DCTH Delcath Systems Inc

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Exhibit 99.1 Corporate Presentation NASDAQ: DCTH January 2024

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Table of Contents Forward-Looking Statement 3 Investment Summary 4 Unmet Need: Liver-Dominant Cancers 5 HEPZATO KIT™ 8 Metastatic Uveal Melanoma (mUM) 11 FOCUS Trial 16 HEPZATO KIT: Commercialization 20 Reimbursement & Pricing 25 Next Steps: Future Indications 30 References 39 2

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Forward-Looking Statement The Private Securities Litigation Reform Act of 1995 provides a safe harbor for forward- ability to successfully enter into any necessary purchase and sale agreements with looking statements made by the Company or on its behalf. This presentation contains users of the HEPZATO KIT; the timing and results of the Company’s clinical trials; our forward-looking statements, which are subject to certain risks and uncertainties that determination whether to continue a clinical trial program or to focus on other can cause actual results to differ materially from those described. The words alternative indications; the impact of the COVID-19 pandemic or other pandemics on “anticipate,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” the completion of our clinical trials; the impact of the presentations at major medical “plan,” “potential,” “predict,” “project,” “should,” “target,” “will,” “would” and similar conferences and future clinical results consistent with the data presented; expressions are intended to identify forward-looking statements, although not all uncertainties relating to the timing and results of research and development projects; forward-looking statements contain these identifying words. and uncertainties regarding the Company’s ability to obtain financial and other resources for any research, development, clinical trials and commercialization Factors that may cause such differences include, but are not limited to, uncertainties activities. These factors, and others, are discussed from time to time in our filings relating to: the Company’s ability to successfully commercialize the HEPZATO KIT; the with the Securities and Exchange Commission. Company's successful management of the HEPZATO KIT supply chain, including You should not place undue reliance on these forward-looking statements, which securing adequate supply of critical components necessary to manufacture and speak only as of the date they are made. We undertake no obligation to publicly assemble the HEPZATO KIT; successful FDA inspections of the facilities of Delcath and update or revise these forward-looking statements to reflect events or circumstances third-party suppliers/manufacturers; the Company's successful implementation and after the date they are made. management of the HEPZATO KIT Risk Evaluation and Mitigation Strategy; the potential of the HEPZATO KIT as a treatment for patients with primary and metastatic disease in the liver; our ability to obtain reimbursement for commercialized product; the Company’s 3

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Delcath Investment Summary HEPZATO KIT Commercial Opportunity High Penetration • FDA approval for • Ultra orphan pricing • Included in NCCN Guidelines mUM* 8/14/23 • Focused call points • First and only FDA approved • 1Q 2024 US Launch whole-liver directed therapy • US mUM TAM ~$600M Experienced Significant upside beyond Multiple 2024 Catalysts Management Team mUM • Launch • Expertise in commercializing • Strong efficacy signals in • Revenue build high value, specialty multiple other tumor types • CHOPIN enrollment completion products • Unique interventional • Initiate trials in other indications • TheraSphere (BSX) veterans oncology asset * metastatic Uveal Melanoma (mUM) 4

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HIGH UNMET NEED: Liver-Dominant Cancers 5

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Liver-Dominant Cancers: High Incidence with High Unmet Medical Need * US Incidence of Liver-Dominant Cancers Up to (partial set shown) of patients with liver metastases are not amenable to surgical resection % 50,000 80 1 largely due to extensive tumor burden Delcath Opportunity 40,000 • Limited Overall Survival - Unresectable Liver Cancer 30,000 • Liver: Common Site of Metastases 20,000 o Often the life-limiting organ • Limited Effective Systemic Treatments 10,000 o Systemic Therapies: low efficacy o Immuno-oncology agents become less effective in the 0 presence of metastases mUM ICC mBC mNET mPC mCRC HCC *Metastatic Uveal Melanoma (mUM) 1 Reddy S, et al. Isolated hepatic perfusion for patients with liver metastases, Ther Adv Med Oncol. 2014 Jul; 6(4): 180-194. 6

