Impact of patient characteristics on the clinical efficacy of mongersen (GED-0301), an oral Smad7 antisense oligonucleotide, in active Crohn's disease

Emerging strategy towards mucosal healing in inflammatory bowel disease: what the future holds?

For decades, the therapeutic goal of conventional treatment among inflammatory bowel disease (IBD) patients is alleviating exacerbations in acute phase, maintaining remission, reducing recurrence, preventing complications, and increasing quality of life. However, the persistent mucosal/submucosal inflammation tends to cause irreversible changes in the intestinal structure, which can barely be redressed by conventional treatment. In the late 1990s, monoclonal biologics, mainly anti-TNF (tumor necrosis factor) drugs, were proven significantly helpful in inhibiting mucosal inflammation and improving prognosis in clinical trials. Meanwhile, mucosal healing (MH), as a key endoscopic and histological measurement closely associated with the severity of symptoms, has been proposed as primary outcome measures. With deeper comprehension of the mucosal microenvironment, stem cell niche, and underlying mucosal repair mechanisms, diverse potential strategies apart from monoclonal antibodies have been arising or undergoing clinical trials. Herein, we elucidate key steps or targets during the course of MH and review some promising treatment strategies capable of promoting MH in IBD.

Breaking through the therapeutic ceiling of inflammatory bowel disease: Dual-targeted therapies

Emerging biologics and small-molecule drugs have changed the clinical status quo of inflammatory bowel disease (IBD). However, current treatments remain at a standstill in terms of response and remission in many cases. Accumulating evidence indicates that dual-targeted therapy (DTT) could be promising in overcoming the existing ceiling of IBD treatment. However, data on the efficacy and safety of DTT on Crohn's disease and ulcerative colitis are still limited or insufficient. Moreover, there is a lack of studies delineating the mechanisms of DTT. Given that various targeted drugs have different targets among the extensive redundant inflammatory networks, DTT could result in various outcomes. In this review, we have summarized the current data on the safety, effectiveness, and clinical development status of novel targeted drugs related to refractory IBD, and have explored the mechanism of action of therapy. We have categorized therapeutic agents into "Therapeutic Agents Targeting Cellular Signaling Pathways" and "Therapeutic Agents Targeting Leukocyte Trafficking" based on the different therapeutic targets, and also by classifying therapeutic agents targeting the cellular signaling pathways into "JAK-dependent" and "JAK-independent," and placed the existing drug combinations into 3 categories based on their mechanisms, namely, overlapping, synergistic, and complementary effects. Lastly, we have proposed the possible mechanisms of DTT to conceive a theoretical framework for clinical decision-making and further drug development and research from an IBD standpoint.

Smad7 Antisense Oligonucleotide in Crohn's Disease: A Re-Evaluation and Explanation for the Discordant Results of Clinical Trials

In Crohn's disease (CD) and ulcerative colitis (UC), the major inflammatory bowel diseases (IBD) in human beings, the tissue-damaging inflammatory response is characterized by elevated levels of Suppressor of Mothers Against Decapentaplegic (Smad)7, an inhibitor of the immunosuppressive cytokine Transforming Growth Factor (TGF)-β1. Consistently, preclinical work in mouse models of IBD-like colitis showed that the knockdown of Smad7 with an antisense oligonucleotide (AS) attenuated the mucosal inflammation, thus paving the way for the development of an AS-containing pharmaceutical compound, named mongersen, for clinical use. The initial phase 1 and phase 2 studies showed that oral administration of mongersen was safe and effective in inducing clinical remission in active CD patients. However, subsequently, a large multicentered, randomized, double-blind, placebo-controlled, phase 3 trial was prematurely discontinued because of an interim analysis showing no effect of mongersen on the activity of CD. In this study we will discuss recent data showing that the majority of the batches of mongersen used in the phase 3 study were chemically different from those used in the previous clinical trials, with some of them being unable to knockdown Smad7 in cultured cells. The accumulating evidence highlights the need to maintain consistent manufacturing requirements for clinical AS, as well as the potential benefits of in vitro bioassays as a part of quality control. New clinical trials evaluating mongersen's impact on IBD using chemically homogenous batches will be needed to ascertain the therapeutic efficacy of such a drug.

