Treatment of metastatic uveal melanoma with adoptive transfer of tumour-infiltrating lymphocytes: a single-centre, two-stage, single-arm, phase 2 study

A Comprehensive Prognostic and Immunological Analysis of a Six-Gene Signature Associated With Glycolysis and Immune Response in Uveal Melanoma

Uveal melanoma (UM) is a subtype of melanoma with poor prognosis. This study aimed to construct a new prognostic gene signature that can be used for survival prediction and risk stratification of UM patients. In this work, transcriptome data from the Molecular Signatures Database were used to identify the cancer hallmarks most relevant to the prognosis of UM patients. Weighted gene co-expression network, univariate least absolute contraction and selection operator (LASSO), and multivariate Cox regression analyses were used to construct the prognostic gene characteristics. Kaplan-Meier and receiver operating characteristic (ROC) curves were used to evaluate the survival predictive ability of the gene signature. The results showed that glycolysis and immune response were the main risk factors for overall survival (OS) in UM patients. Using univariate Cox regression analysis, 238 candidates related to the prognosis of UM patients were identified (p < 0.05). Using LASSO and multivariate Cox regression analyses, a six-gene signature including ARPC1B, BTBD6, GUSB, KRTCAP2, RHBDD3, and SLC39A4 was constructed. Kaplan-Meier analysis of the UM cohort in the training set showed that patients with higher risk scores had worse OS (HR = 2.61, p < 0.001). The time-dependent ROC (t-ROC) curve showed that the risk score had good predictive efficiency for UM patients in the training set (AUC > 0.9). Besides, t-ROC analysis showed that the predictive ability of risk scores was significantly higher than that of other clinicopathological characteristics. Univariate and multivariate Cox regression analyses showed that risk score was an independent risk factor for OS in UM patients. The prognostic value of risk scores was further verified in two external UM cohorts (GSE22138 and GSE84976). Two-factor survival analysis showed that UM patients with high hypoxia or immune response scores and high risk scores had the worst prognosis. Moreover, a nomogram based on the six-gene signature was established for clinical practice. In addition, risk scores were related to the immune infiltration profiles. Taken together, this study identified a new prognostic six-gene signature related to glycolysis and immune response. This six-gene signature can not only be used for survival prediction and risk stratification but also may be a potential therapeutic target for UM patients.

Nivolumab for patients with metastatic uveal melanoma previously untreated with ipilimumab: a single-institution retrospective study

We evaluated the efficacy of nivolumab in patients with metastatic uveal melanoma previously untreated with ipilimumab. We performed a retrospective study at the National Cancer Center Hospital in Tokyo, Japan, where nivolumab was approved 1 year earlier than ipilimumab. Clinical efficacy outcomes were determined by assessing best overall response according to the Response Evaluation Criteria in Solid Tumors (version 1.1), progression-free survival and overall survival. Fourteen patients were analyzed; none had received any prior systemic therapies although eight had undergone transarterial chemoembolization. The median follow-up period was 15 months. The objective response and disease control rates were 7.1% and 42.9%, respectively (one partial response and five stable diseases). The median progression-free survival and overall survival were 10 (range, 4-105) and 60 (range, 5-105) weeks, respectively. Liver metastases in three patients were all programmed cell death-1 ligand negative. Lower lactate dehydrogenase, development of vitiligo, and a neutrophil-to-lymphocyte ratio less than 5 at week 6 were associated with favorable progression-free survival and overall survival; of these, only a neutrophil-to-lymphocyte ratio less than 5 at week 6 was statistically significant. Even with the use of nivolumab before ipilimumab, metastatic uveal melanoma appears to remain refractory to nivolumab monotherapy. However, because one patient in our cohort achieved an objective response, and the median overall survival exceeded 1 year, treatment strategies that incorporate anti-PD1 antibody should be further investigated. Whether a neutrophil-to-lymphocyte ratio less than 5 at week 6 is a favorable early on-treatment marker should be validated in larger cohorts.

Locoregional Therapies for the Treatment of Uveal Melanoma Hepatic Metastases

Uveal melanoma is the most common primary intraocular malignant tumor in adults. Approximately 50% of patients develop metastatic disease of which greater than 90% of patients develop hepatic metastases. Following the development of liver tumors, overall survival is dismal with hepatic failure being the cause of death in nearly all cases. To prolong survival for patients with metastatic uveal melanoma, controlling the growth of hepatic tumors is essential. This article will discuss imaging surveillance following the diagnosis of primary uveal melanoma; locoregional therapies used to control the growth of hepatic metastases including chemoembolization, immunoembolization, radioembolization, percutaneous hepatic perfusion, and thermal ablation; as well as currently available systemic treatment options for metastatic uveal melanoma.

Role of Natural Killer Cells in Uveal Melanoma

Simple Summary

Metastatic Uveal Melanoma (MUM) is a lethal malignancy with no durable treatment available to date. A vast majority of patients with MUM present with liver metastasis. The liver harbors metastatic disease with an apparent lack of a cytotoxic T cell response. It is becoming evident that MUM is not an immunologically silent malignancy and the investigation of non-T cell anti-tumor immunity is warranted. In this review, we highlight the relevance of Natural Killer (NK) cells in the biology and treatment of MUM. Potent anti-NK cell immunosuppression employed by uveal melanoma alludes to its vulnerability to NK cell cytotoxicity. On the contrary, micro-metastasis in the liver survive for several years within close vicinity of a plethora of circulating and liver-resident NK cells. This review provides unique perspectives into the potential role of NK cells in control or progression of uveal melanoma.

Abstract

Uveal melanoma has a high mortality rate following metastasis to the liver. Despite advances in systemic immune therapy, treatment of metastatic uveal melanoma (MUM) has failed to achieve long term durable responses. Barriers to success with immune therapy include the immune regulatory nature of uveal melanoma as well as the immune tolerant environment of the liver. To adequately harness the anti-tumor potential of the immune system, non-T cell-based approaches need to be explored. Natural Killer (NK) cells possess potent ability to target tumor cells via innate and adaptive responses. In this review, we discuss evidence that highlights the role of NK cell surveillance and targeting of uveal melanoma. We also discuss the repertoire of intra-hepatic NK cells. The human liver has a vast and diverse lymphoid population and NK cells comprise 50% of the hepatic lymphocytes. Hepatic NK cells share a common niche with uveal melanoma micro-metastasis within the liver sinusoids. It is, therefore, crucial to understand and investigate the role of intra-hepatic NK cells in the control or progression of MUM.

Comprehensive analysis of cutaneous and uveal melanoma liver metastases

BACKGROUND

The profound disparity in response to immune checkpoint blockade (ICB) by cutaneous melanoma (CM) and uveal melanoma (UM) patients is not well understood. Therefore, we characterized metastases of CM and UM from the same metastatic site (liver), in order to dissect the potential underlying mechanism in differential response on ICB.

