Automated Quantitative CD8+ Tumor-Infiltrating Lymphocytes and Tumor Mutation Burden as Independent Biomarkers in Melanoma Patients Receiving Front-Line Anti-PD-1 Immunotherapy

BACKGROUND

CD8+ tumor-infiltrating lymphocyte (TIL) predicts response to anti-PD-(L)1 therapy. However, there remains no standardized method to assess CD8+ TIL in melanoma, and developing a specific, cost-effective, reproducible, and clinically actionable biomarker to anti-PD-(L)1 remains elusive. We report on the development of automatic CD8+ TIL density quantification via whole slide image (WSI) analysis in advanced melanoma patients treated with front-line anti-PD-1 blockade, and correlation immunotherapy response.

METHODS

Seventy-eight patients treated with PD-1 inhibitors in the front-line setting between January 2015 and May 2023 at the University of Pittsburgh Cancer Institute were included. CD8+ TIL density was quantified using an image analysis algorithm on digitized WSI. Targeted next-generation sequencing (NGS) was performed to determine tumor mutation burden (TMB) in a subset of 62 patients. ROC curves were used to determine biomarker cutoffs and response to therapy. Correlation between CD8+ TIL density and TMB cutoffs and response to therapy was studied.

RESULTS

Higher CD8+ TIL density was significantly associated with improved response to front-line anti-PD-1 across all time points measured. CD8+ TIL density ≥222.9 cells/mm2 reliably segregated responders and non-responders to front-line anti-PD-1 therapy regardless of when response was measured. In a multivariate analysis, patients with CD8+ TIL density exceeding cutoff had significantly improved PFS with a trend toward improved OS. Similarly, increasing TMB was associated with improved response to anti-PD-1, and a cutoff of 14.70 Mut/Mb was associated with improved odds of response. The correlation between TMB and CD8+ TIL density was low, suggesting that each represented independent predictive biomarkers of response.

CONCLUSIONS

An automatic digital analysis algorithm provides a standardized method to quantify CD8+ TIL density, which predicts response to front-line anti-PD-1 therapy. CD8+ TIL density and TMB are independent predictors of response to anti-PD-1 blockade.

Matched three-dimensional organoids and two-dimensional cell lines of melanoma brain metastases mirror response to targeted molecular therapy

Purpose

Despite significant advances in the treatment paradigm for patients with metastatic melanoma, melanoma brain metastasis (MBM) continues to represent a significant treatment challenge. The study of MBM is limited, in part, by shortcomings in existing preclinical models. Surgically eXplanted Organoids (SXOs) are ex vivo, three-dimensional cultures prepared from primary tissue samples with minimal processing that recapitulate genotypic and phenotypic features of parent tumors and are grown without artificial extracellular scaffolding. We aimed to develop the first matched patient-derived SXO and cell line models of MBM to investigate responses to targeted therapy.

Methods

MBM SXOs were created by a novel protocol incorporating techniques for establishing glioma and cutaneous melanoma organoids. A BRAFV600K-mutant and BRAF-wildtype MBM sample were collected directly from the operating room for downstream experiments. Organoids were cultured in an optimized culture medium without an artificial extracellular scaffold. Concurrently, matched patient-derived cell lines were created. Drug screens were conducted to assess treatment response in SXOs and cell lines.

Results

Organoid growth was observed within 3-4 weeks, and MBM SXOs retained histological features of the parent tissue, including pleomorphic epithelioid cells with abundant cytoplasm, large nuclei, focal melanin accumulation, and strong SOX10 positivity. After sufficient growth, organoids could be manually parcellated to increase the number of replicates. Matched SXOs and cell lines demonstrated sensitivity to BRAF and MEK inhibitors.

Conclusion

Here, we describe the creation of a scaffold-free organoid model of MBM. Further study using SXOs may improve the translational relevance of preclinical studies and enable the study of the metastatic melanoma tumor microenvironment.

Immunotherapy combination approaches: mechanisms, biomarkers and clinical observations

The approval of the first immune checkpoint inhibitors provided a paradigm shift for the treatment of malignancies across a broad range of indications. Whereas initially, single-agent immune checkpoint inhibition was used, increasing numbers of patients are now treated with combination immune checkpoint blockade, where non-redundant mechanisms of action of the individual agents generally lead to higher response rates. Furthermore, immune checkpoint therapy has been combined with various other therapeutic modalities, including chemotherapy, radiotherapy and other immunotherapeutics such as vaccines, adoptive cellular therapies, cytokines and others, in an effort to maximize clinical efficacy. Currently, a large number of clinical trials test combination therapies with an immune checkpoint inhibitor as a backbone. However, proceeding without inclusion of broad, if initially exploratory, biomarker investigations may ultimately slow progress, as so far, few combinations have yielded clinical successes based on clinical data alone. Here, we present the rationale for combination therapies and discuss clinical data from clinical trials across the immuno-oncology spectrum. Moreover, we discuss the evolution of biomarker approaches and highlight the potential new directions that comprehensive biomarker studies can yield.

Dabrafenib plus trametinib versus anti-PD-1 monotherapy as adjuvant therapy in BRAF V600-mutant stage III melanoma after definitive surgery: a multicenter, retrospective cohort study

Background

Both dabrafenib/trametinib (D/T) and anti-PD-1 monotherapy (PD-1) are approved adjuvant therapies for patients with stage III BRAF V600-mutant melanoma. However, there is still a lack of head-to-head comparative data. We aimed to describe efficacy and toxicity outcomes for these two standard therapies across melanoma centers.

Methods

This multicenter, retrospective cohort study was conducted in 15 melanoma centers in Australia, China, Germany, Italy, Japan, UK, and US. We included adult patients with resected stage III BRAF V600-mutant melanoma who received either adjuvant D/T or PD-1 between Jul 2015 and Oct 2022. The primary endpoint was relapse-free survival (RFS). Secondary endpoints included overall survival (OS), recurrence pattern and toxicity.

Findings

We included 598 patients with stage III BRAF V600-mutant melanoma who received either adjuvant D/T (n = 393 [66%]) or PD-1 (n = 205 [34%]) post definitive surgery between Jul 2015 and Oct 2022. At a median follow-up of 33 months (IQR 21-43), the median RFS was 51.0 months (95% CI 41.0-not reached [NR]) in the D/T group, significantly longer than PD-1 (44.8 months [95% CI 28.5-NR]) (univariate: HR 0.66, 95% CI 0.50-0.87, P = 0.003; multivariate: HR 0.58, 95% CI 0.39-0.86, P = 0.007), with comparable OS with PD-1 (multivariate, HR 0.90, 95% CI 0.48-1.70, P = 0.75). Similar findings were observed using a restricted-mean-survival-time model. Among those who experienced recurrence, the proportion of distant metastases was higher in the D/T cohort. D/T had a higher incidence of treatment modification due to adverse events (AEs) than PD-1, but fewer persistent AEs.

Interpretation

In patients with stage III BRAF V600-mutant melanoma post definitive surgery, D/T yielded better RFS than PD-1, with higher transient but lower persistent toxicity, and comparable OS. D/T seems to provide a better outcome compared with PD-1, but a longer follow-up and ideally a large prospective trial are needed.

Funding

Dr. Xue Bai was supported by the Beijing Hospitals Authority Youth Programme (QMS20211101) for her efforts devoted to this study. Dr. Keith T. Flaherty was funded by Adelson Medical Research Foundation for the efforts devoted to this study.

