respiratory rate greater than or equal to ≥20 breaths per minute. oxygen saturation by pulse oximetry less than or equal to ≤93 percent % on room air or requirement for supplemental oxygen to maintain oxygen saturation greater than >93 percent %. total news score greater than or equal to ≥6 or presence of a score of 3 on any of the individual news parameters. radiographic evidence of pulmonary infiltrates (clinical x-ray within 2 days of referral) hepatic profile showing any of the following: serum alanine aminotransferase (alt) greater than >5 × upper limit of normal (uln) (ctcae grade greater than or equal to ≥3). serum aspartate aminotransferase (ast) greater than >5 × uln (ctcae grade greater than or equal to ≥3). serum bilirubin greater than >1.5 × uln (ctcae grade greater than or equal to ≥2). renal profile showing an estimated creatinine clearance (eclcr) less than <30 ml/minute (with eclcr to be calculated by the method at the laboratory performing the serum creatinine test). presence of a cancer with disease manifestations or therapy that could adversely affect subject safety or longevity, create the potential for drug-drug interactions, or compromise the interpretation of study results. significant cardiovascular disease (e.g. myocardial infarction, arterial thromboembolism, cerebrovascular thromboembolism) within 1 month prior to start of study therapy; unstable angina; symptomatic peripheral vascular disease; ctcae grade greater than or equal to ≥2 congestive heart failure; or uncontrolled ctcae grade greater than or equal to ≥3 hypertension (diastolic blood pressure greater than or equal to ≥100 mmhg or systolic blood pressure greater than or equal to ≥160 mmhg) despite antihypertensive therapy. significant screening ecg abnormalities, including atrial fibrillation/flutter, 2nd degree atrioventricular (av) block type ii, 3rd-degree av block, grade greater than or equal to ≥2 bradycardia, or corrected qt (qtc by fridericia [qtcf]) greater than >480 msec (grade greater than >1). gastrointestinal disease (e.g. gastric or intestinal bypass surgery, pancreatic enzyme insufficiency, malabsorption syndrome, symptomatic inflammatory bowel disease, chronic diarrheal illness, bowel obstruction) that might interfere with drug absorption or with interpretation of gastrointestinal aes. pregnancy or breastfeeding. prior solid organ transplantation. use within 5 days prior to randomization of an approved or investigational therapy intended to treat covid-19 (e.g. remdesivir, , anti-interleukin [il]-6 antibodies, therapeutic anti-sars cov-2 antibodies or post-convalescent plasma, anti- sars cov-2 vaccine, bruton tyrosine kinase [btk] inhibitor), use within 3 months of chloroquine or hydroxychloroquine. note: participants are not precluded from undergoing evaluations involving observation, noninvasive diagnostic procedures or sampling, or questionnaires as follow-up to a prior study or as components of a concurrent noninterventional study. use within 5 days prior to randomization of a strong inhibitor or inducer of cytochrome p450 (cyp) 3a4 or expected requirement for chronic use of a strong inhibitor or inducer of cyp3a4 during study therapy. use within 5 days prior to randomization of drug that is a moderate-to-strong substrate of cyp2c9 (including warfarin, tolbutamide, phenytoin, glimepiride) or expected requirement for chronic use of such drugs during study therapy. use within 5 days prior to randomization of a drug known to prolong the qt interval ongoing immunosuppressive therapy including systemic or enteric corticosteroids. (note: at study entry, participants may be using intraarticular, inhaled, or topical corticosteroids. during study therapy, participants may use systemic, enteric, intraarticular, inhaled, or topical corticosteroids as required for intercurrent conditions.) any illness, medical condition, organ system dysfunction, or social situation, including mental illness or substance abuse, deemed by the investigator to be likely to interfere with a participant's ability to provide informed consent, adversely affect the participant's ability to cooperate and participate in the study, or compromise the interpretation of study results.

