Altimmune Inc

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

(Unaudited)

1. Nature of Business and Basis of Presentation

Nature of Business

Altimmune, Inc., headquartered in Gaithersburg, Maryland, United States, together with its subsidiaries (collectively, the “Company” or “Altimmune”) is a late clinical stage biopharmaceutical company incorporated under the laws of the State of Delaware.

The Company is a late clinical-stage biopharmaceutical company focused on developing novel peptide-based therapeutics for liver and cardiometabolic diseases. The Company’s lead program is pemvidutide (formerly known as ALT-801), a GLP-1/glucagon dual receptor agonist for the treatment of metabolic dysfunction-associated steatohepatitis (“MASH”), obesity, Alcohol Use Disorder (“AUD”) and Alcohol Liver Disease (“ALD”). The Company may also pursue additional indications for pemvidutide that leverage its differentiated clinical profile. Since its inception, the Company has devoted substantially all of its efforts to business planning, research and development, recruiting management and technical staff, and raising capital, and has financed its operations through the issuance of common and preferred stock, long-term debt, and proceeds from research grants and government contracts. The Company has not generated any revenues from the sale of any products to date, and there is no assurance of any future revenues from product sales.

Basis of Presentation

The accompanying unaudited consolidated financial statements are prepared pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) regarding interim financial reporting. Accordingly, they do not include all of the information and disclosures required by accounting principles generally accepted in the United States (“U.S. GAAP”) for complete consolidated financial statements and should be read in conjunction with the audited consolidated financial statements for the year ended December 31, 2024, included in the Annual Report on Form 10-K, which was filed with the SEC on February 27, 2025. In the opinion of management, the Company has prepared the accompanying unaudited consolidated financial statements on the same basis as the audited consolidated financial statements, and these consolidated financial statements include all adjustments, consisting only of normal recurring adjustments, necessary for a fair presentation of the results of the interim periods presented. The operating results for the interim periods presented are not necessarily indicative of the results expected for the full year 2025 or any future years or periods.

The accompanying unaudited consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation.

The accompanying unaudited consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets, and the satisfaction of liabilities in the ordinary course of business. The financial statements do not include any adjustments relating to the recoverability and classification of recorded assets and liabilities that might be necessary should the Company be unable to continue as a going concern.

2. Summary of Significant Accounting Policies

During the three months ended March 31, 2025, there have been no significant changes to the Company’s summary of significant accounting policies contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2024, as filed with the SEC on February 27, 2025.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Significant estimates and assumptions made in the accompanying condensed consolidated financial statements include, but are not limited to, the valuation of share-based awards, income taxes, prepaids, and accruals for research and development activities. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable. However, actual results could differ from those estimates.

Income Taxes

During the three months ended March 31, 2025, the Company has recorded a discrete tax benefit of approximately $0.7 million, related to a portion of carryback claims with the State of Maryland of which the Company previously held an uncertain tax position against. Other than the discrete tax benefit discussed above, due to a full valuation allowance, the Company didnot record an income tax expense (benefit) for either of the three months ended March 31, 2025 and 2024. The Company calculates its quarterly income tax provision based on estimated, annual effective tax rates applied to ordinary income (or loss) and other known items computed and recognized as they occur. The Company’s total provision is based on the United States statutory rate, increased by state and foreign taxes and reduced by a full valuation allowance on the Company’s deferred tax assets.

3. Fair Value Measurements

The Company’s assets measured at fair value on a recurring basis as of March 31, 2025, consisted of the following (in thousands):

The Company’s assets measured at fair value on a recurring basis as of December 31, 2024, consisted of the following (in thousands):

Short-term investments have been initially valued at the transaction price and subsequently valued at the end of each reporting period utilizing third party pricing services or other market observable data (Level 2). The pricing services utilize industry standard valuation models, including both income and market-based approaches and observable market inputs to determine value. The Company’s short-term investments have a maturity date of one year or less.

