ABSTRACTBackground

Treatment strategies for advanced cutaneous melanoma (CM) patients, resistant or not treatable with novel target and immunotherapeutic drugs, remain a significant challenge, particularly for patients with unresectable stage IIIC/D disease localized to inferior limbs and pelvis, for whom specific outcomes are rarely considered.

Materials and methods

This is a prospective study of multidisciplinary treatments, including locoregional melphalan chemotherapy, in 62 BRAF wild-type CM patients with locoregional metastases in the inferior limbs and pelvis, including inguinal regions. Patients were either in progression following or ineligible for, or not treatable with novel immunotherapy. For exclusively inferior limb-localised disease, patients received locoregional melphalan chemotherapy performed by hyperthermic isolated limb perfusion (n = 19) or isolated limb infusion (n = 19), and for synchronous lesions localised to inferior limbs and pelvis, received hypoxic pelvic and limb perfusion (n = 24). Additional multidisciplinary therapy included local, locoregional and systemic treatments and the primary endpoint was tumour response.

Results

The objective response rate following first cycle of locoregional chemotherapy was 37.1% at 3 mo and median progression-free survival was 4-mo, with 12.9% procedure-related complications, 30.6% low-grade haematological toxicity and 11.3% severe limb toxic tissue reactions. Multivariate logistic regression showed that the odds of response were significantly higher for patients ≤ 75 y of age and for patients with locoregional metastases exclusively located in the inferior limbs.

Conclusion

In this subgroup of CM patients with BRAF wild-type status, locoregional metastases localized to inferior limbs and pelvis, in progression following or ineligible for immunotherapy, melphalan locoregional chemotherapy demonstrated a safe and effective profile.

Trial Registration

ClinicalTrials.gov Identifier NCT01920516; date of trial registration: August 6, 2013.

