Brensocatib (AZD7986) is a Dipeptidyl peptidase 1 (DPP1) inhibitor (pIC50s: 6.85, 7.7, 7.6, 7.8, and 7.8 in human, rat, mouse, rabbit, and dog, respectively).

DPP1:pIC50: 7.7(rat), DPP1:pIC50: 6.85(human), DPP1:pIC50: 7.8(rabbit), DPP1:pIC50: 7.6(mouse), DPP1:pIC50: 7.8(dog)

Activation of neutrophil serine proteases is assessed in vitro using primary bone marrow-derived CD34+ neutrophil progenitor cells. Cells are cultured in media supplemented with rhSCF and rhIL-3 for 7 days, and then for a further 7 days in the presence of G-CSF and different concentrations of AZD7986 (38 pM to 10 μM). After harvesting and lysis with 10% Triton X-100 buffer, cell lysates are kept at -20°C until NSP activity analysis.

Cellular potency is studied using the DPP1-expressing monocytic U937 cell line. Briefly, cells grown in RPMI are plated on 384-well polypropylene v-bottom plates at a density of 5×10^5 cells/mL per well. Added to this is 10 μL of AZD7986 at 37°C for 60 min, followed by 350 μM Gly-Phe-AFC. The well fluorescence is read using a multilabel plate reader. Data are analyzed to calculate pIC50 values.

Rats are used for the in vivo study. Naive rats are dosed orally twice daily with AZD7986 at 0.2, 2, and 20 mg/kg/day for 8 days. At termination, bone marrow is taken by femural aspiration for neutrophil serine proteases activity analysis using commercial synthetic peptide substrates.