aibioTraws Pharma defers TXM challenge study after negative MHRA review
Tickers TRAW
Traws says a negative review by the UK regulator has deferred its planned Phase 2a influenza challenge study, and that it is advancing backup influenza compounds.
Key facts
- Company
- Traws Pharma, Inc. (NASDAQ: TRAW)
- News type
- Company Updates
- Primary source
- Traws Pharma, Inc. SEC filing (Form 8-K)
Traws Pharma, Inc. (NASDAQ: TRAW) said on June 12, 2026 that the planned test of tivoxavir marboxil (TXM) in a Phase 2a human influenza challenge study has been deferred. The reason is a negative review of the program by the UK's Medicines and Healthcare products Regulatory Agency (MHRA). The press release describes the setback as affecting the timing of the study.
The regulatory setback
Chief Executive Officer Iain Dukes said: "While the recent regulatory feedback affects the timing of our planned challenge study, it does not change our conviction in the underlying scientific rationale." He said the company is advancing alternative candidates designed to keep TXM's pharmacokinetics and efficacy while excluding potential regulatory concerns.
The release does not say what the MHRA's concerns were, though it says the backup compounds are free of mutagenic potential. Chief Science Officer C. David Pauza, PhD, said that "Tivoxavir marboxil demonstrated potent efficacy in three animal models of highly pathogenic avian influenza and a pharmacokinetic profile consistent with its use for bird flu treatment and prevention." He said the product candidate retains potential for emergency use in a bird flu outbreak and for prevention in high-risk populations.
Backup compounds
Traws said it has a portfolio of back-up influenza antiviral compounds and is actively advancing candidates that carry TXM's long-duration pharmacokinetic and antiviral profile. The company describes those candidates as devoid of any mutagenic potential. Dukes said the company remains committed to long-acting influenza antivirals and continues to believe the modality has meaningful potential in seasonal influenza prophylaxis.
The release calls the influenza program a high priority. Chief Medical Officer Robert R. Redfield, MD, a former head of the U.S. Centers for Disease Control and Prevention, said treatment and prevention are especially important for elderly and immunocompromised people, who are at much greater risk of severe influenza than the general population.
Company background
Traws, formerly Onconova Therapeutics, Inc., merged with Trawsfynydd Therapeutics, Inc. on April 1, 2024, and expanded its focus from cancer to respiratory viral diseases. Its four clinical programs are TXM, ratutrelvir, narazaciclib (ON 123300) and rigosertib. TXM is an investigational oral, small molecule cap-dependent endonuclease inhibitor. The company's annual report says the goal is to develop it as a single-dose therapy for bird flu and seasonal influenza, and as a once-monthly oral drug for influenza prevention.
The annual report describes a first-in-man study in Russia that ran from May to September 2023 and enrolled 28 healthy males. A Traws-sponsored Phase 1 study in Australia enrolled four cohorts of eight participants. The company reported good overall tolerability in that study and said a single dose maintained detectable plasma drug levels for 23 days. In 2025, the annual report says, TXM significantly reduced disease progression and increased survival in mice, ferrets and nonhuman primates infected with an H5N1 virus. The Phase 1 doses in Australia were 80, 120, 240 and 480 mg.
Financial position
The XBRL financial data for the company show 2025 revenue of $2.8 million and net income of $9.2 million, with cash used in operations of $18.2 million. For 2024, revenue was $226,000, the net loss was $166.5 million and cash used in operations was $29.8 million.
Dukes said the company's cash runway extends to the first quarter of 2027. The release does not give a new date for the challenge study.
The release's own word for the event is a setback, and it is the lead drug. The backup compounds are not named, have no human data and would start well behind TXM, so the influenza program's timeline is open. The animal results are the company's, and animals are not people. The runway runs only to early 2027 and the company used $18.2 million of cash in operations in 2025, so it will likely need to sell more shares, with dilution, before any influenza data arrive. The 2025 net income of $9.2 million does not change that, because cash from operations was negative.