What changed in this filing

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Item 8. Financial Statements and Supplementary Data

2026-03-12 compared with 2025-03-06 · 355 added, 281 removed, 870 unchanged (42% of the section changed)

34 unchanged sentences

We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matters

The critical audit matters communicated below are matters arising from the current period audit of the consolidated financial statements that were communicated or required to be communicated to the audit committee and that:

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current period audit of the consolidated financial statements that were communicated or required to be communicated to the audit committee and that:

(1) relate to accounts or disclosures that are material to the consolidated financial statements and (2) involved our especially challenging, subjective, or complex judgments.

The communication of critical audit matters does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matters below, providing separate opinions on the critical audit matters or on the accounts or disclosures to which they relate.

The communication of the critical audit matter does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which they relate.

Contingent Consideration – Fair value measurement

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and (ii) evaluating the discount rate applied to future milestone payment periods.

In-Process Research and Development and Goodwill Impairment Assessment

As described in Notes 3 and 4 to the consolidated financial statements, the Company’s consolidated balances of In-process Research and Development (“IPR&D”) indefinite-lived intangible asset and Goodwill were $17.4 million and $0, respectively, as of December 31, 2024.

The Company reviews goodwill for impairment at least annually or more frequently if events or circumstances indicate the carrying value at the reporting unit level might exceed its fair value.

The IPR&D indefinite-lived intangibles are tested annually for impairment, or more frequently if events or circumstances indicate it is more likely than not the fair value is less than their carrying value.

The Company estimates the fair value of its reporting unit and certain IPR&D using an income approach.

The Company identified triggering events during 2024 and performed impairment analyses for Goodwill and certain IPR&D resulting in total impairment charges recorded of $5.6 million and $1.3 million, respectively.

We identified the determination of the fair value of the Company’s reporting unit and certain IPR&D as a critical audit matter.

Under the income approach, the key assumptions used in the determination of the fair value of the reporting unit include estimates of future cash flows and the discount rate applicable to those future cash flow periods.

The key assumptions used in the determination of the fair value of certain IPR&D assets using the income approach include estimates of future cash flows and the discount rate applicable to those future cash flow periods.

Changes to these key assumptions could have a significant impact on the measurement of the fair value of the reporting unit and certain IPR&D.

Auditing management’s valuation methods and these assumptions involve especially challenging and

subjective auditor judgment due to the nature and extent of auditor effort required to address these matters, including the specialized knowledge and skill needed.

The primary procedures we performed to address this critical audit matter included:

- Evaluating the reasonableness of estimated future cash flows by comparing management’s assumptions to comparable external market and industry data.

- Utilizing personnel with specialized knowledge and skills in valuation to assist in:

(i) evaluating the reasonableness of valuation methods;

(ii) testing the mathematical accuracy of the Company’s calculations;

(iii) evaluating the reasonableness of the implied control premium;

and (iv) evaluating the reasonableness of the discount rate applied to future cash flows.

/s/ BDO USA, P.C .

We have served as the Company’s auditor since 2012.

Raleigh, North Carolina

March 12, 2026

We have served as the Company's auditor since 2012.

Theriva Biologics, Inc.

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Total Liabilities

Commitments and Contingencies

Temporary Equity;

10,000,000 authorized

Series C convertible preferred stock, $ 0.001 par value;

10,000,000 authorized;

0 issued and outstanding at December 31, 2024, and 275,000 issued and outstanding at December 31, 2023

Series D convertible preferred stock, $ 0.001 par value;

10,000,000 authorized;

0 issued and outstanding at December 31, 2024 and 100,000 issued and outstanding at December 31, 2023

Commitments and Contingencies (Note 12)

Stockholders’ Equity:

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Treasury stock at cost, 28,809 shares at December 31, 2025 and at December 31, 2024

Accumulated other comprehensive (loss) income

Accumulated other comprehensive income (loss)

Accumulated deficit

1 unchanged sentence

Total Liabilities and Stockholders’ Equity

All share numbers have been retrospectively adjusted for the one to twenty-five reverse stock split effective August 26, 2024

See accompanying notes to consolidated financial statements

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Other Income:

Foreign currency exchange (loss) gain

Foreign currency exchange gain (loss)

Interest income

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Income tax benefit

Less deemed dividend from warrant inducement

Net Loss Attributable to Common Stockholders

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Weighted average number of shares outstanding during the period - basic and dilutive

(Loss) gain (loss) on foreign currency translation

Gain (loss) on foreign currency translation

Total comprehensive loss

All share numbers have been retrospectively adjusted for the one to twenty-five reverse stock split effective August 26, 2024

See accompanying notes to consolidated financial statements

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Stock issued under “at-the-market” offering

Foreign currency exchange gains

Issuance of Common Stock and Warrants, net of issuance costs

Series C Preferred Stock conversion to Common

Series D Preferred Stock conversion to Common

Conversion of Pre-Funded Warrants to Common

Foreign currency exchange loss

Balance at December 31, 2024

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Issuance of Common Stock and Warrants, net of issuance costs

Series C Preferred Stock conversion to Common

Series D Preferred Stock conversion to Common

Warrant Inducement, net of issuance costs

Conversion of Pre-Funded Warrants to Common

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Balance at December 31, 2025

All share numbers have been retrospectively adjusted for the one to twenty-five reverse stock split effective August 26, 2024

See accompanying notes to consolidated financial statements

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Stock-based compensation

Income tax benefit

In-process research and development impairment

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Change in fair value of contingent consideration

Payment of contingent consideration

Loss on asset disposal

Non - cash lease expense

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Proceeds from issuance Common Stock and Warrants offering, net of issuance costs

Proceeds from warrant inducement

Proceeds from long term debt

Proceeds from issuance of common stock for warrant exercises

Tax credit receivable

Net Cash Provided By Financing Activities

Effects of exchange rate changes on cash and cash equivalents

Net decrease in cash and cash equivalents and restricted cash

Net increase (decrease) in cash and cash equivalents and restricted cash

Cash and cash equivalents and restricted at the beginning of this period

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Total cash, cash equivalents, and restricted cash shown in the statement of cash flows

Supplemental non-cash investing and financing activities:

Conversion of Series C Preferred Stock to Common Shares

Conversion of Series D Preferred Stock to Common Shares

Right of use assets obtained in exchange for lease liabilities

All share numbers have been retrospectively adjusted for the one to twenty-five reverse stock split effective August 26, 2024

NONCASH FINANCING ACTIVITIES:

Noncash equity issuance costs and deemed dividend

See accompanying notes to consolidated financial statements

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Theriva Biologics, Inc.

(the “Company” or “Theriva Biologics”) is a diversified clinical-stage company developing therapeutics in areas of high unmet need.

As a result of the acquisition in March 2022 of Theriva Biologics S.L.

(“VCN”, formerly known as VCN Biosciences, S.L.) (the “Acquisition”), described in more detail below, the Company transitioned its strategic focus to oncology through the development of VCN’s new oncolytic adenovirus platform designed for intravenous and intravitreal delivery to trigger tumor cell death, to improve access of co-administered cancer therapies to the tumor, and to promote a robust and sustained anti-tumor response by the patient’s immune system.

Prior to the Acquisition, the Company’s focus was on developing therapeutics designed to treat gastrointestinal (GI) diseases in areas which included its 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.

(the “Company” or “Theriva Biologics”) is a diversified clinical-stage company developing therapeutics designed to treat cancer and related diseases in areas of high unmet need.

As a result of the Company’s acquisition of Theriva Biologics, S.L.

(“VCN”, formerly named VCN Biosciences, S.L.), in March 2022 described in more detail below (the “Acquisition”), we transitioned our strategic focus to oncology through the development of VCN’s new oncolytic adenovirus platform designed for intravenous and intravitreal delivery to trigger tumor cell death, to improve access of co-administered cancer therapies to the tumor, and to promote a robust and sustained anti-tumor response by the patient’s immune system.

Our lead product candidate, VCN-01 (zabilugene almadenorepvec), is a clinical stage oncolytic human adenovirus that is modified for tumor-selective replication and to express an enzyme, PH20 hyaluronidase.

VCN-01 has been evaluated in a Phase 2b clinical study for the treatment of pancreatic cancer (“VIRAGE”), and a Phase 1 clinical study for the treatment of retinoblastoma, as well as various other Phase 1 clinical studies for the treatment of other solid tumors including head and neck squamous cell carcinoma.

Corporate Structure and Basis of Presentation

On August 15, 2024, the Board of Directors of the Company approved a reverse stock split of the Company’s authorized, issued and outstanding shares of common stock, par value $ 0.001 per share, at a ratio of one (1) share of common stock for every twenty - five (25) shares of common stock (the “Reverse Stock Split”).

The Reverse Stock Split was effective on August 26, 2024 (the “Effective Time).

As a result of the Reverse Stock Split, each twenty - five (25) pre-split shares of common stock outstanding will automatically combine into one (1) new share of common stock without any action on the part of the holders, and the number of outstanding shares common stock will be reduced from 25,131,230 shares to 1,005,249 shares (subject to rounding of fractional shares) and the number of authorized shares of common stock was reduced from 350,000,000 share to 14,000,000 shares and then increased to 350,000,000 after obtaining approval of the Company’s shareholders at the 2024 annual meeting of stockholders.

On August 15, 2024, the Board of Directors of the Company approved a reverse stock split of the Company’s authorized, issued and outstanding shares of common stock, par value $ 0.001 per share (“Common Stock”), at a ratio of one (1) share of Common Stock for every twenty - five (25) shares of Common Stock (the “Reverse Stock Split”).

The Reverse Stock Split went effective on August 26, 2024 (the “Effective Time).

As a result of the Reverse Stock Split, each twenty - five (25) pre-split shares of Common Stock outstanding automatically combined into one (1) new share of common stock without any action on the part of the holders, and the number of outstanding shares of Common Stock was reduced from 25,131,230 shares to 1,005,249 shares and the number of authorized shares of Common Stock was reduced from 350,000,000 shares to 14,000,000 shares and then increased back to 350,000,000 shares of Common Stock after obtaining approval of the Company’s shareholders at the 2024 annual meeting of stockholders.

Stockholders who otherwise were entitled to receive fractional shares because they held a number of pre-reverse stock split shares of the Company’s Common Stock not evenly divisible by 25, received, in lieu of a fractional share, that number of shares rounded up to the nearest whole share.

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In addition, pursuant to their terms, a proportionate adjustment was made to the per share conversion exercise price and number of shares issuable under all of the Company’s outstanding shares of convertible preferred stock and stock options and warrants to purchase shares of Common Stock, and the number of shares authorized and reserved for issuance pursuant to the Company’s equity incentive plans was reduced proportionately.

All affected share amounts and exercise/conversion prices in the condensed consolidated financial statements and footnotes below have been adjusted retrospectively for the Reverse Stock Split.

All affected share amounts and exercise/conversion prices in the consolidated financial statements and footnotes below have been adjusted retroactively for the Reverse Stock Split.

As of December 31, 2025, the Company had nine subsidiaries, Theriva Biologics, S.L., Pipex Therapeutics, Inc.

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All statements of operations, equity and cash flows for each of the entities are presented as consolidated.

All subsidiaries were formed under the laws of the State of Delaware on January 8, 2001, except for EPI, which was incorporated in Delaware on December 12, 2000, Epitope which was incorporated in Delaware in January 2002, Putney which was incorporated in Delaware in November 2006, Healthmine which was incorporated in Delaware in December 2007 and SYN Biomics which was incorporated in Nevada in December 2013.

