Melanoma Brain Metastases Patients Research Articles

Abstract 4031: P-selectin as an emerging target for the treatment of primary and secondary brain tumors

Abstract Glioblastoma (GB) is an aggressive type of brain cancer with a high mortality rate. It is a highly angiogenic tumor exhibiting an extremely invasive nature. As such, its brain microenvironment plays a crucial role in its progression. Microglia are the brain resident immune cells that have been shown to facilitate GB cell invasion and immune suppression. The mechanism by which GB cells alter microglia behavior is yet to be fully understood. One proposed mechanism involves adhesion molecules such as the Selectins family of proteins which are expressed on the surface of endothelial and immune cells and are involved in immune modulation and cancer immunity. We have previously shown that one member of the Selectin family, P-Selectin (SELP), is expressed by GB cells. Here, we investigated the functional role of SELP in GB-microglia interactions. First, we found that microglia cells facilitate the expression and secretion of SELP by GB cells, and that GB cells facilitate the expression of P-Selectin ligand-1 (PSGL-1) by Glioma-associated microglia/macrophages (GAMs). We then showed that SELP mediates GAMs-enhanced GB invasion and proliferation in our unique 3D-bioprinted ex vitro models and has a role in GAMs activation state. These findings were validated in vivo, showing that inhibition or downregulation of SELP leads to reduced tumor growth, increased overall survival, and improved immune response. Single-cell RNA-seq analysis of the tumors revealed an increase in pro-inflammatory GAMs signature, reduction in cancer cell tumorigenesis potential, and improved T cell activation. Thus, combining SELP inhibition with other immune checkpoint inhibitors, such as anti-PD-1, may have a synergistic effect by harnessing both the innate and the adaptive immune systems against the tumor. Furthermore, we found SELP/PSGL-1 axis to be involved in the progression of brain metastasis originating from melanoma, and breast, and lung cancer. Thus, we have begun an investigator-initiated clinical trial, testing the efficacy of the anti-SELP antibody, Crizanlizumab, alone or in combination with anti-PD-1 antibody, Nivolumab, for GB and melanoma brain metastasis patients (NCT05909618). Crizanlizumab, approved by the FDA and EMA for sickle cell pain crisis (VOC, Vaso-Occlusive Crisis) of sickle-cell anemia patients, was proven to be safe for human use, and efficient in inhibiting SELP function. As such, it has the potential to reduce tumor burden and improve patient outcomes. This work can improve our understanding of GAMs function, which may pave the way for new and effective treatments for primary and secondary brain tumors. Citation Format: Eilam Yeini, Ronnie Frommer-Shapira, Alisa Talianski, Paula Ofek, Sabina Pozzi, Nitzan Albeck, Dikla Ben-Shushan, Galia Tiram, Sapir Golan, Ron Kleiner, Ron Sheinin, Shlomit Reich-Zeliger, Rachel Grossman, Zvi Ram, Henry Brem, Thomas M. Hyde, Prerna Magod, Dinorah Friedmann-Morvinski, Asaf Madi, Ronit Satchi-Fainaro. P-selectin as an emerging target for the treatment of primary and secondary brain tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4031.

A single-center retrospective analysis of prognoses in patients with melanoma brain metastases and effectiveness of treatment in Japan.

Melanoma brain metastasis (MBM) has a poor prognosis, although recent treatments, including immune checkpoint inhibitors and targeted therapy, have improved the prognosis. However, these systemic therapies have been reported to be less efficient for Asian patients. We investigated the survival of Asian patients with MBM and the effectiveness of systemic therapies. We retrospectively reviewed the survival rates of patients diagnosed with MBM between January 2011 and December 2021 at the National Cancer Center Hospital in Tokyo, Japan. In addition, we identified factors associated with survival using Cox regression analysis. A total of 135 patients were included. The median overall survival (OS) after an MBM diagnosis was 7.8 months (95% confidence interval [CI] 6.1-9.6). The 6-month and 1-year survival rates were 60.7% and 34.8%, respectively. We identified the prognostic factors of MBM, including non-acral primary location, low serum LDH levels, systemic therapy of single-agent immune checkpoint inhibitors (ICIs) or targeted therapies (TTs), and radiotherapy of stereotactic irradiation (STI). We found no significant difference in effectiveness between single-agent ICIs, the combination of Nivolumab and Ipilimumab (COMBI-ICI), and TTs (COMBI-ICI vs. single-agent ICI, hazard ratio 0.71, 95% confidence interval 0.27-1.88, p = 0.49; COMBI-ICI vs. TT: hazard ratio 0.46, 95% confidence interval 0.14-1.55, p = 0.21). Systemic therapy and radiotherapy have improved the survival of MBM patients, but the survival of Asian patients remains poor. Our findings suggest that COMBI-ICIs are not significantly more effective than single-agent ICI or TT in treating MBM.

