Traws Advances Preclinical Oral Antiviral Program for Hantavirus, Ebola

Traws Pharma said it is advancing an unnamed proprietary oral combination antiviral program intended for hantavirus and Ebola outbreaks, with additional proposed activity against Lassa fever.

According to Traws, the investigational combination is designed to pair host nucleotide depletion with a nucleoside-mimic antiviral. The company describes the approach as a “dual-strike” mechanism: 1 component reduces intracellular nucleotide pools, while the other provides nucleoside analog substrates intended to interfere with viral RNA-dependent RNA polymerase activity.¹

“By aggressively reducing the intracellular competition between natural nucleotides and the active drug, this mechanism drastically lowers the effective concentration (IC90) of the nucleoside prodrug required to completely halt replication,” C. David Pauza, PhD, chief science officer of Traws Pharma, said in the company announcement.¹ Both components of the combination have previously been evaluated in human studies as single agents, and this program remains preclinical.

Traws said it is evaluating the combination in validated animal models of hantavirus and Ebola virus disease, with studies planned in biosafety level 3 and biosafety level 4 laboratories.¹ No animal efficacy results, pharmacokinetic data, resistance data, or human efficacy outcomes were reported in the announcement.

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The company also said it plans interactions with the US Centers for Disease Control and Prevention and has ongoing discussions with Nigeria’s National Agency for Food and Drug Administration and Control and the African Medicines Agency regarding clinical development, emergency manufacturing scale-up, and access planning.

Clinical Context

Hantaviruses are negative-sense RNA viruses that can cause hemorrhagic fever with renal syndrome or hantavirus pulmonary syndrome, depending on the viral species and geographic region. Management is largely supportive, with clinical outcomes influenced by early recognition, hemodynamic support, respiratory support, and critical care capacity.² No broadly approved oral antiviral is available for the routine treatment of hantavirus disease.

Ebola virus disease remains a high-consequence infection requiring rapid diagnosis, isolation, supportive care, and access to effective therapeutics when available. The PALM trial in the Democratic Republic of Congo showed improved survival with the monoclonal antibody therapies mAb114 and REGN-EB3 compared with ZMapp or remdesivir in patients with Ebola virus disease.³ WHO guidelines now recommend monoclonal antibody treatment for Ebola virus disease caused by Zaire ebolavirus, while emphasizing supportive care and outbreak response infrastructure.⁴

Against that backdrop, an oral broad-spectrum antiviral could be clinically relevant if it demonstrates efficacy, acceptable safety, and practical deployability in outbreak settings. However, Traws has not yet reported the data needed to establish those attributes.

Drug-Class Background

The proposed strategy combines a host-targeted component with a nucleoside antiviral concept. Nucleoside or nucleotide analogs have been used across multiple viral infections, but their clinical utility depends on adequate intracellular activation, antiviral selectivity, exposure at the site of infection, and tolerability. Host-targeted approaches may offer a theoretical barrier to resistance but can also raise safety concerns because the targeted pathways may be important for normal cellular function.

Traws’ broader pipeline includes oral small-molecule antivirals for respiratory viral diseases, including tivoxavir marboxil for influenza prevention and treatment, according to the company.¹ The hantavirus/Ebola/Lassa program appears separate from the lead influenza program.

Interpretation and Next Steps

For clinicians, the main takeaway is that this is an early-stage antiviral development announcement rather than evidence supporting clinical use. The most important next steps will be disclosure of the active components, preclinical efficacy in relevant animal models, toxicology results for the combination, and a defined regulatory pathway for first-in-human or emergency-use studies.

Key unanswered questions include whether nucleotide depletion can be achieved at antiviral levels without clinically meaningful host toxicity, whether activity extends across hantavirus species or filoviruses, and whether an oral regimen can produce adequate exposure in severe disease. Until such data are available, current outbreak management remains grounded in public health containment, supportive care, and pathogen-specific therapies where evidence supports their use.

References

1. Traws Pharma. Traws Pharma announces antiviral program targeting ongoing hantavirus and Ebola virus disease outbreaks. GlobeNewswire. Published May 27, 2026. Accessed May 29, 2026. https://www.globenewswire.com/news-release/2026/05/27/3301975/0/en/traws-pharma-announces-antiviral-program-targeting-ongoing-hantavirus-and-ebola-virus-disease-outbreaks.html
2. Vaheri A, Strandin T, Hepojoki J, et al. Uncovering the mysteries of hantavirus infections. Nat Rev Microbiol. 2013;11(8):539-550. doi:10.1038/nrmicro3066
3. Mulangu S, Dodd LE, Davey RT Jr, et al. A randomized, controlled trial of Ebola virus disease therapeutics. N Engl J Med. 2019;381(24):2293-2303. doi:10.1056/NEJMoa1910993
4. World Health Organization. Therapeutics for Ebola Virus Disease. World Health Organization; 2022.