Safety and efficacy of two dose formulations of alicaforsen enema compared with mesalazine enema for treatment of mild to moderate left-sided ulcerative colitis: a randomized, double-blind, active-controlled trial

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.

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.

Controlling in and out - the future of interfering with immune cell trafficking in inflammatory bowel disease

INTRODUCTION

Immune cell trafficking is a key requirement in the pathogenesis of inflammatory bowel diseases. Consistently, therapeutic strategies to target immune cell trafficking have been established and continue to be developed for the treatment of ulcerative colitis and Crohn's disease.

AREAS COVERED

In this review, we briefly summarize the most important checkpoints of intestinal immune cell trafficking and their importance during IBD. Moreover, we provide an overview of associated therapeutic targets and previous as well as current efforts on treatment strategies related to these targets.

EXPERT OPINION

Finally, we comment on potential future developments that might shape the field of immune cell trafficking in the context of IBD.

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.

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.

miRNA-Based Potential Biomarkers and New Molecular Insights in Ulcerative Colitis

Ulcerative colitis (UC) is a chronic non-specific inflammatory bowel disease, which usually manifests as abdominal pain, diarrhea and hematochezia. The disease often recurs and is difficult to cure. At present, the pathogenesis is not clear, but it is believed that the disease is caused by a complex interaction among immunity, heredity, environment and intestinal microflora disorders. MicroRNA (miRNA) is endogenous single-stranded non-coding RNA of 17–25 nucleotides (nts). They target the 3'Untranslated Region of a target gene and inhibit or degrade the target gene according to the extent of complementary bases. As important gene expression regulators, miRNAs are involved in regulating the expression of most human genes, and play an important role in the pathogenesis of many autoimmune diseases including UC. Studies in recent years have illustrated that abnormal expression of miRNA occurs very early in disease pathogenesis. Moreover, this abnormal expression is highly related to disease activity of UC and colitis-associated cancer, and involves virtually all key UC-related mechanisms, such as immunity and intestinal microbiota dysregulation. Recently, it was discovered that miRNA is highly stable outside the cell in the form of microvesicles, exosomes or apoptotic vesicles, which raises the possibility that miRNA may serve as a novel diagnostic marker for UC. In this review, we summarize the biosynthetic pathway and the function of miRNA, and summarize the usefulness of miRNA for diagnosis, monitoring and prognosis of UC. Then, we described four types of miRNAs involved in regulating the mechanisms of UC occurrence and development: 1) miRNAs are involved in regulating immune cells; 2) affect the intestinal epithelial cells barrier; 3) regulate the homeostasis between gut microbiota and the host; and 4) participate in the formation of tumor in UC. Altogether, we aim to emphasize the close relationship between miRNA and UC as well as to propose that the field has value for developing potential biomarkers as well as therapeutic targets for UC.

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 technology: A review

Antisense technology is beginning to deliver on the broad promise of the technology. Ten RNA-targeted drugs including eight single-strand antisense drugs (ASOs) and two double-strand ASOs (siRNAs) have now been approved for commercial use, and the ASOs in phase 2/3 trials are innovative, delivered by multiple routes of administration and focused on both rare and common diseases. In fact, two ASOs are used in cardiovascular outcome studies and several others in very large trials. Interest in the technology continues to grow, and the field has been subject to a significant number of reviews. In this review, we focus on the molecular events that result in the effects observed and use recent clinical results involving several different ASOs to exemplify specific molecular mechanisms and specific issues. We conclude with the prospective on the technology.

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.

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.

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.

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.

Old and New Lymphocyte Players in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), encompassing Crohn's disease and ulcerative colitis, is a chronic intestinal inflammatory disorder characterized by diffuse accumulation of lymphocytes in the gut mucosa as a consequence of over-expression of endothelial adhesion molecules. The infiltrating lymphocytes have been identified as subsets of T cells, including T helper (Th)1 cells, Th17 cells, and regulatory T cells. The function of these lymphocyte subpopulations in the development of IBD is well-known, since they produce a number of pro-inflammatory cytokines, such as interferon-γ and interleukin-17A, which in turn activate mucosal proteases, thus leading to the development of intestinal lesions, i.e., ulcers, fistulas, abscesses, and strictures. However, the immune mechanisms underlying IBD are not yet fully understood, and knowledge about the function of newly discovered lymphocytes, including Th9 cells, innate lymphoid cells, mucosal-associated invariant T cells, and natural killer T cells, might add new pieces to the complex puzzle of IBD pathogenesis. This review summarizes the recent advances in the understanding of the role of mucosal lymphocytes in chronic intestinal inflammation and deals with the therapeutic potential of lymphocyte-targeting drugs in IBD patients.