Smad7 Antisense Oligonucleotide-Based Therapy in Crohn's Disease: Is it Time to Re-Evaluate?

Abundant preclinical work showed that in Crohn’s disease (CD), the defective activity of the immunosuppressive cytokine tumor necrosis factor (TGF)-β1 due to high levels of the intracellular inhibitor Smad7 contributes to amplify the tissue-damaging inflammatory response. Consistently, phase I and II studies documented clinical and endoscopic benefit in active CD patients treated with mongersen, an oral antisense oligonucleotide targeting Smad7. However, a multicenter, randomized, double-blind, placebo-controlled, phase III study was prematurely discontinued as a futility analysis showed that mongersen was not effective in CD patients. The reasons why the phase III study failed despite the fact that previous clinical trials documented the efficacy of the drug remain unknown. The primary objective of this Viewpoint was to provide clues about the factors explaining discrepancies among the clinical trials. We illustrate the recent data indicating that the various batches of mongersen, used during the phase III program, are chemically different, with some of them being unable to downregulate Smad7 expression. Overall, these findings suggest the necessity of new clinical studies to further evaluate the efficacy of chemically homogenous batches of mongersen in patients with inflammatory bowel diseases (IBDs), and, at the same time, they can help understand the failure of other clinical trials with antisense oligonucleotides in IBD (i.e. alicaforsen).

Inhomogeneous Diastereomeric Composition of Mongersen Antisense Phosphorothioate Oligonucleotide Preparations and Related Pharmacological Activity Impairment

Mongersen is a 21-mer antisense oligonucleotide designed to downregulate Mothers against decapentaplegic homolog 7 (SMAD7) expression to treat Crohn's disease. Mongersen was manufactured in numerous batches at different scales during several years of clinical development, which all appeared identical, using common physicochemical analytical techniques, while only phosphorous-31 nuclear magnetic resonance (³¹P-NMR) in solution showed marked differences. Close-up analysis of 27 mongersen batches revealed marked differences in SMAD7 downregulation in a cell-based assay. Principal component analysis of ³¹P-NMR profiles showed strong correlation with SMAD7 downregulation and, therefore, with pharmacological efficacy in vitro. Mongersen contains 20 phosphorothioate (PS) linkages, whose chirality (Rp/Sp) was not controlled during manufacturing. A different diastereomeric composition throughout batches would lead to superimposable analytical data, but to distinct ³¹P-NMR profiles, as indeed we found. We tentatively suggest that this may be the origin of different biological activity. As similar manifolds are expected for other PS-based oligonucleotides, the protocol described here provides a general method to identify PS chirality issues and a chemometric tool to score each preparation for this elusive feature.

A Pharmacological Batch of Mongersen that Downregulates Smad7 is Effective as Induction Therapy in Active Crohn's Disease: A Phase II, Open-Label Study

BACKGROUND

A recent phase III trial did not confirm the previous clinical and endoscopic improvements seen in patients with Crohn's disease (CD) receiving Mongersen, an oral Smad7 antisense oligonucleotide. Factors accounting for such a discrepancy are unknown.

OBJECTIVE

Our objective was to further assess whether Mongersen was effective as induction therapy in active CD and evaluate the in vitro inhibitory effect of various batches of Mongersen used in the previous and present trials on Smad7 expression.

METHODS

In a phase II, open-label study, 18 patients with active CD (Crohn's Disease Activity Index [CDAI] score > 220 and evidence of endoscopic lesions) received Mongersen 160 mg/day for 12 weeks. The rates of clinical remission, defined as CDAI < 150, and clinical response, defined as a CDAI score decrease ≥ 100, were evaluated at week 4, 8, and 12. The fraction of circulating CCR9-expressing leukocytes was assessed by flow cytometry. Smad7 expression was evaluated in the human colorectal cancer cell line HCT-116 transfected with different batches of Mongersen using real-time polymerase chain reaction (PCR) and Western blotting, RESULTS: The proportions of patients experiencing clinical remission were 38.9%, 55.6%, and 50.0% at week 4, 8, and 12, respectively. At the same time points, the rates of clinical response were 72.2%, 77.8%, and 77.8%, respectively. Mongersen reduced the percentages of CCR9-expressing CD45+ cells. The batch of Mongersen used in this study, but not two batches used in the phase III study, inhibited Smad7 expression in HCT-116 cells.

