Clinical and molecular response to tebentafusp in previously treated patients with metastatic uveal melanoma: a phase 2 trial

Meeting Report From the 2023 Cure Ocular Melanoma (CURE OM) Global Science Meeting, Philadelphia, PA, November 2023

The 2023 Cure Ocular Melanoma (CURE OM) Global Science Meeting was held in Philadelphia on November 6, 2023. There is increased awareness and dedicated research in uveal melanoma (UM), but unmet needs remain in the prevention, detection, and treatment of UM. The purpose of this meeting was to provide an international forum for the exchange of research ideas, to allow for discussion of basic science as well as clinical research on UM, and to gather input about advocacy and patient needs.

Treatment sequence with tebentafusp and immune checkpoint inhibitors in patients with metastatic uveal melanoma and metastatic GNA11/GNAQ mutant melanocytic tumors

BACKGROUND

Metastatic uveal melanoma (mUM) is rare. Immune checkpoint inhibitors (ICIs) have shown modest efficacy in mUM. Tebentafusp prolonged overall survival (OS) in a phase 3 study. We aimed to investigate the efficacy and safety of the sequence of tebentafusp and ICIs.

METHODS

Patients with HLA-A * 02:01 positive mUM, or metastatic GNA11/GNAQ mutant melanocytic tumors treated with tebentafusp followed by ICIs (group 1) or the inverse sequence (group 2) at any treatment line were retrospectively identified. The primary objective was OS rate at 2 years.

RESULTS

131 patients were included; 51 in group 1 and 80 in group 2. 30 % in group 1 % and 40 % in group 2 had normal baseline lactate dehydrogenase (LDH, p = 0.05). 94 % in group 1 % and 77 % in group 2 had multilobular liver disease (p = 0.02). Median OS was 22.4 months (95 % CI 19-24.8) in group 1 and 33.6 months (95 % CI 28.9-43) in group 2 (p = 0.004). Total median PFS was 12 months (95 % CI 10.7-18.8) in group 1 and 20.3 months (95 % CI 17.2-27.3) in group 2 (p = 0.04). The frequency of cytokine release syndrome was higher in group 2 (15 % vs 27 %). Other clinical factors were associated with short total PFS in the multivariable analysis.

CONCLUSIONS

Both treatment sequences are clinically feasible. A clinical benefit was noted in the sequential combination of ICIs followed by tebentafusp. This observation is limited by the retrospective nature of the study and merits further investigation in prospective clinical trials.

Efficacy and safety of tebentafusp in patients with metastatic uveal melanoma: A systematic review and meta-analysis

Patients with metastatic uveal melanoma (mUM) have a poor prognosis, and few appropriate medications are available. Tebentafusp is approved by the Food and Drug Administration for mUM recently. However, the real efficacy and safety of tebentafusp are still unclear. We searched PubMed, Embase, and Cochrane Library from inception to March 20, 2024. The research was reported based on the preferred reporting items for systematic reviews and meta-analysis guidelines. We used random effects models to aggregate data on the response rates and adverse events of tebentafusp therapy. Six studies met the inclusion criteria with a total sample of 589 participants. The pooled objective response rate was 0.08 (95% CI: 0.05-0.12), and pooled disease control rate was 0.51 (95% CI: 0.44-0.57). The overall incidence was 0.99 (95% CI: 0.95-1.00) for any grade adverse events, 0.50 (95% CI: 0.41-0.59) for grade 3-4 adverse events, and 0.01 (95% CI: 0-0.03) for discontinuation due to adverse events. Tebentafusp exhibits promising treatment outcomes for mUM patients. Although accompanied with a common occurrence of adverse events, which can typically be managed and controlled. Future research is necessary for substantiating these findings and refining guidelines for management of mUM.

Efficacy and Tolerability of Tebentafusp in Metastatic Uveal Melanoma: A Real-life Retrospective Multicentre Study

Metastatic uveal melanoma is a rare disease with a poor prognosis. Usual treatments have not proven effective. Tebentafusp, a bispecific protein targeting melanoma cells and T lymphocytes, is the first approved treatment with a proven survival benefit in a randomized clinical. Our purpose was to evaluate tebentafusp's real-life efficacy and tolerability for metastatic uveal melanoma. This retrospective study included patients from 14 French centres. Twenty-three patients were included. One-year survival was 66%; median progression-free survival was 5.7 months. Objective response rate was 23% and best overall response was complete remission for 4% of patients; partial remission for 18%, stable disease for 41%, and progressive disease for 36%. The most frequent adverse events were fever, chills, pruritus, and rash; 30% experienced severe adverse events. No death or treatment discontinuation was linked to adverse events. These data showed better overall survival with tebentafusp than that reported in historical cohorts.

The role of circulating tumor DNA in melanomas of the uveal tract

Melanoma of the uveal tract or uveal melanoma (UM) originates from melanocytes of the eye and is the most common intraocular malignancy in adults. Despite considerable advances in diagnostic procedures and treatments, prognosis remains poor in those with advanced disease. Accordingly, although current treatments have an excellent local disease control rate, approximately 50% of patients develop metastatic relapse within 10 years. The high risk for metastatic disease with a variable and often long latency period is thought to be due to early spread of cancer cells disseminating into organs such as the liver, followed by a period of dormancy, before the eventual emergence of radiologically measurable disease. Early detection of disease relapse or metastasis is therefore crucial to allow timely treatment and ultimately improve patient outcome. Recently, advances in minimally-invasive liquid biopsy techniques and biomarkers such as circulating tumor DNA (ctDNA) have demonstrated potential to transform the field of cancer care by aiding diagnosis, prognosis and monitoring of various cancer types. UM is particularly suitable for ctDNA-based approaches due to the relatively well-characterized spectrum of genetic mutations, along with the inherent difficulties and risks associated with getting sufficient tumor samples via traditional biopsy methods. Key potential advantage of ctDNA are the detection of molecular residual disease (MRD) in patients post definitive treatment, and in the early identification of metastasis. This is particularly relevant contemporarily with the recent demonstration of tebentafusp improving survival in metastatic UM patients, and opens avenues for further research to investigate the potential utilization of tebentafusp combined with ctDNA-based strategies in adjuvant settings and early intervention for MRD. The present review illustrates the current understanding of ctDNA-based strategies in UM, discusses the potential clinical applications, explores the potential of utilizing ctDNA in UM MRD in the context of an ongoing clinical trial, and highlights the challenges that need to be overcome prior to routine clinical implementation.

Engineering T-cell receptor-like antibodies for biologics and cell therapy

A major prevailing challenge limiting our ability to fully harness the potential of the latest-generation therapeutic antibodies is the scarcity of clinically established disease-specific targets. A major next step forward will therefore be to expand this target space. The recent clinical success of immunotherapies such as adoptive T-cell transfer, immune checkpoint inhibition, and chimeric antigen receptor (CAR) T-cell therapy strongly supports focusing on the immunopeptidome of peptides presented by human leukocyte antigen (pHLA) that are normally surveilled by T-cell receptors (TCRs). Directing novel antibody development toward pHLA targets has given rise to TCR-like antibodies, which reached the clinic in 2020, as both bispecific T-cell engaging antibodies and the CARs of CAR-T cell therapies. In this review, we highlight recent advances in TCR-like antibodies, including therapeutic modalities, engineering strategies, and benchmarks for success.

