Study to Assess the Efficacy and Safety of GP681 Versus Placebo for Postexposure Prophylaxis Against Influenza

Q: Who can participate in NCT06574503?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

Q: How do I contact the trial site for NCT06574503?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Q: Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Q: Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

A Phase III, Multicenter, Randomized, Double-blind, Placebo-controlled, Clinical Efficacy and Safety Study of GP681 Tablets for Post-exposure Prophylaxis Against Influenza in Adults and Adolescents

Study to Assess the Efficacy and Safety of GP681 Versus Placebo for Postexposure Prophylaxis Against Influenza (NCT06574503) is a Phase 3 interventional studying Influenza, sponsored by Jiangxi Qingfeng Pharmaceutical Co. Ltd.. RECRUITING as of the most recent ClinicalTrials.gov update. Talk to your doctor before contacting the trial site.

About This Trial

Index patients who are infected with influenza virus (Q-PCR positive) can be treated with anti-influenza drugs if their influenza symptoms onset was within 48 hours of screening. Their eligible households will be randomized to either GP681 tablets or placebo if at least 1 household contacts have not received influenza vaccine with 6 months of screening and if all household contacts screen negative for influenza infection. The main endpoints are assessed based on multiple respiratory swabs, obtained from household contacts up to Day 10, and through the assessment of symptoms.

What Stage of Research Is This?

Phase 3 trials confirm efficacy and safety in large patient groups (often 300–3,000+) and form the evidence base for an FDA approval submission. For Influenza, Phase 3 studies typically randomize participants between the investigational treatment and either a placebo or current standard of care. A successful Phase 3 result is the threshold most treatments need to clear before regulatory approval.

This trial is currently recruiting participants. The sponsor has registered the study with ClinicalTrials.gov as actively enrolling, which means new applicants who meet the eligibility criteria can be considered for screening. Trial status can change between updates — confirm current recruiting status with the study contact before traveling for a screening visit.

A target enrollment of 748 participants makes this a sizable late-stage trial. Studies in this range typically have enough power to detect clinically meaningful differences from a comparator and to characterize less-common side effects.

Who May Be Eligible (Plain English)

Who May Qualify: Index patients(IPs) 1. Male or female patients aged≥2 years at the time of signing the willing to sign a consent form form. 2. The first patient in a household with a diagnosis of influenza virus infection confirmed by all of the following in the influenza season: 3. Positive Influenza rapid antigen test or Polymerase chain reaction (PCR), and; 4. Fever (axillary temperature ≥37.3℃) in the predose examinations or \> 4 hours after dosing of antipyretics if they were taken. 5. Patients with onset of fever within 48 hours or less at willing to sign a consent form. 6. Patients live in a household where all household contacts are expected to meet the key household contacts inclusion criteria (criteria 2, 3, \& 4). 7. Patients and/or their guardian who are willing to provide written willing to sign a consent form and consent to participate in the study, able to understand the study and comply with all study procedures. Household contacts of index patients: 1. Male or female patients aged≥12 years at the time of signing the willing to sign a consent form form. 2. Household contacts who are able to provide willing to sign a consent form within 24 hours or less from willing to sign a consent form in index patients. 3. Subjects who had lived with the index patient for 3 months or more prior to willing to sign a consent form. 4. Subjects who meet all of the following criteria and are judged not to have influenza virus infection by the investigator. 5. Negative Influenza rapid antigen test or Polymerase chain reaction (PCR), and; 6. Subjects who have a body temperature (axillary) \< 37.3°C at Screening, and; 7. Subjects who have no influenza like symptoms (cough, sore throat, headache, nasal discharge/nasal congestion, feverishness or chills, muscle or joint pain, and fatigue) at Screening. 8. Household contacts intended for full study have not received influenza vaccine within 6 months prior to screening; ...See full criteria on ClinicalTrials.gov Always talk to your doctor about whether this trial is right for you.

