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

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

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

Tackling Inflammatory Bowel Diseases: Targeting Proinflammatory Cytokines and Lymphocyte Homing

Inflammatory bowel diseases (IBDs) are characterized by chronic inflammatory disorders that are a result of an abnormal immune response mediated by a cytokine storm and immune cell infiltration. Proinflammatory cytokine therapeutic agents, represented by TNF inhibitors, have developed rapidly over recent years and are promising options for treating IBD. Antagonizing interleukins, interferons, and Janus kinases have demonstrated their respective advantages in clinical trials and are candidates for anti-TNF therapeutic failure. Furthermore, the blockade of lymphocyte homing contributes to the excessive immune response in colitis and ameliorates inflammation and tissue damage. Factors such as integrins, selectins, and chemokines jointly coordinate the accumulation of immune cells in inflammatory regions. This review assembles the major targets and agents currently targeting proinflammatory cytokines and lymphatic trafficking to facilitate subsequent drug development.

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

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

Emerging therapeutic options in inflammatory bowel disease

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

Opportunities to Target T Cell Trafficking in Pediatric Inflammatory Bowel Disease

T cell subsets are considered central orchestrators of inflammation and homeostasis in the intestine and are established targets for the treatment of inflammatory bowel disease. While approaches aimed at the neutralization of T cell effector cytokines have provided significant benefits for pediatric and adult patients, more recent strategies aimed at inhibiting the infiltration of pathogenic T cell subsets have also emerged. In this review, we describe current knowledge surrounding the function of T cell subsets in pediatric inflammatory bowel disease and outline approaches aimed at targeting T cell trafficking to the intestine which may represent a new treatment option for pediatric inflammatory bowel disease.

Cobitolimod for moderate-to-severe, left-sided ulcerative colitis (CONDUCT): a phase 2b randomised, double-blind, placebo-controlled, dose-ranging induction trial

BACKGROUND

Cobitolimod is a topically administered, DNA-based oligonucleotide that activates Toll-like receptor 9 (TLR9), and previous research has shown clinical efficacy in patients with moderate-to-severe ulcerative colitis. Here we assessed the efficacy and safety of different dose regimens of cobitolimod for induction therapy in patients with moderate-to-severe, left-sided ulcerative colitis.

METHODS

CONDUCT was a randomised, double-blind, five-arm, placebo-controlled, dose-ranging phase 2b study that recruited patients with moderate-to-severe, left-sided ulcerative colitis, with inadequate response to conventional or biological therapies, from 91 hospitals or outpatient clinics in 12 European countries. Eligible patients had a Mayo score of 6-12 with a centrally read endoscopic subscore (modified to exclude friability from grade 1) of 2 or higher and no individual subscore of less than 1, and confirmation of left-sided disease. Patients were randomised (1:1:1:1:1; block size of ten) via a computer-generated schedule and centralised interactive voice and web response system to receive rectal enemas of cobitolimod at 31 mg, 125 mg, or 250 mg at weeks 0 and 3 (2 × 31 mg, 2 × 125 mg, and 2 × 250 mg groups), cobitolimod at 125 mg at weeks 0, 1, 2, and 3 (4 × 125 mg group), or placebo. Randomisation was stratified by current glucocorticosteroid and previous tumour necrosis factor inhibitor treatment. Patients and all study personnel were masked to treatment allocation. The primary endpoint was the proportion of patients achieving clinical remission (Mayo subscores for rectal bleeding of 0, for stool frequency of 0 or 1 [with ≥1-point decrease from baseline], and for endoscopy of 0 or 1 [excluding friability]) at week 6. The primary analysis (based on intention to treat) and safety analysis were done in all randomly assigned patients who received at least one dose of active study drug or placebo. In this exploratory study, statistical tests were one-sided; p values of less than 0·10 were regarded as statistically significant, with no adjustment for multiplicity. This study is registered with ClinicalTrials.gov, NCT03178669, and is completed; the results here represent the final analysis.

FINDINGS

213 patients were randomly assigned between June 30, 2017, and June 26, 2019. Of these, 211 patients received study treatment: 40 in the cobitolimod 2 × 31 mg group, 43 in the 2 × 125 mg group, 42 in the 4 × 125 mg group, 42 in the 2 × 250 mg group, and 44 in the placebo group. A greater proportion of patients were in clinical remission at week 6 in the cobitolimod 2 × 250 mg group than in the placebo group (nine [21%] of 42 patients vs three [7%] of 44; odds ratio [OR] 3·8 [80% CI 1·5-9·5]; one-sided p=0·025). We identified no significant difference in the proportion of patients with clinical remission in the cobitolimod 2 × 31 mg group (five [13%] of 40 patients; OR 2·0 [80% CI 0·7-5·5], p=0·18), 2 × 125 mg group (two [5%] of 43; 0·7 [0·2-2·2], p=0·66), or 4 × 125 mg (four [10%] of 42; 1·4 [0·5-3·9], p=0·33) compared with the placebo group. Treatment-emergent adverse events occurred in 21 (48%) patients in the placebo group, ten (25%) patients in the cobitolimod 2 × 31 mg group, 17 (40%) patients in the 2 × 125 mg group, 15 (36%) patients in the 4 × 125 mg group, and 18 (43%) patients in the 2 × 250 mg group. Severe adverse events occurred in eight (4%) of 211 patients (worsening of ulcerative colitis [seven patients] and abdominal hernia and wound dehiscence [one patient]). Ten patients (two [5%] in the placebo group, two [5%] in the cobitolimod 2 × 31 mg group, two [5%] in the 4 × 125 mg, and four [10%] in the 2 × 250 mg group) had a total of 13 serious adverse events; these were worsening of ulcerative colitis (eight events) and pruritus, rash, abdominal hernia, fascia dehiscence, and deep vein thrombosis (one event each). One patient in the placebo group died from total organ failure after receiving a colectomy for a serious adverse event of disease worsening.

