Exhibit 99.1

Theriva™ Biologics Announces Primary Endpoints for Efficacy and Safety Achieved in VIRAGE Phase 2b Clinical Trial of VCN-01 with Gemcitabine/nab-Paclitaxel in Newly-Diagnosed Metastatic Pancreatic Cancer Patients

- Patients treated with VCN-01 (zabilugene almadenorepvec) plus gemcitabine/nab-paclitaxel standard-of-care (SoC) chemotherapy had increased overall survival, progression free survival, and duration of response compared to patients treated with gemcitabine/nab-paclitaxel SoC -

- VCN-01 was well-tolerated, with transient and reversible adverse events (AEs), meeting primary safety endpoint -

- Greater differences between the treatment arms were observed in patients receiving 2 doses of VCN-01 -

- Data to be reviewed during a Key Opinion Leader webinar Featuring Dr. Manuel Hidalgo Medina and Dr. Mike Pishvaian on Wednesday May 7^th, 2025 at 0800 US EDT -

Rockville, MD, May 07, 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, today announced 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. 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.

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

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 7^th 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.

About Theriva™ Biologics, Inc.

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 product candidate is 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. Additional clinical stage assets include (1) 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 (2) 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 at www.therivabio.com.

Forward-Looking Statement

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 exciting topline data from the VIRAGE Phase 2b trial demonstrating the potential opportunity for VCN-01 to benefit metastatic PDAC patients treated with gemcitabine/nab-paclitaxel SoC chemotherapy; the significantly reduced hazard ratios for survival parameters in the VCN-01 treatment group providing compelling evidence that VCN-01 in combination with gemcitabine/nab-paclitaxel may extend the lives of metastatic PDAC patients; and the data, combined with recent advice from the U.S. FDA and the European Medical Agency, being 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. 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 ability of VCN-01 to benefit metastatic PDAC patients treated with gemcitabine/nab-paclitaxel; the ability of VCN-01 in combination with gemcitabine/nab-paclitaxel to extend the lives of metastatic PDAC patients; the data facilitating engagement with industry partners; the ability to confirm the potential therapeutic benefits of VCN-01 in a Phase 3 clinical trial and delivering an important new therapeutic option for metastatic PDAC patients; the Company’s ability to reach clinical milestones when anticipated including enrolling the expected number of patients in each trial; the Company’s product candidates, including VCN-01, demonstrating safety and effectiveness, as well as results that are consistent with prior results; the ability to complete clinical trials on time and achieve the desired results and benefits, continuing clinical trial enrollment as expected; the 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 their 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 and VCN’s patent estate, the 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 Biologics 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.

For further information, please contact:

Investor Relations:
Kevin Gardner
LifeSci Advisors, LLC
kgardner@lifesciadvisors.com
617-283-2856

Source: Theriva Biologics, Inc.

Exhibit 99.2

VIRAGE Phase 2b Clinical Trial of VCN - 01 in Pancreatic Cancer 07 May 2025

2 FORWARD LOOKING STATEMENTS This presentation 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 oncolytic viruses (OVs) being promising cancer therapeutics; the multiple potential value opportunities for VCN - 01; the regulatory status expected to facilitate VCN - 01 development; potential access to a priority review voucher; the therapeutic potential of VCN - 01 and other Theriva OVs; the ability of VCN - 01 and other Theriva OVs to overcome key OV challenges ; the potential of VCN - 01 to enable immuno - oncology therapies in refractory tumors; the clinical advancement of VCN - 01 and other Theriva OVs in div erse cancer indications (including pancreatic ductal adenocarcinoma, head and neck cancer, ovarian cancer, colorectal cancer, and retinob las toma) and the projected milestones . Important factors that could cause actual results to differ materially from current expectations include, among others, the Co mpany’s ability to enroll patients as planned and reach clinical trial milestones when anticipated ; the Company’s ability to complete clinical trials on time and achieve the desired results and benefits ; the Company’s product candidates demonstrating safety and effectiveness, including positive clinical data that demonstrates VCN - 01 may lead to improved clinical outcomes for patients; the Company’s ability to obtain regulatory approval for commercializ ation of product candidates or to comply with ongoing regulatory requirements; regulatory limitations relating to the Company’s ability to pro mot e or commercialize their product candidates for the specific indications; acceptance of product candidates in the marketplace and the successful devel opm ent, 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 ability to continue to remain well finan ced ; 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, i ncluding 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 Biologics 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.

