIONS

In patients with UC, CD103 DCs show the impaired ability to generate Treg cells, but exhibit a colitogenic function inducing Th1/Th2/Th17 responses. These findings show how human CD103 DCs could contribute to the pathogenesis of UC.

Emerging treatments for ulcerative colitis: a systematic review

OBJECTIVES

Various investigational medicinal products have been developed for ulcerative colitis (UC). Our aim was to systematically evaluate novel pharmacological therapeutic agents for the treatment of UC.

MATERIAL AND METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations were followed. A search of the medical literature was conducted in the MEDLINE database for original research papers published between 01 January 2010 and 31 October 2014.

RESULTS

Twenty one studies, including 11,524 adults were analyzed. Thirteen different novel therapeutic drug options were identified. Vedolizumab and golimumab were superior to placebo as induction and maintenance therapy. Tofacitinib showed dose related efficacy for induction therapy. Etrolizumab showed higher clinical remission rates compared to placebo. Phosphatidylcholine led to an improved clinical activity index. HMPL-004 may become a mesalamine alternative for mild to moderate UC. PF00547,659 was well tolerated. Statins were not beneficial for acute exacerbations of UC. Abatacept, rituximab and visilizumab did not lead to improved outcomes compared to placebo. Higher concentration of BMS 936557 was associated with improved efficacy compared to placebo. Basiliximab did not enhance corticosteroid efficacy.

CONCLUSIONS

Patients with UC might achieve clinical response or remission by utilizing some of these agents with a favorable side effect profile. Further studies are needed to evaluate their short- and long-term efficacy and safety.

Overcoming disease-specific matrix effect in a clinical pharmacokinetic assay using a microfluidic immunoassay technology

AIM

Etrolizumab, a humanized monoclonal antibody, has demonstrated clinical remission in a Phase II study of ulcerative colitis patients. In the Phase III program, a second indication, Crohn's disease was added. The pharmacokinetic ELISA used in the Phase I/II studies in normal human and ulcerative colitis sera exhibited matrix interference in the Crohn's disease population, necessitating implementation of a new technology. Methodology & results: Optimization of the original ELISA and assay redevelopment using different antibody pairs did not result in substantive improvements, necessitating implementation of an alternative technology for assay development.

CONCLUSION

We highlight the challenges encountered with optimization/redevelopment of the original ELISA and discuss results of the new assay on the Gyros platform.

Frontiers in Drug Research and Development for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is idiopathic, lifelong, immune-mediated diseases, for which curative therapies are not yet available. In the last 15 years, the introduction of monoclonal antibodies targeting tumor necrosis factor-α, a cytokine playing a key role in bowel inflammation, has revolutionized treatment paradigms for IBD. Despite their proven long-term efficacy, however, many patients do not respond or progressively lose response to these drugs. Major advances of knowledge in immunology and pathophysiology of intestinal inflammatory processes have made possible the identification of new molecular targets for drugs, thus opening several new potential therapeutic opportunities for IBD. The abnormal response of intestinal immunity to unknown antigens leads to the activation of T helper lymphocytes and triggers the inflammatory cascade. Sphingosine 1-phosphate receptor agonists negatively modulate the egress of lymphocytes, inducted by antigen-presenting cells, from secondary lymphoid tissues to intestinal wall. Leukocyte adhesion inhibitors (both anti-integrin and anti-Mucosal Vascular Addressin Cell Adhesion Molecule 1) interfere with the tissue homing processes. Activated T helper lymphocytes increase the levels of pro-inflammatory cytokines, such as interleukin 12, 23, and 6, offering several potential pharmacological interventions. The Janus kinases, intracellular enzymes mediating the transduction of several cytokine signals, are other explored targets for treating immune-mediated diseases. Finally, the impact of modulating Smad7 pathway, which is responsible for the down-regulation of the immunosuppressive cytokine transforming growth factor-β signaling, is currently under investigation. The purpose of this review is to discuss the most promising molecules in late-stage clinical development, with a special emphasis on pharmacological properties.

Current and emerging therapeutic targets for IBD

Various therapeutic advances have led to a paradigm shift in the clinical management of patients with IBD. The introduction of immunosuppressive (such as azathioprine) and biologic agents (such as TNF blockers) has markedly reduced the need to use corticosteroids for therapy. Furthermore, the α4β7 integrin blocker vedolizumab has been introduced for clinical IBD therapy. Moreover, various new inhibitors of cytokines (for example, IL-6-IL-6R and IL-12-IL-23 blockers or apremilast), modulators of cytokine signalling events (for example, JAK inhibitors or SMAD7 blocker), inhibitors of transcription factors (for example, GATA3 or RORγt) and new anti-adhesion and anti-T-cell-activation and migration strategies (for example, β7 integrin, sphingosine 1-phosphate receptors and MAdCAM1 inhibitors, regulatory T-cell therapy and stem cells) are currently being evaluated in controlled clinical trials. This Review aims to provide a comprehensive overview about current and future therapeutic approaches for IBD therapy. Furthermore, potential mechanisms of action of these therapeutic approaches and their implications for clinical therapy in IBD are discussed.

αEβ7 Integrin Identifies Subsets of Pro-Inflammatory Colonic CD4+ T Lymphocytes in Ulcerative Colitis

BACKGROUND AND AIMS

The αEβ7 integrin is crucial for retention of T lymphocytes at mucosal surfaces through its interaction with E-cadherin. Pathogenic or protective functions of these cells during human intestinal inflammation, such as ulcerative colitis [UC], have not previously been defined, with understanding largely derived from animal model data. Defining this phenotype in human samples is important for understanding UC pathogenesis and is of translational importance for therapeutic targeting of αEβ7-E-cadherin interactions.

METHODS

αEβ7+ and αEβ7- colonic T cell localization, inflammatory cytokine production and expression of regulatory T cell-associated markers were evaluated in cohorts of control subjects and patients with active UC by immunohistochemistry, flow cytometry and real-time PCR of FACS-purified cell populations.

RESULTS

CD4+αEβ7+ T lymphocytes from both healthy controls and UC patients had lower expression of regulatory T cell-associated genes, including FOXP3, IL-10, CTLA-4 and ICOS in comparison with CD4+αEβ7- T lymphocytes. In UC, CD4+αEβ7+ lymphocytes expressed higher levels of IFNγ and TNFα in comparison with CD4+αEβ7- lymphocytes. Additionally the CD4+αEβ7+ subset was enriched for Th17 cells and the recently described Th17/Th1 subset co-expressing both IL-17A and IFNγ, both of which were found at higher frequencies in UC compared to control.

