DELCATH SYSTEMS, INC.

(amounts in thousands, except share and per share amounts)

(1)General

The unaudited interim condensed consolidated financial statements of Delcath Systems, Inc. (“Delcath” or the “Company”) as of and for the three and six months ended June 30, 2026 and 2025 should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2025 (the “Annual Report”), which was filed with the Securities and Exchange Commission (the “SEC”) on February 26, 2026 and may also be found on the Company’s website (www.delcath.com). The information contained on, or that can be accessed through, our website is not incorporated by reference into these financial statements or in any report or document we have filed or may file with the SEC and any reference to our website address is intended to be an inactive textual reference only. In these notes to the interim condensed consolidated financial statements the terms “us”, “we” or “our” refer to Delcath and its consolidated subsidiaries.

Description of Business

The Company is an interventional oncology company focused on the treatment of cancers primary or metastatic to the liver. The Company’s lead product, the HEPZATOTM KIT (melphalan for Injection/Hepatic Delivery System), a drug/device combination product (“HEPZATO” or “HEPZATO KIT”), was approved by the U.S. Food and Drug Administration (the “FDA”) on August 14, 2023, indicated as a liver-directed treatment for adult patients with uveal melanoma with unresectable hepatic metastases affecting less than 50% of the liver and no extrahepatic disease, or extrahepatic disease limited to the bone, lymph nodes, subcutaneous tissues, or lung that is amenable to resection, or radiation. The first commercial use of the HEPZATO KIT for the treatment of metastatic uveal melanoma (“mUM”) occurred in January 2024.

In the United States, HEPZATO is considered a combination drug and device product and is regulated as a drug by the FDA. Primary jurisdiction for regulation of HEPZATO has been assigned to the FDA’s Center for Drug Evaluation and Research. The FDA has granted Delcathsix orphan drug designations (five for melphalan in the treatment of patients with ocular (uveal) melanoma, cutaneous melanoma, intrahepatic cholangiocarcinoma, hepatocellular carcinoma, and neuroendocrine tumor indications andone for doxorubicin in the treatment of patients with hepatocellular carcinoma).

The Company has sufficient raw material and component constituent parts of the HEPZATO KIT to meet anticipated demand and it intends to manage supply chain risk through stockpiled inventory and, where commercially reasonable, contracting with multiple suppliers for critical components.

In Europe, the hepatic delivery system is a stand-alone medical device having the same device components as HEPZATO, but without the melphalan hydrochloride and is approved for sale under the trade name CHEMOSAT Hepatic Delivery System for Melphalan (“CHEMOSAT”), where it has been used at major medical centers to treat a wide range of cancers in the liver. On February 28, 2022, CHEMOSAT received Medical Device Regulation (“MDR”) certification under the European Medical Devices Regulation (EU) 2017/745, which may be considered by jurisdictions when evaluating reimbursement. In June 2025, CHEMOSAT was approved for reimbursement fortwo years in the Vastra Gotaland Region in Sweden.

On October 18, 2025, the Company announced the results of the investigator-initiated CHOPIN clinical trial. The randomized Phase 2 trial was designed to compare the safety, tolerability, and efficacy of CHEMOSAT with melphalan for percutaneous hepatic perfusion (PHP) when used alone versus when combined with systemic administration of the immune checkpoint inhibitors (ICI) ipilimumab and nivolumab. Ipilimumab and nivolumab are approved by the FDA and European Union for the treatment of unresectable metastatic melanoma. The CHOPIN trial included 76 patients randomized 1:1 to receive two PHP treatments alone at weeks one and seven (PHP group) or four cycles of ICI every three weeks over approximately nine weeks with two PHP treatments at weeks one and seven (combination group). The primary study endpoint of one-year progression-free survival rate was met with 54.7% in the combination group versus 15.8% in the PHP group (adjusted HR 0.34; p=0.0002). The secondary endpoints included Safety, Overall Survival (“OS”), Progression Free Survival (“PFS”) and Overall Response Rate (“ORR”). The combination group saw an increase in median OS of 23.1 months versus 19.6 months (adjusted HR = 0.39; p = 0.0065), median PFS 12.8 months versus 8.3 months (adjusted HR = 0.34; p=0.0002) and ORR of 76.3% in the combination group versus 39.5% (p<0.001). Grade 3 or higher treatment-related adverse events were more frequent in the combination group (82% versus 41%, P=0.0006), but most were self-limiting and manageable with standard care. Overall, the combination treatment was well tolerated, with types, rates and frequencies of adverse events consistent with individual use of PHP and checkpoint inhibitors. No new safety signals were identified.

