Metastatic Uveal Melanoma Patients Research Articles

Detection of the Uveal Melanoma-Associated Mutation GNAQ Q209P from Liquid Biopsy Using CRISPR/Cas12a Technology.

Uveal melanoma (UM) is a rare ocular tumor characterized by high metastasis risk and poor prognosis. The in-depth characterization of UM's molecular profile is critical for better disease classification and prognosis. Furthermore, the development of detection tools to monitor UM evolution upon treatment is of great interest for designing optimal therapeutic strategies. However, commonly used techniques, such as ddPCR or NGS, are costly, and they involve sophisticated equipment and complex experimental design. The development of alternative sensing methods that are fast, simple, and inexpensive would be of great benefit to improve UM's diagnosis and management, especially when combined with liquid biopsy. Samples from liquid biopsy can be obtained with minimal invasiveness, and the detection of circulating tumor DNA (ctDNA) in UM patients' plasma has proven useful for the diagnosis of metastasis, prognosis prediction, and disease monitoring. In this context, CRISPR/Cas12a-derived molecular sensors, thanks to their high specificity and sensitivity and their potential for point of care diagnosis, are particularly interesting. Here, we developed a CRISPR/Cas12a-based approach for the specific detection of the UM-related mutation GNAQ Q209P that relies on the design of highly specific crRNAs. Coupled with allele-specific PCR, it constitutes a sensitive platform for liquid biopsy detection, capable of sensing GNAQ Q209P in plasma samples with a low ctDNA concentration and fractional abundance. Finally, our method was validated using plasma samples from metastatic UM patients.

1133P SF3B1 mutation predicts improved overall survival in metastatic uveal melanoma patients: Molecular and clinical correlates

1133P SF3B1 mutation predicts improved overall survival in metastatic uveal melanoma patients: Molecular and clinical correlates

Determinants of overall survival in patients with metastatic uveal melanoma.

Despite improvements in the treatment of primary uveal melanoma (UM), patients with metastatic disease continue to exhibit poor survival. A retrospective review of metastatic UM patients at Yale (initial cohort) and Memorial Sloan Kettering (validation cohort) was conducted. Cox proportional hazards regression was used to determine baseline factors that are associated with overall survival, including sex, Eastern Cooperative Oncology Group (ECOG) Performance Status Scale, laboratory measurements, metastasis location, and use of anti-CTLA-4 and anti-PD-1 therapies. Differences in overall survival were analyzed using Kaplan-Meier analysis. A total of 89 patients with metastatic UM were identified; 71 and 18, in the initial and validation cohorts, respectively. In the initial cohort, median follow-up was 19.8months (range, 2-127months) and median overall survival was 21.8months (95% CI, 16.6-31.3). Female sex, anti-CTLA-4, and anti-PD-1 therapy were associated with better survival outcomes with adjusted death hazard ratios (HRs) of 0.40 (95% CI, 0.20-0.78), 0.44 (0.20-0.97), and 0.42 (0.22-0.84), respectively, whereas development of hepatic metastases and ECOG score ≥1 (per 1 U/L) were associated with worse survival outcomes with HRs of 2.86 (1.28-7.13) and 2.84 (1.29-6.09), respectively. In both the initial and validation cohorts, use of immune checkpoint inhibitors was associated with improved overall survival after adjusting for sex and ECOG score, with death HRs of 0.22 (0.08-0.56) and 0.04 (0.002-0.26), respectively. Development of extrahepatic-only metastases, ECOG of 0, immune checkpoint therapy, and female sex were each associated with more than 2-fold reductions in risk of death. Metastatic uveal melanoma patients face limited treatment options and poor survival rates. Results from this retrospective analysis indicate that immune checkpoint inhibitors, such as anti-CTLA-4 and anti-PD-1 therapies, were associated with improved survival outcomes. Factors such as extrahepatic-only metastases, better baseline performance status, and female sex contributed to a more than 2-fold reduction in death risk. These findings highlight the potential of immunotherapy in treating metastatic uveal melanoma.