Imipridones inhibit tumor growth and improve survival in an orthotopic liver metastasis mouse model of human uveal melanoma

BACKGROUND

Uveal melanoma (UM) is a highly aggressive disease with very few treatment options. We previously demonstrated that mUM is characterized by high oxidative phosphorylation (OXPHOS). Here we tested the anti-tumor, signaling and metabolic effects of imipridones, which are CLPP activators, which inhibit OXPHOS indirectly and have demonstrated safety in patients.

METHODS

We assessed CLPP expression in UM patient samples. We tested the effects of imipridones (ONC201 and ONC212) on the growth, survival, signaling and metabolism of UM cell lines in vitro, and for therapeutic efficacy in vivo in UM liver metastasis models.

RESULTS

CLPP expression was detected in primary and mUM patient samples. ONC201 and 212 decreased OXPHOS effectors, inhibited cell growth and migration, and induced apoptosis in human UM cell lines in vitro. ONC212 inhibited OXPHOS, increased metabolic stress and apoptotic pathways, inhibited amino acid metabolism, and induced cell death-related lipids. ONC212 also decreased tumor burden and increased survival in vivo in two UM liver metastasis models.

CONCLUSIONS

Imipridones are a promising strategy for further testing and development in mUM.

Logic-gated and contextual control of immunotherapy for solid tumors: contrasting multi-specific T cell engagers and CAR-T cell therapies

CAR-T cell and T cell engager therapies have demonstrated transformational efficacy against hematological malignancies, but achieving efficacy in solid tumors has been more challenging, in large part because of on-target/off-tumor toxicities and sub-optimal T cell anti-tumor cytotoxic functions. Here, we discuss engineering solutions that exploit biological properties of solid tumors to overcome these challenges. Using logic gates as a framework, we categorize the numerous approaches that leverage two inputs instead of one to achieve better cancer selectivity or efficacy in solid tumors with dual-input CAR-Ts or multi-specific TCEs. In addition to the "OR gate" and "AND gate" approaches that leverage dual tumor antigen targeting, we also review "contextual AND gate" technologies whereby continuous cancer-selective inputs such a pH, hypoxia, target density, tumor proteases, and immune-suppressive cytokine gradients can be creatively incorporated in therapy designs. We also introduce the notion of "output directionality" to distinguish dual-input strategies that mechanistically impact cancer cell killing or T cell fitness. Finally, we contrast the feasibility and potential benefits of the various approaches using CAR-T and TCE therapeutics and discuss why the promising "IF/THEN" and "NOT" gate types pertain more specifically to CAR-T therapies, but can also succeed by integrating both technologies.

High-affinity T cell receptor ImmTAC® bispecific efficiently redirects T cells to kill tumor cells expressing the cancer-testis antigen PRAME

Background

PRAME (Preferentially expressed Antigen in Melanoma) is a cancer-testis antigen expressed in several tumor indications, representing an attractive anticancer target. However, its intracellular location limits targeting by traditional methods. PRAME peptides are presented on the surface of tumor cells by human leukocyte antigen (HLA) molecules, indicating that a T cell receptor (TCR)-based strategy that redirects T cells to kill PRAME+ tumors could be a novel immunotherapeutic option. We confirm that PRAME protein is expressed in cutaneous melanoma, including rare subtypes with limited treatment options, as well as primary and metastatic lung, breast, endometrial, and ovarian tumors. Furthermore, PRAME is expressed homogeneously across tumors with distinct oncogenic mutations, mutation burden, PD-L1 expression, immune infiltration, and features of immune checkpoint resistance. Immunopeptidomic analysis of primary tumors detected HLA class I-restricted PRAME peptides.

Methods

A TCR recognizing PRAME peptide SLLQHLIGL was engineered to high affinity and fused to a CD3 engaging domain to create a TCRxCD3 bispecific molecule (Immune-mobilizing monoclonal TCR Against Cancer, ImmTAC®) with the ability to redirect polyclonal T cells to efficiently kill PRAME+ cells.

Rs

The degree of T cell activation was positively correlated with peptide-HLA abundance, with as few as 10 epitopes per cell sufficient for target cell killing. Impaired ImmTAC®-redirected cytotoxicity of exhausted T cells was rescued using an anti-PD-1 antibody, supporting the use of a combination strategy to treat tumors with active PDL1-PD1 axes.

Conclusions

Our data demonstrate selective and efficient T cell activation and killing by a PRAME-directed TCRxCD3 bispecific, supporting further investigation in multiple cancer indications.

Survival Distinctions for Cases Representing Immunologically Cold Tumors via Intrinsic Disorder Assessments for Blood-Sourced TRB Variable Regions

T cell receptor beta (TRB) sequences were recovered from the Cancer Genome Atlas Uveal Melanoma blood exome files. Intrinsic disorder scores for amino acid (AA) sequences of the entire TRB variable region were obtained and evaluated as potentially representative of overall survival (OS) distinctions, i.e., for cases representing the upper and lower 50th percentiles for intrinsic disorder scores. Analyses using four intrinsic disorder assessment tools indicated that a lower intrinsic disorder of the blood-sourced TRB variable regions, including continuous AA sequences of the V-gene segment, the complementarity-determining region-3, and the J-gene segment, was associated with a better OS probability (with log-rank p-values ranging from 0.002 to 0.014). We further determined that intrinsic disorder assessments could be used for OS stratification for a second, immunologically cold cancer: MYCN amplified neuroblastoma. Thus, intrinsic disorder assessments of blood-sourced, full TRB variable regions may provide a novel patient stratification approach for patients with immunologically cold cancers.

Prospective assessment of circulating tumor DNA in patients with metastatic uveal melanoma treated with tebentafusp

Tebentafusp, a bispecific immune therapy, is the only drug that demonstrated an overall survival benefit in patients with metastatic uveal melanoma (MUM). Circulating tumor DNA (ctDNA) has emerged as a potential prognostic and predictive marker in the phase 3 IMCgp100-202 trial using multiplex PCR-based next-generation sequencing (NGS). In this study (NCT02866149), ctDNA dynamics were assessed using droplet digital PCR (ddPCR) in 69 MUM patients undergoing tebentafusp treatment. Notably, 61% of patients exhibited detectable ctDNA before treatment initiation, which was associated with shorter overall survival (median 12.9 months versus 40.5 months for patients with undetectable ctDNA; p < 0.001). Patients manifesting a 90% or greater reduction in ctDNA levels at 12 weeks demonstrated markedly prolonged overall survival (median 21.2 months versus 12.9 months; p = 0.02). Our findings highlight the potential of ddPCR-based ctDNA monitoring as an economical, pragmatic and informative approach in MUM management, offering valuable insights into treatment response and prognosis.

Liquid Biopsy in Pancreatic Ductal Adenocarcinoma: A Review of Methods and Applications

Pancreatic ductal adenocarcinoma (PDAC) remains a malignancy with one of the highest mortality rates. One limitation in the diagnosis and treatment of PDAC is the lack of an early and universal biomarker. Extensive research performed recently to develop new assays which could fit this role is available. In this review, we will discuss the current landscape of liquid biopsy in patients with PDAC. Specifically, we will review the various methods of liquid biopsy, focusing on circulating tumor DNA (ctDNA) and exosomes and future opportunities for improvement using artificial intelligence or machine learning to analyze results from a multi-omic approach. We will also consider applications which have been evaluated, including the utility of liquid biopsy for screening and staging patients at diagnosis as well as before and after surgery. We will also examine the potential for liquid biopsy to monitor patient treatment response in the setting of clinical trial development.

