Dipeptidyl Peptidase-1 Inhibition in Patients Hospitalized with COVID-19: a Multicentre Randomized Double-Blind Placebo Controlled Trial

Background: Neutrophil serine proteases (NSPs) are involved in the pathogenesis of COVID19 and are increased in severe and fatal infection. We investigated whether treatment with Brensocatib, an inhibitor of dipeptidyl peptidase-1, an enzyme responsible for the activation of NSPs, would improve outcomes in hospitalized patients with COVID19. Methods: In a randomized, double-blind, placebo-controlled trial, 406 hospitalized patients with COVID19 with at least one risk factor for severe disease were randomized 1:1 to once-daily Brensocatib 25mg (n=192) or placebo (n=214) for 28 days. Primary outcome was the 7-point World Health Organisation Clinical Status scale at day 29. Secondary outcomes included time to clinical improvement, national early warning score, new oxygen and ventilation use, neutrophil elastase activity in blood and mortality. Findings: Brensocatib treatment was associated with worse clinical status at day 29 (adjusted odds ratio 0·72, 95%CI 0·57-0·92) compared to placebo. The adjusted hazard ratio (aHR) for time to clinical improvement was 0·87 (95%CI 0·76-1·00) and time to hospital discharge was 0·98 (95%CI 0·84-1·13). During the 28-day follow-up period, 23 (11%) and 29 (15%) patients died in the placebo and Brensocatib treated groups respectively). Oxygen and new ventilation use were greater in the Brensocatib treated patients. Neutrophil elastase activity in blood was significantly reduced in the Brensocatib group from baseline to day 29. Prespecified subgroup analyses of the primary outcome supported the primary results. Interpretation: Brensocatib treatment did not improve day 29 clinical status in hospitalised patients with COVID19