A Study of Ziresovir (AK0529) in High-risk Adult With Respiratory Syncytial Virus (RSV) Infection.

Resolution rates of LRTD symptoms after treatment

LRTD symptoms (cough, shortness of breath, wheezing, expectoration) are assessed by the RiiQ symptom scale, which includes 13 symptoms: 2 upper respiratory (stuffy nose, sore throat), 4 lower respiratory (cough, expectoration, wheezing, shortness of breath), and 7 systemic (feeling feverish, headache, body aches/pains, neck pain, trouble sleeping, tiredness, poor appetite). Each symptom is scored as None (0), Mild (1), Moderate (2), or Severe (3), with a total score range of 0-39.

Time frame: Day 3, Day 6, Day 13, Day 27

Time from first dose to resolution of upper respiratory, systemic, and total symptoms

Upper respiratory, systemic, and total symptoms are assessed by the RiiQ symptom scale, which includes 13 symptoms: 2 upper respiratory (stuffy nose, sore throat), 4 lower respiratory (cough, expectoration, wheezing, shortness of breath), and 7 systemic (feeling feverish, headache, body aches/pains, neck pain, trouble sleeping, tiredness, poor appetite). Each symptom is scored as None (0), Mild (1), Moderate (2), or Severe (3), with a total score range of 0-39.

Time frame: Up to Day 27

Resolution rate of upper respiratory, systemic, and total symptoms

Upper respiratory, systemic, and total symptoms are assessed by the RiiQ symptom scale, which includes 13 symptoms: 2 upper respiratory (stuffy nose, sore throat), 4 lower respiratory (cough, expectoration, wheezing, shortness of breath), and 7 systemic (feeling feverish, headache, body aches/pains, neck pain, trouble sleeping, tiredness, poor appetite). Each symptom is scored as None (0), Mild (1), Moderate (2), or Severe (3), with a total score range of 0-39.

Time frame: Day 3, Day 6, Day 13, Day 27

Change from baseline in RSV viral load (VL)

RSV VL in nasopharyngeal samples from participants will be measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR)

Time frame: Day 2 to Day6, Day 13, Day 27

Change from baseline in RiiQ total score and domain scores

RSV symptoms are assessed by the RiiQ symptom scale, which includes 13 symptoms: 2 upper respiratory (stuffy nose, sore throat), 4 lower respiratory (cough, expectoration, wheezing, shortness of breath), and 7 systemic (feeling feverish, headache, body aches/pains, neck pain, trouble sleeping, tiredness, poor appetite). Each symptom is scored as None (0), Mild (1), Moderate (2), or Severe (3), with a total score range of 0-39.

Time frame: Day 3, Day 6, Day 13, Day 27

Trough plasma concentration of AK0529

Plasma concentration of AK0529 is reported. This outcome measure is planned to be analyzed for specified arm only. In this outcome measure, only those time points for which individual participants had data are reported.

Time frame: Day 5

Incidence and severity of treatment-emergent AEs (TEAEs), SAEs, and other AEs

An adverse events (AEs) is any untoward medical occurrence in a clinical study participant administered a pharmaceutical (investigational or non-investigational) product. An AE does not necessarily have a causal relationship with the intervention. Any clinically significant physical examinations, vital signs, clinical laboratory tests (including biochemistry, hematology, cardiac enzymes and urine analysis), 12-lead electrocardiograms (ECGs) and spirometry results were recorded as adverse events. Any AE which occurred at or after the initial administration of study intervention through the end of the study (that is, Day 27) was considered treatment-emergent. A Serious Adverse Events (SAEs) is any adverse event that results in death, is life-threatening, requires hospitalization, causes persistent disability, or results in a congenital anomaly. The severity of AEs/ SAEs is categorized by CTCAE6.0.

Time frame: Up to Day 27