Immunotherapy response and resistance in patients with advanced uveal melanoma: a retrospective cohort study

Metastatic uveal melanoma (mUM) is associated with poor prognosis. Ipilimumab/nivolumab has shown antitumor efficacy in phase II studies. Tebentafusp resulted in longer overall survival (OS) compared to investigator`s choice in a phase III study. We sought to describe the radiological response patterns of mUM patients treated with immunotherapy. Patients with mUM treated with ipilimumab/nivolumab and tebentafusp between July 2018 and December 2022, with available radiological assessment per RECISTv1.1 and/or imPERCIST5, were retrospectively identified and included. Progression-free survival (PFS) and OS rates, liver-specific response and pathological assessment in available liver biopsies were evaluated. In the ipilimumab/nivolumab group, median PFS (mPFS) was 2.9 months (95% CI 2.2-28.6) and mOS 28.9 months (95% CI 12.7-NR). Complete (CMR) and partial (PMR) metabolic response per imPERCIST5, and partial response (PR) per RECISTv1.1 were associated with longer PFS and OS by trend, compared to morphologically and metabolically stable or progressive disease. In the tebentafusp group, mPFS was 2.7 months (95% CI 2.2-3) and mOS 18.6 months (95% CI 11.5-NR). PMR and PR were associated with longer PFS by trend. In both treatments, the overall treatment response was associated with the radiological response at the liver site. In available liver tumor biopsies, differences in pathological and radiological responses were noted. ImPERCIST5 and RECIST v1.1 are valuable tools in the radiological response assessment, but both methods display limitations. Accurate biomarkers to stratify patients at risk for disease progression and future translational studies to investigate mechanisms of response and resistance are required.

15-Gene Expression Profile and PRAME as Integrated Prognostic Test for Uveal Melanoma: First Report of Collaborative Ocular Oncology Group Study No. 2 (COOG2.1)

PURPOSEValidated and accurate prognostic testing is critical for precision medicine in uveal melanoma (UM). Our aims were to (1) prospectively validate an integrated prognostic classifier combining a 15-gene expression profile (15-GEP) and PRAME RNA expression and (2) identify clinical variables that enhance the prognostic accuracy of the 15-GEP/PRAME classifier.MATERIALS AND METHODSThis study included 1,577 patients with UM of the choroid and/or ciliary body who were enrolled in the Collaborative Ocular Oncology Group Study Number 2 (COOG2) and prospectively monitored across 26 North American centers. Test results for 15-GEP (class 1 or class 2) and PRAME expression status (negative or positive) were available for all patients. The primary end point was metastasis-free survival (MFS).RESULTS15-GEP was class 1 in 1,082 (68.6%) and class 2 in 495 (31.4%) patients. PRAME status was negative in 1,106 (70.1%) and positive in 471 (29.9%) patients. Five-year MFS was 95.6% (95% CI, 93.9 to 97.4) for class 1/PRAME(-), 80.6% (95% CI, 73.9 to 87.9) for class 1/PRAME(+), 58.3% (95% CI, 51.1 to 66.4) for class 2/PRAME(-), and 44.8% (95% CI, 37.9 to 52.8) for class 2/PRAME(+). By multivariable Cox proportional hazards analysis, 15-GEP was the most important independent predictor of MFS (hazard ratio [HR], 5.95 [95% CI, 4.43 to 7.99]; P < .001), followed by PRAME status (HR, 1.82 [95% CI, 1.42 to 2.33]; P < .001). The only clinical variable demonstrating additional prognostic value was tumor diameter.CONCLUSIONIn the largest prospective multicenter prognostic biomarker study performed to date in UM to our knowledge, the COOG2 study validated the superior prognostic accuracy of the integrated 15-GEP/PRAME classifier over 15-GEP alone and clinical prognostic variables. Tumor diameter was found to be the only clinical variable to provide additional prognostic information. This prognostic classifier provides an advanced resource for risk-adjusted metastatic surveillance and adjuvant trial stratification in patients with UM.

Recent Advancements in Cell-Based Therapies in Melanoma

Malignant melanoma outcomes have drastically changed in recent years due to the introduction of immune checkpoint inhibitors (ICIs). However, many patients still experience intolerable side effects, therapy resistance, and disease progression on ICI therapy. Therefore, there remains a need for novel therapeutics that address this gap in treatment options. Cell-based therapies have gained wide attention as a therapeutic option that could address this gap in treatment options for advanced melanoma. These therapies work by extracting certain cell types produced in the human body such as T-cells, modifying them based on a specific target, and transfusing them back into the patient. In the realm of cancer therapy, cell-based therapies utilize immune cells to target tumor cells while sparing healthy cells. Recently, the Food and Drug Administration (FDA) has approved the usage of lifileucel, a tumor-infiltrating lymphocyte (TIL) therapy, in advanced melanoma. This came following recent results from the C-144-01 study (NCT02360579), which demonstrated the efficacy and safety of TILs in metastatic melanoma patients who otherwise failed on standard ICI/targeted therapy. Thus, the results of this trial as well as the recent FDA approval have proven the viability of utilizing cell-based therapies to fill the gap in treatment options for patients with advanced melanoma. This review aims to provide a comprehensive overview of major cell-based therapies that have been utilized in melanoma by delineating results of the most recent multi-center phase II/ III clinical trials that evaluate the efficacy and safety of major cell-based therapies in melanoma. Additionally, we provide a summary of current limitations in each cell-based therapeutic option as well as a future direction of how to further extrapolate these cell-based therapies in advanced melanoma.

Optimizing ctDNA: An Updated Review of a Promising Clinical Tool for the Management of Uveal Melanoma

Uveal melanoma (UM) is the most common primary malignant intraocular tumor in adults. Distant metastasis is common, affecting around 50% of patients. Prognostic accuracy relies on molecular characterization of tumor tissue. In these patients, however, conventional biopsy can be challenging due to the difficulty of obtaining sufficient tissue for the analysis due to the small tumor size and/or post-brachytherapy shrinkage. An alternative approach is liquid biopsy, a non-invasive technique that allows for real-time monitoring of tumor dynamics. Liquid biopsy plays an increasingly prominent role in precision medicine, providing valuable information on the molecular profile of the tumor and treatment response. Liquid biopsy can facilitate early detection and can be used to monitor progression and recurrence. ctDNA-based tests are particularly promising due to their ease of integration into clinical practice. In this review, we discuss the application of ctDNA in liquid biopsies for UM. More specifically, we explore the emerging technologies in this field and the advantages and disadvantages of using different bodily fluids for liquid biopsy. Finally, we discuss the current barriers to routine clinical use of this technique.