MODL-06. THE GUT MICROBIOTA OF BRAIN TUMOR PATIENTS CAN IMPACT IMMUNOTHERAPY EFFICACY IN A PRECLINICAL MODEL OF GLIOMA

Abstract Combination immune checkpoint inhibitors (ICI) can affect durable response in melanoma brain metastases (MBM) but have largely been ineffective for the treatment of glioblastoma (GBM), a primary brain tumor. Recent studies in animal models and humans have suggested that the microbe composition of the gut can influence the effectiveness of ICI in melanoma and other cancers. Our central hypothesis is that the gut microbiome can influence immunotherapy responsiveness for GBM patients. We obtained microbiome (stool) samples from GBM and MBM patients prior to beginning any treatment or surgical interventions. We then transplanted these microbiome samples into gnotobiotic mice to create humanized microbiome mice. We transplanted two GBM patients and two MBM patients microbiome samples to create 4 unique patient-derived humanized microbiome mouse lines (GBM1, GBM2, MBM1, and MBM2). Using 16s ribosomal RNA microbiome sequencing, we found that each patient-derived microbiome mouse line had a unique microbiome composition as measured by relative abundance and diversity of species. Mice from each line were then intracranially injected with GL261 murine glioma cells and treated with the ICI anti-PD-1 or isotype control. We found that MBM1 and GBM2 mice were resistant to anti-PD-1 and did not display prolonged survival with anti-PD-1 treatment. However, GBM1 and MBM2 mice were positive responders to anti-PD-1 and displayed significantly prolonged survival compared to isotype control. Additional microbiome sequencing analyses are ongoing that will reveal positive microbiome profiles among these patient-derived lines, and additional GBM and MBM patient-derived microbiome lines are being created and tested for immunotherapy efficacy. Ultimately, understanding how certain microbial communities can enhance the effectiveness of immunotherapy may lead to the development of new approaches that include modification or transplantation of microbe communities in GBM patients for increased therapeutic impact.

P06.01.A HAS THE USE OF DUAL AGENT IMMUNOTHERAPY BEEN ALTERING THE INCIDENCE OF MELANOMA BRAIN METASTASES? A POPULATION-LEVEL ANALYSIS AND SINGLE-INSTITUTION VALIDATION

Abstract BACKGROUND Dual agent immunotherapy (dIT) has revolutionized the treatment of advanced melanoma, with recent clinical trials demonstrating its effectiveness in managing small, asymptomatic melanoma brain metastases (MBM) in the upfront setting. However, its potential role in preventing MBM has not been thoroughly investigated. MATERIAL AND METHODS A retrospective analysis was performed on the TriNetX database, which compiles clinical data from 92 healthcare organizations. Melanoma patients without MBM at diagnosis were divided into two groups: those who received ipilimumab alone (single immunotherapy, sIT) and those who received ipilimumab and nivolumab (dIT). The study compared the frequency of new asynchronous MBM diagnosis among the cohorts and analyzed the median overall survival (OS) of MBM patients using Kaplan Meier analysis and log-rank tests. Additionally, a retrospective cohort validation study was conducted on a sample of randomly selected patients treated at a single institution between 2012-2019. Electronic medical records were reviewed for demographics, melanoma treatment history, and clinical outcomes. RESULTS TriNetX identified a total of 732,555 melanoma patients, including 717,408 who did not receive immunotherapy (no-IT), 4,585 who received dual immunotherapy (dIT), and 4,101 who received single immunotherapy (sIT). The mean ages at melanoma brain metastases (MBM) diagnosis were 66.9, 61.5, and 63.2 years for each respective group. The prevalence of MBM was 1.5%, 9.6%, and 15.6% for no-IT, dIT, and sIT groups, respectively (p < 0.0001). DIT was associated with a lower rate of MBM compared to sIT(OR [95%CI], 0.64 [0.61-0.77]). After propensity score matching, the median overall survival for MBM patients was not statistically different between the no-IT, dIT, and sIT groups (347, 400, 414 days, respectively). In the validation group of 90 patients (30 no-IT, 27 sIT, 34 dIT), predominantly male (61.5%), stage III (62.5%), the prevalence of MBM was 13.8%, 59%, and 38.2% for each respective group for developing MBM (OR [95%CI], 2.35 [0.84-6.60], p=0.08). The mean time between immunotherapy initiation and MBM was 305 days for dIT and 500 days for sIT for patients who developed MBM. CONCLUSION The results suggest that using a combination of ipilimumab and nivolumab immunotherapy could be effective in reducing the incidence of brain metastases in advanced melanoma patients. Further investigation is needed to explore the potential preventive role of dIT in MBM development in this patient population.