CONCLUSIONS

The present findings support the clinical benefit of Mongersen in active CD and show that various batches manufactured during the GED0301 program differ in their ability to inhibit in vitro Smad7.

TRIAL REGISTRATION NUMBER

NCT02685683; EudraCT 2015-001693-18.

Treatment of Intestinal Inflammation With Epicutaneous Immunotherapy Requires TGF-β and IL-10 but Not Foxp3+ Tregs

Background: Inflammatory bowel disease (IBD) involves an increase in T effector cells in the intestines that disrupts the normal balance with T regulatory cells (Tregs). A therapy that restores this balance has the potential to treat IBD. We have shown that epicutaneous exposure to OVA induces Tregs that are able to induce tolerance. The Tregs also migrate to the intestines where they alleviate colitis in mice, demonstrating the potential for skin induced Tregs to treat intestinal inflammation. We investigated the role of Foxp3, IL-10, and TGF-β in the suppression of colitis by epicutaneous immunotherapy (ET). Methods: RAG1^-/- mice were transferred with CD4⁺CD45RB^hi T cells from wild type mice to induce colitis. To determine whether Foxp3⁺ Tregs, IL-10-, or TGF-β-producing Tregs were necessary, Foxp3-DTR, IL-10^-/-, or CD4-dnTGFBRII mice were immunized with OVA and OVA TCR enriched T cells were added. As control groups, some mice were given OVA TCR enriched T cells from wild type mice or no OVA TCR enriched T cells. Half of the mice in each group were then exposed on the skin to Viaskin patches containing OVA weekly for 3 weeks. Mice given OVA TCR enriched T cells from Foxp3-DTR mice were given diphtheria toxin (DT) or not in addition to ET. Mice were assessed for weight loss, colon length, colonic cytokine production, and histological inflammation. Results: ET, after injection with OVA TCR enriched T cells derived from wild type mice, prevented weight loss, decreased colonic inflammatory cytokine production and histological colitis. ET in the absence of the OVA TCR enriched T cells did not alleviate colitis. ET, after injection with OVA TCR enriched T cells derived from Foxp3-DTR mice, prevented weight loss, decreased colonic inflammatory cytokine production, and histological colitis. Ablation with DT did not impair the ability of ET to alleviate colitis. ET failed to alleviate colitis when OVA TCR enriched T cells were derived from IL-10^-/- or CD4-dnTGFBRII mice. Conclusions: ET through induction of Tregs, which produce IL-10 and TGF-β, could be a promising treatment for IBD.

Intestinal Regulatory T Cells

Mucosal surfaces are distinctive sites exposed to environmental, dietary, and microbial antigens. Particularly in the gut, the host continuously actively adapts via complex interactions between the microbiota and dietary compounds and immune and other tissue cells. Regulatory T cells (Tregs) are critical for tuning the intestinal immune response to self- and non-self-antigens in the intestine. Its importance in intestinal homeostasis is illustrated by the onset of overt inflammation caused by deficiency in Treg generation, function, or stability in the gut. A substantial imbalance in Tregs has been observed in intestinal tissue during pathogenic conditions, when a tightly regulated and equilibrated system becomes dysregulated and leads to unimpeded and chronic immune responses. In this chapter, we compile and critically discuss the current knowledge on the key factors that promote Treg-mediated tolerance in the gut, such as those involved in intestinal Treg differentiation, specificity and suppressive function, and their immunophenotype during health and disease. We also discuss the current state of knowledge on Treg dysregulation in human intestine during pathological states such as inflammatory bowel disease (IBD), necrotizing enterocolitis (NEC), graft-versus-host disease (GVHD), and colorectal cancer (CRC), and how that knowledge is guiding development of Treg-targeted therapies to treat or prevent intestinal disorders.