METHODS

Tumor liver samples from CM (n=38) and UM (n=28) patients were analyzed at the genomic (whole exome sequencing), transcriptional (RNA sequencing) and protein (immunohistochemistry and GeoMx Digital Spatial Profiling) level.

RESULTS

Comparison of CM and UM metastases from the same metastatic site revealed that, although originating from the same melanocyte lineage, CM and UM differed in somatic mutation profile, copy number profile, tumor mutational burden (TMB) and consequently predicted neoantigens. A higher melanin content and higher expression of the melanoma differentiation antigen MelanA was observed in liver metastases of UM patients. No difference in B2M and human leukocyte antigen-DR (HLA-DR) expression was observed. A higher expression of programmed cell death ligand 1 (PD-L1) was found in CM compared with UM liver metastases, although the majority of CM and UM liver metastases lacked PD-L1 expression. There was no difference in the extent of immune infiltration observed between CM and UM metastases, with the exception of a higher expression of CD163 (p<0.0001) in CM liver samples. While the extent of immune infiltration was similar for CM and UM metastases, the ratio of exhausted CD8 T cells to cytotoxic T cells, to total CD8 T cells and to Th1 cells, was significantly higher in UM metastases.

CONCLUSIONS

While TMB was different between CM and UM metastases, tumor immune infiltration was similar. The greater dependency on PD-L1 as an immune checkpoint in CM and the identification of higher exhaustion ratios in UM may both serve as explanations for the difference in response to ICB. Consequently, in order to improve current treatment for metastatic UM, reversal of T cell exhaustion beyond programmed cell death 1 blockade should be considered.

Engineering microrobots for targeted cancer therapies from a medical perspective

Systemic chemotherapy remains the backbone of many cancer treatments. Due to its untargeted nature and the severe side effects it can cause, numerous nanomedicine approaches have been developed to overcome these issues. However, targeted delivery of therapeutics remains challenging. Engineering microrobots is increasingly receiving attention in this regard. Their functionalities, particularly their motility, allow microrobots to penetrate tissues and reach cancers more efficiently. Here, we highlight how different microrobots, ranging from tailor-made motile bacteria and tiny bubble-propelled microengines to hybrid spermbots, can be engineered to integrate sophisticated features optimised for precision-targeting of a wide range of cancers. Towards this, we highlight the importance of integrating clinicians, the public and cancer patients early on in the development of these novel technologies.

Immune gene therapy of cancer

Cancer gene therapy emerged as a promising treatment modality 3 decades ago. However, the failure of the first gene therapy trials in cancer treatment has decreased its popularity. Likewise, immunotherapy has followed a similar course. While it was a popular and promising treatment with IL-2 and interferon and cancer vaccines in the 1980s, it later lost its popularity. Immunotherapy became one of the main options for cancer treatment with the successful use of immune checkpoint inhibitors in clinics approximately 10 years ago. The success of immunotherapy has increased even more with the introduction of cancer gene therapy methods in this area. With the identification of the oncolytic herpes simplex virus and Chimeric antigen receptor (CAR) T-cells, immune gene therapy has become an essential modality in cancer treatments such as surgery, radiotherapy, chemotherapy, and targeted therapies.

Publication trends of research on uveal melanoma during 2000-2020: a 20-year bibliometric study

Uveal melanoma (UM) is the most prevalent primary intraocular malignancy in adults. Despite a high rate of success in controlling it as a local disease, it is prone to distant metastasis, and its mechanism of metastasis has not been elucidated. This study analyzes trends in UM research and compares contributions from different countries, regions, institutions and authors. We collected all publications related to UM published from 2000 to 2020 from the Web of Science database. GraphPad Prism 6 was used to collect publication data and analyze publication trends. VOSviewer was used for data visualization. A total of 1,710 publications were considered. The United States contributed the most publications [668] and citations (19,605 times) as of 2020 with the highest H-index value [67]. Keywords were classified into three clusters, namely, clinical study, tumor-related study and gene mutation-related study. Average appearing years (AAY) of keywords were calculated. BAP1 (AAY of 2016.3), SF3B1 (AAY of 2015.8) and GNA11 (AAY of 2015.5) were identified as major focuses of this field. We conclude that the United States, Germany, England and the Netherlands have been the most productive regions in terms of UM research over the past two decades. Gene mutations such as GNAQ, GNA11 and BAP1 mutations are identified as potential research focuses.

Uveal melanoma: progress in molecular biology and therapeutics

Uveal melanoma (UM) is the most common intraocular malignancy in adults. So far, no systemic therapy or standard treatment exists to reduce the risk of metastasis and improve overall survival of patients. With the increased knowledge regarding the molecular pathways that underlie the oncogenesis of UM, it is expected that novel therapeutic approaches will be available to conquer this disease. This review provides a summary of the current knowledge of, and progress made in understanding, the pathogenesis, genetic mutations, epigenetics, and immunology of UM. With the advent of the omics era, multi-dimensional big data are publicly available, providing an innovation platform to develop effective targeted and personalized therapeutics for UM patients. Indeed, recently, a great number of therapies have been reported specifically for UM caused by oncogenic mutations, as well as other etiologies. In this review, special attention is directed to advancements in targeted therapies. In particular, we discuss the possibilities of targeting: GNAQ/GNA11, PLCβ, and CYSLTR2 mutants; regulators of G-protein signaling; the secondary messenger adenosine diphosphate (ADP)-ribosylation factor 6 (ARF6); downstream pathways, such as those involving mitogen-activated protein kinase/MEK/extracellular signal-related kinase, protein kinase C (PKC), phosphoinositide 3-kinase/Akt/mammalian target of rapamycin (mTOR), Trio/Rho/Rac/Yes-associated protein, and inactivated BAP1; and immune-checkpoint proteins cytotoxic T-lymphocyte antigen 4 and programmed cell-death protein 1/programmed cell-death ligand 1. Furthermore, we conducted a survey of completed and ongoing clinical trials applying targeted and immune therapies for UM. Although drug combination therapy based on the signaling pathways involved in UM has made great progress, targeted therapy is still an unmet medical need.

