VCN-11

– The independent data monitoring committee (IDMC) recommended the continuation of VIRAGE, the Phase 2b clinical trial of VCN-01 in combination with chemotherapy for metastatic Pancreatic Ductal Adenocarcinoma (PDAC), with no safety concerns raised - - VIRAGE remains on track to complete enrollment in the first half of 2024- - As of December 31, 2023, Theriva Biologics reports $23.2 million in cash, which is expected to provide runway into the first quarter of 2025 - - Conference call and webcast to be held on Monday, March 25 at 8:30 a.m. ET - ROCKVILLE, Md., March 25, 2024 (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 full-year ended December 31, 2023, and provided a corporate update. “With continued advancement of our clinical programs, we have the opportunity to achieve several important milestones this year,” said Steven A. Shallcross, Chief Executive Officer of Theriva Biologics. “VIRAGE, our Phase 2b trial of VCN-01 in newly-diagnosed metastatic PDAC remains on track to complete enrollment in the first half of 2024. We completed the first safety review with the IDMC, and with a positive recommendation, VIRAGE will continue to enroll patients as planned with no modifications to the protocol. Our clinical data has demonstrated that repeated systemic dosing of VCN-01 is feasible from a safety perspective, and will now focus on determining whether the repeated-dose regimen of VCN-01 may lead to improved clinical outcomes for patients with PDAC and other solid cancers. In addition to advancing the VIRAGE PDAC trial, we continue to work closely with key opinion leaders, and regulatory agencies to refine our protocol and clinical strategy for VCN-01 as an adjunct to chemotherapy in pediatric patients with advanced retinoblastoma. In parallel, our investigator sponsored Phase 1 trial evaluating the safety and activity of intravitreal VCN-01 in pediatric patients with refractory retinoblastoma continues to progress and will further inform our clinical development pathway in this area of high unmet need.” Recent Program Highlights and Anticipated Milestones: VCN-01: Pancreatic Ductal Adenocarcinoma (PDAC): Dosing is underway and enrollment continues to progress for VIRAGE, the randomized, controlled, multicenter, open-label Phase 2b trial of VCN-01 in combination with standard-of-care chemotherapy (gemcitabine/nab-paclitaxel) as a first line therapy in newly diagnosed bmetastatic PDAC patients. The trial is expected to enroll 92 evaluable patients and remains on track to complete enrollment in H1 2024. The Independent Data Monitoring Committee (IDMC) recommended the continuation of enrollment as planned into the VIRAGE study. According to the IDMC's expert assessment of clinical data from patients enrolled at six sites open in the U.S. and nine sites in Spain, the ongoing Phase 2b trial will continue without any changes to the protocol. No safety concerns were raised based on the evaluation of data presented at the IDMC meeting. Intravenous VCN-01 has been well tolerated and demonstrated a safety pro with prior clinical trials. Importantly, no additional toxicities were observed in patients receiving a second dose of VCN-01. Retinoblastoma: The investigator sponsored Phase 1 trial evaluating the safety and activity of intravitreal VCN-01 in pediatric patients with refractory retinoblastoma has completed patient treatment. The trial is designed to evaluate escalating doses of VCN-01 administered by two intravitreal injections separated by 14 days. The investigator sponsored Phase 1 trial, which will complete patient follow-up in H1 2024, will help inform the planned Phase 2 trial design. This builds on positive preclinical results presented by collaborators at Fundació Sant Joan de Déu demonstrating that administration of VCN-01 in combination with topotecan chemotherapy may improve VCN-01 activity against retinoblastoma. SYN-004 (ribaxamase): Dosing is underway for the ongoing Phase 1b/2a randomized, double-blinded, placebo-controlled clinical trial of SYN-004 (ribaxamase) in allogeneic hematopoietic cell transplant (HCT) recipients for the prevention of acute graft-versus-host-disease (aGVHD). SYN-004 appeared to be well tolerated in HCT patients treated with IV meropenem and SYN-004 was not detected in blood samples from the majority of the evaluable patients. The trial is on track to complete enrollment into the second cohort in Q2 2024. Business Updates On November 2, 2023, Theriva signed an exclusive option to license intellectual property from Sant Joan de Déu-Barcelona Children’s Hospital (SJD) to explore the therapeutic potential of VCN-01 in combination with topoisomerase I inhibitors. This strengthens a long-term research collaboration with SJD and builds on ongoing trial evaluating