Exhibit 99.1

Theriva™ Biologics to Present Preclinical Data Supporting the Potential Synergy of VCN-01 and First-Line Pancreatic Cancer Chemotherapy Regimens at the American Society for Cell and Gene Therapy 27th Annual Meeting

– Lead product candidate, VCN-01 in combination with liposomal irinotecan demonstrated enhanced anti-tumor effects in a human pancreatic mouse xenograft–

– The observed synergy emphasizes VCN-01’s potential in diverse chemotherapy combinations for improved efficacy in the treatment of pancreatic cancer–

Rockville, MD, April 22, 2024 – 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 announced the presentation of preclinical data demonstrating enhanced anti-tumor effects in human pancreatic cancer xenograft-bearing mice treated with lead product candidate VCN-01 and liposomal irinotecan. These data support the potential synergy of VCN-01 and first-line pancreatic cancer chemotherapy regimens, and will be featured in a poster presentation at the American Society for Cell and Gene Therapy (ASGCT) 27th Annual Meeting, being held both virtually and in Baltimore from May 7-11, 2024.

“The data featured at the upcoming ASGCT meeting build on recent findings that suggest the combination of VCN-01 and topoisomerase I inhibitors, such as liposomal irinotecan, may provide a synergistic antitumor effect to improve therapeutic outcomes across indications,” said Steven A. Shallcross, Chief Executive Officer of Theriva Biologics. “We look forward to leveraging these findings and evaluating the combination of VCN-01 with additional first-line pancreatic cancer chemotherapy regimens, including NALIRIFOX and FOLFIRINOX. In parallel, we continue to progress our on-going VIRAGE Phase 2b trial evaluating VCN-01 in combination with gemcitabine/nab-paclitaxel to treat metastatic pancreatic ductal adenocarcinoma (PDAC). Together, these important steps bring us one step closer to building a portfolio of potentially improved therapeutic combinations for PDAC patients with high unmet medical needs.”

Key takeaways include:

Overview: The combination of VCN-01 + topoisomerase I (topo1) inhibitors, such as liposomal irinotecan, has a tolerable toxicity profile and may improve efficacy in the treatment of human pancreatic cancer.

The full abstract (1760) for the poster presentation is accessible on the ASGCT Congress portal and the poster will be available starting, Friday, May 10, 2024. Additional details on the poster are provided below:

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 is advancing 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 candidates are: (1) VCN-01, 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 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 potential synergy between lead product candidate, VCN-01 and first-line pancreatic cancer chemotherapy regimens; the suggestion that the combination of VCN-01 and topoisomerase I inhibitors, such as liposomal irinotecan, may provide a synergistic antitumor effect to improve therapeutic outcomes across indications; leveraging these findings and evaluating the combination of VCN-01 with the additional first-line pancreatic cancer chemotherapy regimens, including NALIRIFOX and FOLFIRINOX; and continuing to progress our on-going VIRAGE Phase 2b trial evaluating VCN-01 in combination with gemcitabine/nab-paclitaxel to treat metastatic pancreatic ductal adenocarcinoma (PDAC). Important factors that could cause actual results to differ materially from current expectations include, among others, the ability to generate clinical data that establishes a synergy between lead product candidate, VCN-01 and first-line pancreatic cancer chemotherapy regimen and provides an antitumor effect; the Company’s and VCN’s product candidates 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; 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 and VCN’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 and VCN’s products, developments by competitors that render such products obsolete or non-competitive, the Company’s and VCN’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, 2023 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:

Chris Calabrese
LifeSci Advisors, LLC
ccalabrese@lifesciadvisors.com
917-680-5608

Source: Theriva Biologics, Inc.

Exhibit 99.2

2024 ASGCT Abstract, version 4

Section F2: Cancer: Oncolytic Viruses

Title: Enhanced Anti-Tumor Efficacy of Combination Therapy with the Oncolytic Adenovirus, VCN-01, and Liposomal Irinotecan in Human Pancreatic Mouse Xenografts

Authors: Maria V. Maliandi1, Paz Moreno1, Ramon Alemany1,2, Manel Cascallo1, Sheila Connelly3, Ana Mato-Berciano1

Affiliations: 1Theriva Biologics, S.L., Barcelona, Spain, 2Catalan Institute of Oncology (ICO), L’Hospitalet de Llobregat, Barcelona, Spain, 3Theriva Biologics, Inc., Rockville, MD, USA.

VCN-01 is a clinical-stage oncolytic adenovirus engineered to replicate selectively in cancer cells with an aberrant RB1-E2F pathway. The VCN-01 E1A promoter is modified by inclusion of eight E2F1 binding sites and a 24-bp deletion that promotes viral transcription in cells with elevated free E2F1 and renders the virus replication-deficient in RB1-functional, normal cells. Here, human pancreatic cancer cell lines were exposed to topoisomerase I (topo1) inhibiting chemotherapeutics, irinotecan (IRI), its active metabolite, SN-38, and topotecan (topo; see Figure A). Notably, in NP-18 cells, E2F1 mRNA was increased ~3-fold compared to untreated cells, and E1A mRNA was boosted ~5-fold in cells treated with VCN-01 + topo1 inhibitors compared to VCN-01 alone. These data suggest topo1 inhibitor-mediated elevations in E2F1 increase VCN-01 transcription. Based on these promising in vitro results, potential synergy of VCN-01 plus the liposomal formulation of IRI (nal-IRI) was tested in animals bearing subcutaneous human pancreatic tumors . After tumors were established, indicated animals were treated with a single IV dose of VCN-01 (4x1010 vp) or PBS (day 1). Designated animals in each group were then treated with either PBS or nal-IRI (IP) on days 3, 10 and 17. In animals with NP-18 tumors, treatment with VCN-01 or Nal-IRI alone at both the 10 mg/kg and 5 mg/kg doses resulted in significant tumor growth inhibition compared to PBS (see Figure B). Importantly, combination therapy with VCN-01 + nal-IRI at either dose displayed significantly reduced tumor growth compared to each treatment alone. qPCR analyses performed on tumors collected at end of study confirmed the presence of viral genomes and E1A mRNA suggesting intratumoral viral replication and indicating ongoing transcriptional activity of VCN-01. Preliminary analyses suggest that combination therapy with VCN-01 + nal-IRI has a tolerable toxicity profile. These data are consistent with the hypothesis that topo1 inhibitors increase cellular E2F1 protein expression resulting in upregulation of the modified VCN-01 E1A promoter thereby enhancing viral gene expression and improving anti-tumor efficacy. The combination of VCN-01 + topo1 inhibitors, such as Nal-IRI, may demonstrate improved efficacy in the treatment of human pancreatic cancer.

[See Figure below]