Traws Pharma Announces Progress in Developing Tivoxavir Marboxil for H5N1 Bird Flu

Investigational agent in development for treatment or prevention of H5N1 Bird Flu

Phase 1 dosing completed in healthy volunteers 

 Potent inhibition of drug-resistant and bird flu viruses in vitro

In vivo study in mice, with H5N1 isolated from an infected dairy worker, showed potent protection and suppression of virus replication in lungs

Phase 2 study expected to begin in H1 2025

Traws Pharma is expanding its influenza program to address the potential threat of bird flu

NEWTOWN, Pa., Dec. 23, 2024 /PRNewswire/ -- Traws Pharma, Inc. (NASDAQ: TRAW) ("Traws Pharma", "Traws" or "the Company"), a clinical-stage biopharmaceutical company developing oral small molecule therapies for the treatment of respiratory viral diseases, today announced progress in the development of its investigational one-dose influenza (flu) 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, MD, Chief Medical Officer for Traws Pharma and former Director of the U.S. Centers for Disease Control and Prevention (CDC). "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, PhD, 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 quantitation¹. 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 days¹, with topline data for a higher dose still to come," said Werner Cautreels, PhD, 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."

Topline Phase 1 Results with Tivoxavir Marboxil
The Phase 1 trial was a randomized, double-blind, placebo-controlled study to assess the safety, tolerability, and pharmacokinetics (PK) 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 twenty-three 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.

About H5N1 Bird Flu

The virus, also known as Type A H5N1 was detected for the first time in U.S. dairy cattle in March 2024. Since then, bird flu has been confirmed in at least 866 herds in 16 states. More than 60 people in eight states have been infected according to the U.S. Centers for Disease Control and Prevention. Health officials confirmed in December 2024 the first known severe illness in the U.S. caused by bird flu⁷. The California governor declared a state of emergency as the virus rampages through dairy cattle in that state^8.

About Tivoxavir Marboxil
Seasonal influenza is estimated to represent a multi-billion antiviral market opportunity, largely driven by global health organizations, practice guidelines and government tenders¹, with upside potential from pandemic flu outbreaks. Tivoxavir marboxil (also known as AV5124 or TRX-100) was designed as an inhibitor of the highly conserved influenza protein, CAP-dependent endonuclease (CEN). It has demonstrated potent in vitro activity against a range of influenza strains, including the highly pathogenic avian flu, in preclinical studies. The drug candidate's Phase 1 pharmacokinetic (PK) profile in healthy subjects, including the ability to achieve plasma levels that are consistently above the EC₉₀ (as determined in laboratory studies), for more than twenty-three days with higher dose data to come, may enable a single dose prophylaxis regimen. These data, combined with good overall tolerability results in healthy subjects and prevention of lethal influenza in an animal model, support further development of tivoxavir marboxil as a one-time treatment for influenza.

Source information:

1. TRAW data on file
2. Flu is burdensome
3. Flu hospitalizations 
4. Flu mortality
5. Flu in older adults 
6. Avian flu
7. Bird flu CDC
8. California

About Traws Pharma, Inc. Antiviral Program
Traws Pharma is a clinical stage biopharmaceutical company developing potential oral small molecule therapies for the treatment of respiratory viral diseases. The viral respiratory disease program includes two oral, novel, Phase 1, potentially best-in-class, small molecule drug candidates: tivoxavir marboxil, in development for flu and pandemic flu, targeting the influenza cap-dependent endonuclease (CEN); and ratutrelvir, in development as a COVID treatment, targeting the Mpro (3CL protease), without the need for co-administration of ritonavir.

Traws Pharma is committed to delivering novel compounds for unmet medical needs using state-of-the-art drug development technology. With a focus on product safety and a commitment to patients in need that are specifically vulnerable, we aim to build solutions for important medical challenges and alleviate the burden of viral infections

Forward-Looking Statements 

Some of the statements in this release are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, Section 21E of the Securities Exchange Act of 1934, as amended, and the Private Securities Litigation Reform Act of 1995, and involve risks and uncertainties including statements regarding the Company, its business and product candidates, including the potential opportunity, benefits and the regulatory plans for tivoxavir marboxil. The Company has attempted to identify forward-looking statements by terminology including "believes", "estimates", "anticipates", "expects", "plans", "intends", "may", "could", "might", "will", "should", "preliminary", "encouraging", "approximately" or other words that convey uncertainty of future events or outcomes. Although Traws believes that the expectations reflected in such forward-looking statements are reasonable as of the date made, expectations may prove to have been materially different from the results expressed or implied by such forward looking statements. These statements are only predictions and involve known and unknown risks, uncertainties, and other factors, including the success and timing of Traws' clinical trials, collaborations, market conditions and those discussed under the heading "Risk Factors" in Traws' filings with the U.S. Securities and Exchange Commission (SEC). Any forward-looking statements contained in this release speak only as of its date. Traws undertakes no obligation to update any forward-looking statements contained in this release to reflect events or circumstances occurring after its date or to reflect the occurrence of unanticipated events.

Traws Pharma Contacts:

Mark Guerin
Traws Pharma, Inc.
267-759-3680
www.trawspharma.com

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SOURCE Traws Pharma, Inc.