CONCLUSION

αEβ7 integrin expression on human colonic CD4+ T cells was associated with increased production of pro-inflammatory Th1, Th17 and Th17/Th1 cytokines, with reduced expression of regulatory T cell-associated markers. These data suggest colonic CD4+αEβ7+ T cells are pro-inflammatory and may play a role in UC pathobiology.

The Impact of Therapeutic Antibodies on the Management of Digestive Diseases: History, Current Practice, and Future Directions

The development of therapeutic antibodies represents a revolutionary change in medical therapy for digestive diseases. Beginning with the initial studies that confirmed the pathogenicity of cytokines in inflammatory bowel disease, the development and application of therapeutic antibodies brought challenges and insights into their potential and optimal use. Infliximab was the first biological drug approved for use in Crohn's disease and ulcerative colitis. The lessons learned from infliximab include the importance of immunogenicity and the influence of pharmacokinetics on disease response and outcomes. Building on this foundation, other therapeutic antibodies achieved approval for inflammatory bowel disease and many more are in development for several digestive diseases. In this review, we reflect on the history of therapeutic antibodies and discuss current practice and future directions for the field.

Novel Insights into the Mechanisms of Gut Homing and Antiadhesion Therapies in Inflammatory Bowel Diseases

Therapeutic compounds interfering with T cell trafficking are a new column of inflammatory bowel disease (IBD) treatment. Currently, the anti-α4β7 integrin antibody vedolizumab is successfully used in the clinic and further drugs are likely to follow. Despite these clinical advances, the precise mechanistic background of their action is only gradually elucidated and still a matter of intensive research. Only recently, advances made with the help of new in vivo models and human studies have contributed to shape our concept of T cell trafficking in IBD by deciphering some important and so far unanswered questions. At the same time, basic and clinical data have generated new issues to be addressed on the way toward a clear perception of trafficking mechanisms and toward elucidation of the action of compounds interfering with this process. In this review, we will give a comprehensive outline of all components of T cell trafficking in regard to IBD before discussing the current knowledge concerning targeted interference with integrins in this complex network. Moreover, we will summarize remaining ambiguity and give an outlook on potential future targets.

The Complexity of alpha E beta 7 Blockade in Inflammatory Bowel Diseases

Monoclonal antibodies targeting integrins are emerging as new treatment option in inflammatory bowel diseases. Integrins are molecules involved in cell adhesion and signalling. After the successful introduction of anti-α4β7, currently anti-β7 is under evaluation in a phase three trial. Anti-β7 blocks both α4β7/MAdCAM-1 and αEβ7/E-cadherin interaction, targeting both the homing to and the retention in the gut of potential pathological T cells. Since the physiological and potential pathological roles of immune cells expressing αEβ7 are less distinct than of those expressing α4β7, an overview of the current state of knowledge on αEβ7 in mice and humans in both health and inflammatory bowel diseases is presented here, also addressing the potential consequences of anti-β7 treatment.

Update on the Use of Biologic Therapy in Ulcerative Colitis

OPINION STATEMENT

Ulcerative colitis (UC) is a major form of inflammatory bowel disease and is characterized by chronic inflammation of the colon and rectum and by alternating periods of flares and remissions. Symptoms may include rectal bleeding, abdominal pain, and diarrhea. The pathogenesis of UC is complex and involves a combination of immune dysregulation, genetics, environmental factors, and microbiota. The goal of medical treatment is to induce and maintain remission. Traditionally, the treatment options for UC included 5-aminosalicylates, corticosteroids, and immunomodulators. However, over the past decade, with the approval of various biologic agents for treatment of UC, the management of UC has been revolutionized. Currently, the FDA-approved biologics for treatment of UC include infliximab, adalimumab, golimumab, and vedolizumab. There are a number of other agents which are under investigation and may become available soon as treatment options for UC. The purpose of this article is to provide a summary of various biologics in the treatment of UC.

Novel Targeted Therapies for Inflammatory Bowel Disease

Our growing understanding of the immunopathogenesis of inflammatory bowel disease (IBD) has opened new avenues for developing targeted therapies. These advances in treatment options targeting different mechanisms of action offer new hope for personalized management. In this review we highlight emerging novel and easily administered therapeutics that may be viable candidates for the management of IBD, such as antibodies against interleukin 6 (IL-6) and IL-12/23, small molecules including Janus kinase inhibitors, antisense oligonucleotide against SMAD7 mRNA, and inhibitors of leukocyte trafficking to intestinal sites of inflammation (e.g., sphingosine 1-phosphate receptor modulators). We also provide an update on the current status in clinical development of these new classes of therapeutics.

Etrolizumab for ulcerative colitis: the new kid on the block?

INTRODUCTION

Ulcerative colitis (UC) is a chronic inflammatory bowel disease of unknown etiology. Currently approved therapies include prednisone, TNF antagonists and anti-metabolites which often are ineffective and have frequent adverse effects. Consequently, UC patients are always at risk for developing serious complications that affect their quality of life. Therefore, new treatment options are required.

AREAS COVERED

This article discusses etrolizumab, its mechanism and the potential role it can have in the future of treating UC. Etrolizumab is a humanized monoclonal antibody that selectively blocks lymphocyte trafficking and retention in the gut. The safety and efficacy data was reviewed from all randomized placebo-controlled trials which evaluated etrolizumab for the treatment of UC.

EXPERT OPINION

Etrolizumab is an effective and well-tolerated drug for the treatment of UC. It appears to be a promising molecule that can benefit UC patients.

Differential effects of α4β7 and GPR15 on homing of effector and regulatory T cells from patients with UC to the inflamed gut in vivo

OBJECTIVE

Gut homing of lymphocytes via adhesion molecules has recently emerged as new target for therapy in IBDs. We aimed to analyse the in vivo homing of effector (Teff) and regulatory (Treg) T cells to the inflamed gut via α4β7 and G protein receptor GPR15.

DESIGN

We assessed the expression of homing receptors on T cells in peripheral blood and inflamed mucosa. We studied the migration pattern and homing of Teff and Treg cells to the inflamed gut using intravital confocal microscopy and FACS in a humanised mouse model in dextran sodium sulfate-treated NSG (NOD.Cg-Prkdcscid-Il2rgtm1Wjl/SzJ) mice.

