study to assess the efficacy and safety of sti-1558 in adult subjects with mild or moderate (covid-19)

Conditions: COVID-19

Summary: this is a multicenter, randomized, double-blind, placebo-controlled phase iii clinical study to evaluate the efficacy and safety of sti-1558 in adult subjects with mild/moderate covid-19. one thousand and two hundred adult subjects with mild/moderate covid-19 (including subjects with high risk factors for progression into severe cases) are planned to be enrolled and randomized in a ratio of 1:1 into the test group or the placebo group (600 in the test group and 600 in the placebo group).

one thousand and two hundred adult subjects with mild/moderate covid-19 (including subjects with high risk factors for progression into severe cases) are planned to be enrolled and randomized in a ratio of 1:1 into the test group or the placebo group. randomization and stratification factors include clinical type (mild vs. moderate) of covid-19, high risk factors for severe disease (with vs. without), history of sars-cov-2 vaccination or infection (yes vs. no). subjects in the test group will receive sti-1558, and subjects in the placebo group will receive sti-1558 placebo. sti-1558 and sti-1558 placebo will be orally administered under fasting condition twice daily (bid) for 5 days (10 doses in total) at a dose of 600 mg and 0 mg, respectively; the two doses administered will be at a minimum interval of 8 hours (≥8 h). efficacy and safety will be assessed until d29 after the first dose.

Eligibility criteria:
inclusion criteria: 1. males or females aged ≥18 years; 2. subjects comply with the diagnostic criteria for mild or moderate covid-19 specified in the protocol for the diagnosis and treatment of novel coronavirus pneumonia (trial version 9) released by china's national health commission; 3. first presence of positive rt-pcr or rapid antigen assay for sars-cov-2 with nasopharyngeal or oropharyngeal swabs within 4 days prior to the first dose (≤4 days from the first dose); 4. first presence of at least 1 of 14 symptoms of covid-19 within 3 days prior to the first dose (≤3 days/72 hours from the first dose) ; 5. subjects with at least 2 of 11 target symptoms of covid-19 within 24 hours prior to the first dose (≤24 hours from the first dose), including at least 1 designated symptom (stuffy or runny nose, sore throat or dry throat, cough, feeling hot or feverish, shortness of breath or difficulty breathing), and score of at least 1 designated symptom ≥2 ; 6. women of childbearing potential (wocbp) (women of non-childbearing potential defined as women who have undergone hysterectomy or bilateral oophorectomy or bilateral salpingectomy or bilateral tubal ligation/closure, or who are infertile due to a congenital or acquired condition, or sexually mature women spontaneously menopausal for ≥ 12 months) must have a negative pregnancy test during the screening period; 7. female subjects of childbearing potential or male subjects whose partners are of childbearing potential must agree to use a highly effective contraceptive method from screening to 30 days after the last dose; 8. can understand and abide by the procedures and methods of this clinical trial. exclusion criteria: 1. known allergy to any ingredient of the study drug; 2. subjects comply with the diagnostic criteria for severe or critical covid-19 specified in the protocol for the diagnosis and treatment of novel coronavirus pneumonia (trial version 9) released by china's national health commission prior to the first dose; 3. subjects urgently require or is expected to require nasal high-flow oxygen therapy or non-invasive positive pressure ventilation, invasive mechanical ventilation or ecmo prior to the first dose; 4. subjects with abnormal liver function at screening: total bilirubin ≥ 1.5 × upper limit of normal (uln), alanine aminotransferase (alt) or aspartate aminotransferase (ast) ≥ 3 × uln; 5. subjects with active or uncontrolled hepatopathy: including cirrhosis, child-pugh grade b or c, acute liver failure, etc.; 6. subjects with concomitant severe renal insufficiency (estimated glomerular filtration rate \[egfr\]\<45 ml/min, calculated using the serum creatinine based chronic kidney disease epidemiology collaboration \[ckd-epi\] equation, refer to appendix 6 for the calculation formula) or on continuous renal replacement therapy, hemodialysis or peritoneal dialysis; 7. subjects with impaired immune system (including subjects who are on systemic or inhaled corticosteroids or other immunosuppressants, or subjects with cancer progression or recurrence, or with human immunodeficiency virus \[hiv\] infection); 8. subjects with acute episodes of chronic respiratory diseases (including bronchial asthma, chronic obstructive pulmonary disease, etc.); 9. subjects with a history of dysphagia or any gastrointestinal disorder that affects drug adsorption; 10. subjects with suspected or confirmed acute systemic infections other than covid-19 (e.g., concomitant influenza), which may interfere with the evaluation of responses to the study intervention; 11. subjects who have underwent major surgery within 14 days prior to the first dose, or have not completely recovered from surgery or plan to undergo surgery during the study period; 12. subjects with complications that are, in the opinion of the investigator, life-threatening within 30 days prior to the first dose; 13. subjects have received anti-sars-cov-2 chemical drugs such as 3cl protease inhibitors or rna dependent rna polymerase (rdrp) inhibitors or angiotensin converting enzyme 2 (ace-2) and transmembrane protease serine 2 (tmprss2) degrading agents within 14 days prior to the first dose; 14. subjects have received covid-19 patients' convalescent plasma or covid-19 human immunoglobulin or interleukin-6 (il-6) inhibitors or anti-sars cov-2 neutralizing antibodies within 30 days or 5 half-lives (whichever is longer) prior to the first dose; 15. subjects have had any sars-cov-2 vaccination within 3 months prior to the first dose; 16. subjects have received any potent inhibitor or inducer of cytochrome p450 (cyp) 3a4 within 28 days or 5 half-lives (whichever is shorter) prior to the first dose; 17. subjects who are currently participating in an interventional clinical study of other investigational drugs or devices, including other studies on covid-19; 18. subjects have received any investigational drug within 30 days or 5 half-lives (whichever is longer) prior to the first dose; 19. subjects have previously participated in this study or other studies of sti-1558; 20. pregnant or lactating women; 21. subjects with active serious mental illness, medical disorder or other symptoms/conditions that, in the opinion of the investigator, may affect treatment, compliance or the ability to provide informed consent.