A phase II dose ranging, double-blind, placebo-controlled study of alicaforsen enema in subjects with acute exacerbation of mild to moderate left-sided ulcerative colitis

Understanding the molecular mechanisms of anti-trafficking therapies and their clinical relevance in inflammatory bowel disease

In patients with inflammatory bowel disease (IBD), a combination of dysbiosis, increased intestinal permeability, and insufficient regulatory responses facilitate the development of chronic inflammation, which is driven by a complex interplay between the mucosal immune system and the environment and sustained by immune priming and ongoing cellular recruitment to the gut. The localization of immune cells is mediated by their expression of chemokine receptors and integrins, which bind to chemokines and adhesion molecules, respectively. In this article, we review the mechanisms of action of anti-trafficking therapies for IBD and consider clinical observations in the context of the different mechanisms of action. Furthermore, we discuss the evolution of molecular resistance to anti-cytokines, in which the composition of immune cells in the gut changes in response to treatment, and the potential implications of this for treatment sequencing. Lastly, we discuss the relevance of mechanism of action to combination therapy for IBD.

Circular and Circulating DNA in Inflammatory Bowel Disease: From Pathogenesis to Potential Molecular Therapies

Inflammatory bowel diseases (IBD), including Crohn's Disease (CD) and Ulcerative Colitis (UC) are chronic multifactorial disorders which affect the gastrointestinal tract with variable extent. Despite extensive research, their etiology and exact pathogenesis are still unknown. Cell-free DNAs (cfDNAs) are defined as any DNA fragments which are free from the origin cell and able to circulate into the bloodstream with or without microvescicles. CfDNAs are now being increasingly studied in different human diseases, like cancer or inflammatory diseases. However, to date it is unclear how IBD etiology is linked to cfDNAs in plasma. Extrachromosomal circular DNA (eccDNA) are non-plasmidic, nuclear, circular and closed DNA molecules found in all eukaryotes tested. CfDNAs appear to play an important role in autoimmune diseases, inflammatory processes, and cancer; recently, interest has also grown in IBD, and their role in the pathogenesis of IBD has been suggested. We now suggest that eccDNAs also play a role in IBD. In this review, we have comprehensively collected available knowledge in literature regarding cfDNA, eccDNA, and structures involving them such as neutrophil extracellular traps and exosomes, and their role in IBD. Finally, we focused on old and novel potential molecular therapies and drug delivery systems, such as nanoparticles, for IBD treatment.

Novel Small Molecules in IBD: Current State and Future Perspectives

Biologicals have dominated the therapeutic scenery in inflammatory bowel diseases (IBDs), namely ulcerative colitis (UC) and Crohn's disease (CD), for the past 20 years. The development of tofacitinib was the starting point for an era of small molecules after the era of biologicals. These new agents may challenge the use of biological agents in the future. They share properties that appeal to both patients and physicians. Low production costs, a lack of immunogenicity, and ease of use are only some of their benefits. On the other hand, patients and their physicians must manage the potential side effects of small molecules such as JAK inhibitors or S1P1R modulators. Here, we present agents that have already entered the clinical routine and those that are still being investigated in clinical trials.

The Role of the Lymphatic System in the Pathogenesis and Treatment of Inflammatory Bowel Disease

Although the number of therapeutic options for the treatment of inflammatory bowel disease (IBD) has increased in recent years, patients suffer from decreased quality of life due to non-response or loss of response to the currently available treatments. An increased understanding of the disease’s etiology could provide novel insights for treatment strategies in IBD. Lymphatic system components are generally linked to immune responses and presumably related to inflammatory diseases pathophysiology. This review aims to summarize findings on immune-mediated mechanisms in lymphoid tissues linked with IBD pathogenesis and (potential) novel treatments. Enhanced innate and adaptive immune responses were observed in mesenteric lymph nodes (MLNs) and other lymphoid structures, such as Peyer’s patches, in patients with IBD and in animal models. Furthermore, the phenomenon of lymphatic obstruction in the form of granulomas in MLNs and lymphatic vessels correlates with disease activity. There is also evidence that abnormalities in the lymphatic stromal components and lymph node microbiome are common in IBD and could be exploited therapeutically. Finally, novel agents targeting lymphocyte trafficking have been added to the treatment armamentarium in the field of IBD. Overall, gut-associated lymphoid tissue plays a key role in IBD immunopathogenesis, which could offer novel therapeutic targets.

Emerging therapeutic options in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic disease that requires chronic treatment throughout the evolution of the disease, with a complex physiopathology that entails great challenges for the development of new and specific treatments for ulcerative colitis and Crohn´s disease. The anti-tumor necrosis factor alpha therapy has impacted the clinical course of IBD in those patients who do not respond to conventional treatment, so there is a need to develop new therapies and markers of treatment response. Various pathways involved in the development of the disease are known and the new therapies have focused on blocking the inflammatory process at the gastrointestinal level by oral, intravenous, subcutaneous, and topical route. All these new therapies can lead to more personalized treatments with higher success rates and fewer relapses. These treatments have not only focused on clinical remission, but also on achieving macroscopic changes at the endoscopic level and microscopic changes by achieving mucosal healing. These treatments are mainly based on modifying signaling pathways, by blocking receptors or ligands, reducing cell migration and maintaining the integrity of the epithelial barrier. Therefore, this review presents the efficacy and safety of the new treatments that are currently under study and the advances that have been made in this area in recent years.

New agents for immunosuppression

The human abdomen harbors organs that the host's immune system can attack easily. This immunological storm front leads to diseases like Crohn's Disease, Ulcerative Colitis or Autoimmune Hepatitis. Serious symptoms like pain, diarrhea, fatigue, or malnutrition accompany these diseases. Moreover, many patients have an increased risk for developing special kind of malignancies and some autoimmune disease can show a high mortality. The key to treat them consists of a deep understanding of their pathophysiology. In vitro and especially in vivo basic research laid the foundation for our increasing knowledge about it during the past years. This enabled the development of new therapeutic approaches that interact directly with cytokines or immune cells instead of building the treatment on a total immunosuppression. Different kind of antibodies, kinase inhibitors, and regulatory T cells build the base for these approaches. This review shows new therapeutical approaches in gastrointestinal autoimmune diseases in context to their pathophysiological basis.

Immunohistochemical Study of Adhesion Molecules in Irritable Bowel Syndrome: A Comparison to Inflammatory Bowel Diseases

Background:

The surface of endothelial cells is covered with cell adhesion molecules including E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1) that mediate the adhesion and extravasation of leukocytes and play a pivotal role in inflammatory response. The aim of this study was to investigate the role of expression of adhesion molecules in inflammatory bowel disease (IBD) patients, irritable bowel syndrome (IBS) patients, and normal colonic mucosa.

Materials and Methods:

IBS and IBD patients along with normal colonic mucosa were recruited in the study. In all groups, two biopsies were taken from each of the three anatomical sites (terminal ileum, cecum, and rectum). Three monoclonal antibodies, E-selectin mAb, VCAM-1 mAb, and ICAM-1 mAb, were applied for immunohistochemical analysis.

Results:

In IBD patients, the expression of intensity of E-selectin, VCAM-1, and ICAM-1 was found decreased, at least in cecum and rectum, in comparison with IBS patients and controls (P < 0.001, P < 0.005, and P < 0.007, respectively). Comparison of the expression of intensity of the aforementioned molecules in IBS patients and controls revealed significant augmentation at the cecum and rectum of IBS patients.

Conclusions:

The expression of adhesion molecules appeared lower in IBD patients compared to IBS patients and controls. In addition, the expression of adhesion molecules appeared higher in IBS compared to the control group. Therefore, it could be hypothesized that the expression of adhesion molecules could be considered as an early event in the process of proinflammatory IBS group and may be other factors play a crucial role in the process of intestinal inflammation in IBD patients.

Emerging Treatment Options in Inflammatory Bowel Disease: Janus Kinases, Stem Cells, and More

BACKGROUND

Treatment of inflammatory bowel diseases (IBD) has tremendously improved during the last 20 years; however, a substantial fraction of patients does not respond to available therapies or lose response, and new strategies are needed.