Short-term investments with quoted prices as of March 31, 2025, as shown below (in thousands):

Short-term investments with quoted prices as of December 31, 2024, as shown below (in thousands):

As of March 31, 2025 and December 31, 2024, none of the unrealized losses on the Company’s short-term investments are a result of credit loss, therefore, any unrealized losses were recognized in OCI.

As of March 31, 2025 and December 31, 2024, the Company had $0.4 million accrued interest on short-term investments included in “Accounts and other receivables” on the accompanying Consolidated Balance Sheets.

Separate disclosure is required for assets and liabilities measured at fair value on a recurring basis from those measured at fair value on a non-recurring basis. Assets recorded at fair value on a non-recurring basis, such as property and equipment and intangible assets are recognized at fair value when they are impaired. During the three months ended March 31, 2025 and year ended December 31, 2024, the Company hadno assets or liabilities that were measured at fair value on a non-recurring basis.

4. Accrued Expenses

Accrued expenses and other current liabilities consist of the following (in thousands):

5. Noncurrent Liabilities

The Company’s noncurrent liabilities are summarized as follows (in thousands):

6. Stockholders’ Equity

The Amended and Restated Certificate of Incorporation, as amended (“Charter”), authorized the Company to issue 200,000,000 shares of common stock, par value $0.0001 per share. As of March 31, 2025, the Company had 77,825,450 shares of common stock issued andoutstanding.

Each share of common stock entitles the holder toone vote on all matters submitted to a vote of the Company’s stockholders. Common stockholders are not entitled to receive dividends, unless declared by the board of directors.

The Charter also authorized the Company to issue 1,000,000 shares of preferred stock, par value $0.0001 per share. As of March 31, 2025, the Company hadno shares of preferred stock issued andoutstanding.

At-the-Market Offerings

On February 27, 2025, the Company entered into an Equity Distribution Agreement (the “2025 Agreement”) with Leerink Partners LLC, Piper Sandler & Co. and Stifel, Nicolaus & Company, Incorporated, serving as sales agents (the “2025 Sales Agents”) with respect to an at-the-market offerings program under which the Company may offer and sell, from time to time at its sole discretion, shares of its common stock, having an aggregate offering price of up to $150.0 million (the “2025 Shares”) through the 2025 Sales Agents (the “2025 Offering”). All Shares offered and sold in the 2025 Offering will be issued pursuant to the Company’s Registration Statement on Form S-3 filed with the SEC on February 27, 2025, which was declared effective on March 13, 2025, and the prospectus supplements related to the 2025 Offering that form a part of the Registration Statement. The Company capitalized approximately $0.3 million of other offering costs which will offset the proceeds received from the shares sold under the 2025 Agreement. During the three months ended March 31, 2025, the Company has sold 805,502 shares of common stock under the 2025 Agreement resulting in approximately $4.6 million in proceeds, net of $0.2 million commission and other offering costs, and as of March 31, 2025, $145.3 million remained available to be sold under the 2025 Agreement. As of March 31, 2025, there was $0.3 million deferred offering costs included in prepaid expenses and other current assets on the accompanying consolidated balance sheets.

On February 28, 2023, the Company entered into an Equity Distribution Agreement (the “2023 Agreement”) with Evercore Group L.L.C., JMP Securities LLC and B. Riley Securities, Inc., serving as sales agents (the “2023 Sales Agents”), with respect to an at-the-market offerings program under which the Company offered and sold shares of its common stock, having an aggregate offering price of up to $150.0 million (the “2023 Shares”) through the 2023 Sales Agents (the “2023 Offering”). All 2023 Shares offered and sold in the 2023 Offering were issued pursuant to the Company’s Registration Statement on Form S-3 filed with the SEC on February 28, 2023. During the three months ended March 31, 2025, the Company has sold 4,467,866 shares of common stock under the 2023 Agreement resulting in approximately $30.2 million in proceeds, net of $1.0 million commission and other offering costs. Since inception through the expiration of the 2023 Agreement in February 2025, the Company sold a total of 26,129,903 shares of common stock resulting in approximately $126.8 million in net proceeds. As of March 31, 2025, there wereno remaining shares available under the 2023 Agreement as the 2023 Agreement was terminated.