Controlling Gut Inflammation by Restoring Anti-Inflammatory Pathways in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is caused by a dysregulated immune response against normal components of the intestinal microflora combined with defective functioning of anti-inflammatory pathways. Currently, all therapies approved for IBD manipulate the immune system by inhibiting pro-inflammatory mechanisms, such as tumor necrosis factor-α, gut-homing α4β7 integrin, interleukin-12/interleukin-23, and Janus kinases. However, some IBD patients are non-responders to these drugs, which are also associated with serious side effects. Thus, it has been hypothesized that therapies aimed at restoring anti-inflammatory signals, by exploiting the tolerogenic potential of cytokines (interleukin-10, transforming growth factor-β, granulocyte macrophage colony-stimulating factor), immune cells (regulatory T cells, tolerogenic dendritic cells), or mesenchymal stem cells, might offer promising results in terms of clinical efficacy with fewer side effects. In this review, we provide new insights into putative novel treatments aimed at restoring anti-inflammatory signaling pathways in IBD.

Very early onset IBD: novel genetic aetiologies

PURPOSE OF REVIEW

To summarize the current understanding and recent advances on the genetic aetiology in the pathogenesis of very early onset inflammatory bowel disease (VEO-IBD).

RECENT FINDINGS

IBD is a chronic disorder of the gastrointestinal tract whose manifestation is a result of complex interactions between genetics, environment, immune system and microbial flora. Over 230 IBD risk loci have been reported in genome wide association studies but the genetic contribution of the majority of these loci in the manifestation of IBD is very low. Patients with VEO-IBD present with a more severe disease than older patients, characterized by poor prognosis and failure of conventional therapy. Recent studies have reported several monogenic diseases with high penetrance that present with IBD and IBD-like intestinal manifestations and overlap with primary immunodeficiencies. Increasing body of evidence supports a prominent role of genetics in the onset of VEO-IBD. New genetic variants and diagnoses in VEO-IBD are reviewed and current challenges in therapy with potential strategy to manage the disease are discussed.

SUMMARY

Functional analysis of the genes implicated in monogenic IBD has increased the understanding of the underlying pathobiological mechanism of the disease. This knowledge can be used to personalize medicine for specific patients, improving the standard of care and quality of life.

Chemokines and Chemokine Receptors as Therapeutic Targets in Inflammatory Bowel Disease; Pitfalls and Promise

The principal targets for anti-chemokine therapy in inflammatory bowel disease (IBD) have been the receptors CCR9 and CXCR3 and their respective ligands CCL25 and CXCL10. More recently CCR6 and its ligand CCL20 have also received attention, the expression of the latter in enterocytes being manipulated through Smad7 signalling. These pathways, selected based on their fundamental role in regulating mucosal immunity, have led to the development of several therapeutic candidates that have been tested in early phase clinical trials with variable clinical efficacy. In this article, we appraise the status of chemokine-directed therapy in IBD, review recent developments, and nominate future areas for therapeutic focus.

Review article: novel oral-targeted therapies in inflammatory bowel disease

BACKGROUND

There is a great unmet clinical need for efficacious, tolerable, economical and orally administrated drugs for the treatment of inflammatory bowel disease (IBD). New therapeutic avenues have become possible including the development of medications that target specific genetic pathways found to be relevant in other immune mediated diseases.

AIMS

To provide an overview of recent clinical trials for new generation oral targeted medications that may have a future role in IBD management.

METHODS

Pubmed and Medline searches were performed up to 1 March 2018 using keywords: "IBD", "UC", "CD", "inflammatory bowel disease" "ulcerative colitis", "Crohn's disease" in combination with "phase", "study", "trial" and "oral". A manual search of the clinical trial register, article reference lists, abstracts from meetings of Digestive Disease Week, United European Gastroenterology Week and ECCO congress were also conducted.