Toxicity and outcomes of melanoma brain metastases treated with stereotactic radiosurgery: the risk of subsequent symptomatic intralesional hemorrhage exceeds that of radiation necrosis.

We aimed to assess the outcomes and patterns of toxicity in patients with melanoma brain metastases (MBM) treated with stereotactic radiosurgery (SRS) with or without immunotherapy (IO). From a prospective registry, we reviewed MBM patients treated with single fraction Gamma Knife SRS between 2008 and 2021 at our center. We recorded all systemic therapies (chemotherapy, targeted therapy, or immunotherapy) administered before, during, or after SRS. Patients with prior brain surgery were excluded. We captured adverse events following SRS, including intralesional hemorrhage (IH), radiation necrosis (RN) and local failure (LF), as well as extracranial disease status. Distant brain failure (DBF), extracranial progression-free survival (PFS) and overall survival (OS) were determined using a cumulative Incidence function and the Kaplan-Meier method. Our analysis included 165 patients with 570 SRS-treated MBM. Median OS for patients who received IO was 1.41 years versus 0.79 years in patients who did not (p = 0.04). Ipilimumab monotherapy was the most frequent IO regimen (30%). In the absence of IO, the cumulative incidence of symptomatic (grade 2 +) RN was 3% at 24 months and remained unchanged with respect to the type or timing of IO. The incidence of post-SRS g2 + IH in patients who did not receive systemic therapy was 19% at 1- and 2 years compared to 7% at 1- and 2 years among patients who did (HR: 0.33, 95% CI 0.11-0.98; p = 0.046). Overall, neither timing nor type of IO correlated to rates of DBF, OS, or LF. Among patients treated with IO, the median time to extracranial PFS was 5.4 months (95% IC 3.2 - 9.1). The risk of g2 + IH exceeds that of g2 + RN in MBM patients undergoing SRS, with or without IO. IH should be considered a critical adverse event following MBM treatments.

Estimating survival in patients with melanoma brain metastases: prognostic value of lactate dehydrogenase.

Patients with melanoma brain metastases (MBM) have poor prognosis, albeit advances in locoregional and systemic treatments. The melanoma-specific Graded Prognostic Assessment (GPA) effectively stratifies survival for patients with MBM. Nevertheless, lactate dehydrogenase (LDH), a well known prognostic factor for patients with melanoma, is not represented in the GPA scores and might add prognostic information for patients with MBM. In this study, 150 consecutive patients with MBM were retrospectively analyzed with the aim of evaluating independent prognostic factors for MBM patients, including LDH. Furthermore, we implemented a disease-specific prognostic score and estimated survival according to treatment modalities. On the basis of multivariable Cox regression analyses, six prognostic factors (age, BRAF status, number of MBM, number of extracranial metastatic sites, performance status, and LDH level) resulted statistically significant in terms of survival and were combined in a prognostic score to stratify patients in distinct prognostic groups ( P  < 0.0001). Among treatment modalities, a multimodal approach with stereotactic radiosurgery or neurosurgery associated with systemic therapy showed the best outcome (median overall survival: 12.32 months, 95% confidence interval, 7.92-25.30). This is the first study to demonstrate that LDH has independent prognostic value for patients with MBM and might be used to improve prognostic stratification, albeit external validation is mandatory. Survival of patients with MBM is affected by both disease-specific risk factors and treatment modalities, with locoregional treatments associated with better outcomes.

Health-related quality of life in patients with melanoma brain metastases treated with immunotherapy.

Aims: To describe the health-related quality of life (HRQoL) of melanoma brain metastasis (MBM) patients throughout the first 18weeks of ipilimumab-nivolumab or nivolumab treatment. Materials & methods: HRQoL data (European Organisation for Research and Treatment of Cancer'sCore Quality of Life Questionnaire, additional Brain Neoplasm Module, and EuroQol 5-Dimension 5-Level Questionnaire) were collected as a secondary outcome of the Anti-PD1 Brain Collaboration phase II trial. Mixed linear modeling assessed changes over time, whereas the Kaplan-Meier method was used to determine median time to first deterioration. Results: Asymptomatic MBM patients treated with ipilimumab-nivolumab (n=33) or nivolumab (n=24) maintained baseline HRQoL. MBM patients with symptoms or leptomeningeal/progressive disease treated with nivolumab (n=14) reported a statistically significant trend toward improvement. Conclusion: MBM patients treated with either ipilimumab-nivolumab or nivolumab did not report a significant deterioration in HRQoL within 18weeks of treatment initiation. Clinical trial registration: NCT02374242 (ClinicalTrials.gov).