SUMMARY

Two pharmacological principles have been successfully used for IBD treatment: inhibition of cellular signaling and interference with leukocyte trafficking. Besides tumor necrosis factor, interleukin (IL)-23 is a promising drug target, and antibodies for the combined inhibition of IL-23 and IL-12 (ustekinumab and briakinumab) or selective IL-23 inhibition (brazikumab, risankizumab, and mirikizumab) seem to be effective in Crohn's disease (CD) with emerging evidence also for ulcerative colitis (UC). Janus kinase (JAK) mediates intracellular signaling of a large number of cytokines. Tofacitinib is the first JAK inhibitor approved for UC, and the JAK inhibitors filgotinib and upadacitinib showed potential in CD. Leukocyte trafficking can be inhibited by interference with lymphocyte integrin-α4β7 or endothelial MadCAM-1. The α4β7 integrin inhibitor vedolizumab is an established treatment in IBD, and long-term data of pivotal studies are now available. Additional molecules with therapeutic potential are α4β7-specific abrilumab, β7-specific etrolizumab, and the α4-specific small molecule AJM300. PF-00547659, an antibody against endothelial MadCAM-1, also showed therapeutic potential in UC. Modulation of sphingosine-1-phosphate receptor (S1PR) activity is necessary for the egress of lymphocytes into the circulation, and S1PR modulation results in lymphocyte trapping in lymphatic organs. Ozanimod, an S1PR1 and S1PR5 inhibitor, has been successfully tested in initial studies in UC. Mesenchymal stem cell therapy has been approved for the treatment of complex, active CD fistula, and mesenchymal stem cell therapy might be a paradigm shift for this condition. Autologous stem cell transplantation (ASCT) has been successfully used in CD case series; however, in a randomized trial, a highly stringent endpoint was not met. However, considering positive effects in secondary endpoints, ASCT might be a future treatment of last resort in severe, refractory CD cases, provided that safer protocols can be provided. Key messages: New IBD treatments are successful for a significant fraction of patients. However, new strategies for patient selection, treatment combinations, and/or additional therapies must be developed to serve the need of all IBD patients.

Targeting Immune Cell Trafficking - Insights From Research Models and Implications for Future IBD Therapy

Inflammatory bowel diseases (IBDs), including Crohn's disease (CD) and ulcerative colitis (UC) are multifactorial diseases with still unknown aetiology and an increasing prevalence and incidence worldwide. Despite plentiful therapeutic options for IBDs, the lack or loss of response in certain patients demands the development of further treatments to tackle this unmet medical need. In recent years, the success of the anti-α4β7 antibody vedolizumab highlighted the potential of targeting the homing of immune cells, which is now an important pillar of IBD therapy. Due to its complexity, leukocyte trafficking and the involved molecules offer a largely untapped resource for a plethora of potential therapeutic interventions. In this review, we aim to summarise current and future directions of specifically interfering with immune cell trafficking. We will comment on concepts of homing, retention and recirculation and particularly focus on the role of tissue-derived chemokines. Moreover, we will give an overview of the mode of action of drugs currently in use or still in the pipeline, highlighting their mechanisms and potential to reduce disease burden.

Antisense Oligonucleotides: An Emerging Area in Drug Discovery and Development

Antisense oligonucleotides (ASOs) bind sequence specifically to the target RNA and modulate protein expression through several different mechanisms. The ASO field is an emerging area of drug development that targets the disease source at the RNA level and offers a promising alternative to therapies targeting downstream processes. To translate ASO-based therapies into a clinical success, it is crucial to overcome the challenges associated with off-target side effects and insufficient biological activity. In this regard, several chemical modifications and diverse delivery strategies have been explored. In this review, we systematically discuss the chemical modifications, mechanism of action, and optimized delivery strategies of several different classes of ASOs. Further, we highlight the recent advances made in development of ASO-based drugs with a focus on drugs that are approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for clinical applications. We also discuss various promising ASO-based drug candidates in the clinical trials, and the outstanding opportunity of emerging microRNA as a viable therapeutic target for future ASO-based therapies.

Controlling leukocyte trafficking in IBD

Inflammatory bowel disease (IBD) is characterized by the accumulation of immune cells, myeloid cells and lymphocytes in the inflamed intestine. The presence and persistence of these cells, together with the production of pro-inflammatory mediators, perpetuate intestinal inflammation in both ulcerative colitis and Crohn's disease. Thus, blockade of leukocyte migration to the intestine is a main strategy used to control the disease and alleviate symptoms. Vedolizumab is the only anti-integrin drug approved for the treatment of IBD but several other drugs also targeting integrins, chemokines or receptors involved in leukocyte intestinal trafficking are under development and investigated for their efficacy and safety in IBD. The challenge now is to better understand the specific mechanism of action underlying each drug and to identify biomarkers that would guide drug selection in the individual patient.

Therapeutic Oligonucleotides for Patients with Inflammatory Bowel Diseases

Introduction

The better understanding of the molecular mechanisms, which drive the pathological process in the gut of patients with Crohn's disease (CD) and patients with ulcerative colitis (UC), the major forms of inflammatory bowel diseases (IBD) in humans, has facilitated the development of novel therapeutic compounds. Among these, antisense oligonucleotides (ASOs) have been used to inhibit the expression of molecules, which sustain the IBD-associated mucosal inflammation.

Areas Covered

In this short review, we summarize experimental and clinical data on the use of ASOs in IBD.

Expert Opinion

Preclinical work indicates that the modulation of specific inflammatory pathways through the use of ASOs is highly effective and associates with low risk of adverse events. Initial clinical studies have confirmed the benefit of some ASOs even though no compound has yet reached the market. Further experimentation is warranted to establish the optimal route of administration for each ASO, ascertain whether and how long ASOs maintain their activity following administration, and identify which patient can benefit from specific ASO treatment.

Treatment and prevention of pouchitis after ileal pouch-anal anastomosis for chronic ulcerative colitis

BACKGROUND

Pouchitis occurs in approximately 50% of patients following ileal pouch-anal anastomosis (IPAA) for chronic ulcerative colitis (UC).

OBJECTIVES

The primary objective was to determine the efficacy and safety of medical therapies for prevention or treatment of acute or chronic pouchitis.

SEARCH METHODS

We searched MEDLINE, Embase and CENTRAL from inception to 25 July 2018. We also searched references, trials registers, and conference proceedings.

SELECTION CRITERIA

Randomized controlled trials of prevention or treatment of acute or chronic pouchitis in adults who underwent IPAA for UC were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently screened studies for eligibility, extracted data and assessed the risk of bias. The certainty of the evidence was evaluated using GRADE. The primary outcome was clinical improvement or remission in participants with acute or chronic pouchitis, or the proportion of participants with no episodes of pouchitis after IPAA. Adverse events (AEs) was a secondary outcome. We calculated the risk ratio (RR) and corresponding 95% confidence interval (CI) for each dichotomous outcome.

MAIN RESULTS

Fifteen studies (547 participants) were included. Four studies assessed treatment of acute pouchitis. Five studies assessed treatment of chronic pouchitis. Six studies assessed prevention of pouchitis. Three studies were low risk of bias. Three studies were high risk of bias and the other studies were unclear. Acute pouchitis: All ciprofloxacin participants (7/7) achieved remission at two weeks compared to 33% (3/9) of metronidazole participants (RR 2.68, 95% CI 1.13 to 6.35, very low certainty evidence). No ciprofloxacin participants (0/7) had an AE compared to 33% (3/9) of metronidazole participants (RR 0.18, 95% CI 0.01 to 2.98; very low certainty evidence). AEs included vomiting, dysgeusia or transient peripheral neuropathy. Forty-three per cent (6/14) of metronidazole participants achieved remission at 6 weeks compared to 50% (6/12) of budesonide enema participants (RR 0.86, 95% CI 0.37 to 1.96, very low certainty evidence). Fifty per cent (7/14) of metronidazole participants improved clinically at 6 weeks compared to 58% (7/12) of budesonide enema participants (RR 0.86, 95% CI 0.42 to 1.74, very low certainty evidence). Fifty-seven per cent (8/14) of metronidazole participants had an AE compared to 25% (3/12) of budesonide enema participants (RR 2.29, 95% CI 0.78 to 6.73, very low certainty evidence). AEs included anorexia, nausea, headache, asthenia, metallic taste, vomiting, paraesthesia, and depression. Twenty-five per cent (2/8) of rifaximin participants achieved remission at 4 weeks compared to 0% (0/10) of placebo participants (RR 6.11, 95% CI 0.33 to 111.71, very low certainty evidence). Thirty-eight per cent (3/8) of rifaximin participants improved clinically at 4 weeks compared to 30% (3/10) of placebo participants (RR 1.25, 95% CI 0.34 to 4.60, very low certainty evidence). Seventy-five per cent (6/8) of rifaximin participants had an AE compared to 50% (5/10) of placebo participants (RR 1.50, 95% CI 0.72 to 3.14, very low certainty evidence). AEs included diarrhea, flatulence, nausea, proctalgia, vomiting, thirst, candida, upper respiratory tract infection, increased hepatic enzyme, and cluster headache. Ten per cent (1/10) of Lactobacillus GG participants improved clinically at 12 weeks compared to 0% (0/10) of placebo participants (RR 3.00, 95% CI 0.14 to 65.90, very low certainty evidence). Chronic pouchitis: Eighty-five per cent (34/40) of De Simone Formulation (a probiotic formulation) participants maintained remission at 9 to 12 months compared to 3% (1/36) of placebo participants (RR 20.24, 95% CI 4.28 to 95.81, 2 studies; low certainty evidence). Two per cent (1/40) of De Simone Formulation participants had an AE compared to 0% (0/36) of placebo participants (RR 2.43, 95% CI 0.11 to 55.89; low certainty evidence). AEs included abdominal cramps, vomiting and diarrhea. Fifty per cent (3/6) of adalimumab patients achieved clinical improvement at 4 weeks compared to 43% (3/7) of placebo participants (RR, 1.17, 95% CI 0.36 to 3.76, low certainty evidence). Sixty per cent (6/10) of glutamine participants maintained remission at 3 weeks compared to 33% (3/9) of butyrate participants (RR 1.80, 95% CI 0.63 to 5.16, very low certainty evidence). Forty-five per cent (9/20) of patients treated with bismuth carbomer foam enema improved clinically at 3 weeks compared to 45% (9/20) of placebo participants (RR 1.00, 95% CI 0.50 to 1.98, very low certainty evidence). Twenty-five per cent (5/20) of participants in the bismuth carbomer foam enema group had an AE compared to 35% (7/20) of placebo participants (RR 0.71, 95% CI 0.27 to 1.88, very low certainty evidence). Adverse events included diarrhea, worsening symptoms, cramping, sinusitis, and abdominal pain.

