Delcath Shares New Real-World Findings From European Investigators
Delcath Systems an interventional oncology company dedicated to advancing treatments for primary and metastatic liver cancers, announced the presentation of new clinical findings involving percutaneous hepatic perfusion with melphalan (M-PHP) using the CHEMOSAT® Hepatic Delivery System at the ESMO Breast Cancer Congress 2026.
The presentation featured retrospective real-world data collected by independent investigators from three European treatment centers evaluating the safety, feasibility, and clinical activity of M-PHP in patients with liver-dominant metastatic breast cancer. The findings were presented in an electronic poster session during the congress held on May 7, 2026.
The study represents an important addition to the growing body of evidence supporting liver-directed treatment strategies for patients whose breast cancer has spread predominantly to the liver. Investigators focused on a heavily pretreated patient population with limited therapeutic options, highlighting both the challenges and opportunities associated with managing metastatic disease involving the liver.
Presentation Information
The research was presented during the ESMO Breast Cancer Congress 2026 in the e-poster format. The presentation was delivered by Dr. Cornelia Lieselotte Angelika Dewald from Hannover Medical School.
Presentation Details
- Congress: ESMO Breast Cancer Congress 2026
- Date: May 7, 2026
- Session Time: 13:15 local congress time
- Presentation Format: E-poster
- Title: “Safety and Feasibility of Percutaneous Hepatic Perfusion with Melphalan in Patients with Liver-Dominant Metastatic Breast Cancer”
- Presenter: Cornelia Lieselotte Angelika Dewald, MD
- Institution: Hannover Medical School
- Abstract Number: 574eP
Understanding Liver-Dominant Metastatic Breast Cancer
Metastatic breast cancer remains one of the most difficult forms of cancer to manage, particularly when the disease spreads extensively to the liver. Liver metastases can significantly affect patient outcomes because the liver is a vital organ responsible for metabolism, detoxification, nutrient processing, and numerous other physiological functions.
When breast cancer becomes liver-dominant, the progression of disease within the liver can quickly become the primary driver of morbidity and mortality. Patients often experience worsening liver function, increasing tumor burden, fatigue, pain, weight loss, and declining quality of life. In many cases, liver progression also limits the effectiveness or tolerability of systemic therapies.
Traditional treatment approaches for metastatic breast cancer include chemotherapy, endocrine therapy, targeted therapies, immunotherapy, and antibody-drug conjugates. However, despite significant advances in systemic treatment, many patients with liver-dominant disease eventually experience progression after multiple lines of therapy.
This clinical reality has increased interest in liver-directed treatment approaches designed to directly target tumors in the liver while attempting to minimize systemic toxicity. Procedures such as embolization, ablation, and hepatic perfusion have therefore emerged as potential options for carefully selected patients.
What Is Percutaneous Hepatic Perfusion With Melphalan?
Percutaneous hepatic perfusion with melphalan, also referred to as M-PHP, is a specialized liver-directed procedure developed to deliver high-dose chemotherapy directly to the liver. The procedure is designed to maximize drug exposure to liver tumors while reducing systemic exposure through extracorporeal filtration.
The treatment uses melphalan, a well-known chemotherapeutic agent with activity against several cancer types. During the procedure, melphalan is infused directly into the hepatic artery, which supplies blood to the liver. Because liver tumors derive much of their blood supply from the hepatic artery, this approach enables higher concentrations of chemotherapy to reach tumor tissue.
A key component of the procedure involves isolating the venous outflow from the liver and filtering the blood through an extracorporeal hemofiltration system before returning it to the patient’s circulation. This filtration process is intended to reduce systemic exposure to melphalan and limit treatment-related toxicity.
The CHEMOSAT® Hepatic Delivery System serves as the platform enabling this procedure. In the United States, Delcath markets HEPZATO KIT, which combines melphalan for injection with the proprietary delivery system.
