Theriva™ Biologics Reports Third Quarter 2025 Operational Highlights and Financial Results

- Expanded data for VCN-01 (zabilugene almadenorepvec) in metastatic pancreatic ductal adenocarcinoma (PDAC) from the VIRAGE Phase 2b trial presented at the European Society for Medical Oncology (ESMO) Annual Congress 2025 -

- Next generation oncolytic virus VCN-12 preclinical data presented at the 32ndAnnual Congress European Society of Gene & Cell Therapy (ESGCT) -

- Cash and cash equivalents of $7.5 millon as of September 30, 2025; recent capital raises increase cash to $15.5 million as of November 10, 2025 and extends cash runway into Q1 2027 -

ROCKVILLE, Md., Nov. 12, 2025 (GLOBE NEWSWIRE) -- Theriva™ Biologics (NYSE American: TOVX), a diversified clinical-stage company developing therapeutics designed to treat cancer and related diseases in areas of high unmet need, today reported financial results for the third quarter ended September 30, 2025, and provided a corporate update.

“Recent presentations of clinical data for VCN-01 and preclinical data for VCN-12 at medical congresses have highlighted the progress made across our oncology pipeline,” said Steven A. Shallcross, Chief Executive Officer of Theriva Biologics. “Having successully completed the VIRAGE Phase 2b clinical trial, we are now pursuing interactions with the European Medicines Agency and the US FDA to seek alignment on a protocol for a proposed Phase 3 study of VCN-01 plus gemcitabine/nab-paclitaxel standard-of-care chemotherapy as first-line treatment for metastatic PDAC. In addition, we have made significant progress on the design of a potential Phase 2/3 clinical trial in the rare pediatric disease retinoblastoma for potential discussion with regulators in the first half of 2026. With capital raised from our recent warrant inducement and sales made pursuant to our at-the-market (ATM) facility, we are well positioned to advance our regulatory and clinical strategies and explore potential partnerships for the innovative assets in our pipeline.”

Metastatic Pancreatic Ductal Adenocarcinoma (PDAC):

General and administrative expenses decreased to $1.9 million for the three months ended September 30, 2025, from $2.3 million for the three months ended September 30, 2024. This decrease of 18% is primarily comprised of the decrease in compensation costs offset by the increase in the fair value of the contingent consideration and increased investor relations expense. The charge related to stock-based compensation expense was the same for the three months ended September 30, 2025 and September 30, 2024. The Company expects general and administrative expenses to decrease due to the workforce reduction implemented on September 30, 2025.

Research and development expenses decreased to $2.6 million for the three months ended September 30, 2025, from approximately $2.7 million for the three months ended September 30, 2024. This decrease of 7% is primarily the result of lower clinical trial expenses related to the completion of the Company’s VIRAGE Phase 2b clinical trial of VCN-01 in PDAC, lower indirect cost related to decreased compensation and lower clinical trial expenses related to its Phase 1b/2a clinical trial of SYN-004 (ribaxamase) in allogeneic HCT recipients, offset by higher patent expenses related to SYN-020. The Company anticipates research and development expenses to decrease due to the completion of its VIRAGE Phase 2b clinical trial of VCN-01 as it focuses on regulatory interactions around potential pivotal clinical trials of VCN-01 in PDAC and retinoblastoma, continues exploratory VCN-01 manufacturing scale-up activities, and continues supporting the Company’s other preclinical and discovery initiatives. The charge related to stock-based compensation expense was $110,000 for the three months ended September 30, 2025, compared to $59,000 related to stock-based compensation expense for the three months ended September 30, 2024.

Other income was $79,000 for the three months ended September 30, 2025 compared to other income of $161,000 for the three months ended September 30, 2024. Other income for the three months ended September 30, 2025 is primarily comprised of interest income of $65,000 and an exchange gain of $14,000. Other income for the three months ended September 30, 2024 is primarily comprised of interest income of $158,000 and exchange gain of $3,000.