All subsidiaries were formed under the laws of the State of Delaware on January 8, 2001, except for EPI, which was incorporated in Delaware on December 12, 2000;

Epitope which was incorporated in Delaware in January 2002;

Putney which was incorporated in Delaware in November 2006;

Healthmine which was incorporated in Delaware in December 2007;

SYN Biomics which was incorporated in Nevada in December 2013;

and Theriva Biologics, S.L.

which was incorporated in Spain in December 2022.

As of December 31, 2025, the Company had a significant accumulated deficit of $ 358.7 million, and the Company has experienced significant losses and incurred negative cash flows since inception.

The Company expects to continue incurring losses for 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.

Historically, the Company has financed its operations primarily through public and private sales of its common stock and a private placement of its preferred stock, and it expects to continue to seek to obtain required capital in a similar manner.

Historically, the Company has financed its operations primarily through public and private sales of its Common Stock and a private placement of its preferred stock as well as warrant exercises, and it expects to continue to seek to obtain required capital in a similar manner.

The Company has spent, and expects to continue to spend, a substantial amount of funds in connection with implementing its business strategy, including planned product development efforts, clinical trials and research and discovery efforts.

The Company’s cash and cash equivalents totaled $ 11.6 million as of December 31, 2024, a decrease of $ 11.6 million from December 31, 2023.

The Company’s cash and cash equivalents totaled $ 13.1 million as of December 31, 2025, an increase of $ 1.4 million from December 31, 2024.

During the year ended December 31, 2025, the primary use of cash was for working capital requirements and operating activities which resulted in a net loss of $ 23.7 million.

The Company believes it will be able to fund its operations into the third quarter of 2025.

However, the actual amount of additional capital needed by the Company will also depend upon the costs to advance its VCN-01 clinical programs and whether it continues to develop SYN-004 internally, or out-licenses or partners such development.

If necessary, the Company may attempt to utilize the at-the-market offering facility (“ATM”) or seek to raise additional capital in other financing transactions, neither of which is guaranteed.

The Company believes it will be able to fund its operations into the first quarter of 2027.

However, the actual amount of additional capital needed by the Company will also depend upon the costs to advance its VCN-01 (zabilugene almadenorepvec) clinical programs.

At this time, the Company does not intend to continue to develop SYN-004 and/or SYN-020 internally due to the cost to do so and is seeking out-licenses or partners for such development.

The Company may attempt to utilize the at-the-market offering facility (“ATM”) or seek to raise additional capital in other financing transactions, neither of which is guaranteed.

Use of the ATM is limited by certain restrictions and management’s plan does not rely on additional capital from either of these sources.

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The Company continues to incur losses and, as of December 31, 2025, the Company had an accumulated deficit of approximately $ 358.7 million.

Since inception, the Company has financed its activities principally from the proceeds from the issuance of equity securities.

The Company’s ability to continue as a going concern is dependent upon the Company’s ability to raise additional debt and equity capital.

Since inception, the Company has financed its activities principally from the proceeds of the issuance of equity securities.

The Company’s ability to continue as a going concern is dependent upon the Company’s ability to raise additional debt and equity capital or secure a potential license or strategic relationship that can help fund its clinical development activities.

There can be no assurance that such capital will be available in sufficient amounts or on terms acceptable to the Company.

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The accompanying consolidated financial statements do not include any adjustments relating to the recoverability of the recorded assets or the classification of liabilities that may be necessary should the Company be unable to continue as a going concern.

The Company does not have sufficient capital to fund its operations beyond the next twelve months.

In order to address the Company’s capital needs, including its planned clinical trials, the Company is actively pursuing additional equity or debt financing in the form of either a private placement or a public offering.

The Company has been in ongoing discussions with strategic institutional investors and investment banks with respect to such possible offerings.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Going Concern – (continued)

The Company continues to experience operating losses and faces significant uncertainties related to its business model, market conditions, and strategic initiatives.

These factors raise substantial doubt about the Company’s ability to continue as a going concern beyond the next twelve months without additional capital, or other strategic actions.

The Company has been in ongoing discussions with strategic institutional investors and investment banks with respect to such possible offerings and licensing and/or partnership arrangements.

Such additional financing opportunities might not be available to the Company when and if needed, on acceptable terms or at all.

If the Company is unable to obtain additional financing in sufficient amounts or on acceptable terms under such circumstances, the Company’s operating results and prospects will be adversely affected.

On September 28, 2025, the Board of Directors of the Company approved a plan to resize and restructure the Company (the “Plan”) for purposes of focusing its attention on business development and licensing activities and the Company’s upcoming meetings with the U.S.

Food and Drug Administration and the European Medicines Agency for planned clinical trials in patients with metastatic pancreatic ductal adenocarcinoma (“PDAC”) and retinoblastoma.

The Company’s lead product candidate, VCN-01 (zabilugene almadenorepvec), a clinical stage oncolytic human adenovirus that is modified for tumor-selective replication and to express an enzyme, PH20 or hyaluronidase, has been evaluated in a Phase 2b 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.

Pursuant to the Plan, on September 30, 2025, the Company implemented a workforce reduction of seven employees or 32 % of the then global Company workforce.

The goal of this reduction was to direct the Company’s resources towards business development and licensing activities and clinical trial planning and preparation for potential pivotal trials of VCN-01 in patients with PDAC and retinoblastoma, which it believes will represent its best opportunity for success.

The Company completed the employee reduction immediately and incurred a total of approximately $ 520,000 in charges in connection with the workforce reduction.

These charges consisted primarily of cash severance and benefits over a three-month period, in connection with the workforce reduction.

The Plan is expected to save approximately $ 1.8 million in compensation and benefits annually beginning in 2026, and together with additional anticipated operating cost reductions the Company expects that it will extend its cash runway into the first quarter of 2027;

however, as described below, the current cash will only be sufficient to run certain clinical trials and no assurances can be provided and our cash could differ materially from our expectations based on various factors, many of which are out of our control.

The estimates of the charges and expenditures that the Company expects to incur in connection with the workforce reduction, and the timing thereof, are subject to a number of assumptions, including local law requirements in various jurisdictions, and actual amounts may differ materially from estimates.

The Company may also incur other charges or cash expenditures not currently contemplated due to unanticipated events that may occur.

Theriva Biologics, Inc.

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At December 31, 2025, the Company had cash and cash equivalents of approximately $ 13.1 million.

Based upon the Company’s current business plans, management believes that the Company’s current cash on hand will be sufficient to fully execute its plans into the third quarter of 2025.

Based upon the Company’s current business plans, management believes that the Company’s current cash on hand will be sufficient to fully execute its plans into the first quarter of 2027.

Commencement of planned future clinical trials is subject to the Company’s successful pursuit of opportunities that will allow it to establish the clinical infrastructure and financial resources necessary to successfully initiate and complete its plan.

The Company anticipates its current cash will allow it to cover overhead costs, manufacturing costs for near - term clinical supply and limited research efforts, including completing its funding requirements for its ongoing current trials for VCN-01.

The Company will be required to obtain additional funding in order to continue the development of its current product candidates within the anticipated time periods (including initiation of its planned future clinical trials), if at all, and to continue to fund operations at the current cash expenditure levels.

The Company anticipates its current cash will allow it to cover overhead costs, close out of the VIRAGE Phase 2b clinical trial, exploratory VCN-01 (zabilugene almadenorepvec) manufacturing scale-up activities, regulatory interactions regarding proposed VCN-01 clinical trials in PDAC and retinoblastoma, and preclinical studies supporting VCN-01 and VCN-12, the first candidate from our VCN-X discovery program.

The Company also believes that the cash will be sufficient to fund its committed obligations under the terms of the VCN Share Purchase Agreement entered into in connection with the Acquisition (the “Purchase Agreement”), but will not be sufficient for additional trials of VCN-01, or SYN-004, 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 the Company’s ongoing Phase 1 and Phase 2b clinical trials for VCN-01, complete and commence a potential Phase 2a study evaluating VCN-01 dosing frequency, and preclinical studies supporting VCN-01 and its discovery initiatives, the Company will need to obtain additional funds for future clinical trials.

The Company anticipates that its future clinical trials will be much larger in size and require larger cash expenditures than the aforementioned clinical programs and limited preclinical research efforts.

Currently, the Company does not have commitments from any third parties to provide it with capital.

Potential sources of financing include strategic relationships, public or private sales of equity (including through its at the market offering sales agreement (the "ATM Sales Agreement")) or debt and other sources.

The Company cannot assure that it will meet the requirements for use of the ATM Sales Agreement or that additional funding will be available on favorable terms at all.

Potential sources of financing include strategic relationships, public or private sales of equity (including through its 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”)) or debt and other sources.

The Company cannot assure that it will meet the requirements for use of the ATM Sales Agreement or that additional funding will be available on favorable terms or at all.

If the Company fails to obtain additional funding for its clinical trials, whether through the sale of securities or a partner or collaborator, and otherwise when needed, it will not be able to execute its business plan as planned and will be forced to cease certain development activities (including initiation of planned clinical trials) until funding is received and its business will suffer, which would have a material adverse effect on its financial position, results of operations and cash flows.

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● the costs and timing of regulatory approvals.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Going Concern – (continued)

The Company has based its estimates of funding requirements on assumptions that may prove to be wrong.

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As a result, the Company may have to significantly limit its operations and its business, financial condition and results of operations would be materially harmed.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Summary of Significant Accounting Policies

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Such estimates and assumptions impact, among others, the following:

the estimated useful lives for property and equipment, research and development costs, valuation of Goodwill and IPRD, contingent consideration, and impairment of long-lived assets.

the estimated useful lives for property and equipment, research and development costs, valuation of Goodwill and IPR&D, contingent consideration, and impairment of long-lived assets.

Making estimates requires management to exercise significant judgment.

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The Company considers this to be a normal business risk.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Summary of Significant Accounting Policies – (continued)

Property and Equipment

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As a result of this review, there was no impairment recognized for the years ended December 31, 2025 and 2024.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Summary of Significant Accounting Policies – (continued)

IPR&D assets represent the fair value assigned to technologies that the Company acquired, which at the time of acquisition have not reached technological feasibility and have no alternative future use.

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If the carrying amount exceeds the fair value, an impairment charge is recognized in an amount equal to that excess.

The key assumptions used to value IPR&D include estimates of future cash flows and to the discount rate applicable to the future cash flow periods.

The key assumptions used to value IPR&D include estimates of future cash flows and the discount rate applicable to the future cash flow periods.

There were no impairment charges recorded for the year ended December 31, 2025.

During the quarters ended June 30, 2024 and September 30, 2024, the Company experienced a sustained decline in the quoted market price of the Company’s Common Stock and the Company deemed this to be a triggering event for impairment.

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This interim analysis satisfied the requirements of the annual impairment test as the same information would be required for both measurement dates.

There were no impairment charges recorded for the year ended December 31, 2023.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Summary of Significant Accounting Policies – (continued)

Goodwill Impairment

The Company tests the carrying amounts of goodwill for recoverability on an annual basis on October 1 or more frequently if events or changes in circumstances indicate that the asset might be impaired.

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This interim analysis satisfied the requirements of the annual impairment test as the same information would be required for both measurement dates.

There were no impairment charges recorded for the year ended December 31, 2023.

Theriva Biologics, Inc.

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Diluted net loss per share assumes the issuance of potential dilutive common shares outstanding for the period and adjusts for any changes in income and the repurchase of common shares that would have occurred from the assumed issuance, unless such effect is anti-dilutive.

The number of shares of common stock underlying Series C and D Preferred shares convertible to common stock that were excluded from the computation of the net loss per common share for the year ended December 31, 2023 was 98,361 .

