Theriva Biologics Reports Third Quarter 2022 Operational Highlights and Financial Results -Reported encouraging clinical data supporting the differentiated mode-of action of Theriva's novel oncolytic adenovirus (OV) plat

Reports Third Quarter 2022 Operational Highlights and Financial Results

-Reported encouraging

clinical data supporting the differentiated mode-of action of Theriva's novel oncolytic adenovirus (OV) platform-

from the Federal Drug Administration (FDA) and Spanish Competent Authority (AEMPS) for the planned Phase 2 clinical trial of systemically

administered VCN-01 in Pancreatic Ductal Adenocarcinoma (PDAC) patients-

safety and pharmacokinetic data from Cohort 1 of the Phase 1b/2a clinical trial of SYN-004 (ribaxamase) in allogeneic hematopoietic cell

transplant recipients and dosed the first patient in Cohort 2-

-As of September 30,

2022, Theriva Biologics reports $50.5 million in cash, which is expected to provide runway into the first quarter of 2024-

-Conference call and webcast to be held on

Friday, November 11 at 8:30 a.m. ET-

November 10, 2022 - 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 quarter ended September 30,

2022, and provided a corporate update.

by our clinical results demonstrating the therapeutic potential of Theriva's oncology-focused platform," said Steven A. Shallcross,

Chief Executive Officer of Theriva Biologics. "Important clinical data for VCN-01, our lead oncolytic virus product candidate was

presented at ESMO, further validating VCN-01's differentiated mechanism of action and potential to provide meaningful clinical

benefit across multiple solid tumor indications. With regulatory clearance from the FDA and Spanish Competent Authority (AEMPS), our

near-term priority is the initiation of Theriva's Phase 2 study of VCN-01 in combination with standard-of-care chemotherapy (gemcitabine/nab-paclitaxel)

as a first line therapy for patients with newly-diagnosed metastatic pancreatic ductal adenocarcinoma (PDAC). We will also seek to leverage

our Orphan Drug Designation and engage with regulatory agencies to define the best path forward for VCN-01 in the treatment of advanced

retinoblastoma. We look forward to providing updates on Theriva's progress as we deliver on upcoming milestones and drive shareholder

Highlights and Anticipated Milestones:

SYN-004 (ribaxamase):

September 30, 2022 Financial Results

General and administrative

General and administrative

expenses increased to $2.4 million for the three months ended September 30, 2022, from $1.3 million for the three months ended September 30,

2021. This increase of 88% was primarily comprised of increased consulting and legal costs related to the VCN acquisition, increase in

the fair value of the contingent consideration, higher insurance costs, audit fees, and public relations expenses, and VCN administrative

expenses not included in the prior year. The charge related to stock-based compensation expense was $93,000 for the three months ended

September 30, 2022, compared to $83,000 for the three months ended September 30, 2021.

Research and development

Research and development

expenses increased to $2.6 million for the three months ended September 30, 2022, from approximately $2.0 million for the three

months ended September 30, 2021. This increase of 30% is primarily the result of VCN research expenses related to VCN-01 not incurred

in the prior year and, to a lesser extent, higher manufacturing expenses related to our Phase 1a clinical trial of SYN-020. We anticipate

research and development expense to increase as we plan for and initiate enrollment for our VIRAGE phase 2 clinical trial for VCN-01

in PDAC and our proposed 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 $28,000 for the three

months ended September 30, 2022, compared to $19,000 related to stock-based compensation expense for the three months ended September 30,

Other income/Expense

$161,000 for the three months ended September 30, 2022 compared to other income of $2,000 for the three months ended September 30,

2021. 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. Other income for the three months ended September 30, 2021 was primarily comprised of interest income.

Cash and cash equivalents

totaled $50.5 million as of September 30, 2022, compared to $67.3 million as of December 31, 2021.

will host a conference call at 8:30 a.m. ET today to review the third quarter 2022 operational highlights and financial results.

Individuals may participate in the live call via telephone by dialing (888) 254-3590 (domestic) or (929) 477-0402 (international) and

using the conference ID: 5687287. 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 "Investors" section of the company's website,

https://www.therivabio.com, under "Events" or by clicking here, for 90 days after the call.

(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 VCN Biosciences, S.L. (VCN), 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 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

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 cash being expected to provide runway into the

first quarter of 2024, VCN-01 providing meaningful clinical benefit across multiple solid tumor indications, leveraging the Orphan Drug

Designation and engaging with regulatory agencies to define the best path forward for VCN-01 in the treatment of advanced retinoblastoma,

providing updates on Theriva's progress as Theriva delivers on upcoming milestones and driving shareholder value, VCN-01- as

a potential means of enabling the use of immunotherapeutic agents in patients

who are unresponsive to these cancer therapies, initiation of VCN-01 dosing in an investigator sponsored study of brain tumors at the

University of Leeds (Q4 2022), initiation of VIRAGE, a Phase 2 study of VCN-01 in combination with standard-of-care chemotherapy (gemcitabine/nab-paclitaxel)

as a first line therapy in newly diagnosed metastatic PDAC patients (Q4 2022), initiation of a clinical study evaluating

VCN-01 as an adjunct to chemotherapy in pediatric patients with advanced retinoblastoma (H2 2023) and

completing the second cohort of our Phase 1b/2a clinical study of SYN-004 for the prevention of acute graft-versus-host-disease in bone

marrow transplant patients in the first quarter 2024. 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 initiation of VCN-01

dosing in an investigator sponsored study of brain tumors at the University of Leeds (Q4 2022), initiation of VIRAGE, a Phase 2 study

of VCN-01 in combination with standard-of-care chemotherapy (gemcitabine/nab-paclitaxel) as a first line therapy in newly diagnosed metastatic

PDAC patients (Q4 2022), initiation of a clinical study evaluating VCN-01 as an adjunct to chemotherapy in pediatric patients with advanced

retinoblastoma (H2 2023), completing the second cohort of our Phase 1b/2a clinical study of SYN-004 for the prevention of acute graft-versus-host-disease

in bone marrow transplant patients in the first quarter 2024, the ability of VCN-01- as a potential

means of enabling the use of immunotherapeutic agents in patients who are unresponsive to these cancer therapies, 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 2024, and other factors

described in the Company's Annual Report on Form 10-K for the year ended December 31, 2021 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