Novel prostaglandin D synthase inhibitors generated by fragment-based drug design.

We describe the discovery of novel inhibitors of prostaglandin D2 synthase (PGDS) through fragment-based lead generation and structure-based drug design. A library of 2500 low-molecular-weight compounds was screened using 2D nuclear magnetic resonance (NMR), leading to the identification of 24 primary hits. Structure determination of protein-ligand complexes with the hits enabled a hit optimization process, whereby we harvested increasingly more potent inhibitors out of our corporate compound collection. Two iterative cycles were carried out, comprising NMR screening, molecular modeling, X-ray crystallography, and in vitro biochemical testing. Six novel high-resolution PGDS complex structures were determined, and 300 hit analogues were tested. This rational drug design procedure culminated in the discovery of 24 compounds with an IC 50 below 1 microM in the in vitro assay. The best inhibitor (IC 50 = 21 nM) is one of the most potent inhibitors of PGDS to date. As such, it may enable new functional in vivo studies of PGDS and the prostaglandin metabolism pathway.

A novel IgE-neutralizing antibody for the treatment of severe uncontrolled asthma.

The critical role played by IgE in allergic asthma is well-documented and clinically precedented, but some patients in whom IgE neutralization may still offer clinical benefit are excluded from treatment with the existing anti-IgE therapy, omalizumab, due to high total IgE levels or body mass. In this study, we sought to generate a novel high affinity anti-IgE antibody (MEDI4212) with potential to treat a broad severe asthma patient population. Analysis of body mass, total and allergen-specific IgE levels in a cohort of severe asthmatics was used to support the rationale for development of a high affinity IgE-targeted antibody therapeutic. Phage display technology was used to generate a human IgG1 lead antibody, MEDI4212, which was characterized in vitro using binding, signaling and functional assay systems. Protein crystallography was used to determine the details of the interaction between MEDI4212 and IgE. MEDI4212 bound human IgE with an affinity of 1.95 pM and was shown to target critical residues in the IgE Cε3 domain critical for interaction with FcεRI. MEDI4212 potently inhibited responses through FcεRI and also prevented the binding of IgE to CD23. When used ex vivo at identical concentration, MEDI4212 depleted free-IgE from human sera to levels ~1 log lower than omalizumab. Our results thus indicate that MEDI4212 is a novel, high affinity antibody that binds specifically to IgE and prevents IgE binding to its receptors. MEDI4212 effectively depleted free-IgE from human sera ex vivo to a level (1 IU/mL) anticipated to provide optimal IgE suppression in severe asthma patients.

Identification of patients with chronic obstructive pulmonary disease (COPD) by measurement of plasma biomarkers.

INTRODUCTION: Inflammation is an important constituent of the pathology of chronic obstructive pulmonary disease (COPD), leading to alveolar destruction and airway remodelling. OBJECTIVE: The aim of this study was to assess the difference in plasma biomarkers of inflammation between asymptomatic smokers and patients with COPD. METHODS: We used commercially available enzyme-linked immunosorbent assay kits to measure the plasma levels of tumour necrosis factor-alpha (TNF-alpha), interleukin-8 (IL-8), matrix metalloproteinase-9 (MMP-9), monocyte chemotactic protein-1 (MCP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1) and tissue inhibitor of metalloproteinase-2 (TIMP-2) on two occasions with a 2-week interval in patients with COPD (n = 20), asymptomatic smokers (n = 10) and healthy lifelong non-smokers (n = 10). The participants were characterised clinically, physiologically and by quantitative computed tomography by measuring the relative area of emphysema below -910 Hounsfield units (RA-910). RESULTS: The results of the biomarker measurements on the two occasions were highly reproducible. Patients with COPD had significantly higher plasma levels of IL-8 (P = 0.004) and significantly lower levels of TIMP-1 (P = 0.02) than smokers and non-smokers. There was no statistically significant difference between the three groups in the level of TNF-alpha, MMP-9, MCP-1 and TIMP-2. The IL-8/TIMP-1 ratio correlated significantly with the degree of airway obstruction measured as forced expiratory volume in 1 second (FEV(1)) % predicted (r = -0.47, P < 0.01); with the diffusion capacity (r = -0.41, P < 0.01); and with the grade of emphysema measured as RA-910 (r = 0.39, P = 0.01). CONCLUSION: These findings suggest that the measurement of plasma biomarkers, such as IL-8/TIMP-1, may aid to discriminate patients with COPD from smokers at lower risk of developing COPD.

Cooperative inhibitory effects of budesonide and formoterol on eosinophil superoxide production stimulated by bronchial epithelial cell conditioned medium.

BACKGROUND: Improved asthma control by combinations of inhaled glucocorticosteroids (GCs) and long-acting beta(2)-agonists (LABAs) includes a reduced frequency and severity of exacerbations. In view of the association of exacerbations with increased airway inflammation, the question has arisen as to whether LABAs are able to complement the known anti-inflammatory activity of GCs. To address this, we studied the effects of a LABA, formoterol (FORM), and a GC, budesonide (BUD), alone and in combination, on bronchial epithelial cell-mediated eosinophil superoxide production in vitro. METHODS: We employed 2 experimental approaches. First, superoxide production by human eosinophils incubated with conditioned medium (CM) from human bronchial epithelial cells cultured for 24 h with vehicle, BUD, FORM or BUD + FORM was measured (Epi/Eos assay). Second, eosinophils were stimulated with vehicle-CM to which the drugs were added (Eos assay). Superoxide production was determined as the superoxide dismutase-inhibitable reduction of ferricytochrome C. RESULTS: CM increased eosinophil superoxide generation (p < 0.01) and epithelial-derived granulocyte macrophage colony-stimulating factor was the mediator responsible. In both assays, FORM dose-dependently inhibited eosinophil superoxide similarly and in the same concentration range as BUD. The BUD + FORM combination was more effective than BUD alone, and it completely inhibited CM-induced superoxide production in the Epi/Eos assay, suggesting complementary effects of both drugs on bronchial epithelial cells and eosinophils. CONCLUSIONS: The cooperative, inhibitory effects of BUD and FORM on eosinophils and bronchial epithelial cells, in terms of their effects on eosinophil superoxide production, may represent a possible mechanism for the enhanced anti-inflammatory efficacy of BUD and FORM combination therapy of asthma.