There were no shares of common stock underlying Series C and D Preferred shares excluded from the computation of net loss per common share for the year ended December 31, 2024, all were exercised in 2024.

The number of eligible options and warrants for the purchase of common stock that were excluded from the computations of net loss per common share for the year ended December 31, 2024 were 175,034 and 1,428,600 , respectively, and for the year ended December 31, 2023 were 175,049 and zero , respectively, because their effect is anti-dilutive.

Net loss attributable to common stockholders for the years ended December 31, 2025 and 2024 was $ 23.7 million and $ 25.7 million, respectively.

The number of eligible options and warrants for the purchase of Common Stock that were excluded from the computations of net loss per common share for the year ended December 31, 2025 were 1,114,428 and 16,339,060 , respectively, and for the year ended December 31, 2024 were 175,034 and 1,428,600 , respectively, because their effect is anti-dilutive.

Theriva Biologics, Inc.

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Accrued CRO costs are subject to revisions as such studies progress to completion.

At December 31, 2024 and 2023, the Company has accrued CRO expenses of $ 2.4 million and $ 1.7 million, respectively, that are included in accrued expenses.

As of December 31, 2024, and 2023, the Company has prepaid CRO costs of $ 365,000 and $ 1.1 million, respectively, that are included in prepaid expenses.

At December 31, 2025 and 2024, the Company has accrued CRO expenses of $ 842,000 and $ 2.4 million, respectively, that are included in accrued expenses.

As of December 31, 2025, and 2024, the Company has prepaid CRO costs of zero and $ 365,000 , respectively, that are included in prepaid expenses.

The Company assesses all contracts at inception to determine whether a lease exists.

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Stock Warrants

The Company’s Warrants are exercisable at any time and from time to time, in whole or in part, following the date of issuance and ending five years from the date of the execution of the Warrant Agreement.

The Company’s warrants are exercisable at any time and from time to time, in whole or in part, following the date of issuance and ending five years from the date of the execution of the applicable Warrant Agreement.

The warrants were measured at fair value at the date of issuance, which was recorded in additional paid-in capital as a reduction of the gross proceeds raised in the public offering.

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Summary of Significant Accounting Policies – (continued)

Preferred Stock

The Company’s Series C and D Preferred Stock is classified as temporary equity on the accompanying consolidated balance sheet in accordance with authoritative guidance for the classification and measurement of convertible securities.

Fair Value of Financial Instruments

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In connection with the Acquisition of VCN, the Company was required to pay up to $ 70.2 million in additional consideration upon the achievement of certain milestones, including regulatory filings.

In September 2022, the Company received approval from the FDA to proceed with the Phase 2 clinical trial of VCN-01 in PDAC.

In September 2022, the Company received approval from the FDA to proceed with the Phase 2 clinical trial of VCN-01 (zabilugene almadenorepvec) in PDAC.

Due to this approval the Company paid Grifols Innovation and New Technologies Limited (“Grifols”), $ 3.0 million in the fourth quarter 2022.

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As a result, payment was made subsequent to September 30, 2023 in the amount of $ 3.25 million.

During the year ended December 31, 2025, the Company met the primary survival and safety endpoints in its VIRAGE Phase 2b clinical trial evaluating the Company’s lead product candidate VCN-01.

As a result of achieving the primary survival and safety endpoints in the Phase 2b clinical trial, the Company is obligated to pay Grifols $ 6.0 million.

On August 5, 2025, the Company and Grifols agreed to defer the $ 6.0 million milestone payment into three payments, as follows:

$ 500,000 was paid in August 2025, $ 500,000 was paid in of December 2025, and the remaining $ 5.0 million payment will be deferred pending ongoing discussions with Grifols.

The discounted cash flow method used to value this contingent consideration includes inputs of not readily observable market data, which are Level 3 inputs.

The fair value of the contingent consideration was $ 10.0 million as of December 31, 2025 and is reflected as non-current contingent consideration liability.

There were no transfers in or out of the level 3 liabilities during the years ended December 31, 2024 and 2023.

During the year ended December 31, 2024 and 2023, the Company recognized in operating expense a $ 699,000 increase and $ 660,000 decrease, respectfully, fair value adjustment to contingent consideration.

During the years ended December 31, 2025 and 2024, the Company recognized in operating expense a $ 9.0 million increase and $ 699,000 increase, respectfully, fair value adjustment to contingent consideration.

There were no transfers in or out of the level 3 liabilities during the years ended December 31, 2025 and 2024, with the exception of the reclassification of $ 6.0 million related to the milestone that was met during the year ending December 31, 2025 and reclassified to accrued expenses.

Theriva Biologics, Inc.

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Balance at December 31, 2024

Payment of contingent consideration

Change in fair value

Reclassification of amounts to accrued expenses due to milestone being achieved

Balance at December 31, 2025

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5.3 % to 48.8

The Company measures certain non - financial assets on a non - recurring basis, including goodwill and in - process R&D.

The Company measures certain non - financial assets on a non - recurring basis, including goodwill and in - process R&D on an annual basis on October 1, or more frequently if the Company becomes aware of any events occurring or changes in circumstances that could indicate an impairment.

As a result of those measurements, during the year ended December 31, 2024 in - 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.

There were no impairment changes during the year ended December 31, 2025.

This analysis 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.

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The Company’s estimates of future cash flows are based on a comprehensive product by product forecast over a period which covers Phase 1 to approval and 15 years of commercialized revenue and involve assumptions concerning (i) future operating performance, including research and development costs through approval of the drug, the future addressable market, future sales, long - term growth rates, operating margins, allocation and timing of cash flows and the probability of achieving the estimated cash flows and (ii) future economic conditions, all which may differ from actual future cash flows.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Summary of Significant Accounting Policies – (continued)

Assumptions related to future operating performance are based on management’s annual and ongoing budgeting, forecasting and planning processes and represent the Company’s best estimate of the future results of its operations as of a point in time.

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The use of different inputs and assumptions could increase or decrease the Company’s estimated discounted future cash flows, the resulting estimated fair values and the amounts of related goodwill impairments, if any.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Summary of Significant Accounting Policies – (continued)

Stock-Based Payment Arrangements

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The Company’s chief operating decision maker (“CODM”) is the Company’s Chief Executive Officer.

The CODM is assisted in his responsibilities of making decisions regarding resource allocation and performance assessment by the leadership team, consisting of the General Director and Head of Corporate and Product Development.

The CODM is assisted in his responsibilities of making decisions regarding resource allocation and performance assessment by the leadership team, consisting of the Senior Vice President of Corporate and Product Development.

The Company views its operations and manages its business as one operating segment, focused on the discovery and development of oncolytic viruses intended to overcome the protective barrier surrounding solid tumors and selectively kill tumor cells.

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The Company monitors its cash and cash equivalents as reported on the Company’s Balance Sheets to determine funding for its research and development.

As the Company does not currently generate revenue, the CODM assesses Company performance through the achievement of pre-clinical and clinical research goals.

As the Company does not currently generate revenue, the CODM assesses Company performance using the consolidated net loss and through the achievement of pre-clinical and clinical research goals.

In addition to the Company’s Statement of Operations and Comprehensive Loss, the CODM is regularly provided with budgeted and forecasted expense information which is used to determine the Company’s liquidity needs and cash allocation.

The measure of segment assets is reported on the consolidated balance sheet as total consolidated assets.

The Company’s principal operations are in the United States and the Company’s long-lived assets are located primarily with in the United States and Spain.

The Company held $ 58,000 and $ 53,000 of assets in the United States on December 31, 2025 and 2024, respectively.

The Company held $ 164,000 and $ 216,000 of assets in the Spain on December 31, 2025 and 2024, respectively.

Foreign Currencies

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Translation adjustments are accumulated in a separate component of stockholders’ equity in the accompanying consolidated balance sheets.

Transaction gains and losses are classified as other income (expense) net in the accompanying consolidated statements of operations.

Transaction gains and losses are classified as other income (expense) net in the accompanying consolidated statements of operations and comprehensive loss.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Summary of Significant Accounting Policies – (continued)

The Company accounts for income taxes under the liability method;

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The second step is to measure the tax benefit as the largest amount that is more than 50% likely of being realized upon ultimate settlement.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Summary of Significant Accounting Policies – (continued)

Recent Accounting Pronouncements and Developments

In December 2025, the FASB issued ASU 2025-10, Accounting for Government Grants Received by Business Entities (ASU 2025-10), ASU 2025-10 establishes guidance on the recognition, measurement, and presentation of government grants received by business entities.

The new guidance leverages the principles in the accounting framework for government assistance in IFRS, specifically IAS 20, Accounting for Government Grants and Disclosure of Government Assistance;

makes certain targeted improvements;

and modifies certain of the existing disclosure requirements in ASC 832, Government Assistance.

The new guidance is effective for public business entities in annual periods beginning after December 15, 2028 (including interim periods within) and one year later for all other entities, with early adoption permitted in any period for which financial statements have not yet been issued.

The guidance can be applied on a modified prospective basis, a modified retrospective basis, or a full retrospective basis.

The Company is currently evaluating the potential impact of the guidance and potential additional disclosures required.

In December 2025, the FASB issued ASU 2025-11, Interim Reporting (Topic 270):

Narrow-Scope Improvements (“ASU 2025-11”).

ASU 2025-11 is intended to clarify and improve certain aspects of interim financial reporting, including the requirements for interim disclosures and the application of recognition and measurement guidance in interim periods.

ASU 2025-11 is effective for interim reporting periods within annual reporting periods beginning after December 15, 2026.

The Company is currently evaluating the potential impact of the guidance and potential additional disclosures required.

In November 2025, the FASB issued ASU 2025-09, Derivatives and Hedging (Topic 815):

Hedge Accounting Improvements (“ASU 2025-09”).

ASU 202509 expands eligibility of risk components for hedge designation, clarifies the presentation and disclosure requirements for hedging relationships, and simplifies the assessment of hedge effectiveness.

ASU 2025-09 is effective for annual periods beginning after December 15, 2026, including interim periods within those fiscal years.

The Company is currently evaluating the potential impact of the guidance and potential additional disclosures required.

On November 2024, the FASB issued ASU 2024-03 - Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40):

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For public business entities, the guidance is effective for annual periods beginning after December 15, 2024.

The Company is not early adopting this ASU, and therefore, this ASU is not adopted in the current period.

The Company does not expect this ASU to have a material impact on the consolidated financial statements.

In November 2023, the FASB issued ASU No.

2023-07, Segment Reporting (Topic 280):

Improvements to Reportable Segment Disclosures which requires public entities to disclose significant segment expenses regularly provided to the chief operating decision-maker.

Public entities with a single reporting segment have to provide all disclosures required by ASC 280, including the significant segment expense disclosures.

For public business entities, the guidance is effective for annual periods beginning after December 15, 2024.

The Company adopted this standard for the Company’s fiscal year 2024 annual reporting period.

Goodwill and Intangibles

The Company adopted the provisions of ASU 2023-09 for the annual period ending December 31, 2025.

See Income Taxes footnote 13.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

The following table provides the Company’s Goodwill as of December 31, 2024.

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Balance at December 31, 2024

Effects of exchange rates

Balance at December 31, 2025

On October 1, 2025, the Company performed its annual impairment test.

The impairment test consists of a comparison of the estimated fair value of the IPR&D with its carrying amount.

If the carrying amount exceeds the fair value, an impairment charge is recognized in an amount equal to that excess.

The key assumptions used to value IPR&D include estimates of future cash flows and the discount rate applicable to the future cash flow periods.

