TOVX 10-K & 10-Q changes, risk factors and insider trading

Our consolidated financial statements as of December 31, 20242025 have been prepared under the assumption that we will continue as a going concern for the next twelve months. In addition, our independent registered public accounting firm has issued a report that includes an explanatory paragraph referring to our recurring losses from operations (anticipated continued losses in the future) and net capital deficiency that raise substantial doubt in our ability to continue as a going concern without additional capital becoming available. Our ability to continue as a going concern is dependent upon our ability to obtain additional equity or debt financing, attain further operating efficiencies, reduce expenditures, and, ultimately, to generate revenue. Our consolidated financial statements as of December 31, 20242025 did not include any adjustments that might result from the outcome of this uncertainty. We expect that our current cash will be able to fund operations into the thirdfirst quarter of 20252027; buthowever, the current cash will notonly be sufficient to fundrun operationscertain forclinical twelvetrials monthsand no assurances can be provided and our cash could differ materially from theour dateexpectations based on various factors, many of thewhich filingare out of thisour Annual Report.control.

During the year ended December 31, 2024, our operating activities used net cash of approximately $16.9 million and as of December 31, 2024 our cash and cash equivalents were $11.6 million. With the exception of the three months ended December 31, 2017 and June 30, 2010, we have experienced significant losses since inception and have a significant accumulated deficit. As of December 31, 2024, our accumulated deficit totaled approximately $335.0 million on a consolidated basis. Pursuant to the VCN Purchase Agreement, we have agreed to use reasonable efforts to commercialize VCN-01 and we agreed as a post- closing covenant to commit to fund VCN's research and development programs, including but not limited to VCN-01 PDAC Phase 2 clinical trial, VCN-01 RB pivotal trial and necessary G&A within a budgetary plan of approximately $27.8 million. We expect to incur additional operating losses in the future and therefore expect our cumulative losses to increase. With the exception of the quarter ended June 30, 2010, and limited laboratory revenues from Adeona Clinical Laboratory, which we sold in March 2012, we have generated very minimal revenues. We do not expect to derive revenue from any source in the near future until we or our potential partners successfully commercialize our products. We expect our expenses to increase in connection with our anticipated activities, particularly as we continue research and development, initiate and conduct clinical trials, and seek marketing approval for our product candidates. Until such time as we receive approval from the FDA and other regulatory authorities for our product candidates, we will not be permitted to sell our products and therefore will not have product revenues from the sale of products. For the foreseeable future we will have to fund all of our operations and capital expenditures from equity and debt offerings, cash on hand, licensing and collaboration fees and grants, if any. We will need to raise additional capital to fund our operations and meet our current timelines and we cannot be certain that funding will be available on acceptable terms on a timely basis, or at all. The amount of government funding available for grants is dependent upon governmental budgets over which we have no control and which change with new administrations. Based on our current plans, we expect that our current cash will be ablesufficient to fund operations into the thirdfirst quarter of 2025 but will not be sufficient to fund our operations for the next twelve months2027 and will only be sufficient to cover overhead costs, close out of the VIRAGE Phase 2b clinical trial, commence and complete oura plannedpotential Phase 2a study evaluating VCN-01 dosing frequency, exploratory VCN-01 manufacturing scale-up activities, regulatory interactions regarding proposed VCN-01 clinical trials of VCN-01 (in PDAC and retinoblastoma),retinoblastoma, and preclinical studies supporting VCN-01 and VCN-12, the first candidate from our VCN-X discovery program. We believe our cash will also be sufficient to fund our committed obligations under the terms of the Purchase Agreement related to the Acquisition, but may not be sufficient for additional trials of VCN-01, SYN-020VCN-01 or SYN-004, or to complete the last cohort of the Phase 1a/2a clinical trial of SYN-004, which are expected to require significant cash expenditures. In addition, based on the significant anticipated cost of a Phase 3 clinical program in a broad indication for SYN-004, we expect it will not be feasible for us to initiate and complete this trial at this time without a partner given the capital constraints tied to our current market cap and share price. We intend to focus our capital on our VCN-01 clinical trials and do not intend to provide further funding for our development of SYN-004 internally but intend to out-license or partner further development of SYN-004. Further development of VCN’s product candidates will require additional funding. To the extent that we raise additional funds by issuing equity securities, our stockholders may experience significant dilution. Any debt financing, if available, may involve restrictive covenants that may impact our ability to conduct our business and also have a dilutive effect on our stockholders. A failure otherwise to secure additional funds when needed in the future whether through an equity or debt financing or a sufficient amount of capital without a strategic partnership could result in us being unable to complete planned preclinical and clinical trials or obtain approval of our product candidates from the FDA and other regulatory authorities. In addition, we could be forced to delay, discontinue or curtail product development, foregoforgo sales and marketing efforts, and foregoforgo licensing in attractive business opportunities.opportunities, cease operations, sell or otherwise liquidate our assets or reorganize the Company, or complete a combination of the foregoing. Our ability to raise capital through the sale of securities may be limited by the rules of the SEC and NYSE American LLC (“NYSE American”) that place limits on the number and dollar amount of securities that may be sold. There can be no assurances that we will be able to raise the funds needed, especially in light of the fact that our ability to sell securities registered on our registration statement on Form S-3 will be limited until such time the market value of our voting securities held by non-affiliates is $75 million or more. We also may be required to seek collaborators for our product candidates at an earlier stage than otherwise would be desirable and on terms that are less favorable than might otherwise be available.

We have a history of losses and we have incurred, and will continue to incur, substantial losses and negative operating cash flow. Even if we succeed in developing and commercializing one or more of our product candidates, we may still incur substantial losses for the foreseeable future and may not sustain profitability. We anticipate a need for additional employees as we undertake later stage clinical trials. We have also incurred certain obligations pursuant to the terms of the VCN Purchase Agreement including the assumption of $2.4 million of liabilities and have agreed to a post-closing covenant to commit to fund research and development of VCN-01 and OV pipeline programs, including but not limited to the VCN-01 PDAC Phase 2 trial, a VCN-01 RB pivotal trial and necessary G&A within a budgetary plan of approximately $27.8 million with $5.0 million remaining as of December 31, 2024.

We mayexpect to experience negative cash flow for the foreseeable future as we fund our development and clinical programs with capital expenditures. As a result, we will need to raise additional capital or generate significant revenues in order to achieve and maintain profitability. We may not be able to generate these revenues or achieve profitability in the future. Our failure to achieve or maintain profitability, which we do not anticipate will occur in the near future, could negatively impact the value of our commonCommon stockStock and underlying securities. There can be no assurance that funding will be available on acceptable terms on a timely basis, or at all. The various ways that we could raise capital carry potential risks. Any additional sources of financing will likely involve the issuance of our equity securities, which will have a dilutive effect on our stockholders. If we raise funds through collaborations and licensing arrangements, we might be required to relinquish significant rights to our technologies or tests or grant licenses on terms that are not favorable to us. The amount of government funding available for grants is dependent upon governmental budgets over which we have no control and which change with new administrations.

The actual amount of funds we will need to operate is subject to many risk factors, some of which are beyond our control.

The actual amount of funds we will need to operate is subject to many factors, some of which are beyond our control. These factors includeinclude, without limitation, the following:

We are a clinical-stage biopharmaceutical company that began to focus on development of oncolytic virusesOVs for treatment of various types of cancer in 2022. We have never generated any product revenue, do not expect to generate revenue in the near future and do not have any products approved for sale. Our operations to date have been primarily focused on developing our product candidates. We have not yet successfully obtained marketing approval, manufactured any product candidate at commercial scale, or conducted sales and marketing activities that will be necessary to successfully commercialize our product candidates. Consequently, predictions about our future success or viability may not be as accurate as they could be if we had a longer operating history or a history of successfully developing and commercializing product candidates.

WeAlthough we currently believe that our internal controls are effective, we have identified material weaknesses in our internal controls in the past, and we cannot provide assurances that additional material weaknesses will not occur in the future

If our internal control over financial reporting or our disclosure controls and procedures are not effective, we may not be able to accurately report our financial results, prevent fraud, or file our periodic reports in a timely manner, which may cause investors to lose confidence in our reported financial information and may lead to a decline in our stock price. Our management is responsible for establishing and maintaining adequate internal control over our financial reporting, as defined in Rule 13a- 15(f) under the Exchange Act. Based on our assessment, we have concluded that as of December 31, 2024 we have remediated2025 our priorinternal weaknesscontrol over internalfinancial controls.reporting Duringand our disclosure controls and procedures are effective. However, during 2023 and the first three quarters of 2024, we dididentified certain material weaknesses in our internal controls, which led to a determination that our controls were not maintain effective review controls at a sufficient level of precision with certain financial statement areas and over unusual transactions involving complex accounting and related disclosure requirements. We also did not maintain effective information technology general controls over user access, program change management, and segregation of duties, within certain key information systems supporting our accounting and financial reporting processes. Additionally, many of our business process controls dependent upon the information derived from these information systems were also ineffective, as we did not design and implement controls to validate the completeness and accuracy of underlying data utilized in the operation ofduring those controls.periods. While we have takentook remedial action to address the previously identified material weaknesses in 2024 and we now believe that our internal control over financial reporting ishave effective,been, and continue to be, effective since December 31, 2024, we cannot provide any assurance that such remedial measures, or any other remedial measures we take,take from time to time, will continue to be effective. If we fail to maintain effective internal control over financial reporting, we may not be able to accurately report our financial results, detect or prevent fraud, or file our periodic reports in a timely manner, which may, among other adverse consequences, cause investors to lose confidence in our reported financial information and lead to a decline in our stock price. In addition, a material weakness will not be considered remediated until the applicable controls operate for a sufficient period of time and management has concluded, through testing, that these controls are designed and operating effectively. Although management believes that the previously identified material weaknesses have beenwere remediated prior to December 31, 2024, there can be no assurance that our internal control over financial reporting, as modified, will enable us to identify or avoid material weaknesses in the future.

We expect to seek to raise additional capital in the future to help fund development of our proposed products. If we raise additional capital through the issuance of equity or of debt securities, the percentage ownership of our current stockholders will be reduced. We may also enter into strategic transactions, issue equity as consideration for acquisitions or part of license issue fees to our licensors, compensate consultants or settle outstanding payables using equity that may be dilutive. We are authorized to issue 350,000,000 shares of Common Stock, of which 2,782,44945,892,668 shares of Common Stock were outstanding as of March 4,10, 2025.2026. If all of the unissued authorized shares were issued stockholders ownership percentage will be significantly diluted.

