A Study to Evaluate Efficacy and Safety of PTC299 (Emvododstat) in Hospitalized Participants With Coronavirus (COVID-19)

Open to people ages 18 years and up

• Signed and dated informed consent document(s).
• Agrees to the collection of nasopharyngeal swabs and venous blood and all other protocol-specified procedures.
• Male or non-pregnant female adult ≥18 years of age at time of enrollment.
• Hospitalized and has laboratory-confirmed infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
• Symptom onset was ≤10 days prior to screening.
• Has oxygen saturation SpO2 <94% on room air.
• Has at least one of a respiratory rate >24 breaths/minute or cough.
• Lung involvement as confirmed by radiographic infiltrates observed on imaging (chest X-ray, computed tomography (CT) scan, or an equivalent test).
• Women of childbearing potential (as defined in [CTFG 2014]) must have a negative pregnancy test at screening and agree to abstinence or the use at least one of the following highly effective forms of contraception (with a failure rate of <1% per year when used consistently and correctly). Contraception or abstinence must be continued for the duration of the study following discharge from the hospital, and for up to 50 days after the last dose of study drug:

i) combined (estrogen and progestogen containing) hormonal contraception associated with inhibition of ovulation: oral, intravaginal, and transdermal ii) progestogen-only hormonal contraception associated with inhibition of ovulation: oral, injectable, and implantable iii) intrauterine device iv) intrauterine hormone-releasing system v) vasectomized partner with confirmed azoospermia All females will be considered of childbearing potential unless they are postmenopausal (at least 12 months consecutive amenorrhea in the appropriate age group without other known or suspected cause) or have been sterilized surgically (for example, bilateral tubal ligation, hysterectomy, bilateral oophorectomy).

• Men sexually active with women of childbearing potential who have not had a vasectomy must agree to use a barrier method of birth control during the study following discharge from the hospital and for up to 50 days after the last dose of study drug.

• Requires mechanical ventilation.
• Current participation in any other interventional study.
• Alanine transaminase/aspartate transaminase levels ≥3 times the upper limit of normal (×ULN) or total bilirubin (Tbili) ≥2×ULN.
• Lymphocyte count <500 lymphocytes/microliter (μL) or hemoglobin <11 grams/deciliter (g/dL).
• Stage 4 severe chronic kidney disease or requiring dialysis (that is, estimated glomerular filtration rate <30).
• Any other condition, that in the opinion of the Investigator, may be cause to exclude the participant from the study.
• Use of steroids (except dexamethasone), sensitive CYP2D6 substrates, CYP2C inducers, IL-6 neutralizing antibodies, IL-6 receptor inhibitors, or any investigational therapy.
• Pregnancy or breast feeding.
• Anticipated transfer to another hospital which is not a study site within 72 hours.
• Known allergy to PTC299 or excipients.