Importance of Real-World Data
The retrospective analysis presented at ESMO Breast Cancer Congress 2026 is particularly important because it reflects real-world clinical experience outside the highly controlled setting of a prospective clinical trial.
Real-world evidence can provide valuable insights into how therapies perform across diverse patient populations, treatment centers, and clinical situations. Such data may help clinicians better understand treatment feasibility, procedure-related risks, patient selection considerations, and potential outcomes.
The investigators involved in the study collected and analyzed data from three European centers that had experience using M-PHP in patients with liver-dominant metastatic breast cancer. The analysis sought to evaluate safety, feasibility, and tumor response according to RECIST version 1.1 criteria.
Study Population and Patient Characteristics
The retrospective cohort included 15 patients with liver-dominant metastatic breast cancer treated between September 2015 and May 2024.
These patients represented a heavily pretreated population with advanced disease and limited remaining treatment options. The median number of prior systemic therapy lines was four, with a range from one to six prior treatments.
This level of prior treatment highlights the aggressive nature of metastatic breast cancer and underscores the unmet need for additional therapeutic strategies in patients who continue to experience progression despite multiple standard therapies.
Many patients with advanced metastatic breast cancer undergo several sequential lines of treatment over the course of their disease. While newer therapies have improved survival and disease control for many individuals, resistance eventually develops in a significant proportion of patients.
For patients whose disease becomes concentrated within the liver, treatment decisions become increasingly complex. Progressive liver metastases can compromise liver function, reduce tolerance for additional systemic therapy, and ultimately shorten survival.
Against this backdrop, the exploration of liver-directed approaches such as M-PHP has gained increasing attention among oncologists and interventional specialists.
Treatment Delivery and Procedural Experience
According to the analysis, patients received a median of one M-PHP treatment cycle, although the range extended from one to seven cycles.
The variation in treatment cycles likely reflects differences in patient condition, disease response, treatment tolerance, and physician assessment.
The procedure generally required intensive post-treatment monitoring, with most patients admitted to the intensive care unit for one to two days following treatment.
ICU observation is commonly used after complex interventional oncology procedures to closely monitor hemodynamic status, organ function, and potential complications.
The need for specialized procedural expertise and post-treatment care highlights the complexity of M-PHP and emphasizes the importance of experienced multidisciplinary teams in delivering this therapy.
Such teams may include interventional radiologists, medical oncologists, anesthesiologists, intensive care specialists, oncology nurses, and supportive care providers.
Safety Findings From the Retrospective Analysis
Safety was a major focus of the retrospective evaluation, especially given the intensive nature of M-PHP.
The investigators reported that 67% of patients required blood transfusions, primarily involving packed red blood cells.
Intra-procedural and peri-procedural adverse events occurred in 60% of patients. These events were primarily hematologic or hemodynamic in nature.
Additionally, grade 3 or grade 4 adverse events after the procedure were reported in 80% of patients. The majority of these events involved bone marrow suppression and neutropenic-related infections.
Neutropenia refers to a reduction in neutrophils, which are white blood cells essential for fighting infections. Severe neutropenia can increase susceptibility to serious infections and often requires close monitoring, supportive care, antibiotics, or growth factor support.
Importantly, the analysis noted that these adverse events generally appeared early, with a median onset of one day following the procedure, and typically resolved within a median of seven days.
Although the incidence of serious adverse events was significant, the findings also suggest that many complications were manageable and reversible with appropriate supportive care.
The safety profile observed in the study reflects the intensity of delivering high-dose regional chemotherapy and highlights the need for careful patient selection and experienced clinical management.
Tumor Response Observed in the Liver
One of the most encouraging aspects of the retrospective analysis was the level of hepatic tumor response observed among treated patients.
Investigators reported that nine out of fifteen patients achieved a hepatic partial response, representing 60% of the treated cohort.
Three patients were not evaluable for response.
