AFRRI/NIAID Designs Proprietary PBI-BM2.5 Protocol to Evaluate Valion Bio's (NASDAQ: VBIO) Entolimod as the First and Only Treatment for GI-ARS

Rhea-AI Summary

Valion Bio (NASDAQ:VBIO) announced that AFRRI, in partnership with NIAID, has finalized a proprietary PBI-BM2.5 survival efficacy protocol to evaluate Entolimod for treating gastrointestinal acute radiation syndrome (GI-ARS).

The murine model meets FDA Animal Rule criteria. No FDA-approved GI-ARS countermeasures currently exist. The ARS market is estimated at $5.47B in 2025, growing to $7.80B by 2032.

Positive

• AFRRI/NIAID finalize PBI-BM2.5 survival protocol for Entolimod GI-ARS testing
• Protocol design aligned with FDA Animal Rule criteria for non-clinical efficacy
• Partnership with AFRRI/NIAID may derisk regulatory and commercial advancement
• Targets critical gap with no current FDA-approved GI-ARS countermeasures
• Addresses ARS market projected to reach $7.80B by 2032

Negative

• None.

News Market Reaction – VBIO

+6.93%

14 alerts

+6.93% Session close to close

+26.3% Peak Tracked

-8.2% Trough Tracked

$1.85M Market Cap

1.2x Rel. Volume

In the Jun 25 session, VBIO gained 6.93%, reflecting a notable positive market reaction. Argus tracked a peak move of +26.3% during that session. Argus tracked a trough of -8.2% from its starting point during tracking. Our momentum scanner triggered 14 alerts that day, indicating notable trading interest and price volatility.

Data tracked by StockTitan Argus on the day of publication.

Market Context

The stock moved +6.9% in the session following this news. A strong positive reaction aligns with VBI...

Analysis

The stock moved +6.9% in the session following this news. A strong positive reaction aligns with VBIO’s pre-news position near 55% below its 52-week high and repeated government-focused milestones. Investors may still weigh financing and execution risks as Entolimod advances under the FDA’s Animal Rule framework.

Key Figures

Bone marrow sparing: 2.5% Radiation dose: 14.6 Gy Market size 2025: $5.47 billion +5 more

8 metrics

Bone marrow sparing 2.5% PBI-BM2.5 murine model shielding of bone marrow

Radiation dose 14.6 Gy LD50/30 lethal radiation dose in PBI-BM2.5 murine model

Market size 2025 $5.47 billion Global ARS medical countermeasures market valuation by 2025

Market size 2032 $7.80 billion Projected ARS medical countermeasures market valuation by 2032

CAGR 5.2% Compound annual growth rate of ARS market 2025–2032

North America share 46% North American share of global ARS market revenue

Bone marrow spared 2.5% Single hind leg and tail shielded from lethal radiation dose

Pre-news price $0.54 VBIO last close before AFRRI/NIAID protocol announcement

Historical Context

5 past events · Latest: Jun 11 (Positive)

Pattern 5 events

Date	Event	Sentiment	24h Move	Catalyst
Jun 11	Government support update	Positive	-24.8%	House committee directive aligning with Entolimod’s prophylactic and therapeutic profile.
May 19	Government briefing	Positive	+2.9%	Briefing DoW and BARDA on Entolimod and prior U.S. funding support.
May 14	Platform license deal	Positive	-5.5%	Velocity Bioworks securing exclusive commercial license for BioScan-NMR platform.
May 14	Quarterly earnings	Negative	-5.5%	Q1 2026 results highlighting operating expenses, net loss, and cash position.
May 11	Earnings date announcement	Neutral	+15.6%	Scheduling and investor call details for upcoming Q1 2026 results.

24h Move is the share-price change in the day after each event; other market factors may also have contributed.

Pattern Detected

VBIO has shown mixed reactions, including sharp selloffs on otherwise constructive strategic and government-engagement news.

Key Terms

gi-ars, animal rule, partial body irradiation, ld50/30, +2 more

6 terms

gi-ars medical

"Entolimod™, for the treatment of Gastrointestinal Acute Radiation Syndrome ("GI-ARS")."

A severe form of acute radiation sickness that damages the lining of the stomach and intestines after high doses of ionizing radiation, causing pain, vomiting, diarrhea, dehydration and risk of fatal infection. Investors track GI-ARS because it drives demand for medical treatments, emergency countermeasures and government stockpiles; progress in effective therapies or regulatory clearances can create sizable markets and influence the valuation of biotech and defense contractors working on those solutions.

animal rule regulatory

"meets the FDA's Animal Rule criteria, which allows the Agency to approve new drugs"

A regulatory pathway that allows safety and effectiveness of drugs or vaccines to be judged primarily from well-controlled animal studies when human trials would be unethical or impossible, such as for treatments against rare, lethal exposures. It matters to investors because approval via this route can speed a product to market for urgent or niche needs but carries extra scientific and regulatory risk—think of it as accepting a high-quality dress rehearsal instead of a live show, with requirements for strong animal models and often additional post-approval obligations.

