General	6 Months Ended
Jun. 30, 2026
Accounting Policies [Abstract]
General	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 Delcath six 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 and one 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 for two 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.

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.

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 Delcath six 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 and one for doxorubicin in the treatment of patients with hepatocellular carcinoma).

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 for two 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.

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.

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.

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.

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.

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.