To support the New Drug Application for HEPZATO the Company conducted the FOCUS Clinical Trial for Patients with metastatic hepatic dominant Uveal Melanoma (the “FOCUS Trial”), a global registration clinical trial that investigated objective response rate in patients with mUM. On May 6, 2024, the Company announced the publication of results from the pivotal FOCUS Trial in the journal Annals of Surgical Oncology. On April 9, 2025, the Company announced the publication of a comparative analysis of the randomized portion of the FOCUS Trial in the Annals of Surgical Oncology. On December 31, 2025, the Company announced the publication of subgroup analyses of the Phase 3 FOCUS Trial in the Journal of Cancer Research and Clinical Oncology. Currently, the Company’s clinical development program is seeking to generate clinical data for CHEMOSAT and HEPZATO either as a monotherapy or in combination with immunotherapy. The Company expects that this will support increased clinical adoption of and reimbursement for CHEMOSAT in Europe, and to support reimbursement in various jurisdictions, including the United States for HEPZATO.

In addition to HEPZATO’s use to treat mUM, the Company believes that HEPZATO has the potential to treat other cancers in the liver, such as metastatic colorectal cancer, metastatic breast cancer, metastatic neuroendocrine tumors, metastatic pancreatic cancer, intrahepatic cholangiocarcinoma and non-small cell lung cancer. The Company believes that those and similar disease states are areas of unmet medical needs that represent significant market opportunities.

The Company’s investigational new drug application (“IND”) for a Phase 2 clinical trial evaluating HEPZATO in combination with standard of care (“SOC”) for liver-dominant metastatic colorectal cancer was cleared by the FDA in December 2024. The Phase 2 trial will evaluate the safety and efficacy of HEPZATO in combination with trifluridine-tipiracil and bevacizumab compared to trifluridine-tipiracil and bevacizumab alone in patients with liver-dominant mCRC receiving third-line treatment. Approximately 90 patients will be enrolled in this randomized, controlled trial. Patient enrollment began during the third quarter of 2025, with the study expected to take place at more than 20 sites across the United States and Europe. In July 2025, the Company received authorization from the European Union and United Kingdom regulatory authorities for the clinical study of Melphalan for Injection/Hepatic Delivery System in patients with refractory metastatic colorectal cancer with liver dominant disease.

On April 28, 2025, the Company announced the clearance by the FDA of its IND application for the Phase 2 clinical trial of HEPZATO in liver-dominant metastatic breast cancer. The Phase 2 trial will evaluate the safety and efficacy of HEPZATO in combination with SOC versus SOC alone in patients with liver-dominant HER2-negative mBC following the failure of previous treatments. The SOC options will be the physician’s choice of eribulin, vinorelbine or capecitabine. We expect approximately 90 patients will be enrolled in this randomized, controlled trial. The trial will take place at more than 15 sites across the United States and Europe, patient enrollment began in the third quarter of 2026.

Risks and Uncertainties

As detailed in the Annual Report, the Company is subject to risks common to companies in the biopharmaceutical industry including, but not limited to, the risks associated with developing product candidates and successfully launching and commercializing its drug/device combination products for additional indications, obtaining regulatory approval of its products in the United States and other geographies for additional indications, the uncertainty of the broad adoption of its approved products by physicians and consumers, obtaining and maintaining sufficient reimbursement for approved products and/or the associated procedures to healthcare professionals and treating facilities, and significant competition.

Factors such as geopolitical events, including war, terrorism and civil and political unrest, such as the ongoing conflicts in the Middle East and between Russia and Ukraine, global health outbreaks, adverse weather events, labor or raw material shortages, imposition of tariffs or trade restrictions and other supply chain disruptions could result in difficulties, shortages and delays in manufacturing the Company’s products, which could have an adverse impact on its results of operations or cause an increase in the cost of ongoing or planned clinical trials. The Company may also have to take inventory write-offs and incur other charges and expense for products that fail to meet specifications, undertake costly remediation efforts or seek more costly manufacturing alternatives. Such developments could increase its manufacturing costs, cause it to lose revenue or market share as patients and physicians turn to competing therapeutics, diminish its profitability or damage its reputation.

