Infliximab for induction and maintenance therapy for ulcerative colitis

The anti-inflammatory drug dimethyl itaconate protects against colitis-associated colorectal cancer

Colorectal cancer (CRC) is the third most common diagnosed cancer of which risk factors include unhealthy diet, smoking, and chronic inflammation. Weakening the inflammatory response emerges as an effective therapeutic strategy to prevent the progression of CRC. Inflammatory macrophages produce substantial amounts of immunoregulatory metabolite itaconate, which is synthesized by the immune response gene 1 (Irg1). In this study, we use a membrane-permeable itaconate derivative, dimethyl itaconate (DI), for the protection against CRC in mouse model. DI decreased the high inflammatory state of ulcerative colitis and reduced the colitis-associated cancer (CAC) risk. Mechanistically, DI inhibited the secretion of the cytokines IL-1β and CCL2 from intestinal epithelial cells, and therefore reduced the recruitment of macrophages into tumor microenvironment. Meanwhile, the decrease of macrophage infiltration was accompanied by a decrease of myeloid-derived suppressor cell (MDSC) infiltration and the differentiation of T cell subsets into cytotoxic T cells. We showed that itaconate derivative limits inflammatory response, indicating a negative feedback loop that involves an inflammatory agent and itaconate. Our findings demonstrate the potential application of DI for the prevention of colitis-associated CRC. KEY MESSAGES: Dimethyl itaconate (DI) suppresses ulcerative colitis and colitis-associated colorectal cancer DI decreases infiltration of macrophages and myeloid-derived suppressor cells into tumor DI weakens the inflammatory response via inhibiting the secretion of IL-1β and CCL2.

Accelerated Clearance of Infliximab is Associated With Treatment Failure in Patients With Corticosteroid-Refractory Acute Ulcerative Colitis

BACKGROUND AND AIMS

A significant proportion of patients with corticosteroid-refractory acute ulcerative colitis [UC] fail therapy. We aimed to assess the pharmacokinetics [PK] of infliximab [IFX] in patients with corticosteroid-refractory acute UC and determine the association between induction IFX PK and short- and long-term therapy outcome.

METHODS

A population PK model was developed using data from 51 patients with UC [n = 42] and Crohn's disease [n = 9]. A subset of patients [n = 36] with acute corticosteroid-refractory UC (median Mayo score 11 [range 8-12]; 33 of 36 hospitalized; median corticosteroid dose at study entry 50mg prednisolone equivalent IV/oral) commencing IFX were studied to assess further correlations between PK from the first induction dose and therapy outcomes. Serial induction drug levels from the 36 UC patients were collected, facilitating population-based PK analysis. IFX and antibodies-to-infliximab [ATIs] concentrations were determined using AnsrTM IFX assay [Prometheus Inc.].

RESULTS

The Week 14 clinical response and Week 54 corticosteroid-free remission rates were 78% [28/36] and 53% [19/36], respectively. The estimated effective IFX half-life [T1/2] (median [range]) and clearance (median [range]) were 8.42 [3.94-22.03] days and 0.50 [0.19-1.41] L/day respectively. Longer induction IFX T1/2 and lower clearance were associated with the Week 14 clinical response [p = 0.005] and the Week 54 corticosteroid-free remission rates [p = 0.007].

CONCLUSIONS

Accelerated IFX clearance occurs in corticosteroid-refractory acute UC and is associated with therapy failure. These data support the use of accelerated IFX induction regimens in patients with corticosteroid-refractory acute UC failing conventional dosing regimens.

Tumor necrosis factor blockade: mechanism of action

Modulation of the immune response with tumor necrosis factor (TNF) blockers is not a new treatment strategy for many inflammatory disorders; however, relatively little is known about their specific mechanism of action. Understanding the mode of action, pharmacology, and pharmacokinetics of the monoclonal TNF antibodies, infliximab and adalimumab, and the soluble TNF receptor, etanercept, may therefore enable us to account for their differing clinical profiles. The aim of this supplement is to explore the roles and mechanisms of TNF and TNF blockade using in vitro pharmacological and in vivo animal modeling experiments, and in vivo studies of the effects of etanercept on the inflammatory cascade in patients with psoriasis.