3 VIRAGE PHASE 2 DATA UPDATE – AGENDA AND SPEAKERS Introduction to Theriva and VCN - 01 Steven Shallcross - CEO, CFO, Theriva Biologics, Inc. Pancreatic cancer treatment landscape Manuel Hidalgo Medina, MD, PhD – Chief of Hematology and Medical Oncology, Weill Cornell Medicine/New York - Presbyterian Hospital Mike Pishvaian , MD, PhD - Associate Professor of Oncology and Director of Gastrointestinal, Developmental Therapeutics and Clinical Research Programs, Johns Hopkins Kimmel Cancer Center VIRAGE Phase 2b clinical data review Manel Cascallo, PhD – General Director, Theriva Biologics S.L. Questions and answers All speakers Steven Shallcross Manel Cascallo Mike Pishvaian Manuel Hidalgo

4 Theriva Biologics develops unique oncolytic virus therapeutics targeting solid tumors VCN - 01 (zabilugene almadenorepvec)

5 OVERVIEW Financial Snapshot NYSE American Exchange TOVX Ticker $11.6M Cash (12/31/2024) Q3 2025 Projected cash runway 55.8k¹ Average Daily Volume (3M) Rockville, MD / Barcelona, Spain Locations CRC colorectal cancer. HNSCC head and neck squamous cell carcinoma. Rb retinoblastoma. SoC standard of care. ICI Immune checkpoint inhibitors. ¹At 28Apr2025 Yahoo! Finance VCN - 01 Completed Phase 2b clinical trial in first - line metastatic pancreatic cancer in combination with SoC chemotherapy VCN - 01 Phase 1 clinical trials support multiple additional indications (CRC, HNSCC, Rb) and combinations (ICI & CAR - T cells) VCN - X innovative oncolytic virus discovery engine enabling development of a distinct product pipeline

6 THERIVA PIPELINE *Based on Management’s current beliefs and expectations. aGVHD acute graft - vs - host disease; allo - HCT allogeneic hematopoietic ce ll transplant. CSR clinical study report. HNSCC head and neck squamous cell carcinoma. IV intravenous. IVit intravitreal. ¹Final Phase 1b/2a study cohort contingen t on grant funding or partnership. ² Seeking partnership or out - licensing for further development. Status* Sites Phase 3 Phase 2 Phase 1 Pre - IND Target Candidate Phase 2b enrollment complete Orphan Drug Designation US, EU Fast Track Designation US Multicenter Spain, USA Pancreatic Cancer (IV) with gemcitabine/nab - paclitaxel VCN - 01 Selective, Stroma Degrading OV Phase 1 Complete, CSR in preparation Orphan Drug Designation US, EU Rare Pediatric Disease Designation US Retinoblastoma (IVit) Phase 1 Complete, CSR in preparation HNSCC (IV) + durvalumab Phase 1 Study On - going Brain tumors (IV) Preclinical Studies On - going Solid tumors (IV) VCN - X and Albumin Shield OVs Phase 1b/2a On - going Prevention of aGVHD in allo - HCT SYN - 004 [1] Oral β - lactamase Phase 1 Studies Complete Potential indications include NAFLD/NASH, celiac, radiation enteritis SYN - 020 [2] Oral IAP

