inclusion criteria: * age ≥ 18 years (or above legal age, e.g. uk ≥16 years) * ards with pao2\*/fio2 ratio \>100 and ≤300, either on non-invasive ventilator support, or on mechanical ventilation (\<48 hours since intubation), * with bilateral opacities in chest x-ray or ct scan (not fully explained by effusions, lobar/lung collapse, or nodules) * with respiratory failure (not fully explained by cardiac failure/fluid overload) (\*or estimation of pao2/fio2 from pulse oximetry (spo2/fio2)) * sars-cov-2 positive (laboratory-confirmed reverse transcription polymerase chain reaction (rt pcr) test) * fibrinogen level ≥ lower limit of normal (according to local laboratory) * d-dimer ≥ upper limit of normal (uln) according to local laboratory * signed and dated written informed consent in accordance with ich good clinical practice (gcp) and local legislation prior to admission to the trial

inclusion criteria: * age ≥ 18 years (or above legal age, e.g. uk ≥16 years) * ards with pao2\*/fio2 ratio \>100 and ≤300, either on non-invasive ventilator support, or on mechanical ventilation (\<48 hours since intubation), * with bilateral opacities in chest x-ray or ct scan (not fully explained by effusions, lobar/lung collapse, or nodules) * with respiratory failure (not fully explained by cardiac failure/fluid overload) (\*or estimation of pao2/fio2 from pulse oximetry (spo2/fio2)) * sars-cov-2 positive (laboratory-confirmed reverse transcription polymerase chain reaction (rt pcr) test) * fibrinogen level ≥ lower limit of normal (according to local laboratory) * d-dimer ≥ upper limit of normal (uln) according to local laboratory * signed and dated written informed consent in accordance with ich good clinical practice (gcp) and local legislation prior to admission to the trial

inclusion criteria: age ≥ 18 years (or above legal age, e.g. uk ≥16 years) ards with pao2*/fio2 ratio >100 and ≤300, either on non-invasive ventilator support, or on mechanical ventilation (<48 hours since intubation), with bilateral opacities in chest x-ray or ct scan (not fully explained by effusions, lobar/lung collapse, or nodules) with respiratory failure (not fully explained by cardiac failure/fluid overload) (*or estimation of pao2/fio2 from pulse oximetry (spo2/fio2)) sars-cov-2 positive (laboratory-confirmed reverse transcription polymerase chain reaction (rt pcr) test) fibrinogen level ≥ lower limit of normal (according to local laboratory) d-dimer ≥ upper limit of normal (uln) according to local laboratory signed and dated written informed consent in accordance with ich good clinical practice (gcp) and local legislation prior to admission to the trial

inclusion criteria: age ≥ 18 years (or above legal age, e.g. uk ≥16 years) ards with pao2*/fio2 ratio >100 and ≤300, either on non-invasive ventilator support, or on mechanical ventilation (<48 hours since intubation), with bilateral opacities in chest x-ray or ct scan (not fully explained by effusions, lobar/lung collapse, or nodules) with respiratory failure (not fully explained by cardiac failure/fluid overload) (*or estimation of pao2/fio2 from pulse oximetry (spo2/fio2)) sars-cov-2 positive (laboratory-confirmed reverse transcription polymerase chain reaction (rt pcr) test) fibrinogen level ≥ lower limit of normal (according to local laboratory) d-dimer ≥ upper limit of normal (uln) according to local laboratory signed and dated written informed consent in accordance with ich good clinical practice (gcp) and local legislation prior to admission to the trial

inclusion criteria: - age ≥ 18 years (or above legal age, e.g. uk ≥16 years) - ards with pao2*/fio2 ratio >100 and ≤300, either on non-invasive ventilator support, or on mechanical ventilation (<48 hours since intubation), - with bilateral opacities in chest x-ray or ct scan (not fully explained by effusions, lobar/lung collapse, or nodules) - with respiratory failure (not fully explained by cardiac failure/fluid overload) (*or estimation of pao2/fio2 from pulse oximetry (spo2/fio2)) - sars-cov-2 positive (laboratory-confirmed reverse transcription polymerase chain reaction (rt pcr) test) - fibrinogen level ≥ upper limit of normal (according to local laboratory) - d-dimer ≥ 3-fold of upper limit of normal (uln) according to local laboratory - signed and dated written informed consent in accordance with ich good clinical practice (gcp) and local legislation prior to admission to the trial

inclusion criteria: - age ≥ 18 years (or above legal age, e.g. uk ≥16 years) - ards with pao2*/fio2 ratio >100 and ≤300, either on non-invasive ventilator support, or on mechanical ventilation (<48 hours since intubation), - with bilateral opacities in chest x-ray or ct scan (not fully explained by effusions, lobar/lung collapse, or nodules) - with respiratory failure (not fully explained by cardiac failure/fluid overload) (*or estimation of pao2/fio2 from pulse oximetry (spo2/fio2)) - sars-cov-2 positive (laboratory-confirmed reverse transcription polymerase chain reaction (rt pcr) test) - fibrinogen level ≥ upper limit of normal (according to local laboratory) - d-dimer ≥ 3-fold of upper limit of normal (uln) according to local laboratory - signed and dated written informed consent in accordance with ich good clinical practice (gcp) and local legislation prior to admission to the trial

inclusion criteria: - age ≥ 18 years (or above legal age, e.g. uk ≥16 years) - ards with pao2*/fio2 ratio >100 and ≤300, either on non-invasive ventilator support, or on mechanical ventilation (<48 hours since intubation), - with bilateral opacities in chest x-ray or ct scan (not fully explained by effusions, lobar/lung collapse, or nodules) - with respiratory failure (not fully explained by cardiac failure/fluid overload) (*or estimation of pao2/fio2 from pulse oximetry (spo2/fio2)) - sars-cov-2 positive (laboratory-confirmed rt pcr test) - fibrinogen level ≥ upper limit of normal (according to local laboratory) - d-dimer ≥ 3-fold of upper limit of normal (uln) according to local laboratory - signed and dated written informed consent in accordance with ich good clinical practice (gcp) and local legislation prior to admission to the trial

inclusion criteria: - age ≥ 18 years (or above legal age, e.g. uk ≥16 years) - ards with pao2*/fio2 ratio >100 and ≤300, either on non-invasive ventilator support, or on mechanical ventilation (<48 hours since intubation), - with bilateral opacities in chest x-ray or ct scan (not fully explained by effusions, lobar/lung collapse, or nodules) - with respiratory failure (not fully explained by cardiac failure/fluid overload) (*or estimation of pao2/fio2 from pulse oximetry (spo2/fio2)) - sars-cov-2 positive (laboratory-confirmed rt pcr test) - fibrinogen level ≥ upper limit of normal (according to local laboratory) - d-dimer ≥ 3-fold of upper limit of normal (uln) according to local laboratory - signed and dated written informed consent in accordance with ich good clinical practice (gcp) and local legislation prior to admission to the trial