Recombinant Human Angiotensin-converting Enzyme 2 (rhACE2) as a Treatment for Patients With COVID-19

The primary endpoint was a composite endpoint of all cause-death or invasive mechanical ventilation up to 28 days or hospital discharge.

Log transformed levels of LDH at Day 5 as a surrogate marker for organ damage (powered secondary endpoint).

28-day mortality (all cause-death).

VFD up to 28 days or hospital discharge. VFD and mechanical-VFD (mVFD) were calculated as time in the study minus duration of ventilation and were set to zero if the duration of ventilation exceeded the time in the study.

Three analysis approaches were used: 1) Death not censored: (m)VFD was set to zero for patients who died. 2) Death censored: patients who died before or on Day 28 were censored at the day before death. 3) Alive patients analyzed: only patients who were alive at Day 28, hospital discharge, or early termination were included in the analysis.

Time to death (all causes).

The WHO Clinical Progression Scale provides a measure of illness severity across an 11 point range from 0 (not infected) to 10 (dead) as follows (scores 4-9 contain measures of respiratory failure):

Uninfected, no viral deoxyribonucleic acid (DNA) detected = 0;

Asymptomatic, viral DNA detected = 1;

Symptomatic, independent = 2;

Symptomatic, assistance needed = 3;

Hospitalized, no oxygen therapy = 4;

Hospitalized, oxygen by mask or nasal prongs = 5;

Hospitalized, oxygen by non-invasive ventilation (NIV) or high flow = 6;

Intubation and mechanical ventilation, partial pressure of oxygen (pO2)/fraction of inspired oxygen (FiO2)≥ 150 or oxygen saturation (SpO2)/FiO2≥200 = 7;

Mechanical ventilation, pO2/FiO2 < 150 (SpO2/FiO2 < 200) or vasopressors = 8;

Mechanical ventilation, pO2/FiO2 < 150 and vasopressors, dialysis, or extracorporeal membrane oxygenation (ECMO) = 9;

Dead = 10.

A decrease in the score reflects an improvement.

The number of days from randomization to discharge from hospital was calculated (Kaplan-Meier analysis).

Patients without hospitalization or without documented hospital discharge who completed the study or were early terminated before Day 28 were censored at the date of study completion or discontinuation, respectively.

Patients who died before Day 28 were censored at the date of death even if early terminated before.

Viral RNA was assessed in blood samples using quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and projected to RNA copies per mL.

The time from randomization to an at least 2-point decrease in the WHO scale was calculated. The WHO Clinical Progression Scale provides a measure of illness severity across an 11 point range from 0 (not infected) to 10 (dead) as follows (scores 4-9 contain measures of respiratory failure):

Uninfected, no viral DNA detected = 0;

Asymptomatic, viral DNA detected = 1;

Symptomatic, independent = 2;

Symptomatic, assistance needed = 3;

Hospitalized, no oxygen therapy = 4;

Hospitalized, oxygen by mask or nasal prongs = 5;

Hospitalized, oxygen by non-invasive ventilation (NIV) or high flow = 6;

Intubation and mechanical ventilation, pO2/FiO2 ≥ 150 or SpO2/FiO2≥200 = 7;

Mechanical ventilation, pO2/FiO2 < 150 (SpO2/FiO2 < 200) or vasopressors = 8;

Mechanical ventilation, pO2/FiO2 < 150 and vasopressors, dialysis, or ECMO = 9;

Dead = 10.

A decrease in the score reflects an improvement in disease status.

The number of patients receiving mechanical ventilation and supplemental oxygen was evaluated.

Time from randomization to first use of invasive mechanical ventilation was calculated (Kaplan-Meier analysis).

Patients without documented invasive mechanical ventilation who completed the study, were early terminated or discharged from hospital before Day 28 were censored at the date of study completion, discontinuation or discharge from hospital, respectively.

The ratio in partial pressure of arterial oxygen (PaO2)/fraction of inspired oxygen (FiO2) was assessed by analysis of patient's blood gas.

The mSOFA score predicts intensive care unit mortality using clinical and laboratory variables. 5 organ systems (respiratory SpO2/FiO2; liver; cardiovascular/hypotension; Central nervous System/Glasgow Coma Score; renal/creatinine), all, except for liver, scored on a 0 to 4 scale (liver: 2-point scale: 0 or 3) according to specified criteria indicating severity, with the total score ranging from 0 to a maximum score of 19. A higher score reflects a worse disease state.

Lymphocytes were assessed in blood samples from the patients.

C-reactive protein was assessed in blood samples from the patients.

D-Dimer was assessed in blood samples from the patients.

Log transformed levels of LDH in blood were assessed as a surrogate marker for organ damage.