respiratory rate greater than or equal to ≥20 breaths per minute. oxygen saturation by pulse oximetry less than or equal to ≤93 percent % on room air or requirement for supplemental oxygen to maintain oxygen saturation greater than >93 percent %. total news score greater than or equal to ≥6 or presence of a score of 3 on any of the individual news parameters. radiographic evidence of pulmonary infiltrates (clinical x-ray within 2 days of referral) hepatic profile showing any of the following: serum alanine aminotransferase (alt) greater than >5 × upper limit of normal (uln) (ctcae grade greater than or equal to ≥3). serum aspartate aminotransferase (ast) greater than >5 × uln (ctcae grade greater than or equal to ≥3). serum bilirubin greater than >1.5 × uln (ctcae grade greater than or equal to ≥2). renal profile showing an estimated creatinine clearance (eclcr) less than <30 ml/minute (with eclcr to be calculated by the method at the laboratory performing the serum creatinine test). presence of a cancer with disease manifestations or therapy that could adversely affect subject safety or longevity, create the potential for drug-drug interactions, or compromise the interpretation of study results. significant cardiovascular disease (e.g. myocardial infarction, arterial thromboembolism, cerebrovascular thromboembolism) within 1 month prior to start of study therapy; unstable angina; symptomatic peripheral vascular disease; ctcae grade greater than or equal to ≥2 congestive heart failure; or uncontrolled ctcae grade greater than or equal to ≥3 hypertension (diastolic blood pressure greater than or equal to ≥100 mmhg or systolic blood pressure greater than or equal to ≥160 mmhg) despite antihypertensive therapy. significant screening ecg abnormalities, including atrial fibrillation/flutter, 2nd degree atrioventricular (av) block type ii, 3rd-degree av block, grade greater than or equal to ≥2 bradycardia, or corrected qt (qtc by fridericia [qtcf]) greater than >480 msec (grade greater than >1). gastrointestinal disease (e.g. gastric or intestinal bypass surgery, pancreatic enzyme insufficiency, malabsorption syndrome, symptomatic inflammatory bowel disease, chronic diarrheal illness, bowel obstruction) that might interfere with drug absorption or with interpretation of gastrointestinal aes. pregnancy or breastfeeding. prior solid organ transplantation. use within 5 days prior to randomization of an approved or investigational therapy intended to treat covid-19 (e.g. remdesivir, , anti-interleukin [il]-6 antibodies, therapeutic anti-sars cov-2 antibodies or post-convalescent plasma, anti- sars cov-2 vaccine, bruton tyrosine kinase [btk] inhibitor), use within 3 months of chloroquine or hydroxychloroquine. note: participants are not precluded from undergoing evaluations involving observation, noninvasive diagnostic procedures or sampling, or questionnaires as follow-up to a prior study or as components of a concurrent noninterventional study. use within 5 days prior to randomization of a strong inhibitor or inducer of cytochrome p450 (cyp) 3a4 or expected requirement for chronic use of a strong inhibitor or inducer of cyp3a4 during study therapy. use within 5 days prior to randomization of drug that is a moderate-to-strong substrate of cyp2c9 (including warfarin, tolbutamide, phenytoin, glimepiride) or expected requirement for chronic use of such drugs during study therapy. use within 5 days prior to randomization of a drug known to prolong the qt interval ongoing immunosuppressive therapy including systemic or enteric corticosteroids. (note: at study entry, participants may be using intraarticular, inhaled, or topical corticosteroids. during study therapy, participants may use systemic, enteric, intraarticular, inhaled, or topical corticosteroids as required for intercurrent conditions.) any illness, medical condition, organ system dysfunction, or social situation, including mental illness or substance abuse, deemed by the investigator to be likely to interfere with a participant's ability to provide informed consent, adversely affect the participant's ability to cooperate and participate in the study, or compromise the interpretation of study results.

