Melanoma metastatic to the adrenal gland: An update on the role of adrenalectomy in multidisciplinary management.

BACKGROUND AND OBJECTIVES: Modern systemic therapy (immune checkpoint blockade [ICB], targeted therapy) has improved survival for patients with metastatic melanoma. The role of adrenal metastasectomy is not well characterized in this setting. METHODS: Consecutive patients treated with adrenalectomy 1/1/2007-1/1/2019 were retrospectively compared to patients treated with systemic therapy alone in the same time period. Overall survival and survival after adrenal metastasis were compared, prognostic factors associated with survival after adrenal metastasis development were evaluated. RESULTS: A total of 74 patients underwent adrenalectomy and were compared to 69 treated with systemic therapy alone. The most common indications for adrenalectomy were to render the patient disease-free in the setting of isolated adrenal metastasis (n = 32, 43.2%) or treatment of isolated progression in the setting of other stable/responding metastases (n = 32, 43.2%). Patients treated surgically had longer survival (116.9 vs. 11.0 months after adrenal metastasis diagnosis, p < 0.001). On multivariate analysis, receipt of ICB (hazard ratio [HR]: 0.62, 95% confidence interval [CI]: [0.40-0.95]) and selection for adrenalectomy (HR: 0.27, 95% CI: [0.17-0.42]) were the strongest factors associated with improved survival after adrenal metastasis diagnosis. CONCLUSIONS: Selective application of adrenal metastasectomy is associated with prolonged survival benefit and remains an important consideration in the multidisciplinary management of patients with metastatic melanoma.

Multiplatform Analysis of Intratumoral PTEN Heterogeneity in Melanoma.

Loss of protein expression of the tumor suppressor PTEN is associated with increased cancer aggressiveness, decreased tumor immune infiltration, and resistance to immune and targeted therapies in melanoma. We assessed a unique cohort of eight melanoma samples with focal loss of PTEN protein expression to understand the features and mechanisms of PTEN loss in this disease. We compared the PTEN-negative (PTEN[-]) areas to their adjacent PTEN-positive (PTEN[+]) areas using DNA sequencing, DNA methylation, RNA expression, digital spatial profiling, and immunohistochemical platforms. Variations or homozygous deletions of PTEN were identified in PTEN(-) areas that were not detected in the adjacent PTEN(+) areas in three cases (37.5%), but no clear genomic or DNA methylation basis for loss was identified in the remaining PTEN(-) samples. RNA expression data from two independent platforms identified a consistent increase in chromosome segregation gene expression in PTEN(-) versus adjacent PTEN(+) areas. Proteomic analysis showed a relative paucity of tumor-infiltrating lymphocytes in PTEN(-) versus adjacent PTEN(+) areas. The findings add to our understanding of potential molecular intratumoral heterogeneity in melanoma and the features associated with the loss of PTEN protein in this disease.

Concurrent intrathecal and intravenous nivolumab in leptomeningeal disease: phase 1 trial interim results.

There is a critical need for effective treatments for leptomeningeal disease (LMD). Here, we report the interim analysis results of an ongoing single-arm, first-in-human phase 1/1b study of concurrent intrathecal (IT) and intravenous (IV) nivolumab in patients with melanoma and LMD. The primary endpoints are determination of safety and the recommended IT nivolumab dose. The secondary endpoint is overall survival (OS). Patients are treated with IT nivolumab alone in cycle 1 and IV nivolumab is included in subsequent cycles. We treated 25 patients with metastatic melanoma using 5, 10, 20 and 50 mg of IT nivolumab. There were no dose-limiting toxicities at any dose level. The recommended IT dose of nivolumab is 50 mg (with IV nivolumab 240 mg) every 2 weeks. Median OS was 4.9 months, with 44% and 26% OS rates at 26 and 52 weeks, respectively. These initial results suggest that concurrent IT and IV nivolumab is safe and feasible with potential efficacy in patients with melanoma LMD, including in patients who had previously received anti-PD1 therapy. Accrual to the study continues, including in patients with lung cancer. ClinicalTrials.gov registration: NCT03025256 .

A Pilot Educational Intervention to Support Primary Care Provider Performance of Skin Cancer Examinations.