1. IntroductionCutaneous melanomas (CMs) are increasing in incidence and recur in approximately 10% of cases as locoregional metastases, including local recurrences, in-transit and satellites metastases, and regional lymph node metastases. Approximately 4% of locoregional metastases cumulatively localise to inferior limb, inguinal and pelvic regions, with synchronous inferior limb, inguinal region and/or pelvic involvement observed in approximately 2% of cases.1Wright FC Kellett S Look Hong NJ et al.Locoregional management of in-transit metastasis in melanoma: an Ontario Health (Cancer Care Ontario) clinical practice guideline., 2Trout AT Rabinowitz RS Platt JF Elsayes KM. Melanoma metastases in the abdomen and pelvis: frequency and patterns of spread., 3Guadagni S Fiorentini G Clementi M et al.Melphalan hypoxic perfusion with hemofiltration for melanoma locoregional metastases in the pelvis.Over the past 15 y, local, regional and systemic treatments for locoregional metastatic melanoma have evolved and high-volume specialist centres now provide local, regional, and systemic therapeutic options. However, these therapeutic options are not uniformly recommended by current international guidelines1Wright FC Kellett S Look Hong NJ et al.Locoregional management of in-transit metastasis in melanoma: an Ontario Health (Cancer Care Ontario) clinical practice guideline.,4Coit DG Thompson JA Albertini MR et al.Cutaneous melanoma, Version 2.2019., 5Perone JA Farrow N Tyler DS Beasley GM. Contemporary approaches to in-transit melanoma., 6Michielin O van Akkooi A Lorigan P et al.ESMO consensus conference recommendations on the management of locoregional melanoma: under the auspices of the ESMO Guidelines Committee., 7Garbe C Amaral T Peris K et al.On behalf of the European Dermatology Forum (EDF), the European Association of Dermato-Oncology (EADO), and the European Organization for Research and Treatment of Cancer (EORTC). European consensus-based interdisciplinary guideline for melanoma. Part 2: treatment - update 2019., , 9National Health Commission of the People's Republic of China
Chinese guidelines for diagnosis and treatment of melanoma 2018., 10Nakamura Y Asai J Igaki H et al.Japanese Dermatological Association Guidelines: outlines of guidelines for cutaneous melanoma 2019.; in particular, there are guideline differences in recommended local therapeutic procedures and both Japanese10Nakamura Y Asai J Igaki H et al.Japanese Dermatological Association Guidelines: outlines of guidelines for cutaneous melanoma 2019. and some European guidelines7Garbe C Amaral T Peris K et al.On behalf of the European Dermatology Forum (EDF), the European Association of Dermato-Oncology (EADO), and the European Organization for Research and Treatment of Cancer (EORTC). European consensus-based interdisciplinary guideline for melanoma. Part 2: treatment - update 2019. do not recommend locoregional chemotherapy. Local treatments include surgical resection, electro-chemotherapy (ECT), ablative, topical and intralesional therapies.11Managing in-transit melanoma metastases in the new era of effective systemic therapies for melanoma., 12Lardone RD Chan AA Lee AF et al.Mycobacterium bovis Bacillus Calmette–Guérin alters melanoma microenvironment favoring antitumor T cell responses and improving M2 macrophage function., 13Caracò C Marone U Simeone E et al.Electrochemotherapy in melanoma patients: a single institution experience. Regional treatment options include regional radiation therapy14Role of radiation therapy in cutaneous melanoma. and locoregional chemotherapy by hyperthermic isolated limb perfusion (HILP) or isolated limb infusion (ILI) for locoregional melanoma metastases located in the limbs,1Wright FC Kellett S Look Hong NJ et al.Locoregional management of in-transit metastasis in melanoma: an Ontario Health (Cancer Care Ontario) clinical practice guideline. or hypoxic pelvic and limb perfusion (HPLP) for cases of