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Current Liver-Directed Therapies MAJORITY OF TREATMENT 3 SIRT (Y90) Trans Arterial Chemo 2 Embolization (TACE) • Beads obstruct blood flow to tumor and elute chemo • Radioactive beads delivered into a portion of the liver • 50-60k treatments and rising per year • 10-15k treatments and rising per year Limitations Many tumors not Tumors recur and Diffuse disease cannot be Neither approved for the imageable and micro- retreatment options limited treated with a tumor-by- treatment of mUM and metastases are common, due to damage to tumor modality (TACE) and lacking substantial high neither TACE or Y90 can vasculature (TACE) and bilobar treatment is quality data set to support treat the entire liver hepatotoxicity (Y90) hepatotoxic (Y90) usage 2 Xu L, T, Funchain P, F, Bena J, F, Li M, Tarhini A, Berber E, Singh A, D: Uveal Melanoma Metastatic to the Liver: Treatment Trends and Outcomes. Ocul Oncol Pathol 2019;5:323-332. doi: 10.1159/000495113. 3 Lane AM, Kim IK, Gragoudas ES. Survival Rates in Patients After Treatment for Metastasis From Uveal Melanoma. JAMA Ophthalmol. 2018 Sep 1;136(9):981- 986. 7

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Percutaneous Hepatic Perfusion (PHP) Effective, Safe & Repeatable Liver-focused Disease Control 1. Isolation Hepatic venous flow is isolated, enabling >6X greater local Isolation concentration of chemo Filtration 2. Saturation Melphalan (chemo) treats micro and macro lesions simultaneously regardless of location in the liver Saturation 3. Filtration Proprietary filters remove greater than 4 85% of chemo from the body 4 Heppt, M, et al. Combined immune checkpoint blockade for metastatic uveal melanoma: a retrospective, multi-center study. J Immunotherap Cancer. 2019 Nov 13;7(1):299. 9

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Indication Statement HEPZATO KIT (melphalan) for Injection/Hepatic Delivery System HEPZATO KIT is 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. • Indicated Patient Population Includes: o No HLA genotype restrictions o Treatment naïve and previously treated patients 10

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Metastatic Uveal Melanoma (mUM) 11

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mUM: Beachhead Market Opportunity • ~2,000 newly diagnosed cases of primary uveal 2 melanoma per year in the US • 50% metastasize with the liver involved in >90% of 5,6 2,3 cases of metastatic disease (1,000 mUM patients) ~50% metastasize • 1-year OS rate of patients with metastatic disease 1,2 to the liver in the liver is 13% 2,7 o median survival ranging from 4 to 15 months 1 Reddy S, et al. Isolated hepatic perfusion for patients with liver metastases, Ther Adv Med Oncol. 2014 Jul; 6(4): 180-194. 2 Xu L, T, Funchain P, F, Bena J, F, Li M, Tarhini A, Berber E, Singh A, D: Uveal Melanoma Metastatic to the Liver: Treatment Trends and Outcomes. Ocul Oncol Pathol 2019;5:323-332. doi: 10.1159/000495113. 3 Lane AM, Kim IK, Gragoudas ES. Survival Rates in Patients After Treatment for Metastasis From Uveal Melanoma. JAMA Ophthalmol. 2018 Sep 1;136(9):981- 986. 5 Krantz BA, et al. Uveal Melanoma: Epidemiology, Etiology, and Treatment of Primary Disease. Clin Ophthalmol. 2017;11:279-289. 6 Eschelman DJ et al. Transhepatic Therapies for Metastatic Uveal Melanoma. Semin Intervent Radiol. 2013;30(1):39-48. 7 Carvajal RD, et al. Metastatic Disease from Uveal Melanoma: Treatment Options and Future Prospects. Br J Ophthalmol. 2017;101(1):38-44. 12

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mUM: Beachhead Market Opportunity 6 • Most patients with mUM die from liver failure • In 50% of mUM patients, the liver is the only site of 5,6 metastasis • Liver-directed treatment achieves better efficacy compared 8 to systemic therapy ~50% metastasize • 55% of patients have no approved systemic treatment 1,2 to the liver option • Most patients treated with multiple lines of therapy 1 Reddy S, et al. Isolated hepatic perfusion for patients with liver metastases, Ther Adv Med Oncol. 2014 Jul; 6(4): 180-194. 2 Xu L, T, Funchain P, F, Bena J, F, Li M, Tarhini A, Berber E, Singh A, D: Uveal Melanoma Metastatic to the Liver: Treatment Trends and Outcomes. Ocul Oncol Pathol 2019;5:323-332. doi: 10.1159/000495113. 5 Krantz BA, et al. Uveal Melanoma: Epidemiology, Etiology, and Treatment of Primary Disease. Clin Ophthalmol. 2017;11:279-289. 6 Eschelman DJ et al. Transhepatic Therapies for Metastatic Uveal Melanoma. Semin Intervent Radiol. 2013;30(1):39-48. 8 Olofsson BR, et al. Isolated Hepatic Perfusion With Melphalan for Patients With Isolated Uveal Melanoma Liver Metastases: A Multicenter, Randomized, Open-Label, Phase III Trial (the SCANDIUM Trial). J Clin Oncol. 2023 Jun 1;41(16):3042-3050 13

