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

Advances in IBD genetics

IBD is a spectrum of chronic disorders that constitute an important health problem worldwide. The hunt for genetic determinants of disease onset and course has culminated in the Immunochip project, which has identified >160 loci containing IBD susceptibility genes. In this Review, we highlight how genetic association studies have informed our understanding of the pathogenesis of IBD by focusing research efforts on key pathways involved in innate immunity, autophagy, lymphocyte differentiation and chemotaxis. Several of these novel genetic markers and cellular pathways are promising candidates for patient stratification and therapeutic targeting.

Vedolizumab for the treatment of ulcerative colitis

Ulcerative colitis is a chronic inflammatory disease of the large intestine that often develops in the young. A few new treatment options have become available in the past decade, but management of a large proportion of patients still remains challenging because of side effects, unresponsiveness and cost. A novel strategy targeting trafficking of immune cells to the sites of inflammation involves reducing expression or binding of adhesion molecules to integrins. Natalizumab was the first therapeutic antibody blocking infiltration of leukocytes, but because of lack of selectivity to the gut and associated risk of progressive multifocal leukoencephalopathy, it will probably never be tested in ulcerative colitis. In this article we discuss molecules that block leukocyte trafficking to inflamed bowel that have been tested in ulcerative colitis. Because of favourable efficacy and safety data, we will review the development, pharmacology and clinical data of vedolizumab, a gut-selective α4β7 antibody, in depth.

Integrin modulators: a patent review

INTRODUCTION

Integrins are heterodimeric cell surface receptors, which enable adhesion, proliferation, and migration of cells by recognizing binding motifs in extracellular matrix (ECM) proteins. As transmembrane linkers between the cytoskeleton and the ECM, they are able to recruit a huge variety of proteins and to influence signaling pathways bidirectionally, thereby regulating gene expression and cell survival. Hence, integrins play a key role in various physiological as well as pathological processes, which has turned them into an attractive target for pharmaceutical research.

AREAS COVERED

In this review, the latest therapeutic developments of drug candidates and recently patented integrin ligands are summarized.

EXPERT OPINION

Integrins have been proven to be valuable therapeutic targets in the treatment of several inflammatory and autoimmune diseases, where leukocyte adhesion processes are regulated by them. Furthermore, they play an important role in pathological angiogenesis and tumor metastasis, being a promising target for cancer therapy.

New strategies for treatment of inflammatory bowel disease

The etiology of inflammatory bowel disease (IBD), of which ulcerative colitis (UC) and Crohn’s disease (CD) are the two most prevailing entities, is unknown. However, IBD is characterized by an imbalanced synthesis of pro-inflammatory mediators of the inflamed intestine, and for more than a decade tumor necrosis factor-(TNF) α has been a major target for monoclonal antibody therapy. However, TNF inhibitors are not useful for one third of all patients (i.e. “primary failures”), and further one third lose effect over time (“secondary failures”). Therefore, other strategies have in later years been developed including monoclonal antibodies targeting the interleukin (IL)-6 family of receptors (the p40 subunit of IL-12/IL-23) as well as monoclonal antibodies inhibiting adhesion molecules (the α₄β₇ heterodimers), which direct leukocytes to the intestinal mucosa. Recently, small molecules, which are inhibitors of Janus kinases (JAKs), hold promise with a tolerable safety profile and efficacy in UC, and the field of nanomedicine is emerging with siRNAs loaded into polyactide nanoparticles that may silence gene transcripts at sites of intestinal inflammation. Thus, drug development for IBD holds great promise, and patients as well as their treating physicians can be hopeful for the future.

Review article: anti-adhesion therapies for inflammatory bowel disease

BACKGROUND

A high proportion of patients with inflammatory bowel disease (IBD) do not achieve clinical remission with the current therapies including mesalazine (mesalamine), immunossupresants (IMS) and antibodies against tumour necrosis factor (anti-TNF). Moreover, IMS and anti-TNF involve a nonnegligible risk for infections and/or malignancies. The anti-adhesion molecules are one of the most interesting new treatments because of their gut-selectivity.

AIM

To review the physiopathology of the adhesion molecules and the current drugs targeting this mechanism.