Our quarterly and annual operating results may fluctuate significantly in the future, which makes it difficult for us to predict our future operating results. The VCN Purchase Agreement entered into in connection with the Acquisition requires that we make certain cash payments to Grifols upon attainment of certain milestones, which payments may vary significantly from period to period and any such variance could cause a significant fluctuation in our operating results from one period to the next. As discussed elsewhere in this Annual Report, the payment of $5.0 million of contingent consideration earned by Grifols pursuant to the Acquisition has been deferred pending ongoing discussions with Grifols. From time to time, we may enter into collaboration agreements with other companies that include development funding and significant upfront and milestone payments and/or royalties, which may become an important source of our revenue. Accordingly, our revenue may depend on development funding and the achievement of development and clinical milestones under any potential future collaboration and license agreements and sales of our products, if approved. These upfront and milestone payments may vary significantly from period to period and any such variance could cause a significant fluctuation in our operating results from one period to the next. In addition, our manufacturing and clinical trial expenses, which are anticipated to be significant, may fluctuate significantly quarter to quarter based upon whether or not we are engaged in clinical trials or manufacturing our product candidates, and timing of our process development work. Furthermore, we measure compensation cost for stock-based awards made to employees at the grant date of the award, based on the fair value of the award as determined by ourthe boardBoard of directors,Directors, and recognize the cost as an expense over the employee'semployee’s requisite service period. As the variables that we use as a basis for valuing these awards change over time, our underlying stock price and stock price volatility, the magnitude of the expense that we must recognize may vary significantly. Furthermore, our operating results may fluctuate due to a variety of other factors, many of which are outside of our control and may be difficult to predict, including the following:

Prior to the VCN Acquisition, our focus was on the microbiome and our research and development was focused primarily on therapeutics for various microbiome related diseases. Upon the VCN Acquisition, our focus has shifted to the use of oncolytic virusesOVs to treat cancer. Although,Although members of our management and scientific/development teams have experience in the research and development of cancer treatments, we may not be successful as a company with such focus.

In the past Oncolytic VirusesOVs have experienced certain safety and efficacy challenges.

Although current clinical trials of OVs have supported their role as a potential treatment for cancer, there is the risk of virus-related toxicities in vivo and possible transmission to patients'patients’ contacts, such as other patients and health care workers. In recent years, clinical trials to address these concerns have been conducted. Any such transmission by VCN-01 (zabilugene almadenorepvec) or a competitor would have an adverse impact on our future OV research and development efforts. Likewise, a number of OVs have previously failed to meet their primary endpoints in advanced clinical trials, potentially reducing investor and partner interest or confidence in the development of new such therapies, however well differentiated they are from previous products.

The success of our business currently depends on our development, approval and commercialization of our lead product candidate, VCN-01.VCN-01 (zabilugene almadenorepvec). Our ongoing Phase 1b/2a clinical trial of SYN-004 for the prevention of aGVHD in allogeneic HCT recipients, our completed Phase 1 single ascending and multiple ascending dose studies of SYN-020 and ongoing early-stage clinical trials of VCN-01 are not designed as registrational clinical trials and we currently do not have the necessary funding to complete any late stage registrational clinical trials. There are many uncertainties known and unknown that may affect the outcome of future clinical trials. All of our product candidates, including VCN-01, SYN-004 (ribaxamase), and SYN-020 will require additional clinical and non-clinical development, regulatory review and approval in multiple jurisdictions, substantial investment, access to sufficient commercial manufacturing capacity and significant marketing efforts before we can generate any revenue from product sales. Although Rasayana has assumed all responsibility and costs for the development and commercialization of SYN-020, and has committed to use reasonable commercial efforts to develop and commercialize SYN-020 and to meet certain development milestones set forth in the Rasayana License Agreement, no assurances can be made that they will be successful in further developing or obtaining regulatory approval of products related thereto or that we will receive any development milestone payments or sales milestone payments from Rasayana in connection therewith. Regardless of whether our clinical trials (or, in the case of SYN-020, Rasayana’s clinical trials) are deemed to be successful, promising new product candidates may fail to reach the market or may only have limited commercial success because of efficacy or safety concerns, failure to achieve positive clinical outcomes, inability to obtain necessary regulatory approvals or satisfy regulatory criteria, limited scope of approved uses, excessive costs to manufacture, the failure to establish or maintain intellectual property rights, or infringement of the intellectual property rights of others. Failure to obtain regulatory approvals of VCN-01, SYN-004 (ribaxamase) or SYN-020 in a timely manner would have a material adverse impact on our business. Even if we successfully develop VCN-01, SYN-004 (ribaxamase), SYN-020 or other new products or enhancements, or if Rasayana successfully develops SYN-020 or new products or enhancements covered by the Rasayana License Agreement, they may be quickly rendered obsolete by changing customer preferences, changing industry standards, or competitors’ innovations. Innovations may not be quickly accepted in the marketplace because of, among other things, entrenched patterns of clinical practice or uncertainty over third-party reimbursement. We cannot state with certainty when or whether any of our products under development will be launched, whether we will be able to develop, license, or otherwise acquire drug candidates or products, or whether any products will be commercially successful. Failure to launch successful new products or new indications for existing products may cause our products to become obsolete, which may limit our ability to achieve profitability.

We have in the past, and may continue to seek to, form or seek strategic alliances or enter into additional licensing arrangements in the future, and we may not realize the benefits of such alliances or licensing arrangements.

As discussed elsewhere in this Annual Report on Form 10-K, on February 17, 2026, we entered into the Rasayana License Agreement with Rasayana, pursuant to which we granted Rasayana an exclusive worldwide license with the right to grant sublicenses to research, develop, manufacture and commercialize any Product (as such term is defined in the Rasayana License Agreement), which includes SYN-020, comprising, containing, or covered by the Licensed IP (as such term is defined in the Rasayana License Agreement) and/or devised, developed, or produced using the Licensed IP. We are also considering licensing and partnership opportunities for the further development of our SYN-004 (ribaxamase) product candidate, and may consider other strategic opportunities for this product candidate or our other product candidates from time to time. We may form or seek strategic alliances, create joint ventures or collaborations or enter into additional licensing arrangements with third parties that we believe will complement or augment our development and commercialization efforts with respect to our product candidates and any future product candidates that we may develop. Any of these relationships may require us to incur non-recurring and other charges, increase our near and long-term expenditures, issue securities that dilute our existing stockholders or disrupt our management and business. In addition, we face significant competition in seeking appropriate strategic partners and the negotiation process is time-consuming and complex. Moreover, we may not be successful in our efforts to establish a strategic partnership or other alternative arrangements for our product candidates because they may be deemed to be at too early a stage of development for collaborative effort and third parties may not view our product candidates as having the requisite potential to demonstrate safety and efficacy. If we license products or businesses, we may not be able to realize the benefit of such transactions if we are unable to successfully integrate them with our existing operations and company culture. We cannot be certain that, following a strategic transaction or license, we will achieve the revenue or specific net income that justifies such transaction. Any delays in entering into new strategic partnership agreements related to our product candidates could delay the development and commercialization of our product candidates in certain geographies for certain indications, which would harm our business prospects, financial condition and results of operations.

In addition to our own patent applications, we also currently rely on licensing agreements with third party patent holders/licensors for our products. We have entered into license agreements upon which our OV technology is dependent. If we breach the terms of any of our license agreements or collaborations, including any failure to make royalty payments required thereunder or failure to reach certain developmental milestones or fulfill our obligations under the agreements could result in a termination of the agreements. The Technology Transfer Agreement”) between VCN and IDIBELL for the exclusive license of the right to use a Spanish patent number P200901201 titled “Oncolytic adenoviruses for treating cancer” provides IDIBELL with the right to revoke the license if VCN ceases business activities for a continuous year or ceases to utilize the technology subject of the Technology Transfer Agreement, uses the technology in violation of the principals of IDIBELL or ICO or stops maintaining the patent licensed under the Technology Transfer Agreement. The ICO License provides that VCN and its sublicensees have an obligation to use all diligent and commercially reasonable efforts for the exploitation of the patent, otherwise, ICO may proceed to recover the license. The “IDIBELL/ICO License Agreement provides that the licensors have the right to revoke the IDIBELL/ICO License Agreement if VCN during a continuous period of two years abandons its research or development activities of the licensed patent or activities aimed at exploitation of the resulting products. If any license were to terminate and we were to lose the right to commercialize our products, our business opportunity would be adversely affected. Furthermore, we currently have very limited product development capabilities, and limited marketing or sales capabilities. For us to research, develop, and test our product candidates, we would need to contract with outside researchers, in most cases those parties that did the original research and from whom we have licensed the technologies.

VCN’s collaboration agreements require that Theriva Biologics S.L. engage in certain research and development activities that require additional expenditures. Our agreement with Washington University may require that we initiate certain studies and file or have accepted an NDA within a certain amount of time, each of which are costly and will require additional expenditures. Although all manufacturing, preclinical studies and human clinical trials are expensive and difficult to design and implement, costs associated with the manufacturing, research and development of biologic product candidates are generally greater in comparison to small molecule product candidates. Due to our small work force, we expect in future years to require additional personnel to support our later stage research and development efforts. Manufacturing of VCN-01,VCN-01 (zabilugene almadenorepvec) and SYN-004 (ribaxamase) and SYN-020 to support potential future clinical studies will require us to incur additional expenses.

