Newtown, Pa.-based Traws Pharma Inc. on Monday reported that a single dose of its tivoxavir marboxil produced positive topline results from ferrets infected with H5N1 bird flu.
“We believe safe and effective antiviral drugs will be a critical component in the response to bird flu and that the development and testing of tivoxavir marboxil could be an important step to achieving that goal,” said Dr. Robert Redfield, chief medical officer for Traws Pharma and a former director of the U.S. Centers for Disease Control and Prevention. “The spread of bird flu in animals and increasing numbers of human exposures underscore the pressing need for effective medical countermeasures.”
Ferrets, an accepted animal model for human influenza, were given a single dose of tivoxavir marboxil as a treatment for bird flu, which was isolated from a Texas dairy worker. The subsequent studies evaluated the efficacy of the drugs, according to Traws Pharma.
“Topline data from the ferret model testing show that tivoxavir marboxil has the potential to inhibit disease after bird flu infection,” said C. David Pauza, chief science officer for Traws Pharma.
The company, a clinical-stage biopharmaceutical company developing oral small molecule therapies for the treatment of respiratory viral diseases, said the data are consistent with results reported in December 2024 in a murine model.
“The ferret challenge study builds on the robust protection from bird flu that we observed in a murine model and broadens our understanding of the disease process and the likely range of human doses that will be needed for treatment,” Pauza said. “We are conducting a similar challenge study in non-human primates, with data expected in Q1 2025.”
According to the results, substantial changes in disease progression were observed after a single oral dose of tivoxavir marboxil in the ferret model of bird flu using the A/Texas/37/2024 H5N1 virus. A lethal challenge in ferrets showed that tivoxavir marboxil increased the proportion of surviving animals and lowered the viral burden in the lungs and nasal tissues, the company said.
“We are witnessing a steady increase in the spread of bird flu,” Redfield said. “Dramatic increases in the number of infected poultry and dairy cattle, with increasing numbers of human exposures, including one fatal case in the USA, confirm the ongoing threat of bird flu and the increasing risk for wider spread in the human population.”
Traws Pharma CEO Werner Cautreels noted that with the non-human primate data in hand, the company now intends to approach the U.S. Food and Drug Administration (FDA) to discuss an accelerated approval under the FDA’s Animal Rule, a regulation that allows animal studies to be used to approve drugs and biological products. The rule is used when human clinical trials are not ethical or feasible.
“We plan to host a virtual investor update on March 31 to provide a detailed review of the bird flu program,” said Cautreels.