Cash and cash equivalents totaled $7.5 million as of September 30, 2025, compared to $11.6 million as of December 31, 2024. Following a capital raise subsequent to September 30, 2025, the Company’s cash and cash equivalents totaled $15.5 millon. The Company’s current cash of approximately $15.5 million at early November 2025 will allow it to fund operations into the first quarter of 2027, including overhead costs, close out of the VIRAGE Phase 2b clinical trial, exploratory VCN-01 manufacturing scale-up activities, regulatory interactions regarding proposed VCN-01 clinical trials in PDAC and retinoblastoma, and preclinical studies supporting VCN-01 and VCN-12, the first candidate from the Company’s VCN-X discovery program. Additional funding will be required to initiate new VCN-01 clinical trials.

VCN-01 (zabilugene almadenorepvec) is a systemically administered oncolytic adenovirus designed to selectively and aggressively replicate within tumor cells and degrade the tumor stroma that serves as a significant physical and immunosuppressive barrier to cancer treatment. This unique mode-of-action enables VCN-01 to exert multiple antitumor effects by (i) selectively infecting and lysing tumor cells; (ii) enhancing the access and perfusion of co-administered chemotherapy products; and (iii) increasing tumor immunogenicity and exposing the tumor to the patient’s immune system and co-administered immunotherapy products. Systemic administration enables VCN-01 to exert its actions on both the primary tumor and metastases. VCN-01 has been administered to 142 patients to date in clinical trials of different cancers, including pancreatic ductal adenocarcinoma (in combination with chemotherapy), head and neck squamous cell carcinoma (with an immune checkpoint inhibitor), ovarian cancer (with CAR-T cell therapy), colorectal cancer, and retinoblastoma (by intravitreal injection). More information on these clinical trials is available at Clinicaltrials.gov.

Cancer of the pancreas consists of two main histological types: cancer that arises from the ductal (exocrine) cells of the pancreas or, much less often, cancers may arise from the endocrine compartment of the pancreas. Pancreatic ductal adenocarcinoma (“PDAC”) accounts for more than 90% of all pancreatic tumors. It can be located either in the head of the pancreas or in the body/tail. Pancreatic cancer usually metastasizes to the liver and peritoneum. Other less common metastatic sites are the lungs, brain, kidney and bone. In its early stages, pancreatic cancer does not typically result in any characteristic symptoms, so in most cases it is diagnosed in its late stages (locally advanced non-metastatic or metastatic disease) when surgical resection and possibly curative treatment is not possible. It is generally assumed that only 10% of cases are resectable at presentation, whereas 30-40% of patients are diagnosed at local advanced/unresectable stage and 50-60% present with distant metastases.

VIRAGE was a two-arm, Phase 2b open-label, randomized, controlled, multicenter clinical trial in patients with histologically confirmed, newly-diagnosed metastatic PDAC. Patients were enrolled at 5 sites in the U.S. and 9 sites in Spain. In both the control and VCN-01 (zabilugene almadenorepvec) treatment arms, patients received gemcitabine/nab-paclitaxel standard-of-care chemotherapy in repeated 28-day cycles until disease progression. In the VCN-01 treatment arm only, patients were also administered intravenous VCN-01 seven-days prior to starting the first and fourth cycles of gemcitabine/nab-paclitaxel treatment (study days 1 and ~92, respectively). Primary endpoints for the trial include overall survival and VCN-01 safety/tolerability. Additional endpoints include progression free survival, duration of response, and measures of VCN-01 biodistribution, replication, and immune response. More information about the trial is available on Clinicaltrials.gov (NCT05673811), through the Spanish Clinical Trials Registry and European Union Drug Regulating Authorities Clinical Trials Database (EudraCT Number: 2022-000897-24).