Changes in outcomes and factors associated with survival in melanoma patients with brain metastases.

Treatment options for patients with melanoma brain metastasis (MBM) have changed significantly in the last decade. Few studies have evaluated changes in outcomes and factors associated with survival in MBM patients over time. The aim of this study is to evaluate changes in clinical features and overall survival (OS) for MBM patients. Patients diagnosed with MBMs from 1/1/2009 to 12/31/2013 (Prior Era; PE) and 1/1/2014 to 12/31/2018 (Current Era; CE) at The University of Texas MD Anderson Cancer Center were included in this retrospective analysis. The primary outcome measure was OS. Log-rank test assessed differences between groups; multivariable analyses were performed with Cox proportional hazards models and recursive partitioning analysis (RPA). A total of 791 MBM patients (PE, n=332; CE, n=459) were included in analysis. Median OS from MBM diagnosis was 10.3months (95% CI, 8.9-12.4) and improved in the CE vs PE (14.4 vs 10.3months, P<.001). Elevated serum lactate dehydrogenase (LDH) was the only factor associated with worse OS in both PE and CE patients. Factors associated with survival in CE MBM patients included patient age, primary tumor Breslow thickness, prior immunotherapy, leptomeningeal disease, symptomatic MBMs, and whole brain radiation therapy. Several factors associated with OS in the PE were not significant in the CE. RPA demonstrated that elevated serum LDH and prior immunotherapy treatment are the most important determinants of survival in CE MBM patients. OS and factors associated with OS have changed for MBM patients. This information can inform contemporary patient management and clinical investigations.

Melanoma central nervous system metastases: An update to approaches, challenges, and opportunities.

Brain metastases are the most common brain malignancy. This review discusses the studies presented at the third annual meeting of the Melanoma Research Foundation in the context of other recent reports on the biology and treatment of melanoma brain metastases (MBM). Although symptomatic MBM patients were historically excluded from immunotherapy trials, efforts from clinicians and patient advocates have resulted in more inclusive and even dedicated clinical trials for MBM patients. The results of checkpoint inhibitor trials were discussed in conversation with current standards of care for MBM patients, including steroids, radiotherapy, and targeted therapy. Advances in the basic scientific understanding of MBM, including the role of astrocytes and metabolic adaptations to the brain microenvironment, are exposing new vulnerabilities which could be exploited for therapeutic purposes. Technical advances including single-cell omics and multiplex imaging are expanding our understanding of the MBM ecosystem and its response to therapy. This unprecedented level of spatial and temporal resolution is expected to dramatically advance the field in the coming years and render novel treatment approaches that might improve MBM patient outcomes.

P11.23.B Neurological symptoms independently associate with overall survival in patients with melanoma brain metastases

Abstract Background Based on the the rising detection of asymptomatic brain metastases (BM) and the remarkable intracranial responses of targeted- and immunotherapy in specific subgroups of asymptomatic BM patients, we aimed to evaluate the clinical characteristics and prognostic value of neurological symptoms in BM from melanoma. Material and Methods 670 patients with newly diagnosed melanoma BM were identified from the Vienna Brain Metastasis Registry. We performed retrospective chart review and statistical outcome analyses. Results 370/670 (55.2%) patients presented with neurological symptoms including neurological deficits (316/370; 85.4%), signs of increased intracranial pressure (126/370; 34.1%) and epileptic seizures (53/370; 14.3%). 57.6% (80/139) of patients with BRAF mutated melanoma presented with asymptomatic BM at diagnosis. Absence of neurological symptoms at BM diagnosis was associated with a longer median overall survival after time of BM diagnosis (7 vs. 5 months; p&amp;lt; 0.001; log-rank test). In multivariate analysis with the diagnosis-specific graded prognostic assessment (DS-GPA: HR:1.4; 95% CI, 1.25-1.48; p&amp;lt;0.001) and the graded prognostic assessment for melanoma using molecular markers (Melanoma-molGPA: HR:0.8; 95% CI, 0.66 -0.92; p&amp;lt;0.001), the presence of neurological symptoms (HR 0.8; 95% CI, 0.69 -0.96; p=0.003/ HR:0.6; 95% CI, 0.59-0.72; p&amp;lt;0.001) was found to be independently associated with survival prognosis from time of BM diagnosis respectively. Conclusion: Neurological symptoms at the time of BM diagnosis are an independent and strong prognostic factor in melanoma BM patients. Our results argue for the integration of neurological symptoms into the prognostic assessment of patients with BM from melanoma.