Transcriptome Profiling Reveals New Insights into the Immune Microenvironment and Upregulation of Novel Biomarkers in Metastatic Uveal Melanoma

Simple Summary

Uveal melanoma (UM) is a rare aggressive eye cancer. Although treatment of the eye tumour is successful, about 50% of UM patients develop a relapse of their cancer in the liver. At present, such advanced disease is not curable. A better understanding of the metastatic UM (mUM) in the liver is essential to improve patient survival. This study examines both the response of immune cells within the liver to the UM secondaries (metastases), as well as the expression of various proteins by the UM cells. Our study demonstrates that there is a limited immune response to the mUM, but reveals that a certain type of reactive immune cell: a protumourigenic subset of macrophage is dominant within the mUM. Our research also reveals novel proteins within the mUM, which are specific to these cells and therefore may be targetable in future therapies.

Abstract

Metastatic uveal melanoma (mUM) to the liver is incurable. Transcriptome profiling of 40 formalin-fixed paraffin-embedded mUM liver resections and 6 control liver specimens was undertaken. mUMs were assessed for morphology, nuclear BAP1 (nBAP1) expression, and their tumour microenvironments (TME) using an “immunoscore” (absent/altered/high) for tumour-infiltrating lymphocytes (TILs) and macrophages (TAMs). Transcriptomes were compared between mUM and control liver; intersegmental and intratumoural analyses were also undertaken. Most mUM were epithelioid cell-type (75%), amelanotic (55%), and nBAP1-ve (70%). They had intermediate (68%) or absent (15%) immunoscores for TILs and intermediate (53%) or high (45%) immunoscores for TAMs. M2-TAMs were dominant in the mUM-TME, with upregulated expression of ANXA1, CD74, CXCR4, MIF, STAT3, PLA2G6, and TGFB1. Compared to control liver, mUM showed significant (p < 0.01) upregulation of 10 genes: DUSP4, PRAME, CD44, IRF4/MUM1, BCL2, CD146/MCAM/MUC18, IGF1R, PNMA1, MFGE8/lactadherin, and LGALS3/Galectin-3. Protein expression of DUSP4, CD44, IRF4, BCL-2, CD146, and IGF1R was validated in all mUMs, whereas protein expression of PRAME was validated in 10% cases; LGALS3 stained TAMs, and MFGEF8 highlighted bile ducts only. Intersegmental mUMs show differing transcriptomes, whereas those within a single mUM were similar. Our results show that M2-TAMs dominate mUM-TME with upregulation of genes contributing to immunosuppression. mUM significantly overexpress genes with targetable signalling pathways, and yet these may differ between intersegmental lesions.

Molecular Insights and Emerging Strategies for Treatment of Metastatic Uveal Melanoma

Uveal melanoma (UM) is the most common intraocular cancer. In recent decades, major advances have been achieved in the diagnosis and prognosis of UM allowing for tailored treatments. However, nearly 50% of patients still develop metastatic disease with survival rates of less than 1 year. There is currently no standard of adjuvant and metastatic treatment in UM, and available therapies are ineffective resulting from cutaneous melanoma protocols. Advances and novel treatment options including liver-directed therapies, immunotherapy, and targeted-therapy have been investigated in UM-dedicated clinical trials on single compounds or combinational therapies, with promising results. Therapies aimed at prolonging or targeting metastatic tumor dormancy provided encouraging results in other cancers, and need to be explored in UM. In this review, the latest progress in the diagnosis, prognosis, and treatment of UM in adjuvant and metastatic settings are discussed. In addition, novel insights into tumor genetics, biology and immunology, and the mechanisms underlying metastatic dormancy are discussed. As evident from the numerous studies discussed in this review, the increasing knowledge of this disease and the promising results from testing of novel individualized therapies could offer future perspectives for translating in clinical use.

Characteristics of Malignant Pleural Effusion Resident CD8+ T Cells from a Heterogeneous Collection of Tumors

While T cell-based cancer immunotherapies have shown great promise, there remains a need to understand how individual metastatic tumor environments impart local T cell dysfunction. At advanced stages, cancers that metastasize to the pleural space can result in a malignant pleural effusion (MPE) that harbors abundant tumor and immune cells, often exceeding 10⁸ leukocytes per liter. Unlike other metastatic sites, MPEs are readily and repeatedly accessible via indwelling catheters, providing an opportunity to study the interface between tumor dynamics and immunity. In the current study, we examined CD8⁺ T cells within MPEs collected from patients with heterogeneous primary tumors and at various stages in treatment to determine (1) if these cells possess anti-tumor activity following removal from the MPE, (2) factors in the MPE that may contribute to their dysfunction, and (3) the phenotypic changes in T cell populations that occur following ex vivo expansion. Co-cultures of CD8⁺ T cells with autologous CD45^- tumor containing cells demonstrated cytotoxicity (p = 0.030) and IFNγ production (p = 0.003) that inversely correlated with percent of myeloid derived suppressor cells, lactate, and lactate dehydrogenase (LDH) within the MPE. Ex vivo expansion of CD8⁺ T cells resulted in progressive differentiation marked by distinct populations expressing decreased CD45RA, CCR7, CD127, and increased inhibitory receptors. These findings suggest that MPEs may be a source of tumor-reactive T cells and that the cellular and acellular components suppress optimal function.

Circular RNA has circ 0001591 promoted cell proliferation and metastasis of human melanoma via ROCK1/PI3K/AKT by targeting miR-431-5p

Melanoma a common skin tumor induced by excessive hyperplasia of abnormal melanocyte. Circular RNAs (circRNAs) play critical roles in various diseases and presented as the prognostic markers of melanoma. The present study was designed to confirm the effect of circ 0001591 on human melanoma cell growth and to elucidate its mechanism. Patient with melanoma was obtained from Shaanxi Provincial People's Hospital. Cell viability of A2058 cell was detected by MTT assay. The expression of circ 0001591 in serum of patients with melanoma was increased. Up-regulation of circ 0001591 promoted cell growth and cell invasion, and reduced apoptotic rate of melanoma. Down-regulation of circ 0001591 reduced cell growth and cell invasion, and promoted apoptotic rate of melanoma.Up-regulation of circ 0001591 induced PI3 K and p-Akt protein expressions in melanoma through induction of ROCK1 by suppression of miR-431-5p. Over-expression of circ 0001591 suppressed PI3 K and p-Akt protein expressions via suppression of ROCK1 in melanoma by induction of miR-431-5p. MiR-431-5p reduced the effects of circ 0001591 down-regulation on cell growth of melanoma through PI3K/AKT signal pathway. ROCK1 reduced the effects of circ 0001591 on cell growth of melanoma through PI3K/AKT signal pathway. Our findings demonstrated that circ 0001591 inhibits the progression of human melanoma through ROCK1/PI3K/AKT signal pathway by targeting ROCK1 by miR-431-5p.

LncRNA SNHG15 predicts poor prognosis in uveal melanoma and its potential pathways

AIM

To evaluate the role of long noncoding RNA (lncRNA) SNHG15 and its potential pathways in uveal melanoma (UM).

