Clinical Trial Evaluating the Efficacy and Safety of Favipiravir in Moderate to Severe COVID-19 Patients

Inclusion Criteria: 1. Male and female patients aged 21 to 80 years (both inclusive) 2. Patients who have tested positive for SARS-CoV-2 by Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR) assay using a respiratory tract sample (either nasopharyngeal swab OR oropharyngeal swab OR nasal aspirate OR tracheobronchial aspirate) collected within 72 hours of randomization 3. Patients should be hospitalized 4. Patients having moderate or severe COVID-19\* with a score of \> 4 on the 10-point ordinal scale of clinical status used by WHO in the SOLIDARITY trial at baseline assessment \[i.e., patients with blood oxygen saturation (SpO2) \<95% at rest on room air at sea level and requiring supplemental oxygen\]. \*Note: This includes patients clinically assigned as: I. 'moderate' COVID-19 1. symptoms which could include fever, cough, sore throat, malaise, headache, muscle pain, gastrointestinal symptoms or shortness of breath with exertion and/or clinical signs, such as respiratory rate ≥20 breaths per minute or heart rate ≥90 beats per minute AND 2. blood oxygen saturation (SpO2) of 94% at rest on room air at sea level II. 'severe' COVID-19 1. symptoms which could include any symptom of moderate illness or shortness of breath at rest, or respiratory distress and/or clinical signs, such as respiratory rate ≥30 per minute or heart rate ≥125 per minute AND 2. blood oxygen saturation (SpO2) ≤93% on room air at sea level or PaO2/FiO2 \<300\* The above-mentioned definitions of COVID-19 severity are adapted from the FDA Guidance document "COVID-19: Developing Drugs and Biological Products for Treatment or Prevention - Guidance for Industry Final Document" dated May 2020. 5. Female patients of childbearing potential\* 1. must have a negative serum pregnancy test at screening 2. should not be lactating; and not planning to become pregnant/breast feed during the treatment period and for 7 days after the last dose of study medication. 3. should commit to the use of TWO forms of study-acceptable contraception methods, including a barrier method (eg. diaphragm) along with one or more of the following methods of contraception for the duration of the treatment period and for 7 days after the last dose of study medication: i) hormonal methods \[insertable, injectable, transdermal, or combination oral (estrogen+ progestin)\], or ii) intrauterine contraceptive device Note: Female patients who are sexually abstinent or whose male sexual partner has undergone vasectomy at least three months prior to the start of study treatment in the trial may be enrolled at the Investigator's discretion, provided that they are counseled to remain sexually inactive for the duration of the study and understand the possible risks involved in getting pregnant during the study. Patients must also agree to use TWO forms of study-acceptable contraception methods should they become sexually active during the treatment period and for 7 days after the last dose of study medication. \*Note: A female patient is considered of childbearing potential unless she is: 1. postmenopausal for at least 12 months prior to study product administration, or 2. without a uterus and/or both ovaries or has been surgically sterilized (i.e, tubal ligation or has a fallopian tube blocking coil) for at least 6 months prior to study product administration. 6. Male patients should agree to abstain from sexual intercourse or to use double-barrier contraception (e.g. condom with spermicide) for the duration of the treatment period in the study and for at least 7 days after receiving the last dose of study medication. Male patients should also avoid semen donation or providing semen for in-vitro fertilization during the above-mentioned duration. 7. Able and willing to provide informed consent 8. Able to understand the trial requirements and comply with trial medications and assessments in the opinion of the Investigator 9. Should not have received investigational treatment from participation in another clinical trial within 30 days prior to randomization in the current trial and agrees not to participate in other clinical studies during the entire study period Exclusion Criteria: 1. Critically ill patients, defined as those who are candidates for endotracheal intubation and mechanical ventilation, oxygen delivered by high- flow nasal cannula, (heated, humidified, oxygen delivered via reinforced nasal cannula at flow rates \>20 L/min with fraction of delivered oxygen ≥0.5), non-invasive positive pressure ventilation, Extracorporeal Membrane Oxygenation (ECMO) , or clinical diagnosis of respiratory failure (i.e., clinical need for one of the preceding therapies, but preceding therapies not able to be administered in setting of resource limitation) and those with shock (defined by systolic blood pressure (BP) \<90 mm Hg, or diastolic BP \<60 mm Hg or requiring vasopressors) or multi-organ dysfunction/failure, at baseline Note: The above-mentioned definition of 'critically ill' COVID-19 patients is as defined in the FDA Guidance document "COVID-19: Developing Drugs and Biological Products for Treatment or Prevention - Guidance for Industry Final Document" dated May 2020 2. Patients in whom the first onset of symptoms/signs suggestive of COVID-19 illness was observed \>10 days earlier to the baseline assessment and randomization 3. Patients who have used interferon beta 1-a (IFN-β-1a) preparations or drugs with reported anti-viral action against SARS-CoV-2 (hydroxychloroquine sulfate, chloroquine phosphate, lopinavir-ritonavir combination drugs, ciclesonide, nafamostat mesylate, camostat mesylate) within 8 days after development of fever (≥37.5°C) Note: The above-mentioned exclusion criterion is not applicable in case of patients with history of human immunodeficiency virus infection or infective hepatitis in whom use of anti-viral drugs or interferons are prescribed for treatment of the underlying condition and who are currently receiving one or more of these medications (as maintenance treatment) at the time of randomization. The infection episode in question is a relapse of, or reinfection with SARS-CoV-2 4. Patients suspected to have a complication of congestive cardiac failure based on Investigator's clinical judgement 5. Patients with moderate and severe hepatic dysfunction equivalent to Grade B and Grade C in the Child-Pugh classification respectively 6. Patients with alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels \> 5 times upper limit of normal (ULN) at screening evaluation 7. Patients with renal impairment requiring dialysis 8. Patients with serum uric acid higher than the ULN at screening evaluation 9. Patients with history of hereditary xanthinuria 10. Patients who have been diagnosed with xanthine urinary calculus 11. Patients with a history of gout or patients who are currently being treated for gout 12. Patients who are taking immunosuppressants 13. Patients who were administered Favipiravir in the past 30 days 14. Patients with known hypersensitivity reaction to Favipiravir