CLRM-11 CURRENT STATE OF CLINICAL TRIALS FOR PATIENTS WITH MELANOMA BRAIN METASTASES

INTRODUCTIONClinical trials have traditionally excluded patients with melanoma brain metastasis (MBM), despite evidence of CNS activity of systemic therapy. The true extent of variation in MBM-related enrollment criteria in ongoing melanoma clinical trials has not been evaluated. METHODSA systematic search of clinicaltrials.gov website was performed to characterize trends in clinical trial enrollment of MBM patients in interventional drug trials. Trial data search was limited to “open”, “interventional studies” and advanced stage melanoma in adult patients. Logistic regression was used to model inclusion of active MBMs. Covariates considered were phase of study, location, therapy type, melanoma specific, and sponsor category RESULTSOf a total of 475 trials identified, 365 met inclusion criteria. 230 (63.0%) were phase I, 119 (32.6%) were phase II, 14 (3.8%) were phase III and 2 (0.5%) were phase IV trials. 184 (50.4%) were pharmaceutical industry sponsored, 183 (50.1%) were specific for melanoma. Forty-seven (12.8%) trials strictly excluded brain metastasis and 173 (47.3%) strictly excluded leptomeningeal disease (LMD). 261 (71.5%) trials allowed patients with previously treated MBM, and 73 (20.0%) allowed patients with active MBMs. No explicit mention of CNS metastasis was made in 13.6% of trials and no mention of LMD was made in 43.8% trials. In univariate models, trials not employing immunotherapy (odds ratio 2.23; 95% CI: 1.2, 4.3; p = 0.0174) and non-pharma trials (odds ratio 1.98; 95% CI 1.0, 3.9; p= 0.0461) were twice as likely to include MBM patients. In a combined model, only therapy type remained significant at the α=0.05 level. CONCLUSIONDespite the evidence of CNS activity of immunotherapy in randomized trials, only 20% ongoing trials are enrolling patients with active MBMs. Efforts should be made to tailor future clinical trial designs to include MBM patients to assess CNS activity of systemic therapeutics early on in drug development.

Impact of radiotherapy and sequencing of systemic therapy on survival outcomes in melanoma patients with previously untreated brain metastasis: a multicenter DeCOG study on 450 patients from the prospective skin cancer registry ADOREG

BackgroundDespite of various therapeutic strategies, treatment of patients with melanoma brain metastasis (MBM) still is a major challenge. This study aimed at investigating the impact of type and sequence of...

The role of systemic therapy in melanoma brain metastases: a narrative review.

Melanoma is a disease notorious for the development of brain metastases, with consequently poor outcomes for patients who develop melanoma brain metastases (MBM). The treatment options for patients with MBM were limited to radiotherapy and surgery. MBM patients, particularly those with symptomatic disease, were excluded from clinical trials of immune checkpoint inhibitors (ICI) and BRAF/MEK inhibitors. Recent post-approval studies have, demonstrated important roles for existing systemic ICIs and BRAF/MEK inhibitors in untreated MBM, dramatically altering the landscape of melanoma patients in general and MBM in particular. These trials have also identified key areas for which more effective strategies are needed including: symptomatic MBM, and leptomeningeal disease (LMD). PubMed, Scopus and Embase databases were systematically queried to obtain records pertaining to the etiology of and treatment for MBM. Clinical trial databases were reviewed to obtain details regarding MBM clinical trials. We discuss the etiopathogenesis of MBM and the novel immune, molecular and metabolic features of MBM that make this disease a unique therapeutic challenge. We review advances in systemic therapy with ICIs and BRAF/MEK inhibitors in untreated MBM, along with novel combinations. Finally, we debate challenging situations such as LMD, and delineate novel treatments and new paradigms for therapeutic interventions. The historically poor outcomes for MBM patients have been transformed with the advent of effective systemic therapies including ICIs and BRAF/MEK inhibitors. An improved understanding of the molecular and immunogenomic characterization of MBMs has provided new targets that are being exploited in the clinic.

Evaluation of radio-immunotherapy sequence on immunological responses and clinical outcomes in patients with melanoma brain metastases (ELEKTRA)