Educational interventions to support Primary Care Provider (PCP) performance of skin cancer examinations typically train PCPs to "triage and refer," an approach that may result in diagnostic delays in regions without appropriate access to dermatology care. To address the needs of PCPs and patients in regions without appropriate access to dermatology care, we developed a multi-faceted pilot intervention, including a curriculum and telementoring, designed to support PCP performance of skin cancer detection examinations. Our intervention offers two levels of proficiency: "triage and refer" and "diagnose and manage." The pilot intervention was conducted in collaboration with the Texas Tech University of Health Sciences Center El Paso, TX Family and Community Medicine Department (TTUHSC-El Paso). Participation in the intervention was voluntary, and 18-22 family medicine resident physicians completed the intervention tests. The participating family medicine resident physicians demonstrated statistically significant gains in knowledge and self-efficacy at the immediate post-intervention time points. Further adaption of the pilot intervention is needed to meet the needs of practicing PCPs. The pilot tests require further adaption and validation. Translating education delivery from live/synchronous to interactive virtual/asynchronous modules will support greater educational dissemination, and telementoring support is essential to address challenging cases encountered during patient care.

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

BACKGROUND: 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. METHODS: 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). RESULTS: A total of 791 MBM patients (PE, n = 332; CE, n = 459) were included in analysis. Median OS from MBM diagnosis was 10.3 months (95% CI, 8.9-12.4) and improved in the CE vs PE (14.4 vs 10.3 months, 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. CONCLUSIONS: OS and factors associated with OS have changed for MBM patients. This information can inform contemporary patient management and clinical investigations.

Obesity Is Associated with Altered Tumor Metabolism in Metastatic Melanoma.

PURPOSE: Overweight/obese (OW/OB) patients with metastatic melanoma unexpectedly have improved outcomes with immune checkpoint inhibitors (ICI) and BRAF-targeted therapies. The mechanism(s) underlying this association remain unclear, thus we assessed the integrated molecular, metabolic, and immune profile of tumors, as well as gut microbiome features, for associations with patient body mass index (BMI). EXPERIMENTAL DESIGN: Associations between BMI [normal (NL < 25) or OW/OB (BMI ≥ 25)] and tumor or microbiome characteristics were examined in specimens from 782 patients with metastatic melanoma across 7 cohorts. DNA associations were evaluated in The Cancer Genome Atlas cohort. RNA sequencing from 4 cohorts (n = 357) was batch corrected and gene set enrichment analysis (GSEA) by BMI category was performed. Metabolic profiling was conducted in a subset of patients (x = 36) by LC/MS, and in flow-sorted melanoma tumor cells (x = 37) and patient-derived melanoma cell lines (x = 17) using the Seahorse XF assay. Gut microbiome features were examined in an independent cohort (n = 371). RESULTS: DNA mutations and copy number variations were not associated with BMI. GSEA demonstrated that tumors from OW/OB patients were metabolically quiescent, with downregulation of oxidative phosphorylation and multiple other metabolic pathways. Direct metabolite analysis and functional metabolic profiling confirmed decreased central carbon metabolism in OW/OB metastatic melanoma tumors and patient-derived cell lines. The overall structure, diversity, and taxonomy of the fecal microbiome did not differ by BMI. CONCLUSIONS: These findings suggest that the host metabolic phenotype influences melanoma metabolism and provide insight into the improved outcomes observed in OW/OB patients with metastatic melanoma treated with ICIs and targeted therapies. See related commentary by Smalley, p. 5.

Musculoskeletal Injuries During U.S. Air Force Special Warfare Training Assessment and Selection, Fiscal Years 2019-2021.

From the inception of the Special Warfare Training Wing in fiscal year 2019 through 2021, 753 male, enlisted candidates attempted at least 1 Assessment and Selection and did not self-eliminate (i.e., quit). Candidates were on average 23 years of age. During candidates' first attempt, 356 (47.3%) individuals experienced a musculoskeletal (MSK) injury. Among the injuries, the most frequent type was nonspecific (n=334/356; 93.8%), and the most common anatomic region of injury was the lower extremity (n=255/356; 71.6%). When included in a multivariable model, older age, slower run times on initial fitness tests, and prior nonspecific injury were associated with both any injury and specifically lower extremity MSK injury.

Multi-modal molecular programs regulate melanoma cell state.