Identification of tumor-intrinsic drivers of immune exclusion in acral melanoma

Acral melanoma (AM) has distinct characteristics as compared with cutaneous melanoma and exhibits poor response to immune checkpoint inhibitors (ICIs). Tumor-intrinsic mechanisms of immune exclusion have been identified in many cancers but less studied in AM. We characterized clinically annotated tumors from patients diagnosed with AM at our institution in correlation with ICI response using whole transcriptome RNAseq, whole exome sequencing, CD8 immunohistochemistry, and multispectral immunofluorescence imaging. A defined interferon-γ-associated T cell-inflamed gene signature was used to categorize tumors into non-T cell-inflamed and T cell-inflamed phenotypes. In combination with AM tumors from two published studies, we systematically assessed the immune landscape of AM and detected differential gene expression and pathway activation in a non-T cell-inflamed tumor microenvironment (TME). Two single-cell(sc) RNAseq AM cohorts and 11 bulk RNAseq cohorts of various tumor types were used for independent validation on pathways associated with lack of ICI response. In total, 892 specimens were included in this study. 72.5% of AM tumors showed low expression of the T cell-inflamed gene signature, with 23.9% of total tumors categorized as the non-T cell-inflamed phenotype. Patients of low CD3+CD8+PD1+ intratumoral T cell density showed poor prognosis. We identified 11 oncogenic pathways significantly upregulated in non-T cell-inflamed relative to T cell-inflamed TME shared across all three acral cohorts (MYC, HGF, MITF, VEGF, EGFR, SP1, ERBB2, TFEB, SREBF1, SOX2, and CCND1). scRNAseq analysis revealed that tumor cell-expressing pathway scores were significantly higher in low versus high T cell-infiltrated AM tumors. We further demonstrated that the 11 pathways were enriched in ICI non-responders compared with responders across cancers, including AM, cutaneous melanoma, triple-negative breast cancer, and non-small cell lung cancer. Pathway activation was associated with low expression of interferon stimulated genes, suggesting suppression of antigen presentation. Across the 11 pathways, fatty acid synthase and CXCL8 were unifying downstream target molecules suggesting potential nodes for therapeutic intervention. A unique set of pathways is associated with immune exclusion and ICI resistance in AM. These data may inform immunotherapy combinations for immediate clinical translation.

Identification of tumor-intrinsic drivers of immune exclusion in acral melanoma

Background

Acral melanoma (AM) has distinct characteristics as compared to cutaneous melanoma and exhibits poor response to immune checkpoint inhibitors (ICI). Tumor-intrinsic mechanisms of immune exclusion have been identified in many cancers but less studied in AM.

Methods

We characterized clinically annotated tumors from patients diagnosed with AM at our institution in correlation with ICI response using whole transcriptome RNAseq, whole exome sequencing, CD8 immunohistochemistry, and multispectral immunofluorescence imaging. A defined interferon-γ-associated T cell-inflamed gene signature was used to categorize tumors into non-T cell-inflamed and T cell-inflamed phenotypes. In combination with AM tumors from two published studies, we systematically assessed the immune landscape of AM and detected differential gene expression and pathway activation in a non-T cell-inflamed tumor microenvironment (TME). Two single-cell(sc) RNAseq AM cohorts and 11 bulk RNAseq cohorts of various tumor types were used for independent validation on pathways associated with lack of ICI response. In total, 892 specimens were included in this study.

Results

72.5% of AM tumors showed low expression of the T cell-inflamed gene signature, with 23.9% of total tumors categorized as the non-T cell-inflamed phenotype. Patients of low CD3 + CD8 + PD1 + intratumoral T cell density showed poor prognosis. We identified 11 oncogenic pathways significantly upregulated in non-T cell-inflamed relative to T cell-inflamed TME shared across all three acral cohorts (MYC, HGF, MITF, VEGF, EGFR, SP1, ERBB2, TFEB, SREBF1, SOX2, and CCND1). scRNAseq analysis revealed that tumor cell-expressing pathway scores were significantly higher in low vs high T cell-infiltrated AM tumors. We further demonstrated that the 11 pathways were enriched in ICI non-responders compared to responders across cancers, including acral melanoma, cutaneous melanoma, triple-negative breast cancer, and non-small cell lung cancer. Pathway activation was associated with low expression of interferon stimulated genes, suggesting suppression of antigen presentation. Across the 11 pathways, fatty acid synthase and CXCL8 were unifying downstream target molecules suggesting potential nodes for therapeutic intervention.

Conclusions

A unique set of pathways is associated with immune exclusion and ICI resistance in AM. These data may inform immunotherapy combinations for immediate clinical translation.

Expression of lymphoid structure-associated cytokine/chemokine gene transcripts in tumor and protein in serum are prognostic of melanoma patient outcomes

Background

Proinflammatory chemokines/cytokines support development and maturation of tertiary lymphoid structures (TLS) within the tumor microenvironment (TME). In the current study, we sought to investigate the prognostic value of TLS-associated chemokines/cytokines (TLS-kines) expression levels in melanoma patients by performing serum protein and tissue transcriptomic analyses, and to then correlate these data with patients clinicopathological and TME characteristics.

Methods

Levels of TLS-kines in patients' sera were quantitated using a custom Luminex Multiplex Assay. The Cancer Genomic Atlas melanoma cohort (TCGA-SKCM) and a Moffitt Melanoma cohort were used for tissue transcriptomic analyses. Associations between target analytes and survival outcomes, clinicopathological variables, and correlations between TLS-kines were statistically analyzed.

Results

Serum of 95 patients with melanoma were evaluated; 48 (50%) female, median age of 63, IQR 51-70 years. Serum levels of APRIL/TNFSF13 were positively correlated with levels of both CXCL10 and CXCL13. In multivariate analyses, high levels of serum APRIL/TNFSF13 were associated with improved event-free survival after adjusting for age and stage (HR = 0.64, 95% CI 0.43-0.95; p = 0.03). High expression of APRIL/TNFSF13 tumor transcripts was significantly associated with improved OS in TCGA-SKCM (HR = 0.69, 95% CI 0.52-0.93; p = 0.01) and in Moffitt Melanoma patients (HR = 0.51, 95% CI: 0.32-0.82; p = 0.006). Further incorporation of CXCL13 and CXCL10 tumor transcript levels in a 3-gene index revealed that high APRIL/CXCL10/CXCL13 expression was associated with improved OS in the TCGA SKCM cohort (HR = 0.42, 95% CI 0.19-0.94; p = 0.035). Melanoma differentially expressed genes positively associated with high APRIL/CXCL10/CXCL13 tumor expression were linked to tumor infiltration by a diverse array of proinflammatory immune cell types.

Conclusion

Serum protein and tumor transcript levels of APRIL/TNFSF13 are associated with improved survival outcomes. Patients exhibiting high coordinate expression of APRIL/CXCL10/CXCL13 transcripts in their tumors displayed superior OS. Further investigation of TLS-kine expression profiles related to clinical outcomes in larger cohort studies is warranted.

Metformin is associated with improved clinical outcomes in patients with melanoma: a retrospective, multi-institutional study

Background

Pre-clinical studies have shown that metformin reduces intratumoral hypoxia, improves T-cell function, and increases sensitivity to PD-1 blockade, and metformin exposure has been associated with improved clinical outcomes in various types of cancer. However, the impact of this drug in diabetic melanoma patients has not yet been fully elucidated.

Methods

We reviewed 4,790 diabetic patients with stage I-IV cutaneous melanoma treated at the UPMC-Hillman Cancer Center and Memorial Sloan Kettering Cancer Center between 1996-2020. The primary endpoints included recurrence rates, progression free survival (PFS), and overall survival (OS) with and without metformin exposure. Tabulated variables included BRAF mutational status, immunotherapy (IMT) by type, and incidence of brain metastases.

