In vitro activity: Alvelestat, also known as AZD9668, is an orally bioavailable, novel and highly selective inhibitor of neutrophil elastase (NE) with IC50 and Ki of 12 nM and 9.4 nM, it is at least 600-fold more selective over other serine proteases. Neutrophil elastase (NE) is an enzyme implicated in the signs, symptoms, and disease progression in NE-driven respiratory diseases such as bronchiectasis and chronic obstructive pulmonary disease via its role in the inflammatory process, mucus overproduction, and lung tissue damage. In cell-based assays, AZD9668 inhibited plasma NE activity in zymosan-stimulated whole blood. AZD9668 has the potential to reduce lung inflammation and the associated structural and functional changes in human diseases.

Kinase Assay: AZD9668 had a high binding affinity for human NE (KD = 9.5 nM) and potently inhibited NE activity. The calculated pIC50 (IC50) and Ki values for AZD9668 for human NE were 7.9 (12 nM) and 4.9 nM, respectively. In contrast to earlier NE inhibitors, the interaction between AZD9668 and NE was rapidly reversible. AZD9668 was also highly selective for NE over other neutrophil-derived serine proteases.

Cell Assay: In cell-based assays, AZD9668 inhibited plasma NE activity in zymosan-stimulated whole blood. In isolated human polymorphonuclear cells, AZD9668 inhibited NE activity on the surface of stimulated cells and in the supernatant of primed, stimulated cells.AZD9668 showed good crossover potency to NE from other species.