7 VCN - 01 IS A UNIQUELY ENGINEERED HUMAN ADENOVIRUS 5 High dose, highly replicating virus designed to destroys cancer cells Replication enhanced by significantly increased E2F binding. E1a - δ24 gene deletion means replication only in cells with a defective Rb - E2F pathway. Fiber shaft RGDK modification. PH20 soluble human testicular hyaluronidase enzyme expression is under control of the virus major la te promoter (MLP). Systemic Selective Stroma Degrading E2F binding +++  E1a - Δ24  MLP  PH20 -- RGDK VCN - 01 targets both primary and metastatic lesions Replicating virus expresses PH20 hyaluronidase Exposes solid tumors to the immune system and co - administered therapies Virus replicates only in tumor cells Liver detargeted

8 VCN - 01 IS A UNIQUELY ENGINEERED HUMAN ADENOVIRUS 5 Cancer Associated Fibroblast Stroma Tumor Surrounded by STROMA VCN - 01 1 SYSTEMIC delivers VCN - 01 to the primary tumor and metastases and detargets the liver SELECTIVE replication at very high levels lyses tumor cells directly without harming healthy tissues 2

9 VCN - 01 DESIGNED TO HAVE MULTIPLE ANTI - TUMOR ACTIONS PH20 PH20 PH20 PH20 PH20 PH20 PH20 PH20 Neoantigen Cancer Associated Fibroblast Stroma STROMA degradation by PH20 facilitates solid tumor access and destruction by coadministered cancer therapies 3 4 IMMUNOGENIC actions of VCN - 01 turn “cold” tumors “hot” and elicit an anti - tumor immune response VCN - 01 nab - paclitaxel gemcitabine T - Cells Tumor Stroma Degraded

10 VCN - 01 EXTENSIVE CLINICAL PROGRAM 142 patients treated with VCN - 01 to date in multiple indications and combinations HEAD & NECK – IV + Durvalumab (20) PANCREATIC - IV + Gemcitabine / Abraxane ® Phase 1 (26) and Phase 2b (53)* COLORECTAL – IV Alone (15) PANCREATIC - IT + Gemcitabine / Abraxane ® (8) PANCREATIC, OVARIAN - IV + huCART - meso cells (9)* BRAIN TUMORS – IV (1)* HEAD & NECK – IV alone (1) *On - going study. Abraxane® - nab - paclitaxel. Durvalumab (IMFINZI ® , AstraZeneca) is an anti - PD - L1 mAb immune checkpoint inhibitor. huCART - meso are autologous T cells engineered to express an extracellular single chain variable fragment (scFv) with mesothelin specificity. IT - intratumoral. IV - intravenous. IVit - intravitreal. Rb - retinoblastoma. See Appendix for study registry numbers and publications. Rb – IVit alone (9) (Number of VCN - 01 Patients Treated in Parentheses) Lead Indication for Phase 3

PANCREATIC CANCER TREATMENT LANDSCAP E

12 (m)FOLFIRINOX, NALIRIFOX (ECOG 0 - 1) Gemcitabine + nab - Paclitaxel (ECOG 0 - 2) S ingle agent gemcitabine, capecitabine, 5 - FU (ECOG 3 - 4) PANCREATIC CANCER CURRENT TREATMENTS ¹Bengtsson (2020) Sci Rep 10: 16425. ²Used in <20% of PDAC cases. ³Identical to first - line chemotherapy. CPI checkpoint inhibitor for cancers with microsatellite instability or deficient mismatch repair. ECOG Eastern Cooperative Oncology Group Performance Status. (m)FOLFI RIN OX (modified) leucovorin+5 - FU+irinotecan+oxaliplatin. nab - Paclitaxel nanoparticle albumin - bound paclitaxel. NALIRIFOX leucovorin+ 5 - FU+liposom al irinotecan+oxaliplatin . Adapted from Tempero (2021) J Natl Compr Canc Netw 19: 439. Resectable Borderline Resectable Metastatic / Recurrent (unresectable) Locally Advanced (unresectable) FOLFIRINOX Gemcitabine + nab - Paclitaxel 5 - FU + leucovorin + liposomal i rinotecan Radiotherapy if increases resection margins² Neoadjuvant³ Gemcitabine ± erlotinib , single agent capecitabine or 5 - FU; ± CPI Stage I (5%) Stage II (28%) Stage III (11%) Stage IV (56%) Progression or Recurrence after 1 st Line First - Line Treatments Additional treatment s are available for small subsets of patients with gene mutations such as gBRCAm , NRG1 fusion Status Staging¹

