Susceptibility of Melanoma Cells to Targeted Therapy Correlates with Protection by Blood Neutrophils.

Elevated levels of peripheral blood and tumor tissue neutrophils are associated with poorer clinical response and therapy resistance in melanoma. The underlying mechanism and the role of neutrophils in targeted therapy is still not fully understood. Serum samples of patients with advanced melanoma were collected and neutrophil-associated serum markers were measured and correlated with response to targeted therapy. Blood neutrophils from healthy donors and patients with advanced melanoma were isolated, and their phenotypes, as well as their in vitro functions, were compared. In vitro functional tests were conducted through nonadherent cocultures with melanoma cells. Protection of melanoma cell lines by neutrophils was assessed under MAPK inhibition. Blood neutrophils from advanced melanoma patients exhibited lower CD16 expression compared to healthy donors. In vitro, both healthy-donor- and patient-derived neutrophils prevented melanoma cell apoptosis upon dual MAPK inhibition. The effect depended on cell-cell contact and melanoma cell susceptibility to treatment. Interference with protease activity of neutrophils prevented melanoma cell protection during treatment in cocultures. The negative correlation between neutrophils and melanoma outcomes seems to be linked to a protumoral function of neutrophils. In vitro, neutrophils exert a direct protective effect on melanoma cells during dual MAPK inhibition. This study further hints at a crucial role of neutrophil-related protease activity in protection.

Correlation of tumor PD-L1 expression in different tissue types and outcome of PD-1-based immunotherapy in metastatic melanoma - analysis of the DeCOG prospective multicenter cohort study ADOREG/TRIM.

BACKGROUND: PD-1-based immune checkpoint inhibition (ICI) is the major backbone of current melanoma therapy. Tumor PD-L1 expression represents one of few biomarkers predicting ICI therapy outcome. The objective of the present study was to systematically investigate whether the type of tumor tissue examined for PD-L1 expression has an impact on the correlation with ICI therapy outcome. METHODS: Pre-treatment tumor tissue was collected within the prospective DeCOG cohort study ADOREG/TRIM (CA209-578; NCT05750511) between February 2014 and May 2020 from 448 consecutive patients who received PD-1-based ICI for non-resectable metastatic melanoma. The primary study endpoint was best overall response (BOR), secondary endpoints were progression-free (PFS) and overall survival (OS). All endpoints were correlated with tumor PD-L1 expression (quantified with clone 28-8; cutoff ≥5%) and stratified by tissue type. FINDINGS: Tumor PD-L1 was determined in 95 primary tumors (PT; 36.8% positivity), 153 skin/subcutaneous (34.0% positivity), 115 lymph node (LN; 50.4% positivity), and 85 organ (40.8% positivity) metastases. Tumor PD-L1 correlated with BOR if determined in LN (OR = 0.319; 95% CI = 0.138-0.762; P = 0.010), but not in skin/subcutaneous metastases (OR = 0.656; 95% CI = 0.311-1.341; P = 0.26). PD-L1 positivity determined on LN metastases was associated with favorable survival (PFS, HR = 0.490; 95% CI = 0.310-0.775; P = 0.002; OS, HR = 0.519; 95% CI = 0.307-0.880; P = 0.014). PD-L1 positivity determined in PT (PFS, HR = 0.757; 95% CI = 0.467-1.226; P = 0.27; OS; HR = 0.528; 95% CI = 0.305-0.913; P = 0.032) was correlated with survival to a lesser extent. No relevant survival differences were detected by PD-L1 determined in skin/subcutaneous metastases (PFS, HR = 0.825; 95% CI = 0.555-1.226; P = 0.35; OS, HR = 1.083; 95% CI = 0.698-1.681; P = 0.72). INTERPRETATION: For PD-1-based immunotherapy in melanoma, tumor PD-L1 determined in LN metastases was stronger correlated with therapy outcome than that assessed in PT or organ metastases. PD-L1 determined in skin/subcutaneous metastases showed no outcome correlation and therefore should be used with caution for clinical decision making. FUNDING: Bristol-Myers Squibb (ADOREG/TRIM, NCT05750511); German Research Foundation (DFG; Clinician Scientist Program UMEA); Else Kröner-Fresenius-Stiftung (EKFS; Medical Scientist Academy UMESciA).