The Current State of Systemic Therapy of Metastatic Uveal Melanoma

Uveal melanoma (UM) is genetically a distinct tumor compared to cutaneous melanoma (CM), and due to its low mutational burden, it is far less perceptible to the immune system. Thus, treatments that have revolutionized the treatment of CM remain widely inefficient in metastatic UM or only demonstrate effectiveness in a small subpopulation of patients. To this end, the therapeutic benefit of immune checkpoint blockade is very limited and may come at the expense of severe immune-related adverse events that could potentially affect all organ systems. Notably, tebentafusp, an entirely novel class of anti-cancer drugs, has received official authorization for the treatment of metastatic UM. It is the first agent that demonstrated a survival advantage in a randomized controlled trial of metastatic UM patients. Despite the survival benefit and approval, the restriction of tebentafusp to HLA-A*02:01-positive patients and the low objective response rate indicate the persistent need for additional therapies. Thus, liver-directed therapies are commonly used for tumor control of hepatic metastases and represent a central pillar of the daily management of liver-dominant disease. Further, promising data from targeted therapies independent of MEK-inhibitors, such as the combination of darovasertib and crizotinib, raise hope for additional options in metastatic UM in the future. This narrative review provides a timely and comprehensive overview of the current treatment landscape for metastatic UM.

T Cell-Engaging Bispecific Antibodies Targeting gp100 and PRAME: Expanding Application from Uveal Melanoma to Cutaneous Melanoma

Uveal melanoma represents a rare and aggressive subtype of melanoma with limited treatment options and poor prognosis, especially in the metastatic setting. Tebentafusp, a bispecific fusion protein, offers a promising therapeutic approach by targeting gp100, an antigen highly expressed in uveal melanoma cells, and redirecting T cell-mediated cytotoxicity towards tumor cells. This review provides an overview of the preclinical and clinical data on tebentafusp in the management of metastatic uveal melanoma. We summarize the mechanism of action, clinical efficacy, safety profile, and ongoing research efforts surrounding this innovative immunotherapy. Preclinical studies have demonstrated the ability of tebentafusp to induce potent and specific anti-tumor immune responses against gp100-expressing uveal melanoma cells. Clinical trials have shown encouraging results, with tebentafusp exhibiting meaningful clinical activity in a subset of patients with metastatic uveal melanoma. Importantly, tebentafusp has also demonstrated a manageable safety profile. By specifically targeting tumor cells expressing gp100, tebentafusp offers a promising therapeutic avenue for individuals with metastatic uveal melanoma, meeting a significant clinical need in this context. Continued clinical trials will provide additional insights into the impact of tebentafusp on treatment-resistant metastatic cutaneous melanoma. Furthermore, we are exploring the potential of T cell engagers directed against the cancer testis antigen PRAME, which could have widespread utility in the treatment of cutaneous melanoma as well as other PRAME-expressing malignancies.

Chimeric Antigen Receptor T Cell with an Inducible Caspase-9 Suicide Gene Eradicates Uveal Melanoma Liver Metastases via B7-H3 Targeting

PURPOSE

Uveal melanoma (UM) is the most common intraocular malignant tumor. Despite successful treatment of the primary tumor, about 50% of patients will recur with systemic diseases for which there are no effective treatment strategies. Here we investigated the preclinical efficacy of a chimeric antigen receptor (CAR) T-cell-based immunotherapy targeting B7-H3.

EXPERIMENTAL DESIGN

B7-H3 expression on primary and metastatic human UM samples and cell lines was assessed by RNA sequencing, flow cytometry, and immunohistochemistry. Antitumor activity of CAR T cells targeting B7-H3 was tested in vitro with UM cell lines, patient-derived organotypic tumor spheroids from patients with metastatic UM, and in immunodeficient and humanized murine models.

RESULTS

B7-H3 is expressed at high levels in >95% UM tumor cells in vitro and in vivo. We generated a B7-H3 CAR with an inducible caspase-9 (iCas9) suicide gene controlled by the chemical inducer of dimerization AP1903, which effectively kills UM cells in vitro and eradicates UM liver metastases in murine models. Delivery of iCas9.B7-H3 CAR T cells in experimental models of UM liver metastases demonstrates a durable antitumor response, even upon tumor rechallenge or in the presence of a significant metastatic disease burden. We demonstrate effective iCas9.B7-H3 CAR T-cell elimination in vitro and in vivo in response to AP1903. Our studies demonstrate more effective tumor suppression with iCas9.B7-H3 CAR T cells as compared to a B7-H3-targeted humanized monoclonal antibody.

CONCLUSIONS

These studies support a phase I clinical trial with iCas9.B7-H3 CAR T cells to treat patients with metastatic UM.

Recent advances in immunotherapy and its combination therapies for advanced melanoma: a review

The incidence of melanoma is increasing year by year and is highly malignant, with a poor prognosis. Its treatment has always attracted much attention. Among the more clinically applied immunotherapies are immune checkpoint inhibitors, bispecific antibodies, cancer vaccines, adoptive cell transfer therapy, and oncolytic virotherapy. With the continuous development of technology and trials, in addition to immune monotherapy, combinations of immunotherapy and radiotherapy have shown surprising efficacy. In this article, we review the research progress of immune monotherapy and combination therapy for advanced melanoma, with the aim of providing new ideas for the treatment strategy for advanced melanoma.

Recent Advances in Molecular and Genetic Research on Uveal Melanoma

Uveal melanoma (UM), a distinct subtype of melanoma, presents unique challenges in its clinical management due to its complex molecular landscape and tendency for liver metastasis. This review highlights recent advancements in understanding the molecular pathogenesis, genetic alterations, and immune microenvironment of UM, with a focus on pivotal genes, such as GNAQ/11, BAP1, and CYSLTR2, and delves into the distinctive genetic and chromosomal classifications of UM, emphasizing the role of mutations and chromosomal rearrangements in disease progression and metastatic risk. Novel diagnostic biomarkers, including circulating tumor cells, DNA and extracellular vesicles, are discussed, offering potential non-invasive approaches for early detection and monitoring. It also explores emerging prognostic markers and their implications for patient stratification and personalized treatment strategies. Therapeutic approaches, including histone deacetylase inhibitors, MAPK pathway inhibitors, and emerging trends and concepts like CAR T-cell therapy, are evaluated for their efficacy in UM treatment. This review identifies challenges in UM research, such as the limited treatment options for metastatic UM and the need for improved prognostic tools, and suggests future directions, including the discovery of novel therapeutic targets, immunotherapeutic strategies, and advanced drug delivery systems. The review concludes by emphasizing the importance of continued research and innovation in addressing the unique challenges of UM to improve patient outcomes and develop more effective treatment strategies.

Long-term survival follow-up for tebentafusp in previously treated metastatic uveal melanoma

BACKGROUND

Tebentafusp, a bispecific (gp100×CD3) ImmTAC, significantly improved overall survival (OS) outcomes for HLA-A*02:01+ adult patients with untreated metastatic uveal melanoma (mUM) and showed promising survival in previously treated mUM with 1-year OS of 62% in the primary analysis of study IMCgp100-102. Here we report long-term outcomes from this phase 1/2 study in pretreated mUM.

PATIENTS AND METHODS

Patients with previously treated mUM received tebentafusp weekly intravenous at 20 µg dose 1, 30 µg dose 2 and either 54, 64, 68, or 73 µg (phase 1) or 68 µg (phase 2) dose 3+. The primary objective was overall response rate. Secondary objectives included OS and safety. OS was estimated by Kaplan-Meier methods. Association between OS and baseline covariates, on-treatment Response Evaluation Criteria in Solid Tumors (RECIST) response, baseline tumor biopsy and circulating-tumor DNA (ctDNA) changes were assessed.