The United States has announced and implemented a broad range of tariffs on goods imported into the United States, many of which were then paused or cancelled. The majority of the Company’s sales are domestic, though CHEMOSAT is sold only outside of the United States, and while the Company sources certain components outside of the United States, the costs associated with imported materials needed for its operations is a modest portion of its overall manufacturing costs. The Company will continue to monitor the implementation and effect of existing and other proposed tariffs and other geopolitical events, such as the ongoing conflicts in the Middle East and between Russia and Ukraine and may take actions as a result thereof in order to attempt to alleviate certain risks and uncertainties that may be caused by such events.

Liquidity

The accompanying condensed consolidated financial statements have been prepared on a basis which assumes that the Company will continue as a going concern and contemplates the realization of assets and the satisfaction of liabilities and commitments in the normal course of business.

At June 30, 2026, the Company had cash and cash equivalents totaling $47.5 million and short-term investments totaling $48.4 million.

The Company believes that the current cash on hand, cash equivalents, investments and net cash provided by operating activities will be sufficient to support current operations through at least 12 months from the issuance of these condensed consolidated financial statements. Actual future liquidity and capital requirements will depend on numerous factors, including the initiation and progress of clinical trials and research and product development programs; obtaining regulatory approvals and complying with applicable laws and regulations; the timing and effectiveness of product commercialization activities, including marketing arrangements; the timing and costs involved in preparing, filing, prosecuting, defending and enforcing intellectual property rights; the resolution of any disputes with third parties; and the effect of competing technological and market developments.

Basis of Presentation

These interim condensed consolidated financial statements are unaudited and were prepared by the Company in accordance with generally accepted accounting principles in the United States of America (“GAAP”) and with the SEC’s instructions to Form 10-Q and Article 10 of Regulation S-X. They include the accounts of all wholly owned subsidiaries and all significant inter-company accounts and transactions have been eliminated in consolidation.

The preparation of interim condensed consolidated financial statements requires management to make assumptions and estimates that impact the amounts reported. These interim condensed consolidated financial statements reflect all adjustments, consisting of normal recurring accruals, necessary for a fair presentation of the Company’s results of operations, financial position and cash flows for the interim periods ended June 30, 2026 and 2025; however, certain information and footnote disclosures normally included in our audited consolidated financial statements which were included in the Annual Report have been condensed or omitted as permitted by GAAP. It is important to note that the Company’s results of operations and cash flows for interim periods are not necessarily indicative of the results of operations and cash flows to be expected for a full fiscal year or any interim period.

Significant Accounting Policies

Management has performed its quarterly evaluation of policies and there have been no material changes to our significant accounting policies as set forth in “Note 3 - Summary of Significant Accounting Policies” to the consolidated financial statements included in the Annual Report.

Recent Accounting Pronouncements

No new accounting standards were adopted during the six months ended June 30, 2026. The Company’s management does not believe that any other recently issued, but not yet effective, authoritative guidance, if currently adopted, would have a material impact on the Company’s financial statements presentation or disclosures.

ASU 2025-06, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40)

In September 2025, the Financial Accounting Standards Board (“FASB”) issued ASU 2025-06, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software. Such standard is intended to modernize old internal-use software guidance and expand the existing guidance on capitalizing implementation costs for cloud computing arrangements that are service contracts. The effective date for this standard is for fiscal years beginning after December 15, 2027, and interim periods within those fiscal years. Early adoption is permitted as of the beginning of an annual reporting period. The Company is currently evaluating the effects adoption of this guidance will have on the consolidated financial statements.

ASU 2024-03, Disaggregation of Income Statement Expenses

In November 2024, the FASB issued ASU 2024-03, Income Statement - Reporting Comprehensive Income (Topic 220): Expense Disaggregation Disclosures to improve the disclosures about a public entity’s expenses and provide more detailed information about the types of expenses in commonly presented expense captions such as inventory purchases, employee compensation, depreciation and intangible asset amortization. The disclosure requirements must be applied retrospectively to all prior periods presented in the financial statements. The effective date for the standard is for fiscal years beginning after December 15, 2026 and interim periods within fiscal years beginning after December 15, 2027, with early adoption permitted. The Company is currently evaluating the effects adoption of this guidance will have on the consolidated financial statements.

(2)Revenue

The Company recognizes product revenue from sales of HEPZATO in the United States and CHEMOSAT in certain European countries in accordance with the five-step model in Accounting Standards Codification (ASC) 606, Revenue from Contracts with Customers: (i) identify contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenues when (or as) the Company satisfies the performance obligation. Under this revenue standard, the Company recognizes revenue when its customer obtains control of the promised goods, in an amount that reflects the consideration which the Company expects to receive in exchange for those goods.