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.

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.

Current and Future Targets for Mucosal Healing in Inflammatory Bowel Disease

The induction and subsequent maintenance of mucosal healing has emerged as one of the central therapeutic goals in the management of patients with inflammatory bowel disease (IBD) (Crohn's disease and ulcerative colitis). Current and novel treatment options are assessed regarding their therapeutic efficacy on the basis of their ability to induce mucosal healing. However, there is still substantial debate about the precise definition of mucosal healing. Here, we will give an overview regarding the definitions of mucosal healing as well as its probable effects on long-term disease behavior and finally focus on current and potential therapeutic targets to achieve this therapeutic goal in IBD patients.

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.

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.

Bioengineering of noncoding RNAs for research agents and therapeutics

The discovery of functional small noncoding RNAs (ncRNAs), such as microRNAs and small interfering RNAs, in the control of human cellular processes has opened new avenues to develop RNA-based therapies for various diseases including viral infections and cancers. However, studying ncRNA functions and developing RNA-based therapeutics relies on access to large quantities of affordable ncRNA agents. Currently, synthetic RNAs account for the major source of agents for RNA research and development, yet carry artificial modifications on the ribose ring and phosphate backbone in sharp contrast to posttranscriptional modifications present on the nucleobases or unmodified natural RNA molecules produced within cells. Therefore, large efforts have been made in recent years to develop recombinant RNA techniques to cost-effectively produce biological RNA agents that may better capture the structure, function, and safety properties of natural RNAs. In this article, we summarize and compare current in vitro and in vivo methods for the production of RNA agents including chemical synthesis, in vitro transcription, and bioengineering approaches. We highlight the latest recombinant RNA approaches using transfer RNA (tRNA), ribosomal RNA (rRNA), and optimal ncRNA scaffold (OnRS), and discuss the applications of bioengineered ncRNA agents (BERAs) that should facilitate RNA research and development.

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.

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.

Prospects for Therapeutic Targeting of MicroRNAs in Human Immunological Diseases

MicroRNAs (miRNAs) are endogenous oligoribonucleotides with exciting therapeutic potential. Early studies established a clear role for miRNAs in leukocyte biology. The first miRNA-based therapy, miravirsen, is now in phase 2 clinical trials, making the reality of these therapies undeniable. The capacity for miRNAs to fine-tune inflammatory signaling make them attractive treatment targets for immunological diseases. Nonetheless, the degree of redundancy among miRNAs, coupled with the promiscuity of miRNA binding sites in the transcriptome, require consideration when designing miRNA-directed interventions. Altered miRNA expression occurs across a range of inflammatory conditions, including inflammatory bowel disease, arthritis, and diabetes. However, very few studies successfully treated murine models of immunological diseases with miRNA-based approaches. While discussing recent studies targeting miRNAs to treat immunological conditions, we also reflect on the risks of miRNA targeting and showcase some newer delivery systems that may improve the pharmacological profile of this class of therapeutics.

MicroRNAs in inflammatory bowel diseases: paradoxes and possibilities

MicroRNAs (miRNAs) are single-stranded RNA molecules, which influence the translation of messenger RNA and hence protein synthesis. The altered expression of miRNAs in disease states in cancer and autoimmune diseases including inflammatory bowel disease is providing new insights into disease pathogenesis. This understanding is leading to consideration of the utility of miRNAs in diagnostics, prognostics, and therapeutics in inflammatory bowel disease. A literature search was conducted using the MEDLINE/PubMed databases using search terms inflammatory bowel disease, miRNA, treatment, and biomarkers.

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.

Translational research and efficacy of biologics in Crohn's disease: a cautionary tale

In the last several years many biologic agents for Crohn's disease have been developed. Due to their unique molecular specificity biologics are de facto indicators of the ultimate significance of the molecule targeted by the biologic itself. Here, we have reviewed many clinical studies that have used biologics for Crohn's disease. Their results show that despite potentially sound theoretical mechanisms of action and some initially promising data, most biologics - with few notable exceptions - have failed. Pharmacologic, study design or patient-related issues might explain these findings in some studies. However in many cases clinical failure of biologics might highlight the complexity of in vivo events and the potential deficiencies of current experimental settings. Hence, these observations call for new and efficient ways of predicting drug efficacy in clinical trials based on bench research. Conceivably, computer-based pathogenetic models could be used to simulate and predict clinical studies results in vivo.