METHODS

The SNHG15 mRNA expression level and corresponding clinicopathological characteristics of 80 patients with UM were obtained from the Cancer Genome Atlas (TCGA) database and further analyzed. The SPSS 24.0 statistical software package was used for statistical analyses. To investigate the potential function of SNHG15 in UM, we conducted in-depth research on Gene Set Enrichment Analysis (GSEA).

RESULTS

The univariate analysis revealed that the age, tumor diameter, pathological type, extrascleral extension, cancer status, and high expression of SNHG15 were statistical risk factors for death from all causes. The multivariate analysis suggested that the mRNA expression level of SNHG15 was an independent risk factor for death from all causes, as was age and pathological type. Kaplan-Meier survival analysis confirmed that UM patients with high SNHG15 expression might have a poor prognosis. In addition, SNHG15 was significantly differentially expressed in the different groups of tumor pathologic stage, metastasis and living status. Besides, the logistic regression analysis indicated that high SNHG15 expression group in UM was significantly associated with cancer status, pathologic stage, metastasis, and living status. Moreover, the GSEA indicated the potential pathways regulated by SNHG15 in UM.

CONCLUSION

Our research suggests that SNHG15 may play a vital role as a potential marker in UM that predicts poor prognosis. Besides, GSEA indicates the underlying signaling pathways enriched differentially in SNHG15 high expression phenotype.

Novel Approaches to the Systemic Management of Uveal Melanoma

PURPOSE OF REVIEW

Uveal melanoma is a distinct subtype of melanoma characterized by a unique biology and divergent response to immune therapies. In this review, we will discuss our current understanding of the pathophysiology of uveal melanoma, systemic treatment options for advanced disease, and potential future therapeutic directions.

RECENT FINDINGS

Although treatment with single-agent checkpoint blockade has been generally disappointing, the results of combined checkpoint blockade are modestly more promising. Several alternative systemic therapeutic approaches have been or are currently being investigated, including two agents that have been taken into registration-intent clinical trials: tebentafusp, a T cell redirecting agent, and IDE196, an oral protein kinase C inhibitor. Treatment of advanced uveal melanoma remains challenging, however, encouraging results from novel agents offer hope for improvement in the near future.

Reactive Myelopoiesis Triggered by Lymphodepleting Chemotherapy Limits the Efficacy of Adoptive T Cell Therapy

Adoptive T cell therapy (ACT) in combination with lymphodepleting chemotherapy is an effective strategy to induce the eradication of tumors, providing long-term regression in cancer patients. Despite that lymphodepleting regimens condition the host for optimal engraftment and expansion of adoptively transferred T cells, lymphodepletion concomitantly promotes immunosuppression during the course of endogenous immune recovery. In this study, we have identified that lymphodepleting chemotherapy initiates the mobilization of hematopoietic progenitor cells that differentiate to immunosuppressive myeloid cells, leading to a dramatic increase of peripheral myeloid-derived suppressor cells (MDSCs). In melanoma and lung cancer patients, MDSCs rapidly expanded in the periphery within 1 week after completion of a lymphodepleting regimen and infusion of autologous tumor-infiltrating lymphocytes (TILs). This expansion was associated with disease progression, poor survival, and reduced TIL persistence in melanoma patients. We demonstrated that the interleukin 6 (IL-6)-driven differentiation of mobilized hematopoietic progenitor cells promoted the survival and immunosuppressive capacity of post-lymphodepletion MDSCs. Furthermore, the genetic abrogation or therapeutic inhibition of IL-6 in mouse models enhanced host survival and reduced tumor growth in mice that received ACT. Thus, the expansion of MDSCs in response to lymphodepleting chemotherapy may contribute to ACT failure, and targeting myeloid-mediated immunosuppression may support anti-tumor immune responses.

Engineering bionic T cells: signal 1, signal 2, signal 3, reprogramming and the removal of inhibitory mechanisms

Gene engineering and combinatorial approaches with other cancer immunotherapy agents may confer capabilities enabling full tumor rejection by adoptive T cell therapy (ACT). The provision of proper costimulatory receptor activity and cytokine stimuli, along with the repression of inhibitory mechanisms, will conceivably make the most of these treatment strategies. In this sense, T cells can be genetically manipulated to become refractory to suppressive mechanisms and exhaustion, last longer and differentiate into memory T cells while endowed with the ability to traffic to malignant tissues. Their antitumor effects can be dramatically augmented with permanent or transient gene transfer maneuvers to express or delete/repress genes. A combination of such interventions seeks the creation of the ultimate bionic T cell, perfected to seek and destroy cancer cells upon systemic or local intratumor delivery.

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.

Uveal melanoma pathobiology: Metastasis to the liver

Uveal melanoma (UM) is a type of intraocular tumor with a propensity to disseminate to the liver. Despite the identification of the early driver mutations during the development of the pathology, the process of UM metastasis is still not fully comprehended. A better understanding of the genetic, molecular, and environmental factors participating to its spread and metastatic outgrowth could provide additional approaches for UM treatment. In this review, we will discuss the advances made towards the understanding of the pathogenesis of metastatic UM, summarize the current and prospective treatments, and introduce some of the ongoing research in this field.

The Outcome of Ex Vivo TIL Expansion Is Highly Influenced by Spatial Heterogeneity of the Tumor T-Cell Repertoire and Differences in Intrinsic In Vitro Growth Capacity between T-Cell Clones

PURPOSE

During our efforts to develop tumor-infiltrating lymphocyte (TIL) therapy to counter the devastating recurrence rate in patients with primary resectable pancreatic ductal adenocarcinoma (PDA), we found that PDA TILs can readily be expanded in vitro and that the majority of resulting TIL cultures show reactivity against the autologous tumor. However, the fraction of tumor-reactive T cells is low. We investigated to which extent this was related to the in vitro expansion.

EXPERIMENTAL DESIGN

We compared the clonal composition of TIL preparations before and after in vitro expansion using T-cell receptor (TCR) deep sequencing. Our findings for PDA were benchmarked to experiments with melanoma TILs.

RESULTS

We found that the TIL TCR repertoire changes dramatically during in vitro expansion, leading to loss of tumor- dominant T-cell clones and overgrowth by newly emerging T-cell clones that are barely detectable in the tumor. These changes are primarily driven by differences in the intrinsic in vitro expansion capacity of T-cell clones. Single-cell experiments showed an association between poor proliferative capacity and expression of markers related to antigen experience and dysfunction. Furthermore, we found that spatial heterogeneity of the TIL repertoire resulted in TCR repertoires that are greatly divergent between TIL cultures derived from distant tumor samples of the same patient.