PREVENTION

At 12 months, 90% (18/20) of De Simone Formulation participants had no episodes of acute pouchitis compared to 60% (12/20) of placebo participants (RR 1.50, 95% CI 1.02 to 2.21, low certainty evidence). Another study found 100% (16/16) of De Simone Formulation participants had no episodes of acute pouchitis at 12 months compared to 92% (11/12) of the no treatment control group (RR 1.10, 95% 0.89 to 1.36, very low certainty evidence). Eighty-six per cent (6/7) of Bifidobacterium longum participants had no episodes of acute pouchitis at 6 months compared to 60% (3/5) of placebo participants (RR 1.43, 95% CI 0.66 to 3.11, very low certainty evidence). Eleven per cent (1/9) of Clostridium butyricum MIYAIRI participants had no episodes of acute pouchitis at 24 months compared to 50% (4/8) of placebo participants (RR 0.22, 95% CI 0.03 to 1.60, very low certainty evidence). Forty-six per cent (43/94) of allopurinol participants had no episodes of pouchitis at 24 months compared to 43% (39/90) of placebo participants (RR 1.06, 95% CI 0.76 to 1.46; low certainty evidence). Eighty-one per cent (21/26) of tinidazole participants had no episodes of pouchitis over 12 months compared to 58% (7/12) of placebo participants (RR 1.38, 95% CI 0.83 to 2.31, very low certainty evidence).

AUTHORS' CONCLUSIONS

The effects of antibiotics, probiotics and other interventions for treating and preventing pouchitis are uncertain. Well designed, adequately powered studies are needed to determine the optimal therapy for the treatment and prevention of pouchitis.

Anti-trafficking agents in the treatment of inflammatory bowel disease

PURPOSE OF REVIEW

To describe the latest developments in the field of anti-trafficking agents (ATAs), a class of therapeutics with growing importance in the field of inflammatory bowel diseases (IBDs) that specifically inhibit steps of immune cell trafficking.

RECENT FINDINGS

Several translational and clinical studies have further shaped the knowledge about the mechanisms and effects of the anti-α4β7 integrin antibody vedolizumab. In parallel, new ATAs like the anti-β7 integrin antibody etrolizumab and the anti-MAdCAM-1 antibody ontamalimab are investigated in phase III clinical trials and might soon increase the therapeutic armamentarium in IBD.

SUMMARY

ATAs have unique mechanisms of action and can meanwhile be considered an indispensable column of IBD therapy. Further efforts are necessary to elucidate complex mechanistic aspects, to exactly define their role in relation to other therapeutic approaches and to identify novel treatment targets as well as biomarkers for personalized medicine.

Treatment and prevention of pouchitis after ileal pouch-anal anastomosis for chronic ulcerative colitis

BACKGROUND

Pouchitis occurs in approximately 50% of patients following ileal pouch-anal anastomosis (IPAA) for chronic ulcerative colitis (UC).

OBJECTIVES

The primary objective was to determine the efficacy and safety of medical therapies for prevention or treatment of acute or chronic pouchitis.

SEARCH METHODS

We searched MEDLINE, Embase and CENTRAL from inception to 25 July 2018. We also searched references, trials registers, and conference proceedings.

SELECTION CRITERIA

Randomized controlled trials of prevention or treatment of acute or chronic pouchitis in adults who underwent IPAA for UC were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently screened studies for eligibility, extracted data and assessed the risk of bias. The certainty of the evidence was evaluated using GRADE. The primary outcome was clinical improvement or remission in participants with acute or chronic pouchitis, or the proportion of participants with no episodes of pouchitis after IPAA. Adverse events (AEs) was a secondary outcome. We calculated the risk ratio (RR) and corresponding 95% confidence interval (CI) for each dichotomous outcome.

MAIN RESULTS

Fifteen studies (547 participants) were included. Four studies assessed treatment of acute pouchitis. Five studies assessed treatment of chronic pouchitis. Six studies assessed prevention of pouchitis. Three studies were low risk of bias. Three studies were high risk of bias and the other studies were unclear.Acute pouchitis: All ciprofloxacin participants (7/7) achieved remission at two weeks compared to 33% (3/9) of metronidazole participants (RR 2.68, 95% CI 1.13 to 6.35, very low certainty evidence). No ciprofloxacin participants (0/7) had an AE compared to 33% (3/9) of metronidazole participants (RR 0.18, 95% CI 0.01 to 2.98; very low certainty evidence). AEs included vomiting, dysgeusia or transient peripheral neuropathy. Forty-three per cent (6/14) of metronidazole participants achieved remission at 6 weeks compared to 50% (6/12) of budesonide enema participants (RR 0.86, 95% CI 0.37 to 1.96, very low certainty evidence). Fifty per cent (7/14) of metronidazole participants improved clinically at 6 weeks compared to 58% (7/12) of budesonide enema participants (RR 0.86, 95% CI 0.42 to 1.74, very low certainty evidence). Fifty-seven per cent (8/14) of metronidazole participants had an AE compared to 25% (3/12) of budesonide enema participants (RR 2.29, 95% CI 0.78 to 6.73, very low certainty evidence). AEs included anorexia, nausea, headache, asthenia, metallic taste, vomiting, paraesthesia, and depression. Twenty-five per cent (2/8) of rifaximin participants achieved remission at 4 weeks compared to 0% (0/10) of placebo participants (RR 6.11, 95% CI 0.33 to 111.71, very low certainty evidence). Thirty-eight per cent (3/8) of rifaximin participants improved clinically at 4 weeks compared to 30% (3/10) of placebo participants (RR 1.25, 95% CI 0.34 to 4.60, very low certainty evidence). Seventy-five per cent (6/8) of rifaximin participants had an AE compared to 50% (5/10) of placebo participants (RR 1.50, 95% CI 0.72 to 3.14, very low certainty evidence). AEs included diarrhea, flatulence, nausea, proctalgia, vomiting, thirst, candida, upper respiratory tract infection, increased hepatic enzyme, and cluster headache. Ten per cent (1/10) of Lactobacillus GG participants improved clinically at 12 weeks compared to 0% (0/10) of placebo participants (RR 3.00, 95% CI 0.14 to 65.90, very low certainty evidence).Chronic pouchitis: Eighty-five per cent (34/40) of De Simone Formulation participants maintained remission at 9 to 12 months compared to 3% (1/36) of placebo participants (RR 20.24, 95% CI 4.28 to 95.81, 2 studies; low certainty evidence). Two per cent (1/40) of De Simone Formulation participants had an AE compared to 0% (0/36) of placebo participants (RR 2.43, 95% CI 0.11 to 55.89; low certainty evidence). AEs included abdominal cramps, vomiting and diarrhea. Fifty per cent (3/6) of adalimumab patients achieved clinical improvement at 4 weeks compared to 43% (3/7) of placebo participants (RR, 1.17, 95% CI 0.36 to 3.76, low certainty evidence). Sixty per cent (6/10) of glutamine participants maintained remission at 3 weeks compared to 33% (3/9) of butyrate participants (RR 1.80, 95% CI 0.63 to 5.16, very low certainty evidence). Forty-five per cent (9/20) of patients treated with bismuth carbomer foam enema improved clinically at 3 weeks compared to 45% (9/20) of placebo participants (RR 1.00, 95% CI 0.50 to 1.98, very low certainty evidence). Twenty-five per cent (5/20) of participants in the bismuth carbomer foam enema group had an AE compared to 35% (7/20) of placebo participants (RR 0.71, 95% CI 0.27 to 1.88, very low certainty evidence). Adverse events included diarrhea, worsening symptoms, cramping, sinusitis, and abdominal pain.