INTERPRETATION

Two topical administrations of cobitolimod 250 mg were well tolerated and more effective than placebo in inducing clinical remission 6 weeks after the start of treatment. TLR9 activation is a promising novel therapeutic target in ulcerative colitis and warrants further testing, with phase 3 trials of cobitolimod planned.

FUNDING

InDex Pharmaceuticals.

Small molecule drugs in the treatment of inflammatory bowel diseases: which one, when and why? - a systematic review

In the 'treat-to-target' era of inflammatory bowel disease (IBD) management, small molecule drugs (SMDs) represent a promising alternative to biomolecular drugs. Moreover, increasing failure rates of anti-tumor necrosis factor α agents have contributed to the development of new molecules with different mechanisms of action and bioavailability. This review focuses on the positioning of new, orally targeted therapies in the treatment algorithm of both Crohn's disease (CD) and ulcerative colitis (UC), with special consideration to their efficacy and safety. We performed a comprehensive search of PubMed and clinical trial registries to identify randomized controlled trials assessing SMDs in adult patients with moderate-to-severe IBD, irrespective of previous exposure to other biologics. In this review, we included 15 double-blind, placebo-controlled trials that assessed the efficacy and safety of Janus kinase inhibitors, sphingosine-1-phosphate modulators (S1P), SMAD blockers, phosphodiesterase 4 inhibitors and α-4 antagonists. The primary endpoints in UC were achieved for tofacitinib in the phase III OCTAVE study and AJM-300, with a favorable safety profile. S1P receptor agonists, such as etrasimod and ozanimod, demonstrated favorable results in induction studies. For CD, filgotinib and upadacitinib also met the primary outcome criteria. Available data have demonstrated so far that SMDs have an advantageous safety and efficacy profile. However, their use in a clinical setting will eventually require a personalized, mechanism-based therapeutic approach.

Immune cell trafficking and retention in inflammatory bowel disease: mechanistic insights and therapeutic advances

Intestinal immune cell trafficking has been identified as a central event in the pathogenesis of inflammatory bowel diseases (IBD). Intensive research on different aspects of the immune mechanisms controlling and controlled by T cell trafficking and retention has led to the approval of the anti-α4β7 antibody vedolizumab, the ongoing development of a number of further anti-trafficking agents (ATAs) such as the anti-β7 antibody etrolizumab or the anti-MAdCAM-1 antibody ontamalimab and the identification of potential future targets like G-protein coupled receptor 15. However, several aspects of the biology of immune cell trafficking and regarding the mechanism of action of ATAs are still unclear, for example, which impact these compounds have on the trafficking of non-lymphocyte populations like monocytes and how precisely these therapies differ with regard to their effect on immune cell subpopulations. This review will summarise recent advances of basic science in the field of intestinal immune cell trafficking and discuss these findings with regard to different pharmacological approaches from a translational perspective.

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.

Mesyl phosphoramidate antisense oligonucleotides as an alternative to phosphorothioates with improved biochemical and biological properties

Forty years of research have shown that antisense oligonucleotides have great potential to target mRNAs of disease-associated genes and noncoding RNAs. Among the vast number of oligonucleotide backbone modifications, phosphorothioate modification is the most widely used in research and the clinic. However, along with their merits are notable drawbacks of phosphorothioate oligonucleotides, including decreased binding affinity to RNA, reduced specificity, and increased toxicity. Here we report the synthesis and in vitro evaluation of the DNA analog mesyl phosphoramidate oligonucleotide. This oligonucleotide type recruits RNase H and shows significant advantages over phosphorothioate in RNA affinity, nuclease stability, and specificity in inhibiting key processes of carcinogenesis. Thus, mesyl phosphoramidate oligonucleotides may be an attractive alternative to phosphorothioates.

Here we describe a DNA analog in which the mesyl (methanesulfonyl) phosphoramidate group is substituted for the natural phosphodiester group at each internucleotidic position. The oligomers show significant advantages over the often-used DNA phosphorothioates in RNA-binding affinity, nuclease stability, and specificity of their antisense action, which involves activation of cellular RNase H enzyme for hybridization-directed RNA cleavage. Biological activity of the oligonucleotide analog was demonstrated with respect to pro-oncogenic miR-21. A 22-nt anti–miR-21 mesyl phosphoramidate oligodeoxynucleotide specifically decreased the miR-21 level in melanoma B16 cells, induced apoptosis, reduced proliferation, and impeded migration of tumor cells, showing superiority over isosequential phosphorothioate oligodeoxynucleotide in the specificity of its biological effect. Lower overall toxicity compared with phosphorothioate and more efficient activation of RNase H are the key advantages of mesyl phosphoramidate oligonucleotides, which may represent a promising group of antisense therapeutic agents.

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.