The pharmaceutical and biotechnology industries, including the oncolytic virusOV industry and the monoclonal antibody industry, are characterized by rapidly evolving technology and intense competition. Our competitors include major multi-national pharmaceutical companies and biotechnology companies developing both generic and proprietary therapies to treat serious diseases. Many of our competitors have drugs that have already been commercialized and therefore benefit from being first to market their products. Many of these companies are well-established and possess technical, human, research and development, financial, and sales and marketing resources significantly greater than ours. In addition, many of our potential competitors have formed strategic collaborations, partnerships and other types of joint ventures with larger, well established industry competitors that afford these companies’ potential research and development and commercialization advantages in the therapeutic areas we are currently pursuing. Academic research centers, governmental agencies and other public and private research organizations are also conducting and financing research activities which may produce products directly competitive to those being developed by us. In addition, many of these competitors may be able to obtain patent protection, obtain FDA and other regulatory approvals and begin commercial sales of their products before us, including for different indications of the same active ingredients that comprise our pipeline products. These competitors will compete with us in product sales as well as recruitment and retention of qualified scientific and management personnel, establishment of clinical trial sites and patient enrollment for clinical trials, as well as in the acquisition of technologies and technology licenses complementary to our programs or advantageous to our business. Companies pursuing clinical development of modified oncolytic adenoviruses include AdCure Bio LLC, Calidi Biotherapeutics, Inc., Candel Therapeutics, Inc., CG Oncology, Inc., Elicera Therapeutics AB, EpicentRx, Inc., GeneMedicine, Co Ltd., IconOVir Bio, Inc., Lokon Pharma AB, Memgen, Inc., Multivir, Inc., NewGenPharm Incorporation, Oncolys BioPharma, Inc., Orca Therapeutics B.V., Akamis Bio Ltd. (formerly PsiOxus Therapeutics Ltd), Shanghai Sunway Biotech Co., Ltd, Circio Holding ASA (formerly Targovax Oy|Targovax ASA), Tessa Therapeutics, Theolytics Ltd., TILT Biotherapeutics, Ltd., Urogen Pharma, and Valo Therapeutics Oy. OV products have been or are being developed using other virus backbones, including: arenavirus (Hookipa Pharma, Inc.); Coxsackie virus (Viralytics Ltd., Oncorus Inc.); herpes simplex virus (Amgen, Inc., Candel Therapeutics, Inc., Daiichi Sankyo Company Ltd., Replimune, Inc., Takara Bio, Inc., Treovir LLC, Virogin Biotech, Inc., Wuhan Binhui Biotechnology Co., Ltd.); Maraba virus (Turnstone Biologics, Inc.); measles virus (Themis Biosciences GmbH, Vyriad, Inc.); myxoma virus (OncoMyx Therapeutics, Inc.); parvovirus (Oryx GmbH & Co. KG), reovirus (Oncolytics Biotech, Inc.); Seneca Valley virus (Seneca Therapeutics Inc., Oncorus Inc.); vesicular stomatitis virus (Boehringer Ingelheim, Cytonus Therapeutics, Inc., Vyriad, Inc.); and vaccinia viruses (Genelux Corporation, Imugene Ltd, Joint Biosciences Ltd, KaliVir Immunotherapeutics LLC, SillaJen, Inc., Transgene SA, Turnstone Biologics, Corp.). In addition, academic research centers may develop technologies that compete with our VCN-01,VCN-01 (zabilugene almadenorepvec), SYN-004 (ribaxamase) and SYN-020,SYN-020 products and our other technologies. Should clinicians or regulatory authorities view alternative therapeutic regiments as more effective than our products, this might delay or prevent us from obtaining regulatory approval for our products, or it might prevent us from obtaining favorable reimbursement rates from payers, such as Medicare, Medicaid, hospitals and private insurers.

If the parties we depend on for supplying substance raw materials for our product candidates and certain manufacturing-related services do not timely supply these products and services in sufficient quality or quantity, or if current drug supply becomes unusable,itunusable, it may delay or impair our ability to develop, manufacture and market our product candidates.

We rely on suppliers for the substance raw materials of our product candidates and third parties for manufacturing-related services to produce material that meets appropriate content, quality and stability standards and use in clinical trials of our products and, after approval, for commercial distribution. To succeed, clinical trials require adequate supplies of study material, which may be difficult or uneconomical to procure or manufacture and there can be no assurance that we will successfully procure such study material when needed, if at all, or even if procured, that we can do so in quantities and in a timely manner to allow our clinical trials to proceed as planned. Drug supply, once produced, is stored at clinical trial sites and vendor depots and we rely on these locations to maintain and protect the drug supply appropriately. Moreover, clinical drug supply has a finite shelf-life that may not be fully established prior to initiating early-stage clinical trials. We and our suppliers and vendors may not be able to (i) produce our study material to appropriate standards for use in clinical studies, (ii) perform under any definitive manufacturing, supply or service agreements with us, or (iii) remain in business for a sufficient time to successfully produce and market our product candidates, or (iv) prevent the drug supply from becoming unusable due to damage, loss or shelf-life expiration. If we do not maintain important manufacturing and service relationships, we may fail to find a replacement supplier or required vendor or manufacturer which could delay or impair our ability to conduct clinical trials and obtain regulatory approval for our products and substantially increase our costs or deplete profit margins, if any. If we do find replacement manufacturers and vendors, we may not be able to enter into agreements with them on terms and conditions favorable to us and there could be a substantial delay before a new facility could be qualified and registered with the FDA and foreign regulatory authorities.

The third-party manufacturers of the active pharmaceutical ingredient (API) and drug product for our lead product candidates, VCN-01,VCN-01 (zabilugene almadenorepvec), and SYN-004 (ribaxamase) and SYN-020,, are established cGMP manufacturers. For all other therapeutic areas, we have not yet established cGMP manufacturers for our biologic and drug candidates. We have used only one API manufacturer for each of our product candidates (VCN-01, SYN-004 orand SYN-020) (prior to entering into the Rasayana License Agreement) used in clinical trials to date. Although we believe additional manufacturers are available, if any of our manufacturers were to limit or terminate production or otherwise fail to meet the quality or delivery requirements needed to satisfy the supply commitments, the process of locating and qualifying alternate sources could require up to several months, during which time our production could be delayed. Any curtailment in the availability of our product candidates could have a material adverse effect on our business, financial position and results of operations. In addition, because regulatory authorities must generally approve raw material sources for pharmaceutical products, changes in raw material suppliers may result in production delays or higher raw material costs.

For our Phase 2 clinical trialtrials of VCN-01 in(zabilugene patients with PDAC,almadenorepvec), we arehave administeringor will administer our clinical product candidate, VCN-01, in combination with other approved standard of carecancer drugs. Any problems obtaining thethese standard of careco-administered drugs could result in a delay or interruption in our clinical trials.

For our ongoingproposed Phase 2pivotal clinical trial of VCN-01 in patients with PDAC, we areplan administeringto administer VCN-01 in combination with the already approved standard of care drugs, gemcitabine/nab-paclitaxel, for which there hashave recentlypreviously been a supply shortage.shortages. Therefore,A ourpotential clinical trial in refractory retinoblastoma is expected to administer VCN-01 in combination with topotecan. Our success will be dependent upon the continued use of and ability to obtain the standard of careco-administered drugs. We expect that in any other clinical trials we conduct for additional indications, our clinical product candidate will also be administered in combination with drugs owned by third parties. If any of the standard of care or third-partyco-administered drugs that are used in our clinical trials are unavailable while the trials are continuing, the timeliness and commercialization costs could be impacted. In addition, if any of these other drugs are determined to have safety or efficacy problems, our clinical trials and commercialization efforts would be adversely affected.

We have limited resources dedicated to designing, conducting and managing our preclinical studies and clinical trials. We rely on, third parties, including clinical research organizations (CROs),CROs, consultants and principal investigators, to assist us in designing, managing, conducting, monitoring and analyzing the data from our preclinical studies and clinical trials. We rely on these vendors and individuals to perform many facets of the clinical development process on our behalf, including conducting preclinical studies, the recruitment of sites and subjects for participation in our clinical trials, maintenance of good relations with the clinical sites, and ensuring that these sites are conducting our trials in compliance with the trial protocol and applicable regulations. If these third parties fail to perform satisfactorily, or do not adequately fulfill their obligations under the terms of our agreements with them, we may not be able to enter into alternative arrangements without undue delay or additional expenditures, and therefore the preclinical studies and clinical trials of our clinical product candidates may be delayed or prove unsuccessful.

As of March 6,12, 2025,2026, we employed 2015 full-time employees and 21 part-time employees, including employees located at Theriva Biologics’ offices in Barcelona, Spain. We have also engaged clinical consultants to advise us on our clinical programs and regulatory consultants to advise us on our dealings with the FDA and other foreign regulatory authorities. Due to our small work force, we expect in future years to require additional personnel to support our later stage research and development efforts. We have been and may be required to retain additional consultants and employees in order to fulfill our obligations under our licenses and collaborations for our development of VCN-01,VCN-01 (zabilugene almadenorepvec), SYN-004 (ribaxamase), SYN-020, and our agreements with Washington University and other collaborators. Our future performance will depend in part on our ability to successfully integrate newly hired officers into our management team and our ability to develop an effective working relationship among senior management.

Our business and the business of the suppliers of our clinical product candidates has been and is expected to continue to bewere materially and adversely affected by the pandemic and post-pandemic workforce and supply-chain issues. While we are currently not experiencing material delays, such events could result in the delay or complete or partial closure of clinical trial sites or one or more manufacturing facilities which could impact our supply of our clinical product candidates. In addition, it could impact economies and financial markets, resulting in an economic downturn that could impact our ability to raise capital or slow down potential partnering relationships.

The extent to which a pandemic may impact our business and clinical trials will depend on future developments, which are highly uncertain and cannot be predicted with confidence, such as the ultimate geographic spread of the disease, the duration of the outbreak, travel restrictions and social distancing in the United States and Spain, business closures or business disruptions and the effectiveness of actions taken in the United States, Spain, and other countries to contain and treat the disease. We do not yet know the full extent of potential delays or impacts on our business, operations, or the global economy as a whole. While the original spread of COVID-19 has been mitigated, the continued emergence of novel virus strains mean there is no guarantee that a future outbreak of this or any other widespread epidemics will not occur, or that the global economy will recover, either of which could seriously harm our business.

In addition, the global macroeconomic environment could be negatively affected by, among other things, pandemics or epidemics, instability in global economic markets, instability in the global credit markets, supply chain weaknesses, instability in the geopolitical environment as a result of the withdrawal of the United Kingdom from the European Union, the Russian war with Ukraine, the war in the Middle EastEast, military or other action taken by the United States in foreign countries and other political tensions, and foreign governmental debt concerns. Such challenges have caused, and may continue to cause, uncertainty and instability in local economies and in global financial markets.

ChangesTariffs, inreciprocal U.S.tariffs, economic sanctions, embargoes, import or internationalexport social,licensing political, regulatory and economic conditions or in laws and policies governing trade, manufacturing, development and investment in the countries where we currently sell our products or conduct our business, could adversely affect our business, reputation, financial condition and results of operations. Changes or proposed changes in U.S. or other countries’ trade policies may result in restrictions and economic disincentives on international trade. Tariffs, economic sanctionsrequirements and other changes in U.S. trade policy have in the past and could in the future trigger additional retaliatory actions by affected countries, and certain foreign governments have instituted or are considering imposing retaliatory measures on certain U.S. goods.countries. Further, any emerging protectionist or nationalist trends (whether regulatory-regulatory, or consumer-driven) either in the United States or in other countries could affect the trade environment. We,Our business, like many other multinational corporations, conduct a significant amount of business that would be impacted by changes to the trade policies of the United States and foreign countries (including governmental action related to tariffs, international trade agreements, or economic sanctions). Such changes have the potential to adversely impact the U.S. economy or certain sectors thereof or the economy of another country in which we conduct operations, our industry andthereof, the global demandeconomy, forand our products,industry, and as a result, could have a material adverse effect on our business, financial condition and results of operations.

