GM-CSF Inhalation to Prevent ARDS in COVID-19 Pneumonia

Inclusion Criteria: 1. Signed informed consent form by the patient according to local regulations 2. Man or non-pregnant woman 3. Age ≥18 years 4. Willingness of patients with reproductive potential to use highly effective contraceptive methods by practicing abstinence or by using at least two methods of birth control from the date of consent to the end of the study. If abstinence could not be practiced, a combination of hormonal contraceptive (oral, injectable, or implants) and a barrier method (condom, diaphragm with a vaginal spermicidal agent) has to be used \*. 5. Lab-confirmed COVID-19 pneumonia where pneumonia is diagnosed by radiographic infiltrates by imaging (chest x-ray, CT scan, etc.), OR clinical assessment (evidence of rales/crackles on exam) AND pulse oximeter oxygen saturation ≤ 94% at room air in patients that do not have chronic hypoxia; or less than their baseline oxygenation in patients that suffer from chronic hypoxia 6. Negative serum pregnancy test in women of childbearing potentia Exclusion Criteria: 1. Pregnancy or breast feeding 2. Autoimmune thrombocytopenia, myelodysplastic syndromes with \> 20% marrow blast cells 3. History or presence of hypersensitivity or idiosyncratic reaction to molgramostim (e.g. Leucomax®) or to related compounds (e.g. Leukine®) 4. Patient not able to use nebulizer device as well as immediately foreseeable mechanical ventilation of the patient 5. Simultaneous participation in another clinical trial with an experimental treatment