Differences in glucose metabolic activity in liver metastasis separates two groups of metastatic uveal melanoma patients with different prognosis.

Uveal melanoma metastasizes to the liver. We aimed to explore the metabolic activity of liver metastases (LM) as a biomarker for survival. We analyzed newly diagnosed patients with metastatic UM (MUM) with LM detected by liver-directed imaging and had undergone a PET/CT at diagnosis. 51 patients were identified between 2004 and 2019. Median age was 62 years, 41% male and 22% ECOG ≥1. LDH, ALP, and GGT were elevated in 49%, 37%, and 57% of patients. Median LM SUVmax was 8.5 (3-42.2). Same size lesions presented a wide range of metabolic activity. Median OS was 17.3 m (95% CI:10.6-23.9). Patients with SUVmax ≥8.5 had an OS of 9.4 m (95% CI:6.4-12.3), whereas patients with SUVmax <8.5 had an OS of 38.4 m (95% CI:21.4-55.5; p < 0.0001, HR = 2.9). We observed similar results when studying M1a disease separately. Multivariate analysis showed SUVmax as an independent prognostic factor for the whole population and those with M1a disease. Increased metabolic activity of LM seems to be an independent predictor of survival. MUM is a heterogeneous disease and metabolic activity probably reflects a different intrinsic behavior.

Abstract LB118: Evidence of tumor response in orbital lesions treated with tebentafusp in metastatic uveal melanoma patients

Abstract Background: Tebentafusp, a bispecific (gp100 x CD3) ImmTAC that can redirect T cells to target gp100+ melanoma cells, has shown a superior overall survival (OS) benefit compared to investigator choice for HLA-A*02:01+ patients (pts) with untreated metastatic uveal melanoma (mUM). Although local control rates for primary UM are high, a minority of patients with mUM have recurrent or untreated orbital disease. Here we present safety and efficacy from tebentafusp treated mUM pts with orbital lesions including intraocular lesions. Methods: Tumor response according to RECIST v1.1 and ocular Adverse Events (AEs) were assessed in a pooled analysis of mUM pts with orbital lesions from 3 tebentafusp trials: IMCgp100-01 (Phase (Ph) 1/2, 19 2L+ mUM pts), IMCgp100-102 (Ph 1/2 2L+ mUM, 146 pts) and IMCgp100-202 (Ph3 1L mUM, 245 tebentafusp pts). Pre-treatment biopsies, taken prior to the IMCgp100-202 trial, were analyzed by immunohistochemistry for gp100 and CD3+ or CD8+ T cell infiltration prior to tebentafusp treatment. Results: In the 3 clinical trials, 12 mUM pts with radiologically detectable orbital lesions received tebentafusp, the majority of which were intra-ocular. All lesions were stable or had achieved shrinkage. 5/12 pts had orbital target lesions (TL), of which 4/5 had achieved tumor shrinkage (best % change -3 to -40) and 1/5 had no change in tumor size. All non-target orbital lesions were stable or achieved a complete response. 9 eye disorder AEs occurred in 5 pts, the majority of which were G1. The most common (7/9) AEs were extra-ocular local edema. One G3 eye pain AE, in a post eviscerated eye, did not resolve and occurred in the setting of disease progression resulting in treatment discontinuation. All other eye disorder AEs recovered and none led to tebentafusp discontinuation. 37 primary UM and 195 liver metastasis baseline biopsies were evaluated. Expression of gp100 in primary UM and mUM was high (95% and 80%, respectively). CD3+ and CD8+ T cell numbers were generally lower in primary UM compared to liver metastasis (median CD3: 231 and 504 cells/mm2, p=0.035; CD8: 121 and 238 cells/mm2, p=0.53, respectively). Conclusions: Following tebentafusp treatment, tumor reduction or stabilization of all orbital lesions including intra-ocular lesions were observed. Most AEs were extra-ocular mild local edema. Primary UM showed a high level of gp100 expression and also T cell infiltration. These preliminary signals of tebentafusp activity in orbital disease, including intra-ocular lesions, suggest a role for tebentafusp as a neoadjuvant therapy in UM and warrant further investigation. Citation Format: Marcus O. Butler, Takami Sato, Friedegund Meier, Ramakrishna Edukulla, Sarah Stanhope, Fraser S. Peck, Jessica C. Hassel. Evidence of tumor response in orbital lesions treated with tebentafusp in metastatic uveal melanoma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB118.