Melanoma cells display distinct intrinsic phenotypic states. Here, we seek to characterize the molecular regulation of these states using multi-omic analyses of whole exome, transcriptome, microRNA, long non-coding RNA and DNA methylation data together with reverse-phase protein array data on a panel of 68 highly annotated early passage melanoma cell lines. We demonstrate that clearly defined cancer cell intrinsic transcriptomic programs are maintained in melanoma cells ex vivo and remain highly conserved within melanoma tumors, are associated with distinct immune features within tumors, and differentially correlate with checkpoint inhibitor and adoptive T cell therapy efficacy. Through integrative analyses we demonstrate highly complex multi-omic regulation of melanoma cell intrinsic programs that provide key insights into the molecular maintenance of phenotypic states. These findings have implications for cancer biology and the identification of new therapeutic strategies. Further, these deeply characterized cell lines will serve as an invaluable resource for future research in the field.

Androgen receptor blockade promotes response to BRAF/MEK-targeted therapy.

Treatment with therapy targeting BRAF and MEK (BRAF/MEK) has revolutionized care in melanoma and other cancers; however, therapeutic resistance is common and innovative treatment strategies are needed1,2. Here we studied a group of patients with melanoma who were treated with neoadjuvant BRAF/MEK-targeted therapy ( NCT02231775 , n = 51) and observed significantly higher rates of major pathological response (MPR; ≤10% viable tumour at resection) and improved recurrence-free survival (RFS) in female versus male patients (MPR, 66% versus 14%, P = 0.001; RFS, 64% versus 32% at 2 years, P = 0.021). The findings were validated in several additional cohorts2-4 of patients with unresectable metastatic melanoma who were treated with BRAF- and/or MEK-targeted therapy (n = 664 patients in total), demonstrating improved progression-free survival and overall survival in female versus male patients in several of these studies. Studies in preclinical models demonstrated significantly impaired anti-tumour activity in male versus female mice after BRAF/MEK-targeted therapy (P = 0.006), with significantly higher expression of the androgen receptor in tumours of male and female BRAF/MEK-treated mice versus the control (P = 0.0006 and P = 0.0025). Pharmacological inhibition of androgen receptor signalling improved responses to BRAF/MEK-targeted therapy in male and female mice (P = 0.018 and P = 0.003), whereas induction of androgen receptor signalling (through testosterone administration) was associated with a significantly impaired response to BRAF/MEK-targeted therapy in male and female patients (P = 0.021 and P < 0.0001). Together, these results have important implications for therapy.

Economic and health care resource utilization burden of central nervous system metastases in patients with metastatic melanoma.

BACKGROUND: In patients with metastatic melanoma, central nervous system (CNS) involvement is associated with poor prognosis, increased costs, and higher health care resource utilization (HCRU); however, previous cost-estimate studies were conducted before widespread use of targeted therapies and immunotherapies. OBJECTIVE: To estimate costs and HCRU in patients with metastatic melanoma with and without CNS metastases in the current treatment era following introduction of targeted therapies and immunotherapies. METHODS: This real-world retrospective cohort study used data from the IQVIA PharMetrics Plus claims database to estimate and compare costs and HCRU in patients with metastatic melanoma by presence or absence of CNS metastases between January 2011 and June 2019. Patients with at least 2 melanoma claims, at least 2 metastatic claims, and continuous enrollment at least 6 months before and at least 1 month after first metastatic diagnosis were included. Mean per-patient-per-month (PPPM) costs are reported in 2019 US dollars. Analyses were also conducted by time period of first metastatic diagnosis: 2011-2014 (reflecting BRAF inhibitor monotherapy and anti-CTLA-4 therapy) and 2015-2019 (reflecting availability of BRAF and MEK inhibitor combinations and anti-PD-1/PD-L1 therapies). RESULTS: Of 4,078 patients, 1,253 (30.7%) had CNS metastases. Patients with CNS metastases were more likely to receive any treatment (89.1% vs 58.9%; P < 0.001), including systemic treatment (73.3% vs 55.4%; P < 0.001) and radiation (65.8% vs 11.8%; P < 0.001), and to have brain imaging any time after metastatic diagnosis (98.3% vs 67.2%; P < 0.001). In patients with CNS metastases, 40.0% had dexamethasone 4 mg within 30 days of CNS metastatic diagnosis. Patients with CNS metastases incurred higher total mean PPPM costs ($29,953 vs $14,996; P < 0.001). The largest contributors were total radiology ($2,351 vs $1,110), targeted therapies ($2,499 vs $638), and immunotherapies ($7,398 vs $5,036). HCRU and costs were higher in patients with vs without CNS metastases regardless of time period of first metastatic diagnosis. In patients with CNS metastases, use of any systemic treatment was increased in 2015-2019 vs 2011-2014 (81.2% vs 64.5%; P < 0.001), including chemotherapy (68.1% vs 50.0%; P < 0.001), immunotherapy (60.9% vs 30.1%; P < 0.001), and/or targeted therapies (32.7% vs 27.4%; P = 0.05). Mean total PPPM costs for patients with CNS metastases increased from $28,183 in 2011-2014 to $31,569 in 2015-2019 (P < 0.001); main drivers were immunotherapies and targeted therapies. CONCLUSIONS: CNS metastases occur frequently in patients with metastatic melanoma and are associated with significantly increased economic burden compared with patients without CNS metastases; the largest contributors to total costs in the current treatment era are radiology, targeted therapies, and immunotherapies. Brain imaging remains underused, and there is an opportunity to improve outcomes through early detection of CNS metastases, potentially reducing the high HCRU and costs associated with CNS metastases. DISCLOSURES: This study was funded by F. Hoffmann-La Roche Ltd. The sponsor was involved in the study design, data collection, data analysis, manuscript preparation, and publication decisions. Seetasith and Lee are employed by and report stock ownership in Genentech, Inc. Bartley and McKenna were employed by Genentech, Inc., at the time of this study and report stock ownership. Tawbi reports grants and personal fees from Genentech/Roche, Novartis, BMS, and Merck; grants from GSK and Celgene; and personal fees from Eisai, outside the submitted work. Kent, Burton, and Haydu have nothing to disclose. The results of this study were presented in part at the AMCP Nexus 2020 Virtual Meeting, October 19-23, 2020.

