A Study of CP-COV03 Compared With Placebo in Participants With Dengue (Part 1) and Dengue-like Illness (Part 2)

In Phase 2, approximately 210 patients with NS1-positive dengue within 72 hours of fever onset will be randomized to receive placebo or CP-COV03 at doses of 450, 900, or 1,350 mg/day for 7 days. An interim analysis by an independent Data and Safety Monitoring Board (DSMB) will support dose selection for Phase 3.

• CP-COV03 (Drug): Oral administration
• Placebo (Drug): Oral administration

Primary outcomes

• [Part 1] Incidence and severity of Adverse Events (AEs) and Serious Adverse Events (SAEs) [From start of study intervention (Day 1) up to end of safety follow-up (Day 29)]: The incidence and severity of AEs / SAEs will be summarized by treatment group. Clinical laboratory abnormalities, vital sign changes, and electrocardiogram (ECG) findings will be reported as AEs if they are considered clinically significant.
• [Part 1] Average of dengue viral load on Day 3 [Baseline, Day 1, 2, 3]: The area under the log-transformed DENV RNA viral load (log10 VL) curve from baseline until Day 3 will be determined. The viral load is measured in plasma samples using reverse transcription polymerase chain reaction (RT-PCR).
• [Part 2] Time to sustained symptom improvement up to Day 15 [From baseline up to Day 15]: Sustained improvement of each targeted symptom is defined as the event occurring on the first 2 consecutive days when each symptom scored as moderate or severe at the time of enrollment is scored as mild or absent, and those scored mild or absent at the time of enrollment are scored as absent.

Secondary outcomes

• [Part 1, 2] Dengue viral load up to Day 6, 8, 15 [Baseline, Day 1, 2, 3, 6, 8, 15]: The viral load is measured in plasma samples using reverse transcription polymerase chain reaction (RT-PCR).
• [Part 1] Time to sustained symptom improvement up to Day 15 [From baseline up to Day 15]: Sustained improvement of each targeted symptom is defined as the event occurring on the first 2 consecutive days when each symptom scored as moderate or severe at the time of enrollment is scored as mild or absent, and those scored mild or absent at the time of enrollment are scored as absent.
• [Part 1, 2] Diagnosis of severe dengue fever or dengue hemorrhagic fever (DHF) [From baseline up to Day 15]: Assessment of the clinical course of dengue fever
• [Part 1] PK parameter - Area under the plasma concentration-time curve (AUC) [Day 1, Day 7]: Pharmacokinetic assessment of CP-COV03 in dengue fever patients
• [Part 1] PK parameter - Maximum observed plasma concentration (Cmax) [Day 1, Day 7]: Pharmacokinetic assessment of CP-COV03 in dengue fever patients
• [Part 1] PK parameter - Time to reach maximum plasma concentration (Tmax) [Day 1, Day 7]: Pharmacokinetic assessment of CP-COV03 in dengue fever patients
• [Part 1] PK parameter - Terminal elimination half-life (t½) [Day 1, Day 7]: Pharmacokinetic assessment of CP-COV03 in dengue fever patients

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Patients who are 18 years or over of age at time of screening.
* Patients who have at least two symptoms with a score of 2 or higher within 72 h from fever onset.
* Patients who are diagnosed with dengue by NS1 positive (Phase 2- Part 1 only). And patients who are classified as dengue, zika, influenza, COVID-19 and others (Phase 3- Part 2 only)

Exclusion Criteria:

* Patients who show severe dengue (WHO dengue guideline C, any severe symptoms or clinical laboratory results)
* Patients who have previously received dengue vaccine
* Patients who have chronic medical conditions such as uncontrolled diabetes mellitus, severe asthma requiring oral steroids or admission to the hospital in the previous 6 months for cardiac disease