Abstract CT207: Phase I trial of vesicular stomatitis virus expressing human interferon beta and tyrosinase related protein 1 (VSV-IFNb-TYRP1) in metastatic ocular melanoma

Abstract Oncologic viruses (OV) can induce tumor death through both direct oncolysis and immune-mediated destruction. Our study investigates the use of a novel OV with a Vesicular Stomatitis Virus (VSV) vector modified to express interferon-beta (IFN-b) and Tyrosinase Related Protein 1 (TYRP1) (VSV-IFNb-TYRP1). VSV is an attractive vector since humans are not naturally infected with VSV; thus, pre-existing immunity is minimal. IFN-b leads to increased T-cell responses and tumor cell apoptosis, while TYRP1, a melanocyte differentiation antigen, increases immunogenicity of the therapy. We conducted a Phase 1 clinical trial with a 3+3 design in patients with metastatic uveal melanoma. VSV-IFNb-TYRP1 was injected into a liver metastasis under image guidance, then administered on the same day as a single intravenous (IV) infusion. IV doses started at dose level (DL) 1 1 × 1010 TCID50, then escalated to DL2 3 × 10 10, DL3 1 × 1011, and DL4 3 × 1011. The dose delivered intratumorally (IT) varied based on the IV dose. The primary endpoints were safety and maximum tolerated dose (MTD). Efficacy was a secondary endpoint. Correlative studies focused on understanding viral pharmacokinetics (PK) and immunological responses induced by VSV-IFNb-TYRP1 therapy. Twelve patients with previously treated metastatic uveal melanoma were enrolled. Median follow up was 19.1 months. Four DLs were evaluated with one patient at DL4 experiencing dose limiting toxicities (DLTs), including decreased platelet count (grade 3), increased aspartate aminotransferase (AST), and cytokine release syndrome (CRS). Non-DLTs at DL4 were fatigue, fever, CRS, hematological toxicities (decreased platelets and lymphocytes), and AST elevation. Four patients had stable disease (SD) and 8 had progressive disease (PD) as their best response. ELIspot data show that three of the four patients with response to TYRP1 also had a response to gp100, suggesting possible epitope spreading. These four patients received immune checkpoint inhibitor treatment as the next line of therapy, which led to clinical benefit for two patients. Our study evaluated VSV-IFNb-TYRP1 administered via IT and IV routes in a previously treated population of metastatic uveal melanoma patients and found no major safety events. Although there were no clear objective responses to VSV-IFNb-TYRP1, dose-dependent immunogenicity to melanoma antigens was seen. While OV response alone is not sufficient for clinical benefit, the evidence of epitope spreading is encouraging. Future studies of VSV-IFNb-TYRP1 will evaluate combinations with other therapies. Citation Format: Katherine E. Smith, Adam Weisbrod, Carrie Strand, Jacob Allerd, Jose S. Pulido, Alysha Newsom, Lianwen Zhang, Nandakumar Packiriswamy, Heather Montane, Lisa Kottschade, Anastasios Dimou, Yiyi Yan, Markovic Svetomir, Kah Whye Peng, Richard G. Vile, Matthew S. Block, Roxana S. Dronca. Phase I trial of vesicular stomatitis virus expressing human interferon beta and tyrosinase related protein 1 (VSV-IFNb-TYRP1) in metastatic ocular melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT207.

Hepatic Radiotherapy in Addition to Anti-PD-1 for the Treatment of Metastatic Uveal Melanoma Patients.