PREVENTION

At 12 months, 90% (18/20) of De Simone Formulation participants had no episodes of acute pouchitis compared to 60% (12/20) of placebo participants (RR 1.50, 95% CI 1.02 to 2.21, low certainty evidence). Another study found 100% (16/16) of De Simone Formulation participants had no episodes of acute pouchitis at 12 months compared to 92% (11/12) of the no treatment control group (RR 1.10, 95% 0.89 to 1.36, very low certainty evidence). Eighty-six per cent (6/7) of Bifidobacterium longum participants had no episodes of acute pouchitis at 6 months compared to 60% (3/5) of placebo participants (RR 1.43, 95% CI 0.66 to 3.11, very low certainty evidence). Eleven per cent (1/9) of Clostridium butyricum MIYAIRI participants had no episodes of acute pouchitis at 24 months compared to 50% (4/8) of placebo participants (RR 0.22, 95% CI 0.03 to 1.60, very low certainty evidence). Forty-six per cent (43/94) of allopurinol participants had no episodes of pouchitis at 24 months compared to 43% (39/90) of placebo participants (RR 1.06, 95% CI 0.76 to 1.46; low certainty evidence). Eighty-one per cent (21/26) of tinidazole participants had no episodes of pouchitis over 12 months compared to 58% (7/12) of placebo participants (RR 1.38, 95% CI 0.83 to 2.31, very low certainty evidence).

AUTHORS' CONCLUSIONS

The effects of antibiotics, probiotics and other interventions for treating and preventing pouchitis are uncertain. Well designed, adequately powered studies are needed to determine the optimal therapy for the treatment and prevention of pouchitis.

Oligonucleotides-A Novel Promising Therapeutic Option for IBD

Inflammatory Bowel Diseases (IBD), whose denomination comprehends Crohn's Disease (CD) and Ulcerative Colitis (UC), are intestinal chronic diseases that often require lifelong medical therapy. In the last two decades monoclonal antibodies against the cytokine TNF have become integral parts in the treatment of IBD patients, however there are unwanted side-effects and one third of patients show primary non-response while another subgroup loses response over time. Finding novel drugs which could act as therapies against precise pro-inflammatory molecular targets to avoid unwanted systemic side effects and additionally the process of immunization, represents an important aim for subsequent therapeutic approaches. Oligonucleotide based therapies represent a promising novel concept for the treatment of IBD. The molecular action of oligonucleotides ranges from inhibition of the translational process of mRNA transcripts of pro-inflammatory molecules, to mimicking bacterial DNA which can activate cellular targets for immunomodulation. Alicaforsen, selectively targets ICAM-1 mRNA. ICAM-1 is an adhesion molecule which is upregulated on endothelial cells during IBD, thereby mediating the adhesion and migration of leucocytes from blood to sites of active inflammation. In CD parenteral application of alicaforsen did not show therapeutic efficacy in phase II trials, but it demonstrated an improved efficacy as a topical enema in distal UC. Topical application of alicaforsen might represent a therapeutic perspective for refractory pouchitis as well. SMAD7 is a protein that inhibits the signaling of TGFβ, which is the mainstay of a regulatory counterpart in cellular immune responses. An antisense oligonucleotide against SMAD7 mRNA (mongersen) demonstrated pre-clinical and phase II efficacy in CD, but a phase III clinical trial was stopped due to lack of efficacy. Cobitolimod is a single strand oligonucleotide, which mimics bacterial DNA as its CpG dinucleotide sequences can be recognized by the Toll-like receptor 9 on different immune cells thereby causing induction of different cytokines, for example IL10 and IFNα. Topical application of cobitolimod was studied in UC patients. We will also discuss two other novel oligonucleotides which act on the GATA3 transcription factor (SB012) and on carbohydrate sulfotransferase 15 (STNM01), which could both represent novel promising therapeutic options for the treatment of UC.

Novel Non-biologic Targets for Inflammatory Bowel Disease

PURPOSE OF REVIEW

The biologic era revolutionized the medical management of inflammatory bowel disease (IBD) and allowed for a paradigm shift away from a therapeutic strategy that traditionally relied on corticosteroids and immunomodulators. IBD treatment has now further evolved to encompass novel non-biologic agents.

RECENT FINDINGS

An electronic database search, spanning up to September 2018, was conducted using PubMed, Web of Science, Google Scholar, and Scopus. Abstracts were also reviewed from Digestive Diseases Week, European Crohn's and Colitis Organization congress, Canadian Digestive Diseases Week, and United European Gastroenterology Week. The JAK1/3 inhibitor, tofacitinib, was shown to both induce and maintain clinical remission and mucosal healing in ulcerative colitis (UC). Also, the sphingosine-1-phosphate (SIP) S1P1/S1P5 receptor agonist ozanimod showed benefit with clinical remission and mucosal healing in UC. Anti-trafficking non-biologic therapies such as AJM300 and a phosphodiesterase (PDE) PDE4 inhibitor, apremilast, have shown benefit in terms of clinical response, clinical remission, and mucosal healing in UC. Upadacitinib and filgotinib have shown initial favorable outcomes in CD patients, with further ongoing trials. Non-biologic agents comprise a growing number of mechanisms of action with the promise of safe and effective oral therapy for patients with IBD.

Antisense Oligonucleotide: Basic Concepts and Therapeutic Application in Inflammatory Bowel Disease

Several molecular technologies aimed at regulating gene expression that have been recently developed as a strategy to combat inflammatory and neoplastic diseases. Among these, antisense technology is a specific, rapid, and potentially high-throughput approach for inhibiting gene expression through recognition of cellular RNAs. Advances in the understanding of the molecular mechanisms that drive tissue damage in different inflammatory diseases, including Crohn's disease (CD) and ulcerative colitis (UC), the two major inflammatory bowel diseases (IBDs) in humans, have facilitated the identification of novel druggable targets and offered interesting therapeutic perspectives for the treatment of patients. This short review provides a comprehensive understanding of the basic concepts underlying the mechanism of action of the oligonucleotide therapeutics, and summarizes the available pre-clinical and clinical data for oligonucleotide-based therapy in IBD.

Anti-adhesion Molecules in IBD: Does Gut Selectivity Really Make the Difference?

Inflammatory Bowel Disease is lifetime chronic progressive inflammatory disease. A considerable portion of patients, do not respond or lose response or experience side effect to "traditional" biological treatment such as anti-tumor necrosis factor (TNF)-α agents. The concept that the blockade of T cell traffic to the gut controls inflammation has stimulated the development of new drugs which selectively targets molecules involved in controlling cell homing to the intestine. The result is the reduction of the chronic inflammatory infiltration in the gut. In this regard, anti-adhesion molecules represent a new class of drugs for patients who don't respond or lose response to traditional therapy. Moreover, some of these molecules such as vedolizumab, offer the advantage to target the delivery of a drug to the gut (gut selectivity) which could increase clinical efficacy and limit potential adverse events. In this article, we will give an overview of the current data on anti-adhesion molecules in Inflammatory Bowel Diseases.

Systematic review with meta-analysis: high prevalence and cost of continued aminosalicylate use in patients with ulcerative colitis escalated to immunosuppressive and biological therapies

BACKGROUND

Aminosalicylates are the most frequently prescribed treatment for ulcerative colitis (UC). In the absence of empirical evidence, clinicians are uncertain whether to continue aminosalicylates in patients with UC after escalating therapy.

AIMS

To quantify concomitant aminosalicylate use in UC randomised clinical trials (RCTs), identify factors associated with their use, and estimate treatment costs of concomitant aminosalicylate therapy.

METHODS

MEDLINE, Embase, and CENTRAL were searched from inception to 1 March 2017 for placebo-controlled RCTs of immunosuppressants, biologics, or oral small molecules in adults with UC. The proportion of patients prescribed concomitant aminosalicylates at trial entry was pooled using a random-effects model. Meta-regression was performed to assess trial-level factors associated with aminosalicylate use. Treatment costs were estimated using 2018 formulary data from five Canadian provinces.

