Plerixafor in Acute Respiratory Distress Syndrome Related to COVID-19 (Phase IIb)

This phase IIb study, LEONARDO is a multicenter, randomized, double-blind, placebo- controlled, parallel group study, to assess the therapeutic efficacy and safety of Plerixafor in patients over 18 years of age, * with acute respiratory failure related to COVID-19 and * Recently admitted in ICU or equivalent structure (within 48 hours) for COVID-19 related respiratory failure * without invasive mechanical ventilation and * requiring oxygen support ≥ 5L/min to obtain a transcutaneous O2 saturation \> 94% A total of 150 participants, will be randomized in a 2:1 ratio to receive either Plerixafor (n=100) or placebo (n=50) as a continuous IV infusion for 7 days (from D1 to D8) in addition to standard of care (e.g. glucocorticoids...). Safety data will be reviewed by an independent Data and Safety Monitoring Board (DSMB) during the study.