Suitability of Vaccine Platform for Bundibugyo Virus, Cause of the Ebola Outbreak in Congo

Rhea-AI Summary

Soligenix (Nasdaq:SNGX) highlighted the suitability of its ThermoVax thermostable vaccine platform for rapid development of a Bundibugyo virus vaccine amid the Congo outbreak. Existing bivalent and trivalent filovirus vaccines using this platform have shown thermostability, strong immune responses in animals, and up to 100% protection in non-human primates.

The platform supports ambient-temperature shipping, single-vial subunit formulations, and potential use as stand-alone or booster vaccines. According to Soligenix, development of a thermostable Bundibugyo virus vaccine, alone or in combination, could proceed rapidly given adequate funding.

Positive

• Filovirus vaccines on platform showed up to 100% protection in non-human primates
• ThermoVax-based vaccines demonstrate thermostability and extended stability at ambient temperatures
• Platform already used for Ebola, Sudan, Marburg and COVID vaccine candidates
• Bundibugyo virus antigen is compatible with existing platform, enabling rapid vaccine design
• Single-vial subunit format may simplify storage, distribution and booster use

Negative

• Advancement of a Bundibugyo virus vaccine is contingent on securing adequate funding
• New Bundibugyo outbreak requires fresh vaccine formulation; no approved Bundibugyo product yet disclosed

News Market Reaction – SNGX

+31.50% 17.7x vol

109 alerts

+31.50% Session close to close

+204.8% Peak Tracked

-10.5% Trough Tracked

$8.92M Market Cap

17.7x Rel. Volume

In the May 26 session, SNGX gained 31.50%, reflecting a significant positive market reaction. Argus tracked a peak move of +204.8% during that session. Argus tracked a trough of -10.5% from its starting point during tracking. Our momentum scanner triggered 109 alerts that day, indicating very high trading interest and price volatility. Trading volume was exceptionally heavy at 17.7x the daily average, suggesting very strong buying interest.

Data tracked by StockTitan Argus on the day of publication.

Market Context

The stock surged +31.5% in the session following this news. A strong positive reaction aligns with p...

Analysis

The stock surged +31.5% in the session following this news. A strong positive reaction aligns with prior sensitivity to major pipeline developments. The company previously saw a -70.25% move when FLASH2 was halted, and modest gains of 6.31% on constructive year-end results. Investors watching the ThermoVax® platform may weigh this Bundibugyo-focused update against going-concern disclosures and warrant overhang highlighted in recent 424B3 and 10-Q filings.

Key Figures

Protection rate: 100%

1 metrics

Protection rate 100% Non-human primates in filovirus vaccine studies using Soligenix platform

Historical Context

5 past events · Latest: May 08 (Negative)

Pattern 5 events

Date	Event	Sentiment	24h Move	Catalyst
May 08	Earnings and pipeline	Negative	-4.9%	Q1 2026 loss, limited cash runway, FLASH2 halt and strategic review.
Apr 28	Phase 3 futility halt	Negative	-70.3%	Data Monitoring Committee recommended halting FLASH2 for futility.
Apr 02	Positive HyBryte study	Positive	-0.9%	HyBryte showed better responses and safety vs Valchlor in CTCL study.
Mar 31	Year-end 2025 results	Positive	+6.3%	Reported cash balance and highlighted upcoming Phase 3 HyBryte milestones.
Mar 26	EU orphan designation	Positive	+0.8%	EC granted orphan drug designation to SGX945 for Behçet's Disease.

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

Pattern Detected

News flow has recently been dominated by the FLASH2 Phase 3 setback and going‑concern disclosures. Negative trial/earnings updates often coincided with notable selloffs, while even positive clinical publications have not consistently produced upside.