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.

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.

Antisense oligonucleotides on neurobehavior, respiratory, and cardiovascular function, and hERG channel current studies

INTRODUCTION

Safety Pharmacology studies were conducted in mouse, rat, and non-human primate to determine in vivo effects of antisense oligonucleotides (ASOs) on the central nervous system, respiratory system, and cardiovascular system. Effects on the hERG potassium channel current was evaluated in vitro.

METHODS

ASOs contained terminal 2'-O-methoxyethyl nucleotides, central deoxy nucleotides, and a phosphorothioate backbone. Neurobehavior was evaluated by Functional Observatory Battery in rodents. Respiratory function was directly measured in rodents by plethysmograph; respiratory rate and blood gases were measured in monkey. Basic cardiovascular endpoints were measured in rat; cardiovascular evaluation in monkey involved implanted telemetry units. In single and repeat dose studies ASOs were administered by subcutaneous injection at up to 300 mg/kg, 250 mg/kg, and 40 mg/kg in mouse, rat, or monkey, respectively. Assays were performed in HEK293 or CHO-K1 cells, stably transfected with hERG cDNA, at ASO concentrations of up to 300 μM.

RESULTS

No apparent effects were noted for respiratory or CNS function. Continuous monitoring of the cardiovascular system in monkey demonstrated no ASO-related changes in blood pressures, heart rate, or ECG and associated parameters (i.e., QRS duration). Specific assessment of the hERG potassium channel indicated no potential for actions on ventricular repolarization or modest effects only at excessive concentrations.

DISCUSSION

The absence of direct actions on neurobehavior and respiratory function associated with the administration of ASOs in safety pharmacology core battery studies is consistent with published toxicology studies. The combination of in vitro hERG studies and in vivo studies in rat and monkey are consistent with no direct actions by ASOs on cardiac cell function or electrical conduction at relevant concentrations and dose levels. Taken as a whole, dedicated studies focused on the safety pharmacology of specific organ systems do not appear to add significant data for interpretation of potential adverse effects. The need for dedicated studies for future ASOs in the same class is questionable, as a more encompassing data set can be collected in repeat dose and longer-term toxicology studies.

Meta-analysis using individual patient data: efficacy and durability of topical alicaforsen for the treatment of active ulcerative colitis

BACKGROUND

The antisense ICAM-1 inhibitor alicaforsen has been studied in four phase 2 studies in ulcerative colitis (UC). Recruited patients varied as to the extent of their colitis and in the severity of disease at entry.

AIM

To investigate the efficacy of alicaforsen enema in specific UC populations. Efficacy was analysed for short-term (week 6-10) and long-term (week 30) outcomes compared with either placebo or a high-dose mesalazine (mesalamine) enema in patients with disease extent up to 40 cm from the anal verge in patients with moderate or severe disease, and in patients with both of these features.

METHODS

Individual patient data meta-analyses of 200 patients from four phase 2 studies evaluating nightly alicaforsen 240 mg enema and comparators. Patient data were pooled and analysed in a single data set. Continuous outcomes were evaluated using anova; dichotomous outcomes were evaluated using Pearson chi-square or Fisher's exact tests.

RESULTS

Alicaforsen showed superior efficacy vs. placebo in: patients with disease extent up to 40 cm, patients with moderate and severe disease and especially when both those conditions were satisfied. In these patient groups, mesalazine also showed short-term efficacy. At week 30, however, the efficacy of mesalazine waned and alicaforsen became significantly more efficacious.

CONCLUSIONS

This post hoc meta-analysis showed that alicaforsen is effective in patients with active UC, especially in patients with distal disease, which is of moderate/severe activity. The efficacy of alicaforsen was durable in these sub-groups, suggesting a disease-modifying effect. This analysis suggests that alicaforsen enema may offer an effective, potentially durable response in moderate/severe distal active UC.

High mucosal healing rates in 5-ASA-treated ulcerative colitis patients: results of a meta-analysis of clinical trials

BACKGROUND

Recently, mucosal healing (MH) is regarded as an important treatment goal in ulcerative colitis (UC). 5-Aminosalicylates (5-ASA) are the standard treatment in mild-to-moderate UC, but the effect on MH is less known. The aim of this study was to systematically review the medical literature in order to compare different preparations of 5-ASA for the effect on MH.

METHODS

We conducted a structured search of PubMed and the Cochrane Central Register of Controlled Trials to identify randomized controlled clinical trials with 5-ASA in UC providing data about MH. We calculated the sample size-weighted pooled proportion of patients with MH, and performed meta-analysis of head-to-head comparisons.

