P031 Therapeutic effect of OPS-2071 in a murine model of Crohn’s disease and in in vitro anti-inflammatory assays

Abstract

Abstract Background OPS-2071 is a novel fluoroquinolone that is currently in Phase 2 clinical trials for the evaluation of Crohn’s disease (CD) as an add-on therapy to standard of care. OPS-2071 has broad and potent antibacterial activity with low systemic absorption. It was previously investigated for the treatment of enteric infections, including Clostridium difficile. CD is an immune-mediated condition of unknown aetiology; however, studies suggest that an abnormal immune response against certain intestinal bacteria may trigger the development of chronic inflammation. In this study, we have evaluated the effect of OPS-2071 on both the murine T-cell-mediated colitis as well as its in vitro effect on the activity of immune cells. Methods Transfer of naïve T cells (CD4+CD62L+CD44−) into immunodeficiency mice induces autoimmune colitis. Two weeks following T-cell transfer, OPS-2071, sulfasalazine and anti-IL12/23 p40 antibody were administered for 3 weeks, followed by assessment of efficacy evaluation by histological score and inflammatory index. In vitro inhibitory action for TNF-α production was assayed using LPS-stimulated human peripheral blood cells and THP-1 macrophages. The effect on T-cell activation and cytokine production (TNF-α, IFN-γ) was examined using anti-CD2/CD3/CD28 antibody-loaded beads-stimulated human peripheral blood mononuclear cells. In vitro activity against bacteria considered to be a potential cause of IBD such as M. avium sub. paratuberculosis, Klebsiella pneumonia, etc., was also tested. Results OPS-2071 and anti-IL12/23 p40 antibody significantly reduced both histological score (control: 9.0, OPS: 4.7, anti-IL12: 4.3, p < 0.01) and inflammatory index (control: 58.3 ± 3.7 mg/cm, OPS: 25.9 ± 1.4 mg/cm, anti-IL12: 41.1 ± 2.4 mg/cm, p < 0.01) at a dose of 10 and 25 mg/kg, respectively. OPS-2071 suppressed TNF-α production in T cells, as well as macrophage activity in a dose-dependent fashion. OPS-2071 also suppressed human T-cell activation and proliferation. At high OPS-2071 concentrations, these effects were comparable to prednisolone. The minimum inhibitory concentration against IBD-related bacteria for: OPS-2071, ciprofloxacin, and metronidazole were 0.015–0.5, 0.25–8 and 0.03–>128 mg/ml, respectively. Conclusion OPS-2071 demonstrated significant therapeutic effect on colonic inflammation, suppressed TNF-α production in vitro and showed in vitro activity against bacteria related to CD. From these in vitro results, it can be concluded that OPS-2071 has anti-inflammatory activity, independent of its antibacterial activity. The dual effects demonstrated by this novel agent, OPS-2071, provided a rationale for exploring the impact of this compound on human CD in clinical trials.