Uveal melanoma is the most common ocular tumor with frequent metastatic spread to the liver. Immune checkpoint inhibitors have demonstrated poor results in this disease. The addition of hepatic radiotherapy to anti-PD-1 could enhance the sensitivity to immunotherapy. In this study, patients treated with pembrolizumab and who have undergone hepatic radiotherapy have been retrospectively evaluated. Twenty-two patients have been considered. Six patients (27.3%) achieved a partial response and 3 (13.6%) a stable disease. Disease control rate was 40.9%. Thirteen patients (59.1%) had progression as best response. The median PFS was 4.8 months and 6 months PFS rate 45.4%. The median OS was 21.2 months, while 1 year OS rate was 72.7%. Longer survival was observed in patients who achieved a partial response on irradiated metastases (HR 0.23, 95% CI 0.06-0.83) or progressed after 6 months (HR 0.12-95% CI 0.03-0.44). No radiotherapy-related or grade 3-4 adverse events were reported. This study demonstrates that the addition of hepatic radiotherapy to anti-PD-1 treatment can be a valid option for the treatment of metastatic uveal melanoma, particularly for HLA A 02:01 negative patients. Prospective studies should be conducted to confirm these data.

Tebentafusp for the treatment of HLA-A*02:01–positive adult patients with unresectable or metastatic uveal melanoma

ABSTRACT Introduction Metastatic uveal melanoma is associated with poor prognosis and few treatment options. Tebentafusp recently became the first FDA-approved agent for metastatic uveal melanoma. Areas covered In this review, we describe the mechanism of action of tebentafusp as well as preclinical data showing high tumor specificity of the drug. We also review promising early-phase trials in which tebentafusp demonstrated activity in metastatic uveal melanoma patients with an acceptable toxicity profile that included cytokine-mediated, dermatologic-related, and liver-related adverse events. Finally, we summarize findings from a pivotal phase III randomized trial in which tebentafusp demonstrated significant improvement in overall survival in comparison with investigator choice therapy. Expert opinion Tebentafusp has transformed the treatment paradigm for metastatic uveal melanoma and should be the preferred frontline agent for most HLA-A*0201 positive patients. However, patients with rapidly progressing disease or high tumor benefit may not derive the same benefit. Areas of future study should focus on its role in the adjuvant setting as well as strategies to improve the efficacy of tebentafusp in the metastatic setting.

Tebentafusp-tebn: A Novel Bispecific T-Cell Engager for Metastatic Uveal Melanoma

Uveal melanoma is the most common intraocular cancer in adults. Metastatic uveal melanoma has a poor prognosis. Tebentafusp-tebn is the first drug in the new immune mobilizing monoclonal T-cell receptors against cancer (ImmTAC) class of T cell–directed therapy. Tebentafusp-tebn has been shown in a randomized phase III clinical trial to lead to improved overall survival and progression-free survival when compared with single-agent pembrolizumab, ipilimumab, or dacarbazine in previously untreated human leukocyte antigen (HLA)-A*02:01-positive metastatic uveal melanoma patients. Tebentafusp-tebn is now approved by the US Food and Drug Administration in HLA-A*02:01-positive uveal melanoma patients as first-line therapy in the metastatic setting.

MBD4 deficiency is predictive of response to immune checkpoint inhibitors in metastatic uveal melanoma patients

BackgroundMBD4 mutations have been reported in uveal melanomas, acute myeloid leukemias, colorectal adenocarcinomas, gliomas, and spiradenocarcinomas and cause a hypermutated phenotype. Although metastatic uveal melanomas (mUM) are usually resistant to immune checkpoint inhibitors (ICI), the first reported MBD4-mutated (MBD4m) patient responded to ICI, suggesting that MBD4 mutation may predict response to ICI. MethodsRetrospective cohort of mUM patients treated with ICI. MBD4 was sequenced in a subset of these patients. ResultsThree hundred mUM patients were included. Median follow-up was 17.3 months. Ten patients with an objective response and 20 cases with stable disease for >12 months were observed, corresponding to an objective response rate of 3.3% and a clinical benefit (i.e., responder patients and stable disease) rate of 10%. Of the 131 tumors sequenced for MBD4, five (3.8%) were mutated. MBD4 mutation was associated with a better objective response rate as three out of five MBD4m versus 4% of MBD4 wild-type patients responded (p < 0.001). Of these five responders, three presented progressive disease at 2.8, 13.9, and 22.3 months. Median PFS was 4.0 months in MBD4 wild-type and 22.3 months in MBD4m patients (HR = 0.22; p = 0.01). Median OS in MBD4def patients was unreached as compared to 16.6 months in MBD4pro (HR = 0.11; 95% CI: 0.02–0.86; log-rank p-test = 0.04; Fig. 2e). ConclusionsIn mUM patients, MBD4 mutation is highly predictive for the response, PFS, and overall survival benefit to ICI. MBD4 could be a tissue-agnostic biomarker and should be sequenced in mUM, and other tumor types where MBD4 mutations are reported.