Recent Company History

Over the last few months, Soligenix has shifted from advancing HyBryte toward Phase 3 milestones to managing a major setback. On Apr 28, 2026, the FLASH2 trial was halted for futility, driving a -70.25% move. Subsequent filings and Q1 2026 results on May 8, 2026 highlighted a $2.8M quarterly net loss, cash of about $6.0M, and going-concern risks. Earlier, positive HyBryte comparative data (Apr 2, 2026) and EU orphan designation for SGX945 (Mar 26, 2026) showed scientific and regulatory progress but produced only modest stock reactions.

Key Terms

thermostability, immunogenicity, orthoebolavirus, adjuvant, +4 more

8 terms

thermostability medical

"demonstrating thermostability, immunogenicity and durable efficacy."

Thermostability describes how well a biological product, such as a protein, vaccine, or diagnostic reagent, keeps its shape and function when exposed to heat or changes in temperature. For investors it matters because higher thermostability can lower storage and shipping costs, reduce waste and regulatory hurdles, and expand market reach—similar to how a packed lunch that stays fresh longer is easier and cheaper to transport and sell.

immunogenicity medical

"demonstrating thermostability, immunogenicity and durable efficacy."

Immunogenicity is the ability of a substance, such as a vaccine or medication, to provoke an immune response in the body. It matters to investors because high immunogenicity can affect the effectiveness and safety of a product, potentially leading to increased costs or regulatory challenges. Understanding immunogenicity helps assess the long-term viability and market potential of pharmaceutical and biotech investments.

orthoebolavirus medical

"recent Congo outbreak of Bundibugyo virus, an Orthoebolavirus, will require"

A genus of related viruses that can cause severe hemorrhagic fever in humans and animals, most commonly known for strains that have triggered outbreaks. Investors pay attention because outbreaks can prompt emergency public-health measures, shift demand for medical supplies and treatments, disrupt travel and supply chains, and move shares of healthcare, biotech, and travel-related companies—similar to how a single wildfire can change business activity across a region.

adjuvant medical

"Marburg virus and the CoVaccine HT™ adjuvant, demonstrating thermostability"

An adjuvant is an ingredient added to a vaccine or other therapy to strengthen or shape the body’s response to the main active component, like a helper that makes the primary ingredient work better or longer. For investors, adjuvants matter because they can change how well a product performs, alter dosing and safety profiles, affect regulatory review, and therefore influence clinical success, market size and competitive advantage.

non-human primates medical

"broad and robust immune responses in mice and up to 100% protection in non-human primates"

Non-human primates are members of the primate family other than people — such as monkeys and apes — that are used in biomedical research because their biology is closer to humans than rodents. For investors, results from studies in these animals can strongly influence a drug or vaccine’s safety profile, development timeline, regulatory chances and costs, acting like a high-fidelity dress rehearsal before human clinical trials.

subunit vaccine medical

"rapid development of a protein-based thermostable subunit vaccine."

A subunit vaccine delivers only specific pieces of a virus or bacterium—usually proteins—rather than the whole germ, training the immune system to recognize and respond without exposing the body to a live or weakened pathogen. For investors, these vaccines often mean lower safety risk, simpler manufacturing and storage, and clearer regulatory paths, so progress, production capacity, and partnerships can materially affect a company’s commercial prospects and valuation.

protein subunit vaccines medical

"makes protein subunit vaccines, the gold standard for safe vaccines, competitive"

Protein subunit vaccines use harmless pieces of a pathogen—usually specific proteins—to teach the immune system to recognize and fight the real thing without exposing the body to live virus. For investors, they matter because their generally strong safety profiles, established manufacturing methods, and predictable regulatory pathways can reduce development risk and open steady market demand for boosters or seasonal updates, while manufacturing scale and supply chains influence cost and profitability.

strategic national stockpiles regulatory

"context of strategic national stockpiles and preparations for potential larger outbreaks"

Strategic national stockpiles are government-maintained reserves of critical medical supplies, vaccines, and equipment held for use during public health emergencies, similar to a household keeping an emergency kit for disasters. Investors watch these stockpiles because government purchases, release schedules, or replenishment contracts can create sudden demand for manufacturers and suppliers, affecting revenue forecasts, supply chains, and the valuation of companies that produce those goods.

