Hyundai Bioscience Reports Negative Genotoxicity Results for Antiviral Candidate ‘Zefty’

Hyundai Bioscience announced on May 22 that its antiviral candidate, Zefty, has cleared critical genotoxicity testing, showing no evidence of DNA damage even at doses significantly higher than those planned for clinical use. The company confirmed that its Good Laboratory Practice (GLP)-compliant micronucleus assay returned “negative” results, a key regulatory milestone required for advancing to international clinical trials for respiratory viral infections.

What do the genotoxicity results mean for Zefty?

The negative results indicate that the drug does not cause chromosomal damage or structural mutations in cells, according to the test data released by Hyundai Bioscience. In toxicology, a negative finding in a micronucleus test—which identifies substances that cause chromosomal breakage or loss—is a standard safety requirement for pharmaceutical development. The testing was conducted by DT&CRO, a certified non-clinical research organization, following guidelines established by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH).

How high was the dosage in the safety trials?

Researchers tested the drug at the maximum tolerated dose (MTD) of 1,000 mg/kg/day. When converted to a Human Equivalent Dose (HED) for a 60-kilogram adult, this equates to approximately 9,677 mg per day. Hyundai Bioscience reports that this dosage is 7.17 times higher than the maximum dose currently proposed for human clinical trials. By demonstrating a safety margin of nearly six times the intended clinical dose, the company aims to address potential regulatory concerns regarding the drug’s impact on host cell genetic integrity.

Why is this data important for the AIR-V clinical trial?

This preclinical evidence is a prerequisite for the company’s planned “basket” clinical trial for respiratory viruses (AIR-V), a model previously discussed with Dr. Davey Smith of the University of California, San Diego (UCSD) School of Medicine. Unlike traditional trials that target a single pathogen, the AIR-V model aims to treat multiple respiratory illnesses, such as COVID-19, influenza, and respiratory syncytial virus (RSV), regardless of the specific viral strain. Because the drug uses a host-cell-targeting mechanism—which aims to block viral replication without directly attacking the virus—demonstrating that the drug does not damage the host’s own DNA is essential for regulatory approval.

Current Status of Clinical Development

Hyundai Bioscience intends to use these non-clinical safety records, combined with previous data from a dengue fever study conducted in Vietnam, to finalize the timeline for its U.S. clinical trial entry. Company officials state that the confirmation of genetic safety serves as a “double safety” layer, supplementing earlier 13-week repeat-dose toxicity studies that established a No-Observed-Adverse-Effect Level (NOAEL). This sequence of testing is designed to meet the rigorous standards of global regulatory bodies, including the U.S. Food and Drug Administration (FDA), as the company prepares to initiate trials aimed at treating patients during the early, symptomatic stages of infection.

Key Details of the Safety Profile

• Test Type: GLP-compliant micronucleus assay.
• Safety Margin: Approximately 7-fold higher than the maximum proposed clinical dose.
• Regulatory Standard: Conducted in accordance with ICH guidelines.
• Objective: Validating the safety of host-cell-targeting antiviral mechanisms.

Disclaimer: This article is for informational purposes and does not constitute medical advice. Clinical trial results are subject to review by regulatory agencies, and the efficacy of any investigational drug remains to be proven in human trials.