Perfusion and infusion for melanoma in-transit metastases in the era of effective systemic therapy

Wild-type IDH1 inhibition enhances chemotherapy response in melanoma

BACKGROUND

Alternative treatment strategies in melanoma beyond immunotherapy and mutation-targeted therapy are urgently needed. Wild-type isocitrate dehydrogenase 1 (wtIDH1) has recently been implicated as a metabolic dependency in cancer. The enzyme protects cancer cells under metabolic stress, including nutrient limited conditions in the tumor microenvironment. Specifically, IDH1 generates NADPH to maintain redox homeostasis and produces α-ketoglutarate to support mitochondrial function through anaplerosis. Herein, the role of wtIDH1 in melanoma is further explored.

METHODS

The expression of wtIDH1 was determined by qRT-PCR, and Western blot in melanoma cell lines and the effect of wtIDH1 on metabolic reprogramming in melanoma was interrogated by LC-MS. The impact of wtIDH1 inhibition alone and in combination with chemotherapy was determined in cell culture and mouse melanoma models.

RESULTS

Melanoma patients express higher levels of the wtIDH1 enzyme compared to normal skin tissue, and elevated wtIDH1 expression portends poor patient survival. Knockdown of IDH1 by RNA interference inhibited cell proliferation and migration under low nutrient levels. Suppression of IDH1 expression in melanoma also decreased NADPH and glutathione levels, resulting in increased reactive oxygen species. An FDA-approved inhibitor of mutant IDH1, ivosidenib (AG-120), exhibited potent anti-wtIDH1 properties under low magnesium and nutrient levels, reflective of the tumor microenvironment in natura. Thus, similar findings were replicated in murine models of melanoma. In light of the impact of wtIDH1 inhibition on oxidative stress, enzyme blockade was synergistic with conventional anti-melanoma chemotherapy in pre-clinical models.

CONCLUSIONS

These results demonstrate the clinical potential of wtIDH1 inhibition as a novel and readily available combination treatment strategy for patients with advanced and refractory melanoma. Schematic shows increased wild-type IDH1 expression and activity as an adaptive response to metabolic stress induced by chemotherapy.

Impact of electrochemotherapy in metastatic cutaneous melanoma: a contemporary systematic review and meta-analysis

BACKGROUND

Electrochemotherapy (ECT) harnesses electric pulses to enhance cytotoxic drug delivery into tumors and has entered the armamentarium to treat superficially metastatic melanoma. We performed a systematic review and meta-analysis to assess treatment patterns and patient outcomes.

METHODS

PubMed, Medline, Embase, and the Cochrane Library databases were queried for publication from inception to September 2020. Primary outcome measures were overall and complete response rate (ORR and CRR); secondary outcomes included local control rate (LCR) and overall survival (OS).

RESULTS

Twenty-seven studies met the selection criteria for a total of 1161 individuals (mean age 71 years) and 5308 tumors (weighted mean size 14 mm). The majority of patients (n = 1124) underwent bleomycin-ECT. Aggregate ORR was 77.6% (95% confidence interval [CI] 71.0 - 83.2%) and CRR 48% (95% CI 42 - 54%), with no significant difference between the route of bleomycin administration (ORR, 69.2 vs. 81.9% following intravenous or intratumoral bleomycin, p = .37) and tumor size (p = .69). When reported (n = 8 studies), 1- and 2-year LCR ranged from 54 to 89% and 72 to 74%, respectively, and 1-year OS (n = 3 studies) from 67 to 89%.

CONCLUSIONS

ECT with either intratumoral or intravenous bleomycin confers a high therapeutic response in cutaneous metastatic melanoma. Moderate evidence supports its low toxicity and durability of local control.HighlightsElectrochemotherapy (ECT) is associated with a 77% overall response rate (ORR).Intravenous and intratumoral bleomycin are equally effective.There are no relevant toxicity concerns.One-year local tumor control rate ranges from 54 to 89%.Current literature has significant variation in reporting.

