Primary objective of the study is to evaluate the efficacy of Aprotinin as add-on therapy in patients hospitalized with COVID-19 using the following parameters:~The time to elimination of SARS-CoV-2 virus until Day 10;~The time to C-reactive protein (CRP) normalization until Day 10;~The time to D-dimer normalization until Day 10.~Secondary objectives are to evaluate the following parameters of efficacy and safety of Aprotinin add-on therapy in patients hospitalized with COVID-19:~The time to body temperature normalization (<37oC);~Changes from baseline of the laboratory parameters during 14 days: hematology, CRP, coagulogram;~Changes of lung injury on CT scan on Day 7 and Day 14 from baseline;~Frequency of clinical status improvement by 2 scores in accordance with the WHO Ordinal scale of clinical improvement (WHO-OSCI) or discharge from the hospital before Day 14;~Frequency of transfer to the Intensive Care Unit (ICU), frequency of the non-invasive ventilation, frequency of the invasive ventilation and mortality rate;~Frequency of Adverse Events (AEs) and Serious Adverse Events (SAEs) of various severity according to subjective complains, physical examination, vital signs, laboratory tests and ECG.
The observational study will be carried out in two stages. At the first stage, the efficacy and safety of Aprotinin intravenous infusion as add-on therapy to the standard of care will be studied. At the second stage, two groups will be included: the first group will be the inhaled Aprotinin add-on therapy, the second group will be intravenous Aprotinin in combination with Favipiravir.