Current and emerging maintenance therapies for ulcerative colitis

Discovery and Optimization of Novel hDHODH Inhibitors for the Treatment of Inflammatory Bowel Disease

As a key rate-limiting enzyme in the de novo synthesis of pyrimidine nucleotides, human dihydroorotate dehydrogenase (hDHODH) is considered a known target for the treatment of autoimmune diseases, including inflammatory bowel disease (IBD). Herein, BAY 41-2272 with a 1H-pyrazolo[3,4-b]pyridine scaffold was identified as an hDHODH inhibitor by screening an active compound library containing 5091 molecules. Further optimization led to 2-(1-(2-chloro-6-fluorobenzyl)-1H-pyrrolo[2,3-b]pyridin-3-yl)-5-cyclopropylpyrimidin-4-amine (w2), which was found to be the most promising and drug-like compound with potent inhibitory activity against hDHODH (IC50 = 173.4 nM). Compound w2 demonstrated acceptable pharmacokinetic characteristics and alleviated the severity of acute ulcerative colitis induced by dextran sulfate sodium in a dose-dependent manner. Notably, w2 exerted better therapeutic effects on ulcerative colitis than hDHODH inhibitor vidofludimus and Janus kinase (JAK) inhibitor tofacitinib. Taken together, w2 is a promising hDHODH inhibitor for the treatment of IBD and deserves to be developed as a preclinical candidate.

Maintenance of Remission With Tofacitinib Therapy in Patients With Ulcerative Colitis

BACKGROUND & AIMS

Tofacitinib is an oral, small molecule Janus kinase inhibitor for the treatment of ulcerative colitis (UC). The efficacy and safety of tofacitinib in patients with moderate to severe UC, up to 1 year, have been reported. We investigated maintenance of efficacy in patients in remission after 52 weeks of maintenance treatment in the pivotal phase 3 study (OCTAVE Sustain); these patients received open-label, long-term treatment with tofacitinib 5 mg twice daily.

METHODS

Patients with moderate to severe UC who completed a 52-week, phase 3 maintenance study (OCTAVE Sustain) were eligible to enroll into the ongoing, phase 3, multicenter, open-label, long-term extension (OCTAVE Open). We analyzed data from 142 patients who were in remission following tofacitinib treatment in OCTAVE Sustain who received tofacitinib 5 mg twice daily during OCTAVE Open. We assessed efficacy (including remission [based on total Mayo score], endoscopic improvement, clinical response, and partial Mayo score up to month 36 of OCTAVE Open) and safety data.

RESULTS

After 12 months of tofacitinib 5 mg twice daily in OCTAVE Open, 68.3% of patients were in remission, 73.9% had endoscopic improvement, and 77.5% had a clinical response. At month 36, 50.4%, of the patients were in remission, 55.3% had endoscopic improvement, and 56.0% had a clinical response. The safety profile of tofacitinib 5 mg twice daily revealed no new safety risks associated with long-term exposure up to 36 months.

CONCLUSIONS

Efficacy endpoints were maintained for up to 36 months, regardless of prior tofacitinib dose, including patients who reduced from tofacitinib 10 mg to 5 mg twice daily upon OCTAVE Open entry. No new safety risks were identified. ClinicalTrials.gov: OCTAVE Sustain (NCT01458574); OCTAVE Open (NCT01470612).

Inflammatory bowel disease: tri-directional relationship between microbiota, immune system and intestinal epithelium

Human gut microbiota contributes to host nutrition and metabolism, sustains intestinal cell proliferation and differentiation, and modulates host immune system. The alterations in their composition lead to severe gut disorders, including inflammatory bowel disease (IBD) or inflammatory bowel syndrome (IBS). IBD including ulcerative colitis (UC) and Crohn's disease (CD) are gamut of chronic inflammatory disorders of gut, mediated by complex interrelations among genetic, environmental, and internal factors. IBD has debateable aetiology, however in recent years, exploring the central role of a tri-directional relationship between gut microbiota, mucosal immune system, and intestinal epithelium in pathogenesis is getting the most attention. Increasing incidences and early onset explains the exponential rise in IBD burden on health-care systems. Industrialization, hypersensitivity to allergens, lifestyle, hygiene hypothesis, loss of intestinal worms, and gut microbial composition, explains this shifted rise. Hitherto, the interventions modulating gut microbiota composition, microfluidics-based in vitro gastrointestinal models, non-allergic functional foods, nutraceuticals, and faecal microbiota transplantation (FMT) from healthy donors are some of the futuristic approaches for the disease management.

Role of Histologic Inflammation in the Natural History of Ulcerative Colitis

The goals of therapy for ulcerative colitis have moved from symptom improvement to mucosal healing, and finally histologic resolution. The natural history of histologic inflammation in ulcerative colitis progresses from initial cellular infiltration to architectural disruption and recovery on medical therapy. Many studies have linked histologic changes to clinical outcomes, providing prognostic value to histologic abnormalities. This review covers all these components.

Inflammatory Bowel Disease: An Overview of Immune Mechanisms and Biological Treatments

Inflammatory bowel diseases (IBD) are characterized by chronic inflammation of the intestinal tract associated with an imbalance of the intestinal microbiota. Crohn's disease (CD) and ulcerative colitis (UC) are the most widely known types of IBD and have been the focus of attention due to their increasing incidence. Recent studies have pointed out genes associated with IBD susceptibility that, together with environment factors, may contribute to the outcome of the disease. In ulcerative colitis, there are several therapies available, depending on the stage of the disease. Aminosalicylates, corticosteroids, and cyclosporine are used to treat mild, moderate, and severe disease, respectively. In Crohn's disease, drug choices are dependent on both location and behavior of the disease. Nowadays, advances in treatments for IBD have included biological therapies, based mainly on monoclonal antibodies or fusion proteins, such as anti-TNF drugs. Notwithstanding the high cost involved, these biological therapies show a high index of remission, enabling a significant reduction in cases of surgery and hospitalization. Furthermore, migration inhibitors and new cytokine blockers are also a promising alternative for treating patients with IBD. In this review, an analysis of literature data on biological treatments for IBD is approached, with the main focus on therapies based on emerging recombinant biomolecules.