Payment terms, returns, and warranties

The Company’s revenue arrangements do not contain significant financing components as payment terms are generally 30 to 60 days. HEPZATO and CHEMOSAT have no contractual rights of returns, refunds or similar obligations beyond assurance-type quality warranties. HEPZATO or CHEMOSAT kits that are deemed defective are replaced at no cost to the hospital or treating center.

The Company does not have any contract assets or contract liabilities at June 30, 2026 or 2025 because the contracts generally do not include performance obligations satisfied over time or advance customer consideration.

HEPZATO

The Company ships and sells HEPZATO directly to hospitals and treating centers based on approved agreements. For certain customers, the inventory is considered on consignment in which the Company retains title to the product until the use of the HEPZATO. For these sales, the Company recognizes HEPZATO revenue, based on contracted or published rates, upon completion of the procedure. There is no obligation for the hospitals or treating centers to use the consigned HEPZATO, and the Company has no contractual right to receive payment until the product is used in a procedure and transfer of control is completed. See “Note 4 -Inventory” for further information regarding consignment inventory.

Hospitals and treating centers may also elect to purchase HEPZATO prior to a procedure. For these sales, the purchasing hospital or treatment center obtains control of the product once it is delivered. In these instances, the Company recognizes revenue based on contracted rates stated in an approved contract or purchase order upon delivery to the customer.

On May 22, 2025, the Company announced a plan to enter into a National Drug Rebate Agreement (“NDRA”) with the Centers for Medicare and Medicaid Services (“CMS”), which also subjected the Company to entering into a Pharmaceutical Pricing Agreement (“PPA”) with the Public Health Service and a master agreement with the U.S. Department of Veterans Affairs (“VA”). Pursuant to the NDRA, the Company must pay mandated rebates to states for Medicaid usage. The rebates are variable consideration and must be estimated at each reporting period and are treated as a reduction of revenue in the same period the related revenue is recognized. These estimates are based on historical experience and payer mix and will be adjusted as actual claims are processed. At June 30, 2026, there were no accrued rebates included in the Company’s financials.

Under the PPA, beginning on July 1, 2025, the Company began selling HEPZATO to eligible covered entities at the statutory 340B price. The Company is also obligated to make any sales to the VA at the Federal Ceiling Price. Due to the Company selling directly to the hospital or treating center, the purchase price of either wholesale acquisition cost or 340B is known at the time of revenue recognition. No chargeback estimate is recorded on the condensed consolidated balance sheets.

The NDRA, the PPA, and the agreement with the VA requires the Company to calculate and submit additional pricing calculations and subject the Company to potential penalties for failing to make timely and/or accurate reports of the required values.

CHEMOSAT

CHEMOSAT is sold directly to hospitals in the European Union and United Kingdom based on contracted rates in an approved contract or sales order. The Company recognizes product revenue from sales of CHEMOSAT upon shipment.

Revenue by product for the periods indicated were as follows:

Concentration of Credit Risk

Potential credit risk exposure for both the HEPZATO KIT and CHEMOSAT has been evaluated for the Company’s accounts receivable in accordance with ASC 326, Financial Instruments - Credit Losses. The loss percentage is calculated through the use of current and historical economic and financial information. As of June 30, 2026, there were no estimated losses applied to the accounts receivables balance.

The Company’s total percentage of revenue and accounts receivable balances were comprised of the following concentrations from its largest customers, based on whose revenue and/or accounts receivable concentration is greater than 10% of the Company’s total revenue or total accounts receivable in the periods disclosed below:

(3)Investments

Marketable debt securities held by the Company are classified as available-for-sale pursuant to ASC 320, Investments - Debt and Equity Securities, and carried at fair value in the accompanying condensed consolidated balance sheets.

The following table summarizes the gross unrealized gains on the Company’s marketable securities as of June 30, 2026:

As of June 30, 2026, there was $0.3 million of interest receivable related to the outstanding debt securities held by the Company.

The following table summarizes the gross unrealized gains on the Company’s marketable securities as of December 31, 2025:

As of December 31, 2025, there was $0.5 million of interest receivable related to the outstanding debt securities held by the Company.

(4)Inventory

Inventory consists of the following:

The Company has consignment agreements with approved hospitals and treatment centers. As of June 30, 2026, there was approximately $0.7 million in finished goods held at hospitals and treatment centers.