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Diffuse/Miliary Metastatic Pattern in mUM Diffuse Disease is Difficult to Treat with Other Liver Directed Options • Solitary liver lesions are often treated with surgery or ablation. • True nature of the disease may only be seen upon visual confirmation. • Radiographically, metastatic Uveal Melanoma can initially present only as focal lesions. • Traditional liver-directed therapy mechanism of action is not optimal if a whole liver treatment is needed. • Whole organ therapy delivers medication to a specific organ then filters out the medication to minimize systemic exposure. Actual patient sent for a liver resection based upon radiographic diagnosis* * Data on File . 14

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Patient Journey MILESTONE MILESTONE Surveillance Decision Metastases Detected Initial Screening • Ophthalmologist/ • Surgical Oncologist Ocular Oncologist Screening frequency Surgical Resection Initial diagnosis & treatment Treatment Decision Surveillance dependent on risk level • Enucleation • Radiation • Higher risk patients (50%) • Photodynamic therapy are screened at a high • Interventional frequency • Medical Oncologist Most patients receive Radiologist Surveillance at Academic both systemic and • Lower risk patients (50%) Liver-directed therapy Center o Ophthalmology liver-directed are screened at a lower o Optometrists therapies frequency o Eye Specialist • Medical Oncologist • Medical Oncologist Gene expression profiling Surveillance at Systemic Therapy may occur Nonacademic Center ~2,000 patients ~1,000 patients ~800 patients eligible • Ophthalmologist • Ocular Oncologist Pre-Metastatic | 3-5 years Post-Metastatic 15

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U.S. Registration Trial for the Treatment of Patients with mUM 16

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FOCUS TRIAL 9 Summary of Efficacy Results Endpoints HEPZATO KIT (N=91) ORR, n 33 (36.3%) DOR, Median in months 14.0 DCR, n 67 (73.6%) PFS, Median in months 9.0 OS, Median in months 20.53 • Full analysis with final data cut pending publication • HEPZATO Tx every 6-8 weeks up to a maximum of 6 cycles • Prescribing Information includes ORR, DOR and response categories • Trial powered to show an ORR advantage over a meta-analysis of Best Alternative Care o Checkpoint inhibitors, chemotherapy, other liver-directed therapy • Lower bound of FOCUS ORR (26.4%) is significantly higher than the upper bound of the meta-analysis (8.3%) 9 DOI: 10.1200/JCO.2022.40.16_suppl.9510 Journal of Clinical Oncology 40, no. 16_suppl (June 01, 2022) 9510-9510. 17

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FOCUS TRIAL * Published mUM Prospective and Retrospective Studies Median OS Median PFS Clinical Study/Publication Study Type Treatment N 1 year OS (months) (months) AL FOCUS Single-Arm HEPZATO 91 20.53 80% 9.03 systemic and liver- 10 Khoja et al 2019 Meta-Analysis 912 10.2 NA 3.3 directed therapies systemic and liver- 11 Rantala et al 2019 Meta-Analysis 2,494 12.84 NA NA directed therapies 12 TN Piulats et al 2021 Single-Arm ipi plus nivo 52 12.7 NA 3.0 13 AL Heppt et al 2019 Single-Arm ipi plus (pembro or nivo) 64 16.1 NA 3.0 TN tebentafusp 252 21.7 73% 3.3 14 Nathan et al 2021 Randomized TN control 126 16 59% 2.9 TN = Treatment Naïve, AL = Any Line Ipi = ipilimUMab, nivo = nivolumab, pembro = pemUMab *Studies from 2019 or later with >50 patients 10 Khoja L, et al. Meta-analysis in metastatic uveal melanoma to determine progression free and overall survival benchmarks: an international rare cancers initiative (IRCI) ocular melanoma study. Ann Oncol 2019 Aug 1, 30(8): 1370-1380. 11 Ranjala, E, et al. Overall survival after treatment for metastatic uveal melanoma: a systematic review and meta-analysis. Melanoma Res. 2019 Dec; 29(6): 561–568 12 Piulats, J, et al. Nivolumab Plus Ipilimumab for Treatment-Naïve Metastatic Uveal Melanoma: An Open-Label, Multicenter, Phase II Trial by the Spanish Multidisciplinary Melanoma Group (GEM-1402). Journal of Clinical Oncology 39, no. 6 (February 20, 2021) 586-598. 13 Heppt, M, et al. Combined immune checkpoint blockade for metastatic uveal melanoma: a retrospective, multi-center study. J Immunotherapy Cancer. 2019 Nov 13;7(1):299. 14 Nathan, P, et al. Overall Survival Benefit with Tebentafusp in Metastatic Uveal Melanoma. N Engl J Med 2021; 385:1196-1206 18