RESULTS

In randomised controlled trials primary efficacy endpoints were met for tofacitinib (JAK 1/3 inhibitor-phase III), upadacitinib (JAK 1 inhibitor-phase II) and AJM300 (α4-integrin antagonist-phase II) in ulcerative colitis. Ozanimod (S1P receptor agonist-phase II) also demonstrated clinical remission. For Crohn's disease, filgotinib (JAK1 inhibitor-phase II) met primary endpoints and laquinimod (quinolone-3-carboxide small molecule-phase II) was also efficacious. Trials using mongersen (SMAD7 inhibitor) and vidofludimus (dihydroorotate dehydrogenase inhibitor) have been halted.

CONCLUSIONS

This is potentially the start of an exciting new era in which multiple therapeutic options are at the disposal of physicians to treat IBD on an individualised basis. Head-to-head studies with existing treatments and longer term safety data are needed for this to be possible.

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.

Emerging oral targeted therapies in inflammatory bowel diseases: opportunities and challenges

To improve quality of life and prevent long-term risks in patients with inflammatory bowel diseases (IBDs: Crohn's disease, ulcerative colitis), it is essential to suppress inflammatory activity adequately. However, corticosteroids are only suitable for therapy of acute flares and the evidence for positive effects of immunosuppressive substances like azathioprine or 6-mercapropurine is mainly limited to maintenance of remission. In addition, only subgroups of patients benefit from biologicals targeting tumour necrosis factor α or α4β7 integrins. In summary, until now the disease activity is not sufficiently controlled in a relevant fraction of the patients with IBD. Thus, there is an urge for the development of new substances in the therapy of ulcerative colitis and Crohn's disease. Fortunately, new oral and parenteral substances are in the pipeline. This review will focus on oral substances, which have already passed phase II studies successfully at this stage. In this article, we summarize data regarding AJM300, phosphatidylcholine (LT-02), mongersen, ozanimod, filgotinib and tofacitinib. AJM300 and ozanimod were tested in patients with ulcerative colitis and target lymphocyte trafficking through inhibition of the α subunit of integrin, respectively binding to the sphingosine-1-phosphate receptor (subtypes 1 and 5) on lymphocytes. Mongersen was utilized in patients with Crohn's disease and accelerates the degradation of SMAD7 mRNA, which consequently strengthens the mainly anti-inflammatory signalling pathway of transforming growth factor β1. Various Janus kinase (JAK) inhibitors were developed, which inhibit the intracellular signalling pathway of cytokines. For example, the JAK1 blocker filgotinib was tested in Crohn's disease, whereas the JAK1/3 inhibitor tofacitinib was tested in clinical trials for both Crohn's disease and ulcerative colitis. A different therapeutic approach is the substitution of phosphatidylcholine (LT-02), which might recover the colonic mucus. Taken together, clinical trials with these new agents have opened avenues for further clinical studies and it can be expected that at least some of these agents will be finally approved for clinical therapy.

The Role of Cytokines in the Fibrotic Responses in Crohn's Disease

Crohn’s disease is an idiopathic disorder of the gut thought to be caused by a combination of environmental and genetic factors in susceptible individuals. It is characterized by chronic transmural inflammation of the terminal ileum and colon, with typical transmural lesions. Complications, including fibrosis, mean that between 40 and 70% of patients require surgery in the first 10 years after diagnosis. Presently, there is no evidence that the current therapies which dampen inflammation modulate or reverse intestinal fibrosis. In this review, we focus on cytokines that may lead to fibrosis and stenosis and the contribution of experimental models for understanding and treatment of gut fibrosis.

TGF-β in inflammatory bowel disease: a key regulator of immune cells, epithelium, and the intestinal microbiota

Inflammatory bowel disease (IBD) is defined as chronic intestinal inflammation, and includes ulcerative colitis and Crohn's disease. Multiple factors are involved in the pathogenesis of IBD, and the condition is characterized by aberrant mucosal immune reactions to intestinal microbes in genetically susceptible hosts. Transforming growth factor-β (TGF-β) is an immune-suppressive cytokine produced by many cell types and activated by integrins. Active TGF-β binds to its receptor and regulates mucosal immune reactions through the TGF-β signaling pathway. Dysregulated TGF-β signaling is observed in the intestines of IBD patients. TGF-β signal impairment in specific cell types, such as T-cells and dendritic cells, results in spontaneous colitis in mouse models. In addition, specific intestinal microbes contribute to immune homeostasis by modulating TGF-β production. In this review, we describe the role of TGF-β in intestinal immunity, focusing on immune cells, epithelium, and intestinal microbes. In addition, we present potential therapeutic strategies for IBD that target TGF-β.

