South Korea's Hyundai Bioscience reported an Ebola virus IC50 of 0.125 μM for its broad-spectrum antiviral candidate Xafty (niclosamide), according to a company press release. The figure is approximately 2.2-fold lower than the 0.28 μM IC50 the company has previously reported for SARS-CoV-2, which Hyundai Bioscience said supports consideration of Xafty for use in the current Ebola outbreak.
The potency comparison is based on in vitro antiviral assay data, the company said, though the press release does not disclose the cell line, viral strain, multiplicity of infection, assay readout, replicate count, or statistical parameters underlying either IC50 figure. No animal efficacy data for Ebola were reported, and no clinical trial identifier for an Ebola program was provided. The company did not disclose whether an investigational new drug application or equivalent regulatory filing has been submitted or is planned for this indication.
Hyundai Bioscience cited human safety data from a completed COVID-19 Phase II/III study and an ongoing dengue Phase II/III trial in Vietnam as the basis for arguing that Xafty could be deployed rapidly. The company said no severe adverse events had been reported across dosage groups in those programs. Davey Smith, a virologist at the University of California San Diego, was quoted in the release stating that IC50 is a key indicator for estimating clinical efficacy and that Xafty, having demonstrated safety in humans, should be strongly considered for Ebola. The release did not include peer-reviewed data, a published study, or a clinical trial registry entry for Ebola.