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FOCUS TRIAL Adverse Events Adverse Reactions (N=95) >10% ALL GRADES (%) GRADES 3 OR 4 (%) Hypotension 13 3 Dyspnea 23 2 Abdominal Pain 39 1 Diarrhea 17 1 Musculoskeletal Pain 46 1 Hemorrhage 15 1 Nausea 57 0 Vomiting 35 0 Fatigue 65 0 Pyrexia 16 0 Groin Pain 11 0 • Most hematological side effects result Cough 15 0 from melphalan Headache 19 0 Lethargy 12 0 • Side effect profile similar to standard melphalan use Dizziness 11 0 Contusion 17 0 Decreased appetite 16 0 Adverse reactions are described further in the HEPZATO KIT PI. 19

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FOCUS TRIAL Adverse Reactions Related to Study Treatment Occurring in ≥10% of Patients (N=95) ALL GRADES (%) GRADES 3 OR 4 (%) Adverse Events Thrombocytopenia* 64 55 Leukopenia* 44 34 Anemia* 61 33 Neutropenia* 35 29 International normalized ratio increased 29 8 Activated partial thromboplastin time prolonged 26 8 Aspartate aminotransferase increased 27 3 Hypocalcemia 12 3 Blood bilirubin increased 11 3 Alanine aminotransferase increased 31 2 Blood alkaline phosphatase increased 25 2 Troponin I increased 12 2 Abdominal pain upper 18 1 Dyspnea 11 1 Nausea 47 0 Fatigue 43 0 Vomiting 27 0 Contusion 16 0 • Most hematological side effects result Asthenia 13 0 Back pain 13 0 from melphalan Decreased appetite 13 0 Abdominal pain 12 0 • Side effect profile similar to standard Lethargy 12 0 melphalan use Groin pain 11 0 Headache 11 0 * Anemia includes anemia, febrile bone marrow aplasia, hemoglobin decreased, normochromic normocytic anemia, red blood cell count decreased. Leukopenia includes leukopenia, lymphocyte count decreased, lymphopenia, and white Adverse reactions are described further in the HEPZATO KIT PI. blood cell count decreased. Neutropenia includes neutropenia and neutrophil count decreased. Thrombocytopenia includes thrombocytopenia and platelet count decrease. 20

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HEPZATO KIT: Commercialization 21

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Delivering an Innovative Treatment with a Well-Trained Team Treatment with HEPZATO KIT involves training and a team approach. The team members below complete a preceptorship and proctorship as well as a risk evaluation and mitigation strategy (REMS) training. Interventional radiologist leads and performs the vascular interventional procedure Perfusionist establishes, monitors, and controls the extracorporeal pump and veno- venous bypass circuit Anesthesiologist manages sedation, analgesia, and respiratory and cardiovascular support All REMS materials are available at www.HEPZATOKITREMS.com or by calling the REMS Coordinating Center at 1-833-632-0457. 22

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Referring Centers HEPZATO Medical Medical Specialized, Targeted Sales Treating Center Oncologist Oncologist Teams Trained Treating Team Three Complementary Teams of Representatives: Perfusionist Interventional Radiologist Clinical Specialists Anesthesiologist Liver-Directed Therapy Representatives Medical Medical Oncologist Medical Ocular Oncologist Oncologist Oncologist Oncology Managers Medical Medical Oncologist Oncologist Medical Oncologist 23

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CENTER CITY STATE Treatment Sites FULLY TRAINED Duke University Durham NC Interest from 20+ sites Moffitt Cancer Center Tampa Bay FL Ohio State University Columbus OH • Focused on a subset of sites to ensure we University of Tennessee Memphis TN achieve our planned activation targets throughout the year PENDING PROCTORSHIP Mayo Clinic Jacksonville Jacksonville FL Stanford University Stanford CA Thomas Jefferson University Philadelphia PA University of California, Los Angeles Los Angeles CA PENDING PRECEPTORSHIP St. John (Cedars) Los Angeles CA University of Wisconsin Madison WI STRONG INTEREST/COMMITMENT Cleveland Clinic Cleveland OH Emory University Atlanta GA Honor Health Scottsdale AZ Massachusetts General Hospital Boston MA Memorial Sloan Kettering New York NY Piedmont Healthcare Atlanta GA University of Miami Miami FL Fully Trained Pending Preceptorship University of Washington Fred Hutchinson Cancer Center Seattle WA Pending Proctorship Strong Interest/Commitment Status as of January 2024 24