VCN - 01 IN METASTATIC PANCREATIC CANCER

14 VCN - 01 LEAD INDICATION PANCREATIC CANCER Highly fatal cancer protected by dense tumor stroma • Orphan disease, highest mortality of all solid tum ors • Median survival 8 - 11 months for metastatic disease 1,2 • USA est. 6 6,440 new cases and 51,750 deaths in 2024 3 • Hyaluronic acid in stroma is associated with reduced treatment efficacy and poor prognosis 4 • VCN - 01 designed to degrade hyaluronic acid • Incidence is growing worldwide • Est. treatment market ~$2.9B (2024) ~$6.0B (2030) 5 ¹ Michael (2019) BMC Palliat Care 18:13, Bengtsson (2020) Sci Rep 10:16425, Carioli (2021) Ann Oncol 32:478, ASCO Pancreatic Cancer Statistics . ² SEER Cancer Stat Facts: Pancreatic Cancer website . ³ American Cancer Society. Cancer Facts & Figures 2024. Atlanta: American Cancer Society; 2024. ⁴ Tahkola (2021) Sci Rep 11:12216, Placencio - Hickok (2022) Pancreatology 22:92. ⁵Grand View Research website . Pancreatic adenocarcinoma resected from the pancreas body and tail

15 PREFERRED VCN - 01 DOSING REGIMEN ESTABLISHED IN PHASE 1 Dose escalation in patients with metastatic pancreatic cancer ¹Single dose of VCN - 01 administered by 10 min IV infusion. ²nab - Paclitaxel (Abraxane®; 30 min infusion) administered at least 4 hours after VCN - 01. ³Gemcitabine (30 min infusion) administered immediately after Abraxane® infusion. Garcia - Carbonero (2022) J Immunother Cancer 10:e003255. [NCT02045602] SoC standard of care. SEQUENTIAL | 36 | 29 | 22 | 15 | 8 | 1 Cycle 1 Day VCN - 01 (1x10 13 vp) ¹ nab - Paclitaxel ² Gemcitabine ³ Repeat SoC chemotherapy 28 - day cycles starting Day 36 Encouraging clinical profile Primary AEs fever, flu - like illness, reversible increase in liver enzymes Survival and response rates better than published results for gemcitabine/nab - paclitaxel SoC Clinical evidence of proposed MOA VCN - 01 viral genomes and increased immune markers detected in tumor biopsies VCN - 01 tumor penetration and replication indicated by persistent systemic PH20

16 V IR AGE PANCREATIC CANCER PHASE 2B CLINICAL TRIAL Multicenter, open - label, randomized, controlled trial (NCT05673811) • Patients with newly - diagnosed metastatic pancreatic ductal adenocarcinoma ( first line ) • Direct comparison of up to two doses of VCN - 01 with gemcitabine/nab - paclitaxel standard of care (SoC) chemotherapy to SoC chemotherapy alone (randomized 1:1) • Primary endpoints overall survival , VCN - 01 AE profile and tolerability • Secondary endpoints include progression free survival , duration of response Study designed with 80% power to detect a hazard ratio (HR) of 0.65 for OS with a 1 - sided alpha of 0.05 (2 - sided alpha 0.1). P - values are for 2 - sided statistical analysis using the log rank test .