Clinical Models to Define Response and Survival With Anti-PD-1 Antibodies Alone or Combined With Ipilimumab in Metastatic Melanoma.

PURPOSE: Currently, there are no robust biomarkers that predict immunotherapy outcomes in metastatic melanoma. We sought to build multivariable predictive models for response and survival to anti-programmed cell death protein 1 (anti-PD-1) monotherapy or in combination with anticytotoxic T-cell lymphocyte-4 (ipilimumab [IPI]; anti-PD-1 ± IPI) by including routine clinical data available at the point of treatment initiation. METHODS: One thousand six hundred forty-four patients with metastatic melanoma treated with anti-PD-1 ± IPI at 16 centers from Australia, the United States, and Europe were included. Demographics, disease characteristics, and baseline blood parameters were analyzed. The end points of this study were objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). The final predictive models for ORR, PFS, and OS were determined through penalized regression methodology (least absolute shrinkage and selection operator method) to select the most significant predictors for all three outcomes (discovery cohort, N = 633). Each model was validated internally and externally in two independent cohorts (validation-1 [N = 419] and validation-2 [N = 592]) and nomograms were created. RESULTS: The final model for predicting ORR (area under the curve [AUC] = 0.71) in immunotherapy-treated patients included the following clinical parameters: Eastern Cooperative Oncology Group Performance Status, presence/absence of liver and lung metastases, serum lactate dehydrogenase, blood neutrophil-lymphocyte ratio, therapy (monotherapy/combination), and line of treatment. The final predictive models for PFS (AUC = 0.68) and OS (AUC = 0.77) included the same variables as those in the ORR model (except for presence/absence of lung metastases), and included presence/absence of brain metastases and blood hemoglobin. Nomogram calculators were developed from the clinical models to predict outcomes for patients with metastatic melanoma treated with anti-PD-1 ± IPI. CONCLUSION: Newly developed combinations of routinely collected baseline clinical factors predict the response and survival outcomes of patients with metastatic melanoma treated with immunotherapy and may serve as valuable tools for clinical decision making.

Treatment patterns and clinical outcomes for patients with melanoma and central nervous system metastases: A real-world study.

