Traws Pharma Inc., a clinical-stage biopharmaceutical company developing oral small molecule therapies for the treatment of respiratory viral diseases, is announcing progress in the development of its investigational one-dose influenza investigational therapy, tivoxavir marboxil for treatment of H5N1 bird flu.

"The spread of avian influenza in wild and domestic animal populations including mammals, brings increasing risk for adaptation to humans and subsequent spread in the population" said Robert R. Redfield, chief medical officer for Traws Pharma and former director of the U.S. Centers for Disease Control and Prevention. "Bird flu is an occupational hazard for poultry and dairy workers. With increasing numbers of human infections and recent reports of severe cases, we should be alert to the rising potential for epidemic or pandemic spread of bird flu."

"In laboratory testing, tivoxavir marboxil inhibited multiple isolates of highly pathogenic avian influenza H5N1. We evaluated the effects of drug treatment in mice exposed to human H5N1, where the virus was isolated from a dairy worker exposed to infected cattle," said C. David Pauza, chief science officer for Traws Pharma. "Oral treatment with tivoxavir marboxil after the virus infection resulted in complete survival and lung virus levels below the limit of quantitation. This result is highly encouraging for future clinical development of tivoxavir marboxil for treating human H5N1 influenza."

"Current topline data from our Phase I clinical trial demonstrated safety and tolerability of tivoxavir marboxil, and maintenance of drug levels in blood above the EC₉₀ for longer than 23 days, with topline data for a higher dose still to come," said Werner Cautreels, chief executive officer of Traws Pharma. "In addition, the potential for tivoxavir marboxil as a treatment for H5N1 bird flu was demonstrated in an animal model."

The Phase 1 trial was a randomized, double-blind, placebo-controlled study to assess the safety, tolerability and pharmacokinetics of ascending doses for one-time tivoxavir marboxil treatment in healthy, influenza-negative, adult volunteers. 

No treatment-related adverse events were reported during the Phase 1 study. Current topline data from this study showed that a single dose of tivoxavir marboxil maintained plasma drug levels consistently above the EC₉₀ for more than 23 days, with topline data for a higher dose still to come. Preclinical studies showed that tivoxavir marboxil demonstrated potent inhibition of drug-resistant influenza viruses, as well as potent inhibition of highly pathogenic bird flu viruses¹ both in vitro and in vivo.

Source: Traws Pharma Inc.