17 V IR AGE ENROLLMENT Total USA Spain Parameter 17 7 10 Sites Open 171 40 131 Screened 59 (35%) 17 (43%) 42 (32%) Screen Failure 112 23 89 Randomized 55 11 44 SoC 57 12 45 VCN - 01 + SoC Treated* 48 7 41 SoC 48 9 39 VCN - 01 + SoC Standard of care (SoC) is gemcitabine / nab - paclitaxel chemotherapy in repeated 28 - day cycles *Patients received at least one dose of SoC in each arm and comprise the Full Analysis Set Five (5) additional patients received one dose of VCN - 01 but no doses of SoC and are included in the Safety P opulation

18 V IR AGE BASELINE DEMOGRAPHICS Patients who received at least one dose of SoC in each Arm (FAS) Full analysis set (FAS) for ARM I includes patients who received at least one dose of gemcitabine/nab paclitaxel SoC chemotherapy; FAS for ARM II includes patients who received VCN - 01 followed 1 week later by at least one dose of gemcitabine/nab paclitaxel SoC chemotherapy. 70.8% of patients in the VCN - 01+SoC arm received 2 doses of VCN - 01. Combined (n=96) VCN - 01 + SoC (n=48) SoC (n=48) Statistics 96 48 48 n Age (years) 67.8 (8.75) 66.0 (8.97) 69.5 (8.25) Mean (SD) 67.5 66.0 68.5 Median Gender 45 (46.9) 23 (47.9) 22 (45.8) n (%) Male 51 (53.1) 25 (52.1) 26 (54.2) n (%) Female ECOG at randomization 36 (37.5) 19 (39.6) 17 (35.4) n (%) 0 60 (62.5) 29 (60.4) 31 (64.6) n (%) 1 Body Mass Index (kg/m 2 ) 24.76 (3.992) 23.84 (3.502) 25.69 (4.265) Mean (SD) 24.05 23.70 25.65 Median

19 Grade 3 - 4 All Grades Preferred Term – No. Patients (%) a,b Second Dose (n=36) First Dose (n=53) Second Dose (n=36) First Dose (n=53) - 1 (1.9%) 19 (52.7%) 31 (58.5%) Pyrexia - - 6 (16.6%) 16 (30.2%) Nausea 1 (2.8%) 1 (1.9%) 4 (11.1%) 15 (28.3%) Asthenia - - 9 (25.0%) 14 (26.4%) Vomiting - 5 (9.4%) 1 (2.7%) 10 (18.9%) Aspartate aminotransferase increased - 4 (7.5%) 1 (2.7%) 9 (16.9%) Alanine aminotransferase increased - 7 (13.2%) 1 (2.7%) 9 (16.9%) Influenza like illness - 4 (7.5%) 2 (5.5%) 8 (15.1%) Transaminases increased - 1 (1.9%) 1 (2.7%) 7 (13.2%) Platelet count decreased/Thrombocytopenia - - 1 (2.7%) 7 (13.2%) Decreased appetite - - 3 (5.5%) 7 (13.2%) Diarrhea - - - 5 (9.4%) Fatigue - - 7 (19.4%) 5 (9.4%) Chills - 3 (5.7%) 1 (2.7%) 4 (7.5%) Lymphocyte count decreased - 3 (5.7%) - 4 (5.7%) Gamma - glutamyl transferase increased - 1 (1.9%) - 3 (5.7%) Anemia - - 2 (5.5%) 3 (5.7%) Cytokine release syndrome a Number of patients and b percentage of patients dosed presenting the treatment related adverse event ( TEAE ) . Note: events with a temporal continuity are accounte d as only one with the highest grade V IR AGE TREATMENT EMERGENT ADVERSE EVENTS VCN - 01 related events occurring in ≥5% of patients Additional Grade 3/4 AEs occurring <5% Treatment - induced liver injury 2 (3.8%) Neutrophil count decreased 1 (1.9%) Lipase increased 1 (1.9%) Alkaline phosphatase increased 1 (1.9%) Neutropenia 1 (1.9%) Hypotension 1 (1.9%)

