Response durability after cessation of immune checkpoint inhibitors in patients with metastatic Merkel cell carcinoma: a retrospective multicenter DeCOG study.

BACKGROUND: Immune checkpoint inhibitors (ICI) have led to a prolongation of progression-free and overall survival in patients with metastatic Merkel cell carcinoma (MCC). However, immune-mediated adverse events due to ICI therapy are common and often lead to treatment discontinuation. The response duration after cessation of ICI treatment is unknown. Hence, this study aimed to investigate the time to relapse after discontinuation of ICI in MCC patients. METHODS: We analyzed 20 patients with metastatic MCC who have been retrospectively enrolled at eleven skin cancer centers in Germany. These patients have received ICI therapy and showed as best overall response (BOR) at least a stable disease (SD) upon ICI therapy. All patients have discontinued ICI therapy for other reasons than disease progression. Data on treatment duration, tumor response, treatment cessation, response durability, and tumor relapse were recorded. RESULTS: Overall, 12 of 20 patients (60%) with MCC relapsed after discontinuation of ICI. The median response durability was 10.0 months. Complete response (CR) as BOR to ICI-treatment was observed in six patients, partial response (PR) in eleven, and SD in three patients. Disease progression was less frequent in patients with CR (2/6 patients relapsed) as compared to patients with PR (7/11) and SD (3/3), albeit the effect of initial BOR on the response durability was below statistical significance. The median duration of ICI therapy was 10.0 months. Our results did not show a correlation between treatment duration and the risk of relapse after treatment withdrawal. Major reasons for discontinuation of ICI therapy were CR (20%), adverse events (35%), fatigue (20%), or patient decision (25%). Discontinuation of ICI due to adverse events resulted in progressive disease (PD) in 71% of patients regardless of the initial response. A re-induction of ICI was initiated in 8 patients upon tumor progression. We observed a renewed tumor response in 4 of these 8 patients. Notably, all 4 patients showed an initial BOR of at least PR. CONCLUSION: Our results from this contemporary cohort of patients with metastatic MCC indicate that MCC patients are at higher risk of relapse after discontinuation of ICI as compared to melanoma patients. Notably, the risk of disease progression after discontinuation of ICI treatment is lower in patients with initial CR (33%) as compared to patients with initial PR (66%) or SD (100%). Upon tumor progression, re-induction of ICI is a feasible option. Our data suggest that the BOR to initial ICI therapy might be a potential predictive clinical marker for a successful re-induction.

[Cutaneous angiosarcoma : Radiochemotherapy with liposomal pegylated doxorubicin]. / Kutanes Angiosarkom : Radiochemotherapie mit liposomal verkapseltem pegyliertem Doxorubicin.

BACKGROUND: Whilst cutaneous angiosarcoma is rare tumour which primarily affects elderly patients, its management presents a significant therapeutic challenge. Indeed, complete surgical excision is often not possible due to the location and the diffuse and extensive nature of the tumour. Therefore, current treatment strategies often include chemo- and/or radiotherapy. METHODS: We report our experience of combined chemo- and radiotherapy in the clinical course of 6 patients with cutaneous angiosarcoma who were treated between 2007 and 2018. RESULTS: All patients presented non-resectable tumours and were treated with radiotherapy in combination with the administration of liposomal, pegylated doxrubicin (25 mg/m2 every 2 weeks). The mean duration of progression-free survival was 8 months (5-14 months), corresponding to an overall survival of 13 months (13-34 months). A partial response was seen in 4 patients and 1 patient developed progressive disease. One patient abandoned therapy after one administration. Two patients developed severe adverse events which led to termination of therapy after 1.5 months and 7 months, i.e. after 4 and 15 cycles respectively. DISCUSSION: Combined radio- and chemotherapy with liposomal, pegylated doxorubicin is a useful therapeutic option in the management of cutaneous angiosarcoma. Given the short-lived response rate, new treatment options are urgently required.

[Immune checkpoint inhibition in Merkel cell carcinoma]. / Immuncheckpointinhibition beim Merkel-Zell-Karzinom.