RESULTS

Out of 645 hits, we included 90 treatment arms, involving 3977 patients using oral 5-ASA (granulate and tablets) and 2513 patients using rectal 5-ASA (suppositories, enema, and foam). Overall, 43,7% of 5-ASA treated patients achieved MH (oral 36,9%; rectal 50,3%). In oral studies, 49% of patients using granulate (7 treatment-arms) achieved MH compared to 34,9% using tablets (43 treatment-arms). In rectal studies the proportion of MH was 62% for suppositories (eight treatment arms), 51% for foam (nine treatment arms), and 46% for enema (23 treatment arms), respectively.

CONCLUSIONS

5-ASA preparations achieved MH in nearly 50% of UC patients. There were no significant differences in MH between the various 5-ASA agents, either in the oral or the rectal treatment groups.

Etiology of pouchitis

Restorative proctocolectomy with ileal-pouch anal anastomosis (RPC) is the operation of choice for ulcerative colitis (UC) patients requiring surgery. It is also used for patients with familial adenomatous polyposis (FAP). Pouchitis accounts for 10% of pouch failures. It is an idiopathic inflammatory condition that may occur in up to 50% of patients after RPC for UC. It is rarely seen in FAP patients after RPC. The etiology of pouchitis remains unclear. An overlap with UC is suggested by the frequency with which pouchitis affects patients with UC compared with FAP patients. There is significant clinical evidence implicating bacteria in the pathogenesis of pouchitis. Studies using culture and molecular methods demonstrate a dysbiosis of the pouch microbiota in pouchitis. Risk factors, genetic associations, and serological markers of pouchitis suggest that the interactions between the host immune responses and the pouch microbiota underlie the etiology of this idiopathic inflammatory condition. Here we present a detailed review of the data focusing on the pouch microbiota and the immune responses that support this hypothesis. We also discuss the contribution of luminal metabolic factors and the epithelial membrane in the etiology of this inflammatory process. The ileoanal pouch offers a unique opportunity to study the inter-relationships between the gut microbiota and host immune responses from before the onset of disease. For this reason the study of pouchitis could serve as a human model that significantly enhances our understanding of inflammatory bowel diseases in general.

Targeting leukocyte migration and adhesion in Crohn's disease and ulcerative colitis

Crohn's disease and ulcerative colitis are two chronic inflammatory bowel diseases. Current biologic therapies are limited to blocking tumor necrosis factor alpha. However, some patients are primary non-responders, experience a loss of response, intolerance or side effects defining the urgent unmet need for novel treatments. The rapid recruitment and inappropriate retention of leukocytes is a hallmark of chronic inflammation and a potentially promising therapeutic target. We discuss the immunological mechanisms of leukocyte homing and adhesion in the gut mucosa. The interaction of lymphocytes (CD4+ T-cells, CD8+ T-cells, T(REG), T(H)1, T(H)17, B-cells), monocytes, macrophages, dendritic cells and granulocytes with endothelial and epithelial cells through integrins [α4β7 (LPAM-1), α(E)β₇ (HML1 Human Mucosal Lymphocyte Antigen 1), α₄β₁ (VLA-4), α(L)β₇, (LFA-1)] and their ligands immunoglobulin superfamily cellular adhesion molecules (CAM) (MAdCAM-1 Mucosal Addressin Cellular Adhesion Molecule 1, ICAM-1 Intercellular Cell Adhesion Molecule, VCAM-1 Vascular Cell Adhesion Molecule), fibronectin as well as chemokine receptors (CCR2, CCR4, CCR5, CCR7, CCR9, CCR10, CXCR3, CX3CR1) and chemokines [CCL5, CCL25 (TECK Thymus Expressed Chemokine), CCL28, CX3CL1, CXCL10, CXCL12] in the process of gut homing is critically reviewed and summarized in scientific cartoons. Moreover, we discuss the clinical trial results of approved and investigational antibodies and small molecules including natalizumab (anti-α₄ Tysabri®, Antegren®), AJM300 (anti-α4), etrolizumab (anti-β7, rhuMAb-Beta7), vedolizumab (anti-α4β7, LDP-02, MLN-02, MLN0002), PF-00547659 (anti-MAdCAM), Alicaforsen (anti-ICAM-1), and CCX282-B (anti-CCR9, GSK-1605786, Traficet-EN™) and their risks such as PML reported for natalizumab. Hopefully, the newer gut specific drug designs discussed in this article will have an impact on both efficacy and safety.