A partial response under RECIST criteria generally indicates a meaningful reduction in measurable tumor burden. In heavily pretreated metastatic breast cancer patients with liver-dominant disease, such responses may translate into symptom improvement, delayed progression, and potential quality-of-life benefits.
The response rate observed in this small retrospective cohort suggests that M-PHP may have meaningful anti-tumor activity within the liver.
Because liver metastases can become the primary determinant of survival and clinical deterioration, effective control of hepatic disease may represent an important therapeutic goal.
However, the retrospective nature of the study and the limited sample size mean that additional research will be necessary to confirm these findings and better define which patients are most likely to benefit.
Overall Survival Outcomes
The analysis also evaluated overall survival following the first M-PHP treatment.
Investigators reported a median overall survival of 6.0 months from the first M-PHP procedure. The reported 95% confidence interval ranged from 2.9 months to not reached.
The survival range extended from 0.1 months to 76.5 months.
At the time of last follow-up, 33% of patients remained alive.
Median follow-up duration was reported as 55.6 months.
Interpreting survival outcomes in retrospective studies can be challenging due to differences in baseline patient characteristics, disease burden, prior treatments, and follow-up duration.
Nevertheless, the long survival observed in certain patients suggests that some individuals may derive substantial benefit from liver-directed therapy.
Future prospective studies will be important for identifying predictors of response and clarifying the potential survival impact of M-PHP in metastatic breast cancer.
Expert Commentary From Delcath Leadership
Gerard Michel, Chief Executive Officer of Delcath Systems, commented on the significance of the findings and the broader implications for patients with liver-dominant metastatic breast cancer.
According to Michel, the data presented by independent European investigators provide real-world evidence supporting the use of HEPZATO KIT and CHEMOSAT in this difficult-to-treat patient population.
He also emphasized the importance of continued evaluation through additional clinical research.
The company believes these findings reinforce the rationale for further investigation of liver-directed treatment strategies in metastatic breast cancer patients whose disease is concentrated in the liver.
Ongoing Phase 2 Clinical Trial
In addition to the retrospective analysis presented at ESMO Breast Cancer Congress 2026, Delcath noted that HEPZATO KIT is currently being evaluated in a randomized Phase 2 clinical trial involving metastatic breast cancer patients with liver-dominant disease.
The trial, known as PHP-MBC-202, is listed on ClinicalTrials.gov under identifier NCT06875128.
Prospective randomized trials are considered essential for establishing the safety and efficacy of new treatment approaches. Such studies can help determine whether observed benefits are reproducible and clinically meaningful compared with standard treatment options.
The Phase 2 study may also provide additional information regarding patient selection, response durability, progression-free survival, overall survival, and quality-of-life outcomes.
As interest in liver-directed therapies continues to grow, results from prospective clinical trials are expected to play an important role in shaping future treatment strategies.
The Growing Role of Liver-Directed Oncology Therapies
The presentation at ESMO Breast Cancer Congress 2026 reflects a broader trend within oncology toward increasingly personalized and organ-specific treatment approaches.
Historically, metastatic breast cancer has largely been treated with systemic therapies because the disease is considered widespread. However, clinicians increasingly recognize that certain metastatic patterns may benefit from local or regional interventions.
Liver-dominant disease represents one such scenario.
In selected patients, controlling liver metastases may prolong survival, delay organ failure, reduce symptoms, and potentially create opportunities for additional systemic therapy.
Liver-directed therapies continue to evolve and may include:
- Hepatic arterial infusion chemotherapy
- Radioembolization
- Chemoembolization
- Thermal ablation
- Surgical resection
- Stereotactic radiation therapy
- Hepatic perfusion techniques
Each approach carries distinct advantages, limitations, and eligibility criteria.
The emergence of technologies like CHEMOSAT and HEPZATO KIT illustrates the growing integration of interventional oncology with systemic cancer care.
