CHOPIN uveal melanoma trial data in Lancet boosts Delcath (Nasdaq: DCTH)

Rhea-AI Filing Summary

Delcath Systems filed an 8-K to share that full results from the investigator-initiated Phase 2 CHOPIN trial in metastatic uveal melanoma have been published in The Lancet Oncology. The study tested percutaneous hepatic perfusion (PHP) with Delcath’s CHEMOSAT Hepatic Delivery System alone or combined with ipilimumab and nivolumab in 76 patients.

The company highlights that combining PHP with dual immunotherapy more than tripled the 1-year progression-free survival rate and nearly doubled the 2-year overall survival compared with PHP alone, while also improving liver disease control and depth of response. Safety trade-offs were notable: grade 3 or higher treatment-related adverse events occurred in 82% of patients in the combination arm versus 41% in the PHP-alone arm, with one treatment-related death reported, though most events were described as manageable and without new safety signals.

Delcath frames these data as reinforcing the clinical value of its liver-directed PHP platform (HEPZATO KIT/CHEMOSAT) for metastatic uveal melanoma and as a rationale to explore this approach in other liver-dominant cancers, while also reiterating extensive forward-looking risk factors around commercialization, reimbursement, supply chain, and regulatory oversight.

Insights

Oncology & biotech analyst

Phase 2 data publication strengthens clinical narrative but keeps efficacy–toxicity trade-off in focus.

The CHOPIN trial publication in The Lancet Oncology gives Delcath’s PHP plus ipilimumab/nivolumab combination high scientific visibility. Reported benefits include more than tripled 1-year progression-free survival and nearly doubled 2-year overall survival versus PHP alone in metastatic uveal melanoma.

However, the regimen carries substantially higher toxicity: grade 3 or worse treatment-related events in 82% of combination patients versus 41% with PHP alone, and one treatment-related death, though most events were described as manageable and without new safety signals. These factors are central to real-world adoption decisions.

Because this is a single-centre, randomized phase 2 trial with 76 patients, it primarily supports biological plausibility and physician awareness rather than immediately changing regulatory status. Any future impact on HEPZATO KIT and CHEMOSAT use will depend on treating centres’ interpretation of this efficacy–safety balance and on subsequent clinical and commercial updates in Delcath’s periodic filings.

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): March 3, 2026

DELCATH SYSTEMS, INC.

(Exact Name of Registrant as Specified in its Charter)

Delaware		001-16133		06-1245881
(State or other jurisdiction of incorporation or organization)		(Commission File Number)		(IRS Employer Identification No.)

566 Queensbury Avenue

Queensbury, NY 12804

(Address of principal executive offices) (Zip Code)

(212) 489-2100

(Registrant’s telephone number, including area code)

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading symbol(s)		Name of each exchange on which registered
Common Stock, $.01 par value		DCTH		The Nasdaq Capital Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (17 CFR §230.405) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01 Other Events.

CHOPIN Study

On March 3, 2026, Delcath Systems, Inc. issued a press release announcing publication of CHOPIN clinical trial results in the Lancet Oncology. A copy of the press release is furnished as Exhibit 99.1.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.		Description
99.1		Press Release (CHOPIN Clinical Trial Results in The Lancet Oncology), dated March 3, 2026.
104		Cover Page Interactive Data File (embedded within the Inline XBRL document).

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

				DELCATH SYSTEMS, INC.
Date: March 3, 2026				By:		/s/ Gerard Michel
				Name:		Gerard Michel
				Title:		Chief Executive Officer

Exhibit 99.1

Delcath Systems Announces Publication of

CHOPIN Clinical Trial Results in The Lancet Oncology

Publication Highlights Promise of Combined Percutaneous Hepatic Perfusion and

Immunotherapy in Metastatic Uveal Melanoma

QUEENSBURY, NY – March 3, 2026 Delcath Systems, Inc. (Nasdaq: DCTH), (“Delcath” or the “Company”) an interventional oncology company focused on the treatment of primary and metastatic liver cancers, today announced the publication of the full results from the investigator-initiated CHOPIN randomized Phase 2 clinical trial, led by Principal Investigator Professor Ellen Kapiteijn, MD, from Leiden University Medical Center’s Department of Medical Oncology. The publication, titled “Percutaneous hepatic perfusion combined with ipilimumab and nivolumab for metastatic uveal melanoma (CHOPIN): a single-centre, open-label, randomised, phase 2 trial” is published in The Lancet Oncology and presents detailed analyses from the trial, building on the positive topline results previously presented at the European Society for Medical Oncology (ESMO) Congress in October 2025. The link to the article can be found at: https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(25)00720-X/abstract

“The detailed analyses in this publication reinforce the synergistic potential of combining PHP with immunotherapy, showing not only superior PFS and OS but also enhanced hepatic control and deeper, more durable responses. This approach represents a significant advancement for patients with this challenging disease, where liver-dominant metastases drive poor outcomes,” said Professor Ellen Kapiteijn, MD, Principal Investigator and Lead Author from Leiden University Medical Center’s Department of Medical Oncology.