BACKGROUND: Merkel cell carcinoma (MCC) is a rare but aggressive form of skin cancer in which Merkel cell polyomavirus infection and chronic exposure to ultraviolet radiation are key risk factors. Immune checkpoint inhibition has revolutionized the treatment of locally advanced, inoperable and metastatic MCC. AIM: To outline the modern management of MCC based on advances in our understanding of MCC tumour biology and the development of immune checkpoint inhibitors, namely inhibitors of programmed cell death protein (PD)-1- and PD­1 ligand 1 (PD-L1). METHODS: A review of the scientific literature listed in PubMed. RESULTS: First line therapy with the PD-L1 blocking antibody avelumab is associated with a response rate of 62%. In the second line setting, for example after chemotherapy, the response rate only reaches 33%. However, in patients who responded in the second line setting, 69% remained relapse free after 2 years. Treatment responses occurred on average after 6.1 weeks of therapy. First line treatment with pembrolizumab (anti-PD­1 antibody) is associated with a 2-year survival rate of 69% and the median survival rate has not been reached. Whilst the various chemotherapy regimens are associated with similar response rates, these are typically short lived. DISCUSSION: Checkpoint inhibition offers an effective treatment option for patients with MCC. Avelumab is currently licensed as a treatment for metastatic disease. Chemotherapy remains an option to reduce tumor load, or in the context of resistance and/or contraindications to immune checkpoint therapy. Adjuvant and neoadjuvant use of checkpoint inhibition in MCC may represent a future treatment strategy pending the results of on-going clinical trials.

[Response of BRAF(L597Q)-mutant melanoma to trametinib : Targeted melanoma therapy beyond BRAF(V600) mutations]. / Ansprechen eines BRAF(L597Q)-mutierten Melanoms auf Trametinib : Zielgerichtete Melanomtherapie jenseits der BRAF(V600)-Mutationen.

Approximately 7 % of melanomas have a BRAF mutation beyond codon 600. These mutations can be BRAF activating without being addressable by an approved BRAF inhibitor. The case of a patient with fulminant metastatic melanoma and a BRAF(L597Q) mutation is presented. It is demonstrated that the tumor shows an excellent response to the MEK inhibitor trametinib. This is an example for possible targeted therapy in a non-V600-mutated melanoma resulting in a 17-month overall survival.

[Complex cutaneous leishmaniasis with bone involvement]. / Komplexe kutane Leishmaniose mit ossärer Beteiligung.

We report an immunocompromised patient with a complex cutaneous leishmaniasis (CL) who suffered from singular bone involvement of the little left toe due to Leishmania (L.) infantum infection. The diagnosis was confirmed by positive polymerase chain reaction (PCR) testing in skin and bone tissue. The patient was successfully treated with miltefosine. In immunocompromised patients with CL, extracutaneous manifestations should always be ruled out. This is the first case report describing osseous involvement in CL due to Leishmania infantum.

Early switch from run-in treatment with vemurafenib plus cobimetinib to atezolizumab after 3 months leads to rapid loss of tumour control in patients with advanced BRAFV600-positive melanoma: The ImmunoCobiVem phase 2 randomised trial.

AIM: ImmunoCobiVem investigated whether a planned switch to atezolizumab after achieving tumour control during run-in with vemurafenib + cobimetinib improves progression-free survival (PFS) and overall survival (OS) compared to continuous targeted therapy (TT) in patients with previously untreated advanced BRAFV600-mutated melanoma. METHODS: In this multicenter phase 2 study, patients received vemurafenib plus cobimetinib. After 3months, patients without progressive disease (PD) were randomly assigned (1:1) to continue vemurafenib + cobimetinib (Arm A) or switch to atezolizumab (Arm B) until first documented PD (PD1). Primary outcome was PFS1 (time from start of run-in until PD1 or death). OS and safety were also assessed. RESULTS: Of 185 patients enroled between November 2016 and December 2019, 135 were randomly assigned after the run-in period (Arm A, n = 69; Arm B, n = 66). Median PFS1 was significantly longer in Arm A versus Arm B (13.9 versus 5.9months; hazard ratio [HR] 0.55; 95% confidence interval [CI], 0.37-0.84; PStratified=0.001). Median OS was not reached in either arm (HR 1.22; 95%CI, 0.69-2.16; PStratified=0.389); 2-year OS was higher in Arm B versus Arm A (67%; 95%CI, 53-78 versus 58%; 95%CI, 45-70). Grade 3/4 AEs occurred in 55% of patients in Arm A and 64% in Arm B; treatment-related AEs led to discontinuation of any drug in 7% and 9% of patients, respectively. CONCLUSION: In patients with BRAFV600-mutated advanced melanoma who achieve tumour control with TT, early switch at 3months to atezolizumab led to rapid loss of tumour control but provided a numerical OS benefit at 2years compared with continued TT.