RESULTS

Thirty-two trials were included (23 induction only, nine induction, and maintenance trials). The pooled proportion of patients co-prescribed aminosalicylates was 80.7% (95% CI 75.5%-85.1%), with considerable observed heterogeneity (I²  = 95%). In univariable meta-regression, aminosalicylate use was not associated with trial design, setting, year of publication, disease severity, disease duration, or drug class. The estimated direct annual treatment cost of concomitant aminosalicylates is ~$20 million for the Canadian UC population, assuming conservative estimates of UC prevalence, aminosalicylate use and dose, and the lowest cost formulation.

CONCLUSIONS

Approximately 80% of UC patients entering clinical trials of immunosuppressants, biologics, or oral small molecules continue to use aminosalicylates. An RCT is needed to inform the benefits and harms of continuing vs stopping aminosalicylates in patients escalating therapy.

Cell Trafficking Interference in Inflammatory Bowel Disease: Therapeutic Interventions Based on Basic Pathogenesis Concepts

After 20 years of successful targeting of pro-inflammatory cytokines for the treatment of IBD, an alternative therapeutic strategy has emerged, based on several decades of advances in understanding the pathogenesis of IBD. The targeting of molecules involved in leukocyte traffic has recently become a safe and effective alternative. With 2 currently approved drugs (ie, natalizumab, vedolizumab) and several others in phase 3 trials (eg, etrolizumab, ozanimod, anti-MAdCAM-1), the blockade of trafficking molecules has firmly emerged as a new therapeutic era for IBD. We discuss the targets that have been explored in clinical trials: chemokines and its receptors (eg, IP10, CCR9), integrins (eg, natalizumab, AJM300, vedolizumab, and etrolizumab), and its endothelial ligands (MAdCAM-1, ICAM-1). We also discuss a distinct strategy that interferes with lymphocyte recirculation by blocking lymphocyte egress from lymph nodes (small molecule sphingosine-phosphate receptor [S1PR] agonists: fingolimod, ozanimod, etrasimod, amiselimod). Strategies on the horizon include additional small molecules, allosteric inhibitors that specifically bind to the active integrin form and nanovectors that allow for the use of RNA interference in the quest to modulate pro-inflammatory leukocyte trafficking in IBD.

Oligonucleotide-Based Therapies for Inflammatory Bowel Disease

The growing understanding of the immunopathogenesis of inflammatory bowel diseases (IBDs) has contributed to the identification of new targets whose expression/activity can be modulated for therapeutic purposes. Several approaches have been employed to develop selective pharmaceutical compounds; among these, antisense oligonucleotides (ASOs) or synthetic oligonucleotides represent a valid option for inhibiting or enhancing, respectively, the expression/function of molecules that have been implicated in the control of IBD-related inflammation. In this context, data have been accumulated for the following compounds: alicaforsen, an ASO targeting intercellular adhesion molecule-1, a transmembrane glycoprotein that regulates rolling and adhesion of leukocytes to inflamed intestine; DIMS0150 and BL-7040, two oligonucleotides that enhance Toll-like receptor-9 activity; Mongersen, an ASO that inhibits Smad7, thereby restoring transforming growth factor-β1/Smad-associated signaling; STNM01, a double-stranded RNA oligonucleotide silencing carbohydrate sulfotransferase, an enzyme involved in fibrogenic processes, and hgd40, a specific DNAzyme inhibiting expression of the transcription factor GATA3. In this article, we review the rationale and the available data relative to the use of these agents in IBD. Although pre-clinical and phase II trials in IBD support the use of oligonucleotide-based therapies for treating the pathogenic process occurring in the gut of patients with these disorders, further work is needed to establish whether and which patients can benefit from specific ASOs and identify biomarkers that could help optimize treatment.

Mouse genome-wide association studies and systems genetics uncover the genetic architecture associated with hepatic pharmacokinetic and pharmacodynamic properties of a constrained ethyl antisense oligonucleotide targeting Malat1

Antisense oligonucleotides (ASOs) have demonstrated variation of efficacy in patient populations. This has prompted our investigation into the contribution of genetic architecture to ASO pharmacokinetics (PK) and pharmacodynamics (PD). Genome wide association (GWA) and transcriptomic analysis in a hybrid mouse diversity panel (HMDP) were used to identify and validate novel genes involved in the uptake and efficacy of a single dose of a Malat1 constrained ethyl (cEt) modified ASO. The GWA of the HMDP identified two significant associations on chromosomes 4 and 10 with hepatic Malat1 ASO concentrations. Stabilin 2 (Stab2) and vesicle associated membrane protein 3 (Vamp3) were identified by cis-eQTL analysis. HMDP strains with lower Stab2 expression and Stab2 KO mice displayed significantly lower PK than strains with higher Stab2 expression and the wild type (WT) animals respectively, confirming the role of Stab2 in regulating hepatic Malat1 ASO uptake. GWA examining ASO efficacy uncovered three loci associated with Malat1 potency: Small Subunit Processome Component (Utp11l) on chromosome 4, Rho associated coiled-coil containing protein kinase 2 (Rock2) and Aci-reductone dioxygenase (Adi1) on chromosome 12. Our results demonstrate the utility of mouse GWAS using the HMDP in detecting genes capable of impacting the uptake of ASOs, and identifies genes critical for the activity of ASOs in vivo.

Previous work in the clinic has clearly demonstrated differential patient response to antisense oligonucleotide (ASO) drugs. However, to date there has been no systematic evaluation of genes associated with this response in vivo. In this study, we utilized an advanced genetic methodology in mice to identify genes involved with the heterogeneity in both accumulation and potency of an ASO targeting metastasis associated lung adenocarcinoma transcript 1 (Malat1) in liver. Detailed analysis of ASO functionality in livers from 100 genetically distinct strains of inbred mice treated with either Malat1 or control ASO led to the selection of specific genetic regions associated with variation in ASO uptake and potency. Specifically, we identified regions on chromosomes 4 and 10 which highlighted two genes associated with variations in hepatic drug accumulation. Further, we established three regions on chromosome 4 and 12 linked to three genes associated with variability in hepatic ASO efficacy. We carried out additional functional validation of the isolated genes in mouse models and cell lines and confirmed that this methodology can be used to identify genes affecting ASO drug response. These results are particularly important for the design of antisense drugs with improved efficacy, safety, and tolerability.

Past, Present and Future of Therapeutic Interventions Targeting Leukocyte Trafficking in Inflammatory Bowel Disease

Studies in the 1990s using animal models of intestinal inflammation delineated the crucial molecules involved in leukocyte attraction and retention to the inflamed gut and associated lymphoid tissues. The first drug targeting leukocyte trafficking tested in inflammatory bowel diseases was the anti-ICAM-1 antisense oligonucleotide alicaforsen, showing only modest efficacy. Subsequently, the anti-α4 monoclonal antibody natalizumab proved efficacious for induction and maintenance of remission in Crohn's disease, but was associated with progressive multifocal leukoencephalopathy due to its ability to interfere with both α4β1 and α4β7 function. Later developments in this area took advantage of the fairly selective expression of MAdCAM-1 in the digestive organs, showing that vedolizumab, a more specific monoclonal antibody selectively blocking MAdCAM-1 binding to integrin α4β7, was efficacious for induction and maintenance of remission in ulcerative colitis and Crohn's disease, and it was not associated with neurological complications. Currently, other drugs targeting the β7 subunit, immunoglobulin superfamily molecules expressed on the endothelium, as well as blockade of lymphocyte recirculation in lymph nodes through modulation of sphingosine 1-phosphate receptors are under development. The potential use and risks of combined anti-trafficking therapy will be examined in this review.

Targeting Endothelial Ligands: ICAM-1/alicaforsen, MAdCAM-1

Specific blockade of the endothelial ligands intercellular adhesion molecule-1 [ICAM-1] and mucosal addressin cell adhesion molecule [MAdCAM] involved in leukocyte recruitment to the site of inflammation as therapeutic targets in inflammatory bowel disease [IBD] has been recognized from their overexpression in the inflamed mucosa and successful intervention based on these ligands in preclinical animal models. Interventions to target ICAM-1 in human IBD are confined to the ICAM-1 anti-sense oligonucleotide alicaforsen. While results with parenteral formulations of alicaforsen in Crohn's disease have largely been negative, efficacy signals derived from studies with an enema formulation in ulcerative colitis and pouchitis are promising and have led to a Food and Drug Administration Fast-Track designation for the latter. A large phase III programme in pouchitis is underway. Phase II studies with the anti-MAdCAM-1 antibody [SHP647] delivered positive results in ulcerative colitis and anti-inflammatory signals in Crohn's disease. Furthermore, it was shown that SHP647 does not affect the number and composition of cells in cerebrospinal fluid, suggesting that the compound is not affecting immune surveillance in the central nervous system. In addition, both alicaforsen and SHP647 are promising compounds based on the clear safety profile observed so far.

