- Has respiratory rate >= 30 per minute, or heart rate ≥ 125 per minute at hospitalisation. - Has severe COVID-19 requiring non-invasive or invasive mechanical ventilation and/or intensive care. - Has ongoing clinically significant thromboembolic event, according to Investigator. - Has any other medical condition, which in the opinion of the Investigator, would impact the safety of the subjects. - Has received an investigational or approved vaccination against SARS-CoV-2 within 30 days before study treatment start. - Has known allergy or hypersensitivity reaction to any monoclonal antibody or to any components of study treatment. - For WOCBP: o Pregnancy or a positive urine pregnancy test o Breastfeeding Exclusion Criteria only Applicable to Part 1 - Has received or is receiving concomitant treatment with medicinal products with potential or demonstrated anti SARS CoV 2 (antiviral) activity, including but not limited to remdesivir, within 30 days prior to the study treatment administration. - Has morbid obesity (body mass index > 35 kg/m2), uncontrolled diabetes, cardiac insufficiency, uncontrolled high blood pressure, or any clinically significant (in the opinion of the Investigator) hepatic, pulmonary, gastrointestinal, genitourinary, endocrine, immunologic, metabolic, neurologic, or haematological disease.

- Has respiratory rate >= 30 per minute, or heart rate ≥ 125 per minute at hospitalisation. - Has severe COVID-19 requiring non-invasive or invasive mechanical ventilation and/or intensive care. - Has ongoing clinically significant thromboembolic event, according to Investigator. - Has any other medical condition, which in the opinion of the Investigator, would impact the safety of the subjects. - Has received an investigational or approved vaccination against SARS-CoV-2 within 30 days before study treatment start. - Has known allergy or hypersensitivity reaction to any monoclonal antibody or to any components of study treatment. - For WOCBP: o Pregnancy or a positive urine pregnancy test o Breastfeeding Exclusion Criteria only Applicable to Part 1 - Has received or is receiving concomitant treatment with medicinal products with potential or demonstrated anti SARS CoV 2 (antiviral) activity, including but not limited to remdesivir, within 30 days prior to the study treatment administration. - Has morbid obesity (body mass index > 35 kg/m2), uncontrolled diabetes, cardiac insufficiency, uncontrolled high blood pressure, or any clinically significant (in the opinion of the Investigator) hepatic, pulmonary, gastrointestinal, genitourinary, endocrine, immunologic, metabolic, neurologic, or haematological disease.