THE ORAL GLUTMATE CARBOXYPEPTIDASE II INHIBITOR (S)-IBD3540 ROBUSTLY ATTENUATES INFLAMMATION IN SPONTANEOUS IL10 COLITIS

Abstract

Abstract BACKGROUND & AIMS Glutamate carboxypeptidase II (GCPII) is elevated in active inflamed biopsies of both Crohn’s disease and ulcerative colitis patients and is a promising therapeutic target for the treatment of IBD. We have previously presented the development and characterization of a first-in-class, gut-restricted, and orally active GCPII inhibitor, (S)-IBD3540, and have shown that oral (S)-IBD3540 attenuates disease severity in multiple murine colitis models, including acute dextran sulfate sodium (DSS)-induced colitis. Here, we extend our knowledge regarding (S)-IBD3540’s anti-inflammatory effects in spontaneously occurring colitis of interleukin 10 (IL10-/-) mice by performing longitudinal measurement of inflammatory biomarker fecal lipocalin 2 (LCN2) and terminal colon cytokine and chemokine measurements. METHODS Female BALB/cAnNTac-Il10em7Tac mice (Taconic, Germantown, NY) were acquired at 4 weeks of age and monitored three times weekly for the onset of clinical signs, including alterations in stool consistency. Following onset of symptoms, groups were randomized and treatment was initiated with vehicle or 100 mg/kg eq. (S)-IBD3540 once daily by oral gavage. Prior to treatment, and biweekly thereafter, fecal LCN2 was quantified using a mouse Lipocalin-2/NGAL DuoSet ELISA (R&D Systems). Upon study termination, proximal colon homogenates were prepared and analyzed by a mouse Cytokine/Chemokine 31-Plex Discovery Assay Array (Eve Technologies). RESULTS Impressively, despite initiating treatment in highly symptomatic mice 100 mg/kg oral (S)-IBD3540 was found to reverse abnormalities in stool consistency. Additionally, (S)-IBD3540 had potent anti-inflammatory effects. As expected, fecal LCN2 was observed to increase throughout the study period in vehicle treated mice, however, fecal LCN2 was significantly decreased in (S)-IBD3540 treated mice (p<0.05). Similarly, colon multiplex analysis identified significant reductions in multiple cytokines and chemokines implicated in IL10 colitis pathobiology, with notable reductions in cytokines TNFa, IL-12p40, and IL-17, and chemokines IP-10 and MIP-2. CONCLUSION (S)-IBD3540 is a novel, gut-restricted, GCPII inhibitor that has robust anti-inflammatory activity in IL10-/- colitis. Encouragingly, we have now found that in this model (S)-IBD3540 reduces pro-inflammatory cytokines/chemokines that are the targets of existing IBD medications. Studies to compare efficacy to one of these agents, anti-IL-12p40, are in progress.