The investigational long-acting antiviral drug-Fc conjugate will be evaluated in a U.S. Phase II trial to assess its potential to prevent seasonal influenza.
Shanghai Ark Biopharmaceutical Co., Ltd. (ArkBio) announced that the U.S. Food and Drug Administration (FDA) has cleared the Investigational New Drug (IND) application for AK0406, enabling the company to initiate a Phase II clinical trial evaluating the candidate for influenza prevention in the general adult population in the United States.
The milestone expands AK0406’s global clinical development program, following regulatory clearance in Australia and China.
Key Highlights
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U.S. FDA clearance: IND application for AK0406 cleared, enabling planned Phase II development.
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Novel drug approach: AK0406 is a long-acting antiviral drug-Fc conjugate (AFC) designed to combine direct antiviral activity with Fc-mediated immune clearance.
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Preclinical findings: Demonstrated broad-spectrum antiviral activity against influenza A and B strains in preclinical studies.
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Global development: The candidate has also received regulatory clearance to advance clinical development in Australia and China.
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Planned Phase II trial: A multicenter, randomized, double-blind, placebo-controlled study will evaluate influenza prevention, safety, tolerability, pharmacokinetics and immunogenicity.
Addressing Unmet Needs in Influenza Prevention
Seasonal vaccination remains a cornerstone of influenza prevention. However, changes in circulating influenza viruses and differences in individual immune responses can affect vaccine protection, particularly among older adults and people who are immunocompromised.
According to the U.S. Centers for Disease Control and Prevention (CDC), the 2025–2026 influenza season resulted in at least 32 million illnesses, 380,000 hospitalizations and 24,000 deaths in the United States.
These challenges highlight the need to explore additional preventive approaches that could complement existing influenza prevention strategies.
About AK0406: A Novel Antiviral Drug-Fc Conjugate
AK0406 is an investigational antiviral candidate discovered and developed by ArkBio. The molecule is designed by conjugating multiple potent small-molecule antivirals to an antibody Fc domain.
This approach aims to combine two mechanisms:
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Direct antiviral activity to act against influenza viruses.
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Fc-mediated immune clearance to support the removal of virus-associated targets through immune mechanisms.
In preclinical studies, AK0406 demonstrated broad-spectrum and potent antiviral activity against both influenza A and B strains. ArkBio has also optimized the candidate’s pharmacokinetic (PK) properties and good manufacturing practice (GMP) manufacturing process.
These findings support further clinical investigation. However, the candidate’s safety and efficacy in preventing influenza in humans remain to be established.
Global Clinical Development Progress
ArkBio has advanced AK0406 through several regulatory and clinical milestones:
| Timeline | Development milestone |
|---|---|
| February 2026 | Received Human Research Ethics Committee (HREC) approval in Australia to initiate a Phase I clinical trial. |
| July 2026 | Completed enrollment and dosing of healthy adult participants across all Phase I cohorts; the study entered follow-up. |
| August 2026 | Received IND clearance from China's National Medical Products Administration (NMPA) for influenza prevention. |
| October 2026 | Received U.S. FDA IND clearance, enabling planned Phase II clinical development in the United States. |
The latest clearance represents another step toward evaluating AK0406 across multiple regions.
Planned U.S. Phase II Clinical Trial
The planned U.S. Phase II study will be conducted during an influenza season and will use a multicenter, randomized, double-blind and placebo-controlled design.
The trial aims to evaluate AK0406 for influenza prevention in adults. Additional assessments will include:
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Safety and tolerability: To evaluate how participants respond to the investigational candidate.
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Pharmacokinetics: To characterize how the drug behaves in the body.
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Immunogenicity: To assess immune responses associated with the candidate.
The resulting data are expected to inform the next stages of AK0406’s global development strategy.
ArkBio plans to continue discussions with the FDA and China’s NMPA Center for Drug Evaluation (CDE) to advance Phase II development in the United States and China. The company intends to pursue parallel development pathways as it evaluates AK0406’s potential as an additional influenza prevention option.
About ArkBio
Founded in 2014, Shanghai Ark Biopharmaceutical Co., Ltd. is a commercial-stage biopharmaceutical company focused on discovering and developing innovative treatments for respiratory and lung diseases, as well as pediatric diseases.
The company has established proprietary technology platforms and a research and development pipeline through internal innovation and strategic collaborations.
Key pipeline assets include:
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Ziresovir (AK0529): A direct-acting antiviral candidate for respiratory syncytial virus (RSV) that has reported positive Phase III results.
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AK3280: An anti-fibrotic candidate for idiopathic pulmonary fibrosis (IPF) that has reported positive Phase II results and is being evaluated in a Phase III trial.
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AK0901: A treatment for attention-deficit/hyperactivity disorder (ADHD) approved and commercialized in China.
ArkBio has also established strategic partnerships with pharmaceutical companies, including Roche, Genentech and Qilu Pharmaceutical, as well as academic institutions and biotechnology companies.
What This Means for Influenza Prevention
The FDA clearance allows ArkBio to move AK0406 into planned Phase II development in the United States. If subsequent clinical trials demonstrate an acceptable safety profile and meaningful preventive benefit, the candidate could potentially offer an additional approach to influenza prevention.
Important note: AK0406 remains investigational. FDA IND clearance permits clinical investigation and does not mean the candidate has been approved for marketing or proven effective for influenza prevention in humans.
