FDA Greenlights HDT Bio's First-in-Class HDT-321 for the Prevention of Deadly Tick-Borne Disease

SEATTLE, Sept. 19, 2025 /PRNewswire/ -- HDT Bio Corporation, a U.S.-based clinical-stage biotechnology company advancing immune-enhancing solutions for global health, biodefense, and oncology, today announced that the U.S. Food and Drug Administration (FDA) has cleared its Investigational New Drug (IND) application for HDT-321. The product is a first-in-class prophylactic designed to protect against Crimean-Congo Hemorrhagic Fever (CCHF), a fast-spreading, often fatal, viral tick-borne disease recognized as a serious threat to national and global health.

HDT-321 was developed in collaboration with the National Institutes of Health's National Institute of Allergy and Infectious Diseases (NIH/ NIAID) and the University of Texas Medical Branch (UTMB). It is the first clinical-stage product targeting CCHF to use HDT Bio's immune stimulator platform. The formulation combines the company's proprietary LION^™ delivery system with new discoveries specific to CCHF. This same platform was tested in human subjects during HDT's COVID-19 program, HDT-301. Those trials showed strong immune activation and a favorable safety profile, resulting in regulatory emergency-use authorization of two vaccine products in India.

The development of HDT-321 is supported by the Medical CBRN Defense Consortium (MCDC) and the U.S. Department of Defense. This backing reflects the product's strategic relevance to national biodefense. In 2009, a U.S. soldier in Afghanistan died after contracting CCHF, and several hospital staff in Germany who treated that patient were also infected. The incident underscored the threat this virus poses to U.S. forces abroad.

Under a Cooperative Research and Development Agreement (CRADA) between NIAID and UTMB, pre-clinical testing of the vaccine against CCHF virus was conducted by the Laboratory of Virology at NIAID's Rocky Mountain Laboratories (RML) in Montana. There, researchers showed that HDT-321 could protect against CCHF in several animal models. RML is a state-of-the-art biomedical research facility designed to safely study serious pathogens such as CCHF virus. This work to develop a vaccine against CCHF demonstrates the Laboratory of Virology's and NIAID's mission to understand and prevent infectious disease threats.

"This IND clearance marks a major milestone for HDT Bio's ability to field homegrown, next-generation technologies against global biological threats," said Dr. Steve Reed, Chief Executive Officer of HDT Bio. "HDT-321 is a first-in-class product built on a best-in-class American platform. It is non-viral, scalable, deployable without cold-chain infrastructure, and, most importantly, the platform was well tolerated under previous clinical investigations. As the threat of CCHF expands, the U.S. will have a powerful tool in its arsenal to lead the world in preparedness."

A National Mandate and a Growing Global Threat
Tick-borne diseases have drawn bipartisan concern in recent years. That concern led to the Kay Hagan Tick Act, named for Congresswoman Kay Hagan, who died from a tick-borne virus in 2019. The law established a coordinated national strategy to address high-consequence pathogens like CCHF. The Trump administration has reinforced that commitment by prioritizing biodefense, domestic manufacturing, and rapid-response technologies. That focus aligns with HDT Bio's mission and highlights the importance of American-made, field-ready tools like HDT-321 in protecting public health and national security.

More about Crimean-Congo Hemorrhagic Fever
CCHF is a viral illness spread by ticks and contact with infected animals. Mortality rates can reach 40%. The NIAID agency within the U.S. Department of Health and Human Services lists the CCHF virus as a priority pathogen and an emerging infectious disease of concern. The Centers for Disease Control and Prevention classifies it as a potential bioterrorism agent and a "Select Agent" due to biosecurity risks. The World Health Organization considers it a top-priority pathogen because of its outbreak potential and the lack of approved treatments or vaccines.

CCHF is one of the most widespread viral hemorrhagic fevers in the world, and it continues to appear in new regions. In 2024 and 2025, confirmed cases in Portugal and Spain prompted the United Kingdom government to issue travel advisories. Climate change and expanding tick habitats are driving increased incidence across Eastern Europe, the Middle East, and Central Asia. These shifts raise concern about future outbreaks in the United States.

About HDT Bio
HDT Bio Corporation is a clinical-stage biotechnology company based in Seattle, Washington. Its mission is to develop innovative, U.S.-built immunotherapies and preventive technologies for cancer, infectious disease, and global health security. The company's proprietary platforms—including LION™ and self-replicating biologic constructs—enable a new class of scalable, field-ready solutions for high-burden and high-consequence threats. HDT Bio's work is supported by the Department of Defense and the National Institutes of Health. Its pipeline includes candidates for glioblastoma, HER2+ cancers, tuberculosis, and several emerging infectious diseases.

Learn more at www.hdt.bio

About UTMB
The University of Texas Medical Branch at Galveston (UTMB) is among the eight academic institutions and five health institutions of The University of Texas System (UT System). It is home to the only national laboratory in Texas, and one of only two in the nation dedicated to combatting infectious threats to health. The Galveston National Laboratory (GNL) is a National Institutes of Health (NIH)-funded biocontainment facility that was dedicated on the UTMB campus in November 2008. The laboratory serves as a national resource in support of NIH's biodefense and emerging infectious diseases research agenda and stands ready to assist local, state, and national public health efforts in the event of a public health emergency.

The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government and reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not constitute or imply its endorsement, recommendation, or favoring by the U.S. Government and shall not be used for advertising or product endorsement purposes. The U.S. Government is authorized to reproduce and distribute reprints for Governmental purposes, notwithstanding any copyright notation thereon.

Effort sponsored by the U.S. Government under Other Transaction number W15QKN-16-9-1002 between the MCDC, the Government, and UTMB (under MCDC2204-011 contract to Dr. Thomas Geisbert, UTMB).

Contact: info@hdt.bio 

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SOURCE HDT Bio Corp.