“The full publication in The Lancet Oncology validates the impressive efficacy of combining our liver-directed PHP therapy with immune checkpoint inhibition,” said Gerard Michel, Chief Executive Officer of Delcath Systems. “By more than tripling the 1-year progression-free survival rate and nearly doubling the 2-year overall survival, these results strongly underscore the clinical value of this combination and give us even greater confidence in adoption by treating physicians and patients. We are also encouraged by the potential to explore this paradigm in other liver-dominant cancers.”

The CHOPIN trial randomized 76 patients with metastatic uveal melanoma (mUM; n=38 per arm) to percutaneous hepatic perfusion (PHP) with melphalan using Delcath’s CHEMOSAT^® Hepatic Delivery System (HDS) alone or in combination with ipilimumab plus nivolumab. In both arms patients received two PHP treatments (weeks 1 and 7). In the combination arm patients also received ipilimumab (1 mg/kg) plus nivolumab (3 mg/kg) in weeks 0, 3, 6, and 9, with no maintenance therapy.

Key results (intention-to-treat population):

• Primary endpoint – 1-year progression-free survival (PFS): 54.7% vs 15.8% (adjusted HR 0.34 [95% CI 0.19–0.60]; p=0.0002), Median PFS: 12.8 months vs 8.3 months

• Overall Survival (OS): Median 23.1 months vs 19.6 months (HR 0.39 [95% CI 0.20–0.77]; p=0.0065) 2-year OS: 49.6% vs 22.1%

• Objective Response Rate (ORR): 76.3% vs 39.5% Complete response (CR) rate: 13% vs 3%

Safety

Grade 3 or higher treatment-related adverse events occurred significantly more frequently in the combination arm (82%) than in the PHP-alone arm (41%); p=0.0006. The rate in the combination arm was similar to that reported in the FOCUS trial (81%). The most common grade 3/4 events were thrombocytopenia (34% vs 14%), leukopenia (26% vs 14%), g-glutamyl transferase increase (18% vs 8%), and anemia (13% vs 3%). Most events were self-limiting or manageable with standard supportive care; no new safety signals were identified. One treatment-related death (immune-related triple M syndrome) occurred in the combination arm.

Overall, the authors conclude that the combination of PHP with ipilimumab and nivolumab offers a promising new approach for patients with metastatic uveal melanoma.

About Delcath Systems, Inc., HEPZATO KIT, and CHEMOSAT

Delcath Systems, Inc. is an interventional oncology company focused on the treatment of primary and metastatic liver cancers. The company’s proprietary products, HEPZATO KIT (HEPZATO (melphalan) for Injection/Hepatic Delivery System) and CHEMOSAT Hepatic Delivery System (HDS) for Melphalan percutaneous hepatic perfusion (PHP), are designed to administer high-dose chemotherapy to the liver while controlling systemic exposure and associated side effects during a PHP procedure.

In the United States, HEPZATO KIT is considered a combination drug and device product and is regulated and approved for sale as a drug by the FDA. HEPZATO KIT is comprised of the chemotherapeutic drug melphalan and Delcath’s proprietary HDS. The HDS is used to isolate the hepatic venous blood from the systemic circulation while simultaneously filtrating hepatic venous blood during melphalan infusion and washout. The use of the HDS results in loco-regional delivery of a relatively high melphalan dose, which can potentially induce a clinically meaningful tumor response with minimal hepatotoxicity and reduce systemic exposure. HEPZATO KIT is approved in the United States as a liver-directed treatment for adult patients with metastatic uveal melanoma (mUM) 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. Please see the full Prescribing Information, including BOXED WARNING for the HEPZATO KIT.

In Europe, the device-only configuration of the HDS is regulated as a Class Ill medical device and is approved for sale under the trade name CHEMOSAT Hepatic Delivery System for Melphalan, or CHEMOSAT, where it has been used in the conduct of percutaneous hepatic perfusion procedures at major medical centers to treat a wide range of cancers of the liver.