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Demonstrated Demand for FDA Approved Treatment in mUM KIMMTRAK • $42.1 million in Q3 2023 US sales ($168M annualized revenue) • Captured an estimated 40% share of eligible patients within 12 months • Approximately 360* patients are eligible for KIMMTRAK KIMMTRAK U.S. Quarterly Sales (USD) • Only 45%* of mUM patients are eligible for treatment due to HLA restriction HEPZATO KIT: FDA Approved August 14, 2023 to Treat Patients with Liver-Dominant mUM • Approximately 800 patients potentially eligible for treatment • HEPZATO has no HLA genotype restrictions KIMMTRAK • Patients often receive both systemic and liver-directed treatment • Only FDA approved drug for 100% of all mUM patients, with appropriate liver involvement *Due to HLA genotype restrictions 25

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HEPZATO KIT: Reimbursement & Pricing 26

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Reimbursement Medicare Patients Private Payer Patients • Follow Medicare guidelines • C-Code and J-Code under review and expected 2024 H1 o For rare disease o Patients to be treated as outpatients • Majority of patients will be outpatient • Medical Prior-Authorization of patients likely required o Drug directly covered by o Delcath has engaged a hub service to assist with benefit Medicare as pass through verification and navigation​ • Centers of Excellence (Prospective Payment System (PPS) exempt and NCI designated Cancer Centers) have the leverage to negotiate favorable rates and reimbursement terms o ~50% of target sites are PPS exempt or NCI Cancer Centers 27

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PHP is Already Part of Current NCCN Guidelines for mUM NCCN Guidelines Version 1.2023 Melanoma: Uveal TREATMENT OF METASTATIC DISEASE WORKUP Clinical trial, if available Clinical Trial (preferred) No evidence of or Observation 99 OR • Biopsy if clinically appropriate disease (Follow-up, UM-4) Consider on or more of the following: ii • Imaging for baseline staging and to ii Distant Imaging to assess mm evaluate specific signs and • Systemic therapies Metastatic response or symptoms • Liver-directed therapies Disease progression • HLA-A*02:01 testing • Regional isolation perfusion of the liver • Consider LFTs, including lactate n • Embolization (chemotherapy, radiation, immunotherapy) II Residual or dehydrogenase (LDH) • Ablative procedures (thermal ablation, chryotherapy) II n progressive • Consider alkaline phosphatase Consider resection and/or RT (photon beam or SRS) for limited II or symptomatic disease of the liver disease • Best supportive/palliative care SOURCE: National Comprehensive ® Cancer Network Regional Isolation Perfusion Methods include isolated hepatic infusion (IHP), percutaneous hepatic perfusion (PHP), HAI, and embolization techniques. PHP is a simpler, less invasive alternative to IHP that can be repeated. It uses a double-balloon catheter inserted into the inferior vena cava to isolate hepatic venous blood that is then filtered extracorporeally. 28

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Components of Hospital Reimbursement Assuming Outpatient Pass Through Status with C-Code DRUG HEALTHCARE FACILITY FEE “PHYSICIAN” PAYMENT • MDs primarily on salary but physician payments • ASP+6% (CMS) • The existing CPT codes should capture all and associated RVUs are still relevant steps of the procedure • Likely similar for commercial • The existing CPT codes should capture all steps • Believe the existing codes will provide payers of the procedure payment competitive with other • Believe the existing codes will provide payment interventional procedures competitive with other interventional procedures CPT Code mapping complete No meaningful impact on treatment decisions 29

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HEPZATO KIT Pricing Consistent with Only Other Approved mUM Therapy At First Assessment (first time to discontinue treatment because of progression) DRUG DOSE COST* TREATMENTS #** TOTAL COST KIMMTRAK $19,289 24 $462,936 HEPZATO $182,500 2 $365,000 Mean HEPZATO treatment vs. mean treatment duration of KIMMTRAK (per pivotal trials) DRUG DOSE COST* MEAN TREATMENTS #*** TOTAL COST KIMMTRAK $19,289 41 $790,849 HEPZATO $182,500 4.1 $748,250 *Dose Cost ASP calculated using 7/2023 CMS payment allowance limit ** Minimum treatments prior to determining progression based on trial protocols *** Mean from published phase 3 trials 30

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NEXT STEPS: Future Indications 31