Inflammatory bowel disease: new therapies from antisense oligonucleotides

Inflammatory bowel diseases (IBD) are chronic inflammatory conditions of the gastrointestinal tract encompassing two main clinical entities: Crohn's disease (CD) and ulcerative colitis (UC). These disorders are characterized by various grades of tissue damage and development of local complications and extra-intestinal manifestations. The cause of IBD remains unknown but accumulating evidence indicates that both CD and UC arise in genetically predisposed individuals as a result of the action of multiple environmental factors, which ultimately trigger excessive and poorly controlled immune response against antigens of the luminal flora. Despite this realization, a full understanding of IBD pathogenesis is still out of reach and, consequently, treatment is far from optimal. However, in recent years, several pathways of intestinal damage have been delineated and the improved knowledge has contributed to the development of new therapies. Various approaches have been used to either inhibit the expression and/or function of inflammatory molecules or enhance counter-regulatory mechanisms. This review summarizes the available pre-clinical and clinical data for antisense oligonucleotides and oligonucleotide-based therapy to provide a comprehensive understanding of the rationale and mechanism of action of these compounds in IBD. Key messages Preclinical studies and clinical trials show that antisense oligonucleotide (ASO)-based therapy could be of benefit in inflammatory bowel diseases. ASOs have an excellent safety profile. Technical issues emerged from clinical trials suggest that changes in drug formulation and/or route of administration could improve ASO efficacy.

Systematic review with meta-analysis: endoscopic and histologic placebo rates in induction and maintenance trials of ulcerative colitis

BACKGROUND

Regulatory requirements for claims of mucosal healing in ulcerative colitis (UC) will require demonstration of both endoscopic and histologic healing. Quantifying these rates is essential for future drug development.

AIMS

To meta-analyse endoscopic and histologic placebo response and remission rates in UC randomised controlled trials (RCTs) and identify factors influencing these rates.

METHODS

MEDLINE, EMBASE and the Cochrane Library were searched from inception to March 2017 for placebo-controlled trials of pharmacological interventions for UC. Endoscopic and histologic placebo rates were pooled by random effects. Mixed effects univariable and multivariable meta-regression was used to evaluate the influence of patient, intervention and trial-related study-level covariates on these rates.

RESULTS

Fifty-six induction (placebo n = 4171) and 8 maintenance trials (placebo n = 1011) were included. Pooled placebo endoscopic remission and response rates for induction trials were 23% [95 confidence interval (CI) 19-28%] and 35% [95% CI 27-42%] respectively, and 20% [95% CI 16-24%] for maintenance of remission. The pooled histologic placebo remission rate was 14% [95% CI 8-22%] for induction trials. High heterogeneity was observed for all outcomes (I² 56.2%-88.3%). On multivariable meta-regression, central endoscopy reading was associated with significantly lower endoscopic placebo remission rates (16% vs 25%; OR = 0.52, [95% CI 0.29-0.92], P = 0.03). On univariable meta-regression, higher histologic placebo remission was associated with concomitant corticosteroids (OR = 1.17 [95% CI 1.08-1.26], P < 0.0001, per 10% increase in corticosteroid use).

CONCLUSIONS

Placebo endoscopic and histologic rates range from 14% to 35% in UC RCTs but are highly heterogeneous. Outcome standardisation may reduce heterogeneity and is needed in this field.

Heterogeneity in Definitions of Endpoints for Clinical Trials of Ulcerative Colitis: A Systematic Review for Development of a Core Outcome Set

BACKGROUND & AIMS

Advances in development of therapeutic agents for ulcerative colitis (UC) have been paralleled by innovations in trial design. It would be useful to identify a core outcome set, to standardize outcome definitions for efficacy and safety in clinical trials. We performed a systematic review of efficacy and safety outcomes reported in placebo-controlled randomized controlled trials of patients with UC.

METHODS

We searched MEDLINE, EMBASE, and the Cochrane Library from inception through March 1, 2017, for placebo-controlled randomized controlled trials of adult patients with UC treated with aminosalicylates, immunosuppressants, corticosteroids, biologics, and oral small molecules. We collected information on efficacy and safety outcomes, definitions, and measurement tools, stratified by decade of publication.

RESULTS

We analyzed data from 83 randomized controlled trials (68 induction and 15 maintenance) comprising 17,737 patients. Clinical or composite-clinical efficacy outcomes were reported in all trials; the UC Disease Activity Index and Mayo Clinic Score were frequently used to determine clinical response or remission. We found substantial variation in definitions of clinical or composite-clinical endpoints, with more than 50 definitions of response or remission. Endoscopic factors, histologic features, and fecal or serum biomarkers were used to determine outcomes in 83.1% (69 of 83), 24.1% (20 of 83), and 24.1% (20 of 83) of trials, respectively. A greater proportion of trials published after 2007 reported objective outcomes (96.5% endoscopic, 26.3% histologic, and 36.8% biomarker outcomes), but no standardized definitions of histologic or biomarker endpoints were found. Patient-reported efficacy and quality-of-life outcomes were described in 25 trials (30.1%) and safety outcomes were reported in 77 trials (92.8%).

CONCLUSION

In a systematic review, we found that despite recent advances in clinical trials methods, there is a great deal of variation in definitions of endpoints, including response and remission, in randomized controlled trials of patients with UC. Researchers should identify a core set of outcomes to standardize efficacy and safety reporting in UC clinical trials.

Alicaforsen, an Antisense Inhibitor of Intercellular Adhesion Molecule-1, in the Treatment for Left-Sided Ulcerative Colitis and Ulcerative Proctitis

BACKGROUND

Data on the efficacy of intercellular adhesion molecule-1 antisense oligonucleotide alicaforsen in ulcerative colitis (UC) is inconsistent.

METHODS

All patients, who had received at least one dose of alicaforsen, were analyzed retrospectively. Alicaforsen's efficacy was assessed in patients treated for left-sided UC and proctitis by comparing clinical and (if applicable) endoscopic disease activity before/after treatment.

RESULTS

Twelve patients were treated for left-sided UC or proctitis. Eleven patients received a 6-week course of a once-daily 240 mg alicaforsen enema formulation. In 1 patient, treatment was discontinued, because it was found to be inefficient. Disease activity measured by the partial Mayo score and 6-point symptom score was significantly reduced after treatment (6.0 vs. 2.4, p = 0.011 and 3.7 vs. 1.4, p = 0.008). Faecal calprotectin showed a trend towards reduction (484.4 vs. 179.5 μg/g, p = 0.063). Clinical improvement was achieved in 10 patients (83.3%). In 7 patients, a relapse occurred (70%). Median duration of clinical improvement was 18.0 weeks (range 1-112). Three patients showed an ongoing improvement of >9 months. No adverse events were reported.

CONCLUSIONS

A 6-week course of alicaforsen seemed to be safe and efficacious in inducing clinical improvement in patients with left-sided UC and proctitis. Prolonged clinical improvement was observed in many but not all patients.

Alicaforsen in the treatment of pouchitis

Alicaforsen is a 20-base antisense oligonucleotide inhibiting ICAM-1 production, which is an important adhesion molecule involved in leukocyte migration and trafficking to the site of inflammation. Hitherto, alicaforsen has been granted orphan drug designation and is prescribed as an unlicensed medicine in accordance with international regulation for the treatment of pouchitis and left-sided ulcerative colitis. Given the positive results evolving from one open-label trial and one case series in patients with chronic refractory pouchitis, US FDA has agreed to a rolling submission for a license application for the treatment of pouchitis, which has been recently initiated. Whether alicaforsen leads to higher endoscopic and clinical remission rates as placebo and whether the response can be maintained in the long-term in larger studies is yet unknown. An ongoing multicenter international Phase III trial will definitely address these unanswered questions.

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.

Alicaforsen for the treatment of inflammatory bowel disease

INTRODUCTION

Intracellular adhesion molecule-1 (ICAM-1), is a transmembrane glycoprotein of the immunoglobulin family, constitutively expressed on vascular endothelial cells and upregulated in inflamed colonic tissue. Alicaforsen, a 20 base ICAM-1 anti-sense oligonucleotide and highly selective ICAM-1 inhibitor, down-regulates ICAM-1 mRNA. Areas covered: We review mechanism of action, pharmacokinetics, pre-clinical, clinical and safety data of alicaforsen for the treatment of ulcerative colitis (UC), pouchitis and Crohn's disease (CD). Expert opinion: After 6 weeks of treatment, topical alicaforsen was significantly more effective than placebo in inducing remission in patients with moderate-severe distal UC, with treatment effects lasting up to 30 weeks. No difference was observed in head-head comparison with mesalamine topical enema, although alicaforsen appeared to have more durable treatment effect. Clinical trials of an intravenous formulation in Crohn's disease showed no significant treatment effect compared to placebo. An open-label trial in alicaforsen for pouchitis demonstrated encouraging results, now being assessed in a multi-national phase 3 trial. No major safety signals have been observed in UC patients treated with alicaforsen enemas. The potential as a novel therapy for pouchitis has led to orphan designation for this indication by the FDA and European Medicines Agency.