VCN-01 in pediatric cancers. Theriva is actively pursuing licensing discussions for our SYN-020 intestinal alkaline phosphatase asset. Full-Year Ended December 31, 2023 Financial Results General and administrative expenses decreased to $7.1 million for the year ended December 31, 2023, from $9.9 million for the year ended December 31, 2022. This decrease of 28% is primarily comprised of the decrease in the fair value of the contingent consideration of $2.8 million, along with lower salary, investor relations, legal costs, consulting fees related to the VCN acquisition, and director and officer insurance offset by higher audit fees, and other consulting fees. The charge relating to stock based compensation expense was $0.4 million for the year ended December 31, 2023, compared to $0.4 million for the year ended December 31, 2022. Research and development expenses increased to $14.3 million for the year ended December 31, 2023, from $11.7 million for the year ended December 31, 2022. This increase of 22% is primarily the result of higher clinical trial expenses related to our VIRAGE Phase 2 clinical trial of VCN-01 in PDAC, offset by lower expenses related to our Phase 1b/2a clinical trial of SYN-004 (ribaxamase) in allogeneic HCT recipients, the completed Phase 1a clinical trial of SYN-020, decreased manufacturing expenses related to our Phase 1a clinical trial of SYN-020 and lower other indirect costs. We anticipate research and development expense to increase as we continue enrollment in our VIRAGE Phase 2 clinical trial of VCN-01 in PDAC and our ongoing Phase 1 clinical trial in retinoblastoma, expand GMP manufacturing activities for VCN-01, and continue supporting our VCN-11 and other preclinical and discovery initiatives. Research and development expenses also include a charge relating to non-cash stock-based compensation expense of $165,000 for the year ended December 31, 2023, compared to $112,000 for the year ended December 31, 2022. In addition, we expect research and development expenses to increase as we incur higher clinical program costs for our VCN product candidates. Other income was $1,442,000 for the year ended December 31, 2023, compared to other income of $471,000 for the year ended December 31, 2022. Other income for the year ended December 31, 2023 is primarily comprised of interest income of $1,439,000 and an exchange gain of $3,000. Other income for the year ended December 31, 2022 is primarily comprised of interest income of $512,000 offset by an exchange loss of $41,000. Cash and cash equivalents totaled $23.2 million as of December 31, 2023, compared to $41.8 million as of December 31, 2022. The audited financial statements for the year ended December 31, 2023 included in the Company’s Annual Report on Form 10-K contain an unqualified audit opinion from the Company’s independent registered public accounting firm that includes an explanatory paragraph related to the Company's ability to continue as a going concern. Conference Call Theriva Biologics will host a conference call on Monday, March 25, 2024 at 8:30 a.m. ET to discuss its financial results for the full-year ended December 31, 2023 and provide a corporate update. Individuals may participate in the live call via telephone by dialing 1-877-451-6152 (domestic) or 1-201-389-0879 (international) and using the conference ID: 13744453. Participants are asked to dial in 15 minutes before the start of the call to register. Investors and the public can access the live and archived webcast of this call via the “News & Media” section of the company’s website, , under “Events” or by clicking here, up to 90 days after the call. 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 . 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 VIRAGE remaining on track to complete enrollment in the first half of 2024, cash being expected to provide runway into the first quarter of 2025, continued advancement of the Company’s clinical programs providing the opportunity to achieve several important milestones this year, VIRAGE remaining on track to complete enrollment in the first half of 2024, VIRAGE continuing to enroll patients as planned with no modifications to the protocol, determining whether the repeated-dose regimen of VCN-01 may lead to improved clinical outcomes for patients with PDAC and other solid cancers, continuing to work closely with key opinion leaders, and regulatory agencies to refine our protocol and clinical strategy for VCN-01 as an adjunct to chemotherapy in pediatric patients with advanced retinoblastoma, the Company investigator sponsored Phase 1 trial evaluating the safety and activity of intravitreal VCN-01 in pediatric patients with refractory retinoblastoma further informing the Company’s clinical development pathway