Armed Forces Radiobiology Research Institute (AFRRI) Will Conduct the Gastrointestinal Acute Radiation Syndrome (GI-ARS) Study

SAN ANTONIO, TX / ACCESS Newswire / March 26, 2026 / Tivic Health Systems Inc. (Nasdaq:TIVC), a clinical-stage immunotherapeutics company, today announced it has entered into an agreement with the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, to sponsor and conduct a series of preclinical studies evaluating Entolimod™ for gastrointestinal acute radiation syndrome (GI-ARS).

The program is expected to support Tivic's development strategy for Entolimod™ as a medical countermeasure for acute radiation syndrome (ARS).

Under the agreement, NIAID will fund and conduct GI-ARS studies, the first of which will be performed at the Armed Forces Radiobiology Research Institute (AFRRI). The study is designed to evaluate Entolimod's ability to protect GI tissue and mitigate radiation-induced mucosal necrosis following exposure to lethal radiation doses, an area with limited therapeutic options, and a major driver of mortality in ARS.

The research will begin with mouse models and may advance to non-human primate studies provided the initial studies demonstrate efficacy. These preclinical studies are typically required to support regulatory approval under the FDA's Animal Rule.

Tivic Health will be utilizing the non-clinical and pre-clinical services program offered by the National Institute of Allergy and Infectious Diseases. Importantly, NIAID will cover all study-related costs, providing Tivic with access to advanced preclinical development infrastructure without incremental capital requirements.

"Government-sponsored development of Entolimod represents an important step forward in addressing a critical gap in the treatment of acute radiation syndrome," said Michael K. Handley, chief executive officer of Tivic Health. "Currently approved therapies primarily target the hematopoietic component of ARS, while gastrointestinal injury remains a significant unmet need. We believe Entolimod's mechanism, which activates innate immune pathways to protect multiple tissue types, may offer a differentiated approach. These studies are expected to further define its potential and support our targeted BLA submission."

Currently approved ARS therapies, including granulocyte colony-stimulating factors such as Neupogen® (filgrastim), Neulasta® (pegfilgrastim), and Leukine® (sargramostim), are designed to stimulate recovery of the hematopoietic system following radiation exposure. However, damage to the GI tract is a key determinant of survival at higher radiation doses and is not directly addressed by these agents.

Entolimod is a Toll-like receptor 5 (TLR5) agonist that activates NF-κB signaling pathways, with preclinical data suggesting potential to protect epithelial and other tissues from radiation-induced damage. This differentiated mechanism may enable a broader cytoprotective effect across multiple organ systems, including the gastrointestinal tract.

Strategic and Competitive Positioning

• Addresses GI-ARS: Seeks to address a major unmet need not directly addressed by currently approved therapies

• Differentiated mechanism: TLR5 agonist activates innate immune pathways for multi-tissue protection

• Capital efficiency: NIAID-funded development program creates non-dilutive support thereby reducing company development costs

• Regulatory pathway: Designed to support approval under the FDA's Animal Rule

• BLA trajectory: Supports an expedited BLA submission

About Tivic

Tivic Health is developing biologics that activate innate immune pathways for cytoprotection and modulate immune responses in conditions driven by radiation, disease, and immune dysregulation. The company's lead candidate, Entolimod™ for acute radiation syndrome (ARS), has been extensively studied having demonstrated survival benefits and improved tissue recovery in animal models under the FDA's Animal Rule.

Entolimod™ is a novel Toll-like receptor 5 (TLR5) agonist that activates NF-κB signaling pathways to protect cells from damage and stimulate immune responses. Entolimod™ for ARS has received Fast Track and Orphan Drug designations from the U.S. Food and Drug Administration.

Tivic is also advancing Entolasta™, a next-generation TLR5 agonist designed for potential broader therapeutic applications, including oncology supportive care. Tivic's clinical pipeline includes potential treatments for neutropenia, which is most commonly caused by chemotherapy, and a state of T-cell dysfunction known as lymphocyte exhaustion.

Tivic's wholly owned subsidiary, Velocity Bioworks, is a full-service contract development manufacturing organization, (CDMO) offering biomanufacturing services to third-party biotech companies. Tivic also leverages Velocity Bioworks' manufacturing capabilities to advance its own drug pipeline with the expected benefits of lower costs, accelerated manufacturing outcomes and supply chain security. For more information, visit https://ir.tivichealth.com.

Forward-Looking Statements

This press release may contain "forward-looking statements" that are subject to substantial risks and uncertainties. All statements, other than statements of historical fact, contained in this press release are forward-looking statements. Forward-looking statements contained in this press release may be identified by the use of words such as "anticipate," "believe," "contemplate," "could," "estimate," "expect," "intend," "seek," "may," "might," "plan," "potential," "predict," "project," "target," "aim, "should," "will," "would," or the negative of these words or other similar expressions, although not all forward-looking statements contain these words. Forward-looking statements are based on Tivic Health Systems Inc.'s current expectations and are subject to inherent uncertainties, risks, and assumptions that are difficult to predict. Further, certain forward-looking statements are based on assumptions as to future events that may not prove to be accurate, including as a result of the company's interactions with and guidance from the FDA and other regulatory authorities; the continued interest of BARDA and other U.S. government agencies in Entolimod; the ability of the company to achieve the expected benefits from the acquisition of development and manufacturing assets within expected time frames or at all; changes to the company's relationship with its partners; expectations regarding the potential benefits of the leadership transition; failure to obtain FDA or similar clearances or approvals and noncompliance with FDA or similar regulations, including related to the Animal Rule; the company's future development of Entolimod or Entolasta; changes to the company's business strategy; timing and success of pre-clinical and clinical trials and study results; regulatory requirements and pathways for approval; the company's ability to successfully commercialize its product candidates in the future; changes in the markets and industries in which the company does business; consummation of any strategic transactions; the company's need for, and ability to secure when needed, additional working capital; the company's ability to maintain its Nasdaq listing; and changes in tariffs, inflation, legal, regulatory, political and economic risks. Accordingly, you are cautioned not to place undue reliance on such forward-looking statements. For a discussion of risks and uncertainties relevant to the company, and other important factors, see Tivic Health's filings with the SEC, including, its Annual Report on Form 10-K for the year ended December 31, 2024, filed with the SEC on March 21, 2025, under the heading "Risk Factors", as well as the company's subsequent filings with the SEC. Forward-looking statements contained in this press release are made as of this date, and the company undertakes no duty to update such information except as required by applicable law.

Investor Contact:

Hanover International, Inc.
ir@tivichealth.com

Media Contact:

DJ Freyman
DJ@FastrackPR.com

SOURCE: Tivic Health Systems