Antisense molecules: A new class of drugs

An improved understanding of disease pathogenesis leads to identification of novel therapeutic targets. From a pharmacologic point of view, these can be addressed by small chemical compounds, so-called biologicals (eg, mAbs and recombinant proteins), or by a rather new class of molecule based on the antisense concept. Recently, a new wave of clinical studies exploring antisense strategies is evolving. In addition to cancer, they include predominantly trials on infectious and noninfectious diseases, such as chronic inflammatory and metabolic conditions. This article, based on a systematic PubMed literature search, highlights recent developments in this emerging field.

Genetic risk variants as therapeutic targets for Crohn's disease

INTRODUCTION

The pathogenesis of Inflammatory bowel diseases (IBD) is multifactorial, with interactions between genetic and environmental factors. Despite the existence of genetic factors being largely demonstrated by epidemiological data and several genetic studies, only a few findings have been useful in term of disease prediction, disease progression and targeting therapy. Areas covered: This review summarizes the results of genome-wide association studies in Crohn's disease, the role of epigenetics and the recent discovery by genetic studies of new pathogenetic pathways. Furthermore, it focuses on the importance of applying genetic data to clinical practice, and more specifically how to better target therapy and predict potential drug-related toxicity. Expert opinion: Some genetic markers identified in Crohn`s disease have allowed investigators to hypothesize about, and in some cases, prove the usefulness of new specific therapeutic agents. However, the heterogeneity and complexity of this disease has so far limited the daily clinical use of genetic information. Finally, the study of the implications of genetics on therapy, either to predict efficacy or avoid toxicity, is considered still to be in its infancy.

Pharmacology of Antisense Drugs

Recent studies have led to a greater appreciation of the diverse roles RNAs play in maintaining normal cellular function and how they contribute to disease pathology, broadening the number of potential therapeutic targets. Antisense oligonucleotides are the most direct means to target RNA in a selective manner and have become an established platform technology for drug discovery. There are multiple molecular mechanisms by which antisense oligonucleotides can be used to modulate RNAs in cells, including promoting the degradation of the targeted RNA or modulating RNA function without degradation. Antisense drugs utilizing various antisense mechanisms are demonstrating therapeutic potential for the treatment of a broad variety of diseases. This review focuses on some of the advances that have taken place in translating antisense technology from the bench to the clinic.

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.

Antisense approach to inflammatory bowel disease: prospects and challenges

Despite the great success of anti-tumour necrosis factor-based therapies, the treatment of Crohn's disease (CD) and ulcerative colitis (UC) still remains a challenge for clinicians, as these drugs are not effective in all patients, their efficacy may wane with time, and their use can increase the risk of adverse events and be associated with the development of new immune-mediated diseases. Therefore, new therapeutic targets are currently being investigated both in pre-clinical studies and in clinical trials. Among the technologies used to build new therapeutic compounds, the antisense oligonucleotide (ASO) approach is slowly gaining space in the field of inflammatory bowel diseases (IBDs), and three ASOs have been investigated in clinical trials. Systemic administration of alicaforsen targeting intercellular adhesion molecule-1, a protein involved in the recruitment of leukocytes to inflamed intestine, was not effective in CD, even though the same compound was of benefit when given as an enema to UC patients. DIMS0150, targeting nuclear factor (NF) κB-p65, a transcription factor that promotes pro-inflammatory responses, was very promising in pre-clinical studies and is currently being tested in clinical trials. Oral mongersen, targeting Smad7, an intracellular protein that inhibits transforming growth factor (TGF)-β1 activity, was safe and well tolerated by CD patients, and the results of a phase II clinical trial showed the efficacy of the drug in inducing clinical remission in patients with active disease. In this leading article, we review the rationale and the clinical data available regarding these three agents, and we discuss the challenge of using ASOs in IBD.

Treatment and prevention of pouchitis after ileal pouch-anal anastomosis for chronic ulcerative colitis

BACKGROUND

Pouchitis occurs in approximately 50% of patients following ileal pouch-anal anastomosis (IPAA) for chronic ulcerative colitis.

OBJECTIVES

The primary objective was to determine the efficacy and safety of medical therapies (including antibiotics, probiotics, and other agents) for prevention or treatment of acute or chronic pouchitis.

SEARCH METHODS

We searched MEDLINE, EMBASE and the Cochrane Library from inception to October 2014.

SELECTION CRITERIA

Randomized controlled trials of prevention or treatment of acute or chronic pouchitis in adults who underwent IPAA for ulcerative colitis were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently screened studies for eligibility, extracted data and assessed study quality. Methodological quality was assessed using the Cochrane risk of bias tool. The overall quality of the evidence supporting the outcomes was evaluated using the GRADE criteria. The primary outcome was the proportion of patients with clinical improvement or remission of pouchitis in patients with acute or chronic pouchitis, or the proportion of patients with no episodes of pouchitis after IPAA. The proportion of patients who developed at least one adverse event was a secondary outcome. We calculated the risk ratio (RR) and corresponding 95% confidence interval (CI) for each dichotomous outcome.

MAIN RESULTS

Thirteen studies (517 participants) were included in the review. Four studies assessed treatment of acute pouchitis. One study (16 participants) compared ciprofloxacin and metronidazole; another (26 participants) compared metronidazole to budesonide enemas; another (18 participants) compared rifaximin to placebo; and the fourth study (20 participants) compared Lactobacillus GG to placebo. Four studies assessed treatment of chronic pouchitis. One study (19 participants) compared glutamine to butyrate suppositories; another (40 participants) compared bismuth enemas to placebo; and two studies (76 participants) compared VSL#3 to placebo. Five studies assessed prevention of pouchitis. One study (40 participants) compared VSL#3 to placebo; another (28 participants) compared VLS#3 to no treatment; one study (184 participants) compared allopurinol to placebo; another (12 participants) compared the probiotic Bifidobacterium longum to placebo; and one study (38 participants) compared tinidazole to placebo. Three studies were judged to be of high quality. Two studies were judged to be low quality and the quality of the other studies was unclear. Treatment of acute pouchitis: The results of one small study (16 participants) suggest that ciprofloxacin may be more effective than metronidazole for the treatment of acute pouchitis. One hundred per cent (7/7) of ciprofloxacin patients achieved remission at two weeks compared to 33% (3/9) of metronidazole patients. A GRADE analysis indicated that the overall quality of the evidence supporting this outcome was very low due to high risk of bias (no blinding) and very sparse data (10 events). There was no difference in the proportion of patients who had at least one adverse event (RR 0.18, 95% CI 0.01 to 2.98). Adverse events included vomiting, dysgeusia or transient peripheral neuropathy. There were no differences between metronidazole and budesonide enemas in terms of clinical remission, clinical improvement or adverse events. Adverse events included anorexia, nausea, headache, asthenia, metallic taste, vomiting, paraesthesia, and depression. There were no differences between rifaximin and placebo in terms of clinical remission, clinical improvement, or adverse events. Adverse events included diarrhea, flatulence, nausea, proctalgia, vomiting, thirst, candida, upper respiratory tract infection, increased hepatic enzyme, and cluster headache. There was no difference in clinical improvement between Lactobacillus GG and placebo. The results of these studies are uncertain due to very low quality evidence. Treatment of chronic pouchitis: A pooled analysis of two studies (76 participants) suggests that VSL#3 may be more effective than placebo for maintenance of remission. Eighty-five per cent (34/40) of VLS#3 patients maintained remission at 9 to 12 months compared to 3% (1/36) of placebo patients (RR 20.24, 95% CI 4.28 to 95.81). A GRADE analysis indicated that the quality of evidence supporting this outcome was low due to very sparse data (35 events). Adverse events included abdominal cramps, vomiting and diarrhea. There was no difference in effectiveness between glutamine and butyrate suppositories for maintenance of remission. There was no difference in clinical improvement or adverse event rates between bismuth carbomer foam enemas and placebo. Adverse events included diarrhea, worsening symptoms, cramping, sinusitis, and abdominal pain. The results of these studies are uncertain due to very low quality evidence. Prevention of pouchitis: The results of one small study (40 participants) suggest that VSL#3 may be more effective than placebo for prevention of pouchitis. Ninety per cent (18/20) of VSL#3 patients had no episodes of acute pouchitis during the 12 month study compared to 60% (12/20) of placebo patients (RR 1.50, 95% CI 1.02 to 2.21). A GRADE analysis indicated that the quality of evidence supporting this outcome was low due to very sparse data (30 events). Another small study (28 participants) found that VLS#3 was not more effective than no treatment for prevention of pouchitis. Bifidobacterium longum, allopurinol and tinidazole were not more effective than placebo for prevention of pouchitis. The results of these studies are uncertain due to very low quality evidence.