TERT expression is associated with metastasis from thin primaries, exhausted CD4+ T cells in melanoma and with DNA repair across cancer entities.

Telomerase reverse transcriptase (TERT) promoter mutations occur frequently in cancer, have been associated with increased TERT expression and cell proliferation, and could potentially influence therapeutic regimens for melanoma. As the role of TERT expression in malignant melanoma and the non-canonical functions of TERT remain understudied, we aimed to extend the current knowledge on the impact of TERT promoter mutations and expression alterations in tumor progression by analyzing several highly annotated melanoma cohorts. Using multivariate models, we found no consistent association for TERT promoter mutations or TERT expression with the survival rate in melanoma cohorts under immune checkpoint inhibition. However, the presence of CD4+ T cells increased with TERT expression and correlated with the expression of exhaustion markers. While the frequency of promoter mutations did not change with Breslow thickness, TERT expression was increased in metastases arising from thinner primaries. As single-cell RNA-sequencing (RNA-seq) showed that TERT expression was associated with genes involved in cell migration and dynamics of the extracellular matrix, this suggests a role of TERT during invasion and metastasis. Co-regulated genes found in several bulk tumors and single-cell RNA-seq cohorts also indicated non-canonical functions of TERT related to mitochondrial DNA stability and nuclear DNA repair. This pattern was also evident in glioblastoma and across other entities. Hence, our study adds to the role of TERT expression in cancer metastasis and potentially also immune resistance.

Immune checkpoint inhibition in patients with NRAS mutated and NRAS wild type melanoma: a multicenter Dermatologic Cooperative Oncology Group study on 637 patients from the prospective skin cancer registry ADOREG.

BACKGROUND: Melanomas frequently harbour somatic mutations in BRAF (40%) or NRAS (20%). Impact of NRAS mutations on the therapeutic outcome of immune checkpoint inhibitors (ICI) remains controversial. Potential correlation of the NRAS mutational status and programmed cell death ligand-1 (PD-L1) expression in melanoma is unknown. PATIENTS AND METHODS: Advanced, non-resectable melanoma patients with known NRAS mutation status treated with first-line ICI between 06/2014 and 05/2020 in the prospective multicenter skin cancer registry ADOREG were included. Overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) according to NRAS status were analysed. A multivariate Cox model was used to analyse factors associated with PFS and OS; survival was analysed using the Kaplan-Meier approach. RESULTS: Among 637 BRAF wild-type patients, 310 (49%) had an NRAS mutation with Q61R (41%) and Q61K (32%). NRAS-mutated (NRASmut) melanomas were significantly more often located on the lower extremities and trunk (p = 0.001); nodular melanoma was the most common subtype (p < 0.0001). No significant differences were found for PFS and OS for anti-PD1 monotherapy (2-year PFS 39%, [95% confidence interval (CI), 33-47] in NRASmut patients and 41% [95% CI, 35-48] in NRAS-wild type (NRASwt) patients; 2-year OS was 54% [95% CI, 48-61] in NRASmut patients and 57% [95% CI, 50-64] in NRASwt patients) and anti-PD1 plus anti-CTLA4 therapy between both cohorts (2-year PFS was 54% [95% CI, 44-66] in NRASmut patients and 53% [95% CI, 41-67] in NRASwt patients; 2-year OS was 58% [95% CI, 49-70] in NRASmut patients and 62% [95% CI, 51-75] in NRASwt patients). The ORR to anti-PD1 was 35% for NRASwt patients and 26% for NRASmut patients and 34% compared to 32% for combinational therapy. Data on PD-L1 expression was available in 82 patients (13%). PD-L1 expression (>5%) was not correlated to NRAS mutational status. In multivariate analysis, elevated lactate dehydrogenase, Eastern Cooperative Oncology Group performance status ≥ 1, and brain metastases were significantly associated with a higher risk of death in all patients. CONCLUSIONS: The PFS and OS were not affected by NRAS mutational status in patients treated with anti-PD1-based ICI. Similar ORR was seen in NRASwt and NRASmut patients. Tumour PD-L1 expression did not correlate with NRAS mutational status.