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

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Thermostability, immunogenicity and efficacy data against related viruses
may provide rapid starting point for vaccine development

PRINCETON, N.J., May 26, 2026 /PRNewswire/ -- Soligenix, Inc. (Nasdaq: SNGX) (Soligenix or the Company), a late-stage biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need, noted today that the recent Congo outbreak of Bundibugyo virus, an Orthoebolavirus, will require new vaccine formulation efforts. Soligenix, in collaboration with Axel Lehrer, PhD, Professor at the Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaiʻi at Mānoa, has previously developed bivalent and trivalent vaccines, constructed from antigens against Ebola virus, Sudan virus and Marburg virus and the CoVaccine HT™ adjuvant, demonstrating thermostability, immunogenicity and durable efficacy. Previous work in Dr. Lehrer's laboratory has demonstrated platform compatibility of the key Bundibugyo virus antigen enabling rapid development of a protein-based thermostable subunit vaccine.

"Our filovirus vaccines have demonstrated broad and robust immune responses in mice and up to 100% protection in non-human primates," stated Dr. Lehrer. "Further, we have developed thermostable vaccine formulations in collaboration with Soligenix, demonstrating extended stability that is particularly relevant for the use of these vaccines in virus-endemic countries in Africa, as well as in the context of strategic national stockpiles and preparations for potential larger outbreaks and pandemics. A single-vial subunit vaccine that can be shipped at ambient temperatures and then needs to only be reconstituted with sterile water immediately prior to use has the potential to improve vaccination efforts globally by simplifying storage and distribution logistics not only as a stand-alone vaccine, but also as a practical add-on booster in persons previously vaccinated with other vaccines. Given adequate funding, we are confident we could rapidly advance development of a thermostable Bundibugyo virus vaccine individually or in combination vaccines developed previously."

"Our ThermoVax^® platform has successfully thermostabilized vaccines for ricin toxin, for filoviruses such as Ebola, Sudan and Marburg, and for COVID, and as such is a well-established thermostabilization strategy that enhances the long-standing protein subunit vaccination technology. We believe this enhancement makes protein subunit vaccines, the gold standard for safe vaccines, competitive with other vaccine technologies, which have much more stringent cold-storage requirements," stated Christopher J. Schaber, PhD, President and Chief Executive Officer of Soligenix. "The ability of these vaccines to induce rapid broad immune coverage, even when administered after other primary vaccination series, is another marked advantage. Moreover, the use of subunit vaccines that has been built on years of proven vaccine technology may also provide a very safe option for people of all ages."

About Filovirus Vaccines

These proprietary filovirus vaccines are subunit protein vaccines of recombinantly expressed Orthoebolavirus sudanense glycoprotein, Orthoebolavirus zairense glycoprotein and Orthomarburgvirus marburgense glycoprotein developed in partnership with Dr. Axel Lehrer at the University of Hawaiʽi at Mānoa. Dr. Lehrer's team has also previously used the same expression platform to produce glycoprotein of Orthoebolavirus bundibugyoense, which has already found application in collaborative seroepidemiology studies conducted in the Democratic Republic of the Congo (DRC). All filovirus vaccines include a protein found on the surface of each virus, to engender an appropriate immune response without posing a risk of infection, as well as a novel adjuvant which stimulates both humoral and cell mediated immune responses, in combination with Generally Regarded As Safe (GRAS) excipients that enable lyophilization (i.e., freeze-drying) of the vaccines. The resulting products are manufactured as a heat stable powder in a vial which is reconstituted with widely available water for injection immediately prior to use. Alone or in combination, these heat stable protein subunit vaccines, have protected up to100% of non-human primates exposed to a lethal injection of the corresponding virus. Stability studies have demonstrated that these vaccines are heat stable for at least 2 years at temperatures of at least 40 degrees Celsius (104 degrees Fahrenheit).