During the six months ended June 30, 2026, the Company has included a reserve of $0.5 million for inventory expected to expire prior to usage.

(5)Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consist of the following:

(6)Property, Plant, and Equipment

Property, plant, and equipment consist of the following:

Depreciation expense for the three and six months ended June 30, 2026 was $0.1 million and $0.2 million, respectively. Depreciation for both the three and six months ended June 30, 2025 was less than $0.1 million.

(7)Accrued Expenses

Accrued expenses consist of the following:

(8)Leases

The Company recognizes right-of-use (“ROU”) assets and lease liabilities when it obtains the right to control an asset under a leasing arrangement with an initial term greater than twelve months. The Company leases its facilities under non-cancellable operating leases. The Company evaluates the nature of each lease at the inception of an arrangement to determine whether it is an operating or financing lease and recognizes the ROU asset and lease liabilities based on the present value of future minimum lease payments over the expected lease term. The Company’s leases do not generally contain an implicit interest rate and therefore the Company uses the incremental borrowing rate it would expect to pay to borrow on a similar collateralized basis over a similar term in order to determine the present value of its lease payments.

For both the three and six months ended June 30, 2026 and 2025, the Company recognized approximately $0.1 million of operating lease and less than $0.1 million of short-term lease expense.

In 2021, the Company entered into a sub-lease agreement (the “2021 Sub-Lease”) with its previous sub-lessee pursuant to which, effective August 2, 2021, the previous sub-lessee would become the lessee and the Company would then sublease its portion of the premises in Galway, Ireland from the previous sub-lessee. The Company’s annual rent expense under the 2021 Sub-Lease is less than$0.1 million for a term of 5 years. The Company elected not to renew this lease and the lease will expire upon its terms on August 2, 2026.

On May 25, 2026, the Company entered into a lease agreement (the “Galway Lease”) to lease approximately 6,700 square feet of distribution and office space in Galway, Ireland. The term of the lease isten years. The Company’s annual rent expense under the Galway Lease is approximately$0.2 million for the first five years. A rent review will occur at the end of the fifth year with an increase or decrease in line with the cumulative movement in the Consumer Price Index with a total increase or decrease not to exceed 3%.

On January 18, 2024, the Company entered into a lease agreement (the “Queensbury Lease”) to lease approximately 18,000 square feet of manufacturing and office space in Queensbury, New York. The initial term of the lease isfive years with a right to extend the lease by an additional five years, exercisable under certain conditions set forth in the Queensbury Lease. The Company’s annual rent expense under the Queensbury Lease is less than$0.2 million for a term of 5 years.

The following table summarizes the Company’s operating leases as of June 30, 2026:

Remaining maturities of the Company’s operating leases, excluding short-term leases, are as follows:

(9)Stockholders’ Equity

Public and Private Placements

June 2024 Shelf Registration Statement

On June 28, 2024, the Company filed a universal shelf registration statement on Form S-3 (the “June 2024 Shelf Registration Statement”) with the SEC, pursuant to which the Company may offer, issue and sell any combination of shares of the Company’s common stock, par value $0.01 per share, shares of the Company’s preferred stock, par value $0.01 per share, debt securities, warrants to purchase common stock, preferred stock and/or debt securities, in one or more series, and units consisting of any combination of the other types of securities registered under such June 2024 Shelf Registration Statement in an aggregate amount of up to $150 million, in each case, to the public in one or more registered offerings. The June 2024 Shelf Registration Statement was declared effective on August 5, 2024.

Authorized Shares

The Company is authorized to issue 80 million shares of common stock, $0.01 par value, and 10 million shares of preferred stock, $0.01 par value. As of June 30, 2026, the Company has designated the following preferred stock:

Preferred Stock

As of June 30, 2026, there were an aggregate of 10,957 shares of Series E and Series E-1,1,085 Series F-2 and 2,150 Series F-4 Convertible Preferred Stock outstanding, respectively.

Subject to limitations set forth in the Beneficial Ownership Limitation, the shares of Series E and E-1 Preferred Stock are convertible into common stock at the option of the holder at the conversion price of $10.00 per share.

Subject to limitations set forth in the Certificate of Designation, the shares of Series F-2 and F-4 Preferred Stock are convertible into common stock at the option of the holder at the conversion price of $3.30 per share and $6.00 per share, respectively, rounded down to the nearest whole share, and in each case subject to the terms and limitations contained in the Certificate of Designation.