CONCLUSIONS

Culture-induced changes in clonal composition are likely to affect tumor reactivity of TIL preparations. TCR deep sequencing provides important insights into the factors that govern the outcome of in vitro TIL expansion and thereby a path toward optimization of the production of TIL preparations with high therapeutic efficacy.See related commentary by Lozano-Rabella and Gros, p. 4177.

Uveal melanoma

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. UMs are usually initiated by a mutation in GNAQ or GNA11, unlike cutaneous melanomas, which usually harbour a BRAF or NRAS mutation. The annual incidence in Europe and the USA is ~6 per million population per year. Risk factors include fair skin, light-coloured eyes, congenital ocular melanocytosis, ocular melanocytoma and the BAP1-tumour predisposition syndrome. Ocular treatment aims at preserving the eye and useful vision and, if possible, preventing metastases. Enucleation has largely been superseded by various forms of radiotherapy, phototherapy and local tumour resection, often administered in combination. Ocular outcomes are best with small tumours not extending close to the optic disc and/or fovea. Almost 50% of patients develop metastatic disease, which usually involves the liver, and is usually fatal within 1 year. Although UM metastases are less responsive than cutaneous melanoma to chemotherapy or immune checkpoint inhibitors, encouraging results have been reported with partial hepatectomy for solitary metastases, with percutaneous hepatic perfusion with melphalan or with tebentafusp. Better insight into tumour immunology and metabolism may lead to new treatments.

Talkin' Toxins: From Coley's to Modern Cancer Immunotherapy

The ability of the immune system to precisely target and eliminate aberrant or infected cells has long been studied in the field of infectious diseases. Attempts to define and exploit these potent immunological processes in the fight against cancer has been a longstanding effort dating back over 100 years to when Dr. William Coley purposefully infected cancer patients with a cocktail of heat-killed bacteria to stimulate anti-cancer immune processes. Although the field of cancer immunotherapy has been dotted with skepticism at times, the success of immune checkpoint inhibitors and recent FDA approvals of autologous cell therapies have pivoted immunotherapy to center stage as one of the most promising strategies to treat cancer. This review aims to summarize historic milestones throughout the field of cancer immunotherapy as well as highlight current and promising immunotherapies in development.

Loss of BAP1 expression is associated with an immunosuppressive microenvironment in uveal melanoma, with implications for immunotherapy development

Immunotherapy using immune checkpoint inhibitors (ICIs) induces durable responses in many metastatic cancers. Metastatic uveal melanoma (mUM), typically occurring in the liver, is one of the most refractory tumours to ICIs and has dismal outcomes. Monosomy 3 (M3), polysomy 8q, and BAP1 loss in primary uveal melanoma (pUM) are associated with poor prognoses. The presence of tumour-infiltrating lymphocytes (TILs) within pUM and surrounding mUM - and some evidence of clinical responses to adoptive TIL transfer - strongly suggests that UMs are indeed immunogenic despite their low mutational burden. The mechanisms that suppress TILs in pUM and mUM are unknown. We show that BAP1 loss is correlated with upregulation of several genes associated with suppressive immune responses, some of which build an immune suppressive axis, including HLA-DR, CD38, and CD74. Further, single-cell analysis of pUM by mass cytometry confirmed the expression of these and other markers revealing important functions of infiltrating immune cells in UM, most being regulatory CD8+ T lymphocytes and tumour-associated macrophages (TAMs). Transcriptomic analysis of hepatic mUM revealed similar immune profiles to pUM with BAP1 loss, including the expression of IDO1. At the protein level, we observed TAMs and TILs entrapped within peritumoural fibrotic areas surrounding mUM, with increased expression of IDO1, PD-L1, and β-catenin (CTNNB1), suggesting tumour-driven immune exclusion and hence the immunotherapy resistance. These findings aid the understanding of how the immune response is organised in BAP1 - mUM, which will further enable functional validation of detected biomarkers and the development of focused immunotherapeutic approaches. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Identification of an immune-related signature for the prognosis of uveal melanoma

AIM

To construct an immune-related prognostic signature (IPS) that can distinguish and predict prognosis in uveal melanoma (UM).

METHODS

The transcriptomic data and clinicopathological information of 80 UM patients were extracted from the TCGA database. These patients were randomly assigned to a training and a testing set.

RESULTS

Lasso Cox analysis was performed for the prognostic immune-related genes to develop an IPS for UM in the training set. The signature was validated in both the testing set and entire cohort. We confirmed the prognostic value of our IPS in distinct subgroups and found its association with the T stage and basal diameter of the tumor. Tumor Immune Estimation Resource database analysis revealed that the IPS was negatively correlated with the infiltration of neutrophils and dendritic cells, but positively correlated with the infiltration level of CD8+ T cells. In addition, we demonstrated that immune checkpoints containing PD-1, CTLA-4, IDO, and TIGIT were moderately associated with the IPS.

CONCLUSION

This is the first study to develop and validate an immune-related signature with the ability of predicting prognosis for UM patients. Further studies are needed to validate its prediction accuracy.

Cytologic Evaluation of Tumor-Infiltrating Lymphocytes for Adoptive Cell Therapy

OBJECTIVES

Novel immunotherapeutic options for refractory metastatic cancer patients include adoptive cell therapies such as tumor infiltrating lymphocytes (TILs). This study characterizes the clinicopathologic findings in a cohort of TIL specimens.

METHODS

Patients with metastatic malignancy who were eligible had TILs from their metastases grown and expanded and then sent to pathology.

RESULTS

A total of 11 TIL specimens (10 melanoma, 1 adenocarcinoma) from patients enrolled in an experimental clinical trial were reviewed. All specimens showed more than 200 lymphoid cells, stained positive for lymphoid markers confirming an activated cytotoxic T-cell immunophenotype, and morphologically showed an intermediate-sized population with immature chromatin and frequent mitoses. Six cases (55%) showed large cells with nucleomegaly and prominent nucleoli.

CONCLUSIONS

This report is the first describing cytopathologic findings of autologous TIL therapy including adequacy guidelines and expected cytomorphologic and immunophenotypic findings. To meet this novel clinical demand, a predefined cytology protocol to rapidly process and interpret these specimens needs to be established.

Survival after checkpoint inhibitors for metastatic acral, mucosal and uveal melanoma

BACKGROUND

Checkpoint inhibitors (CPIs) are thought to be effective against cutaneous melanoma in part because of the large burden of somatic mutations (neoantigens) generated from exposure to ultraviolet radiation. However, rare melanoma subtypes arising from acral skin, mucosal surfaces, and the uveal tract are largely sun-shielded. Genomic studies show these sun-shielded melanomas have a paucity of neoantigens and unique biology; they are thought to be largely resistant to immunotherapy. It has not been definitively shown that CPI improves survival in metastatic sun-shielded melanoma.