Blood Eosinophils Are Associated with Efficacy of Targeted Therapy in Patients with Advanced Melanoma.

BACKGROUND: Eosinophils appear to contribute to the efficacy of immunotherapy and their frequency was suggested as a predictive biomarker. Whether this observation could be transferred to patients treated with targeted therapy remains unknown. METHODS: Blood and serum samples of healthy controls and 216 patients with advanced melanoma were prospectively and retrospectively collected. Freshly isolated eosinophils were phenotypically characterized by flow cytometry and co-cultured in vitro with melanoma cells to assess cytotoxicity. Soluble serum markers and peripheral blood counts were used for correlative studies. RESULTS: Eosinophil-mediated cytotoxicity towards melanoma cells, as well as phenotypic characteristics, were similar when comparing healthy donors and patients. However, high relative pre-treatment eosinophil counts were significantly associated with response to MAPKi (p = 0.013). Eosinophil-mediated cytotoxicity towards melanoma cells is dose-dependent and requires proximity of eosinophils and their target in vitro. Treatment with targeted therapy in the presence of eosinophils results in an additive tumoricidal effect. Additionally, melanoma cells affected eosinophil phenotype upon co-culture. CONCLUSION: High pre-treatment eosinophil counts in advanced melanoma patients were associated with a significantly improved response to MAPKi. Functionally, eosinophils show potent cytotoxicity towards melanoma cells, which can be reinforced by MAPKi. Further studies are needed to unravel the molecular mechanisms of our observations.

MAPKinase inhibition after failure of immune checkpoint blockade in patients with advanced melanoma - An evaluation of the multicenter prospective skin cancer registry ADOREG.

OBJECTIVES: Forty to sixty percent of patients with advanced melanoma show primary resistance to PD-1-based immunotherapy, 30-40% of initial responders also progress. Here, we evaluated the outcome of second-line targeted therapy (TT) after progression on PD-1-based immune checkpoint inhibition (ICI) in BRAFV600-mutated melanoma. In addition, we report data on the activity of re-exposure with PD-1-based regimes. METHODS: Patients with advanced (non-resectable stage III or IV, AJCC 2017, 8th edition) melanoma progressing on PD-1-based ICI (nivolumab, pembrolizumab or ipilimumab plus nivolumab) and receiving second-line BRAF plus MEK inhibition were identified from the prospective multicenter skin cancer registry ADOREG. RESULTS: We identified 108 patients with unresectable stage III or stage IV melanoma progressing on first-line ICI (nivolumab, pembrolizumab or ipilimumab plus nivolumab) and receiving second-line combined BRAF/MEK inhibition. Seventy-three percent of the cohort presented with primary PD-1 resistant disease. Median progression-free survival (PFS) on ICI was 2.6 (95% CI 2.2-2.9) months. Median PFS on subsequent TT was 6.6 (95% CI 5.4-7.8) months. Median OS from start of second-line TT was 16.0 (95% CI 11.2-20.8) months. The 3-year PFS and OS rates on second-line TT were 16% and 30%. The objective response rate (ORR) and disease control rate (DCR) to TT were 42.6% and 55.6%. In patients with brain metastases, the ORR and DCR were 31.4% and 43.1%. Patients without brain metastases showed an ORR and DCR of 52.6% and 66.7%, respectively. Response to first-line ICI was associated with a numerically higher ORR and DCR to second-line TT and improved OS on TT. Twenty-three patients received third-line ICI of whom two patients showed an objective response. CONCLUSIONS: BRAF plus MEK inhibition shows meaningful activity and outcome in patients with advanced melanoma resistant to anti-PD-1-based immunotherapy. Rates of long-term benefit and survival in our study were similar to those reported for treatment-naïve patients receiving first-line MAPKi.

