On May 7, 2025 Theriva Biologics (NYSE American: TOVX), ("Theriva" or the "Company"), a diversified clinical-stage company developing therapeutics designed to treat cancer and related diseases in areas of high unmet need, reported positive topline outcomes from the VIRAGE Phase 2b clinical trial evaluating the Company’s lead product candidate VCN-01 (zabilugene almadenorepvec) plus standard-of-care (SoC) chemotherapy gemcitabine/nab-paclitaxel as a first line therapy for patients with metastatic pancreatic ductal adenocarcinoma (PDAC) for whom gemcitabine/nab-paclitaxel is the recommended first-line treatment option (Press release, Theriva Biologics, MAY 7, 2025, View Source [SID1234652660]). VCN-01 is a systemically-administered, tumor selective, stroma-degrading oncolytic adenovirus that has been granted Orphan Drug Designation and Fast Track Designation by the U.S. Food and Drug Administration (FDA) for the treatment of pancreatic cancer.

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The analysis of the VIRAGE trial (see "About VIRAGE" below) includes data for first-line treatment of 96 newly-diagnosed metastatic PDAC patients:

In the primary endpoint analysis, the 48 patients treated with at least one dose of gemcitabine/nab-paclitaxel SoC had a median overall survival (OS) of 8.6 months, while the 48 patients treated with VCN-01 followed by at least one dose of gemcitabine/nab-paclitaxel SoC had a median OS of 10.8 months [Hazard Ratio (HR) = 0.57, 95% CI 0.34-0.96, p=0.0546].
The improvements in OS in the VCN-01+SoC treatment arm compared to the SoC control arm were reflected in increased progression free survival (PFS) [median PFS 7.0 vs 4.6 months; HR = 0.55, 95% CI 0.34-0.88, p= 0.0105].
The median duration of response (DoR) was 5.4 months (n=15) in the SoC control arm, while the median DoR in the VCN-01+SoC treatment arm was doubled to 11.2 months (n=19, HR = 0.22, 95% CI 0.08-0.62, p=0.0035).
The increase in OS was greater for patients who received 2 doses of VCN-01 and 4 or more cycles of gemcitabine/nab-paclitaxel SoC (n=34) compared with patients who received 4 or more cycles of gemcitabine/nab-paclitaxel SoC (n=29) [median OS 14.8 and 11.6 months respectively; HR=0.44, 95% CI: 0.21-0.92, p=0.046], suggesting that the second dose of VCN-01 (administered 3 months after the first dose) provides a meaningful additional benefit in this treatment subgroup.

"The exciting topline data from the VIRAGE Phase 2b trial demonstrate the potential opportunity for VCN-01 to benefit metastatic PDAC patients treated with gemcitabine/nab-paclitaxel SoC chemotherapy." said Steven A. Shallcross, Chief Executive Officer of Theriva Biologics. "The significantly reduced hazard ratios for survival parameters in the VCN-01 treatment group provide compelling evidence that VCN-01 in combination with gemcitabine/nab-paclitaxel may extend the lives of metastatic PDAC patients. These data, combined with recent advice from the U.S. FDA and the European Medical Agency, are expected to facilitate engagement with industry partners and enable the design of a Phase 3 confirmatory trial that, if successful, may deliver an important new therapeutic option for patients suffering this rapidly fatal disease."

As previously reported, the VCN-01 adverse event (AE) profile was consistent with that observed in prior clinical trials. The most common VCN-01 related AEs (pyrexia, flu-like illness, vomiting, nausea, and elevated transaminases) were transient and reversible. These AEs were observed to be less frequent and of reduced CTCAE grade after the second VCN-01 dose (administered on day ~92) compared to the first VCN-01 dose (administered on day 1). A review by an Independent Data Monitoring Committee noted that the overall type and number of AEs in the VCN-01 treatment group was as expected for the pancreatic cancer population, the duration of treatment, and the administration of an oncolytic virus.

Theriva will host a live virtual event to review and discuss the data from the VIRAGE trial of VCN-01 on Wednesday, May 7th 2025, 8:00 AM EDT. The virtual event will feature eminent pancreatic cancer clinician/researchers Dr. Manuel Hidalgo Medina MD PhD (Chief, Division of Hematology and Medical Oncology, Weill Cornell Medical College and Attending Physician, New York-Presbyterian Hospital) and Dr. Mike Pishvaian MD PhD (Director of Gastrointestinal, Developmental Therapeutics and Clinical Research Programs for the Johns Hopkins Kimmel Cancer Center and Associate Professor at the School of Medicine). To register for the event, click HERE.

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 is 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. The study was designed with 80% power to detect a HR of 0.65 for overall survival with a 1-sided alpha of 0.05 (2-sided alpha 0.1). Reported p-values are for 2-sided statistical analysis using the log rank test. 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).

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 over 140 patients to date in clinical trials of different cancers, including PDAC (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.