RESULTS

Expression of GPR15 and α4β7 was significantly increased on Treg rather than Teff cells in peripheral blood of patients with UC as compared with Crohn's disease and controls. In vivo analysis in a humanised mouse model showed augmented gut homing of UC Treg cells as compared with controls. Moreover, suppression of UC (but not control) Teff and Treg cell homing was noted upon treatment with the α4β7 antibody vedolizumab. In contrast, siRNA blockade of GPR15 had only effects on homing of Teff cells but did not affect Treg homing in UC. Clinical vedolizumab treatment was associated with marked expansion of UC Treg cells in peripheral blood.

CONCLUSIONS

α4β7 rather than GPR15 is crucial for increased colonic homing of UC Treg cells in vivo, while both receptors control UC Teff cell homing. Vedolizumab treatment impairs homing of UC Treg cells leading to their accumulation in peripheral blood with subsequent suppression of systemic Teff cell expansion.

Integrin antagonists as potential therapeutic options for the treatment of Crohn's disease

INTRODUCTION

Anti-integrin therapy for the treatment of patients with Crohn's disease is rapidly evolving. Two agents, natalizumab and vedolizumab, are approved by the United States Food and Drug Administration for the treatment of Crohn's disease, with vedolizumab the primary anti-integrin used due to a more favorable safety profile. Several other anti-integrins are in various stages of development.

AREAS COVERED

This review discusses the current state of anti-integrin therapy as well as suggestions for positioning of these agents in clinical practice. Emerging anti-integrin therapies, their underlying mechanisms of action, and available safety and clinical data are also reviewed.

EXPERT OPINION

Anti-integrins are effective for the treatment of Crohn's disease, even in patients refractory to other therapies. Their use should be considered in patients with Crohn's disease who do not respond to, develop non-response to, or have contraindications to anti-TNF therapy. Anti-integrin therapies can be offered as a first biologic therapy, in particular for older patients, patients with concurrent multiple sclerosis (natalizumab only), and in patients with contraindications to anti-TNF therapy. In patients with more severe symptoms, providers should consider co-induction with corticosteroids if possible to hasten remission.

Integrins and adhesion molecules as targets to treat inflammatory bowel disease

Inflammatory bowel diseases (IBD) present a typically relapsing-remitting behavior and are characterized by a disabling and progressive course. Anti-tumor necrosis factor (TNF)-α agents have drastically changed the therapeutic management of IBD. However, a significant proportion of patients does not have a primary response, some patients lose response overtime and/or experience side effects. Recently, anti-adhesion molecules were investigated and showed efficacy with a good safety profile. Vedolizumab was recently approved for both Crohn's disease (CD) and ulcerative colitis (UC) and several other molecules are under evaluation in this field. Anti-adhesion molecules could represent a potential therapeutic option for future therapy in IBD. In this review we report the efficacy and safety of major anti-adhesion drugs in active IBD patients.

The Next Wave of Biological Agents for the Treatment of IBD: Evidence from Cochrane Reviews

Multiple new biological treatments for Crohn's disease and ulcerative colitis are becoming available. Specifically, vedolizumab and ustekinumab are monoclonal antibodies that target molecular pathways relevant to disease pathogenesis. What can Cochrane reviews tell us about the efficacy, safety, and immunogenicity of these new agents? A Cochrane inflammatory bowel disease group symposium held at the 2015 Digestive Diseases Week annual meeting addressed these questions. This article reviews the data presented at that session.

The clinical potential of etrolizumab in ulcerative colitis: hypes and hopes

Antiadhesion molecules are effective and safe in patients with ulcerative colitis (UC). Etrolizumab, a monoclonal antibody targeting both α4β7 and αEβ7, represents a promising therapy for patients with UC, since this novel mechanism of action may be effective in blocking leukocyte recruitment both at the vascular and at the mucosal level. Preliminary studies show that etrolizumab is effective in inducing clinical response and remission, and mucosal healing. Moreover, new predictors of response have recently been identified, opening the way to a tailored therapeutic approach. This review of the literature aims to present and discuss the most recent evidence on etrolizumab in UC, focusing on the clinical implications of the use of etrolizumab in UC.

Emerging therapeutic targets and strategies in Crohn's disease

Crohn's disease (CD) is an immune-mediated inflammatory bowel disease, in which inflammation is driven by a complex interaction between the microbiota, immune cells, genes and mediators. New mechanisms of action and several cytokines have been identified as factors involved in the inflammatory process in CD, and many new molecules have been developed to treat this complex disease. New agents have been developed that target leukocyte trafficking, block or adhesion molecules for example, as well as the development of antibodies against classic inflammatory cytokines or therapies directed against IL-12/23 and Janus kinases. The development of selective mechanisms of action and targeting of different cytokines or inflammatory mediators for each patient presents the biggest challenge for the future in CD therapy. Such agents are currently at different phases of development. We aim to review the current literature data on a targeted approach in CD, which could be promising alternative approach for CD patients in the near future.

Systematic Review and Meta-analysis: Placebo Rates in Induction and Maintenance Trials of Ulcerative Colitis

BACKGROUND AND AIMS

Minimisation of the placebo responses in randomised controlled trials [RCTs] is essential for efficient evaluation of new interventions. Placebo rates have been high in ulcerative colitis [UC] clinical trials, and factors influencing this are poorly understood. We quantify placebo response and remission rates in UC RCTs and identify trial design factors influencing them.

METHODS

MEDLINE, EMBASE, and the Cochrane Library were searched from inception through April 2014 for placebo-controlled trials in adult patients with UC of a biological agent, corticosteroid, immunosuppressant, or aminosalicylate. Data were independently doubly extracted. Quality was assessed using the Cochrane risk of bias tool.

RESULTS

In all, 51 trials [48 induction and 10 maintenance phases] were identified. Placebo response and remission rates were pooled according to random-effects models, and mixed-effects meta-regression models were used to evaluate effects of study-level characteristics on these rates. Pooled estimates of placebo remission and response rates for induction trials were 10% (95% confidence interval [CI] 7-13%) and 33% [95% CI 29-37%], respectively. Corresponding values for maintenance trials were 19% [95% CI 11-30%] and 22% [95% CI 17-28%]. Trials enrolling patients with more active disease confirmed by endoscopy [endoscopy subscore ≥ 2] were associated with lower placebo rates. Conversely, placebo rates increased with increasing trial duration and number of study visits.