Manufacture of the recombinant proteins utilizes a robust protein manufacturing process, developed and tested in other subunit vaccines advanced through clinical testing. Similarly, the selected adjuvant, while novel, has also been independently tested in Phase 1 and Phase 2 clinical studies.

Soligenix has been granted Orphan Drug Designation by the United States Food and Drug Administration (FDA) for the prevention and post-exposure prophylaxis against Sudan orthoebolavirus and Marburg orthomarburgvirus infection. In addition to providing a seven-year term of market exclusivity upon final FDA approval, orphan drug designations also position Soligenix to be able to leverage a wide range of financial and regulatory benefits, including government grants for conducting clinical trials, waiver of expensive FDA user fees for the potential submission of a Biologics License Application (BLA), and certain tax credits.

About Filovirus Infection

Ebola Virus Disease is caused by one of six species of Ebolavirus, four of which are known to cause disease in humans, including its best-known member, Orthoebolavirus zairense (Ebola virus), with Orthoebolavirus sudanense being the second-most common cause of human infection in this family. Other known human pathogenic viruses include Orthoebolavirus bundibugyoense and Orthoebolavirus taiense. All species of orthoebolavirus belong to the Filoviridae family, a family that further contains the equally human pathogenic Marburg virus. Filoviruses are believed to be harbored in various animal species in Africa, particularly bats, although the specific reservoir host for many of these viruses is still unknown. There have been several known Ebola, Sudan, Bundibugyo and Marburg Virus Disease outbreaks since 1967. The most recent SUDV outbreak occurred in January – April, 2025 in Uganda according to the Centers for Disease Control and Prevention (CDC). The most recent MARV outbreaks occurred in January – March 2025 in Tanzania, according to the CDC. Most recently, the Bundibugyo virus has been identified as responsible for the ongoing outbreak in the Democratic Republic of Congo and Uganda, with 80 deaths, and 246 suspected cases as of May 15, 2026. This outbreak was declared a Public Health Emergency of International Concern by the World Health Organization on May 16, 2026 and is ongoing.

Transmission of filoviruses requires direct contact with bodily fluids from an infected person or contact with infected animals. The mortality rates following filovirus infections are extremely high, and, in the absence of wide availability of effective therapeutics, are affected by the quality of supportive care available with a focus on early initiation of treatment. Resolution of the disease largely depends on the patient's own immune system. There currently are limited treatment options for Ebola Virus Disease and no available treatments for Sudan, Bundibugyo or Marburg Virus Disease, although steady progress has also been made in development of immunotherapeutics for filoviruses beyond Orthoebolavirus zairense. There are approved vaccines for Ebola virus, requiring stringent ultra-low cold-chain storage, but no efficacious and approved vaccines are available for Sudan, Bundibugyo, or Marburg virus.

About John A. Burns School of Medicine, University of Hawaiʽi at Mānoa

Established in 1965, the John A. Burns School of Medicine (JABSOM) is one of the degree-granting schools of the University of Hawaiʻi at Mānoa. Named in honor of the visionary former governor, JABSOM trains the next generation of outstanding physicians, scientists, medical technologists, and speech pathologists to improve the health and wellness of our diverse communities throughout Hawaiʻi and the Pacific. Our impactful research focuses on understanding and addressing health disparities, particularly in Native Hawaiian, Pacific Islander, and Filipinos. JABSOM is home to the first clinical department in an accredited medical school in the nation that is focused on health disparities of an indigenous population, Native Hawaiians.

About Soligenix, Inc.

Soligenix is a biopharmaceutical company focused on developing and commercializing products to treat rare diseases where there is an unmet medical need. Our Specialized BioTherapeutics business segment is developing synthetic hypericin for the treatment of psoriasis (SGX302), and our first-in-class Innate Defense Regulator (IDR) technology, dusquetide, for the treatment of inflammatory diseases, including aphthous ulcers in Behçet's Disease (BD) (SGX945) and oral mucositis in head and neck cancer (SGX942). We were developing HyBryte™ (SGX301 or synthetic hypericin sodium), a photodynamic therapy utilizing visible light, for the treatment of cutaneous T-cell lymphoma (CTCL) in a Phase 3 study called "FLASH2" (Fluorescent Light Activated Synthetic Hypericin 2). The Data Monitoring Committee completed its interim efficacy analysis of the FLASH2 trial during April 2026, and under the terms of the interim analysis, the study was recommended to halt for futility. We are in the process of analyzing the data to better determine why the study did not meet expectations.