METHODS

We reviewed a single institutional experience using antibodies against CTLA-4, PD-1 and/or PD-L1 to treat patients with metastatic melanoma. Primary tumor histology was categorized as cutaneous, unknown, acral, mucosal, or uveal. We studied demographic data, treatment characteristics, and overall survival (OS) after CPI.

RESULTS

We treated 428 patients with metastatic melanoma from 2007 to 2019. Primary tumors were cutaneous in 283 (66%), unknown in 55 (13%), acral in 22 (5%), mucosal in 38 (9%), and uveal in 30 (7%). Patients with metastatic disease from cutaneous primary tumors had median OS after CPI of 45 months compared with 17 months for acral (p=0.047), 18 months for mucosal (p=0.003), and 12 months for uveal (p<0.001). For all patients with sun-shielded melanoma (n=90), first treatment with anti-PD-1 or anti-PD-L1 was followed by a median OS of 9 months compared with 18 months after anti-CTLA-4 (p=0.010) and 20 months after combination therapy (p=0.003). There were 21 patients who achieved actual 3-year survival; 20 received both anti-CTLA-4 and anti-PD-1, either sequentially or in combination. Over 80% of 3-year survivors with progressive disease were treated with local therapy after CPI.

CONCLUSIONS

Long survival in patients with metastatic melanoma from acral, mucosal, and uveal primary tumors was associated with receipt of both anti-CTLA-4 and anti-PD-1 antibodies. Complete responses were rare, and local therapy was frequently employed to control disease progression. While sun-shielded melanomas exhibit worse outcomes after CPI than cutaneous melanomas, with an aggressive multidisciplinary approach, 5-year survival is still possible for 25%-32% of these patients.

Normalization Cancer Immunotherapy for Melanoma

Today, we are witnessing a revolution in the treatment of cancer using immunotherapy. In the past decade, work from many laboratories and clinicians has unequivocally demonstrated that the immune system can eradicate established cancers and enhance patient survival. However, immunotherapies have distinct tumor response-to-toxicity profiles owing to distinct mechanisms of action. We have previously termed immunotherapies that activate a general systemic immune response as enhancement cancer immunotherapy and those that target a specific dysfunctional immune response, especially within the tumor microenvironment, as normalization cancer immunotherapy. In this perspective, we provide a framework for normalization cancer immunotherapy in the context of melanoma.

The Role of Immune Checkpoint Blockade in Uveal Melanoma

Uveal melanoma (UM) represents the most common intraocular malignancy in adults and accounts for about 5% of all melanomas. Primary disease can be effectively controlled by several local therapy options, but UM has a high potential for metastatic spread, especially to the liver. Despite its clinical and genetic heterogeneity, therapy of metastatic UM has largely been adopted from cutaneous melanoma (CM) with discouraging results until now. The introduction of antibodies targeting CTLA-4 and PD-1 for immune checkpoint blockade (ICB) has revolutionized the field of cancer therapy and has achieved pioneering results in metastatic CM. Thus, expectations were high that patients with metastatic UM would also benefit from these new therapy options. This review provides a comprehensive and up-to-date overview on the role of ICB in UM. We give a summary of UM biology, its clinical features, and how it differs from CM. The results of several studies that have been investigating ICB in metastatic UM are presented. We discuss possible reasons for the lack of efficacy of ICB in UM compared to CM, highlight the pitfalls of ICB in this cancer entity, and explain why other immune-modulating therapies could still be an option for future UM therapies.

T cell receptor-based cancer immunotherapy: Emerging efficacy and pathways of resistance

Adoptive cell transfer (ACT) using chimeric antigen receptor (CAR)-modified T cells can induce durable remissions in patients with refractory B-lymphoid cancers. By contrast, results applying CAR-modified T cells to solid malignancies have been comparatively modest. Alternative strategies to redirect T cell specificity and cytolytic function are therefore necessary if ACT is to serve a greater role in human cancer treatments. T cell receptors (TCRs) are antigen recognition structures physiologically expressed by all T cells that have complementary, and in some cases superior, properties to CARs. Unlike CARs, TCRs confer recognition to epitopes derived from proteins residing within any subcellular compartment, including the membrane, cytoplasm and nucleus. This enables TCRs to detect a broad universe of targets, such as neoantigens, cancer germline antigens, and viral oncoproteins. Moreover, because TCRs have evolved to efficiently detect and amplify antigenic signals, these receptors respond to epitope densities many fold smaller than required for CAR-signaling. Herein, we summarize recent clinical data demonstrating that TCR-based immunotherapies can mediate regression of solid malignancies, including immune-checkpoint inhibitor refractory cancers. These trials simultaneously highlight emerging mechanisms of TCR resistance. We conclude by discussing how TCR-based immunotherapies can achieve broader dissemination through innovations in cell manufacturing and non-viral genome integration techniques.

Key Factors in Clinical Protocols for Adoptive Cell Therapy in Melanoma

Adoptive cell therapy (ACT) with autologous tumor infiltrating lymphocytes (TIL) has been studied for patients with advanced metastatic cancers (primarily melanoma) for decades and has changed significantly during that period. Treatment with TIL includes ex vivo cell activation and expansion followed by re-infusion of these cells into the patient. After cell infusion, patients receive Interleukin-2 (IL-2). Objective response rates up to 52% have been seen in patients with metastatic melanoma. Efforts to improve TIL therapy include better selection and expansion of tumor-reactive lymphocytes, optimization of IL-2 or other T cell activating cytokine dosing, and, potentially, genetic manipulation of the immune cell product. Here we describe methods involved in the collection, expansion, and treatment with TIL for patients with metastatic melanoma.

lncRNA SNHG7 affects malignant tumor behaviors through downregulation of EZH2 in uveal melanoma cell lines

Previous studies have demonstrated that the long non-coding RNA, small nucleolar RNA host gene 7 (SNHG7) plays an important role in several types of cancer; however, its role in the development of uveal melanoma (UM) remains unclear. The present study investigated the effect of SNHG7 on the prognosis of UM, as well as on cell proliferation, cell cycle and apoptosis of UM cell lines. Furthermore, the present study aimed to determine the molecular mechanisms underlying these effects. The association between SNHG7 and prognosis of UM was analyzed using detailed SNHG7 mRNA expression data and clinical information from The Cancer Genome Atlas database. Reverse transcription-quantitative PCR was used in order to detect the differential expression of SNHG7 in UM tissues and cell lines. Cell proliferation was detected using Cell Counting Kit-8 assays, following overexpression of SNHG7. A cell cycle assay was performed using propidium iodide/RNase staining. An apoptosis assay was performed using the Annexin-V-Fluorescein isothiocyanate apoptosis detection kit. The expression of enhancer of zeste homolog 2 (EZH2) was measured via western blotting. The results of the present study indicated that low expression of SNHG7 was associated with poor prognosis. Furthermore, increasing the expression of SNHG7 inhibited the proliferation of UM cells, suppressed cell cycle progression and promoted apoptosis. Western blot analysis results revealed that overexpression of SNHG7 downregulated EZH2 protein expression levels in UM cell lines. The results of the present study demonstrated that SNHG7 inhibited malignant transformation of UM cells by regulating EZH2 expression.