ABSTRACT In patients with melanoma brain metastases (MBM), a combination of radiotherapy (RT) with immune checkpoint inhibitors (ICI) is routinely used. However, the best sequence of radio-immunotherapy (RIT) remains unclear. In an exploratory phase 2 trial, MBM patients received RT (stereotactic or whole-brain radiotherapy depending on the number of MBM) combined with ipilimumab (ipi) ± nivolumab (nivo) in different sequencing (Rad-ICI or ICI-Rad). Comparators arms included patients treated with ipi-free systemic treatment or without RT (in MBM-free patients). The primary endpoints were radiological and immunological responses in the peripheral blood. Secondary endpoints were progression-free survival (PFS) and overall survival (OS). Of 106 screened, 92 patients were included in the study. Multivariate analysis revealed an advantage for patients starting with RT (Rad-ICI) for overall response rate (RR: p = .007; HR: 7.88 (95%CI: 1.76–35.27)) and disease control rate (DCR: p = .036; HR: 6.26 (95%CI: 1.13–34.71)) with a trend for a better PFS (p = .162; HR: 1.64 (95%CI: 0.8–3.3)). After RT plus two cycles of ipi-based ICI in both RIT sequences, increased frequencies of activated CD4, CD8 T cells and an increase in melanoma-specific T cell responses were observed in the peripheral blood. Lasso regression analysis revealed a significant clinical benefit for patients treated with Rad-ICI sequence and immunological features, including high frequencies of memory T cells and activated CD8 T cells in the blood. This study supports increasing evidence that sequencing RT followed by ICI treatment may have better effects on the immunological responses and clinical outcomes in MBM patients.

P14.25 Melanoma brain metastases in the era of novel therapies: a single-center, Dutch cohort study

Abstract BACKGROUND Until recently, patients with melanoma brain metastases (MBMs) had limited therapeutic options. With the arrival of immune checkpoint inhibitors (ICIs), targeted therapy (TT) and advances in stereotactic radiotherapy (SRT), treatment has improved. We evaluated treatments and patient outcome before and after the introduction of these novel therapies. MATERIAL AND METHODS In this retrospective, single-center study, patients presenting with MBMs at the Erasmus MC between November 2005 and January 2021 with sufficient follow-up were included. Overall survival (OS), measured from date of MBM diagnosis, was calculated using the Kaplan-Meier method. Patients were stratified according to MBM diagnosis before and after January 1, 2016, since novel therapies were mostly prescribed in our clinic after this date. Results were significant (p&amp;lt;0.05), unless otherwise stated. RESULTS Overall, 413 patients were included. Median [IQR] age was 56.6 years [52–71] with a 60% male predominance. A BRAF mutation was present in 46.7% of patients. A single MBM was found in 29.3% and ≥4 MBMs were found in 49.0% of patients. Before January 1, 2016, 191 patients were treated, and 222 patients after that date. Chemotherapy was more frequently used before 2016, both prior to (3.9% pre-2016 vs. 0.9% post-2016) and after (7.0% vs. 0.0%) the diagnosis of MBMs. In contrast, treatment with TT was more frequent after 2016, both prior to (3.7% vs. 16.2%) and after (7.9% vs. 41.4%) the diagnosis of MBMs. Comparable changes were observed for treatment with ICIs (prior to MBM diagnosis: 0.5% vs. 25.2%; after MBM diagnosis: 18.3% vs 39.2%). The application of SRT did not differ significantly before and after 2016 (12.0% vs. 19.4%, p=0.89), while the application of whole brain radiotherapy (WBRT) decreased (52.4% vs. 13.5%). Surgical resection was not significantly different between those periods (15.7% vs. 16.7%, p=0.90). Before 2016, median OS [IQR] was shorter than after 2016 (4.6 [1.9–10.9] vs. 6.6 [1.8–24.5] months). The effect of novel therapies on OS was further analysed in patients diagnosed after 2016; treatment vs. no treatment was compared. ICI treatment prior to MBM diagnosis was associated with worse OS (median OS 4.0 vs. 7.5 months). ICI treatment after MBM diagnosis was associated with better OS (median OS 24.5 vs. 3.0 months). In patients with a BRAF mutation, TT before MBM diagnosis was associated with worse OS (median OS 1.8 vs. 9.4 months). TT after MBM diagnosis in those patients was not significantly associated with improved OS (median OS 7.6 vs. 5.2 months, p=0.96). CONCLUSION Recent therapeutic advances for MBM replaced WBRT and chemotherapy with SRT, TT and ICIs. In that period, prognosis of MBM patients increased significantly. OS in patients treated with ICIs or TT prior to MBM diagnosis is still poor, but OS is improved in patients treated with ICIs after the diagnosis of MBM.

Single-Cell Characterization of the Immune Microenvironment of Melanoma Brain and Leptomeningeal Metastases.