CONCLUSIONS

Objective assessment of greater disease activity at trial entry by endoscopy lowered placebo rates, whereas increasing trial duration and more interactions with healthcare providers increased placebo rates. These findings have important implications for design and conduct of clinical trials.

Advances in the development of new biologics in inflammatory bowel disease

Biologics have revolutionized the therapeutic approach in inflammatory bowel disease (IBD). Anti-tumor necrosis factor (anti-TNF) agents infliximab and adalimumab currently constitute the major biological therapy in IBD. Additional anti-TNFs such as golimumab and other new biologics are currently being developed for both anti-TNF-naïve and -resistant patients. These include anti-integrins (vedolizumab and etrolizumab), a JAK inhibitor (tofacitinib) and an anti-anti-interleukin (IL)-23 and IL-12 antibody (ustekinumab), among additional drugs in development. The following review discusses the indications, efficacy and safety issues for these novel medications.

Regulatory T-cell depletion in the gut caused by integrin β7 deficiency exacerbates DSS colitis by evoking aberrant innate immunity

Integrin α4β7 controls lymphocyte trafficking into the gut and has essential roles in inflammatory bowel disease (IBD). The α4β7-blocking antibody vedolizumab is approved for IBD treatment; however, high dose of vedolizumab aggravates colitis in a small percentage of patients. Herein, we show that integrin β7 deficiency results in colonic regulatory T (Treg) cell depletion and exacerbates dextran sulfate sodium (DSS) colitis by evoking aberrant innate immunity. In DSS-treated β7-deficient mice, the loss of colonic Treg cells induces excessive macrophage infiltration in the colon via upregulation of colonic epithelial intercellular adhesion molecule 1 and increases proinflammatory cytokine expression, thereby exacerbating DSS-induced colitis. Moreover, reconstitution of the colonic Treg cell population in β7-deficient mice suppresses aberrant innate immune response in the colon and attenuates DSS colitis. Thus, integrin α4β7 is essential for suppression of DSS colitis as it regulates the colonic Treg cell population and innate immunity.

Integrin-based therapeutics: biological basis, clinical use and new drugs

Integrins are activatable molecules that are involved in adhesion and signalling. Of the 24 known human integrins, 3 are currently targeted therapeutically by monoclonal antibodies, peptides or small molecules: drugs targeting the platelet αIIbβ3 integrin are used to prevent thrombotic complications after percutaneous coronary interventions, and compounds targeting the lymphocyte α4β1 and α4β7 integrins have indications in multiple sclerosis and inflammatory bowel disease. New antibodies and small molecules targeting β7 integrins (α4β7 and αEβ7 integrins) and their ligands are in clinical development for the treatment of inflammatory bowel diseases. Integrin-based therapeutics have shown clinically significant benefits in many patients, leading to continued medical interest in the further development of novel integrin inhibitors. Of note, almost all integrin antagonists in use or in late-stage clinical trials target either the ligand-binding site or the ligand itself.

Assessment of Disease-Related Therapeutic Protein Drug-Drug Interaction for Etrolizumab in Patients With Moderately to Severely Active Ulcerative Colitis

The efficacy and safety of etrolizumab, a humanized IgG1 mAb, were evaluated in patients with ulcerative colitis (UC) in a phase 2 study (EUCALYPTUS). The current study assessed the risk of therapeutic protein drug-drug interaction (TP-DDI) of etrolizumab on CYP3A activity in patients with UC. Literature review was performed to compare serum proinflammatory cytokine levels and pharmacokinetic (PK) parameters of CYP3A substrate drugs between patients with inflammatory bowel disease (IBD) and healthy subjects. Treatment effect of etrolizumab on CYP3A activity was evaluated by measuring colonic CYP3A4 mRNA expression and serum C-reactive protein (CRP) in EUCALYPTUS patients. Literature data suggested similar levels between IBD patients and healthy subjects for serum proinflammatory cytokines and PK parameters of CYP3A substrate drugs. Additionally, treatment with etrolizumab did not change colonic CYP3A4 mRNA expression or serum CRP levels in UC patients. In conclusion, our results indicate a low TP-DDI risk for etrolizumab in UC patients, particularly on medications metabolized by CYP3A.

Evaluation of assay interference and interpretation of CXCR4 receptor occupancy results in a preclinical study with MEDI3185, a fully human antibody to CXCR4

Background

Receptor occupancy (RO) assays provide a means to measure the direct interaction of therapeutics with their cell surface targets. Free receptor assays quantify cell‐surface receptors not bound by a therapeutic while total receptor assays quantify the amount of target on the cell surface.

Methods

We developed both a flow cytometry‐based free RO assay to detect free surface CXCR4, and a total surface CXCR4 assay. In an effort to evaluate potential displacement interference, we performed in vitro experiments to compare on‐cell affinity with the IC₅₀ values from in vitro and in vivo from the free CXCR4 assay. We determined free and total surface CXCR4 on circulating blood cells in cynomolgus monkeys dosed with MEDI3185, a fully human monoclonal antibody to CXCR4.

Results

We devised an approach to evaluate displacement interference during assay development and showed that our free assay demonstrated little to no displacement interference. After dosing cynomolgus monkeys with MEDI3185, we observed dose‐dependence in the magnitude and duration of receptor occupancy and found CXCR4 to increase on lymphocytes, monocytes, and granulocytes. In a multiple dose study, we observed time points where surface CXCR4 appeared fully occupied but MEDI3185 was not detectable in serum. These paradoxical results represented a type of assay interference, and by comparing pharmacokinetic, ADA and total CXCR4 results, the most likely reason for the free CXCR4 results was the emergence of neutralizing anti‐drug antibodies (ADA). The total CXCR4 assay was unaffected by ADA and provided a reliable marker of target modulation in both in vivo studies. © 2015 The Authors Cytometry Part B: Clinical Cytometry Published byWiley Periodicals, Inc.

Etrolizumab for induction of remission in ulcerative colitis

BACKGROUND

Etrolizumab (rhuMAb beta7) is an anti-integrin that selectively targets the β7 subunits of the α4β7 and αEβ7 integrins, which are involved in the pathogenesis of ulcerative colitis.

OBJECTIVES

The objectives of this review were to assess the efficacy and safety of etrolizumab for induction of remission in ulcerative colitis.