Results

The five-year incidence of recurrence in stage I/II patients was significantly reduced with metformin exposure (32.3% vs 47.7%, p=0.012). The five-year recurrence rate for stage III patients was also significantly reduced (58.3% vs 77.3%, p=0.013) in the metformin cohort. OS was numerically increased in nearly all stages exposed to metformin, though this did not reach statistical significance. The incidence of brain metastases was significantly lower in the metformin cohort (8.9% vs 14.6%, p=0.039).

Conclusion

This is the first study to demonstrate significantly improved clinical outcomes in diabetic melanoma patients exposed to metformin. Overall, these results provide further rationale for ongoing clinical trials studying the potential augmentation of checkpoint blockade with metformin in advanced melanoma.

Plasma glycoproteomic biomarkers identify metastatic melanoma patients with reduced clinical benefit from immune checkpoint inhibitor therapy

The clinical success of immune-checkpoint inhibitors (ICI) in both resected and metastatic melanoma has confirmed the validity of therapeutic strategies that boost the immune system to counteract cancer. However, half of patients with metastatic disease treated with even the most aggressive regimen do not derive durable clinical benefit. Thus, there is a critical need for predictive biomarkers that can identify individuals who are unlikely to benefit with high accuracy so that these patients may be spared the toxicity of treatment without the likely benefit of response. Ideally, such an assay would have a fast turnaround time and minimal invasiveness. Here, we utilize a novel platform that combines mass spectrometry with an artificial intelligence-based data processing engine to interrogate the blood glycoproteome in melanoma patients before receiving ICI therapy. We identify 143 biomarkers that demonstrate a difference in expression between the patients who died within six months of starting ICI treatment and those who remained progression-free for three years. We then develop a glycoproteomic classifier that predicts benefit of immunotherapy (HR=2.7; p=0.026) and achieves a significant separation of patients in an independent cohort (HR=5.6; p=0.027). To understand how circulating glycoproteins may affect efficacy of treatment, we analyze the differences in glycosylation structure and discover a fucosylation signature in patients with shorter overall survival (OS). We then develop a fucosylation-based model that effectively stratifies patients (HR=3.5; p=0.0066). Together, our data demonstrate the utility of plasma glycoproteomics for biomarker discovery and prediction of ICI benefit in patients with metastatic melanoma and suggest that protein fucosylation may be a determinant of anti-tumor immunity.

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.

Phase I trial of pembrolizumab plus vemurafenib and cobimetinib in patients with metastatic melanoma

Background

Preclinical and translational evidence suggest BRAF/MEK inhibitors modulate the tumor microenvironment (TME), providing rationale for combination with immunotherapy.

Methods

This investigator-initiated, phase I trial evaluated pembrolizumab, vemurafenib, and cobimetinib in patients with untreated, BRAFV600E/K mutant advanced melanoma. The first 4 patients received vemurafenib with pembrolizumab, and the next 5 patients received vemurafenib and cobimetinib with pembrolizumab. Primary endpoints: safety and maximum tolerated dose of the triplet.

Secondary endpoints

objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and quality of life (QoL). The trial was closed after enrollment of 9 (planned 30) patients due to dose-limiting toxicity (DLT). Study NCT02818023 was approved by the IRB, and all patients provided informed consent.

Results

Patients received a median of 6 cycles of therapy. 8 of 9 experienced drug-related grade 3/4 AEs. DLTs included dermatitis (n=8), hepatitis (n=1), QTc prolongation (n=1), and arthralgias (n=1 each). QoL assessments identified a clinically significant decrease in self assessed QoL at 1 year compared to baseline (0.38 v 0.43). Median PFS was 20.7 months and median OS was 23.8 months for vemurafenib with pembrolizumab. Median PFS and OS were not reached for patients receiving triple therapy. ORR in the overall cohort was 78% (7/9). 2 patients experienced a complete response, 5 had a partial response, 1 had stable disease, and 1 had progressive disease. 4 patients had ongoing responses at data analysis. Peripheral blood flow cytometry identified significantly decreased PD1 expression on CD4+ T-cells at 3 and 9 weeks compared to baseline, not corresponding to clinical response.

Conclusions

Triple therapy with vemurafenib, cobimetinib and pembrolizumab is associated with high response rates but significant adverse events, leading to early study closure.

Phase II study of nivolumab (nivo) with relatlimab (rela) in patients (pts) with first-line advanced melanoma: Early on-treatment major pathologic response on biopsy

9514

Background: A phase II study of nivo and rela was designed to evaluate the antitumor activity and mechanism of this combination and components for first-line treatment of pts with advanced melanoma. Pts received lead-in treatment with 1 cycle of nivo (480mg IV q4wk), rela (160mg IV q4wk), or nivo-rela followed by combination therapy. We assessed the effect of each lead-in treatment on immune-related pathological response (irPR) at 4-wk biopsy to develop early biomarkers of antitumor response. Methods: Core biopsy of an index lesion was performed at baseline and after 4 wk on-treatment. Immune characteristics of pathological response were assessed on H&E sections, including presence of tumor-infiltrating lymphocytes (TIL), neovascularization, proliferative fibrosis, plasma cells, and lymphoid aggregates. irPR score was calculated as described by Stein JE et al Ann Oncol 2019, from 0 (no irPR features) to 3 (major pathologic response on biopsy [MPRbx], ≤10% residual viable tumor). We assessed the association between irPR and radiological response (RECIST v1.1) at 4-wk evaluations. Results: The current cohort includes 22 pts, median age = 67, male = 13. Pts were randomized to nivo = 7, rela = 7, and nivo-rela = 8 lead-in groups. Two pts had no irPR evaluation due to early progression and unscorable tumor. Among 20 evaluable pts, proliferative fibrosis, neovascularization, plasma cells, brisk TIL, and lymphoid aggregates were identified in 50%, 35%, 26.3%, 25%, and 5% of cases, respectively. Lead-in nivo (n = 2/6), rela (n = 0/6), and nivo-rela (n = 3/8) resulted in irPR = 3 in 25% of pts. Radiological response was identified as partial response (PR) = 1/22 (4.5%), stable disease (SD) = 12/22 (54.5%), and progressive disease (PD) = 9/22 (41%). Among pts with PD, 44% received rela-, 33% nivo-, and 22% nivo-rela- lead-in. Pts with irPR score = 3 had radiological PR = 1, SD = 3, and PD = 1 at 4wks. No association was found between MPRbx and radiological response at 4 wks. Conclusions: Four-wk MPRbx may serve as an early biomarker of treatment response in advanced melanoma. Lead-in treatment resulted in MPRbx of 25% and was greatest with nivo-rela lead-in. Correlations between 4 wk MPRbx and later radiological responses, survival and other endpoints will be made at completion of trial accrual. Clinical trial information: NCT03743766. [Table: see text]

Immune-Related Adverse Events in PD-1 Treated Melanoma and Impact Upon Anti-Tumor Efficacy: A Real World Analysis

Background

Anti-PD-1 immune checkpoint inhibitor (ICI) therapy has revolutionized the treatment of melanoma by producing durable long-term responses in a subset of patients. ICI-treated patients develop unique toxicities - immune related adverse events (irAEs) – that arise from unrestrained immune activation. The link between irAE development and clinical outcome in melanoma and other cancers is inconsistent; and little data exists on the occurrence of multiple irAEs. We sought to characterize development of single and multiple irAEs, and association of irAE(s) development with clinical variables and impact upon outcomes in advanced melanoma patients treated with anti-PD-1 ICIs.