To date, long-term safety and efficacy have not yet been demonstrated in clinical trials for any of our product candidates. Favorable results in our early studies or trials may not be repeated in later studies or trials as was the case with SYN-010. Even if our clinical trials are initiated and completed as planned, we cannot be certain that the results will support our product candidate claims. Success in preclinical testing and early clinical trials does not ensure that later clinical trials will be successful. Success in Phase 1 and Phase 2 studies of VCN-01 (zabilugene almadenorepvec) in PDAC or retinoblastoma does not ensure success of VCN-01, especially in light of the small number of patients treated in those trials. Success of our predecessor P1A clinical product or positive topline data from our previous SYN-004 (ribaxamase) Phase 1 and Phase 2 clinical trials, does not ensure success of SYN-004 (ribaxamase). Furthermore, the FDA could determine that VCN-01 (zabilugene almadenorepvec) or SYN-004 (ribaxamase) have not demonstrated appropriate safety and thus require additional clinical trials and safety data, despite prior positive clinical trial results. We cannot be sure that the results of later clinical trials would replicate the results of prior clinical trials and preclinical testing nor that they would satisfy the requirements of the FDA or other regulatory agencies. Clinical trials may fail to demonstrate that our product candidates are safe for humans and effective for indicated uses. A number of companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or unacceptable safety issues, notwithstanding promising results in earlier trials. Most product candidates that commence clinical trials are never approved as products. Any such failure could cause us or our sublicensee to abandon a product candidate and might delay development of other product candidates. Preclinical and clinical results are frequently susceptible to varying interpretations that may delay, limit or prevent regulatory approvals or commercialization. Any delay in, or termination of, our clinical trials would delay our obtaining FDA approval for the affected product candidate and, ultimately, our ability to commercialize that product candidate.

Our clinical trials may be suspended at any time for a number of reasons. We may voluntarily suspend or terminate our clinical trials if at any time we believe that they present an unacceptable risk to the clinical trial subjects. In addition, the FDA or other regulatory agencies may order the temporary or permanent discontinuation of our clinical trials at any time if they believe that the clinical trials are not being conducted in accordance with applicable regulatory requirements or that they present an unacceptable safety risk to the clinical trial subjects. For example, the FDA or foreign equivalents could determine that VCN-01 (zabilugene almadenorepvec) or SYN-004 (ribaxamase) has not demonstrated appropriate safety, that adverse events are drug related and require additional clinical trials and safety data, despite positive results from Phase 1 and Phase 2 clinical trials of VCN-01 or our SYN-004 Phase 2b clinical trial.

Regulatory authorities in some jurisdictions, including the United States and Europe, may designate drugs for the treatment or prevention of rare diseases or conditions with relatively small patient populations as orphan drugs. Under the Orphan Drug Act of 1983, the (“Orphan Drug Act”), the FDA may designate a product as an orphan drug if it is a drug intended to treat a rare disease or condition, which is defined as a patient population of fewer than 200,000 individuals in the United States. We have received orphan drug designation from both the FDA and EMA for VCN-01 (zabilugene almadenorepvec) for the treatment of retinoblastoma and for the treatment of pancreatic cancer. If a product with an orphan drug designation subsequently receives the first marketing approval for the indication for which it has such designation, the product is entitled to a seven-year period of marketing exclusivity in the United States, which precludes the FDA from approving another marketing application for the same drug for the same indication during that time period with some exceptions. A similar provision in the European Union allows 10 years of exclusivity in Europe. The European exclusivity period can be reduced to six years if a drug no longer meets the criteria for orphan drug designation or if the drug is sufficiently profitable so that marketing exclusivity is no longer justified. Orphan drug exclusivity may be lost in Europe under certain situations, such as the inability of the holder of the orphan drug designation to produce sufficient quantities of the drug to meet the needs of patients with the rare disease or condition or for certain other reasons.

In May 2024, the FDA granted Fast Track designation to VCN-01 (zabilugene almadenorepvec) for the treatment of pancreatic cancer. However, the receipt of such a designation for a product candidate may not result in a faster development process, review or approval compared to drugs considered for approval under conventional regulatory procedures and does not assure that the product will ultimately be approved by the regulatory authority or that approval will be granted within any particular timeframe. As a result, while we have received Fast Track designation for VCN-01 for the treatment of pancreatic cancer, we may not experience a faster development process, review or approval compared to conventional FDA procedures. In addition, the FDA may withdraw Fast Track designation if it believes that the designation is no longer supported by data from our clinical development program. Fast Track designation alone does not guarantee qualification for the FDA’s priority review procedures.

Although we have obtained rare pediatric disease designation for VCN-01 (zabilugene almadenorepvec) for the treatment of retinoblastoma, we may not be eligible to receive a priority review voucher in the event the FDA determines we no longer meet the criteria for designation, revokes the designation or FDA approval of a BLA for VCN-01 for retinoblastoma does not occur prior to September 30, 2026.2029.

The FDA grants rare pediatric disease designation for rare diseases (fewer than 200,000 affected persons in the United States) that are serious and life-threatening and primarily affect children ages 18 years or younger. The sponsor of an application for a rare pediatric disease drug product may be eligible for a voucher that can be used or sold to obtain a priority review for a subsequent application submitted under section 505(b)(1) of the FDCA or section 351 of the PHS Act. TheLegislative authorization for the rare pediatric disease priority review voucher (PRV) program was most recently reauthorizedauthorized by Congress through December 20, 2024, with the potential for priority review vouchers to be granted through September 30, 2026. We received rare pediatric disease designation from the FDA for VCN-01 on July 30, 2024. Vouchers for rare pediatric disease drugs are awarded for qualifying applications when the drug receives approval.2029.

We received rare pediatric disease designation from the FDA for VCN-01 (zabilugene almadenorepvec) on July 30, 2024. Vouchers for rare pediatric disease drugs are awarded for qualifying applications when the drug receives approval. Although VCN-01 has received rare pediatric disease designation for the treatment of retinoblastoma, VCN-01 may not receive a priority review voucherPRV for a number of reasons: VCN-01 may not receive approval for retinoblastoma prior to Septemberthe 30,required 2026deadline; VCN-01 may receive approval in adults, but not pediatric patients; VCN-01 may not meet the eligibility requirements for a priority voucher at the time we seek approval for VCN-01. Finally, a rare pediatric disease designation does not necessarily lead to faster development or regulatory review of the product or increase the likelihood that it will receive marketing approval. The failure to maintain rare pediatric disease designation for VCN-01 or if FDA approval does not occur prior to Septemberthe 30,required 2026deadline could result in the inability to receive a priority review voucher which could adversely affect our business, financial condition and results of operations.

We have in the past, and expect to have in the future, agreements with third-party contract research organizations (CROs) under which we have delegated to the CROs the responsibility to coordinate and monitor the conduct of our VCN-01,VCN-01 (zabilugene almadenorepvec), SYN-004 (ribaxamase) and SYN-020 (prior to entering into the Rasayana License Agreement) clinical trials and to manage data for our clinical programs. We also rely upon CROs to monitor and manage data for our clinical programs, as well as the execution of future nonclinical studies. We expect to control only certain aspects of our CROs’ activities. Nevertheless, we will be responsible for ensuring that each of our studies is conducted in accordance with the applicable protocol, legal, regulatory and scientific standards and our reliance on the CROs does not relieve us of our regulatory responsibilities.

In recent years, officials have made numerous proposals to change the health care system in the United States. These proposals include measures that would limit or prohibit payments for certain medical treatments or subject the pricing of drugs to government control. These proposed legislative and/or regulatory changes may negatively impact the reimbursement for our products, following approval. The availability of numerous generic treatments may also substantially reduce the likelihood of reimbursement for our future products. In addition, in many foreign countries, particularly the countries of the European Union, the pricing of prescription drugs is subject to government control. If our products are or become subject to government regulation that limits or prohibits payment for our products, or that subjects the price of our products to governmental control, we may not be able to generate revenue, attain profitability or commercialize our products.

As a result of legislative proposals and the trend towards managed health care in the United States, third-party payors are increasingly attempting to contain health care costs by limiting both coverage and the level of reimbursement of new drugs. They may also impose strict prior authorization requirements and/or refuse to provide any coverage of uses of approved products for medical indications other than those for which the FDA or foreign equivalent has granted market approvals. As a result, significant uncertainty exists as to whether and how much third-party payors will reimburse patients for their use of newly-approved drugs, which in turn will put pressure on the pricing of drugs. The downward pressure on healthcare costs in general, and prescription drugs in particular, has and is expected to continue to increase in the future.

The U.S. government and other governments have shown significant interest in pursuing continued healthcare reform. Any government-adopted reform measures could adversely impact the pricing of healthcare products and services in the United States or internationally and the amount of reimbursement available from governmental agencies or other third-party payors. Changes in applicable laws, rules, and regulations or the interpretation of existing laws, rules, and regulations could impact our business in the future by requiring, for example: (i) changes to our manufacturing arrangements; (ii) additions or modifications to product labeling; (iii) the recall or discontinuation of our products; or (iv) additional record-keeping requirements. If any such changes were to be imposed, they could adversely affect the operation of its business. The continuing efforts of the U.S. and foreign governments, insurance companies, managed care organizations and other payors of health care services to contain or reduce health care costs may adversely affect our ability to set prices for our products which we believe are fair, and our ability to generate revenues and achieve and maintain profitability.

We are a diversified clinical - stageclinical-stage company developing therapeutics designed to treat cancer and related diseases in areas of high unmet need. As a result of the acquisitionAcquisition in March 2022 of Theriva Biologics, S.L. ("VCN", formerly named VCN Biosciences, S.L.), described in more detail below (the "Acquisition"),2022, we began transitioningtransitioned our strategic focus to oncology, which is now our primary focus,oncology through the development of VCN'sVCN’s new oncolytic adenovirus platform designed for intravenous and intravitreal delivery to trigger tumor cell death, to improve access of co - administeredco-administered cancer therapies to the tumor, and to promote a robust and sustained anti - tumoranti-tumor response by the patient'spatient’s immune system. Our lead product candidate, VCNVCN-01 -(zabilugene 01,almadenorepvec), is a clinical stage oncolytic human adenovirus that is modified for tumor - selectivetumor-selective replication and to express an enzyme, PH20 hyaluronidase,hyaluronidase. isVCN-01 currentlyhas beingbeen evaluated in a Phase 22b clinical study for the treatment of pancreatic cancer ("“VIRAGE"”), and has recently been used to treat patients in a Phase 1 clinical study for the treatment of retinoblastoma, andas well as various other Phase 1 clinical studies for the treatment of other solid tumors including head and neck squamous cell carcinoma.