Avelumab in patients with previously treated metastatic Merkel cell carcinoma (JAVELIN Merkel 200): updated overall survival data after >5 years of follow-up.

BACKGROUND: Merkel cell carcinoma (MCC) is a rare, aggressive skin cancer that has a poor prognosis in patients with advanced disease. Avelumab [anti-programmed death-ligand 1 (PD-L1)] became the first approved treatment for patients with metastatic MCC (mMCC), based on efficacy and safety data observed in the JAVELIN Merkel 200 trial. We report long-term overall survival (OS) data after >5 years of follow-up from the cohort of patients with mMCC whose disease had progressed after one or more prior lines of chemotherapy. PATIENTS AND METHODS: In Part A of the single-arm, open-label, phase II JAVELIN Merkel 200 trial, patients with mMCC that had progressed following one or more prior lines of chemotherapy received avelumab 10 mg/kg by intravenous infusion every 2 weeks until confirmed disease progression, unacceptable toxicity, or withdrawal. In this analysis, long-term OS was analyzed. RESULTS: In total, 88 patients were treated with avelumab. At data cut-off (25 September 2020), median follow-up was 65.1 months (range 60.8-74.1 months). One patient (1.1%) remained on treatment, and an additional patient (1.1%) had reinitiated avelumab after previously discontinuing treatment. Median OS was 12.6 months [95% confidence interval (CI) 7.5-17.1 months], with a 5-year OS rate of 26% (95% CI 17% to 36%). In patients with PD-L1+ versus PD-L1- tumors, median OS was 12.9 months (95% CI 8.7-29.6 months) versus 7.3 months (95% CI 3.4-14.0 months), and the 5-year OS rate was 28% (95% CI 17% to 40%) versus 19% (95% CI 5% to 40%), respectively (HR 0.67; 95% CI 0.36-1.25). CONCLUSION: Avelumab monotherapy resulted in meaningful long-term OS in patients with mMCC whose disease had progressed following chemotherapy. These results further support the role of avelumab as a standard of care for patients with mMCC.

Sequence-dependent cross-resistance of combined radiotherapy plus BRAFV600E inhibition in melanoma.

INTRODUCTION: Treatment of patients with metastatic melanoma is hampered by drug-resistance and often requires combination with radiotherapy as last-resort option. However, also after radiotherapy, clinical relapses are common. METHODS & RESULTS: Our preclinical models indicated a higher rate of tumour relapse when melanoma cells were first treated with BRAFV600E inhibition (BRAFi) followed by radiotherapy as compared to the reverse sequence. Accordingly, retrospective follow-up data from 65 stage-IV melanoma patients with irradiated melanoma brain metastases confirmed a shortened duration of local response of mitogen-activated protein kinase (MAPK)-inhibitor-pretreated compared with MAPK-inhibitor-naïve intracranial metastases. On the molecular level, we identified JARID1B/KDM5B as a cellular marker for cross-resistance between BRAFi and radiotherapy. JARID1Bhigh cells appeared more frequently under upfront BRAFi as compared with upfront radiation. JARID1B favours cell survival by transcriptional regulation of genes controlling cell cycle, DNA repair and cell death. CONCLUSION: The level of cross-resistance between combined MAPK inhibition and radiotherapy is dependent on the treatment sequence. JARID1B may represent a novel therapy-overarching resistance marker.

Chemoimmunotherapy for cutaneous melanoma with dacarbazine and epifocal contact sensitizers: results of a nationwide survey of the German Dermatologic Co-operative Oncology Group.