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Clinical Rationale for Broad Development Effort Melphalan has demonstrated clinical activity in multiple tumor types Promising ORR, DCR and PFS signals seen across multiple tumor types with CHEMOSAT in Europe and in earlier studies with IHP In many solid tumor patients, liver metastases are often life limiting HEPZATO is the only liver-directed treatment that can repeatedly treat the whole liver Potential for significant improvement in survival Converting unresectable liver metastases into resectable metastases and adjuvant usage to prevent recurrence Potential for sequential usage with Immune-Oncology (I/O) agents Liver metastases reduce I/O therapy efficacy due to the tumor microenvironment inducing immune tolerance, HEPZATO may reduce this effect 32

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Strong Correlation of IHP and PHP Efficacy in mUM Patients IHP activity in CRC and NET 15 IHP / Melphalan in mCRC Meta-analysis of 8 mUM clinical studies N=154 ORR 50% 16 Endpoint IHP (%) PHP (%) Van Iersel mPFS 7.4 months mOS 24.8 months mOS 17.1 17.3 N=120 ORR 61% 17 Alexander mOS 17.4 months mPFS 7.2 9.6 2-year survival 34% hPFS 10 9.5 IHP in mNET Complications 39.1 23.8 ORR 50% DOR 15 months 18 Grover mhPFS 7 months Mortality 5.5 1.8 mOS 48 months IHP, or Intrahepatic Perfusion, is an invasive surgical technique for delivering high doses of chemotherapy to the liver; procedure related mortality and morbidity prevented common usage. PHP is a minimally invasive, safer procedure which accomplishes the same goals as IHP and can be performed up to 6 times. 15 Bethlehem MS et al. Meta-Analysis of Isolated Hepatic Perfusion and Percutaneous Hepatic Perfusion as a Treatment for Uveal Melanoma Liver Metastases. Cancers (Basel). 2021 Sep 21;13(18):4726. 16 Van Iersel LB, Gelderblom H, Vahrmeijer AL, et al. Isolated hepatic melphalan perfusion of colorectal liver metastases: outcome and prognostic factors in 154 patients. Ann Oncol. 2008;19:1127–34Grover A et al. Isolated Hepatic Perfusion with 200 mg Melphalan for Advanced Noncolorectal Liver Metastases. Surgery. (2005). 136. 1176-82. 17 Alexander HR Jr, Bartlett DL, Libutti SK, et al. Analysis of factors associated with outcome in patients undergoing isolated hepatic perfusion for unresectable liver metastases from colorectal center. Ann Surg Oncol. 2009;16:1852–9 18 Grover AC, Libutti SK, Pingpank JF, Helsabeck C, Beresnev T, Alexander HR. Isolated hepatic perfusion for the treatment of patients with advanced liver metastases from pancreatic and gastrointestinal neuroendocrine neoplasms. Surgery. 2004;136(6):1176- 1182. doi:https://doi.org/10.1016/j.surg.2004.06.044 33

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Rationale for Combining HEPZATO with IO Therapy Liver Metastases Suppress IO Therapy Efficacy 34

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Encouraging Signal of Efficacy for PHP and I/O Drug Combination From Phase 1b Part of the Chopin Trial % Change of Target Lesions from Baseline by Response Category 19 • N=7 in Phase 1b portion of the trial • RP2D: IPI 1mg/kg and NIVO 3mg/kg. Well tolerated, no DLTs or deaths. • 1CR, 6 PR and 1 PD (85.7% ORR, 100% DCR) – meta-analysis of prior IO trials has shown ORR<<10% • As of 11/15/22 the median follow-up was 29.1 months, the median PFS was 29.1 months, and the median duration of response was 27.1 months. All patients are still alive. • 3 of 4 patients who subsequently experienced PD continued with treatment in the form of repeated Melphalan Chemosat treatments • Ongoing randomized Phase 2 (control is Chemosat) has recruited 50% of N=76 patients and will provide an interim analysis at N=40 patients Ipilimumab + melphalan liver Ipilimumab + Ipilimumab + melphalan liver Ipilimumab + Inclusion nivolumab* chemo-saturation nivolumab* nivolumab* chemo-saturation nivolumab* *c1: 1+1mg/kg, c2: 1+3mg/kg 19 Tong TML et al. Combining Melphalan Percutaneous Hepatic Perfusion with Ipilimumab Plus Nivolumab in Advanced Uveal Melanoma: First Safety and Efficacy Data from the Phase Ib Part of the Chopin Trial. Cardiovasc Intervent Radiol. 2023 Mar;46(3):350- 359. 35

