Synthetic Biologics Announces Presentation on VCN-11, a Novel Oncolytic Adenovirus Designed to Evade Neutralizing Antibodies at the Upcoming 25th Annual Meeting of the American Society of Gene & Cell Therapy (ASGCT)

– VCN-11 incorporates a proprietary albumin binding domain in the virus shell with the potential to improve systemic delivery and extend therapeutic efficacy through a multi-dosing strategy-

– Data to be featured in an oral presentation on Monday, May 16 at 5:15 p.m. ET-

ROCKVILLE, Md., May 04, 2022 (GLOBE NEWSWIRE) — Synthetic Biologics, Inc. (NYSE American: SYN), a diversified clinical-stage company developing therapeutics designed to treat diseases in areas of high unmet need, today announced an upcoming oral presentation on novel oncolytic adenovirus VCN-11 at the 25th Annual Meeting of the American Society of Gene & Cell Therapy (ASGCT), to be held virtually and in-person from May 16-19, 2022 in Washington, D.C.

The oral presentation will feature Ramon Alemany, Ph.D., Head of the Immunotherapy and Virotherapy Group at the Translational Research Laboratory of the Institut Catala d’Oncologia (ICO) and Institut de Investigacio Biomedica de Bellvitage (IDIBELL).

“We are excited to present new data on VCN-11, which should further position us at the forefront of oncolytic virus development,” said Steven A. Shallcross, Chief Executive Officer of Synthetic Biologics. “VCN-11 is a next-generation adenovirus that is genetically modified to express hyaluronidase and degrade the protective tumor stroma barrier. It is also engineered to incorporate a proprietary albumin binding domain in the virus’ outer shell, which is intended to improve systemic delivery by enabling the virus to coat itself in albumin and thereby evade neutralizing antibodies (NAbs). The presentation at ASGCT will include preclinical results showcasing the potential of VCN-11 to balance safety, with no major toxicities observed, and effectively target tumors after intravenous re-administration, even in the presence of high level NAbs. We look forward to building upon our foundation of compelling proof-of-mechanism data and continuing to advance our oncolytic adenovirus (OV) program through clinical development.”

The full abstract (#98) is accessible on the ASGCT conference portal and details for the oral presentation are included below.

Title: Oncolytic Adenovirus with Hyaluronidase Activity That Evades Neutralizing Antibodies and Allows Re-Administration: VCN-11
Session Title: Cancer-Oncolytic Viruses
Presenter: Ramon Alemany, Ph.D.
Presentation Date and Time: Monday, May 16, 2022, 5:15 – 5:30 p.m. ET

About Synthetic Biologics, Inc.

Synthetic Biologics, Inc. (NYSE American: SYN) is a diversified clinical-stage company developing therapeutics designed to treat diseases in areas of high unmet need. The Company recently consummated the acquisition of VCN Biosciences, S.L. (VCN), which is developing a new oncolytic adenovirus (OV) 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 (a) microbiome damage, (b) Clostridioides difficile infection (CDI), (c) overgrowth of pathogenic organisms, (d) the emergence of antimicrobial resistance (AMR), and (e) 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 Synthetic Biologics’ website at www.syntheticbiologics.com.

Forward-Looking Statements

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 new data on VCN-11 further positioning Synthetic Biologics at the forefront of oncolytic virus development, VCN-11 improving systemic delivery by incorporating a proprietary albumin binding domain in the virus’ outer shell, which also helps prevent inactivation by evading neutralizing antibodies (NAbs), the potential of VCN-11 to balance safety, with no major toxicities observed, and effectively target tumors after intravenous re-administration, even in the presence of high level Nab, and Synthetic Biologics building upon a foundation of compelling proof-of-mechanism data and continuing to advance its oncolytic adenovirus (OV) program through clinical development s. 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 to position Synthetic Biologics at the forefront of oncolytic virus development and continue to advance its oncolytic adenovirus (OV) program through clinical development, the ability of Synthetic Biologics’ and VCN’s product candidates to demonstrate safety and effectiveness, as well as results that are consistent with prior results, including VCN-11 having the ability to balance safety, with no major toxicities observed, and effectively target tumors after intravenous re-administration, even in the presence of high level Nabs; the ability to initiate clinical trials; 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 Synthetic Biologics’ 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 Synthetic Biologics’ and VCN’s products; developments by competitors that render such products obsolete or non-competitive; Synthetic Biologics’ and VCN’s ability to maintain license agreements;, the continued maintenance and growth of Synthetic Biologics’ and VCN’s patent estate; the ability to continue to remain well financed;, and other factors described in Synthetic Biologics’ 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 8-K. The information in this release is provided only as of the date of this release, and Synthetic 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