SEARCH METHODS

We searched PubMed, MEDLINE, EMBASE, and the Cochrane Library (CENTRAL) from inception to 12 March 2015. References and conference abstracts were searched to identify additional studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) trials in which etrolizumab was compared to placebo or another active comparator in patients with active ulcerative colitis were included.

DATA COLLECTION AND ANALYSIS

Two authors independently screened studies for inclusion, assessed methodological quality and extracted data. We assessed methodological quality using the Cochrane risk of bias tool. The primary outcome was failure to induce clinical remission (as defined by the primary studies). Secondary outcomes included failure to induce clinical improvement (as defined by the primary studies), failure to induce endoscopic remission (as defined by the primary studies), adverse events, serious adverse events, withdrawal due to adverse events, and health-related quality of life (as defined by the primary studies). We assessed the overall quality of the evidence using the GRADE criteria. We calculated the risk ratio (RR) and corresponding 95% confidence interval (CI) for each dichotomous outcome.

MAIN RESULTS

Two RCTs including 172 patients with moderate to severe UC who failed conventional therapy met the inclusion criteria. Both studies were rated as low risk of bias. We did not pool efficacy data from the two included studies due to differences in dose and route of administration. The small phase I study found no statistically significant differences between etrolizumab and placebo in the proportion of patients who failed to enter remission (RR 1.04, 95% CI 1.04 to 1.69; participants = 23) or respond at week 10 (RR 1.67, 95% CI 0.26 to 10.82; participants = 23). The phase II study reported on failure to enter clinical remission at weeks 6 and 10. In the etrolizumab group 91% (71/78) of patients failed to enter remission at week 6 compared to 95% (39/41) of placebo patients (RR 0.96, 95% CI 0.87 to 1.06). Subgroup analysis revealed no statistically significant differences by dose. At week 10, there was a statistically significant difference in clinical remission rates favouring etrolizumab over placebo. Of the patients who received etrolizumab, 85% (66/78) failed to enter remission at week 10 compared to 100% (41/41) patients in the placebo group (RR 0.86, 95% CI 0.77 to 0.95). A subgroup analysis by dose found a statistically significant difference in clinical remission rates favoring 100 mg etrolizumab over placebo (RR 0.81 CI 95% 0.68 to 0.96), but not 300 mg etrolizumab over placebo (RR 0.91, 95% CI 0.80 to 1.03). No significant heterogeneity was detected for this comparison (P = 0.28, I(2) = 13.5%). GRADE analyses indicated that the overall quality of evidence for the clinical remission outcomes was moderate due to sparse data. Both of the included studies reported on safety. The outcome adverse events was initially pooled, however this analysis was removed due to high heterogeneity (I(2) = 88%). The phase I study found no statistically significant difference between etrolizumab and placebo in the proportion of patients who had at least one adverse event. Ninety-five per cent (36/38) of etrolizumab patients had at least one adverse event compared to 100% (10/10) of placebo patients (RR 0.98, 95% CI 0.84 to 1.14). Common adverse events reported in the phase I study included exacerbation of UC, headache, fatigue, abdominal pain, dizziness, nasopharyngitis, nausea, arthralgia and urinary tract infection. There was a statistically significant difference between etrolizumab and placebo in the proportion of patients who had at least one adverse event. Fifty-six per cent (44/78) of etrolizumab patients had at least one adverse event compared to 79% of placebo patients (RR 0.71, 95% CI 0.55 to 0.91). A GRADE analysis indicates that the overall quality of the evidence for this outcome was moderate due to sparse data. Common adverse events reported in the phase II study included worsening UC, nasopharyngitis, nervous system disorders, headache and arthralgia . A pooled analysis of two studies indicates that there was no statistically significant difference in the proportion of patients who had a serious adverse event. Twelve per cent (14/116) of etrolizumab patients had a serious adverse event compared to 12% of placebo patients (6/49) (RR 0.92, 95% CI 0.36 to 2.34). A GRADE analysis indicated that the overall quality of the evidence for this outcome was low due to very sparse data (20 events). Common serious adverse events included worsening of UC, impaired wound healing and bacterial peritonitis.

AUTHORS' CONCLUSIONS

Moderate quality evidence suggests that etrolizumab may be an effective induction therapy for some patients with moderate to severe ulcerative colitis who have failed conventional therapy. Due to small numbers of patients in dose subgroups the optimal dosage of etrolizumab is unclear. Due to sparse data we are uncertain regarding the risk of adverse events and serious adverse events. Further studies are needed to determine the efficacy and safety of etrolizumab in this patient population. There are five ongoing phase III etrolizumab trials and two ongoing open-label extension studies that will provide important new information on the efficacy, safety and optimal dose of this drug for the treatment of UC.

Hepatic manifestations of non-steroidal inflammatory bowel disease therapy

Inflammatory bowel disease (IBD) is composed of Crohn's disease and ulcerative colitis and is manifested by both bowel-related and extraintestinal manifestations. Recently the number of therapeutic options available to treat IBD has dramatically increased, with each new medication having its own mechanism of action and side effect profile. A complete understanding of the hepatotoxicity of these medications is important in order to distinguish these complications from the hepatic manifestations of IBD. This review seeks to evaluate the hepatobiliary complications of non-steroid based IBD medications and aide providers in the recognition and management of these side-effects.

Promising biological therapies for ulcerative colitis: A review of the literature

Ulcerative colitis (UC) is a chronic lifelong condition characterized by alternating flare-ups and remission. There is no single known unifying cause, and the pathogenesis is multifactorial, with genetics, environmental factors, microbiota, and the immune system all playing roles. Current treatment modalities for UC include 5-aminosalicylates, corticosteroids, immunosuppressants (including purine antimetabolites, cyclosporine, and tacrolimus), and surgery. Therapeutic goals for UC are evolving. Medical treatment aims to induce remission and prevent relapse of disease activity. Infliximab, an anti-tumor necrosis factor (TNF)-α monoclonal antibody, is the first biological agent for the treatment of UC. Over the last decade, infliximab and adalimumab (anti-TNF-α agents) have been used for moderate to severe UC, and have been shown to be effective in inducing and maintaining remission. Recent studies have indicated that golimumab (another anti-TNF-α agent), tofacitinib (a Janus kinase inhibitor), and vedolizumab and etrolizumab (integrin antagonists), achieved good clinical remission and response rates in UC. Recently, golimumab and vedolizumab have been approved for UC by the United States Food and Drug Administration. Vedolizumab may be used as a first-line alternative to anti-TNF-α therapy in patients with an inadequate response to corticosteroids and/or immunosuppressants. Here, we provide updated information on various biological agents in the treatment of UC.