PURPOSE: To scrutinize published data from small mono-centric studies and case reports which implicated high response rates and promising survival times for a combination therapy consisting of epifocal dinitrochlorobenzene (DNCB) and dacarbazine (DTIC) for metastasized melanoma. This therapy merges the effects of an allergic contact dermatitis elicited at the site of a cutaneous metastasis, and systemic chemotherapy. METHODS: We performed a retrospective survey with nine German centers and evaluated 72 patients treated from 1993 to 2005. RESULTS: The objective response rate in stage III melanoma (n = 39) was 62%. In contrast, only 9% objective responses were observed in 33 stage IV patients. Interestingly, more than half of patients with objective remissions remained progression-free for more than 1 year irrespective of the stage of disease. CONCLUSIONS: Epifocal DNCB combined with DTIC is effective in patients with regionally metastasized melanoma not amenable to surgery or isolated limb perfusion, whereas in stage IV disease in spite of few durable remissions the addition of DNCB does not improve the therapeutic efficacy of DTIC.

Oligoclonal T-cell receptor usage of melanocyte differentiation antigen-reactive T cells in stage IV melanoma patients.

Ex vivo ELISPOT analysis of peripheral blood lymphocytes obtained from stage IV melanoma patients demonstrated reactivity against peptides derived from MART-1 and gp100. However, the number of reactive T cells was < 1% that of total lymphocytes as detected by flow cytometry using tetrameric MHC/peptide complexes. Despite this low frequency, we were able to directly isolate these populations ex vivo by means of magnetic beads coated with MHC/peptide complexes and to subject these cells to T-cell receptor clonotype mapping. This analysis revealed that the MART-1/A*0201- and gp100/A*0201-reactive T-cell populations are composed of oligoclonal T cells that engage several T-cell receptor beta chain families. Longitudinal studies using this approach may result in a better correlation between T-cell reactivity and the course of neoplastic disease.

[Development of serous retinopathy during therapy of a metastatic cutaneous melanoma]. / Entwicklung einer serösen Retinopathie unter Behandlung eines metastasierten kutanen Melanoms.

Inhibitors of the mitogen-activated protein kinase (MAPK) signal pathway have decisively improved the prognosis of metastatic cutaneous melanoma in patients with an activating mutation in position V600 of the BRAF gene. We report on a patient who was regularly examined in our clinic while participating in a randomized blinded clinical trial. The aim of this trial was to examine the effectiveness and tolerability of a combination of the BRAF inhibitor dabrafenib and the MAPK kinase (MEK) inhibitor trametinib compared with a monotherapy with dabrafenib (plus placebo). During therapy the patient developed a diffuse neuroretinal detachment which could not be completely reversed after discontinuation of the study medication.

Expression of CD94/NKG2 subtypes on tumor-infiltrating lymphocytes in primary and metastatic melanoma.

Natural killer receptors are expressed both on natural killer populations and subpopulations of T cells, mainly alpha/beta TCR+CD8+ T cells. We have characterized the expression of the C-type lectin natural killer receptor CD94/NKG2 on tumor-infiltrating lymphocytes in primary and metastatic melanoma lesions. By immunohistochemistry, 5-10% of the tumor-infiltrating lymphocytes, both in primary and metastatic lesions, expressed CD94. More than 95% of these CD94+ cells coexpressed CD8 and the percentage of CD94 expression within the CD8+ cell population ranged from 5 to 20% with a higher expression in metastatic lesions. CD94/NKG2 exists both in an inhibitory and an activating form; thus, it was necessary to determine whether the inhibitory CD94/NKG2-A/B, the activating CD94/NKG2-C/E, or both were expressed on tumor-infiltrating lymphocytes. Reverse transcription-polymerase chain reaction using specific primers for NKG2-A/B and C/E mRNA revealed the presence of NKG2-C/E in all primary and metastatic lesions. In contrast, the inhibitory NKG2-A/B was only present in 50% of primary tumors whereas 80% of tumor-infiltrating lymphocytes in metastatic lesions expressed these transcripts. In healthy humans, the mean number of inhibitory natural killer receptors is higher than that of activating receptors, but the opposite was true for tumor-infiltrating lymphocytes in melanoma. The reversal of the ratio of inhibitory to activating natural killer receptors among tumor-infiltrating lymphocytes suggests a regulated event due to either specific factors within the tumor microenvironment, preferential homing of T cell subsets, or certain stages of T cell activation.

Predominant expression of Fas (CD95) ligand in metastatic melanoma revealed by longitudinal analysis.

