* known hypersensitivity to ati-450 * history or evidence of active or latent tuberculosis or recent exposure (within last 30d) to a person with active tb * evidence of active, untreated bacterial infection. patients who are treated with antibiotics for at least 72 hours, will become eligible for rescreening for trial enrollment * active use of immunosuppressant medication(s) (i.e. anti-rejection ,immunomodulators or immunosuppressant drugs, including but not limited to il-6 inhibitors, tnf inhibitors, anti-il-1 agents and janus kinase (jak) inhibitors within 5 half-lives or 30 days (whichever is longer) prior to randomization. (use of hydroxychloroquine/chloroquine should be discontinued) * oncology patients who are on active chemotherapy or immunotherapy. however, oncology patients who come off active therapy prior to enrollment and have absolute neutrophil count (anc) ≥1500/mmc are eligible for enrollment * active participation in a concurrent covid-19 clinical trial with investigative medical drug therapies. however, co-enrollment for non-investigative drug therapies will be allowed; use or re-purposing of fda approved treatments will be considered at the discretion of the medical monitor * in the opinion of the investigator, unlikely to survive for at least 48 hours from screening or anticipate mechanical ventilation within 48 hours * pregnancy or breast feeding * prisoner * intubation and ventilation at time of enrollment * known history for hiv, hepatitis b or c infection. patients with serologic evidence of hepatitis b vaccination (hepatitis b surface antibody without the presence of hepatitis b surface antigen) will be allowed to participate * history of a past or current medical condition that in the opinion of the treating physician would compromise patient safety (e.g. uncontrolled hiv) by participation in the study

* known hypersensitivity to ati-450 * history or evidence of active or latent tuberculosis or recent exposure (within last 30d) to a person with active tb * evidence of active, untreated bacterial infection. patients who are treated with antibiotics for at least 72 hours, will become eligible for rescreening for trial enrollment * active use of immunosuppressant medication(s) (i.e. anti-rejection ,immunomodulators or immunosuppressant drugs, including but not limited to il-6 inhibitors, tnf inhibitors, anti-il-1 agents and janus kinase (jak) inhibitors within 5 half-lives or 30 days (whichever is longer) prior to randomization. (use of hydroxychloroquine/chloroquine should be discontinued) * oncology patients who are on active chemotherapy or immunotherapy. however, oncology patients who come off active therapy prior to enrollment and have absolute neutrophil count (anc) ≥1500/mmc are eligible for enrollment * active participation in a concurrent covid-19 clinical trial with investigative medical drug therapies. however, co-enrollment for non-investigative drug therapies will be allowed; use or re-purposing of fda approved treatments will be considered at the discretion of the medical monitor * in the opinion of the investigator, unlikely to survive for at least 48 hours from screening or anticipate mechanical ventilation within 48 hours * pregnancy or breast feeding * prisoner * intubation and ventilation at time of enrollment * known history for hiv, hepatitis b or c infection. patients with serologic evidence of hepatitis b vaccination (hepatitis b surface antibody without the presence of hepatitis b surface antigen) will be allowed to participate * history of a past or current medical condition that in the opinion of the treating physician would compromise patient safety (e.g. uncontrolled hiv) by participation in the study

- known hypersensitivity to ati-450 - history or evidence of active or latent tuberculosis or recent exposure (within last 30d) to a person with active tb - evidence of active, untreated bacterial infection. patients who are treated with antibiotics for at least 72 hours, will become eligible for rescreening for trial enrollment - active use of immunosuppressant medication(s) (i.e. anti-rejection ,immunomodulators or immunosuppressant drugs, including but not limited to il-6 inhibitors, tnf inhibitors, anti-il-1 agents and janus kinase (jak) inhibitors within 5 half-lives or 30 days (whichever is longer) prior to randomization. (use of hydroxychloroquine/chloroquine should be discontinued) - oncology patients who are on active chemotherapy or immunotherapy. however, oncology patients who come off active therapy prior to enrollment and have absolute neutrophil count (anc) ≥1500/mmc are eligible for enrollment - active participation in a concurrent covid-19 clinical trial with investigative medical drug therapies. however, co-enrollment for non-investigative drug therapies will be allowed; use or re-purposing of fda approved treatments will be considered at the discretion of the medical monitor - in the opinion of the investigator, unlikely to survive for at least 48 hours from screening or anticipate mechanical ventilation within 48 hours - pregnancy or breast feeding - prisoner - intubation and ventilation at time of enrollment - known history for hiv, hepatitis b or c infection. patients with serologic evidence of hepatitis b vaccination (hepatitis b surface antibody without the presence of hepatitis b surface antigen) will be allowed to participate - history of a past or current medical condition that in the opinion of the treating physician would compromise patient safety (e.g. uncontrolled hiv) by participation in the study

- known hypersensitivity to ati-450 - history or evidence of active or latent tuberculosis or recent exposure (within last 30d) to a person with active tb - evidence of active, untreated bacterial infection. patients who are treated with antibiotics for at least 72 hours, will become eligible for rescreening for trial enrollment - active use of immunosuppressant medication(s) (i.e. anti-rejection ,immunomodulators or immunosuppressant drugs, including but not limited to il-6 inhibitors, tnf inhibitors, anti-il-1 agents and janus kinase (jak) inhibitors within 5 half-lives or 30 days (whichever is longer) prior to randomization. (use of hydroxychloroquine/chloroquine should be discontinued) - oncology patients who are on active chemotherapy or immunotherapy. however, oncology patients who come off active therapy prior to enrollment and have absolute neutrophil count (anc) ≥1500/mmc are eligible for enrollment - active participation in a concurrent covid-19 clinical trial with investigative medical drug therapies. however, co-enrollment for non-investigative drug therapies will be allowed; use or re-purposing of fda approved treatments will be considered at the discretion of the medical monitor - in the opinion of the investigator, unlikely to survive for at least 48 hours from screening or anticipate mechanical ventilation within 48 hours - pregnancy or breast feeding - prisoner - intubation and ventilation at time of enrollment - known history for hiv, hepatitis b or c infection. patients with serologic evidence of hepatitis b vaccination (hepatitis b surface antibody without the presence of hepatitis b surface antigen) will be allowed to participate - history of a past or current medical condition that in the opinion of the treating physician would compromise patient safety (e.g. uncontrolled hiv) by participation in the study