Prior to the Acquisition, our focus was on developing therapeutics designed to treat gastrointestinal (GI) diseases which included our clinical development candidates: (1) SYN-004 (ribaxamase) which is designed to degrade certain commonly used intravenous (IV) beta-lactam antibiotics within the GI tract to prevent microbiome damage, thereby preventing overgrowth and infection by pathogenic organisms such as Clostridioides difficile infection (CDI) and vancomycin resistant Enterococci (VRE), and reducing the incidence and severity of acute graft-versus-host-disease (aGVHD) in allogeneic hematopoietic cell transplant (HCT) recipients, and (2) 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. AsIn partFebruary 2026, we entered into the Rasayana License Agreement with Rasayana, pursuant to which we granted Rasayana an exclusive worldwide license with the right to grant sublicenses to research, develop, manufacture and commercialize any Product (as such term is defined in the Rasayana License Agreement), which includes SYN-020, comprising, containing, or covered by the Licensed IP (as such term is defined in the Rasayana License Agreement) and/or devised, developed, or produced using the Licensed IP. Pursuant to the terms of the Rasayana License Agreement, Rasayana will assume all responsibility and costs for the Development and Commercialization of the Products. We believe that this arrangement will provide us with potential to derive value from our SYN-020 asset, without the need for us to continue to invest additional working capital into the further development of the product candidate, thereby allowing us to focus our efforts and expenditures on the development of our strategic transformation into an oncology focused company, we are exploring value creation options for our SYN-004 and SYN-020 assets, including out-licensing or partnering.assets.

On OctoberAugust 31,29, 2024,2025, we held our 20242025 Annual Meeting of Stockholders (the “Annual Meeting”). At the Annual Meeting, our stockholders (i) elected Jeffrey J. Kraws, John Monahan, Steven A. Shallcross and Jeffery Wolf as directors; (ii) ratified the appointment of BDO USA P.C. as our independent registered public accounting firm for the year ending December 31, 20242025; (iii) approved an amendment (“Amendment No. 2”) to our 2020 Stock Incentive Plan (the “2020 Stock Incentive Plan”) to (a) increase the number of shares of Commoncommon Stockstock that we will have authority to grant under the 2020 Stock Incentive Plan from 280,000 shares of Common Stock to 2,500,000 shares of Commoncommon Stock and (b)stock to amend the annual non-employee director grant limit to 250,0004,500,000 shares of Commoncommon Stock;stock and (iviii) approvedapproved, on an amendmentadvisory tobasis, the compensation of our Articlesnamed ofexecutive Incorporation to increase the number of authorized shares of Common Stock to 350,000,000 shares.officers.

DuringFor the years ended December 31, 20242025 and 2023,2024, we recognized a $1.4$3.4 million and $1.8$3.2 million, respectively, tax credit receivable and offsettinga corresponding current and non-current deferred R&Dresearch and development tax credit.credit receivable of $1.7 million and $815,000 for the year ended December, 31 2025 and $1.6 million and $762,000 for the year ended December 31, 2024. We participate in a research and development program sponsored by the Spanish government. The program provides for reimbursement of certain expenses incurred in research and development efforts we incurconduct in Spain. The reimbursements can be through either tax credits or direct refunds. The program provides for certain limits on the types and amounts of expenses and requires participants to complete a certification and apply for the refund annually. Subsequent to the period in which expenses are incurred, the program requires participants to maintain certain workforce levels and research and development expenditures over a 24-month period. In the quarter ended June 30, 2023, we completed the certification and applied for direct reimbursement, for our qualifying research and development expenses incurred in the year ended December 31, 2022 . We received approvals from the Spanish government in September and October 2023. The credit will be amortized as a contra-expense over the two-year period 2024 and 2025. In the quarter ended June 30, 2024, we completed the certification and applied for direct reimbursement, for our qualifying research and development expenses incurred in the year ended December 31, 2023. We received approvals from the Spanish government in September and December 2024. The credit will be amortized as a contra-expense over the two-year period 2025 and 2026. In the quarter ended June 30, 2025, we completed the certification and applied for direct reimbursement, for our qualifying research and development expenses incurred in the year ended December 31, 2024. We received approvals from the Spanish government in December 2024. The credit will be amortized as a contra - expense over the two - year period 20252026 and 2026.2027.

¹Additional products with preclinical proof-of-concept include SYN-006 (carbapenemase) to prevent aGVHD, CDI, and microbiome damage in patients treated with carbapenem antibiotics and SYN-007 (ribaxamase) DR to prevent antibiotic associated diarrhea with oral β-lactam antibiotics.

The preparation of our consolidated financial statements in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) which requires the use of estimates, judgments and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the condensed consolidated financial statements, and the reported amounts of expenses in the periods presented. We believe that the accounting estimates employed are appropriate and resulting balances are reasonable; however, due to inherent uncertainties in making estimates, actual results may differ from the original estimates, requiring adjustments to these balances in future periods.

There are accounting policies, each of which requires significant judgments and estimates on the part of management, that we believe are significant to the presentation of our consolidated financial statements. The most significant accounting estimates relate to research and development costs, valuation of GoodwillIPR&D and IPRD, contingent consideration, and impairment of long-lived assets.consideration.

Goodwill represents the excess of the purchase price paid when we acquired VCN in March 2022, over the fair values of the acquired tangible or intangible assets and assumed liabilities. We conduct an impairment test of goodwillIPR&D on an annual basis as of October 1 of each year and will also conduct tests if events occur or circumstances change that would, more likely than not, reduce our fair value below our net equity value.

General and administrative expenses increased to $15.4 million for the year ended December 31, 2025, from $7.4 million for the year ended December 31, 2024, from $7.1 million for the year ended December 31, 2023.2024. This increase of 4%109% is primarily comprised of the contingent consideration adjustment of $700,000$9.0 million due to the VIRAGE Phase 2b clinical trial of VCN-01 (zabilugene almadenorepvec) in thePDAC currentachieving yearits comparedprimary tosurvival aand decreasesafety of $660,000 in the prior, year having a cumulative of $1.4 million,endpoints, offset by a decrease in compensation costs, investor relations costs, consulting fees, and lower director and officer insurance. The charge relating to stock-based compensation expense was $379,000 for the year ended December 31, 2025, compared to $438,000 for the year ended December 31, 2024, compared to $388,000 for the year ended December 31, 2023.2024.

Research and development expenses decreased to $8.6 million for the year ended December 31, 2025, from $12.0 million for the year ended December 31, 2024, from $14.3 million for the year ended December 31, 2023.2024. This decrease of 16%28% is primarily the result of lower clinical trial expenses related to the completion of our VIRAGE Phase 22b clinical trial of VCN-01 (zabilugene almadenorepvec) in PDAC, lower expenses related to our Phase 1a clinical trial of SYN-020, decreased expenses related to our Phase 1b/2a clinical trial of SYN-004 (ribaxamase) in allogeneic HCT recipients and thelower recognitionindirect ofcost therelated researchto and development tax credit,compensation, offset by increasedhigher patent expenses related to the Phase 1 trial of intravitreal VCN-01 in patients with retinoblastoma.SYN-020. We anticipate research and development expense to increasedecrease in 2026 as wea completeresult of the workforce reduction Plan that was implemented on September 30, 2025, the completion of our VIRAGE Phase 2 clinical trial of VCN-01and plan for our Phase 32b clinical trial of VCN-01 in PDAC, advanceand our focus on regulatory interactions around potential pivotal clinical trials of VCN-01 program in PDAC and retinoblastoma, expandthe GMPplanning for VCN-01 manufacturing scale-up manufacturing activities for VCN-01,activities, and continuecontinuing supportingto support our other preclinical and discovery initiatives. In addition, pursuant to the terms of the Rasayana License Agreement that we entered into in February 2026, we will not continue to conduct research and development activities with respect to SYN-020, and do not expect to incur material expenditures in connection therewith since Rasayana is now responsible for all such expenditures including patent expenses. Research and development expenses also include a charge relating to non-cash stock-based compensation expense of $281,000 for the year ended December 31, 2025, compared to $233,000 for the year ended December 31, 2024, compared to $165,000 for the year ended December 31, 2023.2024.

IPRDIPR&D and Goodwill Impairment

During the year ended December 31, 2024, we experienced a sustained decline in the quoted market price of our Commoncommon Stockstock and we deemed this to be a triggering event for impairment. We performed an interim impairment analysis using the "“Income approach"” that requires significant judgments, including primarily the estimation of future development costs, the probability of success in various phases of its development programs, potential post - launch cash flows and a risk - adjusted weighted average cost of capital. We concluded that the in - processin-process R&D with a carrying value of $19.8 million was written down to its estimated fair value of $18.6 million and an impairment charge of $1.3 million was recorded, and goodwill with a carrying value of $5.6 million was written down to its estimated fair value of zero and an impairment charge of $5.6 million was recorded during the year ended December 31, 2024. The decrease in the valuation was primarily driven by an increase in the discount rate which was impacted by an increase in the company specific risk premium, and not by material changes to the clinical and administrative operations of the business. There were no impairments during the year ended December 31, 2025.

Other income was $312,000 for the year ended December 31, 2025, compared to other income of $693,000 for the year ended December 31, 2024,2024. compared to otherOther income of $1,442,000 for the year ended December 31, 2023.2025 is primarily comprised of interest income of $287,000 and foreign currency exchange gain of $25,000. Other income for the year ended December 31, 2024 is primarily comprised of interest income of $697,000 and anforeign currency exchange loss of $4,000. Other income for the year ended December 31, 2023 is primarily comprised of interest income of $1,439,000 offset by an exchange gain of $3,000.

As of December 31, 2024,2025, we havehad a significant accumulated deficit, and with the exception of the three months ended June 30, 2010 and the three months ended December 31, 2017, thewe Company hashave experienced significant losses and incurred negative cash flows since inception. We have incurred an accumulated deficit of $335$358.7 million as of December 31, 2024,2025, and expect to continue to incur losses in the foreseeable future with the recognition of revenue being contingent on successful phasePhase 3 clinical trials and requisite approvals by the FDA or foreign equivalents.