There were no impairment charges recorded during the year ended December 31, 2025.

The Company performed an interim impairment analysis using both the replacement cost method and 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.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Goodwill and Intangibles – (continued)

For the quarter ended June 30, 2024, the Company concluded that goodwill with a carrying value of $ 5.6 million was written down to its estimated fair value of $ 1.5 million and an impairment charge of $ 4.1 million was recorded during the quarter ended June 30, 2024.

For the quarter ended June 30, 2024, the Company concluded that goodwill with a carrying value of $ 5.6 million was written down to its estimated fair value of $ 1.5 million and an impairment charge $ 4.1 million was recorded during the quarter ended June 30, 2024.

For the quarter ended September 30, 2024 the Company concluded that goodwill with a carrying value of $ 1.5 million was impaired and was written down to its estimated fair value of zero and an impairment charge of $ 1.5 million was recorded.

This interim analysis satisfied the requirements of the annual impairment test as the same information would be required for both measurement dates.

There were no impairment charges recorded for the year ended December 31, 2023.

For the quarter ended June 30, 2024 the Company concluded that the IPR&D was not impaired however, for the quarter ended September 30, 2024, the Company concluded that the in-process R&D with a carrying value of $ 19.8 million was impaired and was written down to its estimated fair value of $ 18.6 million and an impairment charge of $ 1.3 million was recorded.

This interim analysis satisfied the requirements of the annual impairment test as the same information would be required for both measurement dates.

There were no impairment charges recorded for the year ended December 31, 2023.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Research and Development Tax Credits

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subsidiary, participates 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 the Company incurs in Spain.

The program provides for reimbursement of certain expenses incurred in research and development efforts the Company conducts in Spain.

The reimbursements can be through either tax credits or direct refunds.

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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, the Company completed the certification and applied for direct reimbursement, as opposed to a tax credit, for its qualifying research and development expenses incurred in the year ended December 31, 2022.

The Company received approvals from the Spanish government in September and October 2023.

During the quarter ended June 30, 2025, the Company completed the certification and applied for direct reimbursement for its qualifying research and development expenses incurred in the year ended December 31, 2024.

The Company received approvals from the Spanish government in November 2025.

During the quarter ended June 30, 2024, the Company completed the certification and applied for direct reimbursement for its qualifying research and development expenses incurred in the year ended December 31, 2023.

The Company received approvals from the Spanish government in December 2024.

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Additionally, the Company has elected to account for the tax credit as a contra-expense as this most appropriately reflects the nature of the transaction and will reduce future research and development expenditures as the Company continues to incur expenses in the upcoming 24-month period.

During the year ending December 31, 2024 the Company recorded $ 888,000 , as a reduction in research and development expense.

During the year ending December 31, 2025 and 2024 the Company recorded $ 1.8 million and $ 888,000 , respectively, as a reduction in research and development expense.

Theriva Biologics, Inc.

3 unchanged sentences

PREPAID EXPENSES AND OTHER CURRENT ASSETS (in thousands):

Prepaid manufacturing expenses

Stock sales receivable

Prepaid insurance

Prepaid clinical research organizations

Prepaid consulting, subscriptions and other expenses

VAT receivable

Prepaid manufacturing expenses

Prepaid clinical research organizations

Total prepaid expenses and other current assets

Prepaid clinical research organizations (CROs) expense is classified as a current asset.

Stock sales receivable is from at-the-market stock sales that have not cash settled prior to the period end.

Prepaid CROs expense is classified as a current asset.

The Company makes payments to the CROs based on agreed upon terms that include payments in advance of study services.

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During the years ended December 31, 2025 and 2024 the Company recognized depreciation expense of $ 108,000 and $ 137,000 respectively.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Selected Balance Sheet Information – (continued)

ACCRUED EXPENSES (in thousands)

Accrued milestones payments

Accrued clinical consulting services

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Total accrued employee benefits

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Stock-Based Compensation

Stock Incentive Plan

On November 2, 2010, the Board of Directors and stockholders adopted the 2010 Stock Incentive Plan (“2010 Stock Plan”) for the issuance of up to 343 shares of Common Stock to be granted through incentive stock options, nonqualified stock options, stock appreciation rights, dividend equivalent rights, restricted stock, restricted stock units and other stock-based awards to officers, other employees, directors and consultants of the Company and its subsidiaries.

From time to time the number of shares authorized for awards was increased such that 16,000 were authorized as of September 5, 2019.

On November 2, 2010, the Company’s Board of Directors and stockholders adopted the 2010 Stock Incentive Plan (“2010 Stock Plan”) for the issuance of up to 343 shares of Common Stock to be granted through incentive stock options, nonqualified stock options, stock appreciation rights, dividend equivalent rights, restricted stock, restricted stock units and other stock-based awards to officers, other employees, directors and consultants of the Company and its subsidiaries.

From time to time the number of shares authorized for awards was increased such that 16,000 shares were authorized as of September 5, 2019.

The exercise price of stock options under the 2010 Stock Plan was determined by the compensation committee of the Board of Directors and could be equal to or greater than the fair market value of the Company’s Common Stock on the date the option was granted.

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Only options were issued under the plan.

On September 17, 2020, the stockholders approved and adopted the 2020 Stock Incentive Plan ("2020 Stock Plan") for the issuance of up to 16,000 shares of Common Stock to be granted through incentive stock options, nonqualified stock options, stock appreciation rights, dividend equivalent rights, restricted stock, restricted stock units and other stock-based awards to officers, other employees, directors and consultants of the Company and its subsidiaries.

On September 17, 2020, the Company’s stockholders approved and adopted the 2020 Stock Incentive Plan (“2020 Stock Plan”) for the issuance of up to 16,000 shares of Common Stock to be granted through incentive stock options, nonqualified stock options, stock appreciation rights, dividend equivalent rights, restricted stock, restricted stock units and other stock-based awards to officers, other employees, directors and consultants of the Company and its subsidiaries.

The number of shares authorized for awards under the 2020 Stock Plan was increased such that 4,500,000 shares were authorized as of December 31, 2025.

1 unchanged sentence

Only options have been issued under the plan.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Stock-Based Compensation – (continued)

In the event of an employee’s termination, the Company will cease to recognize compensation expense for that employee.

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● monthly over three years.

During the years ended December 31, 2024 and 2023, the Company granted 420 and 87,800 , respectively, options to purchase shares of common stock to employees and directors having an approximate fair value of $ 1,500 and $ 0.9 million, respectively, based upon the Black-Scholes option pricing model, respectively.

During the years ended December 31, 2025 and 2024, the Company granted 951,500 and 420 , respectively, options to purchase shares of Common Stock to employees and directors having an approximate fair value of $ 1.0 million and $ 1,500 , respectively, based upon the Black-Scholes option pricing model, respectively.

Stock-based compensation expense included in general and administrative expenses and research and development expenses relating to stock options issued to employees for the years ended December 31, 2025 and 2024 was $ 517,000 and $ 462,000 , respectively.

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Stock-Based Compensation – (continued)

As of December 31, 2024, total unrecognized stock-based compensation expense related to stock options was $ 596,000 which is expected to be expensed through September 2026.

As of December 31, 2025, total unrecognized stock-based compensation expense related to stock options was $ 694,000 which is expected to be expensed through January 2028.

The FASB’s guidance for stock-based payments requires cash flows from excess tax benefits to be classified as a part of cash flows from operating activities.

3 unchanged sentences

Stock Warrants

On September 27, 2024, the Company consummated a public offering (the “Offering”) of an aggregate of (i) 918,600 shares (the “Shares”) of Common Stock, (ii) pre-funded warrants (“Pre-Funded Warrants”) to purchase up to 510,000 shares of Common Stock (the “Pre-Funded Warrant Shares”), and (iii) Common Stock purchase warrants (“Common Warrants”) to purchase up to 1,428,600 shares of Common Stock (the “Common Warrant Shares”).

Each Share and associated Common Warrant to purchase one (1) Common Warrant Share was sold at a combined public offering price of $ 1.75 .

Each Pre-Funded Warrant and associated Common Warrant to purchase one (1) Common Warrant Share was sold at a combined public offering price of $ 1.7499 .

On September 27, 2024, the Company consummated a public offering (the “2024 Offering”) of an aggregate of (i) 918,600 shares of Common Stock, (ii) pre-funded warrants (the “2024 Pre-Funded Warrants”) to purchase up to 510,000 shares of Common Stock (the “2024 Pre-Funded Warrant Shares”), and (iii) Common Stock purchase warrants (the “2024 Common Warrants”) to purchase up to 1,428,600 shares of Common Stock (the “Common Warrant Shares”).

Each Share and associated 2024 Common Warrant was sold at a combined public offering price of $ 1.75 .

Each 2024 Pre-Funded Warrant and associated 2024 Common Warrant was sold at a combined public offering price of $ 1.7499 .

The Company received aggregate gross proceeds from the 2024 Offering of approximately $ 2.5 million, before deducting placement agent fees and other offering expenses.

The Company intends to use the proceeds of the Offering primarily for working capital and general corporate purposes, including research and development and manufacturing scale-up and may use a portion of the proceeds to invest in or acquire other products, businesses or technologies.

Each Pre-Funded Warrant was immediately exercisable for one (1) Pre-Funded Warrant Shares at an exercise price of $ 0.0001 per share and was to remain exercisable until the Pre-Funded Warrants are exercised in full.

Each Common Warrant has an exercise price of $ 2.00 per share, is immediately exercisable for one (1) Common Warrant Share, and expires five (5) years from its issuance date.

The Shares, Pre-Funded Warrants and accompanying Common Warrants were issued separately.

Each 2024 Pre-Funded Warrant was immediately exercisable for one share of Common Stock at an exercise price of $ 0.0001 per share and was to remain exercisable until the 2024 Pre-Funded Warrants are exercised in full.

Each 2024 Common Warrant has an exercise price of $ 2.00 per share, is immediately exercisable for one (1) share of Common Stock, and expires five (5) years from its issuance date.

The shares of Common Stock, 2024 Pre-Funded Warrants and accompanying 2024 Common Warrants were issued separately.

The exercise price of the 2024 Common Warrants and the 2024 Pre-Funded Warrants and number of shares of Common Stock issuable upon exercise will adjust in the event of certain stock dividends and distributions, stock splits, stock combinations, reclassifications or similar events.

The Common Warrants may be exercised on a cashless basis if at the time of exercise thereof there is no effective registration statement registering, or the prospectus contained therein is not available for, the issuance of the Common Warrant Shares to the holder.

The 2024 Common Warrants may be exercised on a cashless basis if at the time of exercise thereof there is no effective registration statement registering, or the prospectus contained therein is not available for, the issuance of the Common Stock issuable upon exercise of the 2024 Common Warrants to the holder.

The 2024 Pre-Funded Warrants could be exercised on a cashless basis at any time.

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The 2024 Common Warrants were valued on the date of grant using Black Scholes model.

During the year ended December 31, there were zero Common Warrants exercised and as of December 31, 2024, 510,000 Pre-Funded warrants were exercised.

During the year ended December 31, 2024, there were zero 2024 Common Warrants exercised and as of December 31, 2024, all 510,000 2024 Pre-Funded warrants were exercised.

During the year ended December 31, 2025 there were 1,345,000 2024 Common Warrants exercised in the October 17, 2025 warrant inducement.

Theriva Biologics, Inc.

