Background: The intensity of inflammation during COVID-19 is related to adverse outcomes. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is involved in low-density lipoprotein receptor homeostasis, with potential influence on vascular inflammation and on COVID-19 inflammatory response.

Objectives: The goal of this study was to investigate the impact of PCSK9 inhibition vs placebo on clinical and laboratory outcomes in patients with severe COVID-19.

Methods: In this double-blind, placebocontrolled, multicenter pilot trial, 60 patients hospitalized for severe COVID-19, with groundglass opacity pneumonia and arterial partial oxygen pressure to fraction of inspired oxygen ratio ≤300 mm Hg, were randomized 1:1 to receive a single 140-mg subcutaneous injection of evolocumab or placebo. The primary endpoint was death or need for intubation at 30 days. The main secondary endpoint was change in circulating interleukin (IL)-6 at 7 and 30 days from baseline.

Results: Patients randomized to receive the PCSK9 inhibitor had lower rates of death or need for intubation within 30 days vs placebo (23.3% vs 53.3%, risk difference: –30%; 95% CI: –53.40% to –6.59%). Serum IL-6 across time was lower with the PCSK9 inhibitor than with placebo (30-day decline: –56% vs –21%). Patients with baseline IL-6 above the median had lower mortality with PCSK9 inhibition vs placebo (risk difference: –37.50%; 95% CI:–68.20% to –6.70%).