synchronous inferior limb and inguinal region and/or pelvic involvement.15Guadagni S Santinami M Patuzzo R et al.Hypoxic pelvic and limb perfusion with melphalan and mitomycin C for recurrent limb melanoma: a pilot study. Systemic treatments, currently proposed for locoregional metastases judged to be unresectable for technical or clinical reasons, include single or combinations of agents with local and/or regional treatments.11Managing in-transit melanoma metastases in the new era of effective systemic therapies for melanoma. In patients with unresectable stage III and IV CM, 4-y overall survival (OS) rate of approximately 58% and median survival time of approximately 20 mo have been reported.16Tie EN Lai-Kwon JE Gyorki DE. Systemic therapies for unresectable locoregional melanoma: a significant area of need. Patients with unresectable stage III melanoma, however, represent only 3% of cases evaluated in novel target and immunotherapy studies over the past 5 y, making it impossible to extrapolate accurate outcomes of stage IIIC/D patients with synchronous locoregional metastases in inferior limbs and pelvis.16Tie EN Lai-Kwon JE Gyorki DE. Systemic therapies for unresectable locoregional melanoma: a significant area of need. Furthermore, target therapy has been reported to provide a significant improvement in overall median survival of only 50% in patients with BRAFV600E mutated CM,17Are we there yet? Prolonged MAPK inhibition in BRAF V600-mutant melanoma.,18Chan MM Haydu LE Menzies AM et al.The nature and management of metastatic melanoma after progression on BRAF inhibitors: Effects of extended BRAF inhibition. and novel immunotherapies reported to be efficacious in only approximately 45% of patients with wild-type BRAF CM.19Topollian SL Sznol M McDermott DF et al.Survival, durable tumor remission, and long-term safety in patients with advanced melanoma receiving nivolumab., 20Ribas A Hamid O Daud A et al.Association of pembrolizumab with tumor response and survival among patients with advanced melanoma., 21Pembrolizumab for melanoma-safety profile and future trends. Moreover, patients presenting with concomitant autoimmune disorders, chronic viral infections, organ dysfunction, organ transplants, brain metastases or who are either pregnant, too old or too frail have been excluded from the majority of immune checkpoint inhibitor clinical trials, although a number of trials have addressed systemic therapies in patients with brain metastases and trials are ongoing in patients with organ transplants.22Johnson DB Sullivan RJ Menzies AM. Immune checkpoint inhibitors in challenging populations.The current plethora of therapeutic options for melanoma not only reflects the fact that not all treatments are available in every institution but also that no single therapeutic strategy fits all cases. The selection of therapy is based on lesion number, size and anatomic location, regional lymph node involvement and/or distant metastases, biomolecular aspects, concomitant disease and response to previous therapies.11Managing in-transit melanoma metastases in the new era of effective systemic therapies for melanoma. According to the majority of current guidelines,1Wright FC Kellett S Look Hong NJ et al.Locoregional management of in-transit metastasis in melanoma: an Ontario Health (Cancer Care Ontario) clinical practice guideline. therefore, a multidisciplinary therapeutic approach to CM should include locoregional chemotherapy, particularly for patients with locoregional inferior limb and pelvic metastases not responsive or eligible for novel target and immune therapies, who traditionally have bad therapeutic outcomes.23Guadagni S Fiorentini G Clementi M et al.Does locoregional chemotherapy still matter in the treatment of advanced pelvic melanoma?.,24Guadagni S Fiorentini G Clementi M et al.MGMT methylation correlates with melphalan pelvic perfusion survival in stage III melanoma patients: a pilot study.