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Market Expansion U.S. TAM Significant Upside >$1B per year 50,000 * U.S. Incidence of Liver-Dominant Cancers 40,000 30,000 20,000 10,000 0 mUM ICC mBC mNET mPC mCRC HCC *Metastatic Uveal Melanoma (mUM) 36

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HEPZATO KIT: Financials and Team 37

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Capital Structure and Share Information DCTH (NASDAQ) Share Listing - Current a. As of September 30, 2023; includes 19.7M of Common plus; 1.1M Preferred E & E-1, 1.5M of Preferred F-2; 4.8M of Preferred F-3; Conversion of convertible notes .5M; & a 28.6M Shares Outstanding 1.0M Pre-funded Warrants as converted. Does not include Tranche B Outstanding Warrants. b $40.5M b. As of September 30, 2023; (10-Q filing on November 13, Cash and Cash Equivalents 2023) which includes $35M received from Tranche A warrants exercised 21 days after receipt of FDA approval c for HEPZATO; 7.8M Warrants Outstanding c. As of September 30, 2023; 3.6M warrants at a $10 exercise price and 4.17M Tranche B warrants for an 4.1M Stock Options Granted aggregate exercise price $25 million exercisable until the earlier of 3/31/2026 or 21 days following recording at least $10 million in quarterly U.S. revenue. d $9.7M 2023 Q3 Cash Burn d. Q3 Net cash used in operating activities e. Includes $5.0M of notes convertible at $11.98 per common e share equivalent, $9.8M Debt f. Used NASDAQ closing price information starting on December 20, 2022 – December 20, 2023 f $2.25 - $7.99 52 week Low – High g. 30-day average calculated between on December 4, 2023 – January 4, 2024 g 351,474 30d Average Daily Volume 38

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Multi-Disciplinary, Experienced Leadership Team Gerard Michel John Purpura BOARD OF DIRECTORS CHIEF EXECUTIVE OFFICER CHIEF OPERATING OFFICER John R. Sylvester Chairman • Past VP and Exec Director roles of Reg. • 30+ yrs. pharma/medtech experience Affairs for Bracco Diagnostics Dr. Roger G. Stoll, Ph.D. Director • C-suite roles at Vericel Corp, Biodel, • Senior roles Sanofi-Aventis, Bolar & NPS Elizabeth Czerepak Director Pharma, Luitpold Pharma & Eon Labs • M.S. Microbiology, B.S. Biology & • M.S. Mgmt.. & Policy and B.S. Chemistry Geology from the Univ. of Rochester Steven Salamon Director and Biology at the State University of NY School of Medicine at Stony Brook Dr. Gil Aharon, Ph.D. Director • M.B.A. Simon School of Business & Leadership Gerard Michel CEO Kevin Muir Sandra Pennell Vojislav Vukovic, MD PhD GENERAL MANAGER, INTERVENTIONAL ONCOLOGY SVP, FINANCE CHIEF MEDICAL OFFICER • 20+ yrs. medtech/bioTx sales & • 20+ years' biotech financial oversight • Oncology dev. exec, global clinical marketing experience experience expertise • Senior leadership roles at BTG, • Manages global financial affairs, U.S. • Former CMO at Aileron, Taiho, Synta ClearFlow, Aragon Surgical, Kensey GAAP compliance • MD, Univ. of Sarajevo | MSc, PhD, Univ. Nash Corporation, and Kyphon • Led finance at Invivyd of Toronto • Field Artillery officer, U.S. Army • VP at Vericel Corp • Published, AACR, ASCO, ASH, ESMO • B.S. in Management Systems member • MSc, Accountancy, Univ. of Illinois Engineering, U.S. Military Academy at West Point 39

