Delcath Systems, Inc. (Nasdaq: DCTH), an interventional oncology company focused on the treatment of primary and metastatic cancers of the liver, today announced the publication of two investigator-initiated trials-in-progress abstracts on May 21, 2026. These abstracts will be presented at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago. The abstracts highlight ongoing clinical investigations evaluating the use of Delcath’s percutaneous hepatic perfusion (PHP) with melphalan using the HEPZATO KIT™ Hepatic Delivery System (HDS) in metastatic melanoma involving the liver — a common and difficult-to-treat site of disease progression.

One abstract, titled "Phase 2 sequential treatment of percutaneous hepatic perfusion with melphalan/hepatic delivery system followed by tebentafusp in the treatment of metastatic uveal melanoma," describes an investigator-initiated Phase 2 trial evaluating sequential treatment with HEPZATO followed by tebentafusp in patients with metastatic uveal melanoma (mUM) who are HLA-A*02:01 positive and have isolated or liver-dominant metastases. The study is designed to assess progression-free survival and additional measures including safety, objective response, overall survival, and biomarker analyses. The study opened for enrollment in November 2025.

A second abstract, titled "Phase 1b/2 trial of melphalan-percutaneous hepatic perfusion (PHP) therapy and nivolumab/relatlimab in patients with metastatic melanoma and liver metastasis," outlines a single-center Phase 1b/2 study evaluating HEPZATO in combination with nivolumab/relatlimab as a first-line treatment approach for patients with metastatic non-uveal melanoma involving the liver. The trial is intended to assess safety, tolerability, and preliminary efficacy, with secondary objectives including disease control rate, progression-free survival, overall survival, duration of response, and tumor reduction. The study opened for enrollment in January 2026.

The abstract on sequential PHP followed by tebentafusp in mUM (Abstract TPS9605) and the abstract on PHP plus nivolumab/relatlimab in metastatic melanoma with liver metastasis (Abstract TPS9600) will be presented as posters at the 2026 ASCO Annual Meeting. Specific session details will be available on the ASCO website.

“We believe the publication of these two ASCO abstracts underscores the growing clinical interest in HEPZATO’s potential across multiple metastatic melanoma settings with liver involvement,” said Gerard Michel, Chief Executive Officer of Delcath Systems. “These investigator-initiated trials will provide important insights into combining or sequencing liver-directed therapy with modern systemic treatments in patients with challenging disease. We remain committed to supporting such research to advance therapeutic options for patients with liver cancers and metastases.”

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 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 Hepatic Delivery System (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 HEPZATO KIT.

In Europe, the device-only configuration of the HDS is regulated as a Class III 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.

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