Our cash and cash equivalents totaled $11.6$13.1 million as of December 31, 2024,2025, aan decreaseincrease of $11.6$1.4 million from December 31, 2023.2024. During the yearyears ended December 31, 20242025 and December 31, 2023,2024, the primary use of cash was for working capital requirements and operating activities which resulted in a net loss of $25.7$23.7 million and $18.3$25.7 million, respectively.

With our cash position of approximately $10.5 million in early March 2025, we believe we will be able to fund our operations into the third quarter of 2025. Based on our current plans, we expect that our cash and cash equivalents will be sufficient to completecover ouroverhead ongoingcosts, close out of the VIRAGE Phase 2b clinical trialtrial, ofcommence and complete a potential Phase 2a study evaluating VCN-01 dosing frequency, exploratory VCN-01 (zabilugene almadenorepvec) manufacturing scale-up activities, regulatory interactions regarding proposed VCN-01 clinical trials in PDAC and finalizeretinoblastoma, and preclinical studies supporting VCN-01 and VCN-12, the clinicalfirst study reportcandidate from our VCN-X discovery program. We believe that the trialcash will also be sufficient to fund our committed obligations under the terms of VCN-01the inPurchase retinoblastoma,Agreement related to the Acquisition, but maywill not be sufficient for additional trials of VCN-01, SYN-020VCN-01 or SYN-004,SYN-004 (ribaxamase), or to complete the last cohort of the Phase 1a1b/2a clinical trial of SYN-004, which are expected to require significant cash expenditures. Following the anticipated completion of our ongoing Phase 1 and Phase 22b clinical trials for VCN-01, and preclinical studies supporting VCN-01 and our discovery initiatives, we will need to obtain additional funds for future clinical trials. We anticipate that our future clinical trials will be much larger in size and require larger cash expenditures than the aforementioned clinical programs. We do not have any committed sources of financing for future clinical trials at this time, and it is uncertain whether additional funding will be available when we need it on terms that will be acceptable to us, or at all. Management believes its plan, which is focused on the advancement of VCN-01VCN-01, will allow us to meet our financial obligations, further advance key products, and maintain our planned operations. Based upon our current available funding and our focus on our clinical development of VCN-01 we do not anticipate that we will fund the last cohort of the Phase 1a1b/2a clinical trial of SYN-004 and enrollment in this cohort will not commence unless we obtain grant funding, or find a licensee or partner for the SYN-004 development program. However, the amount of additional capital needed by us will also depend upon the costs to advance our VCN-01 clinical programs. If necessary, weWe may attempt to utilize the atATM theSales market sales facility (the “ATM”)Agreement or seek to raise additional capital in other financing transactions, neither of which is guaranteed. Use of the ATM Sales Agreement is limited by certain restrictions and management’s plan does not rely on additional capital from either of theseany sources. If we are not able to obtain additional capital (which is not assured at this time), our long-term business plan may not be accomplished, and we may be forced to cease certain development activities. More specifically, the completion of any later stage clinical trial will require significant financing or a significant partnership.

There can be no assurance that we will be able to continue to raise funds through the sale of shares of Commoncommon Stockstock through the ATM Sales Agreement or other equity financings. If we raise funds by selling additional shares of Commoncommon Stockstock or other securities convertible into Commoncommon Stock,stock, the ownership interest of our existing stockholders will be diluted. If we are not able to obtain funding for future clinical trials when needed, we will be unable to carry out our business plan and we will be forced to delay the initiation of future clinical trials until such time as we obtain adequate financing and may need to abandon some of our development programs.programs, cease operations, sell or otherwise liquidate our assets or reorganize the Company, or complete a combination of the foregoing.

We have spent, and expect to continue to spend, a substantial amount of funds in connection with implementing our business strategy, including our planned product development efforts, preparation for our planned clinical trials, performance of clinical trials and our research and discovery efforts. Based on our current plans, our cash and cash equivalents will not be sufficient to enable us to meet our near term or long-term expected plans as it is anticipated that we will not have enough cash to continue our operations for the next twelve months from the date of the filing of this Annual Report on Form 10-K. We will be required to obtain additional funding in order to continue the development of certain product candidates within the anticipated time periods (including initiation of planned clinical trials), if at all, and to continue to fund operations at the current cash expenditure levels. We do anticipate that our current cash of approximately $10.5$15.1 million as of early March 20252026 will allow us to coverfund our operations into the first quarter of 2027, including overhead costs, manufacturingclose costsout forof near-termthe VIRAGE Phase 2b clinical supply,trial, exploratory VCN-01 manufacturing costsscale-up ofactivities, regulatory interactions regarding proposed VCN-01 for clinical trial use and limited research efforts, including our ongoing Phase 1 and Phase 2 clinical trials forin VCN-01,PDAC and retinoblastoma, and preclinical studies supporting VCN-01 and VCN-12, the first candidate from our ongoingVCN-X discovery initiatives,program. andWe believe the cash will also be sufficient to fund our committed obligations under the terms of the VCN Share Purchase Agreement (the “VCN Purchase Agreement”) related to the VCNAcquisition; Acquisitionhowever, intopayment of the third$5.0 quartermillion ofowed 2025.to Grifols will significantly deplete our cash and cash equivalents, which could materially and adversely affect our liquidity and limit our ability to fund operations or meet other financial obligations. Our ability to continue as a going concern is dependent upon our ability to obtain additional equity or debt financing, attain further operating efficiencies, reduce expenditures, and, ultimately, to generate revenue. Our notes to the consolidated financial statements included in this Annual Report contain an explanatory paragraph referring to our recurring and continuing losses from operations and expressing substantial doubt in our ability to continue as a going concern without additional capital becoming available. We cannot provide any assurance that we will be able to obtain the required funding to achieve our current business plan, obtain the required regulatory approvals for our product candidates or complete additional corporate partnering or acquisition transactions in order to commercialize such product candidates once regulatory approval is received. If we fail to obtain additional funding for our clinical trials, whether through the sale of securities or a partner or collaborator, and otherwise when needed, we will not be able to execute our business plan as planned and will be forced to cease certain development activities (including initiation of planned clinical trials) until funding is received and our business will suffer, which would have a material adverse effect on our financial position, results of operations and cash flows.

Our ability to continue as a going concern is dependent upon our ability to raise additional capital. Our cash and cash equivalents will not be sufficient to initiate or complete future registrational studies for VCN-01, any potential future trials of SYN-004 (ribaxamase) including Phase 3 clinical programs of SYN-004 (ribaxamase) for prevention of CDI or the Phase 1b/2a clinical study of SYN-004 (ribaxamase) in allogeneic HCT recipients, or later-stage clinical trials of SYN-020.recipients. Therefore, we do not intend to commence future new studies of VCN-01,VCN-01 (zabilugene almadenorepvec) or SYN-004 (ribaxamase) or SYN-020 until we are confident that we have funding necessary to complete such trials. We are actively pursuing additional equity or debt financing,financing opportunities, in the form of either a private placement or a public offering and have been in ongoing discussions with strategic institutional investors and investment banks with respect to such possible offerings. However, we do not currently have commitments from any third parties to provide us with capital. Potential sources of financing that we are pursuing include strategic relationships, licensing arrangements, public or private sales of our equity (including through the ATM Sales Agreement) or debt and other sources. Such additional financing opportunities might not be available to us when and if needed, on acceptable terms or at all. We cannot assure that we will meet the requirements for use of the ATM Sales Agreement especially in light of the fact that we are currently limited by rules of the Securities and Exchange Commission (the “SEC”) as to the number of shares of Commoncommon Stockstock that we can sell pursuant to the ATM Sales Agreement due to the market value of our Commoncommon Stockstock held by non-affiliates. Even if we meet the requirements for use of the ATM,ATM Sales Agreement, there can be no assurance that we will be able to raise funds through the sale of shares of Commoncommon Stockstock through the ATM.ATM Sales Agreement. Additionally, we may seek to access the public or private equity markets when conditions are favorable due to our long-term capital requirements. If we are unable to obtain additional capital (which is not assured at this time), our long-term business plan may not be accomplished and we may be forced to cease certain development activities. More specifically, the completion of future Phase 3 and/or registrational clinical studies will require significant financing or a significant partnership. If we raise funds by selling additional shares of Commoncommon Stockstock or other securities convertible into Commoncommon Stock,stock, the ownership interest of our existing stockholders will be diluted. If we are not able to obtain funding for future clinical trials when needed, we will be unable to carry out our business plan and we will be forced to delay the initiation of future clinical trials until such time as we obtain adequate financing and our operating results and prospects will be adversely affected.

Net cash used in operating activities was $16.9$16.7 million and $19.0$16.9 million during the years ended December 31, 20242025 and 2023,2024, respectively, which was primarily due to the use of funds in our operations related to the development of VCN-01 (zabilugene almadenorepvec) our lead product candidate. Cash used in operating activities for the years ended December 31, 20242025 decreased compared to the same period in 20232024 due primarily to lower research and development expenses and a decrease in interest income, which led to a decrease in net loss.

Cash used in investing activities during the years ended December 31, 20242025 and 20232024 was $1,000$35,000 and $202,000,$1,000, respectivelyrespectively, for equipment purchases.

Our consolidated unaudited financial statements as of MarchJune 31,30, 2026 have been prepared under the assumption that we will continue as a going concern for the next twelve months. Our management concluded that our recurring losses from operations and the fact that we will require additional financing as we continue to execute our business strategy, including the need for additional funds for the commencement of our planned clinical trials, raise substantial doubt about our ability to continue as a going concern for the next twelve months after issuance of our financial statements. In addition, in connection with the filing of our 2025 Form 10-K our independent registered public accounting firm issued a report that included an explanatory paragraph referring to our recurring losses from operations (anticipated continued losses in the future) and net capital deficiency that, as of the date of such report, raised substantial doubt in our ability to continue as a going concern without additional capital becoming available. As of March,June 31,30, 2026 we had cash and cash equivalents of approximately $14.4$11.3 million and as of early MayAugust 2026, we had cash and cash equivalents of $13.1$9.6 million. At June 30, 2026, we had an accumulated deficit of $364 million and working capital of $1.6 million. December 31, 2025, we had an accumulated deficit of $358.7 million and working capital of $7.5 million. As of December 31, 2025, we had cash and cash equivalents of approximately $13.1 million consisting of cash and investments in highly liquid U.S. money market funds. Our ability to continue as a going concern is dependent upon our ability to obtain additional equity or debt financing, attain further operating efficiencies, reduce expenditures and, ultimately, to generate revenue. Our consolidated unaudited financial statements as of MarchJune 31,30, 2026 do not include any adjustments that might result from the outcome of this uncertainty. Based upon the Company’s current business plans, we expect that our current cash will be able to fund operations into the first quarter of 2027.