[Targeting and role of α4β7 integrin in the pathophysiology of IBD and HIV infection]

Integrins are a large family of heterodimeric cell adhesion molecules that are key regulators in multiple biological functions. They orchestrate cell-cell and cell-extracellular matrix (ECM) adhesive interactions from embryonic development to mature tissue function, and are thus involved in cell migration, proliferation, differentiation, and survival. As such, they are also involved in human diseases, such as thrombotic diseases, inflammation, cancer, fibrosis and infectious diseases. Integrins are exciting pharmacological targets because they are exposed on the cell surface. Indeed, several compounds have been developed that block integrins function, and five have been approved as therapeutic drugs for use in clinic. This review will detail the role of α4β7, an integrin of particular relevance for mucosal diseases such as IBD (inflammatory bowel disease) and also, as reported more recently, HIV infection.

Multiplexing of receptor occupancy measurements for pharmacodynamic biomarker assessment of biopharmaceuticals

Background

Receptor occupancy (RO) assays measure drug target engagement, and are used as pharmacodynamic (PD) biomarkers. RO assays are commonly performed by flow cytometry and often require multiplexing for assessment of multiple PD biomarkers when specimen volumes are limited. We present multiplexed RO assays for an IGF1R‐EGFR bispecific antibody (Bs‐Ab) and a CTLA4‐Ig recombinant fusion protein to demonstrate key considerations for accurate RO assessment.

Methods

RO in cynomolgus monkeys was determined in whole blood using flow cytometry. Free and total receptors were measured using anti‐receptor fluorescence‐labeled detection reagents, competitive and noncompetitive to drug, respectively.

Results

RO of IGF1R was examined as PD for Bs‐Ab, since IGF1R was expressed on blood cells. Multiplexed measurements of free and total IGF1R showed that IGF1R expression measured by total receptor was highly variable, impacting interpretation of free‐IGF1R. Normalization of free‐over‐total IGF1R measurements compensated for variability of receptor expression allowing for accurate RO assessment. RO of CTLA4‐Ig, a recombinant fusion protein targeting CD80 and CD86 receptors, was multiplexed to simultaneously measure target engagements for both receptors. Both RO methods demonstrated specificity of receptor measurements without cross‐reactivity to each other in multiplexed formats. RO methods were used for evaluation of PD activity of Bs‐Ab and CTLA4‐Ig in cynomolgus monkeys. In both cases, RO results showed dose‐dependent target engagement, corresponding well to the pharmacokinetics.

Conclusions

Multiplexed RO methods allowed accurate assessment of PD activity for Bs‐Ab and CTLA4‐Ig, facilitating development of these biopharmaceuticals from preclinical to clinical stages. © 2015 The Authors Cytometry Part B: Clinical Cytometry Published by Wiley Periodicals, Inc.

Medical Therapy of Active Ulcerative Colitis

Background

Medical therapy of mild and moderate ulcerative colitis (UC) of any extent is evidence-based and standardized by national and international guidelines. However, patients with steroid-refractory UC still represent a challenge.

Methods

A literature search using PubMed (search terms: ulcerative colitis, therapy, new, 1-2008-2015) resulted in 821 publications. For the current article, 88 citations were extracted including 36 randomized controlled studies, 18 reviews, and 8 meta-analyses.

Results

In steroid-refractory UC, early intensive therapy using anti-tumor necrosis factor (TNF) antibodies or the calcineurin inhibitors cyclosporine and tacrolimus is indicated in any case to prevent progression to a toxic megacolon and/or to avoid proctocolectomy. In patients with chronic disease activity, treatment with anti-TNF antibodies has a higher level of evidence than azathioprine therapy and should therefore be preferred. However, there is a subgroup of UC patients who may achieve prolonged steroid-free remission on azathioprine monotherapy. The importance of vedolizumab, a newly registered inhibiting antibody against integrin, has not yet been fully clarified since direct comparison studies are lacking, in particular in relation to anti-TNF antibodies.

Conclusion

There is a great need for additional innovative therapies, especially in cases of primary non-response or secondary loss of response to anti-TNF antibodies. New small molecules (Janus kinase inhibitors) are promising with an acceptable safety profile and efficacy in UC. Further, strategies that target the intestinal microbiome are currently considered for patients with active or relapsing UC, and may in the future open up new therapeutic options.

Inflammatory Bowel Disease: An Overview of Immune Mechanisms and Biological Treatments

Inflammatory bowel diseases (IBD) are characterized by chronic inflammation of the intestinal tract associated with an imbalance of the intestinal microbiota. Crohn's disease (CD) and ulcerative colitis (UC) are the most widely known types of IBD and have been the focus of attention due to their increasing incidence. Recent studies have pointed out genes associated with IBD susceptibility that, together with environment factors, may contribute to the outcome of the disease. In ulcerative colitis, there are several therapies available, depending on the stage of the disease. Aminosalicylates, corticosteroids, and cyclosporine are used to treat mild, moderate, and severe disease, respectively. In Crohn's disease, drug choices are dependent on both location and behavior of the disease. Nowadays, advances in treatments for IBD have included biological therapies, based mainly on monoclonal antibodies or fusion proteins, such as anti-TNF drugs. Notwithstanding the high cost involved, these biological therapies show a high index of remission, enabling a significant reduction in cases of surgery and hospitalization. Furthermore, migration inhibitors and new cytokine blockers are also a promising alternative for treating patients with IBD. In this review, an analysis of literature data on biological treatments for IBD is approached, with the main focus on therapies based on emerging recombinant biomolecules.

Receptor occupancy assessment by flow cytometry as a pharmacodynamic biomarker in biopharmaceutical development

Receptor occupancy (RO) assays are designed to quantify the binding of therapeutics to their targets on the cell surface and are frequently used to generate pharmacodynamic (PD) biomarker data in nonclinical and clinical studies of biopharmaceuticals. When combined with the pharmacokinetic (PK) profile, RO data can establish PKPD relationships, which are crucial for informing dose decisions. RO is commonly measured by flow cytometry on fresh blood specimens and is subject to numerous technical and logistical challenges. To ensure that reliable and high quality results are generated from RO assays, careful assay design, key reagent characterization, data normalization/reporting, and thorough planning for implementation are of critical importance during development. In this article, the authors share their experiences and perspectives in these areas and discuss challenges and potential solutions when developing and implementing a flow cytometry‐based RO method in support of biopharmaceutical drug development. © 2015 The Authors Cytometry Part B: Clinical Cytometry Published by Wiley Periodicals, Inc.