These are translations of the protocol\'s inclusion and exclusion criteria, simplified for patients and caregivers. The original clinical text appears below. Eligibility is ultimately confirmed by the trial site\'s screening process — this summary is a starting point for a conversation with your doctor, not a final determination.

Original Eligibility Criteria

View original clinical language

Inclusion Criteria: Index patients(IPs) 1. Male or female patients aged≥2 years at the time of signing the informed consent form. 2. The first patient in a household with a diagnosis of influenza virus infection confirmed by all of the following in the influenza season: 3. Positive Influenza rapid antigen test or Polymerase chain reaction (PCR), and; 4. Fever (axillary temperature ≥37.3℃) in the predose examinations or \> 4 hours after dosing of antipyretics if they were taken. 5. Patients with onset of fever within 48 hours or less at informed consent. 6. Patients live in a household where all household contacts are expected to meet the key household contacts inclusion criteria (criteria 2, 3, \& 4). 7. Patients and/or their guardian who are willing to provide written informed consent and consent to participate in the study, able to understand the study and comply with all study procedures. Household contacts of index patients: 1. Male or female patients aged≥12 years at the time of signing the informed consent form. 2. Household contacts who are able to provide informed consent within 24 hours or less from informed consent in index patients. 3. Subjects who had lived with the index patient for 3 months or more prior to informed consent. 4. Subjects who meet all of the following criteria and are judged not to have influenza virus infection by the investigator. 5. Negative Influenza rapid antigen test or Polymerase chain reaction (PCR), and; 6. Subjects who have a body temperature (axillary) \< 37.3°C at Screening, and; 7. Subjects who have no influenza like symptoms (cough, sore throat, headache, nasal discharge/nasal congestion, feverishness or chills, muscle or joint pain, and fatigue) at Screening. 8. Household contacts intended for full study have not received influenza vaccine within 6 months prior to screening; 9. Subjects and/or their guardian who are willing to provide written informed consent and consent to participate in the study, able to understand the study and comply with all study procedures, including patient health diary records. Exclusion Criteria: Household contacts of index patients: 1. History of allergic reactions attributed to GP681 or any of the ingredients of its formulation. 2. Subjects with household members other than the index patient that was diagnosed with or strongly suspected to have influenza in the past 12 weeks. 3. subjects with concurrent bacterial or other virus infections requiring systemic antimicrobial and/or antiviral therapy at the pre-dose examinations. 4. Subjects who are unable to live with the index patient from Screening until Day 10. 5. Known history of dysphagia or any gastrointestinal disease that affects drug absorption (including but not limited to reflux esophagitis, chronic diarrhea, inflammatory bowel disease, intestinal tuberculosis, gastrinoma, short bowel syndrome, stomach after subtotal resection, etc.). 6. Subjects who have any underlying diseases requiring systemic , treatment of antipyretics/analgesics, corticosteroids, or immunosuppressive agents. 7. Subjects with human immunodeficiency virus \[HIV\] infection. 8. Subjects with severe (Grade 3 or higher of Common Terminology Criteria for Adverse Events \[CTCAE\] ver. 5) underlying diseases. 9. Treatment with anti-influenza virus drugs (oseltamivir, zanamivir, peramivir, favipiravir, abidol, baloxavir marboxil, amantadine, or rimantadine) within 2 weeks before screening. 10. Known history of alcohol abuse (Average weekly intake of alcohol is more than 14 units alcohol (1 units ≈ 360 mL beer, or 45 mL spirits with 40% content, or 150 mL wine) or drug abuse at screening; 11. Women who are pregnant, breastfeeding, or have a positive pregnancy test at the predose examinations. The following female patients who have documentation of either a or below do not need to undergo a pregnancy test at the predose examinations: 1. Postmenopausal women (defined as cessation of regular menstrual periods for 2 years or more and aged more than 50 years old) 2. Women who are surgically sterile by hysterectomy, bilateral oophorectomy, or tubal ligation 12. Has received any investigational agents or devices for any indication within 30 days prior to Screening. 13. Subjects who, in the opinion of the Investigator, may not be qualified or suitable for the study.