2 unchanged sentences

Stock Warrants – (continued)

On October 15, 2018, the Company closed its underwritten public offering pursuant to which it received gross proceeds of approximately $ 18.6 million before deducting underwriting discounts, commissions and other offering expenses payable by the Company and sold (i) Class A Units (the “Class A Units”), consisting of an aggregate of 252,000 shares of the Common Stock, warrants to purchase an aggregate of 252,000 shares of Common Stock at an exercise price of $ 13.80 per share, which subsequently was reduced to $ 6.90 per share and then again to $ 1.22 (each a “Warrant” and collectively, the “Warrants”) and (ii) Class B Units (the “Class B Units”, and together with the Class A Units, the “Units”), consisting of an aggregate of 15,723 shares of the Company’s Series B Convertible Preferred Stock (the “Series B Preferred Stock”), with a stated value of $ 1,000 and convertible into shares of Common Stock at the stated value divided by a conversion price of $ 11.50 per share, with all shares of Series B Preferred Stock convertible into an aggregate of 1,367,218 shares of Common Stock, and issued with a warrant to purchase an aggregate of 1,367,218 shares of Common Stock.

The Warrants were valued on the date of grant using Monte Carlo simulations.

There were no Warrants exercised during the year ended December 31, 2023.

The Warrants expired in October 2023 and are no longer outstanding.

Upon expiration, the balance in additional paid - in capital related to the warrants was transferred to the additional paid - in capital balance related to Common Stock with no effect on additional paid - in capital.

On May 8, 2025 the Company consummated a public offering (the “May 2025 Offering”) of an aggregate of (i) 1,990,900 shares of Common Stock, (ii) pre-funded warrants (the “2025 Pre-Funded Warrants”) to purchase up to 4,827,280 shares of common stock (the “2025 Pre-Funded Warrant Shares”), and (iii) Common Stock purchase warrants (the “2025 Common Warrants”) to purchase up to 6,818,180 shares of common stock (the “2025 Common Warrant Shares”).

Each share of Common Stock and associated 2025 Common Warrant was sold at a combined public offering price of $ 1.10 .

Each 2025 Pre-Funded Warrant and associated 2025 Common Warrant was sold at a combined public offering price of $ 1.099 .

The Company received aggregate gross proceeds from the May 2025 Offering of approximately $ 7.5 million, before deducting placement agent fees and other offering expenses.

Each 2025 Pre-Funded Warrant was immediately exercisable for one (1) share of Common Stock at an exercise price of $ 0.001 per share and will remain exercisable until such 2025 Pre-Funded Warrant is exercised in full.

Each 2025 Common Warrant has an exercise price of $ 1.10 per share of Common Stock, is immediately exercisable, and expires five (5) years from its issuance date.

The exercise price of the 2025 Common Warrants and the 2025 Pre-Funded Warrants and number of shares of common stock issuable upon exercise will be adjusted in the event of certain stock dividends and distributions, stock splits, stock combinations, reclassifications or similar events.

In the event of a fundamental transaction, as described in each of the 2025 Common Warrants and the 2025 Pre-Funded Warrants, the holders of such warrants will be entitled to receive upon exercise of their respective warrants the kind and amount of securities, cash or other property that the holders would have received had they exercised their warrants immediately prior to such fundamental transaction.

In addition, in certain circumstances, upon a fundamental transaction, a holder of 2025 Common Warrants will have the right to require us to repurchase its 2025 Common Warrants at the Black Scholes Value;

provided, however, that, if the fundamental transaction is not within the Company’s control, including not approved by the Company’s board of directors, then the holder shall only be entitled to receive the same type or form of consideration (and in the same proportion), at the Black Scholes Value of the unexercised portion of the 2025 Common Warrant, that is being offered and paid to the holders of common stock in connection with the fundamental transaction.

The 2025 Common Warrants may be exercised on a cashless basis if at the time of exercise thereof there is no effective registration statement registering, or the prospectus contained therein is not available for, the issuance of the share of Common Stock issuable upon exercise thereof to the holder.

The 2025 Pre-Funded Warrants may be exercised on a cashless basis at any time.

A holder of the 2025 Common Warrants and the 2025 Pre-Funded Warrants (together with its affiliates) may not exercise any portion of the 2025 Common Warrant or 2025 Pre-Funded Warrant to the extent that the holder would own more than 4.99 % (or 9.99 %, at the election of the holder) of the outstanding shares of Common Stock immediately after exercise, except that upon at least 61 days ’ prior notice from the holder to the Company, the holder may increase the amount of beneficial ownership of outstanding shares after exercising the holder’s 2025 Common Warrants or 2025 Pre-Funded Warrants up to 9.99 % of the number of the Company’s shares of common stock outstanding immediately after giving effect to the exercise.

The Company has concluded that the 2025 Common Warrants and 2025 Pre-Funded Warrants are required to be equity classified.

The 2025 Common Warrants were valued on the date of grant using Black Scholes model.

During the year ended December 31, 2025, all 4,827,280 2025 Pre-Funded Warrants issued in the May 2025 Offering were exercised.

During the year ended December 31, 2025 there were 6,747,280 2025 Common Warrants exercised with the October 17, 2025 warrant inducement.

On October 16, 2025, the Company entered into a warrant inducement agreement (the “Inducement Agreement”) with certain holders named therein (the “Holders”) of existing Common Stock Purchase Warrants to purchase up to an aggregate of 8,092,280 shares of the Company’s common stock, consisting of (i) Common Stock Purchase Warrants to purchase up to an aggregate of 1,345,000 shares of common stock issued on September 27, 2024 (the “September Warrants”) and (ii) Common Stock Purchase Warrants to purchase up to an aggregate of 6,747,280 shares of common stock issued on May 8, 2025 (the “May Warrants” and, together with the September Warrants, the “Existing Warrants”).

Pursuant to the Inducement Agreement, on October 17, 2025, the Holders exercised for cash the Existing Warrants at a reduced exercise price of $ 0.54 per share and, in consideration therefor, the Company issued to the Holders new Common Stock Purchase Warrants (the “New Warrants”) to purchase an aggregate of 16,184,560 shares of common stock, equal to 200 % of the number of shares of Common Stock underlying the Existing Warrants, at an exercise price of $ 0.54 per share, which New Warrants are exercisable for a term of five (5) years from the date of the approval from the stockholders of the Company of the full exercise of the New Warrants and the issuance of all of the shares of common stock issuable upon the exercise thereof, which had not occurred as of December 31, 2025.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Stock Warrants – (continued)

The Company received aggregate gross proceeds of approximately $ 4.4 million for the exercise of the Existing Warrants, before deducting placement agent fees of $ 356,000 and other expenses of $ 72,000 payable by the Company.

AGP served as the Company’s exclusive financial advisor in connection with the warrant exercise and other transactions described in the Inducement Agreement.

Pursuant to the terms of an engagement letter, dated October 16, 2025, by and between the Company and AGP, the Company agreed to pay to AGP a cash fee equal to 7.0 % of the aggregate gross proceeds received from the Holder upon exercise of the Existing Warrants and reimbursement of certain expenses.

The Company evaluated the facts and circumstances of the inducement transaction and concluded that the issuance of the new warrants, issued to induce the existing warrant holders to exercise their original warrants, was directly attributable to an equity issuance.

Accordingly, the Company recognized the increase in value transferred to the holders as an equity issuance cost.

The increase in value transferred to holders was measured as the difference between the fair value of the new warrants and the fair value of the original warrants at the modification date, totaling $ 5.9 million.

The increased value provided by the modification and the issuance of new warrants in excess of the gross proceeds of $ 1.5 million was accounted for as a deemed dividend and increased net loss available to common shareholders for purposes of calculating loss per share.

The Company determined the fair value of the new warrants and original warrants on the modification date through the use of a Black Scholes model.

The increase in value transferred to the holders was recognized as a decrease to additional paid in capital, which offset the recording of the new warrants, thereby resulting in no net impact to total equity.

A summary of all warrant activity for the Company for the year ended December 31, 2025 and the year ended December 31, 2024 is as follows:

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Balance at December 31, 2024

( 12,919,560 )

Balance at December 31, 2025

6 unchanged sentences

(the “Securities Purchase Agreement”), pursuant to which the Company issued and sold 275,000 shares of the Company’s Series C Convertible Preferred Stock, par value $ 0.001 per share (the “Series C Preferred Stock”), and 100,000 shares of the Company’s Series D Convertible Preferred Stock, par value $ 0.001 per share (the “Series D Preferred Stock,” and together with the Series C Preferred Stock, the “Preferred Stock”), at an offering price of $ 8.00 per share, for gross proceeds of approximately $ 3.0 million in the aggregate, before the deduction of discounts, fees and offering expenses.

The shares of Preferred Stock are convertible, at a conversion price (the "Conversion Price") of $ 1.22 per share (subject in certain circumstances to adjustments), into an aggregate of 2,459,016 shares of the Company's Common Stock, at the option of the holders of the Preferred Stock and, in certain circumstances, by the Company.

The Securities Purchase Agreement contains customary representations, warranties and agreements by the Company and customary conditions to closing.

The Company included certain proposals at its 2022 annual meeting of stockholders, including (i) an amendment to the Company’s Articles of Incorporation, as amended (the “Charter”), to change the name of the Company to “Theriva Biologics, Inc.” (the “Name Change”), (ii) an amendment to the Articles of Incorporation, as amended to increase the number of authorized shares of Common Stock from 20,000,000 to 350,000,000 (the “Authorized Common Stock Increase”) and (iii) to adjourn any meeting of stockholders called for the purpose of voting on the Authorized Common Stock Increase (collectively, the “Stockholder Items”).

The shares of Preferred Stock were convertible, at a conversion price (the “Conversion Price”) of $ 1.22 per share (subject in certain circumstances to adjustments), into an aggregate of 2,459,016 shares of the Company’s common stock, at the option of the holders of the Preferred Stock and, in certain circumstances, by the Company.

The Securities Purchase Agreement contained customary representations, warranties and agreements by the Company and customary conditions to closing.

The Company included certain proposals at its 2022 annual meeting of stockholders, including (i) an amendment to the Company’s Articles of Incorporation, as amended (the “Charter”), to change the name of the Company to “Theriva Biologics, Inc.” (the “Name Change”), (ii) an amendment to the Charter to increase the number of authorized shares of common stock from 20,000,000 to 350,000,000 (the “Authorized Common Stock Increase”) and (iii) to adjourn any meeting of stockholders called for the purpose of voting on the Authorized Common Stock Increase (collectively, the “Stockholder Items”).

The purchaser of the Preferred Stock agreed in the Purchase Agreement to (i) not transfer, offer, sell, contract to sell, hypothecate, pledge or otherwise dispose of the shares of the Preferred Stock until the earlier of the date that the Authorized Common Stock Increase being proposed at the 2022 annual meeting of stockholders was effected or October 26, 2022 and (ii) vote the shares of the Series C Preferred Stock purchased in the Offering in favor of the Stockholder Items.

The authorized increase was effected prior to October 26, 2022.

The Authorized Common Stock Increase was effected on October 26, 2022.

Pursuant to the Securities Purchase Agreement, the Company filed certificates of designation (the “Certificates of Designation”) with the Secretary of the State of Nevada designating the rights, preferences and limitations of the shares of Series C Preferred Stock and Series D Preferred Stock.

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The Series C Preferred Stock and Series D Preferred Stock were classified as temporary equity as a result of the deemed liquidation provision.

Transaction expenses paid to third parties will be charged to temporary equity and will not be accreted as deemed dividends until redemption becomes probable.

During year ending December 31, 2024, the Company issued 72,132 shares of its Common Stock upon the conversion effected by the holder of the Series C Preferred of 275,000 shares of its Series C convertible Preferred Stock at a conversion price of $ 30.50 per share.