RESULTS

146 patients were treated with tebentafusp: 19 in phase 1 and 127 in phase 2. With a median follow-up duration of 48.5 months, the median OS was 17.4 months (95% CI, 13.1 to 22.8), and the 1-year, 2-year, 3-year and 4-year OS rates were 62%, 40%, 23% and 14%, respectively. Improved survival was associated with lower ctDNA baseline levels and greater ctDNA reductions by week 9 on-treatment, with 100% 1-year, 73% 2-year and 45% 3-year OS rates for patients with ctDNA clearance. Baseline gp100 expression was not associated with survival, despite more RECIST responses among patients with higher expression. No new safety signals were reported with long-term dosing.

CONCLUSIONS

This study represents the longest follow-up of a Tcell receptor bispecific to date and confirms the durable survival benefits achieved with tebentafusp in previously treated mUM with good tolerability long-term. A role for ctDNA reduction as an early indicator of clinical benefit was again suggested for patients treated with tebentafusp.

Clearance of plasma cell free DNA in metastatic uveal melanoma with radiographic response to immune checkpoint inhibitors

Purpose

To report a case of metastatic uveal melanoma treated with immune checkpoint inhibition in which serial circulating tumor DNA (ctDNA) was assessed throughout treatment.

Observations

A 33-year-old man was diagnosed with metastatic uveal melanoma and initially had progression of disease following hepatic embolization and nivolumab/ipilimumab. At the time, plasma ctDNA GNA11 and SF3B1 were measurable and repeat ctDNA showed increased variant allele frequency following further progression of disease on vorinostat. Following additional nivolumab/ipilimumab, radiographic response was noted and repeat ctDNA became undetectable and remained so at 27 months follow up.

Conclusions and importance

Clearance of cell free DNA in metastatic uveal melanoma may be associated with radiographic response to immune checkpoint inhibitors.

[Side effects of dermato-oncologic therapies]

BACKGROUND

Immune checkpoint inhibitors (ICIs) such as PD(L)1 and CTLA4 antibodies as well as targeted therapies such as BRAF and MEK inhibitors have significantly improved the systemic treatment of skin cancer in adjuvant and advanced therapy settings. All these drugs differ in their spectrum of side effects.

MATERIALS AND METHODS

The aim of this article is to provide an overview of the spectrum of side effects of dermato-oncological therapies and their management, taking into account the current literature.

RESULTS

The most important side effects of ICIs, the CCR4 inhibitor mogamulizumab, the ImmTAC tebentafusp, the BRAF and MEK inhibitors and the multityrosine kinase inhibitor imatinib are considered.

CONCLUSIONS

Side effects can manifest themselves in all organ systems. Chronic side effects and long-term harm are possible, especially with ICIs, and require close therapy monitoring and patient education. Knowledge of the side effects and the temporal, sometimes delayed course of their occurrence are essential for diagnosis and prompt initiation of therapy.

The Future of Checkpoint Inhibitors in Uveal Melanoma: A Narrative Review

INTRODUCTION

Immune checkpoint inhibitors have made tremendous progress over the last decade in the treatment of cutaneous melanoma, but their application in uveal melanoma treatment is less successful, owing in part to the immunological privilege of the eye and the liver, the most frequent site of metastasis. Nevertheless, the therapeutic outcomes reported currently are less pessimistic.

METHODS

In this review, we provide an overview of recent studies of immune checkpoint inhibitors in uveal melanoma and its metastasis and classify studies in this field into three groups: monotherapy of immune checkpoint inhibitors, dual-agent immune checkpoint inhibitors, and immune checkpoint inhibitors combined with other systemic or regional therapies.

RESULTS

Briefly, monotherapy with immune checkpoint inhibitors performed poorly. Dual-agent immune checkpoint inhibitors had slightly better outcomes than traditional treatments, especially in specific patient populations. As for the combination therapy, the combination with other systemic therapies did not show superiority over dual-agent immune checkpoint inhibitors, but combination with hepatic regional therapies was quite promising. Moreover, research on emerging checkpoints is currently limited to the stage of mechanistic studies.

CONCLUSION

We propose that immune checkpoint inhibitors remain alternative treatments for patients with uveal melanoma, but factors such as cost-effectiveness should also be taken into account. The combination therapy with immune checkpoint inhibitors deserves to be further explored.

Specific oncogene activation of the cell of origin in mucosal melanoma

Mucosal melanoma (MM) is a deadly cancer derived from mucosal melanocytes. To test the consequences of MM genetics, we developed a zebrafish model in which all melanocytes experienced CCND1 expression and loss of PTEN and TP53. Surprisingly, melanoma only developed from melanocytes lining internal organs, analogous to the location of patient MM. We found that zebrafish MMs had a unique chromatin landscape from cutaneous melanoma. Internal melanocytes could be labeled using a MM-specific transcriptional enhancer. Normal zebrafish internal melanocytes shared a gene expression signature with MMs. Patient and zebrafish MMs have increased migratory neural crest gene and decreased antigen presentation gene expression, consistent with the increased metastatic behavior and decreased immunotherapy sensitivity of MM. Our work suggests the cell state of the originating melanocyte influences the behavior of derived melanomas. Our animal model phenotypically and transcriptionally mimics patient tumors, allowing this model to be used for MM therapeutic discovery.

Uveal melanoma immunogenomics predict immunotherapy resistance and susceptibility

Immune checkpoint inhibition has shown success in treating metastatic cutaneous melanoma but has limited efficacy against metastatic uveal melanoma, a rare variant arising from the immune privileged eye. To better understand this resistance, we comprehensively profile 100 human uveal melanoma metastases using clinicogenomics, transcriptomics, and tumor infiltrating lymphocyte potency assessment. We find that over half of these metastases harbor tumor infiltrating lymphocytes with potent autologous tumor specificity, despite low mutational burden and resistance to prior immunotherapies. However, we observe strikingly low intratumoral T cell receptor clonality within the tumor microenvironment even after prior immunotherapies. To harness these quiescent tumor infiltrating lymphocytes, we develop a transcriptomic biomarker to enable in vivo identification and ex vivo liberation to counter their growth suppression. Finally, we demonstrate that adoptive transfer of these transcriptomically selected tumor infiltrating lymphocytes can promote tumor immunity in patients with metastatic uveal melanoma when other immunotherapies are incapable.

Patterns of radiological response to tebentafusp in patients with metastatic uveal melanoma

Metastatic uveal melanoma (mUM) is a rare type of melanoma with poor outcomes. The first systemic treatment to significantly prolong overall survival (OS) in patients with mUM was tebentafusp, a bispecific protein that can redirect T-cells to gp-100 positive cells. However, the objective response rate according to Response Evaluation Criteria in Solid Tumors (RECIST) may underestimate the clinical impact of tebentafusp. As metabolic response assessed by PET Response Criteria in Solid Tumors (PERCIST) has been reported to better correlate with clinical outcome, we here compared the patterns of radiological and morphological responses in HLA-A*02:01-positive patients with mUM treated with tebentafusp. In the 19 enrolled patients, RECIST showed an overall response rate (ORR) of 10%, median progression-free survival of 2.8 months (95% CI 2.5-8.4), and median OS (mOS) of 18.8 months. In 10 patients, where both RECIST and PERCIST evaluation was available, the ORR was 10% for both; however, the PFS was longer for PERCIST compared to RECIST, 3.1 and 2.4 months, respectively. A poor agreement between the criteria was observed at all assessments (Cohen's kappa ≤0), yet they differed significantly only at the first on-treatment imaging ( P  = 0.037). Elevated baseline LDH and age were associated with an increased risk for RECIST progression, while lymphocyte decrease after the first infusions correlated to reduced risk of RECIST progression. Detectable ctDNA at baseline did not correlate with progression. Early response to tebentafusp may be incompletely captured by conventional imaging, leading to a need to consider both tumor morphology and metabolism.