Our Public Health Solutions business segment includes development programs for RiVax^®, our ricin toxin vaccine candidate, as well as our vaccine programs targeting filoviruses (such as Marburg and Ebola) and CiVax™, our vaccine candidate for the prevention of COVID-19 (caused by SARS-CoV-2). The development of our vaccine programs incorporates the use of our proprietary heat stabilization platform technology, known as ThermoVax^®. To date, this business segment has been supported with government grant and contract funding from the National Institute of Allergy and Infectious Diseases (NIAID), the Defense Threat Reduction Agency (DTRA) and the Biomedical Advanced Research and Development Authority (BARDA).

For further information regarding Soligenix, Inc., please visit the Company's website at https://www.soligenix.com and follow us on LinkedIn and X at @Soligenix_Inc.

This press release may contain forward-looking statements that reflect Soligenix's current expectations about its future results, performance, prospects and opportunities, including but not limited to, potential market sizes, patient populations and clinical trial enrollment. Statements that are not historical facts, such as "anticipates," "estimates," "believes," "hopes," "intends," "plans," "expects," "goal," "may," "suggest," "will," "potential," or similar expressions, are forward-looking statements. These statements are subject to a number of risks, uncertainties and other factors that could cause actual events or results in future periods to differ materially from what is expressed in, or implied by, these statements, and include the expected timing and results of clinical trials and the expected timing of regulatory submissions and approvals. In light of the discontinuation of the FLASH2 study, the Company's ability to continue as a going concern will be dependent upon its ability to develop and commercialize its remaining pipeline assets, including dusquetide for the treatment of Behçet's Disease, to identify and acquire or in-license additional product candidates or technologies, and to raise sufficient capital to fund such development and any such acquisitions. There can be no assurance that the Company will be able to obtain financing on acceptable terms, if at all, that suitable acquisition or in-licensing opportunities will be available, or that any of its remaining or future development programs will be successful. If the Company is unable to raise sufficient capital or otherwise advance its remaining assets, it may be required to significantly curtail or cease its operations, sell or otherwise dispose of its assets, or pursue dissolution and liquidation. Soligenix cannot assure you that it will be able to successfully develop, achieve regulatory approval for or commercialize products based on its technologies, particularly in light of the significant uncertainty inherent in developing therapeutics and vaccines against bioterror threats, conducting preclinical and clinical trials of therapeutics and vaccines, obtaining regulatory approvals and manufacturing therapeutics and vaccines, that product development and commercialization efforts will not be reduced or discontinued due to difficulties or delays in clinical trials or due to lack of progress or positive results from research and development efforts, that it will be able to successfully obtain any further funding to support product development and commercialization efforts, including grants and awards, maintain its existing grants which are subject to performance requirements, enter into any biodefense procurement contracts with the U.S. Government or other countries, that it will be able to compete with larger and better financed competitors in the biotechnology industry, that changes in health care practice, third party reimbursement limitations and Federal and/or state health care reform initiatives will not negatively affect its business, or that the U.S. Congress may not pass any legislation that would provide additional funding for the Project BioShield program. In addition, there can be no assurance as to the timing or success of any of its clinical/preclinical trials. Despite the statistically significant result achieved in the first HyBryte™ (SGX301) Phase 3 clinical trial for the treatment of cutaneous T-cell lymphoma or any other studies (including the open-label, investigator-initiated study) and the overall blinded study response rate observed in the second HyBryte™ (SGX301) Phase 3 clinical trial, notwithstanding any prior observations regarding such blinded response rate, the second HyBryte™ (SGX301) Phase 3 clinical trial did not demonstrate sufficient efficacy at the interim analysis to support continuation of the study, and no assurance can be given that any further development of HyBryte™ (SGX301) will be pursued or that a marketing authorization from the FDA or EMA will be sought or granted. Notwithstanding the result of HyBryte™ (SGX301) in the first Phase 3 clinical trial (or any other studies) for the treatment of cutaneous T-cell lymphoma and the Phase 2a clinical trial of SGX302 for the treatment of psoriasis, there can be no assurance as to the timing or success of the clinical trials of SGX302 for the treatment of psoriasis. Additionally, despite the biologic activity observed in aphthous ulcers induced by chemotherapy and radiation, there can be no assurance as to the timing or success of the clinical trials of SGX945 for the treatment of Behçet's Disease. Further, there can be no assurance that RiVax^® will qualify for a biodefense Priority Review Voucher (PRV) or that the prior sales of PRVs will be indicative of any potential sales price for a PRV for RiVax^®. Also, no assurance can be provided that the Company will receive or continue to receive non-dilutive government funding from grants and contracts that have been or may be awarded or for which the Company will apply in the future. These and other risk factors are described from time to time in filings with the Securities and Exchange Commission (the "SEC"), including, but not limited to, Soligenix's reports on Forms 10-Q and 10-K. Unless required by law, Soligenix assumes no obligation to update or revise any forward-looking statements as a result of new information or future events.

