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

NCT07658534 | Recruiting Phase 2

• 1 other identifier: AK0529-2009
• Study Type: interventional
• Target: 290
• Locations: 1 country
• Sites: 9

Brief Summary

Respiratory syncytial virus (RSV) is recognized worldwide as a significant pathogen causing lower respiratory tract infection in infants, the elderly, and immunocompromised patients, which may cause bronchiolitis or pneumonia, and affect the cardiovascular system, central nervous system and the renal system, resulting in hospitalization and death risks in children and also high-risk adults, particularly the elderly. The purpose of this study is to evaluate the efficacy of Ziresovir (AK0529) compared to placebo with respect to the time to resolution of RSV lower respiratory tract disease (LRTD) symptoms.

Conditions

Respiratory Syncytial Virus Infections

Keywords

Ziresovir; RSV; Chronic Respiratory Disease; Heart Disease; The Elderly

Outcome Measures

Primary Outcomes (1)

• Time from first dose to resolution of LRTD symptoms

  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.

  Up to Day 27

Secondary Outcomes (7)

• Resolution rates of LRTD symptoms after treatment

  Day 3, Day 6, Day 13, Day 27

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

  Up to Day 27

• Resolution rate of upper respiratory, systemic, and total symptoms

  Day 3, Day 6, Day 13, Day 27

• Change from baseline in RSV viral load (VL)

  Day 2 to Day6, Day 13, Day 27

• Change from baseline in RiiQ total score and domain scores

  Day 3, Day 6, Day 13, Day 27

Other Outcomes (4)

• Proportion of participants hospitalized

  Up to Day 27

• Hospitalization duration

  Up to Day 27

• Supplemental oxygen use

  Up to Day 27

Study Arms (3)

Active drug(200mg)

EXPERIMENTAL

The participants will receive 200 mg AK0529 twice daily for 5 days from D1 to D5.

Drug: Ziresovir (AK0529)

Active drug(300mg)

EXPERIMENTAL

The participants will receive 300 mg AK0529 twice daily for 5 days from D1 to D5.

Drug: Ziresovir (AK0529)

Placebo

PLACEBO COMPARATOR

The participants will receive placebo of 200 mg, or 300 mg twice daily for 5 days from D1 to D5.

Drug: Placebo

Interventions

Ziresovir (AK0529) DRUG

Active Substance: AK0529 Pharmaceutical Form: Enteric Capsules Route of Administration: Oral

Active drug(200mg); Active drug(300mg)

Placebo DRUG

Active Substance: Placebo Pharmaceutical Form: Enteric Capsules Route of Administration: Oral

Placebo

Eligibility Criteria

• Age: 18 Years - 85 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Aged 18-85 years (inclusive), regardless of gender.
• Diagnosed with RSV infection by antigen or nucleic acid test within 36 hours before first dose.
• Have at least one of the following high-risk conditions for RSV infection: Chronic respiratory disease; heart disease; immunocompromised status; other chronic disease; age ≥65 years.
• Presence of at least one new LRTD symptom or worsening of a pre-existing LRTD symptom (specifically: cough, expectoration, wheezing, shortness of breath), with at least one individual symptom rated as moderate or severe (score 2 or 3 per RiiQ Symptom Scale).
• Time from symptom onset (or worsening of pre-existing symptoms) to first dose ≤5 days. (Onset defined as time of first RSV-related symptom/sign confirmed by investigator; pre-existing symptoms are those due to underlying conditions)

You may not qualify if:

• Diagnosed with influenza or COVID-19 infection within 7 days prior to providing informed consent.
• Suspected bacterial co-infection.
• Received any potentially anti-RSV agents (e.g., ribavirin, long-acting interferon) within 5 half-lives prior to the first study dose, or plans to use such agents during the study.
• Received prohibited medications, or plans to use prohibited medications during the study.
• Has a severe or unstable gastrointestinal, hepatic, renal, hematologic disorder, or malignancy.
• Has a known allergy, hypersensitivity, or intolerance to AK0529 or to any excipients in the AK0529 or placebo formulation.
• Female participants with a positive pregnancy test result, or who are breastfeeding.
• Refusal to use effective contraception during the trial period.

Sponsors & Collaborators

• Shanghai Ark Biopharmaceutical Co., Ltd.: lead

Study Sites (9)

China-Japan Friendship Hospital

Beijing, Beijing Municipality, China

RECRUITING

Guangzhou Medical University Panyu Central Hospital

Guangzhou, Guangdong, China

NOT YET RECRUITING

Cangzhou Hospital of Integrated TCM-WM

Cangzhou, Hebei, China

RECRUITING

The First Affiliated Hospital of Nanyang Medical College

Nanyang, Henan, China

RECRUITING

Henan Infectious Disease Hospital (The Sixth People's Hospital of Zhengzhou)

Zhengzhou, Henan, China

NOT YET RECRUITING

Wuhan Sixth Hospital

Wuhan, Hubei, China

RECRUITING

Zhejiang Hospital

Hangzhou, Zhejiang, China

NOT YET RECRUITING

People's Hospital of Rui'an City

Rui’an, Zhejiang, China

RECRUITING

Taizhou Hospital of Zhejiang Province

Taizhou, Zhejiang, China

RECRUITING

MeSH Terms

Conditions

Respiratory Syncytial Virus Infections; Heart Diseases

Interventions

ziresovir

Condition Hierarchy (Ancestors)

Pneumovirus Infections; Paramyxoviridae Infections; Mononegavirales Infections; RNA Virus Infections; Virus Diseases; Infections; Cardiovascular Diseases

Central Study Contacts

Chao Yu, Mater

CONTACT

+86 021-50681677; chao.yu@arkbiosciences.com

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Masking Details: Double-Blind
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: This clinical study is a randomized placebo-controlled parallel multi-center phase 2b/3 trial.

Study Record Dates

• First Submitted: March 30, 2026
• First Posted: June 22, 2026
• Study Start: March 3, 2026
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): January 1, 2029
• Last Updated: June 22, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

CN (9)