Here, we address this issue in a prospective, real-life, open-label, multicentre study of a selected group of stage IIIC and IIID wild-type BRAF CM patients with locoregional inferior limb, pelvic and/or inguinal metastases, in progression following or not eligible for novel immune therapies. This patient population was submitted for multidisciplinary treatments, including locoregional melphalan chemotherapy.

4. DiscussionImprovement in the treatment of CM patients with locoregional metastases in inferior limbs and in pelvic or inguinal regions, is an important objective of translational and clinical research, and is of particular relevance to wild-type BRAF CM patients, in progression following or ineligible for novel immunotherapy. The most relevant aspect of this study is that it considers a subgroup of stage IIIC/D CM patients that, over the past 5 y, has only represented approximately 3% of reported cases in clinical trials of novel therapy drugs.16Tie EN Lai-Kwon JE Gyorki DE. Systemic therapies for unresectable locoregional melanoma: a significant area of need. This subgroup is characterized by frequent bad outcomes when not treatable or not responsive to novel target and immunotherapeutic agents17Are we there yet? Prolonged MAPK inhibition in BRAF V600-mutant melanoma., 18Chan MM Haydu LE Menzies AM et al.The nature and management of metastatic melanoma after progression on BRAF inhibitors: Effects of extended BRAF inhibition., 19Topollian SL Sznol M McDermott DF et al.Survival, durable tumor remission, and long-term safety in patients with advanced melanoma receiving nivolumab., 20Ribas A Hamid O Daud A et al.Association of pembrolizumab with tumor response and survival among patients with advanced melanoma., 21Pembrolizumab for melanoma-safety profile and future trends. and clearly requires a better therapeutic strategy, including those evaluated in the present report.For this specific subgroup of advanced CM patients, our study supports the international guidelines recommending a multidisciplinary treatment including locoregional chemotherapy, by demonstrating a 37.1% ORR following the first cycle of locoregional chemotherapy, associated with 12.9% procedure-related complications, 30.6% low-grade haematological toxicity and 11.3% severe limb toxic tissue reactions. Furthermore, multivariate logistic regression revealed that responses were significantly higher in patients of ≤ 75 y of age and in patients with locoregional metastases located exclusively to inferior limbs. An additional important message from this study, is that patients eligible for maximally aggressive regional therapies had higher responses and enjoyed long-term benefits. Moreover, locoregional chemotherapy followed by multidisciplinary treatments elicited a median OS time of 20 mo (IQR = 14-30 mo), which is similar to the reported OS time for BRAF-mutated CM patients treated with novel target or immunotherapeutic agents,16Tie EN Lai-Kwon JE Gyorki DE. Systemic therapies for unresectable locoregional melanoma: a significant area of need. though, a direct comparison cannot accurately be made considering the high number of stage IV CM patients included in systemic therapeutic studies.The choice of locoregional chemotherapeutic procedure depends initially upon the localisation of locoregional metastases. For metastatic disease localised to inferior limbs, pelvic and inguinal regions, HPLP is the only procedure that can deliver drugs to all metastases within the perfused compartment, considering that HILP and ILI only partially reach inguinal lesions and cannot deliver drugs to deep pelvic lesions.34Guadagni S Russo F Rossi CR et al.Deliberate hypoxic pelvic and limb chemoperfusion in the treatment of recurrent melanoma. In contrast, either HILP or ILI are appropriate procedures for metastatic lesions localised exclusively to inferior limbs. An important message arising from this study is that in this stage IIIC/D WT-BRAF CM cohort, consisting of patients with synchronous limb and pelvic locoregional metastases in progression after or ineligible for novel target and immunotherapy, HPLP elicited a 12.5% ORR following the first cycle of locoregional chemotherapy and a median OS time of 18.5 mo (IQR = 10-21.5), if followed by other multidisciplinary treatments. For this particular subset, the clinical benefits of systemic chemotherapy, interferon or interleukin-based immunotherapy are unsatisfactory, and remain to be defined for other therapies, such as local injectables, ECT or RT.11Managing in-transit melanoma metastases in the new era of effective systemic therapies for melanoma. With respect to the choice between HILP and ILI, although phase III prospective randomized trials comparing these two procedures have not yet been initiated, there is general consensus that HILP is more effective than ILI but is more complex and associates with more adverse events.1Wright FC Kellett S Look Hong NJ et al.Locoregional management of in-transit metastasis in melanoma: an Ontario Health (Cancer Care Ontario) clinical practice guideline. It is for these reasons that our multidisciplinary board recommended the HILP procedure for the treatment of locoregional limb metastases in patients 75 y old and/or ECOG performance status ≥ 2. This procedure selection bias was considered and weighted in both the logistic regression model used to evaluate the effect of patient/tumour variables on response and the multivariate Cox regression model used to evaluate PFS and OS. In our study, the 98.5% ORR and 39 mo median OS time associated to HILP, confirm the literature,1Wright FC Kellett S Look Hong NJ et al.Locoregional management of in-transit metastasis in melanoma: an Ontario Health (Cancer Care Ontario) clinical practice guideline. whereas the 15.8% ORR elicited by ILI is considerably lower than that (64.1%) reported in a previous multicentre study.35Miura JT Kroon HM Beasley GM et al.Long-term oncologic outcomes after isolated limb infusion for locoregionally metastatic melanoma: an international multicenter analysis. This difference may relate to the fact that patients in our study were significantly older (78 y, IQR = 70-84) than those in the latter study,35Miura JT Kroon HM Beasley GM et al.Long-term oncologic outcomes after isolated limb infusion for locoregionally metastatic melanoma: an international multicenter analysis. exhibited a worse ECOG performance status, did not include stage IIIB disease, had been unsuccessfully pre-treated for locoregional metastases in 42% of cases, and were submitted for a different therapeutic regimen. Therefore, ILI should not be refused for frail >75-y-old CM patients, if one considers that HILP is too aggressive, the only parameter assessed during best supportive care is symptom improvement and the clinical benefit of alternative local therapies remains to be elucidated.11Managing in-transit melanoma metastases in the new era of effective systemic therapies for melanoma.

In this non randomized study, OS was pre-defined as a secondary endpoint. This decision was based upon the relatively small number of patients enrolled, the high number of patients with stage IIID disease, the high percentage (61.3%) of patients previously treated for locoregional metastases, the high percentage of patients (30.6%) considered ineligible for novel immunotherapeutic drugs, and the heterogeneity of multidisciplinary treatments. Multivariate survival analysis, performed considering the criteria adopted for the choice of locoregional chemotherapy procedure and collinearity of variables, highlighted an increased risk of death in patients with stage IIID disease.