Share Repurchase Program

On November 19, 2025, the Company’s Board of Directors authorized a share repurchase program under which the Company may repurchase up to $25.0 million of its outstanding shares of common stock, from time to time, through open market transactions, privately negotiated transactions or in such other manners approved by the Board of Directors, in accordance with all applicable securities laws and regulations, including Rule 10b-18 of the Exchange Act. The Company may enter into a pre-arranged stock trading plan in accordance with the guidelines specified under Rule 10b5-1 to effectuate all or a portion of the share repurchase program. The repurchase program does not obligate the Company to purchase any shares and does not have an expiration date. The timing and method of any repurchases, which will depend on a variety of factors, including market conditions, are subject to our results of operations, financial condition, liquidity and other factors.

As of June 30, 2026, there have been 945,665 shares of common stock repurchased and retired under the repurchase program at an average price paid per share of $9.5085 for a total aggregate purchase price of approximately $9.0 million, which includes 628,572 shares of common stock repurchased prior to 2026 for an aggregate purchase price of $6.0 million. The Company had approximately $16.0 million remaining under the share repurchase program at June 30, 2026.

Omnibus Equity Incentive Plan

On September 30, 2020, the Company’s 2020 Omnibus Equity Incentive Plan (the “2020 Plan”) was adopted by the Company’s Board of Directors. On November 23, 2020, the Company’s stockholders approved the 2020 Plan. The 2020 Plan will continue in effect until the tenth anniversary of the date of its adoption by the Board or until earlier terminated by the Board. The 2020 Plan is administered by the Board of Directors or a committee designated by the Board of Directors. The 2020 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance awards, as well as other share-based awards or cash awards that are deemed to be consistent with the purposes of the plan to Company employees, directors and consultants. As of June 30, 2026, there have been 11,125,000 shares of common stock reserved under the 2020 Plan, which includes the additional 1,800,000 shares approved by shareholders on May 13, 2026, of which 2,558,953 shares of common stock remained available to be issued as of June 30, 2026 under the 2020 Plan.

In addition to options granted from the 2020 Plan, the Company also grants employment inducement awards pursuant to Listing Rule 5635(c)(4) of the corporate governance rules of the Nasdaq Stock Market. The inducement grants are intended to provide incentive to certain individuals to enter into employment with the Company. Prior to December 5, 2023, the inducement awards were granted outside of the 2020 Plan, however they are governed in all respects as if they were issued under the 2020 Plan. These grants do not reduce the number of options available for issuance under the 2020 Plan.

Inducement Plan

On December 5, 2023, the Company’s 2023 Inducement Plan (the “2023 Plan”) was adopted by the Company’s Board of Directors. The 2023 Plan is administered by a Compensation Committee of two or more Independent Directors appointed by the Board of Directors and is intended to provide for the grant of non-qualified stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance awards, as well as other share-based awards or cash awards that are deemed appropriate to incentivize employment with the Company. Awards from the 2023 Plan can only be granted to individuals who have not previously worked for the Company or have not worked for the Company for a bona fide period of time. As of June 30, 2026, there have been 1,100,000 shares of common stock reserved under the 2023 Plan, of which 92,842 remain available to be granted.

Stock Options

The following tables include information for all options granted including inducement grants that are granted outside of the 2020 Plan.

The Company values stock options using the Black-Scholes option pricing model and used the following assumptions, on a weighted-average basis, during the reporting periods:

The following is a summary of stock option activity for the six months ended June 30, 2026:

The weighted average grant-date fair value of stock options granted during the six months ended June 30, 2026 and 2025 was $6.17 and $11.82, respectively. The aggregate intrinsic value of stock options exercised was $1.1 million and $2.2 million for the six months ended June 30, 2026 and June 30, 2025, respectively. Total cash received as a result of stock option exercises was $1.2 million and $1.5 million for the six months ended June 30, 2026 and June 30, 2025, respectively.

Restricted Stock Units

The following tables include information for all restricted stock units granted including inducement grants that are granted outside of the 2020 Plan.

The following is a summary of share-based compensation expense in the statements of operations:

At June 30, 2026, there was $16.2 million of aggregate unrecognized compensation expense related to employee and board stock option grants and restricted stock unit grants. The cost is expected to be recognized over a weighted average period of 1.06 years.

Common Stock Warrants

The following is a summary of common stock warrant activity for the six months ended June 30, 2026:

The following table presents information related to common stock warrants outstanding at June 30, 2026:

(1) Pre-funded warrants with a $0.01 exercise price do not expire until exercised.

