Synthetic Biologics Reports Second Quarter 2022 Operational Highlights and Financial Results -Prioritizing the advancement of novel oncolytic adenovirus (OV) platform- -Cash balance as of

Synthetic Biologics Reports Second Quarter 2022

Operational Highlights and Financial Results

-Prioritizing the advancement of novel oncolytic

adenovirus (OV) platform-

-Cash balance as of August 1, 2022 of $53.5

million, including the additional $3 million in gross proceeds from convertible preferred financing extends funding for business operations

-Conference call and webcast to be held today

MD, August 11, 2022 - Synthetic Biologics, Inc. (NYSE American: SYN), a diversified

clinical-stage company developing therapeutics designed to treat diseases in areas of high unmet need, today

reported financial results for the second quarter ended June 30, 2022, and provided a corporate update.

"We are pleased with the steady progress that continues to support

the advancement of our novel OV platform and further underscores the potential value of our lead candidate, VCN-01, designed to address

devastating cancers with high unmet need through a differentiated and potentially transformative mechanism of action," said Steven

A. Shallcross, Chief Executive Officer of Synthetic Biologics. "We have made the strategic decision to rationalize our spend and

prioritize our oncology program, which is expected to extend cash runway into the first quarter of 2024. We believe this sharpened approach

has the potential to drive near-term value for our shareholders and propel us forward to key milestones, including the initiation of our

Phase 2 study in patients with metastatic pancreatic adenocarcinoma in the fourth quarter of 2022 and our Phase 2/3 study in retinoblastoma

in the second half of 2023."

Recent Program Developments:

Anticipated Milestones:

Quarter Ended June 30, 2022 Financial Results

General and administrative expenses increased

to $1.5 million for the three months ended June 30, 2022, from $1.3 million for the three months ended June 30, 2021. This increase of

19% primarily comprised of increased consulting and legal costs related to the VCN acquisition, higher insurance costs, audit fees, and

public relations expenses and VCN administrative expenses not included in prior year. The charge related to stock-based compensation expense

was $86,000 for the three months ended June 30, 2022, compared to $83,000 the three months ended June 30, 2021.

Research and development expenses increased to

$3.5 million for the three months ended June 30, 2022, from approximately $1.9 million for the three months ended June 30, 2021. This

increase of 80% 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 expense for SYN-020, costs incurred related to our Phase 1a clinical trial of SYN-020 and expenses related to our

Phase 1b/2a clinical trial of SYN-004 (ribaxamase) in allogeneic HCT recipients. We anticipate research and development expense to increase

as we plan for and initiate enrollment for our phase 2 clinical trial for VCN-01 in PDAC, phase 2/3 clinical trial in retinoblastoma,

expand GMP manufacturing activities for VCN-01, and continue with supporting our VCN-11 and other preclinical and discovery initiatives.

The charge related to stock-based compensation expense was $27,000 for the three months ended June 30, 2022, compared to $19,000 related

to stock-based compensation expense for the three months ended June 30, 2021.

Other income was $17,000 for the three months

ended June 30, 2022 compared to other income of $2,000 for the three months ended June 30, 2021. Other income for the three months ended

June 30, 2022 is primarily comprised of interest income of $26,000 offset by an exchange loss of $9,000. Other income for the three months

ended June 30, 2021 is primarily comprised of interest income.

and cash equivalents totaled $52.3 million as of June 30, 2022, compared to $67.3 million as of December 31, 2021. Cash and cash

equivalents totaled approximately $53.5 million as of August 1, 2022.

July 29, the company closed a private placement of Series C and Series D convertible preferred stock with MSD Credit Opportunity

Master Fund, L.P. Total gross proceeds from the offerings, before deducting discounts, financial advisor

fees and other estimated offering expenses, were $3 million.

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

Investors may participate in the live call via telephone by dialing (800) 289-0571 (domestic) or (929) 477-0324 (international) and using

the conference ID: 7145566. 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.syntheticbiologics.com, under "Events" or by clicking here, for 90 days after the call.

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 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 initiation of VCN-01 dosing in an investigator sponsored study of

brain tumors at the University of Leeds (H2 2022), initiation of 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 Phase 2/3 study

of VCN-01 as an adjunct to chemotherapy in pediatric patients with advanced retinoblastoma (H2 2023), topline data read out from the first

cohort of the SYN-004 study in allo-HCT patients followed by initiation of the second cohort (H2 2022), the potential value of VCN-01,

designed to address devastating cancers with high unmet need through a differentiated and potentially transformative mechanism of action,

extending the cash runway into the first quarter of 2024 and the potential to drive near-term value for shareholders and propel Synthetic

Biologics forward to key milestones, including the initiation of a Phase 2 study in patients with metastatic pancreatic adenocarcinoma

in the fourth quarter of 2022 and a Phase 2/3 study in retinoblastoma in late 2023 and research and development expense increasing as

Synthetic Biologics plans for and initiates enrollment for its phase 2 clinical trial for VCN-01 in PDAC, phase 2/3 clinical trial in

retinoblastoma, expands GMP manufacturing activities for VCN-01, and continues with 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, Synthetic Biologics' ability to

reach clinical milestones when anticipated, Synthetic Biologics' ability to successfully combine and operate the business of Synthetic

Biologics and VCN, Synthetic Biologics' 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 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 current reports on Form 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:

LifeSci Advisors, LLC

Synthetic Biologics, Inc. and Subsidiaries

Condensed Consolidated Balance Sheets

(In thousands except share and par value amounts)