Forward-Looking Statements

The Private Securities Litigation Reform Act of 1995 provides a safe harbor for forward-looking statements made by Delcath or on its behalf. This press release contains forward-looking statements, including statements regarding the possible synergy seen in the successful Phase 2 CHOPIN Trial being transferable to other cancers with liver-dominant disease; statements regarding the potential of CHEMOSAT Hepatic Delivery System and HEPZATO KIT to improve outcomes for patients with metastatic uveal melanoma and other cancers with liver-dominant disease; statements regarding the potential to drive increased adoption of HEPZATO KIT; statements regarding Delcath’s commitment to raising awareness of the innovative approach taken in the CHOPIN Trial, and accelerating the referral of patients to treatment sites; and statements regarding Delcath’s continued growth and leadership in liver-directed oncology, which are subject to certain risks and uncertainties, that can cause actual results to differ materially from those described. The words “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “should,” “target,” “will,” “would” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Factors that may cause such differences include, but are not limited to, uncertainties relating to: the Company’s commercialization plans and its ability to successfully commercialize the HEPZATO KIT; contributions to adjusted EBITDA; the Company’s successful management of the HEPZATO KIT supply chain, including securing adequate supply of critical components necessary to manufacture and assemble the HEPZATO KIT; successful FDA inspections of the facilities of the Company and those of its third-party suppliers/manufacturers; the Company’s successful implementation and management of the HEPZATO KIT Risk Evaluation and Mitigation Strategy; the potential benefits of the HEPZATO KIT as a treatment for patients with primary and metastatic disease in the liver; the Company’s ability to obtain reimbursement for the HEPZATO KIT; and the Company’s ability to successfully enter into any necessary purchase and sale agreements with users of the HEPZATO KIT. For additional information about these factors, and others that may impact the Company, please see the Company’s filings with the Securities and Exchange Commission, including those on Forms 10-K, 10-Q, and 8-K. However, new risk factors and uncertainties may emerge from time to time, and it is not possible to predict all risk factors and uncertainties. Accordingly, you should not place undue reliance on these forward-looking statements, which speak only as of the date they are made. We undertake no obligation to publicly update or revise these forward-looking statements to reflect events or circumstances after the date they are made.

This release contains forward-looking statements, including statements regarding the expected release of clinical trial results, which are subject to risks and uncertainties. Factors that could affect these forward-looking statements include, but are not limited to, delays in the presentation of the data, or other unforeseen issues relating to the release of the clinical trial results. For a detailed discussion of these and other risks, please refer to Delcath’s filings with the SEC.

Investor Relations Contact:

ICR Healthcare

investorrelations@delcath.com

FAQ

What did Delcath Systems (DCTH) announce in this 8-K filing?

Delcath Systems announced that full results from the Phase 2 CHOPIN trial in metastatic uveal melanoma were published in The Lancet Oncology, detailing outcomes of its liver-directed PHP therapy alone and combined with ipilimumab and nivolumab.

What is the CHOPIN clinical trial mentioned by Delcath Systems (DCTH)?

CHOPIN is a single-centre, open-label, randomized Phase 2 trial in 76 metastatic uveal melanoma patients, comparing Delcath’s percutaneous hepatic perfusion using its CHEMOSAT Hepatic Delivery System alone versus the same PHP combined with ipilimumab and nivolumab immunotherapy.

How did combination therapy perform in Delcath’s CHOPIN trial?

The combination of PHP with ipilimumab and nivolumab more than tripled the 1-year progression-free survival rate and nearly doubled the 2-year overall survival versus PHP alone, while also improving hepatic disease control and producing deeper, more durable responses in metastatic uveal melanoma.

What safety profile was reported in the CHOPIN trial for Delcath’s combination therapy?

Grade 3 or higher treatment-related adverse events occurred in 82% of patients receiving PHP plus ipilimumab/nivolumab versus 41% with PHP alone. Common severe events included thrombocytopenia, leukopenia, elevated gamma-glutamyl transferase, and anemia, and one treatment-related death was reported in the combination arm.

How are HEPZATO KIT and CHEMOSAT described in Delcath Systems’ filing?

HEPZATO KIT and CHEMOSAT are proprietary hepatic delivery systems designed to administer high-dose melphalan chemotherapy directly to the liver while limiting systemic exposure. HEPZATO KIT is FDA-approved in the United States for certain adults with metastatic uveal melanoma and unresectable hepatic metastases.

What forward-looking risks does Delcath Systems (DCTH) highlight related to HEPZATO KIT?

Delcath cites risks around commercializing HEPZATO KIT, managing its supply chain, passing FDA inspections, implementing the Risk Evaluation and Mitigation Strategy, obtaining adequate reimbursement, and securing purchase and sale agreements with users, all of which could affect future performance.

Filing Exhibits & Attachments

4 documents

Press Releases

• EX-99.1 EX-99.1 15.0 KB

Other Documents

• EX-101 XBRL TAXONOMY EXTENSION SCHEMA 2.8 KB
• EX-101 XBRL TAXONOMY EXTENSION LABEL LINKBASE 16.8 KB
• EX-101 XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE 10.6 KB