BACKGROUND: Patients with melanoma and central nervous system (CNS) metastases have poor survival outcomes. We investigated real-world treatment patterns and overall survival (OS) of patients with melanoma and CNS metastases. METHODS: A retrospective analysis utilizing a nationwide de-identified electronic health record-derived database was undertaken in patients diagnosed with advanced melanoma between January 2011 and September 2018. Patients with any visit ≤90 days of metastatic diagnosis and with confirmed CNS metastases were included. RESULTS: Of 3473 patients diagnosed with advanced melanoma, 791 patients with confirmed CNS metastases were identified and included in this analysis. Synchronous CNS metastasis (≤30 days of metastatic diagnosis) was associated with longer median OS than metachronous CNS metastasis (>30 days after metastatic diagnosis, 0.58 vs 0.42 years). Stereotactic radiosurgery (SRS) was the most common treatment (40.5%) alone or in combination with other local or systemic therapies, being more frequent in patients diagnosed in 2015+ versus 2011-2014 (44.1% vs 35.5%, respectively). The most common systemic treatment was immune checkpoint inhibitors (ICIs; 30.5%), predominantly anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4) alone (2011-2014) and anti-programmed death-1 alone or in combination with anti-CTLA-4 (2015+). Median OS was longest in SRS-treated patients (1.17 years) regardless of number of CNS metastases. Median OS for SRS-treated patients increased from 0.83 years (2011-2014) to 1.75 years (2015+). In multivariable analysis, the effect of SRS remained significant after adjustment for sex, race, intracranial and extracranial disease burden, and timing of CNS metastases. Interaction testing to examine potential synergy between SRS/whole-brain radiation therapy and ICIs found no significant interaction. CONCLUSIONS: Despite advances in treatment, patients with melanoma and CNS metastases have poor survival outcomes. Prevalence of SRS increased over time and was associated with improved outcomes.

Cutaneous adverse events in 155 patients with metastatic melanoma consecutively treated with anti-CTLA4 and anti-PD1 combination immunotherapy: Incidence, management, and clinical benefit.

BACKGROUND: In response to the increased use of combination checkpoint inhibitors (CPIs) and the resulting increased cutaneous adverse events (CAEs), this study reviewed patients with melanoma treated with combination CPIs to characterize CAE features and their clinical impact, correlation to adverse events in other organs, and correlation to tumor response. METHODS: Patients from the authors' institutional database who received at least 1 dose of ipilimumab in combination with either nivolumab or pembrolizumab between January 1, 2012, and December 31, 2017, for stage IV or unresectable stage III melanoma were identified. The time to next treatment (TTNT) was calculated from the start of CPI therapy to the start of the next treatment or death, and the development of CAEs was tested in a time-dependent Cox regression to identify associations with TTNT. RESULTS: Eighty-one patients (52.3%) experienced a total of 92 CAEs, including eczematous dermatitis (25.0%), morbilliform eruption (22.8%), vitiligo (12.0%), and pruritus without rash (8.7%). The median times to the onset and resolution of CAEs were 21 days (range, 0-341 days) and 50 days (range, 1-352 days), respectively. Most CAEs resolved after patients entered the CPI maintenance phase and treatment with oral antihistamines with or without topical steroids. CPI discontinuation occurred in 4 patients (2.6%) because of CAEs, in 49 (31.6%) because of other immune-related adverse events, and in 20 (12.9%) because of melanoma progression or death. For patients definitively treated with CPIs (n = 134; 86.5%), TTNT was significantly longer with CAEs than without CAEs (hazard ratio, 0.567; 95% CI, 0.331-0.972; P = .039). CONCLUSIONS: CAEs were mostly reversible and rarely required therapy discontinuation. The development of CAEs was associated with a longer TTNT, and this suggested a possible clinical benefit.

Chemotherapy after immune checkpoint inhibitor failure in metastatic melanoma: a retrospective multicentre analysis.

INTRODUCTION: Despite remarkably improved outcomes with immune checkpoint inhibition, many patients with metastatic melanoma will eventually require further therapy. Chemotherapy has limited activity when used first-line but can alter the tumour microenvironment and does improve efficacy when used in combination with immunotherapy in lung cancer. Whether chemotherapy after checkpoint inhibitor failure has relevant activity in patients with metastatic melanoma is unknown. METHODS: Patients with metastatic melanoma treated with chemotherapy after progression on immunotherapy with checkpoint inhibitors were identified retrospectively from 24 melanoma centres. Objective response rate (ORR), progression-free survival (PFS), overall survival (OS) and safety were examined. RESULTS: In total, 463 patients were treated between 2007 and 2017. Fifty-six per cent had received PD-1-based therapy before chemotherapy. Chemotherapy regimens included carboplatin + paclitaxel (32%), dacarbazine (25%), temozolomide (15%), taxanes (9%, nab-paclitaxel 4%), fotemustine (6%) and others (13%). Median duration of therapy was 7.9 weeks (0-108). Responses included 0.4% complete response (CR), 12% partial response (PR), 21% stable disease (SD) and 67% progressive disease (PD). Median PFS was 2.6 months (2.2, 3.0), and median PFS in responders was 8.7 months (6.3, 16.3), respectively. Twelve-month PFS was 12% (95% CI 2-15%). In patients who had received anti-PD-1 before chemotherapy, the ORR was 11%, and median PFS was 2.5 months (2.1, 2.8). The highest activity was achieved with single-agent taxanes (N = 40), with ORR 25% and median PFS 3.9 months (2.1, 6.2). Median OS from chemotherapy start was 7.1 months (6.5, 8.0). Subsequent treatment with checkpoint inhibitors achieved a response rate of 16% with a median PFS of 19.1 months (2.0-43.1 months). No unexpected toxicities were observed. CONCLUSION: Chemotherapy has a low response rate and short PFS in patients with metastatic melanoma who have failed checkpoint inhibitor therapy, although activity varied between regimens. Chemotherapy has a limited role in the management of metastatic melanoma.