AUTHORS' CONCLUSIONS

For acute pouchitis, very low quality evidence suggests that ciprofloxacin may be more effective than metronidazole. For chronic pouchitis, low quality evidence suggests that VSL#3 may be more effective than placebo for maintenance of remission. For the prevention of pouchitis, low quality evidence suggests that VSL#3 may be more effective than placebo. Well designed, adequately powered studies are needed to determine the optimal therapy for the treatment and prevention of pouchitis.

Therapeutic innovations in inflammatory bowel diseases

Inflammatory bowel disease (IBD) is a spectrum of complex multifactorial immune disorders characterized by chronic inflammation of the gut. Significant advances have been made in unraveling the pathogenesis of this disease spectrum, which have spurred the discovery of new therapeutic targets and strategies. In this review, we highlight the emerging new classes of IBD therapeutics under clinical evaluation and their method of action, including JAK inhibitors, anti-SMAD7 oligonucleotides, and cell-based therapies. Moreover, we discuss how an approach based on unique molecular insights in a given patient will, in the future, lead to a truly individualized/tailored disease management, starting at diagnosis, aiding in prognosis, and resulting in a personalized therapeutic approach.

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.

Alicaforsen, an antisense inhibitor of ICAM-1, as treatment for chronic refractory pouchitis after proctocolectomy: A case series

BACKGROUND AND AIMS

The published data about the efficacy of the intercellular adhesion molecule-1 (ICAM-1) antisense oligonucleotide termed alicaforsen in inflammatory bowel disease (IBD) is rather inconsistent. This case series analyzes its efficacy in chronic refractory pouchitis, after proctocolectomy.

METHODS

We performed a retrospective analysis on all patients who had received at least one dose of alicaforsen for IBD at three referral centers in Switzerland. We assessed the drug's efficacy in patients treated for chronic refractory pouchitis, by comparing the clinical and/or endoscopic disease activity at baseline with a 2-3-month follow-up visit.

RESULTS

We identified 22 patients who had received at least one dose. Among them, 13 patients were being treated for chronic refractory pouchitis. These patients had a median age of 38.0 years (95% CI 21.0-69.0) and five were female (38.5%). The median time since pouch surgery was 102.5 months (95% CI 16.0-288.0), with a median pouchitis duration of 16.0 months (95% CI 4.0-216.0). At 2-3 months after therapy, clinical and endoscopic disease activity was significantly reduced (stool frequency 9.0 versus 6.0, the Pouchitis Disease Activity Index (PDAI) clinical subscore was 4.0 versus 1.0, and the endoscopic disease activity was 4.0 versus 2.0). Clinical improvement was achieved in 11 out of 13 pouchitis patients (84.6%); however, a relapse was observed in nine of these patients (81.8%). The median time from clinical improvement to relapse was 16 weeks (95% CI 9.0-23.0).

CONCLUSIONS

Alicaforsen seemed to be efficacious in inducing clinical and/or endoscopic improvement in chronic refractory pouchitis and may be a promising treatment alternative in those patients; however, given the high proportion of relapse, one 6-week course of alicaforsen may not be sufficient.

Systematic Review: Rectal Therapies for the Treatment of Distal Forms of Ulcerative Colitis

BACKGROUND

Many therapeutic options are available for patients with distal forms of ulcerative colitis (UC). Rectal therapies (e.g., suppositories, foams, gels, and enemas) may be recommended either alone or in combination with oral treatment. Compared with oral therapies, rectal therapies are underused in patients with distal forms of UC, although rectal therapies have favorable efficacy and safety profiles.

METHODS

This systematic review identified 48 articles for inclusion after a comprehensive PubMed search and the identification of additional relevant articles through other sources. Inclusion criteria were clinical studies examining efficacy and safety of 5-aminosalicylic acid, corticosteroid, and non-5-aminosalicylic acid rectal therapies (suppositories, foams, gels, and enemas) that induce or maintain remission in patients with ulcerative proctitis, ulcerative proctosigmoiditis, or left-sided colitis (i.e., distal forms of UC). The quality of the evidence presented was evaluated using the GRADE system.

RESULTS

Overall, a greater percentage of patients with distal forms of UC receiving 5-aminosalicylic acids or corticosteroid rectal formulations derived greater therapeutic benefit after treatment compared with patients receiving placebo. Furthermore, most uncontrolled studies of rectal therapies reported that patients with distal forms of UC had marked improvement from baseline after treatment. The overall safety profile of rectal therapies was favorable. Treatment with second-generation corticosteroids, such as budesonide and beclomethasone dipropionate, did not increase the incidence of steroid-related adverse effects.

CONCLUSIONS

The current literature supports the use of rectal therapies for both induction and maintenance of remission in patients with distal forms of UC.

Targeting leukocyte trafficking for the treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic immune-mediated inflammatory disease of the intestine that includes both Crohn's disease and ulcerative colitis, and afflicts nearly 1 million people throughout North America. As our understanding of IBD pathogenesis grows, several new therapies have been developed that use monoclonal antibodies to specifically target key mediators and biological pathways implicated in IBD immune dysfunction. One important pathway involves leukocyte trafficking and infiltration into the affected intestinal tissues. This review provides a summary of the different therapies that have been developed to inhibit leukocyte trafficking to the inflamed gut, and evaluates the relative safety and efficacy of these novel drugs within the context of existing medical therapies for IBD.

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.

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.

Alicaforsen: An Emerging Therapeutic Agent for Ulcerative Colitis and Refractory Pouchitis

Pouchitis is a relatively common complication that develops following ileal pouch-anal anastomosis in patients with complicated ulcerative colitis (UC). Both pouchitis and UC share similarities in their development, as well as in the mechanisms involving mediators of the inflammatory process. In the recent years, the discovery and investigation of biological therapies have led to advancement in the management of these disorders, and the continuation of research on this novel area holds strong implications for a future reduction in the use of invasive surgical procedures. Alicaforsen represents one of these emerging therapeutic agents, and has demonstrated promising results in both preclinical and clinical settings. This article reviews the therapeutic effects of alicaforsen for the management of UC and refractory pouchitis, with special emphasis on the mechanism of action of this therapeutic agent and the clinical studies asserting its effectiveness.

Propionyl-L-Carnitine is Efficacious in Ulcerative Colitis Through its Action on the Immune Function and Microvasculature

Objectives:

Microvascular endothelial dysfunction characterizes ulcerative colitis (UC), the most widespread form of inflammatory bowel disease. Intestinal mucosal microvessels in UC display aberrant expression of cell adhesion molecules (CAMs) and increased inflammatory cell recruitment. Propionyl-L-carnitine (PLC), an ester of L-carnitine required for the mitochondrial transport of fatty acids, ameliorates propionyl-CoA bioavailability and reduces oxidative stress in ischemic tissues. The present study aimed to document the efficacy of anti-oxidative stress properties of PLC in counteracting intestinal microvascular endothelial dysfunction and inflammation.

Methods:

To evaluate the efficacy in vivo, we analyzed the effects in intestinal biopsies of patients with mild-to-moderate UC receiving oral PLC co-treatment and in rat TNBS-induced colitis; in addition, we investigated antioxidant PLC action in TNF-α-stimulated human intestinal microvascular endothelial cells (HIMECs) in vitro.

Results:

Four-week PLC co-treatment reduced intestinal mucosal polymorph infiltration and CD4⁺ lymphocytes, ICAM-1⁺ and iNOS⁺ microvessels compared with placebo-treated patients with UC. Oral and intrarectal administration of PLC but not L-carnitine or propionate reduced intestinal damage and microvascular dysfunction in rat TNBS-induced acute and reactivated colitis. In cultured TNF-α-stimulated HIMECs, PLC restored β-oxidation and counteracted NADPH oxidase 4-generated oxidative stress-induced CAM expression and leukocyte adhesion. Inhibition of β-oxidation by L-aminocarnitine increased reactive oxygen species production and PLC beneficial effects on endothelial dysfunction and leukocyte adhesion. Finally, PLC reduced iNOS activity and nitric oxide accumulation in rat TNBS-induced colitis and in HIMEC cultures.

Conclusions:

Our results show that the beneficial antioxidant effect of PLC targeting intestinal microvasculature restores endothelial β-oxidation and function, and reduces mucosal inflammation in UC patients.

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.