Shanghai Ark Biopharmaceutical (ArkBio) has announced that the US Food and Drug Administration (FDA) has granted its Investigational New Drug (IND) application for AK0406, a long-acting Antiviral drug-Fc Conjugate (AFC), enabling the company to initiate a phase 2 clinical trial for influenza prevention in general population in the US.

Seasonal vaccination remains central to influenza prevention. However, changes in circulating influenza viruses and variability in individual immune response can limit vaccine protection, particularly among older adults and people who are immunocompromised. Additional preventive approaches could help address these unmet needs.

According to the US Centers for Disease Control and Prevention (CDC), despite the availability of influenza vaccines, the 2025-2026 influenza season resulted in at least 32 million illnesses, 380,000 hospitalisations and 24,000 deaths in the US.

AK0406 is a novel AFC drug discovered and developed by ArkBio.

By precisely conjugating multiple potent small-molecular antivirals to an antibody Fc domain, AK0406 is designed to combine direct antiviral activity with Fc-mediated immune clearance to prevent influenza, with potential therapeutic applications.

In preclinical studies, AK0406 demonstrated broad-spectrum and highly potent antiviral activity against both influenza A and B strains. It has also been optimised for its pharmacokinetics (PK) properties and Good Manufacturing Practice (GMP) process.

In February 2026, AK0406 received approval from a Human Research Ethics Committee (HREC) in Australia to initiate a phase 1 clinical trial. In July 2026, ArkBio announced that enrollment and dosing of healthy adult participants had been completed across all cohorts and that the study had entered the follow-up phase.

In August 2026, National Medical Products Administration (NMPA) of China cleared the IND application for AK0406 for influenza prevention. The FDA clearance marks a further milestone in the global clinical development of AK0406.

The US phase 2 clinical trial will be a multicenter, randomised, double-blind, placebo-controlled study in adults during an influenza season. Its primary objective is to evaluate AK0406 for influenza prevention. The study will also assess safety, tolerability, PK and immunogenicity. The resulting data will inform AK0406's future global development strategy.

ArkBio plans to continue discussions with the FDA and the Center for Drug Evaluation (CDE) of China's NMPA to advance phase 2 development in the US and China. Through parallel development pathways, the company aims to accelerate the AK0406 program as an additional option for influenza prevention, addressing challenges posed by viral evolution and limited vaccine protection, including in populations at high-risk of severe disease.