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Thank You 40

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References 1. Reddy S, et al. Isolated hepatic perfusion for patients with liver metastases, Ther Adv Med Oncol. 2014 Jul; 6(4): 180-194. 2. Xu L, T, Funchain P, F, Bena J, F, Li M, Tarhini A, Berber E, Singh A, D: Uveal Melanoma Metastatic to the Liver: Treatment Trends and Outcomes. Ocul Oncol Pathol 2019;5:323-332. doi: 10.1159/000495113. 3. Lane AM, Kim IK, Gragoudas ES. Survival Rates in Patients After Treatment for Metastasis From Uveal Melanoma. JAMA Ophthalmol. 2018 Sep 1;136(9):981- 986. 4. Heppt, M, et al. Combined immune checkpoint blockade for metastatic uveal melanoma: a retrospective, multi-center study. J Immunotherap Cancer. 2019 Nov 13;7(1):299. 5. Krantz BA, et al. Uveal Melanoma: Epidemiology, Etiology, and Treatment of Primary Disease. Clin Ophthalmol. 2017;11:279-289 6. Eschelman DJ et al. Transhepatic Therapies for Metastatic Uveal Melanoma. Semin Intervent Radiol. 2013;30(1):39-48. 7. Carvajal RD, et al. Metastatic Disease from Uveal Melanoma: Treatment Options and Future Prospects. Br J Ophthalmol. 2017;101(1):38-44. 8. Olofsson BR, et al. Isolated Hepatic Perfusion With Melphalan for Patients With Isolated Uveal Melanoma Liver Metastases: A Multicenter, Randomized, Open-Label, Phase III Trial (the SCANDIUM Trial). J Clin Oncol. 2023 Jun 1;41(16):3042-3050. 9. DOI: 10.1200/JCO.2022.40.16_suppl.9510 Journal of Clinical Oncology 40, no. 16_suppl (June 01, 2022) 9510-9510. 10. Khoja L, et al. Meta-analysis in metastatic uveal melanoma to determine progression free and overall survival benchmarks: an international rare cancers initiative (IRCI) ocular melanoma study. Ann Oncol 2019 Aug 1, 30(8): 1370- 1380. 11. Ranjala, E, et al. Overall survival after treatment for metastatic uveal melanoma: a systematic review and meta-analysis. Melanoma Res. 2019 Dec; 29(6): 561–568 12. Piulats, J, et al. Nivolumab Plus Ipilimumab for Treatment-Naïve Metastatic Uveal Melanoma: An Open-Label, Multicenter, Phase II Trial by the Spanish Multidisciplinary Melanoma Group (GEM-1402). Journal of Clinical Oncology 39, no. 6 (February 20, 2021) 586-598. 13. Heppt, M, et al. Combined immune checkpoint blockade for metastatic uveal melanoma: a retrospective, multi-center study. J Immunotherapy Cancer. 2019 Nov 13;7(1):299. 14. Nathan, P, et al. Overall Survival Benefit with Tebentafusp in Metastatic Uveal Melanoma. N Engl J Med 2021; 385:1196-1206 15. Bethlehem MS et al. Meta-Analysis of Isolated Hepatic Perfusion and Percutaneous Hepatic Perfusion as a Treatment for Uveal Melanoma Liver Metastases. Cancers (Basel). 2021 Sep 21;13(18):4726. 16. Van Iersel LB, Gelderblom H, Vahrmeijer AL, et al. Isolated hepatic melphalan perfusion of colorectal liver metastases: outcome and prognostic factors in 154 patients. Ann Oncol. 2008;19:1127–34Grover A et al. Isolated Hepatic Perfusion with 200 mg Melphalan for Advanced Noncolorectal Liver Metastases. Surgery. (2005). 136. 1176-82. 17. Alexander HR Jr, Bartlett DL, Libutti SK, et al. Analysis of factors associated with outcome in patients undergoing isolated hepatic perfusion for unresectable liver metastases from colorectal center. Ann Surg Oncol. 2009;16:1852–9. 18. Grover AC, Libutti SK, Pingpank JF, Helsabeck C, Beresnev T, Alexander HR. Isolated hepatic perfusion for the treatment of patients with advanced liver metastases from pancreatic and gastrointestinal neuroendocrine neoplasms. Surgery. 2004;136(6):1176-1182. doi:https://doi.org/10.1016/j.surg.2004.06.044 19. Tong TML et al. Combining Melphalan Percutaneous Hepatic Perfusion with Ipilimumab Plus Nivolumab in Advanced Uveal Melanoma: First Safety and Efficacy Data from the Phase Ib Part of the Chopin Trial. Cardiovasc Intervent Radiol. 2023 Mar;46(3):350-359. 41

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Document and Entity Information	Jan. 05, 2024
Cover [Abstract]
Security Exchange Name	NASDAQ
Amendment Flag	false
Entity Central Index Key	0000872912
Document Type	8-K
Document Period End Date	Jan. 05, 2024
Entity Registrant Name	DELCATH SYSTEMS, INC.
Entity Incorporation State Country Code	DE
Entity File Number	001-16133
Entity Tax Identification Number	06-1245881
Entity Address, Address Line One	1633 Broadway
Entity Address, Address Line Two	Suite 22C
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10019
City Area Code	(212)
Local Phone Number	489-2100
Written Communications	false
Soliciting Material	false
Pre Commencement Tender Offer	false
Pre Commencement Issuer Tender Offer	false
Security 12b Title	Common Stock, $.01 par value
Trading Symbol	DCTH
Entity Emerging Growth Company	false

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