Transaction expenses paid to third parties were charged to temporary equity and were not to be accreted as deemed dividends until redemption becomes probable.

During year ending December 31, 2024, the Company issued 72,132 shares of its Common Stock upon the conversion effected by the holder of the Series C Preferred Stock of 275,000 shares of its Series C Preferred Stock at a conversion price of $ 30.50 per share.

As a result of the conversions during the year ending December 31, 2024, the Company reduced the Series C Preferred Stock $ 2.0 million and Additional Paid in Capital $ 2.0 million.

4 unchanged sentences

Stockholders’ Equity – (continued)

During year ending December 31, 2024, the Company issued 26,230 shares of its Common Stock upon the conversion effected by the holder of the Series D Preferred of 100,000 shares of its Series D convertible Preferred Stock at a conversion price of $ 30.50 per share.

As a result of the conversion during the year ending December 31, 2024 the Company reduced the Series D Preferred Stock $ 728,000 and Additional Paid in Capital $ 728,000 .

During year ending December 31, 2024, the Company issued 26,230 shares of its Common Stock upon the conversion effected by the holder of the Series D Preferred Stock of 100,000 shares of its Series D Preferred Stock at a conversion price of $ 30.50 per share.

As a result of the conversion during the year ending December 31, 2024 the Company reduced the Series D Preferred Stock to $ 728,000 and Additional Paid in Capital $ 728,000 .

There are no shares of Series D Preferred Stock outstanding as of December 31, 2025.

At Market Issuance Sales Agreement

On May 2, 2024, the Company and A.G.P./Alliance Global Partners (“AGP”) entered into Amendment No.

2 (“Amendment No.

2”) to that certain Amended and Restated Sales Agreement among the Company, AGP and FBR Capital Markets & Co.

(now known as B.

Riley Securities) dated as of February 9, 2021, as amended by Amendment No.

1 thereto dated May 3, 2021 (the “Sales Agreement”), pursuant to which the Company may offer and sell, from time to time, at its option, shares of the Common Stock through A.G.P./Alliance Global Partners, as sales agent, in an “at the market offering” as defined in Rule 415(a)(4) under the Securities Act of 1933, as amended (the “Securities Act”).

Sales in the “at the market offering” may occur under the Company’s current effective registration statement on Form S-3 which was filed on May 2, 2024 (File No.

333-279077) and declared effective on September 25, 2024.

On May 2, 2024, the Company and A.G.P./Alliance Global Partners (“A.G.P”) entered into the ATM Sales Agreement, pursuant to which the Company may offer and sell, from time to time, at its option, shares of the Common Stock through A.G.P, as sales agent, in an “at the market offering” as defined in Rule 415(a)(4) under the Securities Act of 1933, as amended (the “Securities Act”).

Sales in the “at the market offering” may occur under the Company’s current effective registration statement on Form S-3 (File No.

333 - 255726) which was filed on May 2, 2024 (File No.

333-279077) and declared effective on September 25, 2024, utilizing a prior prospectus and related prospectus supplements thereto or a newly filed registration statement on Form S - 3.

In addition, on May 1, 2024, the Company and B.

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Riley Securities, Inc.

would no longer be a party to the Sales Agreement.

During the year ended December 31, 2024, the Company sold through the Sales Agreement approximately 569,000 shares of the Company’s Common Stock and received net proceeds of approximately$ 3.6 million, respectively.

During the year ended December 31, 2023, the Company sold through the At Market Issuance Sales Agreement and the Amended and Restated Sales Agreement approximately 81,000 shares of the Company’s Common Stock and received net proceeds of approximately $ 2.2 million.

would no longer be a party to the ATM Sales Agreement.

During the year ended December 31, 2025, the Company sold through the Sales Agreement 17,998,117 shares of the Company’s Common Stock pursuant to the ATM Sales Agreement and received net proceeds of approximately $ 6.8 million.

During the year ended December 31, 2024, the Company sold through the Sales Agreement approximately 569,000 shares of the Company’s Common Stock pursuant to the ATM Sales Agreement and received net proceeds of approximately $ 3.6 million.

Loans payable

As a result of the acquisition of VCN the Company acquired interest-free or below-market interest rates loans ( 0 %- 1 %) extended by Spanish governmental institutions of Ministerio de Ciencia, Innovacion y Universidades and ACC10 Generalitat de Catalunya (CDIT loans).

As a result of the Acquisition of VCN, the Company acquired interest-free or below-market interest rate loans ( 0 %- 1 %) extended by Spanish governmental institutions of Ministerio de Ciencia, Innovacion y Universidades (RETOS loan) and ACC10 Generalitat de Catalunya (NEBT loan).

The maturities of these loans are between 2024 and 2028.

As a result of the VCN Acquisition, the Company maintains a restricted cash collateral account of $ 96,000 relating to the RETOS loan, which is reflected as a non-current asset on the balance sheet.

As a result of the Acquisition, the Company maintains a restricted cash collateral account of $ 46,000 relating to the RETOS loan, which is reflected as a non-current asset on the balance sheet.

During September 2024, the Company announced that its THERICEL project had been awarded € 2.28 million (approximately $ 2.54 million) from the National Knowledge Transfer Program of the Spanish government’s Ministry of Science, Innovation & Universities to support a collaboration between the Company and the Universitat Autònoma de Barcelona (“UAB”) to advance the Company’s THERICEL suspension cell platform for the clinical manufacture of adenovirus- and adeno-associated virus (“AAV”) therapies.

Under the award, the Company (via its wholly owned subsidiary, Theriva Biologics SL) received an unsecured loan (the “Loan”) of € 1.3 million (approximately $ 1.4 million) as a lump sum payment on January 17, 2025 which bears interest at a rate of 4.015 % and is to be repaid over 7 years commencing three years from the date of award.

The Company incurred and charged to interest expense $ 61,000 and $ 6,000 during the years ended December 31, 2025 and 2024, respectively.

The current and non-current balance of outstanding loans as of December 31, 2025 and 2024 was as follows (amounts in thousands of dollars) :

December 31, 2025

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December 31, 2024

THERICEL Loan

Theriva Biologics, Inc.

4 unchanged sentences

Related Party

On December 14, 2023 the Company approved the retention of MaryAnn Shallcross, the wife of Steven Shallcross, as director of Clinical Operations, for compensation of $ 152,000 , a bonus of $ 70,000 and the grant of an option to purchase 3,000 shares of common stock having a value of $ 30,000 .

During the year ended December 31, 2023, Ms.

Shallcross had $ 145,000 in compensation expense.

On December 13, 2024 the Company approved the compensation of MaryAnn Shallcross of $ 157,000 and a bonus of $ 45,000 .

On December 13, 2024, the Company approved the compensation of MaryAnn Shallcross, the wife of Steven Shallcross, of $ 157,000 , a bonus of $ 45,000 .

During the year ended December 31, 2025, the Company had $ 202,000 in compensation expense related to Ms.

Shallcross and the grant of an option to purchase 25,000 shares of Common Stock having a value of $ 27,000 .

Shallcross was one of the seven employees whose employment was terminated in connection with the Company’s workforce reduction announced on September 30, 2025.

License, Collaborative and Employment Agreements and Commitments

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Due to the long-range nature of such commercial milestone liability amounts, they are neither probable at this time nor predictable and consequently are not recorded in the financial statements or included in this disclosure.

IDIBELL Technology Transfer Agreement

On August 31, 2010, VCN entered into a Technology Transfer Agreement (the “Technology Transfer Agreement”) with the Bellvitge Biomedical Research Institute (“IDIBELL”) for the exclusive license of the right to use a Spanish patent number P200901201 titled “Oncolytic adenoviruses for treating cancer” which is co-owned by IDIBELL and Catalan Oncology Institute (“ICO”) for the term of the patent.

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ICO Marketing License

On May 16, 2009, VCN entered into a Contract to Grant a Marketing License (the “ICO License Agreement”) with the Catalan Institute of Oncology (the “ICO”) for a manufacturing and marketing license of a patent P200700665 titled “Adenovirus with mutations in the area of endoplasmic retention of protein E3-19k and their use in the treatment of cancer” in connection with a sublicense identified therein.

On May 16, 2009, VCN entered into a Contract to Grant a Marketing License (the “ICO License Agreement”) with ICO for a manufacturing and marketing license of a patent P200700665 titled “Adenovirus with mutations in the area of endoplasmic retention of protein E3-19k and their use in the treatment of cancer” in connection with a sublicense identified therein.

The validity period of the license granted is unlimited with the only applicable limit being the patent’s own validity.

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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 ICO License terminates upon the expiration of the patent rights and is subject to early termination by either party in the event of a breach by the other party of its obligations thereunder.

The ICO License Agreement terminates upon the expiration of the patent rights and is subject to early termination by either party in the event of a breach by the other party of its obligations thereunder.

No amounts were incurred in 2025 and 2024.

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Sant Joan De Déu Collaboration and License Agreement

On February 15, 2016, VCN entered into a Collaboration Agreement to Conduct a Clinical Trial and Grant an Operating License (the “Collaboration and License Agreement”) with the Sant Joan De Déu Hospital (the “Hospital”) and the Sant Joan De Déu Foundation (the “Foundation”, and together with the Hospital, the “Institution”) regarding the conduct of a clinical trial to evaluate the safety and activity of VCN-01 in patients with refractory retinoblastoma.

The Collaboration and License Agreement provides that if the trial results are positive and VCN is interested in continuing with the development of VCN-01 for the treatment of retinoblastoma;

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The Collaboration and License Agreement continues in force and effect until all obligations arising from the trial have been fulfilled, subject to early termination for a material breach by a party of any of their contractual and/or legal obligations, or, in the case of any other type of breach, when the breaching party has been asked in writing to remedy the breach and the breach is not cured within thirty (30) days from the date on which the written request was sent.

On April 23, 2024, the Company announced positive topline data from this study, with agreement by the study Monitoring Committee that the study had a positive outcome.

Per the terms of the clinical trial agreement, the determination by the study Monitoring Committee that the study had a positive outcome means we received an exclusive, worldwide technology license, and related patents from Hospital Sant Joan de Déu for the treatment of pediatric patients with advanced retinoblastoma and we are obligated to pay to Hospital Sant Joan de Déu the amount of three hundred twenty thousand, two hundred and sixty five Euros (€ 320,265 ) or approximately $ 334,000 , half of which was paid during the year ended December 31, 2024 and the remaining half is expected to be paid upon invoice receipt.

On November 2, 2023, after Sant Joan de Déu - Barcelona Children’s Hospital determined that the trial results were positive, VCN and Sant Joan de Déu-Barcelona Children’s Hospital announced an agreement for an exclusive worldwide option to negotiate an exclusive license of certain Sant Joan de Deu intellectual property rights related to the use of VCN-01 in combination with topoisomerase I inhibitor chemotherapies for the treatment of cancer.

During the year ended December 31, 2023 the Company paid a Euros (€ 25,000 ) option fee.

During the year ended December 31, 2023 the Company paid Euros (€ 25,000 ) option fee.

During the year ended December 31, 2024 the Company paid Euros (€ 5,000 ) for a renewal of the option fee.

No amounts were incurred in 2025.

Washington University School of Medicine in St.

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The Company has the right to terminate the CTA (i) effective immediately if Washington University fails to perform the study in accordance with the terms of the protocol, the CTA or applicable laws or regulations or if Washington University or the principal investigator become debarred or (ii) upon 14 days written notice and Washington University has the right to terminate the CTA upon 14 days notice if the principal investigator becomes unable to perform or complete the Study and the parties have not, prior to the expiration of such fourteen (14) day period, agreed to an alternative principal investigator.