Non-Operative Options for Loco-regional Melanoma

Malignant melanoma is the 5th most common cancer and stage IV melanoma accounts for approximately 4% of new melanoma diagnoses in the United States. The prognosis for regionally advanced disease is poor, but there have been numerous recent advances in the medical management of melanoma in-transit metastases. The goal of this paper is to review currently accepted treatment options for in-transit metastases and introduce emerging therapies. Therapies to be discussed include limb perfusion and infusion, immunotherapy, checkpoint inhibitors, and radiation therapy.

Molecular Aspects of the Isolated Limb Infusion Procedure

For decades, isolated limb infusion (ILI) and hyperthermic isolated limb perfusion (HILP) have been used to treat melanoma in-transit metastases and unresectable sarcoma confined to the limb utilizing the effect of loco-regional high-dose chemotherapy to the isolated limb. Both procedures are able to provide high response rates in patients with numerous or bulky lesions in whom other loco-regional treatments are becoming ineffective. In comparison to systemic therapies, on the other hand, ILI and HILP have the advantage of not being associated with systemic side-effects. Although in principle ILI and HILP are similar procedures, ILI is technically simpler to perform and differs from HILP in that it takes advantage of the hypoxic and acidotic environment that develops in the isolated limb, potentiating anti-tumour activity of the cytotoxic agents melphalan +/− actinomycin-D. Due to its simplicity, ILI can be used in both preclinical and clinical studies to test new cytotoxic regimens and combinations with the aim to overcome tumour resistance. In the future, administration of cytotoxic agents by ILI, in combination with systemic treatments such as BRAF/MEK/KIT inhibitors, immunotherapy (CTLA-4 blockade), and/or programmed death (PD-1) pathway inhibitors, has the potential to improve responses further by inducing increased tumour cell death while limiting the ability of the tumour to suppress the immune response.

Factors predicting toxicity and response following isolated limb infusion for melanoma: An international multi-centre study

INTRODUCTION

Isolated limb infusion (ILI) is a minimally-invasive procedure for delivering high-dose regional chemotherapy to treat melanoma in-transit metastases confined to a limb. The aim of this international multi-centre study was to identify predictive factors for toxicity and response.

METHODS

Data of 687 patients who underwent a first ILI for melanoma in-transit metastases confined to the limb between 1992 and 2018 were collected at five Australian and four US tertiary referral centres.

RESULTS

After ILI, predictive factors for increased limb toxicity (Wieberdink grade III/IV limb toxicity, n = 192, 27.9%) were: female gender, younger age, procedures performed before 2005, lower limb procedures, higher melphalan dose, longer drug circulation and ischemia times, and increased tissue hypoxia. No patient experienced grade V toxicity (necessitating amputation). A complete response (n = 199, 28.9%) was associated with a lower stage of disease, lower burden of disease (BOD) and thinner Breslow thickness of the primary melanoma. Additionally, an overall response (combined complete and partial response, n = 441, 64.1%) was associated with female gender, Australian centres, procedures performed before 2005, lower limb procedures and lower actinomycin-D doses. On multivariate analysis, higher melphalan dose remained a predictive factor for toxicity, while lower stage of disease and lower BOD remained predictive factors for overall response.

CONCLUSION

ILI is safe and effective to treat melanoma in-transit metastases. Predictive factors for toxicity and response identified in this study will allow improved patient selection and optimization of intra-operative parameters to increase response rates, while keeping toxicity low.

First Eastern European experience of isolated limb infusion for in-transit metastatic melanoma confined to the limb: Is it still an effective treatment option in the modern era?

BACKGROUND

Isolated limb infusion (ILI) with cytotoxic agents is a simple and effective treatment option for patients with melanoma in-transit metastases (ITMs) confined to an extremity. Data for ILIs performed in Europe are sparse and to date no Eastern European ILI experience has been reported. The aim of the current study was to evaluate the efficacy of ILI in Estonia.