Methods

We conducted a retrospective study of 190 patients with metastatic melanoma treated with single-agent anti-PD-1 ICI therapy between June 2014 and August 2020 at a large integrated network cancer center identified through retrospective review of pharmacy records. irAEs were graded based on the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0.

Results

190 patients were evaluated of whom 114 patients (60.0%) experienced ≥1 irAE, including 30 (15.8%) with grade 3/4 irAEs. The occurrence of any irAE was strongly associated with the development of investigator-assessed response to anti-PD-1 therapy (p < 0.0001); whether evaluated by current (p=0.0082) or best (p=0.0001) response. In patients with ≥2 irAEs, distinct patterns were observed. Median progression-free survival (PFS) and overall survival (OS) were greater in those with any irAE compared to those without (PFS, 28 months vs. 5 months, p < 0.0001; OS, not reached vs. 9 months, p < 0.0001). Development of ≥2 irAEs had a trend towards improved PFS and OS compared to those who developed a single irAE, although this did not reach statistical significance (p=0.2555, PFS; p=0.0583, OS). Obesity but not age or gender was distinctly associated with irAE development.

Conclusions

In this study, we demonstrated that irAE occurrence was significantly associated with response to anti-PD-1 therapy and improved PFS/OS. Those who developed multiple irAEs had a trend towards improved PFS and OS compared to those who developed only a single irAE. Increased BMI but neither age nor gender were associated with irAE development. Distinct patterns of irAEs observed suggest shared etiopathogenetic mechanisms.

Abstract LB062: Efficacy of Responder-derived Fecal Microbiota Transplant (R-FMT) and Pembrolizumab in Anti-PD-1 Refractory Patients with Advanced Melanoma

Background: Monoclonal antibodies (mAb) targeting the programmed cell death protein 1 (PD-1) receptor provide durable long-term benefit in a subset of patients (pts) with advanced melanoma with response rates of 35-42% and 4-year progression-free survival (PFS) rate of 27%. Separately, the composition of the gut microbiota has been shown to correlate with anti-PD-1 efficacy in human cancer pts with melanoma, renal cell cancer and non-small cell lung cancer (NSCLC) although the precise organisms differ considerably across various studies. In preclinical models, responder-derived fecal microbiome and microbiome consortia produce anti-tumor responses. The effect of microbiome modulation in pts with anti-PD-1 refractory melanoma has not been evaluated. Methods: To evaluate whether primary resistance to anti-PD-1 immunotherapy could be overcome by intestinal microbiome modulation, we designed and conducted a phase II study (NCT03341143). We enrolled pts with primary refractory metastatic melanoma with best response of short-term stable disease (≤6 months) or progressive disease (PD) to prior anti-PD-1 based immunotherapy. Pts received single-administration of responder-derived fecal microbiota transplantation (R-FMT) together with pembrolizumab. Candidate donors were pts with advanced melanoma treated with anti-PD-1 immunotherapy with durable partial or complete response (PR, CR). Pembrolizumab was continued till intolerable toxicity or disease progression. Safety and clinical activity (based on RECIST v1.1) were main objectives; while progression-free survival (PFS) was a key secondary endpoint. Results: As of December 1, 2020, 16 pts with primary refractory melanoma were enrolled, of whom 15 were evaluable. LDH was elevated in 14/15 pts; and the median number of prior therapies was 2. Recipient pts were seromatched to receive a single R-FMT from one of eight candidate donors (5 CR; 3 PR; median PFS 58 months, range 43-70). R-FMT was administered via colonoscopy after bowel preparation with no use of antibiotics. Pembrolizumab was administered IV per label. R-FMT/pembrolizumab was well-tolerated, with no unusual toxicity signals. R-FMT induced rapid and durable microbiota perturbation in most pts; while 6 of 15 evaluable pts had evidence of clinical benefit. Response to R-FMT/pembrolizumab was associated with an increased abundance of taxa previously shown to be associated with response to anti-PD-1, increased CD8+ T cell activation, and decreased frequency of IL-8 expressing myeloid cells. Responders had distinct proteomic and metabolomic signatures, and transkingdom network analyses confirmed that the gut microbiome regulated these changes. Conclusions: In pts with anti-PD-1 primary refractory melanoma, R-FMT/pembrolizumab changed the gut microbiome and reprogrammed the tumor microenvironment to overcome resistance to anti-PD-1 immunotherapy. Response was associated with CD8 T cell induction and reduction of IL-8 expressing myeloid cells.

Citation Format: Diwakar Davar, Amiran Dzutsev, John A. McCulloch, Richard R. Rodrigues, Joe-Marc Chauvin, Robert M. Morrison, Richelle N. Deblasio, Carmine Menna, Quanquan Ding, Ornella Pagliano, Bochra Zidi, Shuowen Zhang, Jonathan H. Badger, Marie Vetizou, Alicia M. Cole, Miriam R. Fernandes, Stephanie Prescott, Raquel G. Costa, Ascharya K. Balaji, Andrey Morgun, Ivan Vujkovic-Cvijin, Hong Wang, Amir A. Borhani, Marc B. Schwartz, Howard M. Dubner, Scarlett J. Ernst, Amy Rose, Yana G. Najjar, Yasmine Belkaid, John M. Kirkwood, Giorgio Trinchieri, Hassane M. Zarour. Efficacy of Responder-derived Fecal Microbiota Transplant (R-FMT) and Pembrolizumab in Anti-PD-1 Refractory Patients with Advanced Melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB062.

Search for effective treatments in patients with advanced refractory melanoma continues: can novel intratumoral therapies deliver?

Most patients with advanced melanoma ultimately fail immune checkpoint inhibitor (ICI) therapy because of primary or acquired resistance. There remains a critical unmet need for new therapies that function via alternative immune activation mechanisms to safely trigger an antitumor immune response in patients with ICI-refractory disease. This commentary discusses the recent failures and hope for novel intratumoral therapies under development in the advanced refractory melanoma setting, outlining key mechanistic differences that may be critical to yielding success in this difficult-to-treat population.

A phase I trial of pembrolizumab plus vemurafenib and cobimetinib in patients with advanced melanoma

