1,2,4-Triazolo-[1,5‑<i>a</i>]pyridine HIF Prolylhydroxylase Domain‑1 (PHD-1) Inhibitors With a Novel Monodentate Binding Interaction

Herein we describe the identification of 4-{[1,2,4]­triazolo­[1,5-<i>a</i>]­pyridin-5-yl}­benzonitrile-based inhibitors of the hypoxia-inducible factor prolylhydroxylase domain-1 (PHD-1) enzyme. These inhibitors were shown to possess a novel binding mode by X-ray crystallography, in which the triazolo N1 atom coordinates in a hitherto unreported monodentate interaction with the active site Fe²⁺ ion, while the benzonitrile group accepts a hydrogen-bonding interaction from the side chain residue of Asn315. Further optimization led to potent PHD-1 inhibitors with good physicochemical and pharmacokinetic properties

The Discovery of Potent, Selective, and Reversible Inhibitors of the House Dust Mite Peptidase Allergen Der p 1: An Innovative Approach to the Treatment of Allergic Asthma

Blocking the bioactivity of allergens is conceptually attractive as a small-molecule therapy for allergic diseases but has not been attempted previously. Group 1 allergens of house dust mites (HDM) are meaningful targets in this quest because they are globally prevalent and clinically important triggers of allergic asthma. Group 1 HDM allergens are cysteine peptidases whose proteolytic activity triggers essential steps in the allergy cascade. Using the HDM allergen Der p 1 as an archetype for structure-based drug discovery, we have identified a series of novel, reversible inhibitors. Potency and selectivity were manipulated by optimizing drug interactions with enzyme binding pockets, while variation of terminal groups conferred the physicochemical and pharmacokinetic attributes required for inhaled delivery. Studies in animals challenged with the gamut of HDM allergens showed an attenuation of allergic responses by targeting just a single component, namely, Der p 1. Our findings suggest that these inhibitors may be used as novel therapies for allergic asthma