PATIENTS AND METHODS

Data for twenty-one patients were collected and analysed. All patients had melanoma ITMs and underwent an ILI between January 2012 and May 2018. The cytotoxic drug combination of melphalan and actinomycin-D was used. Drug circulation times were 20-30 min under mildly hyperthermic conditions (38-39 °C). Primary outcome measures were treatment response and overall survival.

RESULTS

Nineteen lower limb and two upper limb ILIs were performed. The female to male ratio was 18:3. The overall response rate (complete + partial response) was 76% (n = 16), with a complete response in 38% (n = 8). The overall long-term limb salvage rate was 90% (n = 19). During follow-up, eight patients (38%) died, two due to metastatic melanoma. Five-year overall survival was 57%.

CONCLUSION

This first Eastern European report of ILI for melanoma ITMs shows results comparable to those from other parts of the world. In this era of effective targeted and immune therapies, ILI remains a useful treatment option, with a high overall response rate and durable responses in patients with melanoma ITMs confined to a limb.

Treatment of Clinically Positive Cervical Lymph Nodes by Limited Local Node Excision and Adjuvant Radiotherapy in Melanoma Patients with Major Comorbidities

INTRODUCTION

When cervical lymph nodes are clinically positive for metastatic melanoma, surgeons may be hesitant to recommend a therapeutic complete lymph node dissection if the patient is elderly or has major comorbidities. A limited local node excision of the clinically positive nodes only, followed by adjuvant radiotherapy to the entire node field, may be an effective alternative in such patients.

METHODS

All patients who had presented with a primary head and neck melanoma or an unknown primary site and had subsequently undergone limited local node excision and adjuvant radiotherapy for macroscopically involved cervical nodes between 1993 and 2010 at a tertiary referral center were selected for study.

RESULTS

Twenty-eight patients were identified, with a median age of 78 years and a median of 2 major comorbidities. The 5-year regional control, disease-free survival, and overall survival rates were 69%, 44%, and 50%, respectively. At the time of data analysis, seven patients were alive without evidence of disease. Twenty-one patients had died: 11 of melanoma (4 with neck recurrence) and 10 of other causes (2 with neck recurrence).

CONCLUSIONS

Excision of clinically positive metastatic cervical lymph nodes followed by radiotherapy provides satisfactory regional disease control without risking serious morbidity or mortality in melanoma patients whose general condition is considered a contraindication for therapeutic complete lymph node dissection.

Safety and Efficacy of Isolated Limb Infusion Chemotherapy for Advanced Locoregional Melanoma in Elderly Patients: An Australian Multicenter Study

BACKGROUND

Isolated limb infusion (ILI) offers a minimally invasive treatment option for locally advanced extremity melanoma.

OBJECTIVE

The aim of the current study was to evaluate the safety and efficacy of ILI in elderly patients in an Australian multicenter setting.

METHODS

The results of 316 first ILI procedures, performed between 1992 and 2008 in five Australian institutions, were identified and analyzed, with the main focus on elderly patients (≥75 years of age). All institutions used the same protocol: melphalan was circulated in the isolated limb for 20-30 min (±actinomycin D), and toxicity, responses, and survival were recorded.

RESULTS

Characteristics of patients aged ≥75 years (n = 148) were similar to those aged <75 years (n = 168), except that older patients had more melanoma deposits (median 4 vs. 5; p = 0.035) and lower limb volumes (5.4 vs. 6.5 L; p = 0.001). Median drug circulation times were lower in the older group (21 vs. 24 min; p = 0.04), and older patients experienced less limb toxicity (grade III/IV in 22 and 37% of patients, respectively; p = 0.003). A complete response (CR) was seen in 27% of patients aged ≥75 years and in 38% of patients aged <75 years (p = 0.06), while overall response rates were 72 and 77%, respectively (p = 0.30). No difference in survival was seen (p = 0.69).

CONCLUSIONS

The ILI technique proved safe and effective in elderly patients. When present, toxicity was localized, and lower compared with younger patients, possibly due to shorter drug circulation times. CR rates were higher in younger patients, although not significantly, while overall response and survival were equal. Optimization of perioperative factors in elderly patients may allow response rates to be raised further, while maintaining low toxicity.