US physician perspective on the use of biomarker and ctDNA testing in patients with melanoma

New treatments have increased survival of patients with melanoma, and methods to monitor patients throughout the disease process are needed. Circulating tumor DNA (ctDNA) is a predictive and prognostic biomarker that may allow routine, real-time monitoring of disease status. We surveyed 44 US physicians to understand their preferences and practice patterns for biomarker and ctDNA testing in their patients with melanoma. Tumor biomarker testing was often ordered in stage IIIA-IV patients. Barriers to biomarker testing include insufficient tissue (60%) and lack of insurance coverage (54%). ctDNA testing was ordered by 16-18% of physicians for stages II-IV. Reasons for not using ctDNA testing included lack of prospective data (41%), ctDNA testing used for research only (18%), and others. Physicians (≥74%) believed that ctDNA assays could help with monitoring and treatment selection throughout the disease process. Physicians consider ctDNA testing potentially valuable for clinical decision-making but cited concerns that should be addressed.

Cutaneous adverse effects induced by tebentafusp in patients with metastatic uveal melanoma: a case series and treatment insights

Tebentafusp, recently approved by the FDA as an immunotherapy agent, has shown great promise in improving outcomes for metastatic uveal melanoma. In this case series, we present six patients treated with tebentafusp at our institution, focusing on the associated cutaneous adverse reactions and their management. A better understanding of the cutaneous adverse reactions associated with tebentafusp is important because, given its promising treatment outcomes, the use of tebentafusp will likely become more widespread. This study highlights the range of possible outcomes and effective treatment regimens for mild-to-severe cutaneous reactions, ensuring that patients can continue tebentafusp treatment without interruption in most cases.

HLA-class II restricted TCR targeting human papillomavirus type 18 E7 induces solid tumor remission in mice

T cell receptor (TCR)-engineered T cell therapy is a promising potential treatment for solid tumors, with preliminary efficacy demonstrated in clinical trials. However, obtaining clinically effective TCR molecules remains a major challenge. We have developed a strategy for cloning tumor-specific TCRs from long-term surviving patients who have responded to immunotherapy. Here, we report the identification of a TCR (10F04), which is human leukocyte antigen (HLA)-DRA/DRB1*09:01 restricted and human papillomavirus type 18 (HPV18) E784-98 specific, from a multiple antigens stimulating cellular therapy (MASCT) benefited metastatic cervical cancer patient. Upon transduction into human T cells, the 10F04 TCR demonstrated robust antitumor activity in both in vitro and in vivo models. Notably, the TCR effectively redirected both CD4+ and CD8+ T cells to specifically recognize tumor cells and induced multiple cytokine secretion along with durable antitumor activity and outstanding safety profiles. As a result, this TCR is currently being investigated in a phase I clinical trial for treating HPV18-positive cancers. This study provides an approach for developing safe and effective TCR-T therapies, while underscoring the potential of HLA class II-restricted TCR-T therapy as a cancer treatment.

Targeted therapy in ophthalmic oncology: The current status

There have been rapid advancements in the field of ocular oncology for the diagnosis and management of intraocular, adnexal, and orbital tumors. Targeted therapy is in the forefront of medical research in all fields including ocular oncology. Targeted therapy include drugs that target specific genetic mutations, pathways or proteins involved in the development of cancer. In contrast to traditionally used chemotherapy, drugs used in targeted therapy are highly specific for tumor cells and preserve the function of normal cells. This review aims to familiarize ophthalmologists with the drugs that are currently approved or undergoing clinical trials for use in ocular oncology. Targeted therapy is particularly useful for locally advanced or metastatic tumors, including but not limited to eyelid and periocular basal cell carcinoma, periocular cutaneous and conjunctival squamous cell carcinoma, ocular adnexal lymphoma, conjunctival melanoma, and uveal melanoma. The results are promising with improved survival outcomes and better tolerability than chemotherapeutic drugs.

Uveal melanoma: Current evidence on prognosis, treatment and potential developments

Uveal Melanoma (UM) is a rare disease, yet it is the most common primary intraocular malignancy in adult patients. Despite continuous advancements and research, the risk of metastasis remains high. It is possible to stratify patients according to their risk of metastases using a variety of known risk factors. Even though there is no gold standard for the prognostication of patients with uveal melanoma, it is becoming increasingly clear that combining histo-pathological, patient-related and molecular prognostic markers allows a more accurate prediction of the metastatic risk than by using one parameter. Primary UM in the eye are treated very effectively with eye-sparing radiation-based techniques or enucleation. However, it is not yet possible to prevent or treat metastases with the current therapeutic options. Nonetheless, the efforts to find new therapeutic targets continue and progress is being made, especially in the field of targeted therapy, as exemplified by the anti-gp100 bispecific molecule Tebentafusp. This review delves into the history of uveal melanoma, its incidence, presentation and diagnosis, the known prognostic factors and the treatment options, both for the primary tumour and for metastases. We show that different populations may have different risks for developing UM, and that each country should evaluate their own patients.

Updates in the Management of Uveal Melanoma

ABSTRACT

Uveal melanoma (UM), arising from intraocular melanocytes, poses a complex clinical challenge with a substantial risk of distant metastasis, often to the liver. Molecular profiling, encompassing genetic, cytogenetic, gene expression, and immunological subsets, plays a pivotal role in determining prognoses. The evolving landscape includes promising systemic treatments, such as tebentafusp, a novel immune-modulating bispecific fusion protein, and targeted therapies. Combined regional and systemic approaches, including immune checkpoint inhibitors and innovative liver-directed therapy, are also under investigation. Although recent progress has improved outcomes, ongoing research aims to address the unique challenges of UM and develop effective therapies, particularly for HLA-A*02:01-negative patients who represent a significant unmet medical need. This review comprehensively discusses the molecular characteristics of UM, risk stratification methods, and the current and future spectrum of regional and systemic therapeutic modalities.

CAR-T cell therapy targeting surface expression of TYRP1 to treat cutaneous and rare melanoma subtypes

A major limitation to developing chimeric antigen receptor (CAR)-T cell therapies for solid tumors is identifying surface proteins highly expressed in tumors but not in normal tissues. Here, we identify Tyrosinase Related Protein 1 (TYRP1) as a CAR-T cell therapy target to treat patients with cutaneous and rare melanoma subtypes unresponsive to immune checkpoint blockade. TYRP1 is primarily located intracellularly in the melanosomes, with a small fraction being trafficked to the cell surface via vesicular transport. We develop a highly sensitive CAR-T cell therapy that detects surface TYRP1 in tumor cells with high TYRP1 overexpression and presents antitumor activity in vitro and in vivo in murine and patient-derived cutaneous, acral and uveal melanoma models. Furthermore, no systemic or off-tumor severe toxicities are observed in an immunocompetent murine model. The efficacy and safety profile of the TYRP1 CAR-T cell therapy supports the ongoing preparation of a phase I clinical trial.