Theriva™ Biologics (NYSE American: TOVX), is a diversified clinical-stage company developing therapeutics designed to treat cancer and related diseases in areas of high unmet need. The Company’s subsidiary Theriva Biologics, S.L. , has been developing a new oncolytic adenovirus platform designed for intravenous (IV), intravitreal and antitumoral delivery to trigger tumor cell death, improve access of co-administered cancer therapies to the tumor, and promote a robust and sustained anti-tumor response by the patient’s immune system. The Company’s lead clinical-stage candidates are: (1) VCN-01 (zabilugene almadenorepvec), an oncolytic adenovirus designed to replicate selectively and aggressively within tumor cells, and to degrade the tumor stroma barrier that serves as a significant physical and immunosuppressive barrier to cancer treatment; (2) SYN-004 (ribaxamase) which is designed to degrade certain commonly used IV beta-lactam antibiotics within the gastrointestinal (GI) tract to prevent microbiome damage, thereby limiting overgrowth of pathogenic organisms such as VRE (vancomycin resistant Enterococci) and reducing the incidence and severity of acute graft-versus-host-disease (aGVHD) in allogeneic hematopoietic cell transplant (HCT) recipients; and (3) SYN-020, a recombinant oral formulation of the enzyme intestinal alkaline phosphatase (IAP) produced under cGMP conditions and intended to treat both local GI and systemic diseases. For more information, please visit Theriva Biologics’ website atwww.therivabio.com.

This release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. In some cases forward-looking statements can be identified by terminology such as “may,” “should,” “potential,” “continue,” “expects,” “anticipates,” “intends,” “plans,” “believes,” “estimates,” and similar expressions, and include statements regarding the advancement of its oncology pipeline, pursuing interactions with the European Medicines Agency and the US FDA to seek agreement on a protocol for a proposed Phase 3 study of VCN-01 plus gemcitabine/nab-paclitaxel standard-of-care chemotherapy as first-line treatment for metastatic PDAC, progressing on the design of a potential Phase 2/3 clinical trial in the rare pediatric disease retinoblastoma for discussion with regulators in the first half of 2026, being well positioned to advance the Company’s regulatory and clinical strategies and explore potential partnerships for the innovative assets in its pipeline, ongoing additional preclinical studies to confirm the findings for VCN-12 presented at the ESGCT 32nd Annual Congress, general and administrative expenses decreasing due to the workforce reduction implemented on September 30, 2025, research and development expenses decreasing due to the completion of the VIRAGE Phase 2b clinical trial of VCN-01, focusing on regulatory interactions around potential pivotal clinical trials of VCN-01 in PDAC and retinoblastoma, continuing exploratory VCN-01 manufacturing scale-up activities, and continuing to support the Company’s other preclinical and discovery initiatives, current cash funding operations into the first quarter of 2027, including overhead costs, close out of the VIRAGE Phase 2b clinical trial, exploratory VCN-01 manufacturing scale-up activities, regulatory interactions regarding proposed VCN-01 clinical trials in PDAC and retinoblastoma, and preclinical studies supporting VCN-01 and VCN-12, and additional funding being required to initiate new VCN-01 clinical trials. These forward-looking statements are based on management’s expectations and assumptions as of the date of this press release and are subject to a number of risks and uncertainties, many of which are difficult to predict that could cause actual results to differ materially from current expectations and assumptions from those set forth or implied by any forward-looking statements. Important factors that could cause actual results to differ materially from current expectations include, among others, the Company’s product candidates, including VCN-01 and VCN-12, demonstrating safety and effectiveness in clinical indications, as well as results that are consistent with prior results; the ability to confirm VCN-12 preclinical data in the clinical setting; the Company’s ability to reach clinical milestones when anticipated including enrolling the expected number of patients in each trial; the Company’s ability to complete clinical trials on time and achieve the desired results and benefits; the Company’s ability to obtain regulatory approval for commercialization of product candidates or to comply with ongoing regulatory requirements; regulatory limitations relating to the Company’s ability to promote or commercialize its product candidates for the specific indications; acceptance of product candidates in the marketplace and the successful development, marketing or sale of the Company’s products; developments by competitors that render such products obsolete or non-competitive; the Company’s ability to maintain license agreements; the continued maintenance and growth of the Company’s patent estate; the Company’s ability to continue to remain well financed; and other factors described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024 and its other filings with the SEC, including subsequent periodic reports on Forms 10-Q and current reports on Form 8-K. The information in this release is provided only as of the date of this release, and Theriva undertakes no obligation to update any forward-looking statements contained in this release on account of new information, future events, or otherwise, except as required by law.