Melanoma brain metastases (MBM) and leptomeningeal melanoma metastases (LMM) are two different manifestations of melanoma CNS metastasis. Here, we used single-cell RNA sequencing (scRNA-seq) to define the immune landscape of MBM, LMM, and melanoma skin metastases. scRNA-seq was undertaken on 43 patient specimens, including 8 skin metastases, 14 MBM, and 19 serial LMM specimens. Detailed cell type curation was performed, the immune landscapes were mapped, and key results were validated by IHC and flow cytometry. Association analyses were undertaken to identify immune cell subsets correlated with overall survival. The LMM microenvironment was characterized by an immune-suppressed T-cell landscape distinct from that of brain and skin metastases. An LMM patient with long-term survival demonstrated an immune repertoire distinct from that of poor survivors and more similar to normal cerebrospinal fluid (CSF). Upon response to PD-1 therapy, this extreme responder showed increased levels of T cells and dendritic cells in their CSF, whereas poor survivors showed little improvement in their T-cell responses. In MBM patients, therapy led to increased immune infiltrate, with similar T-cell transcriptional diversity noted between skin metastases and MBM. A correlation analysis across the entire immune landscape identified the presence of a rare population of dendritic cells (DC3) that was associated with increased overall survival and positively regulated the immune environment through modulation of activated T cells and MHC expression. Our study provides the first atlas of two distinct sites of melanoma CNS metastases and defines the immune cell landscape that underlies the biology of this devastating disease.

Ipilimumab and Stereotactic Radiosurgery with CyberKnife® System in Melanoma Brain Metastases: A Retrospective Monoinstitutional Experience.

Simple SummaryRetrospective studies have shown a survival advantage in combining ipilimumab with radiotherapy in patients with melanoma brain metastases (MBMs). However, these studies did not clarify the correct timing between the two methods. The aims of our study were to demonstrate the efficacy and toxicity of stereotactic radiotherapy/radiosurgery on MBMs in combination with ipilimumab and estimate the correct timing of treatments to improve patients’ outcomes.The median overall survival (OS) and local control (LC) of patients with melanoma brain metastases (MBMs) are poor even with immune checkpoint inhibitors and/or radiotherapy (RT). The aims of the study were to evaluate the association and timing of stereotactic radiotherapy (SRT)/radiosurgery (SRS) performed with the CyberKnife® System and ipilimumab (IPI). A total of 63 MBMs patients were analyzed: 53 received RT+IPI and 10 RT alone. Therefore, the patients were divided into four groups: RT PRE-PI (>4 weeks before IPI) (18), RT CONC-IPI (4 weeks before/between first and last cycle/within 3 months of last cycle of IPI) (20), RT POST-IPI (>3 months after IPI) (15), and NO-IPI (10). A total of 127 lesions were treated: 75 with SRS (one fraction) and 24 with SRT (three to five fractions). The median follow-up was 10.6 months. The median OS was 10.6 months for all patients, 10.7 months for RT+IPI, and 3.3 months for NO-IPI (p = 0.96). One-year LC was 50% for all patients, 56% for RT+IPI, and 18% for NO-IPI (p = 0.08). The 1-year intracranial control was 45% for all patients, 44% for RT+IPI, and 51% for NO-IPI (p = 0.73). IPI with SRS/SRT in MBMs treatment could improve LC. However, the impact and timing of the two modalities on patients’ outcomes are still unclear.

A Contemporary Report of Clinical Outcomes in Patients with Melanoma Brain Metastases.

Background: Brain metastases are observed in more than 40% of all patients with stage 4 melanoma. In recent years, more extensive use of stereotactic radiation (STRT) and the advent of immune checkpoint inhibitors have positively impacted outcomes in patients with metastatic melanoma.brain metastases. Here, we examined real world clinical outcomes of patients presenting with melanoma brain metastases (MBMs). Methods: This retrospective review evaluated MBMs patients treated at The Ottawa Hospital from April 2000 to July 2017. Clinical, radiologic, pathologic and treatment information were gathered from the electronic medical records. The primary outcome was overall survival. The proportional Cox regression model was employed for survival data, while the Fisher’s exact and Mann–Whitney U tests analyzed the relationship between categorical and continuous data, respectively. Results: This retrospective study included 276 patients. Brain metastases were detected symptomatically in 191 patients (69.2%); the rates of detection by routine screening were 4.6% in the pre-2012 era and 11.7% in the contemporary era (p = 0.029). Median survival was three months. Predictors of overall survival were age, higher lactate dehydrogenase (LDH) values, multiple brain lesions, more extensive extracranial disease, neurological symptoms, infratentorial lesions and treatment type. Multivariable analysis demonstrated that stereotactic radiotherapy (STRT) was associated with a hazard ratio of 0.401 (p < 0.001) for survival; likewise, immune checkpoint inhibitor therapy was associated with a hazard ratio of 0.375 (p < 0.001). Conclusion: The findings from this study as “real world” data are consistent with results of pivotal clinical trials in MBMs patients and support contemporary locoregional and immunotherapy practices.

Clinical, molecular, metabolic, and immune features associated with oxidative phosphorylation in melanoma brain metastases.