During the threesix months ended MarchJune 31,30, 2026, our operating activities used net cash of approximately $2.5$5.5 million and our cash and cash equivalents were approximately $14.4$11.3 million as of MarchJune 31,30, 2026. With the exception of the three months ended June 30, 2010 and the three months ended December 31, 2017, we have experienced significant losses since inception and have a significant accumulated deficit. As of MarchJune 31,30, 2026, our accumulated deficit totaled approximately $360.7$364 million on a consolidated basis. Pursuant to the Purchase Agreement entered into in connection with the Acquisition, we have agreed to use reasonable efforts to commercialize VCN-01. Additionally, pursuant to the Purchase Agreement, we agreed to pay up to $70.2 million in contingent consideration upon the achievement of certain milestones, including regulatory filings, of which to date $7.3 million has been paid and an additional $5.0 million has been earned but deferred pending ongoing discussion with Grifols. If we are required to make the deferred $5.0 million milestone payment to Grifols, it will significantly deplete our cash and cash equivalents, which could materially and adversely affect our liquidity and limit our ability to fund operationsoperations, continue clinical research and development activities or meet other financial obligations. We expect to incur additional operating losses in the future and therefore expect our cumulative losses to increase. With the exception of the quarter ended June 30, 2010, and limited laboratory revenues from Adeona Clinical Laboratory, which we sold in March 2012, we have generated very minimal revenues. We do not expect to derive revenue from any source in the near future until we or our potential partners successfully commercialize our products. We expect our expenses to increase in connection with our anticipated activities, particularly as we continue research and development, initiate and conduct clinical trials, and seek marketing approval for our product candidates. Until such time as we receive approval from the FDA and other regulatory authorities for our product candidates, we will not be permitted to sell our products and therefore will not have product revenues from the sale of products. For the foreseeable future we will have to fund all of our operations and capital expenditures from equity and debt offerings, cash on hand, licensing and collaboration fees and grants, if any.

We will need to raise additional capital to fund our operations and meet our current timelines and we cannot be certain that funding will be available on acceptable terms on a timely basis, or at all. The amount of government funding available for grants is dependent upon governmental budgets over which we have no control and which change with new administrations. Based on our current plans, we expect that our current cash will be sufficient to fund operations into the first quarter of 2027 and will only be sufficient to cover overhead costs, commence aan proposedapproved Phase 2a study in metastatic PDAC patients evaluating more frequent VCN-01 dosing for a longer period, conduct exploratory VCN-01 manufacturing scale-up activities, complete regulatory interactions regarding a proposed pivotal clinical trial of VCN-01 in retinoblastoma, and undertake limited preclinical studies supporting VCN-01 and VCN-12, the first candidate from our VCN-X discovery program. We believe our cash will also be sufficient to fund our committed obligations under the terms of the Purchase Agreement related to the Acquisition, but may not be sufficient for additional trials of VCN-01 (other than the planned Phase 2a study evaluating more frequent VCN-01 dosing for a longer period), or SYN-004, or to complete the last cohort of the Phase 1a/2a clinical trial of SYN-004, which are expected to require significant cash expenditures. In addition, based on the significant anticipated cost of a Phase 3 clinical program in a broad indication for SYN-004, we expect it will not be feasible for us to initiate and complete this trial at this time without a partner given the capital constraints tied to our current market cap and share price. We intend to focus our capital on our VCN-01 clinical trials and do not intend to provide further funding for our development of SYN-004 internallyinternally. butAny intend to out-license or partner furtherfuture development of SYN-004.SYN-004 is expected to be funded from out-licensing or partnering for which there can be no assurance. Further development of VCN’s product candidates will require additional funding. To the extent that we raise additional funds by issuing equity securities, our stockholders may experience significant dilution. Any debt financing, if available, may involve restrictive covenants that may impact our ability to conduct our business and also have a dilutive effect on our stockholders. A failure otherwise to secure additional funds when needed in the future whether through an equity or debt financing or a sufficient amount of capital without a strategic partnership could result in us being unable to complete planned preclinical and clinical trials or obtain approval of our product candidates from the FDA and other regulatory authorities. In addition, we could be forced to delay, discontinue or curtail product development, forgo sales and marketing efforts, and forgo licensing in attractive business opportunities, cease operations, sell or otherwise liquidate our assets or reorganize the Company, or complete a combination of the foregoing. Our ability to raise capital through the sale of securities may be limited by the rules of the SEC and NYSE American that place limits on the number and dollar amount of securities that may be sold. There can be no assurances that we will be able to raise the funds needed, especially in light of the fact that our ability to sell securities registered on our registration statement on Form S-3 will be limited until such time the market value of our voting securities held by non-affiliates is $75 million or more. We also may be required to seek collaborators for our product candidates at an earlier stage than otherwise would be desirable and on terms that are less favorable than might otherwise be available.

VCN-01 has been administered to 144 patients acrossin multiple Company- and Investigator-sponsored Phase 1 clinical trials and the Phase 2b VIRAGE trial, and our compassionate use program including patients with pancreatic cancer,cancer (in combination with chemotherapy), head and neck squamous cell carcinoma,carcinoma (with an immune checkpoint inhibitor), ovarian carcinoma,carcinoma (with CAR-T cell therapy), colorectal cancer, and retinoblastoma.retinoblastoma (by intravitreal injection). VCN-01 has also been made available for compassionate use in retinoblastoma patients, and 2 patients have been treated in this program.

Additionally, as part of our strategic transformation into an oncology focused company, we are exploring value creation options for our SYN-004 asset, including out-licensing or partnering as we do not intend to continue clinical trial activities or further develop SYN-004 without receipt of grant funding or funding through a partnership or other collaboration.

During the threesix months ended MarchJune 31,30, 2026, we sold 10,204,319 shares of our Common Stock pursuant to the Amended and Restated At The Market Issuance Sales Agreement, dated February 9, 2021, as amended by Amendment No. 1 thereto, dated May 3, 2021, as further amended by Amendment No. 2 thereto, dated May 2, 2024 (the “ATM Sales Agreement”) and received net proceeds of approximately $2.3 million. On January 22, 2026, we received $1.6 million for the 2024 Research and Development rebate program sponsored by the Spanish government. The program provides for reimbursement of certain expenses incurred in research and development efforts we incur in Spain. The reimbursements can be through either tax credits or direct refunds.

¹Final †Phase 1b/2a study remains open, but enrollment paused after completing 2 of 3 scheduled cohorts; conduct of the third cohort is contingent on grant funding or a partnership.

IntravenousPhase 2 Trial of intravenous VCN-01 with nab-paclitaxel plus gemcitabine for the treatment ofin patients with metastatic PDAC

On March 23, 2026, we announced the outcomes of a recent Type Bpositive End-of-Phase 2 (EOP2) meetingMeeting with the U.S. FoodFDA and Drug Administration (the “FDA”) regardingRegarding the designDesign of a Phase 3 clinical studyTrial of our lead clinical candidate VCN-01 in combinationMetastatic withPancreatic standard-of-careDuctal (“SoC”) chemotherapy for the treatment of metastatic pancreatic ductal adenocarcinoma (“PDAC”).Adenocarcinoma.

The FDA provided general agreement with our proposed design for a Phase 3 clinical trial, which closely tracks the design of the successful VIRAGE Phase 2 trial. As announced in 2025, the VIRAGE trial met its primary endpoints, with metastatic PDAC patients receiving VCN-01 with SoC chemotherapy having improved overall survival (OS), progression free survival (PFS) and Duration of Response (DoR) compared to SoC chemotherapy alone. Greater improvements in OS and PFS were observed in patients who received two doses of VCN-01, leading usTheriva to plan the Phase 3 trial to include repeat dosing and an adaptive design aimed to optimize the trial’s timelines and outcomes.

Consistent with scientific advice previously received from the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (the “EMA”),EMA, the FDA advised that a potential biologics licenselicensing application (BLA) for VCN-01 in metastatic PDAC could be supported by our proposed Phase 3 clinical trial (if successful) comprising a single, high-quality, randomized, double-blinded, study comparing VCN-01 plus gemcitabine/nab-paclitaxel SoC to gemcitabine/nab-paclitaxel SoC plus placebo. The FDA further agreed on the proposed dosing of VCN-01 and gemcitabine/nab-paclitaxel in repeated “macrocycles” (enabling more than 2 doses of VCN-01 to be administered in the Phase 3 trial), the proposed inclusion/exclusion criteria, the primary endpoint (OSoverall survival), key secondary endpoints (including PFSprogression free survival), and the use of an adaptive design. The FDA also clarified statistical expectations regarding the proposed interim analyses and the quality of data required for potential sample size re-estimation or a demonstration of early efficacy.

In the first quarter of 2026, we made VCN-01 available to investigators at Hospital Sant Joan de Déu, Barcelona, for compassionate use in treating patients with retinoblastoma. Two patients have been treated with intravitreal VCN-01 in combination with intravitreal topotecan and patients are being followed by the treating physicians. We expect that outcomes from these compassionate use patients will provide valuable information on the feasibility and tolerability of this combination for use in a potential Phase 2/3 clinical trial.

As previously disclosed, preclinical data demonstrate potential antitumor synergy between VCN-01 and topoisomerase I inhibitors, such as topotecan. We believe that intravitreal coadministration of VCN-01 with topotecan may provide a new treatment option for children with refractory retinoblastoma andwith vitreous seeds,seeds that are refractory/resistant to the use of current intravitreal chemotherapy, which remains an unmet medical need in patients with this ultra rare disease.patient Discussionspopulation. areExtensive on-goingdiscussions with clinicians and key opinion leaders tohave enabled the design a Phase 2/3 clinical trial protocol for the VCN-01 + topotecan combination in this ultra rare patient population.population, Weand expectwe thatplan outcomesto from these compassionate use patients will provide valuable information ondiscuss the feasibilityproposed andprotocol tolerabilitywith ofthe this combination for useFDA in aQ3 potential Phase 2/3 clinical trial.2026.

We anticipate that the trialcost for the Phase 2/3 trial would be approximately $12$9 million (including chemistry, manufacturing and controls). If a protocol is ultimately submitted to, and agreed by, the FDA, we expect the first patient to be enrolled in DecemberJanuary 2026,2027, with rolling BLA submissions expected to be made in 2029 (if successful), targeting potential approval of the BLA prior to the current legislative deadline of September 30, 2029 deadline to be eligible to receive a Priority Review Voucher. We have revised our estimate of the Phase 2/3 trial cost downward from our estimate of $12 million, as disclosed in our Quarterly Report on Form 10-Q for the quarter ended March 31, 2026, based on a reduced requirement for clinical drug product manufacture , and have adjusted the anticipated first-patient enrollment from December 2026 to January 2027.