Anti-PD-1/PD-L1 therapy for colorectal cancer: Clinical implications and future considerations

Colorectal cancer (CRC) is the third most prevalent cancer in the world. The PD-1/PD-L1 pathway plays a crucial role in modulating immune response to cancer, and PD-L1 expression has been observed in tumor and immune cells within the tumor microenvironment of CRC. Thus, immunotherapy drugs, specifically checkpoint inhibitors, have been developed to target the PD-1/PD-L1 signaling pathway, thereby inhibiting the interaction between PD-1 and PD-L1 and restoring T-cell function in cancer cells. However, the emergence of resistance mechanisms can reduce the efficacy of these treatments. To counter this, monoclonal antibodies (mAbs) have been used to improve the efficacy of CRC treatments. mAbs such as nivolumab and pembrolizumab are currently approved for CRC treatment. These antibodies impede immune checkpoint receptors, including PD-1/PD-L1, and their combination therapy shows promise in the treatment of advanced CRC. This review presents a concise overview of the use of the PD-1/PD-L1 blockade as a therapeutic strategy for CRC using monoclonal antibodies and combination therapies. Additionally, this article outlines the function of PD-1/PD-L1 as an immune response suppressor in the CRC microenvironment as well as the potential advantages of administering inflammatory agents for CRC treatment. Finally, this review analyzes the outcomes of clinical trials to examine the challenges of anti-PD-1/PD-L1 therapeutic resistance.

Evaluation of Circulating Tumor DNA as a Liquid Biomarker in Uveal Melanoma

Purpose

Uveal melanoma (UM) has a high propensity to metastasize. Prognosis is associated with specific driver mutations and copy number variations (CNVs), but limited primary tumor tissue is available for molecular characterization due to eye-sparing irradiation treatment. This study aimed to assess the rise in circulating tumor DNA (ctDNA) levels in UM and evaluate its efficacy for CNV-profiling of patients with UM.

Methods

In a pilot study, we assessed ctDNA levels in the blood of patients with UM (n = 18) at various time points, including the time of diagnosis (n = 13), during fractionated stereotactic radiotherapy (fSRT) treatment (n = 6), and upon detection of metastatic disease (n = 13). Shallow whole-genome sequencing (sWGS) combined with in silico size-selection was used to identify prognostically relevant CNVs in patients with UM (n = 26) from peripheral blood retrieved at the time of diagnosis (n = 9), during fSRT (n = 5), during post-treatment follow-up (n = 4), metastasis detection (n = 6), and metastasis follow-up (n = 4).

Results

A total of 34 patients had blood analyzed for ctDNA detection (n = 18) and/or CNV analysis (n = 26) at various time points. At the time of diagnosis, 5 of 13 patients (38%) had detectable ctDNA (median = 0 copies/mL). Upon detection of metastatic disease, ctDNA was detected in 10 of 13 patients (77%) and showed increased ctDNA levels (median = 24 copies/mL, P < 0.01). Among the six patients analyzed during fSRT, three (50%) patients had detectable ctDNA at baseline and three of six (50%) patients had undetectable levels of ctDNA. During the fSRT regimen, ctDNA levels remained unchanged (P > 0.05). The ctDNA fractions were undetectable to low in localized disease, and sWGS did not elucidate chromosome 3 status from blood samples. However, in 7 of 10 (70%) patients with metastases, the detection of chromosome 3 loss corresponded to the high metastatic-risk class.

Conclusions

The rise in ctDNA levels observed in patients with UM harboring metastases suggests its potential utility for CNV profiling. These findings highlight the potential of using ctDNA for metastasis detection and patient inclusion in therapeutic studies targeting metastatic UM.

Uveal melanoma: Recent advances in immunotherapy

Uveal melanoma (UM) is the most common primary intraocular cancer in adults. The incidence in Europe and the United States is 6-7 per million population per year. Although most primary UMs can be successfully treated and locally controlled by irradiation therapy or local tumor resection, up to 50% of UM patients develop metastases that usually involve the liver and are fatal within 1 year. To date, chemotherapy and targeted treatments only obtain minimal responses in patients with metastatic UM, which is still characterized by poor prognosis. No standard therapeutic approaches for its prevention or treatment have been established. The application of immunotherapy agents, such as immune checkpoint inhibitors that are effective in cutaneous melanoma, has shown limited effects in the treatment of ocular disease. This is due to UM's distinct genetics, natural history, and complex interaction with the immune system. Unlike cutaneous melanomas characterized mainly by BRAF or NRAS mutations, UMs are usually triggered by a mutation in GNAQ or GNA11. As a result, more effective immunotherapeutic approaches, such as cancer vaccines, adoptive cell transfer, and other new molecules are currently being studied. In this review, we examine novel immunotherapeutic strategies in clinical and preclinical studies and highlight the latest insight in immunotherapy and the development of tailored treatment of UM.

Imipridones inhibit tumor growth and improve survival in an orthotopic liver metastasis mouse model of human uveal melanoma

Purpose

Uveal melanoma (UM) is a highly aggressive disease with very few treatment options. We previously demonstrated that mUM is characterized by high oxidative phosphorylation (OXPHOS). Here we tested the anti-tumor, signaling and metabolic effects of imipridones, CLPP activators which reduce OXPHOS indirectly and have demonstrated safety in patients.

Experimental Design

We assessed CLPP expression in UM patient samples. We tested the effects of imipridones (ONC201, ONC212) on the growth, survival, signaling and metabolism of UM cell lines in vitro, and for therapeutic effects in vivo in UM liver metastasis models.

Results

CLPP expression was confirmed in primary and mUM patient samples. ONC201/212 treatment of UM cell lines in vitro decreased OXPHOS effectors, inhibited cell growth and migration, and induced apoptosis. ONC212 increased metabolic stress and apoptotic pathways, inhibited amino acid metabolism, and induced cell death-related lipids. ONC212 also decreased tumor burden and increased survival in vivo in two UM liver metastasis models.

Conclusion

Imipridones are a promising strategy for further testing and development in mUM.

Tumor Pigmentation Does Not Affect Light-Activated Belzupacap Sarotalocan Treatment but Influences Macrophage Polarization in a Murine Melanoma Model

Purpose

Pigmentation in uveal melanoma is associated with increased malignancy and is known as a barrier for photodynamic therapy. We investigated the role of pigmentation in tumor behavior and the response to light-activated Belzupacap sarotalocan (Bel-sar) treatment in a pigmented (wild type) and nonpigmented (tyrosinase knock-out [TYR knock-out]) cell line in vitro and in a murine model.

Methods

The B16F10 (TYR knock-out) was developed using CRISPR/Cas9. After the treatment with light-activated Bel-sar, cytotoxicity and exposure of damage-associated molecular patterns (DAMPs) were measured by flow cytometry. Treated tumor cells were co-cultured with bone marrow-derived macrophages (BMDMs) and dendritic cells (DCs) to assess phagocytosis and activation. Both cell lines were injected subcutaneously in syngeneic C57BL/6 mice.

Results

Knock-out of the tyrosinase gene in B16F10 led to loss of pigmentation and immature melanosomes. Pigmented tumors contained more M1 and fewer M2 macrophages compared with amelanotic tumors. Bel-sar treatment induced near complete cell death, accompanied with enhanced exposure of DAMPs in both cell lines, resulting in enhanced phagocytosis of BMDMs and maturation of DCs. Bel-sar treatment induced a shift to M1 macrophages and delayed tumor growth in both in vivo tumor models. Following treatment, especially the pigmented tumors and their draining lymph nodes contained IFN-gamma positive CD8+T cells.