partial body irradiation medical

"partial body irradiation with 2.5% bone marrow sparing/shielding ("PBI-BM2.5") at lethal radiation dose"

Partial body irradiation is a medical treatment that directs controlled doses of radiation to a specific area of the body rather than the whole body, commonly used to shrink tumors, ease symptoms, or prepare a patient for procedures like transplants. For investors, it signals a focused clinical approach or product use that affects market size, regulatory review, clinical outcomes and reimbursement—think of it like targeting a single faulty pipe in a building rather than replacing the whole plumbing system.

ld50/30 medical

"PBI-BM2.5") at lethal radiation dose (LD50/30 of 14.6 Gy) murine model"

LD50/30 is a toxicology benchmark that measures the dose of a substance or exposure (such as a drug, chemical, or radiation) that is expected to kill 50% of a test population within 30 days. Think of it like a safety line drawn on a scale: it helps scientists and regulators compare how lethal different exposures are and set safe handling, labeling, or treatment limits. For investors, LD50/30 outcomes affect product risk profiles, liability estimates, regulatory hurdles, and potential marketability of treatments or chemicals.

tlr5 agonist medical

"where Entolimod's TLR5 agonist mechanism has the greatest potential to differentiate"

A TLR5 agonist is a molecule that activates the immune receptor TLR5, which detects bacterial flagellin and helps kick-start the body's defense response. Think of it like a fire alarm trigger that alerts and strengthens immune activity; in drugs and vaccines it can boost or direct immunity. Investors care because TLR5 agonists are a clear drug mechanism influencing clinical risk, regulatory review, safety, and market potential for vaccines and immunotherapies.

radiomitigant medical

"Entolimod, which has shown survival benefit as a radioprotectant and radiomitigant in non-human primate"

A radiomitigant is a medical drug or therapy given after someone has been exposed to harmful ionizing radiation to reduce damage and improve recovery; think of it as a treatment that limits the fallout after a spill rather than preventing the spill itself. Investors watch radiomitigants because their development, regulatory approval, stock value and commercial demand can be driven by nuclear accidents, military needs, emergency preparedness and use alongside cancer radiation treatment, creating distinct market and regulatory risk–reward dynamics.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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AFRRI/NIAID partnership and validated animal models significantly derisk regulatory and commercial advancement of Company's lead candidate

Positive momentum further positions Entolimod as a potential first and only treatment for GI-ARS, representing a multi-billion-dollar commercial opportunity

SAN ANTONIO, June 25, 2026 /PRNewswire/ -- Valion Bio, Inc. (Nasdaq: VBIO) ("Valion Bio" or the "Company") today announced that the Armed Forces Radiobiology Research Institute ("AFRRI"), a division of the U.S. Department of War ("DoW"), in partnership with the National Institute of Allergy and Infectious Diseases ("NIAID"), has completed design of the survival efficacy protocol that will be used to evaluate the Company's lead candidate, Entolimod™, for the treatment of Gastrointestinal Acute Radiation Syndrome ("GI-ARS").

The final AFRRI/NIAID protocol design for Entolimod emanates from the Company's previously announced non-clinical evaluation agreement with NIAID, and closely follows the U.S. House Armed Services Committee's direction to the DoW to develop a resources and fielding plan for prioritizing radiation/nuclear countermeasures that, like Entolimod, are both prophylactic (pre-exposure) and therapeutic (post-exposure).

Currently, no U.S. Food and Drug Administration ("FDA")-approved medical countermeasures exist to mitigate GI-ARS; representing a critical therapeutic and commercial gap in a market driven by U.S. government emergency preparedness requirements. The AFRRI/NIAID-selected partial body irradiation with 2.5% bone marrow sparing/shielding ("PBI-BM2.5") at lethal radiation dose (LD50/30 of 14.6 Gy) murine model to evaluate Entolimod is scientifically rigorous and meets the FDA's Animal Rule criteria, which allows the Agency to approve new drugs and biological products based on animal efficacy studies when human clinical trials are unethical or not feasible, such as in the case of internal radioactive contamination.^1,2,3

Entolimod is a recombinant deletion variant of Salmonella FliC flagellin engineered to activate TLR5 selectively. Upon engagement, Entolimod triggers specific pathways that ultimately promote multi-tissue cytoprotection and inhibit apoptosis in radiosensitive hematopoietic and gastrointestinal tissues. By utilizing a proprietary murine model that spares only 2.5% of bone marrow (one hind leg and tail) from a lethal radiation dose, the study will isolate GI pathophysiology from overwhelming hematopoietic failure — creating a cleaner efficacy signal for a mechanism targeting intestinal epithelial recovery and immune restoration.

