inclusion criteria: 1. patients aged between 40 and 80 years 2. body weight between 50 kg and 100 kg 3. pcr diagnosis of sars-cov-2 virus infection 4. clinical diagnosis of severe lung involvement associated with sarscov- 2 virus infection according to the criteria of the national health commission of china, that is, patients who meet at least one of the following criteria: 1. respiratory distress with ≥ 30 breaths per minute; or 2. oxygen saturation ≤ 93% at baseline; or 3. partial arterial oxygen pressure (pao2) / fraction of inspiration of o2 (fio2) ≤300mmhg. (pao2 / fio2 is accepted based on sato2). patients who do not require respiratory support, or who require noninvasive respiratory support (conventional, high-flow oxygen therapy, or non-invasive mechanical ventilation) are considered eligible. 5. patients who are already receiving the standard medical treatment available for severe lung involvement associated with sars-cov-2 virus infection or any of the standard treatments are contraindicated in the patient and cannot be used and it is necessary to consider other alternatives. 6. women who are surgically sterile or postmenopausal or women of childbearing potential with negative urine or serum pregnancy test or men willing to use condoms for the entire duration of the study or for three months after the last dose of the investigational drug, whichever is later, or have a partner who is using a contraceptive method with high efficacy, such as described above. 7. signed informed consent.

inclusion criteria: 1. patients aged between 40 and 80 years 2. body weight between 50 kg and 100 kg 3. pcr diagnosis of sars-cov-2 virus infection 4. clinical diagnosis of severe lung involvement associated with sarscov- 2 virus infection according to the criteria of the national health commission of china, that is, patients who meet at least one of the following criteria: 1. respiratory distress with ≥ 30 breaths per minute; or 2. oxygen saturation ≤ 93% at baseline; or 3. partial arterial oxygen pressure (pao2) / fraction of inspiration of o2 (fio2) ≤300mmhg. (pao2 / fio2 is accepted based on sato2). patients who do not require respiratory support, or who require noninvasive respiratory support (conventional, high-flow oxygen therapy, or non-invasive mechanical ventilation) are considered eligible. 5. patients who are already receiving the standard medical treatment available for severe lung involvement associated with sars-cov-2 virus infection or any of the standard treatments are contraindicated in the patient and cannot be used and it is necessary to consider other alternatives. 6. women who are surgically sterile or postmenopausal or women of childbearing potential with negative urine or serum pregnancy test or men willing to use condoms for the entire duration of the study or for three months after the last dose of the investigational drug, whichever is later, or have a partner who is using a contraceptive method with high efficacy, such as described above. 7. signed informed consent.

inclusion criteria: patients aged between 40 and 80 years body weight between 50 kg and 100 kg pcr diagnosis of sars-cov-2 virus infection clinical diagnosis of severe lung involvement associated with sarscov- 2 virus infection according to the criteria of the national health commission of china, that is, patients who meet at least one of the following criteria: respiratory distress with ≥ 30 breaths per minute; or oxygen saturation ≤ 93% at baseline; or partial arterial oxygen pressure (pao2) / fraction of inspiration of o2 (fio2) ≤300mmhg. (pao2 / fio2 is accepted based on sato2). patients who do not require respiratory support, or who require noninvasive respiratory support (conventional, high-flow oxygen therapy, or non-invasive mechanical ventilation) are considered eligible. patients who are already receiving the standard medical treatment available for severe lung involvement associated with sars-cov-2 virus infection or any of the standard treatments are contraindicated in the patient and cannot be used and it is necessary to consider other alternatives. women who are surgically sterile or postmenopausal or women of childbearing potential with negative urine or serum pregnancy test or men willing to use condoms for the entire duration of the study or for three months after the last dose of the investigational drug, whichever is later, or have a partner who is using a contraceptive method with high efficacy, such as described above. signed informed consent.

inclusion criteria: patients aged between 40 and 80 years body weight between 50 kg and 100 kg pcr diagnosis of sars-cov-2 virus infection clinical diagnosis of severe lung involvement associated with sarscov- 2 virus infection according to the criteria of the national health commission of china, that is, patients who meet at least one of the following criteria: respiratory distress with ≥ 30 breaths per minute; or oxygen saturation ≤ 93% at baseline; or partial arterial oxygen pressure (pao2) / fraction of inspiration of o2 (fio2) ≤300mmhg. (pao2 / fio2 is accepted based on sato2). patients who do not require respiratory support, or who require noninvasive respiratory support (conventional, high-flow oxygen therapy, or non-invasive mechanical ventilation) are considered eligible. patients who are already receiving the standard medical treatment available for severe lung involvement associated with sars-cov-2 virus infection or any of the standard treatments are contraindicated in the patient and cannot be used and it is necessary to consider other alternatives. women who are surgically sterile or postmenopausal or women of childbearing potential with negative urine or serum pregnancy test or men willing to use condoms for the entire duration of the study or for three months after the last dose of the investigational drug, whichever is later, or have a partner who is using a contraceptive method with high efficacy, such as described above. signed informed consent.

inclusion criteria: 1. patients aged between 40 and 80 years 2. body weight between 50 kg and 100 kg 3. pcr diagnosis of sars-cov-2 virus infection 4. clinical diagnosis of severe lung involvement associated with sarscov- 2 virus infection according to the criteria of the national health commission of china, that is, patients who meet at least one of the following criteria: 1. respiratory distress with ≥ 30 breaths per minute; or 2. oxygen saturation ≤ 93% at baseline; or 3. partial arterial oxygen pressure (pao2) / fraction of inspiration of o2 (fio2) ≤300mmhg. (pao2 / fio2 is accepted based on sato2). patients who do not require respiratory support, or who require noninvasive respiratory support (conventional, high-flow oxygen therapy, or non-invasive mechanical ventilation) are considered eligible. 5. patients who are already receiving the standard medical treatment available for severe lung involvement associated with sars-cov-2 virus infection or any of the standard treatments are contraindicated in the patient and cannot be used and it is necessary to consider other alternatives. 6. women who are surgically sterile or postmenopausal or women of childbearing potential with negative urine or serum pregnancy test or men willing to use condoms for the entire duration of the study or for three months after the last dose of the investigational drug, whichever is later, or have a partner who is using a contraceptive method with high efficacy, such as described above. 7. signed informed consent.

inclusion criteria: 1. patients aged between 40 and 80 years 2. body weight between 50 kg and 100 kg 3. pcr diagnosis of sars-cov-2 virus infection 4. clinical diagnosis of severe lung involvement associated with sarscov- 2 virus infection according to the criteria of the national health commission of china, that is, patients who meet at least one of the following criteria: 1. respiratory distress with ≥ 30 breaths per minute; or 2. oxygen saturation ≤ 93% at baseline; or 3. partial arterial oxygen pressure (pao2) / fraction of inspiration of o2 (fio2) ≤300mmhg. (pao2 / fio2 is accepted based on sato2). patients who do not require respiratory support, or who require noninvasive respiratory support (conventional, high-flow oxygen therapy, or non-invasive mechanical ventilation) are considered eligible. 5. patients who are already receiving the standard medical treatment available for severe lung involvement associated with sars-cov-2 virus infection or any of the standard treatments are contraindicated in the patient and cannot be used and it is necessary to consider other alternatives. 6. women who are surgically sterile or postmenopausal or women of childbearing potential with negative urine or serum pregnancy test or men willing to use condoms for the entire duration of the study or for three months after the last dose of the investigational drug, whichever is later, or have a partner who is using a contraceptive method with high efficacy, such as described above. 7. signed informed consent.