Recombinant Human C1 Esterase Inhibitor (Ruconest®) in the Prevention of Severe SARS-CoV-2 Infection in Hospitalized Patients With COVID-19: a Randomized, Parallel-group, Open-label, Multi-center Pilot Trial in the United States (PROTECT-COVID-19-US)


The primary purpose of this study is to evaluate if adding rhC1-INH to standard of care (SOC) in patients admitted for stage II COVID-19 infection may reduce the risk of disease progression, i.e. ALI requiring mechanical ventilation, or increase the chance of a faster clinical improvement compared to SOC alone.


  • Age 18-85 years,
  • Admitted to the hospital because of confirmed positive SARS-CoV-2 (COVID-19 infection).
  • Evidence of pulmonary involvement on CT scan or X-Ray of the chest,
  • Symptom onset within the previous 10 days AND at least one additional risk factor for progression to mechanical ventilation: 1) arterial hypertension, 2) >50 years, 3) obesity (BMI>30.0 kg/m2), 4) history of cardiovascular disease, 5) chronic pulmonary disease, 7) chronic renal disease, 6) C-reactive protein of >35mg/L, 7) oxygen saturation at rest in ambient air of <94%