Efficacy of PD-1-based immunotherapy after radiologic progression on targeted therapy in stage IV melanoma.

OBJECTIVES: Targeted therapy (TT) is an effective treatment for advanced BRAFV600-mutated melanoma, but most patients eventually acquire resistance and progress. Here, we evaluated the outcome of second-line immune checkpoint blockade (ICB) after progression on dual BRAF and MEK inhibition. METHODS: Patients with metastatic melanoma progressing on combined BRAF + MEK inhibition and receiving second-line ICB between 2015 and 2019 in 9 tertiary referral centres were enrolled. Demographic and clinical data and blood counts of all patients were collected retrospectively. RESULTS: We identified 99 patients with stage IV melanoma receiving ICB (nivolumab, pembrolizumab [n = 39] or ipilimumab plus nivolumab [n = 60]) after progression on combined TT. The median progression-free survival was similar in the PD-1 and ipilimumab plus nivolumab group (2.6 months [95% confidence interval {CI}, 2.0-3.1] vs. 2.0 [95% CI, 1.4-2.6], p = 0.15). The objective response rate was 18.0% in the PD-1 and 15.0% in the ipilimumab plus nivolumab group (p = 0.70). The disease control rate was 25.7% for monotherapy and 18.3% for combined ICB (p = 0.39). The median overall survival was 8.4 months (95% CI, 5.1-11.7) for patients receiving PD-1 monotherapy and 7.2 months (95% CI, 5.2-9.1) for patients receiving ipilimumab plus nivolumab (p = 0.86). The latter was associated with a higher rate of treatment-related adverse events (AEs). No significant association of laboratory values or clinicopathological characteristics with response to second-line ICB was observed. CONCLUSIONS: PD-1 monotherapy and combined ipilimumab plus nivolumab show similar activity and outcome in patients with melanoma resistant to BRAF + MEK inhibition. However, combined ipilimumab plus nivolumab was associated with a higher rate of treatment-related AEs compared with monotherapy.

Patterns of disease control and survival in patients with melanoma brain metastases undergoing immune-checkpoint blockade.

OBJECTIVES: Immune-checkpoint blockers (ICBs) significantly prolong overall survival (OS) in patients with advanced melanoma. Limited data are available on the efficacy and clinical benefit in patients with melanoma brain metastases (MBMs). The aim of this study was to determine whether ICB is active in an unselected cohort treated of patients with known brain metastases and if disease control correlates with the survival. METHODS: A total of 385 patients with metastatic malignant melanoma treated with ICB as monotherapy between 2005 and 2017 in two tertiary referral centres were included. Patient records were searched for the development of brain metastases. Demographic and clinical data of all patients were collected retrospectively. RESULTS: We identified 177 patients with MBM who received ICBs (ipilimumab, nivolumab, pembrolizumab). Patients with and without brain metastases received similar ICB regimens. Prognosis was inferior in patients with brain metastases; patients with >1 brain metastasis showed even poorer survival. For extracranial (ec) metastases, disease control was associated with improved survival. However, when comparing patients with intracranial (ic) disease control during immunotherapy to patients with ic disease progression, no difference in OS could be observed. CONCLUSIONS: In our study, ec disease control was the dominant predictive factor for OS in both patients with or without melanoma brain metastases. These data indicate that clinical trials in melanoma patients with brain metastases should address end-points such as symptom control, quality of life or OS in addition to ic response rates.