MBD4 deficiency is predictive of response to immune checkpoint inhibitors in metastatic uveal melanoma patients: A retrospective study.

e21601 Background: MBD4 encodes a glycosylase implicated in repair of lesions induced by DNA deamination and its inactivation in tumors is associated with a hypermutated phenotype. Uveal melanoma (UM) is a rare but aggressive form of melanoma carrying an extremely low mutation burden. Although metastatic UM (mUM) are usually resistant to immune checkpoint inhibitors (ICI), the first reported MBD4-mutated (MBD4m) patient responded to ICI, suggesting that MBD4 mutation may predict response to ICI. Since then, other MBD4-inactivated UMs, acute myeloid leukemias, colorectal adenocarcinomas, gliomas and spiradenocarcinoma cases have been reported. Methods: Retrospective cohort of mUM patients treated with ICI. MBD4 was sequenced in a subset of these patients. Results: Three hundred mUM patients were analyzed. Median follow-up was 17.3 months. Ten objective responses and 20 stable disease for &gt; 12 months were observed, corresponding to an objective response rate of 3.3% and a clinical benefit (CB; i.e. responder patients and stable disease) rate of 10%. Median progression-free survivals (PFS) in patients without and with CB were 3.1 and 16.3 months, respectively (p &lt; 0.0001). Of the 134 tumors sequenced for MBD4, five (3.7%) were mutated. MBD4 inactivation was associated with higher mutation burden (179 to 643 variants versus a median of 16 in MBD4 wild-type), better objective response rate as 60% of MBD4m versus 4% of MBD4-wild type patients responded (Fisher’s exact p-test = 0.0009). Median PFS was 4.0 months in MBD4-wild type and 22.3 months in MBD4m patients (HR = 0.22; p = 0.01). Median overall survival was 16.6 months in MBD4-wild type and unreached in MBD4m patients (HR = 0.11; p = 0.004). Conclusions: In mUM patients, MBD4 mutation is highly predictive for response to ICI, PFS and overall survival benefit. MBD4 could be a tissue-agnostic biomarker and should be sequenced in mUM and other tumor types where MBD4 mutations are reported.

SLC25A38 as a novel biomarker for metastasis and clinical outcome in uveal melanoma

Risk of metastasis is increased by the presence of chromosome 3 monosomy in uveal melanoma (UM). This study aimed to identify more accurate biomarker for risk of metastasis in UM. A total of 80 patients with UM from TCGA were assigned to two groups based on the metastatic status, and bioinformatic analyses were performed to search for critical genes for risk of metastasis. SLC25A38, located on chromosome 3, was the dominant downregulated gene in metastatic UM patients. Low expression of SLC25A38 was an independent predictive and prognostic factor in UM. The predictive potential of SLC25A38 expression was superior to that of pervious reported biomarkers in both TCGA cohort and GSE22138 cohort. Subsequently, its role in promoting metastasis was explored in vitro and in vivo. Knock-out of SLC25A38 could enhance the migration ability of UM cells, and promote distant metastasis in mice models. Through the inhibition of CBP/HIF-mediated pathway followed by the suppression of pro-angiogenic factors, SLC25A38 was situated upstream of metastasis-related pathways, especially angiogenesis. Low expression of SLC25A38 promotes angiogenesis and metastasis, and identifies increased metastatic risk and worse survival in UM patients. This finding may further improve the accuracy of prognostic prediction for UM.