e21506

Background: Management of patients (pts) with advanced melanoma includes anti-PD1 with or without anti-CTLA4, and for pts with a BRAF mutation, the additional option of targeted therapy. Preclinical and translational evidence suggest BRAF/MEK inhibitors (i) modulate the tumor microenvironment, providing rationale for combination with immune checkpoint inhibitors. Phase 3 IMspire data reported improved progression-free survival (PFS) with triplet therapy (atezolizumab/vemurafenib/cobimetinib), yielding regulatory approval. However, 79% of pts experienced grade 3/4 adverse events (AE) in the triplet arm. Methods: This is an investigator-initiated, phase I trial of pembrolizumab (pembro) plus vemurafenib (vem) and cobimetinib (cobi) for pts with advanced melanoma in the first line setting. The first 4 pts received vem/pembro. The protocol was subsequently amended, and the next 5 pts received vem/cobi/pembro. Vem/cobi had an escalating dosing regimen. Pembro was 200 mg q3 weeks. Primary endpoints: safety and maximum tolerated dose of vem/cobi when administered with pembro. Secondary endpoints: overall response rate (ORR), PFS, overall survival (OS), and quality of life (QoL). We planned to accrue 30 pts; however, the trial was closed after enrollment of 9 pts due to dose-limiting toxicity (DLT). This study NCT02818023 was approved by the IRB, and all pts provided informed consent. Results: Pts received a median of 6 cycles of triplet therapy. 8 of 9 pts experienced drug-related grade 3/4 AEs, most commonly dermatitis (89%). In the vem/pembro group, DLTs included hepatitis (n = 1), dermatitis (n = 3), and arthralgias (n = 1). In the vem/cobi/pembro group, DLTs included dermatitis (n = 5), QTc prolongation (n = 1), and arthralgias (n = 1). QoL assessments identified a clinically significant decrease in average health utility at 1 year compared to baseline (0.38 v 0.43). Median PFS was 20.7 months and median OS was 23.8 months for vem/pembro, and neither was reached for vem/cobi/pembro. Overall, 4 pts had ongoing responses at the time of data analysis. 2 pts experienced a complete response, 5 had a partial response, 1 had stable disease, and 1 had progressive disease at first restaging. Peripheral blood flow cytometry identified significantly decreased PD1 expression on CD4+ T-cells at 3 and 9 weeks compared to baseline. This did not correspond to clinical response. PD-L1 testing was also performed on 6 paired tumor samples, and no significant association was identified between PD-L1 expression and clinical outcomes. Conclusions: Despite preclinical and translational evidence for tumor immunomodulation with BRAF/MEKi and improved PFS noted in IMspire150, toxicity incurred with the triplet is challenging from a practical standpoint. Our study highlights clinical efficacy of the combination and adds additional toxicity data for triplet therapy, with 8 of 9 pts experiencing at least a grade 3 AE. Clinical trial information: NCT02818023.

A post-COVID survey of current and future parents among faculty, trainees, and research staff at an NCI-designated cancer center

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Background: Challenges for women in science and academic medicine have been well documented, which include gender disparities related to parental and domestic responsibilities that interfere with work or career opportunities. We aimed to evaluate the experiences and working environment at an NCI-designated Cancer Center for current and future parents in the post-COVID era. We hypothesized there would be differences in the experiences of parents between men and women, and between trainees, faculty, and staff. Methods: A 61-question online survey for current and future parents was developed by the Women’s Task Force of the Hillman Cancer Center (HCC) in Pittsburgh, Pennsylvania. Questions focused on perceived attitudes towards parents, the supportive nature of the working environment for parents, experiences with breastfeeding as a working parent, and childcare responsibilities pre- and post-COVID. The survey was sent to 562 scientific faculty, physicians, trainees, and research staff at HCC. Comparisons between groups of interest were performed using a chi-square test. Results: There were 214 respondents (38% response rate) with even representation: 38% were faculty, 27% were trainees, and 35% were research staff; 59% were female. 6% of respondents reported being “discouraged or excluded from participating in specific activities due to having or planning children”, and 24% felt “moderately supported” as a parent at work. Regarding breastfeeding, 58% reported that the decision to breastfeed was moderately impacted by returning to work, and of the women who were currently or recently breastfeeding, 42% reported that there were not enough lactation rooms in their building. Other questions in the survey aimed to evaluate what further support would be helpful for parents. 40% reported that on-site childcare would help better support them as a parent, especially because 47% documented that finding childcare was difficult and 53% documented that they looked at ≥4 daycares or nannies. Further, 49% reported that they did not know where to look for resources in finding childcare. Pre-COVID, 32% reported spending 2-3 hours a day on childcare and/or home responsibilities; post-COVID, 55% reported spending ≥4 hours a day. These effects were more pronounced in women compared to men (p < 0.05). Pre-COVID, 40% reported that they were unable to participate in work events due to childcare responsibilities, which increased to 54% post-COVID, and was most pronounced in faculty and trainees compared to staff (p < 0.05). Conclusions: Our survey describes some of the universal challenges of working parents in Oncology, which have been exacerbated by COVID. The impact of COVID was more pronounced in women. Further studies are needed for systematic interventions or policies that improve support for working parents, including unified resources and working groups for current and expecting parents.

Impact of the COVID-19 pandemic on staging at presentation of patients with invasive melanoma

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Background: The COVID-19 pandemic has impacted cancer care beyond the direct implications of viral infection. Delays in presentation and diagnosis may lead to more advanced disease and worse patient outcomes. We evaluated the impact of the pandemic on patients (pts) with melanoma (mel). Methods: A single-institution, retrospective comparison of pts with newly diagnosed invasive mel or metastatic recurrence prior to (pre-cohort, n = 246) and after (post-cohort, n = 246) declaration of the COVID-19 pandemic on March 11, 2020. 492 pts were evaluated between March 1, 2019 and January 12, 2021. Key variables collected included demographics, pathology, stage at diagnosis, surgical management, receipt of adjuvant or systemic therapy, and follow up. Categorical variables were compared using the two-sided Fisher’s exact test, continuous variables were compared using the two-sided Wilcoxon rank sum test, and survival endpoints were evaluated with the Kaplan-Meier method. This study was exempt from review by the IRB. Results: 200 (81.3%) pts presented with early-stage disease and 46 (18.7%) pts presented with metastatic disease in the post-cohort, compared to 209 (85%) and 37 (15%) pts in the pre-cohort, respectively. In the post-cohort there was a significant decrease in stage I pts (28.5% vs 40.7%, p = 0.006), a significant increase in stage III pts (30.5% vs 21.1%, p = 0.023), and a significant increase in pts with metastatic recurrence (7.7% vs 3.3%, p = 0.046) compared to the pre-cohort. There was also a significant increase in pts with brain metastases (BM) in the post-cohort (6.5% vs 1.6%, p = 0.010). For pts with early-stage disease, there was a significant increase in median Breslow depth (2.0 vs 1.4 mm, p = 0.047) and mitotic rate > 1 (78.1% vs 66%, p = 0.008) in the post-cohort. There were trends toward increased ulceration, lymphovascular/perineural invasion, and microsatellite presence. Pts receiving adjuvant therapy in the post-cohort were significantly more likely to receive oral targeted therapy (37.6% vs 27.5%) compared to IV immunotherapy (62.4% vs 72.5%), p = 0.034, perhaps reflecting an attempt to minimize in-person visits. There was not a significant difference between the 2 groups in the type of systemic therapy administered in the metastatic setting. Median progression-free and overall survival were not reached due to a limited number of events in each arm. Conclusions: There was a significant decrease in pts with stage I mel along with a significant increase in pts with stage III mel, metastatic recurrence, and BMs presenting to our institution during the pandemic. Findings are likely related to delays from both the patient (to avoid interaction with the healthcare system - including primary care, dermatology, and oncology) and from the system itself, with some clinics potentially evaluating pts in a limited capacity. These data reaffirm the importance of early detection and evaluation of melanoma.

Neoadjuvant Pembrolizumab and High-Dose IFNα-2b in Resectable Regionally Advanced Melanoma

PURPOSE

Neoadjuvant immunotherapy may improve the clinical outcome of regionally advanced operable melanoma and allows for rapid clinical and pathologic assessment of response. We examined neoadjuvant pembrolizumab and high-dose IFNα-2b (HDI) therapy in patients with resectable advanced melanoma.

PATIENTS AND METHODS

Patients with resectable stage III/IV melanoma were treated with concurrent pembrolizumab 200 mg i.v. every 3 weeks and HDI 20 MU/m²/day i.v., 5 days per week for 4 weeks, then 10 MU/m²/day subcutaneously 3 days per week for 2 weeks. Definitive surgery followed, as did adjuvant combination immunotherapy, completing a year of treatment. Primary endpoint was safety of the combination. Secondary endpoints included overall response rate (ORR), pathologic complete response (pCR), recurrence-free survival (RFS), and overall survival (OS). Blood samples for correlative studies were collected throughout. Tumor tissue was assessed by IHC and flow cytometry at baseline and at surgery.