Conclusions

Pigmentation influenced the type of infiltrating macrophages in the tumor, with more M1 macrophages in pigmented tumors. Belzupacap sarotalocan treatment induced immunogenic cell death and tumor growth delay in pigmented as well as in nonpigmented models and stimulated M1 macrophage influx in both models.

Tebentafusp as a Promising Drug for the Treatment of Uveal Melanoma

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults and commonly occurs in the Caucasian population. The malignancy involves the uvea of the eye, which includes the iris, ciliary body, and choroid. The etiology of UM is still not well understood, but age is a risk factor. Symptoms include blurred vision, redness of the eye, floaters, dark spots, a change in the size of the pupil, and loss of vision. The location, shape, and size of the tumor are important for therapeutic purposes. Treating metastasis is always a challenge in UM cases. In cases of lung metastasis, the survival rate decreases. Treatment includes surgery, laser therapy, immunotherapy, hormone therapy, and chemotherapy. Recently, in 2022, the United States Food and Drug Administration (FDA) approved the drug tebentafusp. Tebentafusp was developed to target the most common HLA complex in humans. The present review discusses the indications for the use of a new drug tebentafusp, its mechanism of action, dose, pharmacokinetics, results of clinical trials conducted, and adverse effects like cytokine release syndrome. Hence, tebentafusp is the first T cell receptor (TCR) therapeutic drug that could be considered for the treatment of UM.

Promising and Minimally Invasive Biomarkers: Targeting Melanoma

The therapeutic landscape of malignant melanoma has been radically reformed in recent years, with novel treatments emerging in both the field of cancer immunotherapy and signalling pathway inhibition. Large-scale tumour genomic characterization has accurately classified malignant melanoma into four different genomic subtypes so far. Despite this, only somatic mutations in BRAF oncogene, as assessed in tumour biopsies, has so far become a validated predictive biomarker of treatment with small molecule inhibitors. The biology of tumour evolution and heterogeneity has uncovered the current limitations associated with decoding genomic drivers based only on a single-site tumour biopsy. There is an urgent need to develop minimally invasive biomarkers that accurately reflect the real-time evolution of melanoma and that allow for streamlined collection, analysis, and interpretation. These will enable us to face challenges with tumour tissue attainment and process and will fulfil the vision of utilizing "liquid biopsy" to guide clinical decisions, in a manner akin to how it is used in the management of haematological malignancies. In this review, we will summarize the most recent published evidence on the role of minimally invasive biomarkers in melanoma, commenting on their future potential to lead to practice-changing discoveries.

Three-Year Overall Survival with Tebentafusp in Metastatic Uveal Melanoma

BACKGROUND

Tebentafusp, a T-cell receptor-bispecific molecule that targets glycoprotein 100 and CD3, is approved for adult patients who are positive for HLA-A*02:01 and have unresectable or metastatic uveal melanoma. The primary analysis in the present phase 3 trial supported a long-term survival benefit associated with the drug.

METHODS

We report the 3-year efficacy and safety results from our open-label, phase 3 trial in which HLA-A*02:01-positive patients with previously untreated metastatic uveal melanoma were randomly assigned in a 2:1 ratio to receive tebentafusp (tebentafusp group) or the investigator's choice of therapy with pembrolizumab, ipilimumab, or dacarbazine (control group), with randomization stratified according to the lactate dehydrogenase level. The primary end point was overall survival.

RESULTS

At a minimum follow-up of 36 months, median overall survival was 21.6 months in the tebentafusp group and 16.9 months in the control group (hazard ratio for death, 0.68; 95% confidence interval, 0.54 to 0.87). The estimated percentage of patients surviving at 3 years was 27% in the tebentafusp group and 18% in the control group. The most common treatment-related adverse events of any grade in the tebentafusp group were rash (83%), pyrexia (76%), pruritus (70%), and hypotension (38%). Most tebentafusp-related adverse events occurred early during treatment, and no new adverse events were observed with long-term administration. The percentage of patients who discontinued treatment because of adverse events continued to be low in both treatment groups (2% in the tebentafusp group and 5% in the control group). No treatment-related deaths occurred.

CONCLUSIONS

This 3-year analysis supported a continued long-term benefit of tebentafusp for overall survival among adult HLA-A*02:01-positive patients with previously untreated metastatic uveal melanoma. (Funded by Immunocore; IMCgp100-202 ClinicalTrials.gov number, NCT03070392; EudraCT number, 2015-003153-18.).

T cell receptor therapeutics: immunological targeting of the intracellular cancer proteome

The T cell receptor (TCR) complex is a naturally occurring antigen sensor that detects, amplifies and coordinates cellular immune responses to epitopes derived from cell surface and intracellular proteins. Thus, TCRs enable the targeting of proteins selectively expressed by cancer cells, including neoantigens, cancer germline antigens and viral oncoproteins. As such, TCRs have provided the basis for an emerging class of oncology therapeutics. Herein, we review the current cancer treatment landscape using TCRs and TCR-like molecules. This includes adoptive cell transfer of T cells expressing endogenous or engineered TCRs, TCR bispecific engagers and antibodies specific for human leukocyte antigen (HLA)-bound peptides (TCR mimics). We discuss the unique complexities associated with the clinical development of these therapeutics, such as HLA restriction, TCR retrieval, potency assessment and the potential for cross-reactivity. In addition, we highlight emerging clinical data that establish the antitumour potential of TCR-based therapies, including tumour-infiltrating lymphocytes, for the treatment of diverse human malignancies. Finally, we explore the future of TCR therapeutics, including emerging genome editing methods to safely enhance potency and strategies to streamline patient identification.

PRAME Expression: A Target for Cancer Immunotherapy and a Prognostic Factor in Uveal Melanoma

Purpose

Uveal melanoma (UM) is a rare disease with a high mortality, and new therapeutic options are being investigated. Preferentially Expressed Antigen in Melanoma (PRAME) is a cancer testis antigen, expressed in the testis, but also in cancers, including uveal melanoma. PRAME is considered a target for immune therapy in several cancers, and PRAME-specific T cell clones have been shown to kill UM cells.

Methods

We studied the literature on PRAME expression in hematological and solid malignancies, including UM, and its role as a target for immunotherapy. The distribution of tumor features was compared between PRAME-high and PRAME-low UM in a 64-patient cohort from the Leiden University Medical Center (LUMC) and in the Cancer Genome Atlas (TCGA) cohort of 80 cases and differential gene expression analysis was performed in the LUMC cohort.

Results

PRAME is expressed in many malignancies, it is frequently associated with a negative prognosis, and can be the target of T cell receptor (TCR)-transduced T cells, a promising treatment option with high avidity and safety. In UM, PRAME is expressed in 26% to 45% of cases and is correlated with a worse prognosis. In the LUMC and the TCGA cohorts, high PRAME expression was associated with larger diameter, higher Tumor-Node-Metastasis (TNM) stage, more frequent gain of chromosome 8q, and an inflammatory phenotype.

Conclusions

We confirm that PRAME is associated with poor prognosis in UM and has a strong connection with extra copies of 8q. We show that PRAME-specific immunotherapy in an adjuvant setting is promising in treatment of malignancies, including UM.