Identification and ranking of recurrent neo-epitopes in cancer

Background

Immune escape is one of the hallmarks of cancer and several new treatment approaches attempt to modulate and restore the immune system’s capability to target cancer cells. At the heart of the immune recognition process lies antigen presentation from somatic mutations. These neo-epitopes are emerging as attractive targets for cancer immunotherapy and new strategies for rapid identification of relevant candidates have become a priority.

Methods

We carefully screen TCGA data sets for recurrent somatic amino acid exchanges and apply MHC class I binding predictions.

Results

We propose a method for in silico selection and prioritization of candidates which have a high potential for neo-antigen generation and are likely to appear in multiple patients. While the percentage of patients carrying a specific neo-epitope and HLA-type combination is relatively small, the sheer number of new patients leads to surprisingly high reoccurence numbers. We identify 769 epitopes which are expected to occur in 77629 patients per year.

Conclusion

While our candidate list will definitely contain false positives, the results provide an objective order for wet-lab testing of reusable neo-epitopes. Thus recurrent neo-epitopes may be suitable to supplement existing personalized T cell treatment approaches with precision treatment options.

Rare cause of spontaneous haemothorax: mediastinal and distant lymph node metastases from uveal melanoma

We report a rare case of isolated mediastinal and inferior mediastinal lymph node metastases from choroidal melanoma. The patient was treated for primary choroidal melanoma with local tumour resection and radioactive plaque brachytherapy. Eleven years later, he was diagnosed with metastatic disease. Molecular analysis of the metastatic tumour demonstrated a GNAQ Q209P mutation. There was no evidence of malignant blue naevus or primary melanoma of the central nervous system on physical examination or imaging. The rare modality of clinical presentation highlights the unpredictable nature of metastatic uveal melanoma.

Immunobiology of Uveal Melanoma: State of the Art and Therapeutic Targets

Uveal Melanoma (UM) represents the most common primary intraocular malignant tumor in adults. Although it originates from melanocytes as cutaneous melanoma, it shows significant clinical and biological differences with the latter, including high resistance to immune therapy. Indeed, UM can evade immune surveillance via multiple mechanisms, such as the expression of inhibitory checkpoints (e.g., PD-L1, CD47, CD200) and the production of IDO-1 and soluble FasL, among others. More in-depth understanding of these mechanisms will suggest potential targets for the design of novel and more effective management strategies for UM patients.

Randomized Phase II Trial and Tumor Mutational Spectrum Analysis from Cabozantinib versus Chemotherapy in Metastatic Uveal Melanoma (Alliance A091201)

PURPOSE

The surface receptor MET is highly expressed on primary uveal melanoma; MET inhibitors demonstrated early clinical signals of efficacy in slowing uveal melanoma growth. The primary objective of our study was to compare the progression-free survival rate at 4 months (PFS4) of patients with uveal melanoma treated with cabozantinib or chemotherapy.

PATIENTS AND METHODS

Patients with metastatic uveal melanoma and RECIST measurable disease were randomized 2:1 to receive either cabozantinib (arm 1) versus temozolomide or dacarbazine (arm 2) with restaging imaging every two cycles. Cross-over from arm 2 to cabozantinib after progression was allowed (arm 2X). Available tumor specimens were analyzed by whole-exome sequencing (WES) and results were correlated with outcome.

RESULTS

Forty-six eligible patients were accrued with 31, 15, and 9 in arms 1, 2, and 2X, respectively. Median lines of prior therapy, including hepatic embolization, were two. Rates of PFS4 in arm 1 and arm 2 were 32.3% and 26.7% (P = 0.35), respectively, with median PFS time of 60 and 59 days (P = 0.964; HR = 0.99). Median overall survival (OS) was 6.4 months and 7.3 months (P = 0.580; HR = 1.21), respectively. Grade 3-4 Common Terminology Criteria for Adverse Events were present in 61.3%, 46.7%, and 37.5% in arms 1, 2, and 2X, respectively. WES demonstrated a mean tumor mutational burden of 1.53 mutations/Mb and did not separate OS ≤ or >1 year (P = 0.14). Known mutations were identified by WES and novel mutations were nominated.

CONCLUSIONS

MET/VEGFR blockade with cabozantinib demonstrated no improvement in PFS but an increase in toxicity relative to temozolomide/dacarbazine in metastatic uveal melanoma.

Utilizing T-cell Activation Signals 1, 2, and 3 for Tumor-infiltrating Lymphocytes (TIL) Expansion: The Advantage Over the Sole Use of Interleukin-2 in Cutaneous and Uveal Melanoma

In this study, we address one of the major critiques for tumor-infiltrating lymphocyte (TIL) therapy-the time needed for proper expansion of a suitable product. We postulated that T-cell receptor activation in the first phase of expansion combined with an agonistic stimulation of CD137/4-1BB and interleukin-2 would favor preferential expansion of CD8 TIL. Indeed, this novel 3-signal approach for optimal T-cell activation resulted in faster and more consistent expansion of CD8CD3 TIL. This new method allowed for successful expansion of TIL from cutaneous and uveal melanoma tumors in 100% of the cultures in <3 weeks. Finally, providing the 3 signals attributed to optimal T-cell activation led to expansion of TIL capable of recognizing their tumor counterpart in cutaneous and uveal melanoma. This new methodology for the initial phase of TIL expansion brings a new opportunity for translation of TIL therapy in challenging malignancies such as uveal melanoma.

Chimeric antigen receptor T-cell therapy for cancer: a basic research-oriented perspective

Chimeric antigen receptor (CAR) T cells have outstanding therapeutic potential for treating blood cancers. The prospects for this technology have accelerated basic research, clinical translation and Big Pharma's investment in the field of T-cell therapeutics. This interest has led to the discovery of key factors that affect CAR T-cell efficacy and play pivotal roles in T-cell immunology. Herein, we introduce advances in adoptive immunotherapy and the birth of CAR T cells, and review CAR T-cell studies that focus on three important features: CAR constructs, target antigens and T-cell phenotypes. At last, we highlight novel strategies that overcome the tumor microenvironment and circumvent CAR T-cell side effects, and consider the future direction of CAR T-cell development.