RESULTS

A total of 31 patients were enrolled, and 30 were evaluable. At data cutoff (October 2, 2019), median follow-up for OS was 37.87 months (range, 33.2-43.47). Median OS and RFS were not reached. Radiographic ORR was 73.3% [95% confidence interval (CI): 55.5-85.8], with a 43% (95% CI: 27.3-60.1) pCR rate. None of the patients with a pCR have had a recurrence. HDI and pembrolizumab were discontinued in 73% and 43% of patients, respectively. Correlative analyses suggested that intratumoral PD-1/PD-L1 interaction and HLA-DR expression are associated with pCR (P = 0.002 and P = 0.008, respectively).

CONCLUSIONS

Neoadjuvant concurrent HDI and pembrolizumab demonstrated promising clinical activity despite high rates of treatment discontinuation. pCR is a prognostic indicator.See related commentary by Menzies et al., p. 4133.

Fecal microbiota transplant overcomes resistance to anti-PD-1 therapy in melanoma patients

Anti-programmed cell death protein 1 (PD-1) therapy provides long-term clinical benefits to patients with advanced melanoma. The composition of the gut microbiota correlates with anti-PD-1 efficacy in preclinical models and cancer patients. To investigate whether resistance to anti-PD-1 can be overcome by changing the gut microbiota, this clinical trial evaluated the safety and efficacy of responder-derived fecal microbiota transplantation (FMT) together with anti-PD-1 in patients with PD-1-refractory melanoma. This combination was well tolerated, provided clinical benefit in 6 of 15 patients, and induced rapid and durable microbiota perturbation. Responders exhibited increased abundance of taxa that were previously shown to be associated with response to anti-PD-1, increased CD8⁺ T cell activation, and decreased frequency of interleukin-8-expressing myeloid cells. Responders had distinct proteomic and metabolomic signatures, and transkingdom network analyses confirmed that the gut microbiome regulated these changes. Collectively, our findings show that FMT and anti-PD-1 changed the gut microbiome and reprogrammed the tumor microenvironment to overcome resistance to anti-PD-1 in a subset of PD-1 advanced melanoma.

Ipilimumab plus nivolumab for patients with metastatic uveal melanoma: a multicenter, retrospective study

BACKGROUND

Uveal melanoma (UM) is the most common intraocular malignancy in adults. In contrast to cutaneous melanoma (CM), there is no standard therapy, and the efficacy and safety of dual checkpoint blockade with nivolumab and ipilimumab is not well defined.

METHODS

We conducted a retrospective analysis of patients with metastatic UM (mUM) who received treatment with ipilimumab plus nivolumab across 14 academic medical centers. Toxicity was graded using National Cancer Institute Common Terminology Criteria for Adverse Events V.5.0. Progression-free survival (PFS) and overall survival (OS) were calculated using Kaplan-Meier methodology.

RESULTS

89 eligible patients were identified. 45% had received prior therapy, which included liver directed therapy (29%), immunotherapy (21%), targeted therapy (10%) and radiation (16%). Patients received a median 3 cycles of ipilimumab plus nivolumab. The median follow-up time was 9.2 months. Overall response rate was 11.6%. One patient achieved complete response (1%), 9 patients had partial response (10%), 21 patients had stable disease (24%) and 55 patients had progressive disease (62%). Median OS from treatment initiation was 15 months and median PFS was 2.7 months. Overall, 82 (92%) of patients discontinued treatment, 34 due to toxicity and 27 due to progressive disease. Common immune-related adverse events were colitis/diarrhea (32%), fatigue (23%), rash (21%) and transaminitis (21%).

CONCLUSIONS

Dual checkpoint inhibition yielded higher response rates than previous reports of single-agent immunotherapy in patients with mUM, but the efficacy is lower than in metastatic CM. The median OS of 15 months suggests that the rate of clinical benefit may be larger than the modest response rate.

Adjuvant therapy versus watch-and-wait post surgery for stage III melanoma: a multicountry retrospective chart review

AIM

To describe treatment patterns among patients with stage III melanoma who underwent surgical excision in years 2011-2016, and assess outcomes among patients who subsequently received systemic adjuvant therapy versus watch-and-wait.

METHODS

Chart review of 380 patients from 17 melanoma centers in North America, South America and Europe.

RESULTS

Of 129 (34%) patients treated with adjuvant therapy, 85% received interferon α-2b and 56% discontinued treatment (mostly due to adverse events). Relapse-free survival was significantly longer for patients treated with adjuvant therapy versus watch-and-wait (hazard ratio = 0.63; p < 0.05). There was considerable heterogeneity in adjuvant treatment schedules and doses. Similar results were found in patients who received interferon-based adjuvant therapy.

CONCLUSION

Adjuvant therapies with better safety/efficacy profiles will improve clinical outcomes in patients with stage III melanoma.

An updated analysis of 4 randomized ECOG trials of high-dose interferon in the adjuvant treatment of melanoma

BACKGROUND

The pivotal E1684, E1690, E1694, and E2696 trials of adjuvant high-dose interferon-α (HDI) enrolled nearly 2000 patients, and established HDI as the standard of care in adjuvant therapy for patients with resected high-risk melanoma. Herein, the authors present an updated analysis of these 4 trials.

METHODS

Survival and disease status were updated in September 2016. These data represent a median follow-up of 17.9 years for the E1684 trial, 12.2 years for the E1690 trial, 16.0 years for the E1694 trial, and 16.5 years for the E2696 trial.

RESULTS

The current analysis confirmed the benefit to recurrence-free survival (RFS) of HDI in the E1684 trial at a median follow-up of 17.9 years. The RFS benefit in the E1694 trial remained evident at a median follow-up of 16 years. Furthermore, the results of the current study confirmed the RFS benefit of adjuvant HDI compared with observation in a pooled analysis of the E1684 and E1690 trials. No overall survival benefit was apparent in this pooled analysis. Updated results for the E1690 and E2696 trials did not differ from those previously reported. In addition, to the authors' knowledge, the current study is the first to report a significant difference in melanoma-specific survival (MSS) between patients treated with HDI compared with the ganglioside GM2/keyhole limpet hemocyanin (GMK) vaccine in the E1694 trial.

CONCLUSIONS

In patients with resected high-risk melanoma, adjuvant HDI demonstrated improved RFS in the E1684 and E1694 trials, and improved MSS in a pooled analysis of HDI in the E1694 trial. To the authors' knowledge, these findings represent the most mature level of evidence for the benefit of HDI with respect to RFS and MSS. HDI is the only approved adjuvant treatment for which there are data available in patients with resected stage IIB/IIC melanoma, and remains a reasonable treatment option in this population.

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

In February 2018, the Melanoma Research Foundation and the Moffitt Cancer Center hosted the Second Summit on Melanoma Central Nervous System (CNS) Metastases in Tampa, Florida. In this white paper, we outline the current status of basic science, translational, and clinical research into melanoma brain metastasis development and therapeutic management. We further outline the important challenges that remain for the field and the critical barriers that need to be overcome for continued progress to be made in this clinically difficult area.

