On November 12, 2025 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, reported financial results for the third quarter ended September 30, 2025, and provided a corporate update.

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"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."

Recent Highlights and Anticipated Milestones

VCN-01

Metastatic Pancreatic Ductal Adenocarcinoma (PDAC):

Expanded data from the VIRAGE randomized, controlled clinical trial investigating up to two doses of VCN-01 (zabilugene almadenorepvec) in combination with gemcitabine/nab-paclitaxel standard-of-care (SoC) chemotherapy in 112 metastatic PDAC patients were presented at ESMO (Free ESMO Whitepaper) 2025:
The ESMO (Free ESMO Whitepaper) presentation included data for patients randomized into the modified intent to treat (mITT) population, who received at least 1 dose of SoC chemotherapy (Arm I) or at least 1 dose of VCN-01 (Arm II) regardless of whether they received SoC chemotherapy. These were compared to data for the full analysis set (FAS), where patients received at least 1 dose of gemcitabine/nab-paclitaxel SoC chemotherapy (Arm I) or VCN-01 followed by at least 1 dose of SoC chemotherapy (Arm II).
As previously reported, the two doses of VCN-01 were well tolerated and the study met its primary endpoints, such that metastatic PDAC patients receiving VCN-01 with SoC chemotherapy had improved overall survival (OS), progression free survival (PFS) and Duration of Response (DoR) compared to SoC chemotherapy alone. Improvements in these parameters were observed in both the mITT and FAS populations.
Patients who received 2 doses of VCN-01 and started cycle 4 of SoC chemotherapy (Arm II) showed greater improvement in OS and PFS compared to patients who started cycle 4 of SoC chemotherapy alone (Arm I), indicating a potential benefit of additional VCN-01 doses.
Expanded data presented at ESMO (Free ESMO Whitepaper) 2025 showed that peaks of VCN-01 viral genomes (vg) in blood were similar after both VCN-01 doses and circulating vgs were measurable for at least 3 months after each dose despite the presence of neutralizing antibodies. These data highlight the persistent bioactivity of intravenously administered VCN-01 upon repeated dosing.
Following the successful VIRAGE Phase 2b trial, a study protocol for a potential Phase 3 clinical trial investigating VCN-01 plus gemcitabine/nab-paclitaxel SoC chemotherapy as first-line treatment for metastatic PDAC is planned to be discussed with regulators in Europe and the United States.
VCN-12

VCN-12 is a next generation oncolytic adenovirus developed as part of Theriva’s VCN-X discovery program
VCN-12 uses the same virus capsid as the Company’s lead clinical candidate VCN-01 (zabilugene almadenorepvec), but includes modifications intended to (i) increase stroma degradation by replacing human hyaluronidase PH20 with the more active bee hyaluronidase; and (ii) increase tumor cell lysis by expressing the pore forming protein parasporin-2 to enable both cytotoxic and immunogenic cell death.
Preclinical data for VCN-12 was presented at the ESGCT 32nd Annual Congress:
Data presented at ESGCT showed that VCN-12 provided increased cell killing compared to VCN-01 in a variety of cancer cell models in vitro and displayed higher levels of hyaluronidase activity. In animal studies, intravenous VCN-12 had a similar toxicity profile to VCN-01 in immunodeficient mice bearing human tumor xenografts. Intratumoral VCN-12 significantly reduced tumor growth compared to VCN-01 in immunocompetent hamsters bearing HP-1 pancreatic tumors and appeared to stimulate a persistent anti-tumor immune response that prevented tumor establishment in some VCN-12 treated animals. Additional preclinical studies to confirm these findings are ongoing.
Third Quarter Ended September 30, 2025 Financial Results

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.

About VCN-01

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.

About Pancreatic Ductal Adenocarcinoma

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.

About VIRAGE

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).

(Press release, Theriva Biologics, NOV 12, 2025, View Source [SID1234659845])