7. Stock-Based Compensation

2017 Omnibus Incentive Plan (Omnibus Plan)

The Company’s Omnibus Plan provides for an annual increase on January 1 of each year commencing in 2019 and ending on and including January 1, 2027, up to an amount equal to the lowest of (i)4% of the total number of shares of common stock outstanding on a fully diluted basis as of December 31 of the immediately preceding calendar year, and (ii) such number of shares of common stock, if any, determined by the Company’s board of directors. Accordingly, on January 1, 2025, the number of shares of Common Stock reserved and available for issuance under the Omnibus Plan increased by 3,193,659 shares of common stock.

Stock Options

The Company’s stock option awards generally vest over four years and typically have a contractual life often years. As of March 31, 2025, there was $23.9 million of unrecognized compensation cost related to stock options, which is expected to be recognized over a weighted-average period of 3.0 years. During the three months ended March 31, 2025, the Company granted 1,842,450 stock options with a weighted average exercise price of $6.71 and per share weighted average grant date fair value of $5.48.

Information related to stock options outstanding as of March 31, 2025, is as follows (in thousands, except share, exercise price, and contractual term):

Restricted Stock Units (RSUs)

During the three months ended March 31, 2025, the Company granted 466,700 shares of RSUs with a weighted average grant date fair value of $6.88 which vest over four years. As of March 31, 2025, the Company had unvested RSUs of 1,053,337 shares with total unrecognized compensation expense of $7.6 million, which the Company expects to recognize over a weighted average period of approximately 3.1 years. During the three months ended March 31, 2025, the Company issued 165,259 shares of unrestricted common stock as a result of the vesting of 264,153 RSUs, net of 98,894 shares of common stock withheld to satisfy tax withholding obligations.

2019 Employee Stock Purchase Plan (“ESPP”)

Under the ESPP, employees purchased 32,872 shares for $0.2 million during the three months ended March 31, 2025.

Stock-based Compensation Expense

Stock-based compensation expense is classified in the unaudited consolidated statements of operations and comprehensive loss for the three months ended March 31, 2025 and 2024 as follows (in thousands):

8. Net Loss Per Share

Because the Company has reported net loss attributable to common stockholders for the three months ended March 31, 2025 and 2024, basic and diluted net loss per share attributable to common stockholders in each period are the same.

Basic net loss per share attributable to common stockholders is computed by dividing the net loss attributable to common stockholders by the weighted average numbers of shares of common stock outstanding for the period.

Diluted net loss per share is calculated by adjusting weighted average shares outstanding for the dilutive effect of common stock equivalents outstanding for the period. As such, all unvested RSUs and stock options have been excluded from the computation of diluted weighted average shares outstanding because such securities would have an anti-dilutive impact for all periods presented.

Potential common shares issuable upon conversion, vesting, or exercise of unvested RSUs and stock options that are excluded from the computation of diluted weighted-average shares outstanding, as they are anti-dilutive, are as follows:

9. Commitments and Contingencies

Spitfire Acquisition

In July 2019, the Company entered into the Spitfire merger agreement to acquire all of the equity interests of Spitfire Pharma, Inc. (“Spitfire”). Spitfire was a privately held, preclinical pharmaceutical company developing novel peptide products for pharmaceutical indications, including pemvidutide for the treatment of MASH. As part of the agreement, the Company is obligated to make payments of up to $80.0 million upon the achievement of specified worldwide net sales of all products developed using the technology acquired from Spitfire Pharma, Inc. (the “Sales Milestone”) withinten years following the approval of a new drug application filed with the U.S. Food and Drug Administration (the “FDA”).

The contingent payments related to the Sales Milestones are predominately cash-based payments accounted for under FASB Accounting Standards Codification Topic 450, Contingencies. Accordingly, the Company will recognize the Sales Milestones when the contingency is probable and the amount can be reasonably estimated.