Efficacy and Safety of Natalizumab and Vedolizumab for the Management of Crohn's Disease: A Systematic Review and Meta-analysis

BACKGROUND

We assessed the risk-benefit profile of anti-α4-integrins, natalizumab (NAT), and vedolizumab (VEDO), in Crohn's disease through a systematic review and meta-analysis of randomized controlled trials.

METHODS

We searched multiple electronic databases through July 2014 and identified 8 randomized controlled trials in adults with Crohn's disease comparing NAT (5 trials) or VEDO (3 trials) with placebo. Efficacy outcomes were induction of remission, response, and improvement in quality of life; safety outcomes were serious adverse events, infusion reactions, infections, and treatment discontinuation. We performed subgroup analysis based on anti-tumor necrosis factor (TNF)-α exposure and estimated summary relative risk (RR) or mean difference, with 95% confidence intervals (CIs).

RESULTS

Anti-α4-integrins were superior to placebo for induction of remission (RR, 0.87; 95% CI, 0.84-0.91), with similar estimates for NAT (RR, 0.86; 95% CI, 0.80-0.93) and VEDO (RR, 0.87; 95% CI, 0.79-0.95). Both NAT and VEDO were equally efficacious for anti-TNF-naive (NAT: RR, 0.87; 95% CI, 0.75-1.00; VEDO: RR, 0.86; 95% CI, 0.79-0.94) and anti-TNF-exposed patients (NAT: RR, 0.86; 95% CI, 0.76-0.99; VEDO: RR, 0.89; 95% CI, 0.78-1.01). Anti-α4-integrins were effective in inducing clinical response and improving quality of life, with no significant difference between NAT and VEDO. Rates of serious adverse events, infusion reactions, infections, and treatment discontinuation were similar for NAT and VEDO. No cases of progressive multifocal leukoencephalopathy have been observed with VEDO to date.

CONCLUSIONS

NAT and VEDO are effective in inducing remission and response in patients with Crohn's disease, with similar efficacy in anti-TNF-naive and anti-TNF-exposed patients.

Systematic review and meta-analysis: opportunistic infections and malignancies during treatment with anti-integrin antibodies in inflammatory bowel disease

BACKGROUND

Anti-integrin antibodies are effective therapies for Crohn's disease (CD) and ulcerative colitis (UC). However, these drugs carry theoretical risks of opportunistic infection and malignancy.

AIM

To pool data from all placebo-controlled studies, to estimate risk of opportunistic infection or malignancy with anti-integrin antibodies.

METHODS

MEDLINE, EMBASE and the Cochrane central register of controlled trials were searched (up to December 2014). Randomised placebo-controlled trials of anti-integrin antibodies in adults with active or quiescent CD or UC were eligible. Dichotomous data were pooled to obtain a relative risk (RR) of opportunistic infection or malignancy, with 95% confidence intervals (CIs).

RESULTS

The search strategy identified 1579 citations, 12 of which were eligible (four trials of natalizumab, six of vedolizumab and two of etrolizumab). The RR of developing an opportunistic infection was not significantly higher with non-gut specific (2.34; 95% CI 0.05-108.72) or gut specific anti-integrin antibodies (1.55; 95% CI 0.16-14.83). The RR was generally higher in trials of non-gut specific anti-integrin antibodies with duration of therapy ≥52 weeks (RR = 15.00; 95% CI 0.86-261), but remained non-significant. The RR of malignancy was not elevated with non-gut specific (1.57; 95% CI 0.19-12.74) or gut specific anti-integrin antibodies (0.78; 95% CI 0.15-4.02).

CONCLUSIONS

Absolute numbers of opportunistic infections were higher with anti-integrin antibodies, but this difference is not statistically significant. There was no increased risk of malignancy detected. Long-term data in large prospective cohorts are needed to further assess this issue.

The unusual suspects--innate lymphoid cells as novel therapeutic targets in IBD

Innate lymphoid cells (ILCs) are a family of immune cells that selectively accumulate in mucosal tissues serving as sentinels at the vanguard of host protective immunity. However, they are also implicated as cellular mediators of immune-mediated diseases, most notably IBD. ILCs are subdivided into distinct lineages based on the expression of effector cytokines and master transcription factors that programme their differentiation and inflammatory behaviour. Strikingly, these subsets closely resemble CD4(+) T-cell lineages, including T helper (TH)1, TH2 and TH17 cells that are similarly implicated in immune-mediated diseases. However, ILCs that promote the maintenance of intestinal epithelial cells, mostly through production of IL-22, also exist. ILCs rapidly respond to environmental cues, including cytokines, metabolic signals and luminal bacteria. They are potent and immediate producers of key cytokines linked to IBD pathogenesis, including TNF, IL-17, IL-22 and IFN-γ. Some subsets are implicated as mediators of chronic intestinal inflammation, whereas others might provide protective functions. They are present in the gut of patients with IBD and, intriguingly, closer scrutiny of IBD susceptibility loci shows that many of these genes are either expressed by, or are intimately linked to, ILC function. Looking forward, targeting ILCs could represent a new IBD treatment paradigm.

Efficacy and safety of antiintegrin antibody for inflammatory bowel disease: a systematic review and meta-analysis

We sought to evaluate the safety and efficacy of available biologics that inhibit T-cell migration by blocking α4β7 integrins in inflammatory bowel diseases. The aim of this study is to evaluate whether Crohn disease (CD) patients receiving either vedolizumab or natalizumab have any different effect in CD Activity Index (CDAI). Using Medline, Excerpta Medica dataBASE, Cochrane Central Register of Controlled Trials (CENTRAL), and Google Scholar until October 31, 2013, we identified 10 studies examining the safety and efficacy of specific integrin inhibitors—vedolizumab, which targets an epitope comprising the α4β7 heterodimer; natalizumab, which recognizes the α4 integrin subunit; etrolizumab, which is specific for the β7 subunit—in the treatment of CD and ulcerative colitis (UC). CD patients receiving either vedolizumab or natalizumab demonstrated a modest increase in remission rate, when compared with that of the placebo group. Further, although both treatments reduced the CDAI slightly, the observed clinical response was less robust than that of the remission rate. UC patients treated with vedolizumab and natalizumab were found to show more prominent increases in both remission and clinical response, compared with placebo, than patients with CD. Etrolizumab, however, was not found to significantly affect either response or remission rates in UC patients. Biologics targeting integrins show promise as therapeutics in the treatment of inflammatory bowel disease in patients who are either nonresponsive or intolerant to traditional approaches, though further research is necessary to optimize treatment efficacies.