Circulating MicroRNAs as Quantitative Biomarkers for Diagnosis and Prognosis of Uveal Melanoma.

For uveal melanoma (UM) patients, it is significant to establish diagnosis and prognosis evaluation systems through imaging techniques. However, imaging examinations are short of quantitative biomarkers and it is difficult to finish early diagnosis of UM. In order to discover new molecular biomarkers for the diagnosis and prognostic evaluation of UM, six circulating miRNAs (mir-132-3p, mir-21-5p, mir-34a-5p, mir-126-3p, mir-199a-3p, mir-214-3p) were chosen as candidates for independent validation. Validation of these miRNAs was performed in a cohort of 20 patients, including 10 spindle-shaped melanoma and 10 epithelioid cell melanoma, and 10 healthy donors. Then 5 patients with metastatic UM were included to validate the performance of miRNAs in advanced UM. Serum levels of miRNAs were determined using quantitative real-time PCR. We confirmed significantly higher levels of three miRNAs in serum of UM patients in comparison to healthy controls, and miR-199a-3p had the best performance (p < 0.0001; AUC = 0.985). MiR-214-3p and miR-21-5p were significantly upregulated in serum of epithelioid cell melanoma patients compared to spindle-shaped melanoma patients and miR-132-3p and, conversely, were significantly downregulated in serum of epithelioid cell melanoma patients. MiR-21-5p shows their best performance (p < 0.0001; AUC = 0.980). Both miR-199a-3p and miR-21-5p showed great performance in advanced UM. Significantly higher levels of miR-21-5p (p < 0.001) were found in serum of metastatic UM patients compared to patients with localized spindle-shaped melanoma, and significantly higher levels of miR-199a-3p (p < 0.001) were detected in serum of metastatic UM patients compared to healthy controls. Our preliminary data indicate promising diagnostic utility of circulating miR-199a-3p and promising prognostic utility of circulating miR-21-5p in both early and advanced UM patients.

Circulating immune profile can predict survival of metastatic uveal melanoma patients: results of an exploratory study

ABSTRACT Metastatic uveal melanoma (UM) is a poor prognosis malignancy. Immunotherapy is commonly employed, despite the low activity, considering the lack of other effective systemic treatments. In this study, the prognostic and predictive role of soluble immune checkpoints and inflammatory cytokines/chemokines in 22 metastatic UM patients was evaluated. Baseline levels of these molecules were assessed, as well as their changes during anti-PD-1 therapy. The correlation between soluble immune checkpoints/cytokines/chemokines and survival was analyzed. A comparison between circulating immune profile of metastatic cutaneous melanoma (CM), for which immunotherapy is a mainstay of treatment, and UM during anti-PD-1 therapy was also performed. Three immune molecules resulted significantly higher in metastatic UM patients with survival <6 months versus patients with survival ≥6 months: IL-8, HVEM and IDO activity. Considering these three molecules, we obtained a baseline score able to predict patients’ survival. The same three molecules, together with soluble(s) CD137, sGITR and sCD27, resulted significantly lower in patients with survival >30 months. We also observed an increase of sCD137, sCD28, sPD-1, sPD-L2 sLAG3, sCD80 and sTim3 during anti-PD-1 treatment, as well as IDO activity, IP-10 and CCL2. Several of these molecules were significantly higher in UM compared to CM patients during anti-PD-1 therapy. The analysis of circulating immune molecules allows to identify patients with poor prognosis despite immunotherapy and patients with long survival treated with an anti-PD-1 agent. The different serum concentration of these molecules during anti-PD-1 therapy between UM and CM reflects the different efficacy of immune checkpoint inhibitors.

