This is a single-arm, open-label study to assess the pharmacokinetics, pharmacodynamics, safety, and exploratory efficacy of tocilizumab (TCZ) for the treatment of pediatric patients from birth to less than 18 years old hospitalized with COVID-19 and who are receiving systemic corticosteroids and require supplemental oxygen or mechanical ventilation.

Inclusion Criteria:

• Hospitalized with COVID-19 confirmed per a positive PCR of any specimen (e.g., respiratory, blood, urine, stool, or other bodily fluid) and evidenced by chest x-ray or CT scan
• Receiving systemic corticosteroids at baseline
• Oxygen saturation < 93% on room air, or requiring supplemental oxygen, non-invasive or invasive mechanical ventilation, or extracorporeal membrane oxygenation (ECMO) to maintain oxygen saturation > 92% at screening and baseline

Exclusion Criteria:

• Gestational age < 37 weeks
• Known severe allergic reactions to TCZ or other monoclonal antibodies
• Active tuberculosis infection
• Uncontrolled active bacterial, fungal, viral, or other infection (besides COVID-19)
• Diagnosis or suspected diagnosis of multisystem inflammatory syndrome in children (MIS-C)
• In the opinion of the investigator, progression to death is imminent and inevitable within the next 48 hours, irrespective of the provision of treatments
• Have received oral anti-rejection or immunomodulatory drugs (including TCZ) within the past 3 months prior to enrollment
• Treatment with an investigational drug within 5 drug-elimination half-lives or 30 days, whichever is longer, of enrollment (except for anti-SARS-CoV-2 antibodies or directly-acting antivirals)
• Participating in another interventional drug clinical trial (except for anti-SARS-CoV-2 antibodies or directly-acting antivirals)

Qualified researchers may request access to individual patient level data through the clinical study data request platform (www.vivli.org). Further details on Roche's criteria for eligible studies are available here (https://vivli.org/ourmember/roche/). For further details on Roche's Global Policy on the Sharing of Clinical Information and how to request access to related clinical study documents, see here (https://www.roche.com/research\_and\_development/who\_we\_are\_how\_we\_work/clinical\_trials/our\_commitment\_to\_data\_sharing.htm).