Employee Stock Purchase Plan

In August 2021, the Company’s Board of Directors, with shareholder approval in May 2022, adopted the Employee Stock Purchase Plan (the “ESPP”). The ESPP provides for a maximum of 560,295 shares of common stock to be purchased by participating employees, of which 217,372 have been issued as of June 30, 2026 since the inception of the benefit in 2021. Employees who elect to participate in the ESPP will be able to purchase common stock at the lower of 85% of the fair market value of common stock on the first or last day of the applicablesix-month offering period.

(10)Net (Loss) Income per Share

Basic net income or loss per share is determined by dividing net loss by the weighted average shares of common stock outstanding during the period, without consideration of potentially dilutive securities, except for those shares that are issuable for little or no cash consideration. Diluted net income or loss per share is determined by dividing net income or loss by diluted weighted average shares outstanding. Diluted weighted average shares reflects the dilutive effect, if any, of potentially dilutive common shares, such as stock options and warrants calculated using the treasury stock method. In periods with reported net operating losses, all common stock options, convertible preferred shares, and preferred and common warrants are generally deemed anti-dilutive such that basic net loss per share and diluted net loss per share are equal.

At both June 30, 2026 and 2025, the Company had 1,341,375 pre-funded warrants outstanding. The following table provides a reconciliation of the weighted average shares outstanding calculation for the three and six months ended June 30, 2026 and 2025:

The following potentially dilutive securities were excluded from the computation of earnings per share as of June 30, 2026 and 2025 because their effects would be anti-dilutive:

(11)Income Taxes

The Company has recorded a provision for income taxes of $0.7 million for both the six months ended June 30, 2026 and June 30, 2025, respectively.

As discussed in “Note 14 - Income Taxes” to the notes to the consolidated financial statements contained in the Annual Report, the Company has a valuation allowance against the full amount of its net deferred tax assets. The Company currently provides a valuation allowance against deferred tax assets when it is more likely than not that some portion or all of its deferred tax assets will not be realized. The Company has not recognized any unrecognized tax benefits in its balance sheet.

The Company is subject to income tax in the U.S., as well as various state and international jurisdictions. The federal and state tax authorities can generally reduce a net operating loss (but not create taxable income) for a period outside the statute of limitations in order to determine the correct amount of net operating loss which may be allowed as a deduction against income for a period within the statute of limitations. Additional information regarding the statutes of limitations can be found in Note 14 Income Taxes of the Annual Report.

On July 4, 2025, President Trump signed into law the One Big Beautiful Bill Act (OBBBA), which resulted in the extension of many provisions of the current tax law as well as other rule changes, including full expensing of U.S. research and development costs under Section 174A, and retroactive expensing of unamortized U.S. research and development costs capitalized between 2022 and 2024. Additional information regarding the effect of OBBBA on the Company’s tax provision can be found in Note 14 Income Taxes of the Annual Report.

(12)Commitments and Contingencies

medac Matter

In April 2021, the Company’s wholly owned subsidiary, Delcath Systems Ltd, issued to medac GmbH, a privately held, multi-national pharmaceutical company based in Germany (“medac”), an invoice for a €1 million milestone payment under a License, Supply and Marketing Agreement dated December 10, 2018 (the “medac Agreement”) between medac and the Company. The medac Agreement provided to medac the exclusive right to market and sell CHEMOSAT in certain designated countries for which the Company was entitled to a combination of upfront and success-based milestone payments as well as a fixed transfer price per unit of CHEMOSAT and specified royalties.

In response to medac’s subsequent dispute and non-payment of the invoice, on October 12, 2021, the Company notified medac in writing that it was terminating the medac Agreement due to medac’s nonpayment of the €1 million milestone payment, with the effective date of termination of the medac Agreement being April 12, 2022. On December 16, 2021, the Company initiated an arbitration proceeding pursuant to the dispute resolution procedures of the medac Agreement for the non-payment of the invoice.

On December 30, 2022, the parties reached a final settlement of the matter and the Company agreed to pay medac either (a) a royalty on sales of CHEMOSAT units over a defined minimum for a period offive years or until a maximum payment has been reached, or (b) a minimum annual payment of $0.2 million in the event the annual royalty payment does not reach the agreed minimum payment amount. The Company has estimated the remaining fair value of the settlement to be $0.6 million as of June 30, 2026 and recorded $0.3 million as other liabilities, non-current and $0.3 million as accrued expenses on the Company’s condensed consolidated balance sheet as of June 30, 2026.