Radiotherapy may augment response to immunotherapy in metastatic uveal melanoma patients

Uveal melanoma (UM) is a subtype of melanoma arising from the ocular region. Despite various local therapies available, a significant portion of patients develop distant metastases, primarily to the liver. While cutaneous melanoma is very sensitive to immunotherapy, UM is known to be less responsive and patients were excluded from pivotal clinical trials. To date, there is no standard first line therapy for metastatic UM and clinical trial participation is encouraged. While UM is considered a radio-resistant tumor, there is a role for radiotherapy (RT) as palliative treatment and possibly for immune sensitization. This a retrospective analysis aimed at addressing the role of combination checkpoint inhibitors (ICI) with RT as a synergistic treatment in metastatic UM patient. We hypothesized that concurrent RT would improve the clinical response to immunotherapy. Retrospective chart review of patients with metastatic UM treated with ICI at Ella Lemelbaum Institute between 2015 and 2021. Patients' electronic medical records were analyzed for baseline characteristics, response rate and survival data. Patients were grouped according to receipt of concomitant RT. Study was approved by local IRB and statistical analyses done using Stata V.17. Thirty-nine patients were treated with immunotherapy. Fifty percent were treated with anti-programmed cell death (PD)-1 and 50% with anti-PD1- anti CTLA4 combination therapy. Nine patients were treated concomitantly with immunotherapy and external beam RT or with stereotactic body RT (group A) and 29 patients were treated with immunotherapy alone (group B). Overall response rate was significantly higher in group A (44% versus 10%, p = 0.004). Median progression-free survival was longer for patients in group A (22 months versus 3 m, Hazard Ratio (HR) = 0.37, p = 0.036). Median overall survival was also longer for group A (26 months versus 7.5 m, HR = 0.34, p = 0.03). Toxicity was comparable between the groups. RT may improve response to immunotherapy with ICI in metastatic UM patients and may confer an advantage in survival. Further prospective, larger studies are warranted.

Immediate results of treatment of patients with metastatic uveal melanoma using isolated liver chemoperfusion. The first domestic experience

Introduction. Uveal melanoma is the most common primary intraocular tumor in adults. Despite some achievements in primary tumor treatment, 50% of patients develop distant metastases in various times (3 years to decades). Hematogenous spread is typical for uveal melanoma, and in 90% of the cases liver is the target. Median survival of patients with liver metastases is 4 to 9 months according to various researchers. And the result of treatment is extremely poor, unlike the results of skin melanoma treatment.The aim is to evaluate the immediate results of treatment of patients with uveal melanoma metastatic to the liver using isolated hepatic perfusion technique.Materials and methods. Considering a high risk of developing a metastatic liver disease in patients with uveal melanoma, local therapy is particularly interesting. This article describes the results of 10 metastatic uveal melanoma patients’ Isolated Hepatic Perfusion (IHP) Treatment. IHP was conducted using the standard methods with 100 mg of Melphalan for 60 min.Results and discussion. IHP treatment shows low complication rate. The data for response assessment is available on 9 out of 10 patients, because 10th patient received this treatment less than a month ago. Follow-ups a month after 9 patients underwent IHP showed an objective response to treatment in 6 patients (complete response in 1, partial response in 5 patients).Conclusion. The use of isolated liver chemoperfusion in a small group of patients according to the standard procedure allowed achieving an immediate response in 67% of cases.

The long non-coding RNA SAMMSON is essential for uveal melanoma cell survival

Long non-coding RNAs (lncRNAs) can exhibit cell-type and cancer-type specific expression profiles, making them highly attractive as therapeutic targets. Pan-cancer RNA sequencing data revealed broad expression of the SAMMSON lncRNA in uveal melanoma (UM), the most common primary intraocular malignancy in adults. Currently, there are no effective treatments for UM patients with metastatic disease, resulting in a median survival time of 6–12 months. We aimed to investigate the therapeutic potential of SAMMSON inhibition in UM. Antisense oligonucleotide (ASO)-mediated SAMMSON inhibition impaired the growth and viability of a genetically diverse panel of uveal melanoma cell lines. These effects were accompanied by an induction of apoptosis and were recapitulated in two uveal melanoma patient derived xenograft (PDX) models through subcutaneous ASO delivery. SAMMSON pulldown revealed several candidate interaction partners, including various proteins involved in mitochondrial translation. Consequently, inhibition of SAMMSON impaired global, mitochondrial and cytosolic protein translation levels and mitochondrial function in uveal melanoma cells. The present study demonstrates that SAMMSON expression is essential for uveal melanoma cell survival. ASO-mediated silencing of SAMMSON may provide an effective treatment strategy to treat primary and metastatic uveal melanoma patients.