Immunological Backbone of Uveal Melanoma: Is There a Rationale for Immunotherapy?

No standard treatment has been established for metastatic uveal melanoma (mUM). Immunotherapy is commonly used for this disease even though UM has not been included in phase III clinical trials with checkpoint inhibitors. Unfortunately, only a minority of patients obtain a clinical benefit with immunotherapy. The immunological features of mUM were reviewed in order to understand if immunotherapy could still play a role for this disease.

Synergic Interactions Between Hepatic Stellate Cells and Uveal Melanoma in Metastatic Growth

Uveal melanoma (UM) is a malignant intraocular tumor that spreads to the liver in half of the cases. Since hepatic cells could play a role in the therapeutic resistance of metastatic UM, the purpose of our study was to investigate the pro-invasive role of hepatic stellate cells (HSteCs) in metastatic UM at the micro- and macro-metastatic stages. We first performed an immunostaining with the alpha-smooth muscle actin (αSMA) to localize activated HSteCs in UM liver macro-metastases from four patients. Their accumulation of collagen was assessed with Masson’s Trichrome stain. Next, we inoculated metastatic UM cells alone or with human HSteCs in triple-immunodeficient mice, in order to determine if HSteCs are recruited as early as the micro-metastatic stage. The growth of metastatic foci was imaged in the liver by ex vivo fluorescence imaging. Histological analyses were performed with Masson’s Trichrome and Picrosirius Red stains, and antibodies against Melan-A and αSMA. The collagen content was measured in xenografts by quantitative polarization microscopy. In patient hepatectomy samples, activated HSteCs and their pathological matrix were localized surrounding the malignant lesions. In the mouse xenograft model, the number of hepatic metastases was increased when human HSteCs were co-inoculated. Histological analyses revealed a significant recruitment of HSteCs near the micro/macrolesions, and an increase in fibrillar collagen production. Our results show that HSteCs can provide a permissive microenvironment and might increase the therapeutic resistance of metastatic UM.

Immunotherapies for the Treatment of Uveal Melanoma-History and Future

Background: Uveal melanoma is the most common primary intraocular malignancy among adults. It is, nevertheless, a rare disease, with an incidence of approximately one case per 100,000 individuals per year in Europe. Approximately half of tumors will eventually metastasize, and the liver is the organ usually affected. No standard-of-care treatment exists for metastasized uveal melanoma. Chemotherapies or liver-directed treatments do not usually result in long-term tumor control. Immunotherapies are currently the most promising therapy option available. Methods: We reviewed both relevant recent literature on PubMed concerning the treatment of uveal melanoma with immunotherapies, and currently investigated drugs on ClinicalTrials.gov. Our own experiences with immune checkpoint blockers are included in a case series of 20 patients. Results: Because few clinical trials have been conducted for metastasized uveal melanoma, no definitive treatment strategy exists for this rare disease. The outcomes of most immunotherapies are poor, especially compared with cutaneous melanoma. However, encouraging results have been found for some very recently investigated agents such as the bispecific tebentafusp, for which a remarkably increased one-year overall survival rate, and similarly increased disease control rate, were observed in early phase studies. Conclusions: The treatment of metastatic uveal melanoma remains challenging, and almost all patients still die from the disease. Long-term responses might be achievable by means of new immunological strategies. Patients should therefore be referred to large medical centers where they can take part in controlled clinical studies.

Tebentafusp: T Cell Redirection for the Treatment of Metastatic Uveal Melanoma

Metastatic disease from uveal melanoma occurs in almost 50% of patients suffering from this ocular tumour, with median survival from development of symptoms being around 1 year. In contrast to cutaneous melanoma, kinase inhibitors and immune checkpoint inhibitors are usually ineffective in patients with metastatic uveal melanoma. Tebentafusp is a novel form of immunotherapy based on the immune-mobilising monoclonal T cell receptor against cancer (ImmTAC) platform, which comprises a soluble T cell receptor that is fused to an anti-CD3 single-chain variable fragment. The T cell receptor domain of tebentafusp targets cells present a human leukocyte antigen-A*02:01 complexed with a peptide derived from the melanoma-associated antigen gp100, which is expressed strongly by melanoma cells, weakly by normal melanocytes and minimally by other tissues. The anti-CD3 domain recruits CD3+ T cells (and, indirectly, other immune cells), redirecting these to the melanoma cells. The most common adverse events with tebentafusp are manageable and usually transient. Early survival data in patients with metastatic uveal melanoma are promising when considered alongside historical data. Based on these encouraging results, a randomised study comparing tebentafusp to investigator’s choice of therapy in metastatic uveal melanoma is ongoing.

Targeting Immune-Mediated Dormancy: A Promising Treatment of Cancer

Immune-mediated dormancy is when the immune system keeps proliferating tumor cells unchanged, mostly via cytotoxic activity of immune cells. Cancer dormancy, especially immune-mediated dormancy, may be the explanation for tumor refractory and may be responsible for resistance to conventional chemo- and radiotherapies. Here, we will describe different scenarios as to how the immune cells and cytokines involved in cancer progression are connected with the initiation of dormancy and cancer treatment. Two distinct treatment methods, such as maintaining metastatic tumor cells dormant and awakening them, are also discussed. A better understanding of immune-mediated dormancy will help to design novel and effective immunotherapies and will likely increase the efficiency of tumor treatment inhibiting metastasis.

Uveal Versus Cutaneous Melanoma; Same Origin, Very Distinct Tumor Types

Here, we critically evaluated the knowledge on cutaneous melanoma (CM) and uveal melanoma (UM). Both cancer types derive from melanocytes that share the same embryonic origin and display the same cellular function. Despite their common origin, both CM and UM display extreme differences in their genetic alterations and biological behavior. We discuss the differences in genetic alterations, metastatic routes, tumor biology, and tumor-host interactions in the context of their clinical responses to targeted- and immunotherapy.

[What's new in oncodermatology?]

This year again, several breaking news were published in our field of oncodermatology, especially in the domain of immunotherapy. Many works have reported results on predictive biomarker identification. Concerning melanoma treatment, we were disappointed by the negative results of the phase III trial evaluating the IDO1 inhibitor epacadostat + pembrolizumab versus pembrolizumab. However, many promising preliminary results involving the combinations of anti-PD1 and innate immunity activators have been published. We also have a new anti-BRAF + anti-MEK combination: encorafenib + binimetinib with a good benefit/risk ratio and a particularly favorable safety profile as compared with existing similar combinations. Major steps forward were obtained for locally advanced Merkel cell carcinoma and squamous cell carcinoma with anti-PDL-1 avelumab and anti-PD1 cemiplimab respectively.