Litigation

On June 4, 2024, a shareholder derivative complaint was filed in federal district court in the District of Delaware, purportedly on behalf of the Company, naming as defendants three of the Company’s executive officers andeight of the

Company’s board members, which is now captionedIn re Altimmune, Inc. Stockholder Derivative Litigation, No. 1:24-cv-669 (D. Del.) (the “Derivative Action”). The complaint is based upon allegations that are similar to those alleged in a class action complaint previously filed against usIn re Altimmune, Inc. Securities Litigation, No. 24-cv-01315 (D. Md.) (the “Class Action”) and alleges claims for contribution, breaches of fiduciary duty, unjust enrichment, and waste of corporate assets based on the defendants purportedly making or causing to be made false and misleading statements and omissions of material fact between December 1, 2023 and April 26, 2024. The complaint seeks unspecified monetary relief, exemplary damages, restitution, contribution, and costs, as well as equitable relief. A similar shareholder derivative complaint, captioned Alaraidah v. Garg, et al., No. 1:24-cv-00772 (D. Del.), was filed in the same court by another plaintiff on July 1, 2024, based upon substantially similar allegations, and alleges claims for contribution, breach of fiduciary duties, unjust enrichment, abuse of control, gross mismanagement, and waste of corporate assets and seeks unspecified monetary relief, restitution, costs, and equitable relief. These actions were consolidated for all purposes on July 18, 2024 into the Derivative Action. On February 3, 2025, pursuant to a joint stipulation of the parties, the court ordered that the Derivative Action be dismissed without prejudice and the case was closed.

The Company is a party in various contracts and subject to disputes, litigation, and potential claims arising in the ordinary course of business none of which are currently reasonably possible or probable of material loss.

10. Segment Information

The Company is a late clinical stage biopharmaceutical company focused on developing novel peptide-based therapeutics for liver and cardiometabolic diseases. The Company’s lead program is pemvidutide, a GLP-1/glucagon dual receptor agonist for the treatment of MASH, obesity, AUD and ALD. To date, the Company has not generated any revenue from the sale of any products.

The chief operating decision maker assesses the performance of the Company and decides how to allocate resources based solely on net (loss) income, which is also reported on the consolidated statements of operations and consolidated loss as net (loss) income. The measure of segment assets is reported on the consolidated balance sheet as total assets.

11. Subsequent Events

The Company evaluated subsequent events through the issuance date of the financial statements on this quarterly report on Form 10-Q.

During April 2025 and through the date of the issuance of the financial statements, the Company raised $16.3 million in net proceeds through the issuance of 3,278,902 shares of common stock pursuant to the 2025 Offering.

On May 13, 2025 (“Closing Date”), the Company entered into a Loan and Security Agreement (“Loan Agreement”) with Hercules Capital, Inc. (“Hercules”) and the lenders party thereto, pursuant to which the lenders will make available up tofour tranches of term loans in an aggregate principal amount of $100.0 million (the “Term Loan”), subject to certain terms and conditions. The first Term Loan tranche was made on the Closing Date in an aggregate principal amount of $15.0 million. Upon the achievement of certain milestones and subject to other terms and conditions set out in the Loan Agreement, (i) the second Term Loan tranche will be made available in an aggregate principal amount of up to $25.0 million and (ii) the third Term Loan tranche will be made available in an aggregate principal amount of up to $15.0 million. The fourth Term Loan tranche will be made available in an aggregate principal amount of up to $45.0 million subject to the approval of the lenders. The Term Loan will mature on June 1, 2029 (the “Maturity Date”). The Term Loan bears interest equal to the greater of (a) theprime rate as reported in The Wall Street Journal plus 2.45% and (b) (i)9.95% until December 31, 2025, and (ii)9.45% thereafter. The Company may make interest-only payments for an initial period of up to 24 months from the Closing Date, which may be extended up to 42 months upon achievement of certain milestones and subject to other terms and conditions set out in the Loan Agreement (the “Interest-Only Period”). After the Interest-Only Period, the Company will be required to repay in equal monthly installments the principal and interest until the Maturity Date.