The expression of Fas ligand has recently been proposed as a novel tumor escape mechanism for melanoma. To establish the characteristics of Fas ligand expression during the course of melanoma progression we performed a longitudinal study analyzing primary tumors as well as subsequently evolving metastases. In primary melanoma Fas ligand was expressed in two of 20 lesions; this expression was weak and restricted to few parts of the tumors. The Fas ligand positive primary melanomas were rather thick, i.e., 8.5 and 3.8 mm, versus a median of 2.4 mm of the remaining tumors. In contrast, for metastatic melanoma Fas ligand expression was present in six of 11 cases investigated. The metastases of primary tumors displaying Fas ligand maintained its expression. As Fas ligand positive melanoma cells are capable of inducing apoptosis in susceptible cells, e.g., Fas positive tumor infiltrating lymphocytes, we tested for the presence of apoptotic cells in situ by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. This analysis revealed that apoptotic cells were present within the Fas ligand positive tumors. The number of apoptotic cells, however, never exceeded 5% of the total cells. Thus, Fas ligand mediated apoptosis does not seem to be a major immune escape mechanism for melanoma but its expression correlates with the stage of melanoma.

Clinical evaluation of in vitro chemosensitivity testing: the example of uveal melanoma.

PURPOSE: Results from in vitro chemosensitivity testing recommend treosulfan/gemcitabine chemotherapy for the treatment of stage IV uveal melanoma. METHODS: Twenty patients received treosulfan 3,500 mg/m2 followed by gemcitabine 1,000 mg/m2 on day 1 and day 8 repeated on day 29. In cases of prior chemotherapy only 75% of these dosages were used. RESULTS: Without any patient achieving an objective response, 25% of patients (95% confidence interval, 8.6-49.1%) had stabilisation of disease. This stabilisation was associated with a prolonged median overall survival of 17 months compared with 7 months for the patients with progressive disease. First-line treatment was not associated with better response or survival although prognostic parameters did not significantly differ from that of other patients. CONCLUSIONS: The results are disappointing and question the value of individualized chemotherapy based on in vitro assays.

Molecular basis of T-cell dysfunction in melanoma.

Human melanoma is an immunogenic tumour which is characterized by a number of defined tumour-associated antigens and a specific T-cell-mediated immune response. Nevertheless, there is only limited evidence for an effective antitumour immune response able to eradicate established melanoma. Thus, the existence of an immunologically suppressed state in the tumour-bearing host has become an axiom in tumour immunology. There is increasing evidence that abnormalities in signal transduction events involved in cell activation are the molecular basis for the observed T-cell dysfunction. These abnormalities include altered patterns of protein tyrosin phosphorylation, decreased protein levels of the Src-family kinases p56(lck) and p59(lyn), and of the CD3zeta chain. Furthermore, differences in the expression of transcription factors of the nuclear factor NF-kappaB/Rel family have been described.

Sequential interferon-alpha2b, interleukin-2 and fotemustine for patients with metastatic melanoma.

The aim of this study was the evaluation of both the antitumour activity and toxicity of an immunochemotherapeutic regimen consisting of interferon-alpha2b and interleukin-2 in combination with fotemustine for patients with metastatic melanoma. To improve the penetration of fotemustine into the brain, it was given immediately after immunotherapy, when the blood-brain barrier is still disturbed. Of the 19 patients treated, three complete remissions (CRs) and one partial remission (PR) were induced, giving an objective response rate of 21% (95% confidence interval 6-46%). The durations of the CRs were 9, 19 and 44 months; the PR lasted for 59+ months. The overall survival times for the patients with CR were 21, 25 and 70+ months, and 59+ months for the PR. For nine patients (47%, 95% confidence interval 24-71%) disease was stabilized for a median period of 8 months (range 2-18 months), resulting in a median survival of 18 months (range 10-41+ months). No haematological toxicity of World Health Organization grade 3 or more was observed and in general toxicity was low. In summary, this immunochemotherapy regimen led to long-term survival in occasional patients, and about half of the patients achieved stable disease, with prolonged treatment- and progression-free survival compared with nonresponding patients. The occurrence of brain metastases, however, was not prevented, and in fact was the site of recurrence in those patients achieving a CR. Due to its low toxicity, this protocol can be applied at a community hospital level.