1. respiratory rate greater than or equal to ≥20 breaths per minute. 2. oxygen saturation by pulse oximetry less than or equal to ≤93 percent % on room air or requirement for supplemental oxygen to maintain oxygen saturation greater than >93 percent %. 3. total news score greater than or equal to ≥6 or presence of a score of 3 on any of the individual news parameters. 4. radiographic evidence of pulmonary infiltrates (clinical x-ray within 2 days of referral) 5. hepatic profile showing any of the following: - serum alanine aminotransferase (alt) greater than >5 × upper limit of normal (uln) (ctcae grade greater than or equal to ≥3). - serum aspartate aminotransferase (ast) greater than >5 × uln (ctcae grade greater than or equal to ≥3). - serum bilirubin greater than >1.5 × uln (ctcae grade greater than or equal to ≥2). 6. renal profile showing an estimated creatinine clearance (eclcr) less than <30 ml/minute (with eclcr to be calculated by the method at the laboratory performing the serum creatinine test). 7. presence of a cancer with disease manifestations or therapy that could adversely affect subject safety or longevity, create the potential for drug-drug interactions, or compromise the interpretation of study results. 8. significant cardiovascular disease (e.g. myocardial infarction, arterial thromboembolism, cerebrovascular thromboembolism) within 1 month prior to start of study therapy; unstable angina; symptomatic peripheral vascular disease; ctcae grade greater than or equal to ≥2 congestive heart failure; or uncontrolled ctcae grade greater than or equal to ≥3 hypertension (diastolic blood pressure greater than or equal to ≥100 mmhg or systolic blood pressure greater than or equal to ≥160 mmhg) despite antihypertensive therapy. 9. significant screening ecg abnormalities, including atrial fibrillation/flutter, 2nd degree atrioventricular (av) block type ii, 3rd-degree av block, grade greater than or equal to ≥2 bradycardia, or corrected qt (qtc by fridericia [qtcf]) greater than >480 msec (grade greater than >1). 10. gastrointestinal disease (e.g. gastric or intestinal bypass surgery, pancreatic enzyme insufficiency, malabsorption syndrome, symptomatic inflammatory bowel disease, chronic diarrheal illness, bowel obstruction) that might interfere with drug absorption or with interpretation of gastrointestinal aes. 11. pregnancy or breastfeeding. 12. prior solid organ transplantation. 13. use within 5 days prior to randomization of an approved or investigational therapy intended to treat covid-19 (e.g. remdesivir, , anti-interleukin [il]-6 antibodies, therapeutic anti-sars cov-2 antibodies or post-convalescent plasma, anti- sars cov-2 vaccine, bruton tyrosine kinase [btk] inhibitor), use within 3 months of chloroquine or hydroxychloroquine. note: participants are not precluded from undergoing evaluations involving observation, noninvasive diagnostic procedures or sampling, or questionnaires as follow-up to a prior study or as components of a concurrent noninterventional study. 14. use within 5 days prior to randomization of a strong inhibitor or inducer of cytochrome p450 (cyp) 3a4 or expected requirement for chronic use of a strong inhibitor or inducer of cyp3a4 during study therapy. 15. use within 5 days prior to randomization of drug that is a moderate-to-strong substrate of cyp2c9 (including warfarin, tolbutamide, phenytoin, glimepiride) or expected requirement for chronic use of such drugs during study therapy. 16. use within 5 days prior to randomization of a drug known to prolong the qt interval 17. ongoing immunosuppressive therapy including systemic or enteric corticosteroids. (note: at study entry, participants may be using intraarticular, inhaled, or topical corticosteroids. during study therapy, participants may use systemic, enteric, intraarticular, inhaled, or topical corticosteroids as required for intercurrent conditions.) 18. any illness, medical condition, organ system dysfunction, or social situation, including mental illness or substance abuse, deemed by the investigator to be likely to interfere with a participant's ability to provide informed consent, adversely affect the participant's ability to cooperate and participate in the study, or compromise the interpretation of study results.