Challenges Associated With Advanced Liver Metastases
Managing liver metastases in metastatic breast cancer remains particularly challenging because of the liver’s critical role in normal physiology.
As tumors progress within the liver, patients may experience:
- Impaired liver function
- Elevated bilirubin levels
- Reduced protein synthesis
- Fatigue and weakness
- Abdominal pain
- Weight loss
- Fluid accumulation
- Reduced tolerance to systemic therapy
In advanced cases, liver failure can become the leading cause of death.
This reality underscores the need for innovative approaches capable of controlling hepatic disease burden.
However, liver-directed procedures must balance therapeutic efficacy against the risk of procedure-related toxicity and complications.
The findings presented at ESMO highlight both the potential anti-tumor activity of M-PHP and the importance of careful safety management.
Need for Further Research
While the retrospective analysis offers encouraging insights, several limitations must be considered.
The study involved a relatively small patient population of fifteen individuals, and retrospective analyses are inherently subject to selection bias and variability in clinical practice.
Additionally, the absence of a control group makes it difficult to compare outcomes directly with alternative treatment strategies.
Further research will therefore be essential to better understand:
- Optimal patient selection criteria
- Timing of therapy
- Combination approaches with systemic treatments
- Long-term survival outcomes
- Quality-of-life impact
- Management of treatment-related toxicities
- Biomarkers predicting response
The ongoing randomized Phase 2 trial may help address some of these questions.
Expanding Interest in Interventional Oncology
Interventional oncology has emerged as one of the fastest-growing subspecialties in cancer treatment.
The field combines imaging-guided procedures with targeted therapeutic delivery methods to treat tumors in a minimally invasive manner.
Advances in catheter-based therapies, imaging technologies, and drug-delivery systems have expanded the range of available interventions for patients with localized or organ-dominant disease.
In liver cancers and liver metastases, interventional oncology procedures may provide:
- Local tumor control
- Symptom relief
- Bridging to other therapies
- Preservation of liver function
- Potential survival benefit in selected patients
The use of M-PHP represents a sophisticated example of regional chemotherapy delivery that seeks to maximize anti-cancer exposure while limiting systemic toxicity.
Implications for Patients and Physicians
For patients with heavily pretreated metastatic breast cancer involving the liver, treatment options can become increasingly limited over time.
The findings presented at ESMO Breast Cancer Congress 2026 suggest that M-PHP may offer a potential treatment strategy for selected individuals with liver-dominant disease.
However, physicians must carefully weigh the potential benefits against the known risks and procedural complexity associated with the therapy.
Because serious adverse events were common in the retrospective analysis, treatment decisions require multidisciplinary evaluation and close supportive care.
Patients considering liver-directed therapies may benefit from consultation at specialized centers experienced in advanced interventional oncology procedures.
The presentation of new data at ESMO Breast Cancer Congress 2026 marks another step in the continued evaluation of liver-directed therapies for metastatic breast cancer.
As researchers seek to improve outcomes for patients with advanced disease, innovative approaches targeting organ-specific progression may become increasingly important.
The retrospective analysis presented by independent European investigators contributes meaningful real-world evidence regarding the feasibility and activity of M-PHP using the CHEMOSAT Hepatic Delivery System.
Although additional research is required, the findings support continued investigation of HEPZATO KIT and related liver-directed strategies in patients with liver-dominant metastatic breast cancer.
With the ongoing Phase 2 trial underway, oncologists and researchers will continue to monitor whether these approaches can ultimately provide durable clinical benefit for patients facing one of the most difficult forms of metastatic disease.
As the oncology community advances toward more individualized treatment paradigms, therapies that directly address dominant sites of metastatic progression may play a growing role in comprehensive cancer care.
For Delcath Systems, the presentation at ESMO Breast Cancer Congress 2026 reflects the company’s ongoing efforts to expand the potential applications of its hepatic delivery technology and contribute to evolving treatment options for patients with advanced cancers involving the liver.
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.