in this area of high unmet need, the VIRAGE trial enrolling 92 evaluable patients, completing patient follow-up in Q1 2024 in the investigator sponsored Phase 1 trial evaluating VCN-01 in pediatric patients with refractory retinoblastoma, the SYN-004 trial being on track to complete enrollment in the second cohort in Q2 2024 and expected increases in research and development expenses as the Company incurs higher clinical program costs for its VCN product candidates. Important factors that could cause actual results to differ materially from current expectations include, among others, the Company’s and VCN’s ability to reach clinical milestones when anticipated, including the ability to continue to enroll patients as planned and the completion of enrollment in Virage in the first half of 2024, completion of patient follow- up in Q1 2024 in the investigator sponsored Phase 1 trial patient evaluating VCN-01 in pediatric patients with refractory retinoblastoma, and completing enrollment in the SYN-004 second cohort in Q2 of 2024, generating clinical data that establishes VCN-01 may lead to improved clinical outcomes for patients with PDAC and other solid cancers; 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 the cash providing a runway into the first quarter of 2025, 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. Theriva Biologics, Inc. and Subsidiaries Consolidated Balance Sheets (In thousands except share and par value amounts) (Unaudited) December 31, December 31, 2023 2022 Assets Current Assets Cash and cash equivalents $ 23,177 $ 41,786 Tax credit receivable 1,812 — Prepaid expenses and other current assets 2,414 3,734 Total Current Assets 27,403 45,520 Non-Current Assets Property and equipment, net 422 345 Restricted cash 102 99 Right of use asset 1,759 1,199 In-process research and development 19,755 19,150 Goodwill 5,700 5,525 Deposits and other assets 78 23 Total Assets $ 55,219 $ 71,861 Liabilities and Stockholders’ Equity Current Liabilities: Accounts payable $ 770 $ 915 Accrued expenses 2,995 1,496 Accrued employee benefits 1,517 1,403 Contingent consideration, current portion — 2,973 Deferred research and development tax credit-current portion 906 — Loans payable-current 63 57 Operating lease liability-current portion 487 216 Total Current Liabilities 6,738 7,060 Non-current Liabilities Non-current contingent consideration 6,274 7,211 Loan Payable - non-current 162 221 Deferred tax liabilities, net — 1,618 Non-current deferred research and development tax credit 906 — Non-current operating lease liability 1,442 1,187 Total Liabilities 15,522 17,297 Commitments and Contingencies — — Temporary Equity Series C convertible preferred stock, $0.001 par value; 10,000,000 authorized;275,000 issued and outstanding 2,006 2,006 Series D convertible preferred stock, $0.001 par value; 10,000,000 authorized;100,000 issued and outstanding 728 728 Stockholders’ Equity: Common stock, $0.001 par value; 350,000,000 shares authorized, 17,868,282 issued and 17,148,049 outstanding at December 31, 2023 and 15,844,061 issued and 15,123,828 outstanding at December 31, 2022 18 16 Additional paid-in capital 346,519 343,750 Treasury stock at cost, 720,233 shares at December 31, 2023 and at December 31, 2022 (288 ) (288 ) Accumulated other comprehensive income (loss) 32 (679 ) Accumulated deficit (309,318 ) (290,969 ) Total Stockholders‘ Equity 36,963 51,830 Total Liabilities and Stockholders’ Equity $ 55,219 $ 71,861 Theriva Biologics, Inc. and Subsidiaries Consolidated Statements of Operations and Comprehensive Loss (In thousands, except share and per share amounts) (Unaudited) For the year ended December 31, 2023 2022 Operating Costs and Expenses: General and administrative $ 7,120 $ 9,858 Research and development 14,311 11,723 Total Operating Costs and Expenses 21,431 21,581 Loss from Operations (21,431 ) (21,581 ) Other Income: Foreign currency exchange gain (loss) 3 (41 ) Interest income 1,439 512 Total Other Income 1,442 471 Net Loss before income taxes (19,989 ) (21,110 ) Income tax benefit 1,640 1,425 Net Loss Attributable to Theriva Biologics, Inc. and Subsidiaries $ (18,349 ) $ (19,685 ) Effect of Warrant exercise price adjustment — (340 ) Net Loss Attributable to Common Stockholders $ (18,349 ) $ (20,025 ) Net Loss Per Share - Basic and Dilutive $ (1.14 ) $ (1.31 ) Weighted average number of shares outstanding during the period - basic and dilutive 16,107,014 15,327,328 Net Loss (18,349 ) (19,685 ) Gain (loss) on foreign currency translation 711 (679 ) Total comprehensive loss (17,638 ) (20,364 )