New targeted therapies such as anti-adhesion molecules, anti-IL-12/23 and anti-Janus kinases are looking toward a more effective treatment of inflammatory bowel disease

Antitumor necrosis factor α agents have dramatically changed the management of inflammatory bowel disease (IBD). However, a significant proportion of patients does not respond or lose response over time. Hence, there is an urgent need for new molecules, with different mechanisms of action, and with a targeted and more effective approach. These new drugs include either small molecules or biological agents. We describe the three most promising classes of molecules in the field of IBD: anti-adhesion, anti-interleukin 12/23 and anti-Janus Kinases therapies.

Development of drugs to target interactions between leukocytes and endothelial cells and treatment algorithms for inflammatory bowel diseases

Increased understanding of the pathogenesis of inflammatory bowel diseases (IBDs) has led to new therapeutic strategies. One of these is to target the molecules that regulate interactions between leukocytes and endothelial cells at sites of inflammation (mainly leukocyte integrins and endothelial cell adhesion molecules of the immunoglobulin superfamily). These molecules have been validated as therapeutic targets for IBD; several have shown efficacy, and 2 have been approved by the Food and Drug Administration for treatment of IBD. Natalizumab, the first anti-integrin antibody tested for treatment of IBD, blocks the α4 subunit. Although it is effective, its clinical use has been limited by its association with risk of progressive multifocal leukoencephalopathy. Other, allegedly more selective drugs that affect leukocyte recruitment in the gastrointestinal tract have been developed or are under investigation and could increase safety. These include vedolizumab and AMG 181 (antibodies against α4β7), etrolizumab (anti-β7), and PF-00547659 (anti-mucosal vascular addressin cell adhesion molecule 1). Other agents have been developed to block α4 (the small molecule AJM300), CCR9 (the small molecule CCX282-B), and CXCL10 (the antibody eldelumab). We review the scientific rationale for inhibiting interactions between leukocytes and endothelial cells to reduce intestinal inflammation and analyze the clinical studies that have been performed to test these new molecules, with particular attention to safety. We propose an evidence-based clinical positioning of this class of drugs.

Targeting integrins and adhesion molecules to combat inflammatory bowel disease

: The etiologies of Crohn's disease and ulcerative colitis, the 2 major forms of inflammatory bowel disease in humans, remain unknown, but experimental studies suggest that inflammatory bowel disease results from interaction between environmental and genetic factors, which promotes an exaggerated and inappropriately controlled inflammatory response that is directed against normal components of the gut flora. There is also evidence that tissue damage is due to a dynamic interplay between immune and nonimmune cells, and recruitment of lymphocytes from the blood stream to the gut wall is crucial for amplifying and sustaining the ongoing mucosal inflammation. These advances have led to the development of several compounds blocking gut homing of effector lymphocytes, which have recently been used or are now ready to move into clinical practice. This article summarizes the recent data on the use of integrin-targeting and adhesion molecule-targeting therapeutics to attenuate the detrimental inflammatory response in inflammatory bowel disease.

Pharmacology of AMG 181, a human anti-α4 β7 antibody that specifically alters trafficking of gut-homing T cells

BACKGROUND AND PURPOSE

AMG 181 is a human anti-α4 β7 antibody currently in phase 1 and 2 trials in subjects with inflammatory bowel diseases. AMG 181 specifically targets the α4 β7 integrin heterodimer, blocking its interaction with mucosal addressin cell adhesion molecule-1 (MAdCAM-1), the principal ligand that mediates α4 β7 T cell gut-homing.

EXPERIMENTAL APPROACH

We studied the in vitro pharmacology of AMG 181, and the pharmacokinetics and pharmacodynamics of AMG 181 after single or weekly i.v. or s.c. administration in cynomolgus monkeys for up to 13 weeks.

KEY RESULTS

AMG 181 bound to α4 β7 , but not α4 β1 or αE β7 , and potently inhibited α4 β7 binding to MAdCAM-1 (but not vascular cell adhesion molecule-1) and thus inhibited T cell adhesion. Following single i.v. administration, AMG 181 Cmax was dose proportional from 0.01 to 80 mg·kg(-1) , while AUC increased more than dose proportionally. Following s.c. administration, dose-proportional exposure was observed with single dose ranging from 5 to 80 mg·kg(-1) and after 13 weekly doses at levels between 20 and 80 mg·kg(-1) . AMG 181 accumulated two- to threefold after 13 weekly 80 mg·kg(-1) i.v. or s.c. doses. AMG 181 had an s.c. bioavailability of 80%. The linear elimination half-life was 12 days, with a volume of distribution close to the intravascular plasma space. The mean trend for the magnitude and duration of AMG 181 exposure, immunogenicity, α4 β7 receptor occupancy and elevation in gut-homing CD4+ central memory T cell count displayed apparent correlations.

CONCLUSIONS AND IMPLICATIONS

AMG 181 has in vitro pharmacology, and pharmacokinetic/pharmacodynamic and safety characteristics in cynomolgus monkeys that are suitable for further investigation in humans.

Lymphocyte homing antagonists in the treatment of inflammatory bowel diseases

Lymphocyte homing antagonists represent promising therapeutic agents for the treatment of idiopathic inflammatory bowel disease (IBD). Several critical molecules involved in the recruitment of inflammatory cells in the intestine, including integrins and chemokine receptors, have been successfully targeted for the treatment of IBD. These agents have shown great promise for the induction and maintenance of remission for both Crohn disease and ulcerative colitis. This article discusses currently approved prototypic agents for the treatment of IBD (natalizumab, anti-α4 integrin; vedolizumab, anti-α4β7 integrin), and several other agents in the same class currently under development.

[Treatment of severe ulcerative colitis flares]

The treatment of severe ulcerative colitis remains a challenge for gastroenterologists. A not inconsiderable number of patients will experience severe flares throughout their lives and will require hospitalization. Mortality in severe ulcerative colitis is still high and consequently treatment must be aggressive, avoiding delays in rescue therapies or even surgery. The aim of this review was to describe the medical treatment of severe ulcerative colitis, highlighting recent therapeutic advances.