METHODS

We performed a literature review in PubMed and in clinicaltrials.gov using the terms 'anti-adhesion molecules', 'inflammatory bowel disease', 'natalizumab', 'vedolizumab', 'AMG181', 'Etrolizumab', 'PF-00547659', 'AJM300', 'Alicaforsen' and 'CCX282-B' up to November 2013.

RESULTS

A total of eight drugs were found including those targeting the α4β1, α4β7 or αEβ7 integrins as well as the ICAM-1 and MAdCAM-1 addressins and the chemokine receptor 9. The rationale for these drugs is the blockade of gut-homing T lymphocytes and the ones targeting the α4β7/MAdCAM-1 interaction presented the most promising results in luminal disease. Vedolizumab, an α4β7 antibody, has completed phase 3 trials with very positive results especially for ulcerative colitis. However, many questions remain unanswered such as the effect of these therapies in perianal disease and extraintestinal manifestations.

CONCLUSIONS

The blockade of the α4β7/MAdCAM-1 interaction and especially vedolizumab is an effective and safe gut-specific treatment for IBD. Further studies are needed to clarify the efficacy and safety of the other anti-adhesion drugs and to define the specific indications of these therapies in the different scenarios of IBD.

Novel concepts in inflammatory bowel disease

INTRODUCTION

Clinical management in inflammatory bowel disease (IBD) is constantly changing. Although improvement in symptoms is of paramount importance, using this as the only surrogate marker of disease activity might underestimate disease burden.

SOURCES OF DATA

New data from randomized clinical trials are now available. Treatment paradigms are constantly changing leading to an evolution in the therapeutic approach in routine IBD practice.

AREAS OF AGREEMENT

Patients with an aggressive disease phenotype should be identified at the onset and treated more intensely in order to achieve long-lasting mucosal remission.

AREAS OF CONTROVERSY

Patients who have mild and indolent disease need to be identified and not over treated.

GROWING POINTS

The primary endpoint in IBD management should ideally be mucosal healing. Ample data are now available that correlates mucosal healing with surgical-free outcomes with minimal intestinal damage and patient disability. However, the exact degree of mucosal healing that will lead to improved long-term remission, decreased hospital and surgical rates remains unknown.

AREAS TIMELY FOR DEVELOPING RESEARCH

Clinical translational work is needed to identify novel pathways in IBD pathogenesis that sub-select patients who would benefit by specific-cytokine pathway modulation.

New targets for mucosal healing and therapy in inflammatory bowel diseases

Healing of the inflamed mucosa (mucosal healing) is an emerging new goal for therapy and predicts clinical remission and resection-free survival in inflammatory bowel diseases (IBDs). The era of antitumor necrosis factor (TNF) antibody therapy was a remarkable progress in IBD therapy and anti-TNF agents led to mucosal healing in a subgroup of IBD patients; however, many patients do not respond to anti-TNF treatment highlighting the relevance of finding new targets for therapy of IBD. In particular, current studies are addressing the role of other anticytokine agents including antibodies against interleukin (IL)-6R, IL-13, and IL-12/IL-23 as well as new anti-inflammatory concepts (regulatory T cell therapy, Smad7 antisense, Jak inhibition, Toll-like receptor 9 stimulation, worm eggs). In addition, blockade of T-cell homing via the integrins α4β7 and the addressin mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) emerges as a promising new approach for IBD therapy. Here, new approaches for achieving mucosal healing are discussed as well as their implications for future therapy of IBD.

The value of experimental models of colitis in predicting efficacy of biological therapies for inflammatory bowel diseases

During the last decade, biological therapies have an increasing share in the modern therapeutics of various diseases including inflammatory bowel diseases (IBD). Animal models of IBD have often been used to identify the targets of biological therapies, to test their relevance to disease pathogenesis, to assess their therapeutic efficacy in vivo, and to check for drug toxicity. In the field of inflammatory diseases the majority of biologics under development have failed to reach the clinic. This review examines the ability of preclinical data from animal models of IBD to predict success or failure of biologics in human IBD. Specifically, it describes the murine models of IBD, the mechanism of disease induction, the phenotype of the disease, its relevance to human IBD, and the specific immunological features of disease pathogenesis in each model and mainly compares the results of the phase II and III trials of biologics in IBD with preclinical data obtained from studies in animal models. Finally, it examines the possible reasons for low success in translation from bench to bedside and offers some suggestions to improve translation rates.