- VIRAGE, the Phase 2b clinical trial of VCN-01 in combination with chemotherapy for metastatic Pancreatic Ductal Adenocarcinoma remains on track to complete enrollment in the first half of 2024; multiple patients have received second doses of VCN-01, which continues to be well tolerated with a safety profile consistent with prior clinical trials - - Presented survival outcomes data from the Phase 1 investigator-sponsored study evaluating VCN-01 in combination with durvalumab in patients with recurrent/metastatic squamous cell carcinoma of the head and neck at the European Society for Medical Oncology (ESMO) Congress 2023 - - Data from the Phase 1 investigator-sponsored study evaluating VCN-01 in combination with CAR-T cell immunotherapy in patients with pancreatic and serous epithelial ovarian cancer was presented at the Society for Immunotherapy of Cancer’s (SITC) 2023 Annual Meeting - - As of September 30, 2023, Theriva Biologics reports $31.2 million in cash, which is expected to provide runway into the first quarter of 2025 - - Conference call and webcast to be held on Monday, November 13th at 8:30 a.m. ET - ROCKVILLE, Md., Nov. 13, 2023 (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, 2023, and provided a corporate update. “We are encouraged by the growing clinical data that underscores the promise of our systemically administered oncolytic adenovirus and lead program, VCN-01, in key indications and combinations,” said Steven A. Shallcross, Chief Executive Officer of Theriva Biologics. “Data from the ongoing study of VCN-01 in combination with durvalumab in patients with recurrent/metastatic squamous cell carcinoma of the head and neck (R/M HNSCC) were recently presented at the annual ESMO Congress. Results showed enhanced patient survival, which correlated with VCN-01 mediated increases in the CPS (combined positive score for PD-L1 staining), a key determinant of outcomes with anti-PD-(L)1 checkpoint inhibitor therapies. Together with data presented at this year’s SITC meeting, these data further validate the feasibility of combining VCN-01 with immunotherapies.” Mr. Shallcross continued, “We continue to advance VIRAGE, our Phase 2b trial of VCN-01 in newly-diagnosed metastatic pancreatic ductal adenocarcinoma (PDAC), with patients dosed across sites in the U.S. and Spain. We have observed a consistent safety and tolerability profile and remain on track to complete enrollment for VIRAGE in the first half of 2024. As part of our commitment to transforming therapeutic approaches for devastating cancers, we will meet with the FDA before year-end to discuss the development pathway for VCN-01 as an adjunct to chemotherapy in pediatric patients with advanced retinoblastoma. While our key area of focus is on advancing and maximizing the therapeutic potential of VCN-01, we continue to explore opportunities to bolster our pipeline with new oncolytic virus candidates from utilizing our Albumin Shield technology.” Recent Program Highlights and Anticipated Milestones: VCN-01: Dosing is underway and enrollment continues to progress for VIRAGE, the randomized, controlled, multicenter, open-label Phase 2b trial of VCN-01 in combination with standard-of-care chemotherapy (gemcitabine/nab-paclitaxel) as a first line therapy in newly diagnosed metastatic PDAC patients. Dosing at sites across the U.S. and Spain continues and VCN-01 has been well tolerated with a safety profile consistent with prior clinical trials. The trial is expected to enroll 92 patients and remains on track to complete enrollment in H1 2024.The Institut Catala d’Oncologia (ICO) presented Phase 1 data from the investigator-sponsored study evaluating VCN-01 in combination with durvalumab for patients with R/M HNSCC. Encouraging survival was observed in patients progressing to anti-PD(L)-1 agents after systemic VCN-01 in combination with durvalumab. These data were featured in a poster presentation at the ESMO Congress, held both virtually and in Madrid, Spain from October 20-24, 2023. Theriva hosted a virtual KOL event featuring expert oncologist Ricard Mesia, M.D. (Institut Català d'Oncologia / Catalan Institute of Oncology). In addition to reviewing key takeaways from the ESMO poster presentation, Dr. Mesia discussed the unmet medical needs in head and neck cancer, current treatment limitations, and the therapeutic potential of VCN-01 to elicit an extended anti-tumor immune response. The University of Pennsylvania presented initial data from a Phase 1 study evaluating VCN-01 in combination with mesothelin-directed lentiviral transduced human chimeric antigen receptor modified T cells (huCART-meso) in patients with pancreatic and serous epithelial ovarian cancer. Initial results highlight the feasibility of administering VCN-01 with huCART-meso cells to treat solid tumors. These data were featured in a poster presentation at the SITC Annual Meeting, held both virtually and in San Diego, November 1-5, 2023.Additional anticipated milestones: The Company will meet with the FDA before year-end to discuss the clinical development and potential registration pathway for VCN-01 as an adjunct to chemotherapy in pediatric patients with advanced retinoblastoma. SYN-004 (ribaxamase): Dosing is underway for the ongoing Phase 1b/2a randomized, double-blinded, placebo-controlled clinical trial of SYN-004 (ribaxamase) in allogeneic hematopoietic cell transplant (HCT) recipients for the prevention of acute graft-versus-host-disease (aGVHD). SYN-004 appeared to be well tolerated in HCT patients treated with IV meropenem and SYN-004 was not detected in blood samples from the majority of the evaluable patients. The trial is on track to complete enrollment in the second cohort in H1 2024. Third Quarter Ended September 30, 2023 Financial Results General and administrative expenses decreased to $212,000 for the three months ended September 30, 2023, from $2.4 million for the three months ended September 30, 2022. This decrease of 91% is primarily comprised of the decrease in the fair value of the contingent consideration of $1.6 million, along with lower salary and bonus costs, investor relations fees, audit fees, travel, and VCN administrative expenses not included in the prior year, offset by an increase in consulting fees. The charge related to stock-based compensation expense was $95,000 for the three months ended September 30, 2023, compared to $93,000 for the three months ended September 30, 2022. Research and development expenses increased to $4.0 million for the three months ended September 30, 2023, from approximately $2.6 million for the three months ended September 30, 2022. This increase of 56% is primarily the result of higher clinical trial expenses related to our VIRAGE Phase 2 clinical trial of VCN-01 in PDAC, offset by decreased expenses related to our Phase 1b/2a clinical trial of SYN-004 (ribaxamase) in allogeneic HCT recipients, Phase 1a clinical trial of SYN-020, and decreased manufacturing expenses related to our Phase 1a clinical trial of SYN-020. We anticipate research and development expenses to increase as we continue enrollment in our VIRAGE Phase 2 clinical trial of VCN-01 in PDAC and our ongoing Phase 1 clinical trial in retinoblastoma, expand GMP manufacturing activities for VCN-01, and continue supporting our VCN-11 and other preclinical and discovery initiatives. The charge related to stock-based compensation expense was $40,000 for the three months ended September 30, 2023, compared to $28,000 related to stock-based compensation expense for the three months ended September 30, 2022. Other income was $388,000 for the three months ended September 30, 2023 compared to other income of $161,000 for the three months ended September 30, 2022. Other income for the three months ended September 30, 2023 is primarily comprised of interest income of $382,000 and an exchange gain of $6,000. Other income for the three months ended September 30, 2022 is primarily comprised of interest income of $170,000 offset by an exchange loss of $9,000. Cash and cash equivalents totaled $31.2 million as of September 30, 2023, compared to $41.8 million as of December 31, 2022. Conference Call Theriva Biologics will host a conference call on Monday, November 13, 2023, at 8:30 a.m. ET to discuss its financial results for the quarter ended September 30, 2023 and provide a corporate update. Individuals may participate in the live call via telephone by dialing 1-877-451-6152 (domestic) or 1-201-389-0879 (international) and using the conference ID: 13741546. Participants are asked to dial in 15 minutes before the start of the call to register. Investors and the public can access the live and archived webcast of this call via the “News & Media” section of the company’s website, https://www.therivabio.com, under “Events” or by clicking here, up to 90 days after the call. 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 VIRAGE remaining on track to complete enrollment in the first half of 2024, VCN-01 continuing to be well tolerated with a safety profile consistent with prior clinical trials, cash providing a runway into the first quarter of 2025, continuing to advance VIRAGE in newly-diagnosed metastatic PDAC with patients dosed across sites in the U.S. and Spain, the therapeutic potential of VCN-01 to elicit an extended anti-tumor immune response, plans to meet with regulatory agencies before year-end to discuss the development pathway for VCN-01 as an adjunct to chemotherapy in pediatric patients with advanced retinoblastoma, continuing to explore opportunities to bolster the Company’s pipeline with new oncolytic virus candidates from utilizing its Albumin Shield technology, the VIRAGE trial enrolling 92 patients, the SYN-004 trial being on track to complete the second cohort in H1 2024 and research and development expense increasing as the Company continues enrollment in the VIRAGE Phase 2 clinical trial of VCN-01 in PDAC and its ongoing Phase 1 clinical trial in retinoblastoma, expanding GMP manufacturing activities for VCN-01, and continuing supporting our VCN-11 and other preclinical and discovery initiatives. 