1. respiratory rate greater than or equal to ≥20 breaths per minute. 2. oxygen saturation by pulse oximetry less than or equal to ≤93 percent % on room air or requirement for supplemental oxygen to maintain oxygen saturation greater than >93 percent %. 3. total news score greater than or equal to ≥6 or presence of a score of 3 on any of the individual news parameters. 4. radiographic evidence of pulmonary infiltrates (clinical x-ray within 2 days of referral) 5. hepatic profile showing any of the following: - serum alanine aminotransferase (alt) greater than >5 × upper limit of normal (uln) (ctcae grade greater than or equal to ≥3). - serum aspartate aminotransferase (ast) greater than >5 × uln (ctcae grade greater than or equal to ≥3). - serum bilirubin greater than >1.5 × uln (ctcae grade greater than or equal to ≥2). 6. renal profile showing an estimated creatinine clearance (eclcr) less than <30 ml/minute (with eclcr to be calculated by the method at the laboratory performing the serum creatinine test). 7. presence of a cancer with disease manifestations or therapy that could adversely affect subject safety or longevity, create the potential for drug-drug interactions, or compromise the interpretation of study results. 8. significant cardiovascular disease (e.g. myocardial infarction, arterial thromboembolism, cerebrovascular thromboembolism) within 1 month prior to start of study therapy; unstable angina; symptomatic peripheral vascular disease; ctcae grade greater than or equal to ≥2 congestive heart failure; or uncontrolled ctcae grade greater than or equal to ≥3 hypertension (diastolic blood pressure greater than or equal to ≥100 mmhg or systolic blood pressure greater than or equal to ≥160 mmhg) despite antihypertensive therapy. 9. significant screening ecg abnormalities, including atrial fibrillation/flutter, 2nd degree atrioventricular (av) block type ii, 3rd-degree av block, grade greater than or equal to ≥2 bradycardia, or corrected qt (qtc by fridericia [qtcf]) greater than >480 msec (grade greater than >1). 10. gastrointestinal disease (e.g. gastric or intestinal bypass surgery, pancreatic enzyme insufficiency, malabsorption syndrome, symptomatic inflammatory bowel disease, chronic diarrheal illness, bowel obstruction) that might interfere with drug absorption or with interpretation of gastrointestinal aes. 11. pregnancy or breastfeeding. 12. prior solid organ transplantation. 13. use within 5 days prior to randomization of an approved or investigational therapy intended to treat covid-19 (e.g. remdesivir, , anti-interleukin [il]-6 antibodies, therapeutic anti-sars cov-2 antibodies or post-convalescent plasma, anti- sars cov-2 vaccine, bruton tyrosine kinase [btk] inhibitor), use within 3 months of chloroquine or hydroxychloroquine. note: participants are not precluded from undergoing evaluations involving observation, noninvasive diagnostic procedures or sampling, or questionnaires as follow-up to a prior study or as components of a concurrent noninterventional study. 14. use within 5 days prior to randomization of a strong inhibitor or inducer of cytochrome p450 (cyp) 3a4 or expected requirement for chronic use of a strong inhibitor or inducer of cyp3a4 during study therapy. 15. use within 5 days prior to randomization of drug that is a moderate-to-strong substrate of cyp2c9 (including warfarin, tolbutamide, phenytoin, glimepiride) or expected requirement for chronic use of such drugs during study therapy. 16. use within 5 days prior to randomization of a drug known to prolong the qt interval 17. ongoing immunosuppressive therapy including systemic or enteric corticosteroids. (note: at study entry, participants may be using intraarticular, inhaled, or topical corticosteroids. during study therapy, participants may use systemic, enteric, intraarticular, inhaled, or topical corticosteroids as required for intercurrent conditions.) 18. any illness, medical condition, organ system dysfunction, or social situation, including mental illness or substance abuse, deemed by the investigator to be likely to interfere with a participant's ability to provide informed consent, adversely affect the participant's ability to cooperate and participate in the study, or compromise the interpretation of study results.