VALION BIO RECEIVES FIRST FDA-PRECEDENT STUDY PROTOCOL FROM NIAID FOR ENTOLIMOD™; FEDERAL AGENCY TO FULLY FUND BLA-ENABLING IN VIVO PROGRAM AND CO-NAVIGATE FDA SUBMISSION

Initial Study to Evaluate Entolimod™ for Gastrointestinal Tissue Preservation in Partial-Body Acute Radiation Syndrome — an Indication for Which No Currently Approved or Stockpiled Countermeasure Has Demonstrated Efficacy

SAN ANTONIO, May 5, 2026 /PRNewswire/ -- Valion Bio, Inc. (Nasdaq: VBIO) (formerly Tivic Health Systems, Inc.), a clinical-stage immunotherapeutics company developing Entolimod™ for Acute Radiation Syndrome (ARS) and oncology supportive care, today announced it has received the first study protocol under its previously announced non-clinical evaluation agreement with the National Institute of Allergy and Infectious Diseases (NIAID), a component of the National Institutes of Health. Under the agreement — valued at up to $7 million — NIAID will fully fund the in vivo studies required to support the Company's Biologics License Application (BLA) for Entolimod™ under the FDA's Animal Rule pathway, with the agency further committed to co-navigate the FDA submission process alongside Valion Bio upon favorable study outcomes.

The protocol provided to Valion Bio is identical to a study design previously used and accepted by the FDA in support of a prior ARS medical countermeasure approval. This regulatory precedent meaningfully de-risks the design phase of the Company's BLA-enabling work, as the agency has already accepted the structure as evidentiary under the Animal Rule. The studies will be conducted at the Armed Forces Radiobiology Research Institute (AFRRI), the U.S. government's primary radiological research facility for ARS countermeasure evaluation, with NIAID serving as the contracting and funding agency.

Initial Study Targets Indication No Stockpiled Drug Currently Addresses

The first study under the protocol is a Partial-Body Irradiation Gastrointestinal Acute Radiation Syndrome (PBI-GI-ARS) pilot designed specifically to evaluate Entolimod's ability to preserve gastrointestinal tissue — including intestinal crypt cells and endothelial cells — following radiation exposure. No countermeasure currently approved by the FDA or held in the U.S. Strategic National Stockpile has demonstrated GI-tract preservation under this protocol. In real-world radiation exposure scenarios — including dirty-bomb events, nuclear reactor incidents, partial detonations, and special-operations exposures involving directional radiation sources — partial-body irradiation is the predominant injury pattern. Bone marrow is often partially shielded; the GI tract typically is not. GI failure can result in death within 24–48 hours due to loss of nutrient and water absorption, irrespective of hematopoietic function. A positive signal in this pilot would position Entolimod™ as the only medical countermeasure capable of demonstrating both hematopoietic and gastrointestinal protection — addressing the full lethal radiation injury cascade currently uncovered by stockpiled agents including Neupogen® (filgrastim), Neulasta® (pegfilgrastim), and Leukine® (sargramostim).

"This is not a grant application waiting on a decision — the federal government is actively funding the science, providing an FDA-precedent protocol, and committing to walk our submission into the agency alongside us," said Michael K. Handley, Chief Executive Officer of Valion Bio. "When NIAID provides both the capital and the regulatory institutional knowledge to advance a program, that is a materially different risk profile than a company-sponsored study. It is, in effect, money plus knowledge — and it is the combination that historically separates programs that reach approval from those that do not."

The NIAID-funded program covers all in vivo testing remaining on the critical path to BLA filing, including bridging studies designed to confirm that Entolimod™ manufactured at Velocity Bioworks, Valion Bio's wholly owned CDMO subsidiary in San Antonio, is equivalent to drug material previously evaluated. Entolimod™ has been administered in 42 non-human primate studies and to approximately 300 human subjects, with over $140 million invested in the program to date, including approximately $35.6 million in prior U.S. government funding.

Entolimod™ has received FDA Fast Track and Orphan Drug designations for ARS and is being developed under the Animal Rule pathway, which permits approval based on animal efficacy data when human efficacy trials are not feasible or ethical. Its mechanism — TLR5 agonism driving NF-κB-mediated cytokine induction in parallel with PI3K/AKT anti-apoptotic signaling — is differentiated from currently stockpiled G-CSF agents in that it is designed to protect both hematopoietic and gastrointestinal tissues across the full lethal-dose range of radiation exposure.

"The capital we had planned to deploy on this program — approximately $7 million — can now be redirected toward advancing Entolasta™, our second-generation molecule, into clinical development," Mr. Handley continued. "We are advancing on parallel fronts: our BLA-enabling program for Entolimod™ is now government-funded and government-supported at the regulatory level, our second-generation asset is gaining real momentum, and our commercial pipeline in oncology supportive care continues to mature. These are not competing priorities — they are compounding ones."

ABOUT VALION BIO, INC.
Valion Bio, Inc. (formerly Tivic Health Systems, Inc.) (Nasdaq: VBIO) is a clinical-stage immunotherapeutics company developing Entolimod™, a TLR5 agonist, for Acute Radiation Syndrome (ARS), oncology supportive care, and longevity indications. Entolimod™ for ARS has received Fast Track and Orphan Drug designations from the U.S. Food and Drug Administration. Valion Bio is also advancing Entolasta™, a next-generation TLR5 agonist designed for potential broader therapeutic applications, including oncology supportive care. The Company'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. Valion Bio's wholly owned subsidiary, Velocity Bioworks, is a full-service contract development manufacturing organization (CDMO) offering biomanufacturing services to third-party biotech companies. Valion Bio 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 www.valionbio.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 Valion Bio, 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, NIAID, 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; 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™; the company's ability to successfully commercialize its product candidates in the future; 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, see Valion Bio's filings with the SEC, including its Annual Report on Form 10-K for the year ended December 31, 2025, filed with the SEC on March 30, 2026, 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 & MEDIA CONTACT
Rich Cockrell
CG Capital
[email protected] 

SOURCE Tivic Health Systems, Inc.