Etiopathogenesis of inflammatory bowel disease: today and tomorrow

PURPOSE OF REVIEW

Crohn's disease and ulcerative colitis, the two major forms of inflammatory bowel disease (IBD), represent chronic diseases of unknown cause, and they are regarded as prototypical complex diseases. Despite all the recent advances, a complete appreciation of the pathogenesis of IBD is still limited. In this review, we present recent information contributing to a better understanding of mechanisms underlying IBD.

RECENT FINDINGS

Here, we attempt to highlight novel environmental triggers, data on the gut microbiota, its interaction with the host, and the potential influence of diet and food components. We discuss recent findings on defective signaling pathways and the potential effects on the immune response, and we present new data on epigenetic changes, inflammasome, and damage-associated molecular patterns associated with IBD.

SUMMARY

The continuing identification of several epigenetic, transcriptomic, proteomic, and metabolomic alterations in patients with IBD reflects the complex nature of the disease and suggests the need for innovative approaches such as systems biology for identifying novel relevant targets in IBD.

Tofacitinib for induction and maintenance therapy of Crohn's disease: results of two phase IIb randomised placebo-controlled trials

OBJECTIVE

Tofacitinib is an oral, small-molecule Janus kinase inhibitor that is being investigated for IBD. We evaluated the efficacy and safety of tofacitinib for induction and maintenance treatment in patients with moderate-to-severe Crohn's disease (CD).

DESIGN

We conducted two randomised, double-blind, placebo-controlled, multicentre phase IIb studies. Adult patients with moderate-to-severe CD were randomised to receive induction treatment with placebo, tofacitinib 5 or 10 mg twice daily for 8 weeks. Those achieving clinical response-100 or remission were re-randomised to maintenance treatment with placebo, tofacitinib 5 or 10 mg twice daily for 26 weeks. Primary endpoints were clinical remission at the end of the induction study, and clinical response-100 or remission at the end of the maintenance study.

RESULTS

180/280 patients randomised in the induction study were enrolled in the maintenance study. At week 8 of induction, the proportion of patients with clinical remission was 43.5% and 43.0% with 5 and 10 mg twice daily, respectively, compared with 36.7% in the placebo group (p=0.325 and 0.392 for 5 and 10 mg twice daily vs placebo). At week 26 of maintenance, the proportion of patients with clinical response-100 or remission was 55.8% with tofacitinib 10 mg twice daily compared with 39.5% with tofacitinib 5 mg twice daily and 38.1% with placebo (p=0.130 for 10 mg twice daily vs placebo). Compared with placebo, the change in C-reactive protein from baseline was statistically significant (p<0.0001) with 10 mg twice daily after both induction and maintenance treatments.

CONCLUSIONS

Primary efficacy endpoints were not significantly different from placebo, although there was evidence of a minor treatment effect. No new safety signals were observed for tofacitinib.

TRIAL REGISTRATION NUMBERS

NCT01393626 and NCT01393899.

[Role of Inhibitory Transforming Growth Factor-β Signal Smad7 in Helicobacter pylori-associated Gastric Damage]

Background/Aims

Transforming growth factor-beta (TGF-β) is a cytokine implicated in the susceptibility, development, and progression of gastrointestinal cancer and certain other neoplasms. In the later stages of cancer, TGF-β not only acts as a bystander of host-immune response, but also contributes to cell growth, invasion, and metastasis. In the current study, we generated gastric mucosal cells that stably express Smad7, and explored the Helicobacter pylori-associated biological changes between mock-transfected and Smad7-transfected RGM1 cells.