Treatments Being Tested

DRUG

GP681 40mg

2X20mg tablets taken orally

DRUG

GP681 Simulant

Placebo tablets matching GP681 40mg

Locations (1)

Trial sites listed on ClinicalTrials.gov for this study. Site activation status can vary — confirm with the specific site before traveling for a screening visit.

Shulan (Hang Zhou) Hospital

Hanzhou, China

How to Talk to Your Doctor About This Trial

Bring the printable summary of this trial — including the NCT ID (NCT06574503), the sponsor (Jiangxi Qingfeng Pharmaceutical Co. Ltd.), and the key eligibility criteria — to your next appointment. Your doctor can review the inclusion and exclusion criteria against your medical history, lab values, and current treatments to assess whether you are likely to qualify. They can also help you weigh whether trial participation makes sense alongside your existing care plan.

Useful questions to walk through together: What does the trial protocol require beyond standard care? How long is the active treatment phase, and how long is follow-up? Are there study visits at sites I can reach? Who pays for the trial-specific procedures, and who pays for standard-of-care portions? See our 25 questions to ask about clinical trials guide for a more complete checklist.

Authoritative Sources

The official record for this trial lives on ClinicalTrials.gov — the federal registry maintained by the National Library of Medicine at NIH. For background on how this trial fits into the FDA approval pathway, see the FDA drug approval process. For oncology-specific guidance for patients considering trials, the National Cancer Institute publishes patient-oriented overviews. International trial registries are aggregated by the WHO ICTRP.

Frequently Asked Questions

What is the NCT06574503 clinical trial studying?

Who can participate in NCT06574503?

Eligibility for this trial depends on the specific inclusion and exclusion criteria set by the sponsor. The plain-English summary above translates the most important criteria into accessible language; the official clinical text is preserved in the collapsible section underneath. Whether you fit any specific trial is a medical decision your doctor needs to confirm — bring the trial information to your treating physician for a full review against your medical history.

How do I contact the trial site for NCT06574503?

Contact information registered with ClinicalTrials.gov is shown in the sidebar of this page. Before reaching out, confirm with your treating physician that this trial is appropriate for your situation. The trial site will then walk you through the screening process to determine final eligibility.

Is participating in a clinical trial safe?

Clinical trials in the United States are regulated by the FDA and overseen by Institutional Review Boards (IRBs) that review the protocol for safety. Risk varies by trial — Phase 1 studies test new treatments in humans for the first time, while Phase 3 trials use treatments that have already passed earlier safety screening. The informed consent document for any specific trial details the known risks and what to expect. Discuss those risks with your physician before deciding whether to participate.

Where can I verify the data on this page?

Every detail on this page comes directly from the ClinicalTrials.gov API. Click "View on ClinicalTrials.gov" in the sidebar to see the official, unmodified record. The federal record is always authoritative; this page is a structured presentation with a plain-English eligibility translation. For background on how clinical trials are regulated, see the FDA drug approval process documentation.

How This Page Is Built

Every field on this page is pulled directly from the ClinicalTrials.gov API v2 — no estimates, no proxies. The plain-English eligibility translation is generated from the original protocol text and reviewed for fidelity to the underlying clinical criteria. The original clinical text remains visible in the collapsible section above so users and clinicians can verify the translation. Read the full methodology for the data pipeline and known limitations.

Source: ClinicalTrials.gov API v2 record for NCT06574503. Maintained by the National Library of Medicine at NIH. Public domain. Cite as: "TrialFinderData. NCT06574503. Data: ClinicalTrials.gov."

Medical disclaimer: This page is informational, not medical advice. Talk to your doctor about whether a clinical trial is right for you.

Last updated 2026-05-08 · Data from ClinicalTrials.gov.