Tumor cell oxidative metabolism as a barrier to PD-1 blockade immunotherapy in melanoma

The tumor microenvironment presents physical, immunologic, and metabolic barriers to durable immunotherapy responses. We have recently described roles for both T cell metabolic insufficiency as well as tumor hypoxia as inhibitory mechanisms that prevent T cell activity in murine tumors, but whether intratumoral T cell activity or response to immunotherapy varies between patients as a function of distinct metabolic profiles in tumor cells remains unclear. Here, we show that metabolic derangement can vary widely in both degree and type in patient-derived cell lines and in ex vivo analysis of patient samples, such that some cells demonstrate solely deregulated oxidative or glycolytic metabolism. Further, deregulated oxidative, but not glycolytic, metabolism was associated with increased generation of hypoxia upon implantation into immunodeficient animals. Generation of murine single-cell melanoma cell lines that lacked either oxidative or glycolytic metabolism showed that elevated tumor oxygen consumption was associated with increased T cell exhaustion and decreased immune activity. Moreover, melanoma lines lacking oxidative metabolism were solely responsive to anti-PD-1 therapy among those tested. Prospective analysis of patient sample immunotherapy revealed that oxidative, but not glycolytic, metabolism was associated with progression on PD-1 blockade. Our data highlight a role for oxygen as a crucial metabolite required for the tumor-infiltrating T cells to differentiate appropriately upon PD-1 blockade, and suggest that tumor oxidative metabolism may be a target to improve immunotherapeutic response.

Melanoma antigen-specific effector T cell cytokine secretion patterns in patients treated with ipilimumab

Background

In a previously reported study, patients with regionally advanced melanoma were treated with neoadjuvant ipilimumab (ipi) (Tarhini in PLoS ONE 9(2): e87705, 3). Significant changes in circulating myeloid derived suppressor cells (MDSC), regulatory T cells (Treg) and peptide specific type I CD4⁺ and CD8⁺ T cells were noted at week 6 that correlated with clinical outcome. Characterization of antigen-specific effector T cell secreted cytokines may shed insights into ipi associated T cell activation and function.

Methods

Patients were treated with neoadjuvant ipi (10 mg/kg every 3 weeks ×2) administered intravenously before and after surgery. Peripheral blood mononuclear cells (PBMC) that were collected at baseline and week 6 (after ipi) were tested here. Each sample was divided into 5 groups and stimulated with controls or shared melanoma antigen overlapping peptide pools (NY-ESO 1, gp-100, MART-1). Secreted cytokines, chemokines and growth factors were assessed using Luminex. Cytokine expression levels between the 3 antigen groups were compared using the Wilcox rank-sum test.

Results

Seventeen cytokines were differentially expressed with stimulation by each antigen at baseline (p value <0.05): IL1β, MIP1β, IL1RA, VEGF, IL13, IL17, MIP1α, GM-CSF, MCP1, IL5, IL2R, IL4, IL10, IFNγ, TNFα, IL8 and IL2. At week 6, 15 cytokines were differentially expressed (p < 0.05): IL1β, VEGF, G-CSF, HGF, IL13, IL17, GM-CSF, MCP1, IL5, IL7, IL4, IL10, IFNγ, IL8 and IL2. Patients were later clustered based on cytokine expression levels at baseline and at week 6, and recurrence free survival (RFS) was compared. Clear differences in RFS were noted based on cytokine level clustering both at baseline and at week 6: Patients whose PBMCs secreted more cytokines in response to NY-ESO-1 showed a trend towards better RFS.

Conclusions

PBMCs of patients treated with ipi secreted significantly more cytokines, chemokines and growth factors in response to NY-ESO-1 than to gp-100 or MART-1. These cytokines belonged to different functional groups, including inflammatory, type 1, type 2 and regulatory, that warrant further study. Patients whose PBMCs secreted more cytokines (particularly in response to NY-ESO-1) tended to have better RFS, supporting further exploration in terms of therapeutic predictive value.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1140-9) contains supplementary material, which is available to authorized users.

Myeloid-Derived Suppressor Cell Subset Accumulation in Renal Cell Carcinoma Parenchyma Is Associated with Intratumoral Expression of IL1β, IL8, CXCL5, and Mip-1α

Purpose: Little is known about the association between myeloid-derived suppressor cell (MDSC) subsets and various chemokines in patients with renal cell carcinoma (RCC) or the factors that draw MDSC into tumor parenchyma.Experimental Design: We analyzed polymorphonuclear MDSC (PMN-MDSC), monocytic MDSC (M-MDSC), and immature MDSC (I-MDSC) from the parenchyma and peripheral blood of 48 patients with RCC, isolated at nephrectomy. We analyzed levels of IL1β, IL8, CXCL5, Mip-1α, MCP-1, and Rantes. Furthermore, we performed experiments in a Renca murine model to assess therapeutic synergy between CXCR2 and anti-PD1 and to elucidate the impact of IL1β blockade on MDSC.Results: Parenchymal PMN-MDSC have a positive correlation with IL1β, IL8, CXCL5, and Mip-1α, and I-MDSC correlate with IL8 and CXCL5. Furthermore, peripheral PMN-MDSC correlate with tumor grade. Given that PMN-MDSC express CXCR2 and parenchymal PMN-MDSC correlated with IL8 and CXCL5, we assessed the response of CXCR2 blockade with or without anti-PD1. Combination therapy reduced tumor weight and enhanced CD4⁺ and CD8⁺ T-cell infiltration. In addition, anti-IL1β decreased PMN-MDSC and M-MDSC in the periphery, PMN-MDSC in the tumor, and peripheral CXCL5 and KC. Anti-IL1β also delayed tumor growth.Conclusions: Parenchymal PMN-MDSC have a positive correlation with IL1β, IL8, CXCL5, and Mip-1α, suggesting they may attract PMN-MDSC into the tumor. Peripheral PMN-MDSC correlate with tumor grade, suggesting prognostic significance. Anti-CXCR2 and anti-PD1 synergized to reduce tumor weight and enhanced CD4⁺ and CD8⁺ T-cell infiltration in a Renca murine model, suggesting that CXCR2⁺ PMN-MDSC are important in reducing activity of anti-PD1 antibody. Finally, anti-IL1β decreases MDSC and delayed tumor growth, suggesting a potential target for MDSC inhibition. Clin Cancer Res; 23(9); 2346-55. ©2016 AACR.

Neoadjuvant treatment for melanoma: current challenges and future perspectives

There will be an estimated 76,100 new cases of melanoma diagnosed in 2015 and 9710 deaths. Patients with stage I/II disease have excellent outcomes, and the treatment landscape for patients with metastatic disease has been transformed by the approval of several immune checkpoint inhibitors and molecular targeted therapies. Patients with stage III disease, however, continue to have very limited options, as the only agent shown to improve survival in the adjuvant setting is high-dose IFN-α. Neoadjuvant trials of chemotherapy and chemobiotherapy have not been successful, and while neoadjuvant ipilimumab and high-dose interferon have shown promise in small trials, neither agent has been approved. Current trials are testing immune therapy and targeted therapy combinations in the neoadjuvant setting.

Isolated secondary CNS relapse in a case of stage I diffuse large B-cell lymphoma

A 55-year-old woman was admitted to our hospital with a 10-day history of right arm weakness and numbness. The patient's medical history was notable for lobular carcinoma in situ of the right breast in 2008 and stage I diffuse large B-cell lymphoma of the left axilla. The patient had completed treatment with chemotherapy and radiation 2 months prior to presentation. Blood counts, metabolic panel and lumbar puncture were unremarkable. MRI of the brain revealed multiple enhancing masses. The patient was started on dexamethasone, with rapid symptom improvement. A stereotactic brain biopsy revealed CD20 diffuse large B-cell lymphoma. The patient was started on high-dose intravenous methotrexate. She has received 11 cycles and has regained near normal function of the right arm. The patient's most recent brain MRI showed near complete resolution of all previously seen abnormal foci of enhancement.