The Company paid $ 1.1 million related to this agreement during the year ended 2022.

There we no payments during 2024 or 2025.

Massachusetts General Hospital Exclusive Option License Agreement

On May 27, 2020, the Company entered into an agreement with Massachusetts General Hospital (“MGH”) granting us an option for an exclusive license to intellectual property and technology related to the use of intestinal alkaline phosphatase (“IAP”) to maintain gastrointestinal (GI) and microbiome health, diminish systemic inflammation, and treat age-related diseases.

If executed, the Company plans to use this license in the advancement of an expanded clinical development program for SYN-020, its proprietary recombinant version of bovine IAP currently in pre-clinical development.

Under the terms of the agreement, the Company is granted exclusive rights to negotiate a worldwide license with MGH to commercially develop SYN-020 to treat and prevent metabolic and inflammatory diseases associated with aging.

During the second quarter of 2021, the Company announced an amendment to its option for an exclusive license agreement with MGH to include intellectual property and technology related to the use of SYN-020 to inhibit liver fibrosis in select diseases, including NAFLD.

In January 2023, the Company paid $ 7,500 to extend the option period until July 2024 but elected to not extend the option thereafter.

University of Texas Austin Agreement

On December 19, 2012, the Company entered into a License Agreement with University of Texas Austin (“UT”) for the exclusive license of the right to use, develop, manufacture, market and commercialize certain research and patents related to pertussis antibodies.

The License Agreement provides that UT Austin is entitled to payment of past patent expenses, an annual payment of $ 50,000 per year commencing on the effective date through December 31, 2014, a $ 25,000 payment on December 31, 2015 and milestone payments of $ 50,000 upon commencement of Phase 1 clinical trials, $ 100,000 upon commencement of Phase 3 clinical trials, $ 250,000 upon NDA submission in the U.S., $ 100,000 upon European Medicines Agency approval and $ 100,000 upon regulatory approval in an Asian country.

In addition, UT Austin is entitled to a running royalty upon net sales.

The License Agreement terminates upon the expiration of the patent rights;

provided, however that the License Agreement is subject to early termination by the Company in its discretion and by UT Austin for a breach of the License Agreement by the Company.

No amounts were incurred in 2024 and 2023.

In connection with the License Agreement, the Company and UT Austin also entered into a Sponsored Research Agreement pursuant to which UT Austin will perform certain research work related to pertussis.

The Sponsored Research Agreement may be renewed annually, in the sole discretion of the Company, after the first year for two additional one year terms with a fixed fee for the first year of $ 303,000 .

The Sponsored Research Agreement was renewed for the second and third years for a fixed fee of $ 316,000 and $ 329,000 respectively, all payable in quarterly installments.

The Sponsored Research Agreement expired January 17, 2023.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

License, Collaborative and Employment Agreements and Commitments – (continued)

Prev ABR LLC (“Prev”) Agreement

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Employment Agreements

On January 3, 2022, the Company entered into a three-year employment agreement with Steven A.

On March 3, 2025, the Company entered into a two-year employment agreement with Steven A.

Shallcross, (the “2025 Shallcross Employment Agreement”), to serve as the Chief Executive Officer and to continue to serve as the Chief Financial Officer of the Company.

The Employment Agreement had a stated term of three years and expired on January 2, 2025;

Shallcross continued thereafter to serve as the Chief Executive Officer and continued to serve as the Chief Financial Officer of the Company thereafter.

A new agreement was signed on March 3, 2025.

See Subsequent Events.

On December 15, 2022, the Board of Directors of the Company awarded Steven A.

(i) a cash bonus equal to $ 385,000 , and (ii) an option to purchase 475,000 shares of the Company's common stock.

In addition, on December 15, 2022, the Company entered into an Amendment to Mr.

Shallcross's Employment Agreement to increase his base salary to $ 614,250 .

On December 14, 2023, the Board of Directors of the Company awarded Steven A.

(i) a cash bonus equal to $ 350,000 , and (ii) an option to purchase 700,000 shares of the Company's common stock.

In addition, on December 14, 2023, the Company increased his base salary to $ 644,963 due to a merit increase.

The 2025 Shallcross Employment Agreement has a stated term of two years but may be terminated earlier pursuant to its terms.

The terms of the 2025 Shallcross Employment Agreement were substantially the same as the terms of the employment agreement previously entered into by and between the Company and Mr.

Shallcross on January 3, 2022 except for the stated term.

Shallcross’ employment is terminated for any reason, he or his estate as the case may be, will be entitled to receive the accrued base salary, vacation pay, expense reimbursement and any other entitlements accrued by him to the extent not previously paid (the “Accrued Obligations”);

provided, however, that if his employment is terminated (i) by the Company without Cause or by Mr.

Shallcross for Good Reason (as each is defined in the 2025 Shallcross Employment Agreement) then in addition to paying the Accrued Obligations, (a) the Company will continue to pay his then current base salary and continue to provide benefits at least equal to those that were provided at the time of termination for a period of twelve (12) months and (b) he shall have the right to exercise any vested equity awards until the earlier of six (6) months after termination or the remaining term of the awards;

or (ii) by reason of his death or Disability (as defined in the 2025 Shallcross Employment Agreement), then in addition to paying the Accrued Obligations, Mr.

Shallcross would have the right to exercise any vested options until the earlier of six (6) months after termination or the remaining term of the awards.

In such event, if Mr.

Shallcross commenced employment with another employer and becomes eligible to receive medical or other welfare benefits under another employer-provided plan, the medical and other welfare benefits to be provided by the Company as described herein would terminate.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

License, Collaborative and Employment Agreements and Commitments – (continued)

The 2025 Shallcross Employment Agreement provides that upon the closing of a “Change in Control” (as defined in the 2025 Shallcross Employment Agreements), all unvested options shall immediately vest and the time period that Mr.

Shallcross will have to exercise all vested stock options and other awards that Mr.

Shallcross may have will be equal to the shorter of:

(i) eighteen (18) months after termination, or (ii) the remaining term of the award(s).

If within one (1) year after the occurrence of a Change in Control, Mr.

Shallcross terminates his employment for “Good Reason” or we terminate Mr.

Shallcross’s employment for any reason other than death, disability or Cause, Mr.

Shallcross will be entitled to receive:

(i) the portion of his base salary for periods prior to the effective date of termination accrued but unpaid (if any);

(ii) all unreimbursed expenses (if any);

(iii) an aggregate amount (the “Change in Control Severance Amount”) equal to two (2) times the sum of his base salary plus an amount equal to the bonus that would be payable if the “target” level performance were achieved under the Company’s annual bonus plan (if any) in respect of the fiscal year during which the termination occurs (or the prior fiscal year if bonus levels have not yet been established for the year of termination) subject to him executing a general release in form acceptable to us that becomes effective.

If within two (2) years after the occurrence of a Change in Control, Mr.

Shallcross terminates his employment for “Good Reason” or the Company terminates Mr.

Shallcross’s employment for any reason other than death, disability or Cause, Mr.

Shallcross will be entitled to also receive for the period of two (2) consecutive years commencing on the date of such termination of his employment, medical, dental, life and disability insurance coverage for him and the members of his family that are not less favorable to him than the group medical, dental, life and disability insurance coverage carried by the Company for him subject to him executing a general release in form acceptable to the Company that becomes effective.

The Change in Control Severance Amount is to be paid in a lump sum if the Change in Control event constitutes a “change in the ownership” or a “change in the effective control” of the Company or a “change in the ownership of a substantial portion of a corporation’s assets” (each within the meaning of Section 409A of the Internal Revenue Code (“Rule 409A”)), or in 48 substantially equal payments, if the Change in Control event does not so comply with Section 409A.

On December 13, 2024, the Board of Directors of the Company awarded Steven A.

1 unchanged sentence

In addition, on December 14, 2023, the Company increased his base salary to $ 667,536 due to a merit increase.

On April 28, 2025, Mr.

Shallcross was awarded options to purchase 190,000 shares of the Company’s Common Stock.

Operating Lease

9 unchanged sentences

The Company also leases research and office facilities in Barcelona, Spain for its 100 percent owned Theriva S.L.

The lease that was in existence from December 2021 to December 2022 was a short term agreement with a 90-day termination notice provision that can be exercised by either party.

On the closing date of the Acquisition, a sublease was executed for Theriva S.L.

3 unchanged sentences

moved into the facilities and the new lease commenced and the prior lease terminated.

Operating lease costs are presented as part of general and administrative expenses in the condensed consolidated statements of operations, and for the year ended December 31, 2024 and 2023 approximated $ 631,000 and $ 624,000 , respectively.

Operating lease costs are presented as part of general and administrative expenses in the consolidated statements of operations, and for the year ended December 31, 2025 and 2024 approximated $ 656,000 and $ 631,000 , respectively.

For the Barcelona lease, the day one non-cash addition of right of use assets due to adoption of ASC 842 was $ 937,000 .

For the years ended December 31, 2025 and 2024, cash paid for amounts included in the measurement of operating liabilities was $ 696,000 and $ 661,000 , respectively.

As of December 31, 2025 and 2024, the weighted-average remaining lease term for the Company’s leases was 1.7 and 2.6 years, respectively.

As of December 31, 2025 and 2024, the weighted-average discount rate for the Company’s leases was 9.93 % and 10.42 %, respectively.

A maturity analysis of the Company’s operating leases as of December 31, 2025 is as follows (amounts in thousands of dollars) :

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The Company was obligated to pay the consultant a monthly retainer in addition to success fee payments of up to an aggregate of $ 4,500,000 for attainment of certain regulatory milestones.

The achievement of the milestones is not probable at this time.

The Company believes that achievement of the milestones is not probable at this time.

No amounts incurred in 2025 and 2024.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

License, Collaborative and Employment Agreements and Commitments – (continued)

Risks and Uncertainties

3 unchanged sentences

The Company is actively monitoring the effects that these disruptions and increasing inflation could have on its operations.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

License, Collaborative and Employment Agreements and Commitments – (continued)

Through the VCN Acquisition, the Company has operations in Spain related to conducting research and development, manufacturing, and clinical trials in Western European countries.

The invasion of Ukraine by Russia, the war in the Middle East, and the retaliatory measures that have been taken, or could be taken in the future, by the United States, NATO, and other countries have created global security concerns that could result in a regional conflict and otherwise have a lasting impact on regional and global economies, any or all of which could disrupt the Company’s supply chain, and despite the fact that it currently does not plan any clinical trials in Eastern Europe, may adversely impact the cost and conduct of R&D, manufacturing, and international clinical trials of its product candidates.

Effective January 1, 2025, we adopted the new income tax disclosure standard (Income Taxes (Topic 740):

Improvements to Income Tax Disclosures) on a prospective basis.

Accordingly, the tables presenting our income tax provision and effective tax rate reconciliation will reflect the new standard for 2025, while the 2024 disclosures will continue to follow the previous disclosure requirements.

