Inclusion Criteria: 

• Signed Informed Consent Form by any patient capable of giving consent, or, when the patient is not capable of giving consent, by his or her legal/authorized
  representative.
• Age >/= 18 years at time of signing Informed Consent Form.
• Ability to comply with the study protocol, in the investigator's judgment.
• Hospitalized with COVID-19 pneumonia confirmed per WHO criteria (including a positive PCR of any specimen; e.g., respiratory, blood, urine, stool, other bodily
  fluid) and evidenced by chest X-ray or CT scan.
• SpO2
• For women of childbearing potential: agreement to remain abstinent (refrain from heterosexual intercourse) or use contraception, as defined below:
  • Women must remain abstinent or use contraceptive methods with a failure rate of < 1% per year during the treatment period and for 28 days after the final dose
    of TCZ.
  • A woman is considered to be of childbearing potential if she is postmenarchal, has not reached a postmenopausal state (>/= 12 continuous months of
    amenorrhea with no identified cause other than menopause), and is not permanently infertile due to surgery (i.e., removal of ovaries, fallopian tubes,
    and/or uterus) or another cause as determined by the investigator (e.g., Müllerian agenesis). The definition of childbearing potential may be
    adapted for alignment with local guidelines or regulations.
  • Examples of contraceptive methods with a failure rate of < 1% per year include bilateral tubal ligation, male sterilization, hormonal contraceptives that inhibit
    ovulation, hormone-releasing intrauterine devices, and copper intrauterine devices.
  • The reliability of sexual abstinence should be evaluated in relation to the duration of the clinical trial and the preferred and usual lifestyle of the patient.
    Periodic abstinence (e.g., calendar, ovulation, symptothermal, or postovulation methods) and withdrawal are not adequate methods of contraception.
    If required per local guidelines or regulations, locally recognized adequate methods of contraception and information about the reliability of abstinence will
    be described in the local Informed Consent Form.
• For men: agreement to remain abstinent (refrain from heterosexual intercourse) or use a condom, and agreement to refrain from donating sperm, as defined below:
  • With a female partner of childbearing potential or pregnant female partner, men must remain abstinent or use a condom during the treatment period and for 28
    days after the final dose of TCZ to avoid exposing the embryo. Men must refrain from donating sperm during this same period.
  • The reliability of sexual abstinence should be evaluated in relation to the duration of the clinical trial and the preferred and usual lifestyle of the patient.
    Periodic abstinence (e.g., calendar, ovulation, symptothermal, or postovulation methods) and withdrawal are not adequate methods of preventing drug
    exposure. If required per local guidelines or regulations, information about the reliability of abstinence will be described in the local Informed Consent Form.

Exclusion Criteria:

• Known severe allergic reactions to TCZ or other monoclonal antibodies.
• Active TB infection.
• Suspected active bacterial, fungal, viral, or other infection (besides COVID-19).
• In the opinion of the investigator, progression to death is imminent and inevitable within the next 24 hours, irrespective of the provision of treatments.
• Have received oral anti-rejection or immunomodulatory drugs (including TCZ) with the past 6 months.
• Participating in other drug clinical trials (participation in COVID-19 anti-viral trials may be permitted if approved by Medical Monitor).
• ALT or AST > 10 x ULN detected within 24 hours at screening or at baseline (according to local laboratory reference ranges).
• ANC < 1000/uL at screening and baseline (according to local laboratory reference ranges).
• Platelet count < 50,000/uL at screening and baseline (according to local laboratory reference ranges).
• Pregnant or breastfeeding, or positive pregnancy test in a pre-dose examination.
• Treatment with an investigational drug within 5 half-lives or 30 days (whichever is longer) of randomization (investigational COVID-19 antivirals may be permitted if approved by Medial Monitor).
• Any serious medical condition or abnormality of clinical laboratory tests that, in the investigator’s judgment, precludes the patient’s safe participation in and completion
  of the study.