A 2 weeks on and 1 week off schedule of sunitinib is associated with decreased toxicity in metastatic renal cell carcinoma

Treatment of metastatic renal cell carcinoma (mRCC) with sunitinib is often associated with toxicity necessitating dose reduction. Maintaining adequate dosing and drug levels are essential for optimising clinical efficacy. Standard sunitinib schedule is 4 weeks of treatment and 2 weeks of rest (schedule 4/2). Empirically, several mRCC patients at The Cleveland Clinic (CCF) have been changed from schedule 4/2 to 2 weeks of treatment/1 week off (schedule 2/1) after experiencing toxicity, in an attempt to maintain daily dosing. The medical records of 30 mRCC patients on sunitinib who were changed from schedule 4/2 to schedule 2/1 at CCF were retrospectively reviewed. Toxicity on each schedule was recorded during routine clinic visits and graded using Common Toxicity Criteria, version 4.0. 97% of patients on schedule 4/2 had grade 3 or 4 toxicity that led to changing to schedule 2/1. There were no grade 4 toxicities on schedule 2/1, and 27% of patients experienced grade 3 toxicity (p=0.0001). Two of the most common toxicities, fatigue and hand-foot syndrome (HFS), were significantly less frequent on schedule 2/1 than on schedule 4/2 (p=0.0003; p=0.0004, respectively). Median overall treatment duration on schedule 4/2 was 12.6 months (range 1.2 months-5.1 years) and median overall treatment duration on schedule 2/1 was 11.9 months (range 0.9+ to 73.3+ months). Treatment with sunitinib on schedule 2/1 is associated with significantly decreased toxicity in patients who experience grade 3 or greater toxicity on schedule 4/2, and can extend treatment duration considerably. Prospective clinical trials are required to define the optimal sunitinib schedule to balance efficacy and toxicity.

Clinical perspectives on targeting of myeloid derived suppressor cells in the treatment of cancer

Tumors escape immune recognition by several mechanisms, and induction of myeloid derived suppressor cells (MDSC) is thought to play a major role in tumor mediated immune evasion. MDSC arise from myeloid progenitor cells that do not differentiate into mature dendritic cells, granulocytes, or macrophages, and are characterized by the ability to suppress T cell and natural killer cell function. They are increased in patients with cancer including renal cell carcinoma (RCC), and their levels have been shown to correlate with prognosis and overall survival. Multiple methods of inhibiting MDSCs are currently under investigation. These can broadly be categorized into methods that (a) promote differentiation of MDSC into mature, non-suppressive cells (all trans retinoic acid, vitamin D), (b) decrease MDSC levels (sunitinib, gemcitabine, 5-FU, CDDO-Me), or (c) functionally inhibit MDSC (PDE-5 inhibitors, cyclooxygenase 2 inhibitors). Recently, several pre-clinical tumor models of combination therapy involving sunitinib plus vaccines and/or adoptive therapy have shown promise in MDSC inhibition and improved outcomes in the tumor bearing host. Current clinical trials are underway in RCC patients to assess not only the impact on clinical outcome, but how this combination can enhance anti-tumor immunity and reduce immune suppression. Decreasing immune suppression by MDSC in the cancer host may improve outcomes and prolong survival in this patient population.

Novel agents in renal carcinoma: a reality check

The discovery of the molecular mechanisms underlying development of renal cell carcinoma have allowed for the development of novel targeted therapy for treatment of this disease. Recently, multiple agents have become approved by regulatory authorities for the treatment of advanced renal cell carcinoma, including sunitinib, sorafenib, bevacizumab (with interferon alpha), pazopanib, temsirolimus and everolimus. While these therapies have generated excitement and have clearly altered the treatment paradigm, multiple limitations have been elucidated over time. These include but are not limited to the fact that treatment is not associated with complete responses, a significant number of patients are primarily refractory to treatment, and clinical trials mostly include clear cell histology. Furthermore, the role of these therapies in the treatment of brain metastases remains unclear and therapies can have considerable toxicities. RECIST criteria (Response Evaluation Criteria In Solid Tumors) can be inadequate for the assessment of these modalities' treatment efficacy, and biomarkers predictive of individual patient benefit have been elusive. This review summarizes the major clinical data and discusses these limitations.

B7-DC-Ig enhances vaccine effect by a novel mechanism dependent on PD-1 expression level on T cell subsets

Programmed death receptor 1 (PD-1) is an important signaling molecule often involved in tumor-mediated suppression of activated immune cells. Binding of this receptor to its ligands, B7-H1 (PD-L1) and B7-DC (PD-L2), attenuates T cell activation, reduces IL-2 and IFN-γ secretion, decreases proliferation and cytotoxicity, and induces apoptosis. B7-DC-Ig is a recombinant protein that binds and targets PD-1. It is composed of an extracellular domain of murine B7-DC fused to the Fc portion of murine IgG2a. In this study, we demonstrate that B7-DC-Ig can enhance the therapeutic efficacy of vaccine when combined with cyclophosphamide. We show that this combination significantly enhances Ag-specific immune responses and leads to complete eradication of established tumors in 60% of mice and that this effect is CD8 dependent. We identified a novel mechanism by which B7-DC-Ig exerts its therapeutic effect that is distinctly different from direct blocking of the PD-L1-PD-1 interaction. In this study, we demonstrate that there are significant differences between levels and timing of surface PD-1 expression on different T cell subsets. We found that these differences play critical roles in anti-tumor immune effect exhibited by B7-DC-Ig through inhibiting proliferation of PD-1(high) CD4 T cells, leading to a significant decrease in the level of these cells, which are enriched for regulatory T cells, within the tumor. In addition, it also leads to a decrease in PD-1(high) CD8 T cells, tipping the balance toward nonexhausted functional PD-1(low) CD8 T cells. We believe that the PD-1 expression level on T cells is a crucial factor that needs to be considered when designing PD-1-targeting immune therapies.

Anti-PD-1 synergizes with cyclophosphamide to induce potent anti-tumor vaccine effects through novel mechanisms

Programmed death-1 receptor (PD-1) is expressed on T cells following TCR activation. Binding of this receptor to its cognate ligands, programmed death ligand (PDL)-1 and PDL-2, down-regulates signals by the TCR, promoting T-cell anergy and apoptosis, thus leading to immune suppression. Here, we find that using an anti-PD-1 antibody (CT-011) with Treg-cell depletion by low-dose cyclophosphamide (CPM), combined with a tumor vaccine, induces synergistic antigen-specific immune responses and reveals novel activities of each agent in this combination. This strategy led to complete regression of established tumors in a significant percentage of treated animals, with survival prolongation. We show for the first time that combining CT-011 and CPM significantly increases the number of vaccine-induced tumor-infiltrating CD8(+) T cells, with simultaneous decrease in infiltrating Treg cells. Interestingly, we find that CT-011 prolongs Treg-cell inhibition induced by CPM, leading to a sustainable significant synergistic decrease of splenic and tumor-infiltrated Treg cells. Surprisingly, we find that the anti-tumor effect elicited by the combination of CT-011 and CPM is dependent on both CD8(+) and CD4(+) T-cell responses, although the antigen we used is a class I MHC-restricted peptide. Thus, we describe a novel and effective therapeutic approach by combining multiple strategies to target several tumor-mediated immune inhibitory mechanisms.