Losses before income taxes for the years ended December 31, 2025 and 2024 was as follows:

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Income Taxes – (continued)

Income tax (benefit) provision related to continuing operations differ from the amounts computed by applying the statutory income tax rate of 21 % to pretax loss as follows (in thousands):

Income tax provision (benefit) related to continuing operations differ from the amounts computed by applying the statutory income tax rate of 21 % to pretax loss as follows (in thousands):

Year Ended December 31, 2025

2 unchanged sentences

State and Local Income Taxes, Net of Federal Income Tax Effect

Foreign Tax Effects-Spain

Statutory tax rate difference between Spain and United States

Changes in Valuation Allowances

VCN Impairment

Changes in Valuation Allowances

Nontaxable or Nondeductible Items

Fair Value–Contingent Consideration

Other Nontaxable or Nondeductible amounts

Other Adjustments

Temporary difference true-ups

Section 382 limitation

Foreign Tax Effects-Spain

VCN Impairment

Return to Provision book loss

Statutory tax rate difference between Spain and United States

Changes in Valuation Allowances

NOL adjustment- 382 study

Other Adjustments

Effective Tax Rate

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Income Taxes – (continued)

Deferred Tax Assets and Liabilities

Deferred income taxes reflect the net tax effects of loss and credit carryforwards and temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes.

Deferred income taxes reflect the net tax effects of loss and credit carry forwards and temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes.

Significant components of the Company’s deferred tax assets for federal and state income taxes are as follows (in thousands):

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Amortizable License Fee

ASC 842 Lease Liability

Other Deferred Tax Asset

4 unchanged sentences

Deferred Tax Liabilities:

ASC 842 Net ROU Assets

ASC 842 ROU Asset

Total Gross DTL

Net Deferred Tax Asset (Liability)

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Income Taxes – (continued)

On March 10, 2022, the Company acquired VCN, a Spanish Company in a tax-free stock acquisition.

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At December 31, 2025, the Company has a gross Federal net operating loss carry-forward of approximately $ 1.5 million available to offset future United States taxable income.

In 2024, it was determined that availability of gross Federal net operating losses of $ 72.7 million were fully limited as well as $ 3.9 million of current 2024 net operating losses as a result of change of ownership that occurred in 2024 under Section 382 of the Internal Revenue Code.

In 2024 and 2025, it was determined that availability of gross Federal net operating losses of $ 76.7 million and $ 1.8 million respectfully were fully limited as well as $ 7.4 million of current 2025 net operating losses as a result of change of ownership that occurred in 2025 under Section 382 of the Internal Revenue Code.

State Net Operating Losses are also limited by Section 382 of the Internal Revenue Code and were limited accordingly.

1 unchanged sentence

The foreign net operating loss carries forward indefinitely.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Income Taxes – (continued)

In 2020, the Company completed an Internal Revenue Code Section 382 analysis of its historical net operating loss carry-forward amount.

1 unchanged sentence

The decrease in the prior year net operating loss is attributable to control ownership changes which were determined for the years 2013 and 2018 which caused the reduction in the value of the historical net operating loss carry-forward amounts.

Updated section 382 analysis were performed in 2021, 2022, 2023 to identify if any additional ownership shifts occurred in these years.

It was determined that an ownership shift occurred on January 20, 2021.

The result of the updated Section 382 analysis produced an IRC 382 limit due to the 2021 ownership changes.

There was no ownership change determined for 2022 or 2023.In 2024 it was determined that all of the Company’s Federal and state Net Operating Loss carryforwards through 12/31/2023 as well as a portion of the current year 2024 loss were limited due to an updated 382 study performed in 2024.

As a result of 2024 section 382 study, the Company’s does not have any pre-2018 net operating losses available for use in future tax years.

Updated section 382 analysis were performed in 2021, 2022, 2023 and 2024 to identify if any additional ownership shifts occurred in these years.

It was determined that an ownership shift occurred in January 2021 and in September 2024.

The result of the updated Section 382 analysis produced an IRC 382 limit due to the 2021 and 2024 ownership changes.

There was no ownership change determined for 2022 or 2023.

In 2025 it was determined that all of the Company’s Federal and state Net Operating Loss carry forwards through 12/31/2024 as well as a portion of the current year 2025 loss were limited due to an updated 382 study performed in 2025.

As a result the of 2025 section 382 study, the Company’s does not have any pre-2018 net operating losses available for use in future tax years.

In addition, all post 2017 net operating losses through 12/31/2024 are also not available due the section 382 study.

A portion or $ 1.8 million of the net operating loss carry-forward originating in 2024 is subject to additional limitations based on taxable income.

At December 31, 2024, the Company has a gross foreign net operating loss carryforward of approximately $ 35.4 million Euros related to its Spanish subsidiary, VCN.

The net operating loss does not expire and is available to offset future Spanish taxable income.

$ 1.5 million of the net operating loss carry-forward originating in 2025 is not subject to additional limitations based on taxable income as of December 31, 2025.

The Company’s valuation allowance at December 31, 2025 was approximately $ 12.5 million.

The net change in valuation allowance during the year ended December 31, 2024,was a decrease of $ 17 million due to the following;

$ 22 million federal and state net operating loss write off related to the 382 limitation offset by increase in gross domestic and foreign deferred tax assets of $ 1.6 and $ 3.5 million.

The net change in valuation allowance during the year ended December 31, 2025, was an increase of $ 1.2 million due to the following;

$( .1 ) million federal and state net operating loss related to 382 limitation, an increase in foreign net operating loss of $ 3.4 .

offset by decreases in domestic and foreign deferred tax assets of $( 1.2 ) and $( .9 ) million.

In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred income tax assets will not be realized.

3 unchanged sentences

The Company has also established a valuation allowance in its Spanish tax jurisdictions as it is no longer in a net deferred tax liability position in Spain.

As required under ASU 2023-09, the Company has included only the portion of the valuation allowance related to federal deferred tax assets in the “change in valuation allowance” line of the rate reconciliation.

The following table presents a reconciliation of the total change in the valuation allowance (in thousands):

Year Ended December 31,

Beginning Balance

Change charged to income tax expense

Changes charged to OCI

Ending Balance

Undistributed earnings of the Company’s foreign subsidiary, VCN, are considered to be permanently reinvested and, accordingly, no deferred U.S.

8 unchanged sentences

Subsequent Events

On March 3, 2025, the Company entered into a two-year employment agreement with Steven A.

Shallcross, (the “2025 Shallcross Employment Agreement”), to serve as the Chief Executive Officer and to continue to serve as the Chief Financial Officer of the Company.

The 2025 Shallcross Employment Agreement has a stated term of two years but may be terminated earlier pursuant to its terms.

The terms of the 2025 Shallcross Employment Agreement were substantially the same as the terms of the 2022 Shallcross Employment Agreement except for the stated term.

provided, however, that if his employment is terminated (i) by the Company without Cause or by Mr.

or (ii) by reason of his death or Disability (as defined in the 2025 Shallcross Employment Agreement), then in addition to paying the Accrued Obligations, Mr.

Shallcross would have the right to exercise any vested options until the earlier of six (6) months after termination or the remaining term of the awards.

In such event, if Mr.

Shallcross will have to exercise all vested stock options and other awards that Mr.

Shallcross may have will be equal to the shorter of:

(i) eighteen (18) months after termination, or (ii) the remaining term of the award(s).

If within one (1) year after the occurrence of a Change in Control, Mr.

Shallcross terminates his employment for “Good Reason” or we terminate Mr.

Shallcross’s employment for any reason other than death, disability or Cause, Mr.

Shallcross will be entitled to receive:

(i) the portion of his base salary for periods prior to the effective date of termination accrued but unpaid (if any);

(ii) all unreimbursed expenses (if any);

If within two (2) years after the occurrence of a Change in Control, Mr.

Shallcross terminates his employment for “Good Reason” or the Company terminates Mr.

Shallcross’s employment for any reason other than death, disability or Cause, Mr.

Theriva Biologics, Inc.

and Subsidiaries

Notes to Consolidated Financial Statements

Subsequent Events – (continued)

On February 3, 2025, the Company received $ 1.7 million for the 2023 Research and Development rebate program sponsored by the Spanish government.

On February 17, 2026 the Company entered into a license agreement (the “Rasayana Agreement”) with Rasayana Therapeutics, Inc.

(“Rasayana”), whereby the Company granted Rasayana an exclusive worldwide license with the right to grant sublicenses to Research, Develop, Manufacture and Commercialize (as such terms are defined in the Rasayana License Agreement) any Product (as such term is defined in the Rasayana License Agreement), which includes SYN-020, an oral formulation of the recombinant intestinal alkaline phosphatase enzyme, 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.

Under the terms of the Rasayana License Agreement, the Company received an upfront payment of Three Hundred Thousand Dollars ($ 300,000 ) from Rasayana on the effective date of the Rasayana License Agreement.

In addition, the Company is entitled to receive from Rasayana development milestone payments of up to an aggregate of $ 16,000,000 and sales milestone payments of up to an aggregate of $ 22,000,000 upon achievement of certain development and net sales milestones with respect to Products.

In addition, during the Royalty Term (as such term is defined in the Rasayana License Agreement), the Company is entitled to receive tiered royalties ranging from low to mid single digits on net sales of a Product.

The Company will also be entitled to receive a certain percentage of any Sublicense Revenue (as such term is defined in the Rasayana License Agreement) received by Rasayana or its affiliates.

Under the terms and conditions of the Rasayana License Agreement, Rasayana has agreed to use Commercially Reasonable Efforts (as such term is defined in the Rasayana License Agreement) to meet certain specified Development milestones.

The term of the Rasayana License Agreement commenced on the effective Date and continues on a country-by-country basis until the expiration of the Royalty Term.

If either the Company or Rasayana materially breaches any material obligation under the Rasayana License Agreement and does not cure such breach, the non-breaching party may terminate the Rasayana License Agreement in its entirety;

provided that if such breach is capable of being cured but cannot be cured within such sixty ( 60 ) day period and the breaching party initiates actions to cure such breach within such period and thereafter diligently pursues such actions, the breaching party shall have one additional period of sixty ( 60 ) days to cure such breach..

Either party may also terminate the Rasayana License Agreement, upon written notice, if the other party has an Insolvency Event (as such term is defined in the Agreement).

Rasayana has the right to terminate the Rasayana License Agreement for any or no reason upon ninety ( 90 ) days’ written notice to the Company, including but not limited to instances in which the outcome of a clinical trial is adverse and/or unsatisfactory to Rasayana (in its reasonable discretion).

If Rasayana suspends all material Development efforts with respect to all Products for a period of one hundred and eighty ( 180 ) days, or fails to use Commercially Reasonable Efforts to achieve any of the Development milestones by the applicable deadline), then the Company may terminate the Rasayana Agreement upon ninety ( 90 ) days prior written notice to Rasayana, unless Rasayana resumes material Development efforts within such period.

Upon a termination the rights granted under the Rasayana License Agreement terminate and revert irrevocably to the Company.

On January 22, 2026, the Company 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 the Company incurs in Spain.

The reimbursements can be through either tax credits or direct refunds.

On September 16, 2024, the Company issued a press release noting that its THERICAL project had been awarded € 2.28 million (approximately $ 2.54 million) from the National Knowledge Transfer Program of the Spanish government’s Ministry of Science, Innovation & Universities to support a collaboration between the Company and the Universitat Autònoma de Barcelona (“UAB”) to advance the Company’s suspension cell platform for the clinical manufacture of adenovirus- and adeno-associated virus (“AAV”) therapies.

Under the award, the Company (via its wholly owned subsidiary, Theriva Biologics SL) will receive an unsecured loan (the “Loan”) of € 1.33 million (approximately $ 1.48 million) as a lump sum payment in Q1 2025 which shall bear interest at a rate of 4.015 % and be repaid over 7 years commencing three years from the date of award and UAB will receive a grant of € 0.95 million (approximately $ 1.06 million) dedicated to the THERICEL project and paid in annual installments over the next 3 years .

The loan was funded on January 17, 2025.

Changes in and Disagreements with Accountants on Accounting and Financial Disclosure .

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-K

Item 8. Financial Statements and Supplementary Data