Methods

RGM1 cells stably transfected with Smad7 were infected with H. pylori, and molecular changes in apoptotic markers and inflammatory mediators were examined. Several candidate genes were explored in Smad7-overexpressing cells after H. pylori infection.

Results

Overexpression of Smad7 in RGM1 cells significantly increased the H. pylori-induced cytotoxicity compared to mock-transfected cells. Exaggerated increases in inflammatory mediators, cyclooxygenase 2, inducible NO synthase, and augmented apoptosis were noted in Smad7-overexpressing cells, whereas mitigated heme oxygenase 1 was noted in Smad7- overexpressing cells. These phenomena were reversed in cells transfected with Smad7 siRNA.

Conclusions

These data suggest that inhibition of Smad7 is a possible target for mitigating H. pylori-associated inflammation.

Genetic risk variants as therapeutic targets for Crohn's disease

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.

Preclinical and Clinical Advances of GalNAc-Decorated Nucleic Acid Therapeutics

A main challenge in realizing the full potential of nucleic acid therapeutics is efficient delivery of them into targeted tissues and cells. N-acetylgalactosamine (GalNAc) is a well-defined liver-targeted moiety benefiting from its high affinity with asialoglycoprotein receptor (ASGPR). By conjugating it directly to the oligonucleotides or decorating it to a certain delivery system as a targeting moiety, GalNAc has achieved compelling successes in the development of nucleic acid therapeutics in recent years. Several oligonucleotide modalities are undergoing pivotal clinical studies, followed by a blooming pipeline in the preclinical stage. This review covers the progress of GalNAc-decorated oligonucleotide drugs, including siRNAs, anti-miRs, and ASOs, which provides a panorama for this field.

Emerging biologics in inflammatory bowel disease

Early biologic therapy is recommended in patients with inflammatory bowel disease and poor prognostic factors and in those refractory to conventional medications. Anti-tumor necrosis factor (anti-TNF) agents are the most commonly used biologic agents. However, some patients may not have an initial response to anti-TNF therapy, and one-third will develop loss of response over time. Anti-TNF drugs can also be associated with side effects. In addition, the use of biologics is currently limited by their cost, especially in developing countries. A number of new therapeutic targets, including novel small molecules, and cellular therapy are available or under investigation. These novel molecules include oral Janus kinase (JAK) inhibitor (tofacitinib), interleukin inhibitor (ustekinumab), oral SMAD7 antisense oligonucleotide (mongersen), and anti-integrin inhibitors (vedolizumab). Here, we review the mechanisms of action, the efficacy, and the safety data of these novel agents. Biological products that are highly similar to reference biologic products whose patents have expired-also known as "biosimilars"-can be produced at lower cost with similar efficacy, and are also available for the treatment of IBD. We review the efficacy data for such agents as well.

Novel Targeted Therapies for Inflammatory Bowel Disease

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

Increased duodenal expression of miR-146a and -155 in pediatric Crohn’s disease

AIM: To evaluate the role of microRNA (miR)-146a, -155 and -122 in the duodenal mucosa of pediatric patients with Crohn’s disease (CD) and the effect of transforming growth factor-β (TGF-β) on these miRs in duodenal epithelial and fibroblast cells.

METHODS: Formalin-fixed, paraffin-embedded biopsies derived from the macroscopically inflamed (CD inflamed: n = 10) and intact (CD intact: n = 10) duodenal mucosa of pediatric CD patients and control children (C: n = 10) were examined. Expression of miR-146a, -155 and -122 was determined by real-time polymerase-chain reaction (PCR). The expression of the above miRs was investigated in recombinant human TGF-β (1 nmol/L, 24 h) or vehicle treated small intestinal epithelial cells (CCL-241) and primary duodenal fibroblast cells derived from healthy children as well.