Three Months Ended MarchJune 31,30, 2026 and 2025

General and administrative expenses increaseddecreased to $2.1$2.0 million for the three months ended MarchJune 31,30, 2026, from $1.4$11.2 million for the three months ended MarchJune 31,30, 2025. This increasedecrease of 43%82% is primarily comprised of anthe prior year increase in fair value of the contingent consideration adjustment of $9.2 million due to the VIRAGE Phase 2b clinical trial of VCN-01 in PDAC achieving its primary survival and safety endpoints, offset set by current year increase in legal fees, investor relation costs, registration fees, and salary costs.fees. The charge related to stock-based compensation expense was $111,000$110,000 for the three months ended MarchJune 31,30, 2026, compared to $54,000$97,000 for the three months ended MarchJune 31,30, 2025.

Research and development expenses decreased to $355,000 for the three months ended March 31, 2026, from approximately $3.0$1.3 million for the three months ended MarchJune 31,30, 2026, from approximately $2.0 million for the three months ended June 30, 2025. This decrease of 88%35% is primarily the result of lower clinical trial expenses related to the completion of our VIRAGE Phase 2b clinical trial of VCN-01 in PDAC, the recognition of the Spanish research and development rebate, lower indirect cost related to compensation expense and lower direct clinical trial expenses related to our Phase 1b/2a clinical trial of SYN-004 (ribaxamase) in allogeneic HCT recipients,recipients and lower expenses related to SYN-020, offset by higher patentdirect expenses related to SYN-020.VCN-01 manufacturing activities and expenses associated with the planning for the Phase 2a study in metastatic PDAC patients evaluating more frequent VCN-01 dosing for a longer period. We anticipate research and development expense to decrease in the near future until we commence additional clinical trials as we focus on regulatory interactions regarding a proposed pivotal clinical trial of VCN-01 in retinoblastoma, continueconduct withexploratory VCN-01 manufacturing scale-up activities, commence a proposed Phase 2a study in metastatic PDAC patients evaluating more frequent VCN-01 dosing for a longer period and continue limited preclinical studies supporting VCN-01 and VCN-12, the first candidate from our VCN-X discovery program. The charge related to stock-based compensation expense was $24,000$25,000 for the three months ended MarchJune 31,30, 2026, compared to $46,000$76,000 for the three months ended MarchJune 31,30, 2025.

The following table sets forth our research and development expenses directly related to our product candidates for the three months ended MarchJune 31,30, 2026 and 2025. These direct expenses were external costs associated with preclinical studies and clinical trials. Indirect research and development expenses related to employee costs, facilities, stock-based compensation and research and development support services that are not directly allocated to specific product candidates.

Other income was $83,000$78,000 for the three months ended MarchJune 31,30, 20262026, compared to other income of $93,000$74,000 for the three months ended MarchJune 31,30, 2025. Other income for the three months ended MarchJune 31,30, 2026 is comprised of interest income of $82,000$79,000 and an exchange gainloss of $1,000. Other income for the three months ended MarchJune 31,30, 2025 is comprised of interest income of $96,000$54,000 and an exchange lossgain of $3,000.$20,000.

Our net loss for the three months ended MarchJune 31,30, 2026 was $2.0$3.2 million, or ($0.05$0.07) per common share, compared to $4.3$13.1 million, or ($1.55$1.93) per common share, for the three months ended MarchJune 31,30, 2025.

Historically, we have financed our operations primarily through public and private sales of our securities, and we expect to continue to seek and obtain additional capital in a similar manner. During the year ended December 31, 2025, our primary sources of cash were the approximately $6.8 million in net proceeds received from sales of our Common Stock under the ATM Sales Agreement, approximately $3.9 million in net proceeds from the exercise of existing warrants by holders pursuant to a warrant inducement agreement, the $1.7 million received for the Research and Development rebate program, $1.4 million for the THERICEL project loan from the National Knowledge Transfer Program of the Spanish government’s Ministry of Science and, in May 2025, we closed our May 2025 Offering of 6,818,180 shares of Common Stock (or pre-funded warrants in lieu thereof) in combination with accompanying common stock purchase warrants to purchase an aggregate of 6,818,180 shares of our Common Stock for gross proceeds of $7.5 million (net proceeds of $6.7 million, after deducting underwriting discounts and expenses). During the threesix months ended MarchJune 31,30, 2026, the onlyprimary source of cash was from the $300,000 up-front payment received for the out-licensing agreement of SYN-020, $1.6 million received for the Research and Development rebate program and $2.3 million in net proceeds received from sales of our Common Stock under the ATM Sales Agreement.

As of MarchJune 31,30, 2026, we have a significant accumulated deficit, and with the exception of the three months ended June 30, 2010 and the three months ended December 31, 2017, we have experienced significant losses and incurred negative cash flows since inception. We have incurred an accumulated deficit of $360.8$364 million as of MarchJune 31,30, 2026, and expect to continue to incur losses in the foreseeable future with the recognition of revenue being contingent on successful phase 3 clinical trials and requisite approvals by the FDA or foreign equivalents and the success of our licensee.

Our cash and cash equivalents totaled $14.4$11.3 million as of MarchJune 31,30, 2026, ana increasedecrease of $1.4$1.7 million from December 31, 2025. During the year ended December 31, 2025 and quartersix months ended MarchJune 31,30, 2026, the primary use of cash was for working capital requirements and operating activities, which resulted in a net loss of $23.7 million and $2.0$5.3 million for the year ended December 31, 2025 and the quartersix months ended MarchJune 31,30, 2026, respectively.

With our cash position of $13.1$9.6 million as of early MayAugust 2026, we believe we will be able to fund our operations into the first quarter of 2027; however, the current cash will only be sufficient to runconduct certain clinicallimited trialsclinical, regulatory, manufacturing, and nopreclinical assurancesactivities canas bedescribed providedherein and our cash runway could differ materially from our expectations based on various factors, many of which are out of our control. We continue to experience operating losses and face significant uncertainties related to our business model, market conditions, clinical trial outcomes, FDA review timelines and strategic initiatives. These factors raise substantial doubt about our ability to continue as a going concern beyond the next twelve months without additional capital or other strategic actions. Management has developed plans intended to mitigate these uncertainties, including pursuing strategic collaborations, securing additional financing, prioritizing key development programs and pursuing other strategic alternatives, that may include a business combination, merger or reverse merger. There can be no assurance that such actions will be sufficient to alleviate the going concern uncertainty.

Based on our current plans, we expect that our cash and cash equivalents will be sufficient to cover overhead costs, commence aan proposedapproved Phase 2a study evaluating more frequent VCN-01 dosing for a longer period, exploratory VCN-01 manufacturing scale-up activities, regulatory interactions regarding a proposed pivotal clinical trial of VCN-01 in retinoblastoma, and limited preclinical studies supporting VCN-01 and VCN-12, the first candidate from our VCN-X discovery program. We believe that the cash will also be sufficient to fund our committed obligations under the terms of the Share Purchase Agreement entered into in connection with the Acquisition (the “Purchase Agreement.Agreement”), however, payment of the $5.0 million owed to Grifols Innovation and New Technologies Limited will significantly deplete our cash and cash equivalents, which could materially and adversely affect our liquidity and limit our ability to fund operations or meet other financial obligations. Our current cash will not be sufficient for additional trials of VCN-01 (other than the planned Phase 2a study evaluating more frequent VCN-01 dosing for a longer period), or additional trials of SYN-004 (ribaxamase), or to complete the last cohort of the Phase 1b/2a clinical trial of SYN-004, which are expected to require significant cash expenditures. Following the completion of our ongoing Phase 1 and Phase 2b clinical trials for VCN-01, and limited preclinical studies supporting VCN-01 and our discovery initiatives, we will need to obtain additional funds for future clinical trials. We anticipate that our future clinical trials will be much larger in size and require larger cash expenditures than the aforementioned clinical programs. We do not have any committed sources of financing for future clinical trials at this time, and it is uncertain whether additional funding will be available when we need it on terms that will be acceptable to us, or at all. Management believes its plan, which is focused on the advancement of VCN-01, will allow us to meet our financial obligations, further advance key products, and maintain our planned operations. Based upon our current available funding and our focus on our clinical development of VCN-01 we do not anticipate that we will fund the last cohort of the Phase 1b/2a clinical trial of SYN-004 and enrollment in this cohort will not commence unless we obtain grant funding, or find a licensee or partner for the SYN-004 development program. However, the amount of additional capital needed by us will also depend upon the costs to advance our VCN-01 clinical programs.

Net cash used in operating activities was $2.5$5.5 million and $4.8$9.5 million during the threesix months ended MarchJune 31,30, 2026 and 2025, respectively, which was primarily due to the use of funds in our operations related to the development of VCN-01. Cash used in operating activities for the threesix months ended MarchJune 31,30, 2026 decreased compared to the same period in 2025 due primarily to prior year contingent consideration adjustment, and lower research and development expenses due to completion of trials offset by higher legal and investor relation costs, which led to a decrease in net loss.

There was no cashCash used in investing activities during the threesix months ended MarchJune 31,30, 2026 and 2025.2025 was $3,000 and $16,000, respectively, for equipment purchases.

Cash UsedProvided inby Financing Activities

Cash provided by financing activities during the threesix months ended MarchJune 31,30, 2026 included at the market offering proceeds of $2.3 million from sales of 10,204,319 shares of our Common Stock under the ATM Sales Agreement, and $1.6 million received for the research and development tax credit offset by payments of loans payable of $49,000.$60,000. Cash provided by financing activities during the threesix months ended MarchJune 31,30, 2025 included $1.7$1.8 million received for the research and development tax credit andcredit, $1.4 million in loan proceeds from the THERICEL project loan and $6.9 million in net proceeds from the sale of Common Stock, offset by payments of loans payablein the amount of $56,000.$67,000.

During the three months ended MarchJune 31,30, 2026, we did not have, and we do not currently have, any off-balance sheet arrangements, as defined under SEC rules.

We have made certain accounting policy elections whereby we (i) do not recognize ROU assets or lease liabilities for short-term leases (those with original terms of 12-months or less) and (ii) combine lease and non-lease elements of our operating leases. As of MarchJune 31,30, 2026, we did not have any material finance leases.