Coenzyme A fuels T cell anti-tumor immunity.

Metabolic programming is intricately linked to the anti-tumor properties of T cells. To study the metabolic pathways associated with increased anti-tumor T cell function, we utilized a metabolomics approach to characterize three different CD8+ T cell subsets with varying degrees of anti-tumor activity in murine models, of which IL-22-producing Tc22 cells displayed the most robust anti-tumor activity. Tc22s demonstrated upregulation of the pantothenate/coenzyme A (CoA) pathway and a requirement for oxidative phosphorylation (OXPHOS) for differentiation. Exogenous administration of CoA reprogrammed T cells to increase OXPHOS and adopt the CD8+ Tc22 phenotype independent of polarizing conditions via the transcription factors HIF-1α and the aryl hydrocarbon receptor (AhR). In murine tumor models, treatment of mice with the CoA precursor pantothenate enhanced the efficacy of anti-PDL1 antibody therapy. In patients with melanoma, pre-treatment plasma pantothenic acid levels were positively correlated with the response to anti-PD1 therapy. Collectively, our data demonstrate that pantothenate and its metabolite CoA drive T cell polarization, bioenergetics, and anti-tumor immunity.

Dietary fiber and probiotics influence the gut microbiome and melanoma immunotherapy response.

Gut bacteria modulate the response to immune checkpoint blockade (ICB) treatment in cancer, but the effect of diet and supplements on this interaction is not well studied. We assessed fecal microbiota profiles, dietary habits, and commercially available probiotic supplement use in melanoma patients and performed parallel preclinical studies. Higher dietary fiber was associated with significantly improved progression-free survival in 128 patients on ICB, with the most pronounced benefit observed in patients with sufficient dietary fiber intake and no probiotic use. Findings were recapitulated in preclinical models, which demonstrated impaired treatment response to anti­programmed cell death 1 (anti­PD-1)­based therapy in mice receiving a low-fiber diet or probiotics, with a lower frequency of interferon-γ­positive cytotoxic T cells in the tumor microenvironment. Together, these data have clinical implications for patients receiving ICB for cancer.

Identification of MicroRNA-mRNA Networks in Melanoma and Their Association with PD-1 Checkpoint Blockade Outcomes.

Metastatic melanoma is a deadly malignancy with poor outcomes historically. Immuno-oncology (IO) agents, targeting immune checkpoint molecules such as cytotoxic T-lymphocyte associated protein-4 (CTLA-4) and programmed cell death-1 (PD-1), have revolutionized melanoma treatment and outcomes, achieving significant response rates and remarkable long-term survival. Despite these vast improvements, roughly half of melanoma patients do not achieve long-term clinical benefit from IO therapies and there is an urgent need to understand and mitigate mechanisms of resistance. MicroRNAs are key post-transcriptional regulators of gene expression that regulate many aspects of cancer biology, including immune evasion. We used network analysis to define two core microRNA-mRNA networks in melanoma tissues and cell lines corresponding to 'MITF-low' and 'Keratin' transcriptomic subsets of melanoma. We then evaluated expression of these core microRNAs in pre-PD-1-inhibitor-treated melanoma patients and observed that higher expression of miR-100-5p and miR-125b-5p were associated with significantly improved overall survival. These findings suggest that miR-100-5p and 125b-5p are potential markers of response to PD-1 inhibitors, and further evaluation of these microRNA-mRNA interactions may yield further insight into melanoma resistance to PD-1 inhibitors.