1) Hospitalised adult (≥16 yrs) patients with a laboratory-confirmed diagnosis of SARS-CoV-2 pneumonia (confirmed by reverse transcription polymerase chain reaction [RT-PCR] assay and chest X-ray) 2) Oxygen saturation (SaO2) of ≤94% while breathing ambient air or a ratio of the partial pressure of Oxygen (PaO2) to the fraction of inspired oxygen (FiO2) (PaO2:FiO2) ≤ 300 mg Hg (≤40kPa) Arm 2: Usual Care + Gemtuzumab Ozogamicin) Specific Inclusion Crieria The following criterion will apply until at least 3 patients have been allocated the IMP: 3) intubated and requiring mechanical ventilation

1) Hospitalised adult (≥16 yrs) patients with a laboratory-confirmed diagnosis of SARS-CoV-2 pneumonia (confirmed by reverse transcription polymerase chain reaction [RT-PCR] assay and chest X-ray) 2) Oxygen saturation (SaO2) of ≤94% while breathing ambient air or a ratio of the partial pressure of Oxygen (PaO2) to the fraction of inspired oxygen (FiO2) (PaO2:FiO2) ≤ 300 mg Hg (≤40kPa) Arm 2: Usual Care + Gemtuzumab Ozogamicin) Specific Inclusion Crieria The following criterion will apply until at least 3 patients have been allocated the IMP: 3) intubated and requiring mechanical ventilation