Secondary Outcomes
Measure: Number of free days from invasive ventilation
Time: up to 21 days
Measure: Number of free days from non-invasive ventilation (NIV)
Time: up to 21 days
Measure: Change from baseline in PaO2/FiO2 ratio measured at 6 hours and 12 hours following administration of each dose in the treated group and at the similar timepoints in the control group
Time: 6, 12, 30, 36, 54 and 60 hours after randomisation
Measure: Change from baseline in PaO2/FiO2 ratio at additional timepoints
Time: every 24 hours after treatment/randomisation until the patient is discharged from the ICU . Up to 28 days
Measure: Length of ICU stay (days)
Time: up to 28 days
Measure: Mortality at Day 28
Time: Day 28
Measure: Change from baseline in ventilatory parameter (Tidal volume (TV))
Time: up to 28 days
Description: min score 0 max score 24
Measure: Delta Sequential Organ Failure Assessment (SOFA) Score
Time: up to 28 days
Measure: Incidence of all the AEs, AEs related to poractant alfa (treated cohort) (ADRs), serious AEs (SAEs) and AEs leading to death
Time: up to 28 days
Measure: Change from baseline in blood gas analysis acid-base balance parameter (pH)
Time: up to 28 days
Measure: Percentage of patients with PaO2/ FiO2 improvement of >20% following administration of each dose in the treated group and at similar timepoints in the control group
Time: at 6 and 12 hours following administration each dose in the treated group and at similar timepoints in the control group = up to 60 hours after the randomization
Measure: Number of Extracorporeal Membrane Oxygenation (ECMO)-free days- (only for cohort 2 of patients in ECMO)
Time: 21 days after randomization
Measure: Change from baseline in FiO2
Time: (6, 12, 30, 36, 54 and 60 hours after randomisation + every 24 hours after treatment/randomisation until the patient is discharged from the ICU = up to 28 days
Measure: Change from baseline in ventilatory parameter (respiratory rate (RR))
Time: up to 28 days
Measure: Change from baseline in ventilatory parameter (dynamic compliance (Cdyn))
Time: up to 28 days
Measure: Change from baseline in ventilatory parameter (static compliance (Cstat))
Time: up to 28 days
Measure: Change from baseline in ventilatory parameter (positive end-expiratory pressure (PEEP)
Time: up to 28 days
Measure: Change from baseline in ventilatory parameter (peak inspiratory pressure (PIP))
Time: up to 28 days
Measure: Change from baseline in ventilatory parameter (plateau pressure (Pplat))
Time: up to 28 days
Measure: Change from baseline in blood gas analysis acid-base balance parameter (pCO2)
Time: up to 28 days
Measure: Change from baseline in blood gas analysis acid-base balance parameter (pO2)
Time: up to 28 days
Measure: Change from baseline in blood gas analysis acid-base balance parameter (HCO3)
Time: up to 28 days
Measure: Change from baseline in blood gas analysis acid-base balance parameter (lactate)
Time: up to 28 days