Valion Bio CEO, Michael Handley, said, "The AFRRI protocol finalization represents a key inflection point for Entolimod as a radiation/nuclear countermeasure and for Valion as a company. We are now positioned to generate the high-quality non-clinical efficacy data that the FDA and the government require to support future licensure under the Animal Rule. The gastrointestinal subsyndrome of ARS is the market's greatest unmet need—it is lethal, it is currently untreated, and it is precisely where Entolimod's TLR5 agonist mechanism has the greatest potential to differentiate from incumbent G-CSF therapy."

This Entolimod protocol advancement comes as the broader ARS medical countermeasures market accelerates, with global market valuations reaching an estimated $5.47 billion by 2025 and projected to expand to $7.80 billion by 2032, growing at a compound annual growth rate of 5.2%. North America, where government stockpiling and biodefense spending concentrate, accounts for 46% of market revenue.⁴

Sources

¹ Vidya P. Kumar, Kefale Wuddie, Alena Tsioplaya, Alia Weaver, Gregory P. Holmes-Hampton, and Sanchita P. Ghosh "Development of a Multi-Organ Radiation Injury Model with Precise Dosimetry with Focus on GI-ARS," Radiation Research 201(1), 19-34, (28 November 2023). https://doi.org/10.1667/RADE-23-00068.1

² Krivokrysenko VI, Toshkov IA, Gleiberman AS, Krasnov P, Shyshynova I, Bespalov I, Maitra RK, Narizhneva NV, Singh VK, Whitnall MH, Purmal AA, Shakhov AN, Gudkov AV, Feinstein E "The Toll-Like Receptor 5 Agonist Entolimod Mitigates Lethal Acute Radiation Syndrome in Non-Human Primates," PLoS One (14 September 2015). https://doi.org/10.1371/journal.pone.0135388.

³ FDA "Animal Rule Information" https://www.fda.gov/emergency-preparedness-and-response/preparedness-research/animal-rule-information

⁴ CoherentMI "Acute Radiation Syndrome Market Size and Share Analysis – Growth Trends and Forecasts" ^{https://www.coherentmi.com/industry-reports/acute-radiation-syndrome-market}

About Valion Bio, Inc.

Valion Bio, Inc. (Nasdaq: VBIO), the new corporate identity of Tivic Health Systems, Inc., 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 and has 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. Valion Bio is also advancing Entolasta, a next-generation TLR5 agonist designed for potential broader therapeutic applications, including oncology supportive care. Valion Bio's wholly owned subsidiary, Velocity Bioworks, a contract development and manufacturing organization (CDMO), currently provides biomanufacturing services to Valion, and is working towards providing services to third-party biotech companies in the future. 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," "con template," "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 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; 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 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

vbio@cg.capital

404.736.3838

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SOURCE Valion Bio, Inc.

FAQ

What did Valion Bio (VBIO) announce about Entolimod and GI-ARS on June 25, 2026?

Valion Bio announced AFRRI/NIAID finalized a survival efficacy protocol to evaluate Entolimod for gastrointestinal acute radiation syndrome. According to Valion Bio, this PBI-BM2.5 murine model is designed for regulatory use under the FDA Animal Rule, supporting potential future licensure.

What is the AFRRI/NIAID PBI-BM2.5 protocol for Valion Bio’s Entolimod (VBIO)?

The AFRRI/NIAID PBI-BM2.5 protocol uses partial body irradiation with 2.5% bone marrow sparing at a lethal radiation dose. According to Valion Bio, this murine model isolates GI injury, creating a clearer efficacy signal for Entolimod’s mechanism targeting intestinal recovery and immune restoration.

How does the FDA Animal Rule relate to Valion Bio’s Entolimod (NASDAQ:VBIO)?

The FDA Animal Rule allows approval based on animal efficacy when human trials are unethical or infeasible. According to Valion Bio, the AFRRI/NIAID Entolimod protocol meets Animal Rule criteria, aiming to generate non-clinical data required for potential future licensure for GI-ARS.

Why is Entolimod being developed as a treatment for GI-ARS by Valion Bio (VBIO)?

Entolimod is being developed because no FDA-approved medical countermeasures currently exist for GI-ARS. According to Valion Bio, Entolimod’s TLR5 agonist mechanism promotes multi-tissue cytoprotection and targets gastrointestinal recovery, potentially addressing a lethal, currently untreated subsyndrome of acute radiation syndrome.

What market opportunity does Valion Bio (VBIO) see for Entolimod in acute radiation syndrome?

Valion Bio is targeting the acute radiation syndrome countermeasures market, estimated at $5.47B in 2025. According to Valion Bio, forecasts project expansion to $7.80B by 2032, with North America—driven by government stockpiling and biodefense spending—accounting for about 46% of market revenue.

How could the AFRRI/NIAID collaboration impact Valion Bio’s Entolimod (VBIO) development?

The AFRRI/NIAID collaboration provides a validated animal model and formal survival protocol for Entolimod. According to Valion Bio, this partnership and protocol may significantly derisk regulatory advancement by generating high-quality non-clinical efficacy data required for future FDA Animal Rule licensure discussions.