With regard to future perspectives, the 20-mo median OS time observed in the subgroup evaluated in this study could be improved by enhancing the efficacy of locoregional chemotherapy and by combining locoregional chemotherapy with other local, regional or systemic therapies. In this respect, although melphalan was the only therapeutic agent used in our study for reasons of sample homogeneity, several studies have reported interesting results for melphalan combined with other drugs.36Nooijen PT Manusama ER Eggermont AM et al.Synergistic effects of TNF-alpha and melphalan in an isolated limb perfusion model of rat sarcoma: A histopathological, immunohistochemical and electron microscopical study., 37

Beasley GM, Miura J, Zager JS, Tyler DS, Thompson JF, Kroon HM. Isolated limb infusion for melanoma. In: Balch CM, Thompson JF, Gershenwald JE, Atkins MB, Kirkwood JM, McArthur G, et al., editors. Cutaneous Melanoma. 6th edition. Switzerland: Springer Nature AG; 2020; pp. 827-50.

, 38Beasley GM Riboh JC Augustine CK et al.Prospective multicenter phase II trial of systemic ADH-1 in combination with melphalan via isolated limb infusion in patients with advanced extremity melanoma., 39Vo KT Matthay KK DuBois SG. Targeted antiangiogenic agents in combination with cytotoxic chemotherapy in preclinical and clinical studies in sarcoma., 40Padussis JC Steerman SN Tyler DS Mosca PJ. Pharmacokinetics & drug resistance of melphalan in regional chemotherapy: ILP versus ILI. Moreover, the use of fresh tissues biopsies, liquid biopsies and purified circulating tumour cells in chemosensitivity and tumour gene expression assays can be used to develop more personalized locoregional or systemic treatment strategies, as recently reported.41Guadagni S Fiorentini G Papasotiriou I et al.Circulating tumour cell liquid biopsy in selecting therapy for recurrent cutaneous melanoma with locoregional pelvic metastases: a pilot study. With respect to locoregional chemotherapy and other therapy combinations, the use of ablative techniques, ECT, topical and intralesional therapy is under current investigation7Garbe C Amaral T Peris K et al.On behalf of the European Dermatology Forum (EDF), the European Association of Dermato-Oncology (EADO), and the European Organization for Research and Treatment of Cancer (EORTC). European consensus-based interdisciplinary guideline for melanoma. Part 2: treatment - update 2019.,11Managing in-transit melanoma metastases in the new era of effective systemic therapies for melanoma., 12Lardone RD Chan AA Lee AF et al.Mycobacterium bovis Bacillus Calmette–Guérin alters melanoma microenvironment favoring antitumor T cell responses and improving M2 macrophage function., 13Caracò C Marone U Simeone E et al.Electrochemotherapy in melanoma patients: a single institution experience., 14Role of radiation therapy in cutaneous melanoma. and novel immunotherapies are increasing due to a broadening of eligibility criteria, with several clinical trials now including patients previously considered ineligible.22Johnson DB Sullivan RJ Menzies AM. Immune checkpoint inhibitors in challenging populations. Furthermore, it has been reported that ILI with melphalan followed by systemic administration of ipilimumab provided an 85% ORR associated to increased T-cell infiltration in locoregional metastases of 26 melanoma patients, suggesting that locoregional chemotherapy administered as immune stimulant therapy could potentiate immune-responses.42Ariyan CE Brady MS Siegelbaum RH et al.Robust antitumor responses result from local chemotherapy and CTLA-4 blockade. Finally, novel agnostic therapeutic agents, such as larotrectinib and entrectinib, that inhibit mutation and deletion-activated Trk oncogenes, elicit remarkable durable responses in a wide range of advanced stage Trk-fusion oncogene-driven cancers, including melanoma.43Cappabianca L Guadagni S Maccarone R et al.A pilot study of alternative TrkAIII splicing in Merkel cell carcinoma: A potential oncogenic mechanism and novel therapeutic target.Author contributions

Study concept and design (SG, OZ, GF); acquisition of data (KL, MC, DS); analysis and interpretation of data (FM, SG, OZ, GF, KL, MC, DS); drafting of the manuscript (SG, ARM, KL, DS); critical revision of the manuscript for important intellectual content (ARF, DS, KL, GF, SG).