Manufacturing and Supply Agreements

The Company has a License, Supply and Contract Manufacturing Agreement (as amended, the “Supply Agreement”) with Synerx Pharma, LLC and Mylan Teoranta for the supply of melphalan provided in the HEPZATO KIT. An amendment to the Supply Agreement was entered into on April 22, 2024, and effective as of May 1, 2024, which extends the term of the agreement through December 31, 2028, with an option to renew for successive five-year periods upon the mutual written consent of both parties. Although the Supply Agreement does not contain an annual minimum purchase quantity, the Agreement requires Delcath to order full lots of labeled melphalan vials. As of June 30, 2026, the Company has purchased $1.7 million of melphalan under this Supply Agreement in 2026, which is recorded in Accounts Payable in the current Condensed Consolidated Balance Sheet.

Agreements Relating to Clinical Trial Support

The Company has engaged Precision for Medicine LLC (“PfM”) a Clinical Research Organization (“CRO”) to support the Company’s Phase 2 clinical trials evaluating HEPZATO in combination with standard of care in patients with liver dominant mCRC and HER2-negative mBC. In addition to the CRO engagement, the Company has also contracted with other vendors, including those relating to data management as well as clinical trial sites as the studies progress. Deposits totaling $2.4 million have been made by the Company in connection with these engagements that are to be applied to future payments due under the service agreements.

(13)Fair Value Measurements

The Company’s fair value measurements are classified and disclosed in one of the following three categories:

•Level 1: Unadjusted quoted prices in active markets that are accessible at the measurement date for identical, unrestricted assets or liabilities;

•Level 2: Quoted prices in markets that are not active, or inputs which are observable, either directly or indirectly, for substantially the full term of the asset or liability;

•Level 3: Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable (i.e., supported by little or no market activity).

The table below presents activity within Level 3 of the fair value hierarchy, our liabilities carried at fair value relating to the medac settlement, for the six months ended June 30, 2026:

Contingent liabilities are re-measured to fair value each reporting period using projected financial targets, discount rates, probabilities of payment, and projected payment dates.

Significant unobservable inputs in the valuation include:

•Probability of payment:100%

•Discount rate:3.75%

•Timing of expected payments:1 -2 years

Projected contingent payment amounts are discounted back to the current period using a discounted cash flow model. Projected financial targets are based on the Company’s most recent internal operational budgets and may take into consideration alternate scenarios that could result in more or less profitability for the respective service line. Increases or decreases in projected financial targets and probabilities of payment may result in significant changes in the fair value measurements. Increases in discount rates and the time to payment may result in lower fair value measurements. Increases or decreases in any of those inputs in isolation may result in immaterially lower or higher fair value measurement.

The following tables present information about the Company’s financial assets and liabilities that have been measured at fair value as of June 30, 2026 and December 31, 2025 and indicate the fair value hierarchy of the valuation inputs utilized to determine such fair value.

(14)Segment Information

The Company operates its business primarily in the United States and Europe on a consolidated basis inone reportable segment - the research, development, manufacture and distribution of hepatic delivery systems for the use in the treatment of specific conditions (the “reportable segment”). The Company’s chief operating decision maker (“CODM”) is comprised of a single management team consisting of the Chief Financial Officer, Chief Operating Officer, Chief Medical Officer and General Manager that reports to the Chief Executive Officer. The CODM uses consolidated gross profit and net income or loss, which can be found on the Condensed Consolidated Statements of Operations and Comprehensive Income, to assess financial performance. These financial metrics are used to monitor budget versus actual results. Significant segment expenses reviewed by the CODM are presented in the Company’s Condensed Consolidated Statements of Operations and Comprehensive Income. The measure of segment assets provided to the CODM is reported on the balance sheet as total consolidated assets.

Revenues from external customers are attributed to geographies based on the location of the customer. The following table shows the disaggregated revenue by geography for the three and six months ended June 30, 2026 and 2025. No individual foreign country is material to the consolidated results.

As of June 30, 2026 and 2025, substantially all of the Company’s long-lived assets were located in the United States; long-lived assets located in any individual foreign country were not material.

(15)Subsequent Events

The Company has evaluated subsequent events for adjustment to or disclosure in these condensed consolidated financial statements through the date of this report and has not identified any recordable or disclosable events not otherwise reported in these financial statements or the notes thereto.