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 and VCN’s ability to reach clinical milestones when anticipated, including completion of enrollment in Virage in the first half of 2024 and completing the SYN-004 second cohort in the first quarter of 2024, generating clinical data that establishes VCN-01 being an adjunct to chemotherapy in pediatric patients with advanced retinoblastoma and combining with immunotherapy products to treat solid tumors, the Company’s ability to successfully combine and operate the business of the Theriva Biologics and VCN, 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, 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 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 the cash providing a runway into the first quarter of 2025, and other factors described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2022 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 Theriva Biologics, Inc. and Subsidiaries Consolidated Balance Sheets(In thousands except share and par value amounts)(Unaudited) September 30, 2023 December 31, 2022Assets Current Assets Cash and cash equivalents $31,160 $41,786 Tax credit receivable 1,399 — Prepaid expenses and other current assets 2,208 3,734 Total Current Assets 34,767 45,520 Non-Current Assets Property and equipment, net 389 345 Restricted cash 97 99 Right of use assets 1,831 1,199 In-process research and development 18,925 19,150 Goodwill 5,460 5,525 Deposits and other assets 76 23 Total Assets $ 61,545 $ 71,861 Liabilities and Stockholders’ Equity Current Liabilities: Accounts payable $833 $915 Accrued expenses 5,590 1,496 Accrued employee benefits 1,269 1,403 Contingent consideration, current portion — 2,973 Deferred research and development tax credit-current portion 525 — Loans payable-current portion 65 57 Operating lease liability-current portion 461 216 Total Current Liabilities 8,743 7,060 Non-current Liabilities Non-current contingent consideration 5,935 7,211 Non-current loans payable 150 221 Deferred tax liabilities, net 413 1,618 Non-current deferred research and development tax credit 874 — Non-current operating lease liability 1,546 1,187 Total Liabilities 17,661 17,297 Commitments and Contingencies Temporary Equity Series C convertible preferred stock, $0.001 par value; 10,000,000 authorized; 275,000 issued and outstanding 2,006 2,006 Series D convertible preferred stock, $0.001 par value; 10,000,000 authorized; 100,000 issued and outstanding 728 728 Stockholders’ Equity: Common stock, $0.001 par value; 350,000,000 shares authorized, 17,762,998 issued and 17,042,765 outstanding at September 30, 2023 and 15,844,294 issued and 15,124,061 outstanding at December 31, 2022 18 16 Additional paid-in capital 346,312 343,750 Treasury stock at cost, 720,233 shares at September 30, 2023 and at December 31, 2022 (288) (288)Accumulated other comprehensive loss (1,058) (679)Accumulated deficit (303,834) (290,969)Total Stockholders’ Equity 41,150 51,830 Total Liabilities, Temporary Equity, and Stockholders’ Equity $ 61,545 $ 71,861 Theriva Biologics, Inc. and Subsidiaries Consolidated Statements of Operations and Comprehensive Loss(In thousands, except share and per share amounts)(Unaudited) For the three months ended September 30, For the nine months ended September 30, 2023 2022 2023 2022 Operating Costs and Expenses: General and administrative 212 2,416 5,099 5,612 Research and development 4,006 2,570 10,115 8,652 Total Operating Costs and Expenses 4,218 4,986 15,214 14,264 Loss from Operations (4,218) (4,986) (15,214) (14,264) Other Expense: Exchange gain (loss) 6 (9) 7 (40)Interest income 382 170 1,127 197 Total Other Income (Expense) 388 161 1,134 157 Net Loss Before Income Taxes (3,830) (4,825) (14,080) (14,107)Income tax benefit 527 335 1,216 867 Net Loss Attributable to Theriva Biologics, Inc. and Subsidiaries $ (3,303) $ (4,490) $ (12,864) $ (13,240) Effect of Warrant exercise price adjustment — (340) — (340) Net Loss Attributable to Common Stockholders $ (3,303) $ (4,830) $ (12,864) $ (13,580) Net Loss Per Share - Basic and Diluted $(0.19) $(0.30) $(0.81) $(0.87) Weighted average number of shares outstanding during the period - Basic and Diluted 17,042,701 15,844,061 15,784,685 15,176,927 Net Loss (3,303) (4,490) (12,864) (13,240)Loss on foreign currency translation (702) (1,527) (379) (2,844)Total comprehensive loss $ (4,005) $ (6,017) $ (13,243) $ (16,084)