View original content to download multimedia:https://www.prnewswire.com/news-releases/suitability-of-vaccine-platform-for-bundibugyo-virus-cause-of-the-ebola-outbreak-in-congo-302780813.html

SOURCE SOLIGENIX, INC.

FAQ

What did Soligenix (NASDAQ:SNGX) announce about its Bundibugyo virus vaccine plans on May 26, 2026?

Soligenix announced its ThermoVax platform is compatible with Bundibugyo virus antigens, supporting rapid vaccine development. According to Soligenix, prior filovirus vaccines using this platform showed thermostability, strong immune responses, and up to 100% protection in non-human primates, subject to further development and funding.

How suitable is Soligenix's ThermoVax platform for a Bundibugyo virus vaccine (SNGX)?

ThermoVax is described as a well-established thermostabilization strategy for protein subunit vaccines. According to Soligenix, Bundibugyo virus antigens are compatible with this platform, enabling development of thermostable, protein-based subunit vaccines that could be shipped at ambient temperature and reconstituted before use.

What preclinical results support Soligenix's filovirus vaccine platform for investors in SNGX?

Filovirus vaccines developed with ThermoVax and CoVaccine HT reportedly induced broad immune responses in mice and up to 100% protection in non-human primates. According to Soligenix, these data, along with demonstrated thermostability and durability, provide a foundation for extending the platform to Bundibugyo virus.

How could Soligenix's thermostable vaccines impact outbreak response and stockpiling for SNGX shareholders?

Thermostable, ambient-shippable vaccines could simplify logistics in virus-endemic regions and strategic stockpiles. According to Soligenix, single-vial subunit vaccines reconstituted with sterile water may improve deployment during outbreaks and serve as practical booster doses after other primary vaccination series.

What role does funding play in Soligenix's Bundibugyo virus vaccine development (SNGX)?

Funding is presented as a key requirement for advancing Bundibugyo vaccine candidates. According to Soligenix, adequate financial support could allow rapid development of a thermostable Bundibugyo virus vaccine, either as a stand-alone product or combined with existing filovirus vaccine formulations.

Why does Soligenix emphasize protein subunit vaccines for Bundibugyo virus (SNGX)?

Soligenix describes protein subunit vaccines as a long-standing, safe technology and calls them a “gold standard” for safety. According to Soligenix, ThermoVax-enhanced subunit vaccines may compete with other technologies while reducing cold-chain demands and offering a potentially safe option across age groups.