This study (EMPACTA) will a) evaluate the efficacy and safety of tocilizumab (TCZ) compared with a placebo in combination with standard of care (SOC) in hospitalized participants with COVID-19 pneumonia, and b) include an optional long-term extension for eligible participants to explore the long-term sequelae of resolved COVID-19 pneumonia.

Inclusion Criteria

• Hospitalized
• COVID-19 pneumonia confirmed by a positive polymerase chain reaction (PCR) of any specimen and radiographic imaging
• SpO2 < 94% while on ambient air

Inclusion Criteria Specific to Long-Term Extension

• Participated in Study ML42528 (EMPACTA) (includes participants who completed or discontinued early from the main study)

Exclusion Criteria

• Known severe allergic reactions to TCZ or other monoclonal antibodies
• Require continuous positive airway pressure (CPAP), bilevel positive airway pressure (BIPAP), or invasive mechanical ventilation
• 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
• Immunocompromised (besides well-controlled HIV) or on immunosuppressive therapy (except for steroids for COVID), advanced cancer
• Have received oral anti-rejection or immunomodulatory drugs (including TCZ) within the past 3 months
• Participating in another interleukin (IL)-6 antagonist clinical trial or other drug clinical trials (participation in COVID-19 anti-viral trials may be permitted if approved by Medical Monitor)
• Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) > 10 x upper limit of normal (ULN) detected within 24 hours at screening (according to local laboratory reference ranges)
• Absolute neutrophil count (ANC) < 1000/uL at screening (according to local laboratory reference ranges)
• Platelet count < 50,000/uL at screening (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 Medical 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
• Any history of Diverticulitis or GI perforation
• Use of systemic corticosteroids unless on a stable chronic dose

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).