20 • VIRAGE clinical data was reviewed on two occasions by an independent Data Monitoring Committee (DMC) who noted the following: • Intravenous VCN - 01 was well tolerated in patients treated in this study • The most common VCN - 01 related AEs (pyrexia, flu - like illness, vomiting, nausea, and elevated transaminases) were transient and reversible. • AEs were observed to be less frequent and of reduced CTCAE grade after the second VCN - 01 dose compared to the first VCN - 01 dose • The overall type and number of AEs in the VCN - 01+SoC treatment group was as expected for the pancreatic cancer population, the duration of treatment, and the administration of an oncolytic virus V IR AGE SAFETY REVIEW BY INDEPENDENT DMC

21 INCREASED PROGRESSION - FREE SURVIVAL IN VCN - 01+SOC ARM Adj HR (95% CI) Median (95% CI) Events / Total Treatment Arm Ref. 4.6 (3.5 - 6.5) 41 / 48 SoC 0.55 (0.34 - 0.88) 7.0 (4.8 - 11.2) 33 / 48 VCN - 01 + SoC Logrank P - value: 0.0105 + Censor Based on CT scan evaluation by sites. Data are for the Full Analysis Set (FAS) which comprises patients who received at least 1 dose of gemcitabine/nab - paclitaxel (SoC) chemotherapy in each arm. 70.8% of patients in the VCN - 01+SoC arm received 2 doses of VCN - 01. SoC VCN - 01 + SoC

22 INCREASED OVERALL SURVIVAL IN VCN - 01+SOC ARM Data are for the Full Analysis Set (FAS) which comprises patients who received at least 1 dose of gemcitabine/nab - paclitaxel (SoC) chemotherapy in each arm. 70.8% of patients in the VCN - 01+SoC arm received 2 doses of VCN - 01. SoC VCN - 01 + SoC Adj HR (95% CI) Median (95% CI) Events / Total Treatment Arm Ref. 8.6 (6.9 - 11.6) 35 / 48 SoC 0.57 (0.34 - 0.96) 10.8 (7.4 - 15.8) 27 / 48 VCN - 01 + SoC Logrank P - value: 0.0546 + Censor

23 DURATION OF RESPONSE DOUBLED IN VCN - 01+SOC ARM Based on CT scan evaluation by sites. Data are for the Full Analysis Set (FAS) which comprises patients who received at least 1 dose of gemcitabine/nab - paclitaxel (SoC) chemotherapy in each arm. SoC VCN - 01 + SoC Adj HR (95% CI) Median (95% CI) Events / Total Treatment Arm Ref. 5.4 (2.0 - 6.8) 11 / 15 SoC 0.22 (0.08 - 0.62) 11.2 (7.4 - NE) 7 / 19 VCN - 01 + SoC Logrank P - value: 0.0035 + Censor

24 V IR AGE ANALYSIS OF PTS RECEVING TWO VCN - 01 DOSES Evaluate the impact of the second VCN - 01 dose • Measure OS and PFS in patients who initiate the 4 th treatment cycle • ARM I: Cycle 4 of gemcitabine/nab - paclitaxel SoC • ARM II: Second dose of VCN - 01 followed by Cycle 4 of gemcitabine/nab - paclitaxel SoC OS overall survival. PFS progression free survival VCN - 01 2 Doses Analysis