Animal models of ulcerative colitis and their application in drug research

The specific pathogenesis underlying inflammatory bowel disease is complex, and it is even more difficult to decipher the pathophysiology to explain for the similarities and differences between two of its major subtypes, Crohn's disease and ulcerative colitis (UC). Animal models are indispensable to pry into mechanistic details that will facilitate better preclinical drug/therapy design to target specific components involved in the disease pathogenesis. This review focuses on common animal models that are particularly useful for the study of UC and its therapeutic strategy. Recent reports of the latest compounds, therapeutic strategies, and approaches tested on UC animal models are also discussed.

Animal models of ulcerative colitis and their application in drug research

The specific pathogenesis underlying inflammatory bowel disease is complex, and it is even more difficult to decipher the pathophysiology to explain for the similarities and differences between two of its major subtypes, Crohn's disease and ulcerative colitis (UC). Animal models are indispensable to pry into mechanistic details that will facilitate better preclinical drug/therapy design to target specific components involved in the disease pathogenesis. This review focuses on common animal models that are particularly useful for the study of UC and its therapeutic strategy. Recent reports of the latest compounds, therapeutic strategies, and approaches tested on UC animal models are also discussed.

Advances in therapeutic interventions targeting the vascular and lymphatic endothelium in inflammatory bowel disease

PURPOSE OF REVIEW

The review summarizes the current knowledge of the roles played by the vascular and lymphatic endothelium throughout the gut in the pathogenesis of inflammatory bowel disease (IBD) and gives an update on emerging strategies targeting both vasculatures.

RECENT FINDINGS

Enormous efforts have been made to understand the mechanisms underlining the origin, development and maintenance of intestinal chronic inflammation. In particular, new studies focused their attention on the role played by the microvascular and lymphatic endothelium in the pathogenesis of IBD. During inflammation, whereas the microvasculature is responsible for the entry and distribution of immune cells in the mucosa, the lymphatic system controls leukocyte exit, bacterial clearance and edema absorption. The study of these events, which are aberrant during chronic inflammation, has resulted in the identification and validation of several targets for the treatment of experimental colitis, some of which have translated into effective treatments for patients with IBD.

SUMMARY

Although much attention has been paid to the microvascular endothelium and to antiangiogenic therapies, specific studies on the lymphatic vasculature and its functions in IBD are still at the initial stage, and other molecular mechanisms, genes, molecules and new pathways must definitely be explored.

Leukocyte traffic blockade as a therapeutic strategy in inflammatory bowel disease

Dysregulated recruitment of leukocytes into the intestine is a characteristic feature of IBD. Several families of molecules regulate the influx of these cells into sites of inflammation within the gastrointestinal tract. Pharmacological blockade of interactions between molecules that mediate the formation of stable bonds (integrins) and their endothelial ligands has already shown clinical efficacy. Antibodies that target participant molecules have been approved by the US Federal Drug Administration for use in Crohn's, multiple sclerosis (MS) (i.e. natalizumab) and psoriasis (i.e. efalizumab). A more recent additional family of drugs, which might also interfere with lymphocyte traffic (i.e. sphingosine-1- phosphate receptor agonists: fingolimod) is in clinical use for MS and just recently entered the clinical trial stage for ulcerative colitis. In the present review we discuss basic aspects of clinically relevant molecules and compile the clinical studies that support the targeting of specific steps of the leukocyte adhesion cascade for therapeutic purposes in IBD.

Novel treatment options for ulcerative colitis

The approved treatment options for patients with ulcerative colitis (UC) are currently limited to mesalamine or immunosuppressants. Patients who do not respond to mesalamine-based therapy can be treated with immunomodulators or anti-TNF antibody therapy. Failure or adverse reactions to these medications leaves the patient with little choice other than colectomy. However, novel insights into the pathogenic drivers of UC have led to new developments in drugs that promise clinical efficacy via modulation of targeted pathways. Given the impending expansion of therapeutic options for patients with UC, clinicians and researchers should be familiar with these mechanisms of action. In addition, the typical 'step-up' treatment paradigm for UC will likely need to be reshaped to allow for a more personalized approach to treating UC.