RESULTS: Expression of miR-146a was significantly higher in the inflamed duodenal mucosa compared to the intact duodenal mucosa of children with CD (CD inflamed: 3.21 ± 0.50 vs CD intact: 0.62 ± 0.26, P≤ 0.01) and to the control group (CD inflamed: 3.21 ± 0.50 vs C: 1.00 ± 0.33, P≤ 0.05). The expression of miR-155 was significantly increased in the inflamed region of the duodenum compared to the control group (CD inflamed: 4.87 ± 1.02 vs Control: 1.00 ± 0.40, P≤ 0.001). The expression of miR-122 was unchanged in the inflamed or intact mucosa of CD patients compared to controls. TGF-β treatment significantly decreased the expression of miR-155 in small intestinal epithelial cells (TGF-β: 0.7 ± 0.083 vs Control: 1 ± 0.09, P≤ 0.05) and also the expression of miR-146a (TGF-β: 0.67 ± 0.04 vs Control: 1 ± 0.15, P≤ 0.01) and miR-155 (TGF-β: 0.72 ± 0.09 vs Control: 1 ± 0.06, P≤ 0.05) in primary duodenal fibroblasts compared to corresponding vehicle treated controls. TGF-β treatment did not influence the expression of miR-122.

CONCLUSION: The elevated expression of miR-146a and -155 in the inflamed duodenal mucosa of CD patients suggests the role of these miRs in the pathomechanism of inflammatory bowel disease. Anti-inflammatory TGF-β plays an important role in the regulation of the expression of these miRs.

New and Evolving Immunotherapy in Inflammatory Bowel Disease

BACKGROUND

Crohn's disease and ulcerative colitis are chronic inflammatory disorders associated with a dysregulated adaptive and innate immune response to gut commensals in genetically susceptible individuals. The pathogenesis of inflammatory bowel disease is complex, and the disease is characterized by significant phenotypic and genotypic heterogeneity.

SUMMARY

The introduction of anti-TNF biologics has resulted in improved clinical outcomes in patients with severe and moderately severe disease, but the current treatment paradigm continues to depend on systemic immunosuppression (steroids and immunomodulators) and surgical intervention in a significant number of patients, underscoring a significant unmet need. More recently, a number of genetic and immunologic abnormalities have been unraveled including aberrant intestinal mucosal defense function, abnormal intestinal permeability, dysregulated bacterial antigen processing by macrophages and presentation to T cells, cellular immune regulation and signaling, cytokine production, and leukocyte trafficking.

KEY MESSAGES

Understanding these molecular mechanisms and effector pathways presents an opportunity for the development of new and improved targeted therapies.

Gene expression alterations in inflamed and unaffected colon mucosa from patients with mild inflammatory bowel disease

An endoscopic examination is currently the most reliable method for monitoring disease activity in patients with inflammatory bowel disease (IBD). However, endoscopic evaluations are unable to detect mucosal inflammation at the earliest stages. The present study aimed to evaluate the molecular profiles of inflamed and unaffected colon mucosa from patients with mild Crohn's disease (CD) and ulcerative colitis (UC), in order to identify a more sensitive method for monitoring mucosal impairment. Patients were recruited and colon biopsies from the inflamed and the normal‑appearing mucosa of patients with mild IBD were obtained by colonoscopy. Gene expression analysis was performed using microarrays, after which Gene Ontology and clustering were performed using bioinformatics. In addition, the levels of inflammatory cytokines were analyzed by reverse transcription‑quantitative polymerase chain reaction. A total of 620 genes in the inflamed and 210 genes in the unaffected colon mucosa with at least a 3‑fold change, as compared with healthy controls, were detected in patients with mild CD, and 339 genes in the inflamed and 483 genes in the unaffected colon mucosa were detected in patients with mild UC. Heat mapping demonstrated a similarity in the gene alteration patterns, and altered transcripts overlapped, between the inflamed and unaffected colon mucosa. Interferon‑γ and interleukin‑17 mRNA levels were comparably elevated in the inflamed and unaffected colon mucosa from patients with IBD. Marked gene expression alterations were detected in the inflamed and unaffected colon mucosa from patients with mild IBD, and these showed marked similarity and overlap between the two groups. The results of the present study suggested that inflammation was not limited to the endoscopic lesions and that gene expression profiling may be considered a sensitive tool for monitoring mucosal inflammation, predicting relapses and optimizing therapeutic strategies for patients with IBD.