25 V IR AGE DEMOGRAPHICS PTS RECEIVING TWO VCN - 01 DOSES Comparison of patients who started the 4 th treatment cycle Analysis compares patients in ARM II who received a second dose of VCN - 01 followed 1 - week later by the 4 th treatment cycle of gemcitabine/nab - paclitaxel SoC to patients in ARM I who started the 4 th treatment cycle of gemcitabine/nab - paclitaxel SoC. Combined VCN - 01 + SoC SoC Statistics 63 (65.6) 34 (70.8) 29 (60.4) n (%) No. Patients (% of cohort) 66.9 (9.09) 65.8 (9.71) 68.1 (8.31) Mean (SD) Age (years) 66.0 66.0 66.0 Median Gender 30 (47.6) 17 (50.0) 13 (44.8) n (%) Male 33 (52.4) 17 (50.0) 16 (55.2) n (%) Female ECOG at randomization 29 (46.0) 15 (44.1) 14 (48.3) n (%) 0 34 (54.0) 19 (55.9) 15 (51.7) n (%) 1 Body Mass Index (kg/m 2 ) 24.31 (3.547) 23.78 (3.707) 24.94 (3.304) Mean (SD) 23.70 23.65 25.60 Median

26 IMPROVED PFS IN PTS RECEIVING TWO VCN - 01 DOSES PFS progression free survival. Based on CT scan evaluation by sites. Analysis compares patients in ARM II who received a second dose of VCN - 01 followed 1 - week later by the 4 th treatment cycle of gemcitabine/nab - paclitaxel SoC to patients in ARM I who started the 4 th treatment cycle of gemcitabine/nab - paclitaxel SoC. SoC VCN - 01 2 doses + SoC Adj HR (95% CI) Median (95% CI) Events / Total Treatment Arm Ref. 7.4 (5.7 - 8.4) 22 / 29 SoC 0.48 (0.25 - 0.91) 11.2 (7.3 - 16.6) 19 / 34 VCN - 01 x 2 + SoC Logrank P - value: 0.0173 + Censor

27 IMPROVED OS IN PTS RECEIVING TWO VCN - 01 DOSES OS overall survival. Analysis compares patients in ARM II who received a second dose of VCN - 01 followed 1 - week later by the 4 th treatment cycle of gemcitabine/nab - paclitaxel SoC to patients in ARM I who started the 4 th treatment cycle of gemcitabine/nab - paclitaxel SoC. SoC VCN - 01 2 doses + SoC Adj HR (95% CI) Median (95% CI) Events / Total Treatment Arm Ref. 11.6 (8.6 - 12.8) 19 / 29 SoC 0.44 (0.21 - 0.92) 14.8 (10.6 - NE) 15 / 34 VCN - 01 x 2 + SoC Logrank P - value: 0.0460 + Censor

28 • Enrolled a “real world” population of older and more fragile patients • Acceptable AE profile consistent with prior VCN - 01 clinical trials • Increased OS, PFS, and DoR in VCN - 01 plus gemcitabine/nab - paclitaxel SoC treatment group compared to SoC alone • Hazard ratios for OS (0.57), PFS (0.55), and DoR (0.22) compare favorably to values reported for Phase 3 trial comparing NALIRIFOX with gemcitabine/nab - paclitaxel (0.83, 0.69, and 0.67 respectively)¹ • Second VCN - 01 dose appears to confer additional survival benefit • Regulatory advice received (FDA, EMA) on potential pivotal trial design • Orphan Drug Designation (FDA, EMA) and Fast Track Designation (FDA) V IR AGE RESULTS SUPPORT VCN - 01 PHASE 3 TRIAL IN PDAC DoR duration of response. OS overall survival. PFS progression free survival. NALIRIFOX leucovorin+ 5 - FU+liposomal irinotecan+oxaliplatin . ¹Wainberg (2023) Lancet 402:1272; median age 65 years, ECOG 1 57% in NALIRIFOX group.

29 QUESTIONS AND ANSWERS Steven Shallcross CEO, CFO, Theriva Biologics, Inc. Manuel Hidalgo Medina, MD, PhD Chief of Hematology and Medical Oncology, Weill Cornell Medicine/New York - Presbyterian Hospital Mike Pishvaian , MD, PhD Associate Professor of Oncology and Director of Gastrointestinal, Developmental Therapeutics and Clinical Research Programs, Johns Hopkins Kimmel Cancer Center Manel Cascallo, PhD General Director, Theriva Biologics S.L.

APPENDIX

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