BackgroundRecently, we showed that melanoma brain metastases (MBMs) are characterized by increased utilization of the oxidative phosphorylation (OXPHOS) metabolic pathway compared to melanoma extracranial metastases (ECMs). MBM growth was inhibited by a potent direct OXPHOS inhibitor, but observed toxicities support the need to identify alternative therapeutic strategies. Thus, we explored the features associated with OXPHOS to improve our understanding of the pathogenesis and potential therapeutic vulnerabilities of MBMs.MethodsWe applied an OXPHOS gene signature to our cohort of surgically resected MBMs that had undergone RNA-sequencing (RNA-seq) (n = 88). Clustering by curated gene sets identified MBMs with significant enrichment (High-OXPHOS; n = 21) and depletion (Low-OXPHOS; n = 25) of OXPHOS genes. Clinical data, RNA-seq analysis, and immunohistochemistry were utilized to identify significant clinical, molecular, metabolic, and immune associations with OXPHOS in MBMs. Preclinical models were used to further compare melanomas with High- and Low-OXPHOS and for functional validation.ResultsHigh-OXPHOS MBMs were associated with shorter survival from craniotomy compared to Low-OXPHOS MBMs. High-OXPHOS MBMs exhibited an increase in glutamine metabolism, and treatment with the glutaminase inhibitor CB839 improved survival in mice with MAPKi-resistant, High-OXPHOS intracranial xenografts. High-OXPHOS MBMs also exhibited a transcriptional signature of deficient immune activation, which was reversed in B16-F10 intracranial tumors with metformin treatment, an OXPHOS inhibitor.ConclusionsOXPHOS is associated with distinct clinical, molecular, metabolic, and immune phenotypes in MBMs. These associations suggest rational therapeutic strategies for further testing to improve outcomes in MBM patients.

Abstract PR19: Monitoring of melanoma progression utilizing multiplatform biomarkers of blood cell-free DNA

Abstract Blood biopsies utilizing cell-free DNA (cfDNA) represent an alternative, minimally invasive source that permits repeated sampling to enable melanoma patient monitoring during treatment and follow-up. However, the sensitivity of cfDNA biomarker detection is limited to tumor sampling availability, which can vary significantly. This encourages the use of multiplatform biomarkers to improve sensitivity in assessing melanoma progression. Here we explored the detection of different cfDNA biomarker types, DNA mutations and copy number amplification (CNA), in blood of melanoma patients. To assess the utility of these cfDNA biomarker types, we utilized a highly sensitive multigene (54-gene cancer panel) digital next-generation sequencing (NGS) assay containing 0.1% sensitivity or multiplex droplet digital PCR ddPCR. cfDNA mutations were assessed by a multigene digital NGS assay in a cohort of preoperative stage III/IV patients rendered disease-free (n=44), whereby 75% of patients had detectable cfDNA genomic aberrations. Patients with high tumor mutation burden (TMB) (≥3 mutations) were associated with worse overall survival (OS) (p=0.048) compared to those with &amp;lt;3 mutations. Next, we assessed 98 serial bleeds obtained from a cohort of preoperative stage IIIA-C melanoma patients rendered disease-free followed by adjuvant immunotherapy with follow-up until stage IV distant metastasis (n=12), where cfDNA mutation burden (CMB) levels correlated with TMB (p=0.019). This enabled earlier detection of stage IV disease recurrence compared to imaging (p&amp;lt;0.01), and captured tumor heterogeneity, and rising CMB levels prerecurrence clinical detection. An expanded 70-gene digital NGS panel was used to assess melanoma brain metastasis (MBM) in 26 preoperative MBM patients who had paired resected MBM tumors-cfDNA. Interestingly, tumor-identified MBM mutations were detected in the paired cfDNA at a concordance of 48%, 54%, and 58% at mutant allele frequency cut-offs of 0%, 0.5%, and 1%, respectively. Encouragingly, cfDNA-tumor SNV concordance was 88% in known melanoma driver genes (BRAF/NRAS). We then assessed a novel 1q21.3 CNA during melanoma progression in patients receiving checkpoint inhibitor immunotherapy (CII). Using a multiplex ddPCR assay targeting four 1q21.3 gene targets, we identified 77% (n=31) of patients at the time of progressive disease while on CII had 1q21.3 CNA in plasma whereby patients with stable disease, partial response, or disease free had low or no 1q21.3 CNA cfDNA. These results demonstrate the ability to use different multiplatform cfDNA biomarkers to monitor melanoma disease progression for recurrence and treatment response. The study demonstrates that cfDNA as mutation detection can be improved in melanoma using other genomic aberrations in monitoring immunotherapy in melanoma patients. Citation Format: David S. Hoon, Selena Y. Lin, Rebecca Gentry, Steve O’Day. Monitoring of melanoma progression utilizing multiplatform biomarkers of blood cell-free DNA [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr PR19.