1772P Demonstration of T cell redirection and immune activation in skin rash following tebentafusp treatment

Tebentafusp (tebe) is an investigational TCR–anti-CD3 bispecific fusion protein that targets gp100 and activates T cells. In a recent phase 3 study, tebe improved overall survival (OS) in metastatic uveal melanoma patients (pts)1. Most pts developed skin rash after dose 1, an expected adverse event since melanocytes also express gp100; however, rash was not an independent predictor of OS benefit2. 12/14 pts developed >1 grade rash within 7 days post 1st dose. Paired skin biopsies from pts with metastatic melanoma (NCT01211262) were collected pre and post the 1st (N=12) or 4th (N=2) dose of tebe. Fixed samples were assessed by hematoxylin and eosin and CD3 immunohistochemistry (IHC). On 5 additional skin biopsies, dual IHC for Melan-A and CD4/8 was performed. RNAlater® samples were analyzed by RNAseq. Differential gene expression, pathway and cell type composition analysis were performed using R software. Biopsies from these pts showed increase in lymphocytic infiltrate, exocytosis of lymphocytes and basal cell vacuolization (p=0.002) along the dermo-epidermal junction (DEJ) and upper dermal perivascular inflammatory infiltrate (p=0.01) post treatment compared to baseline. The DEJ inflammatory infiltrate consisted of CD3+ T cells, which were predominantly CD8+ and localized close to melanocytes. RNAseq identified 1786 differentially expressed genes (threshold: p-adj≤0.05, log2-ratio≥0.75), with enrichment of innate and adaptive pathways, including IFNγ signaling, post treatment compared to baseline (p-adj<10-17). An increase in macrophage and CD8+ T cell genes was accompanied by upregulation of the cytotoxic genes GZMB and PRF1 (p-adj<10-6). Chemokines CXCL9/10/11 and cytokines IL-10/15/32 were overexpressed (p-adj<10-7). Expression of melanocyte markers, PMEL, MLANA and DCT were decreased. Tebe induced rapid recruitment of T cells in the proximity of intraepidermal melanocytes in addition to macrophage activation. Thus tebe-induced skin rash is an on-target effect and may be an important pharmacodynamic tool to better understand the precise molecular and cellular cascades of T cell redirection in the tumor. 1Piperno-Neumann S. AACR 2021 CT002. 2Hassel J. ASCO 2021 #9527.

27995 Evaluation of the modified immune prognostic index to prognosticate outcomes in metastatic uveal melanoma patients treated with immune checkpoint inhibitors

Background: Metastatic uveal melanoma (MUM) is associated with poor overall survival (OS) and inferior response to immune checkpoint inhibitor (ICI) therapy when compared with metastatic cutaneous melanoma. MUM-specific data to guide treatment is limited, and prognostic biomarkers are lacking.

The Analysis of Inflammation-Related Proteins in a Cargo of Exosomes Derived from the Serum of Uveal Melanoma Patients Reveals Potential Biomarkers of Disease Progression.

Simple SummaryUveal melanoma (UM) is the most common intraocular tumour in adults with a poor prognosis and extremely high mortality rate due to the development of metastatic disease. Despite good knowledge of the histological and genetic background of metastases formation, there is still a lack of specific biomarkers which would allow early detection of UM progression. Due to their unique molecular cargo consisting of proteins and nucleic acids, exosomes have been widely studied as carriers of biomarkers for cancer development and progression. In this study, we analyzed the inflammation-related protein cargo of exosomes derived from the serum of primary and metastatic UM patients and healthy donors using multiplex immunoassay technology. We showed a significant correlation between the disease stage and the concentration of inflammation-related proteins from exosomal cargo. Based on the obtained results, we propose the panel of exosomal proteins for early detection of uveal melanoma progression into metastatic disease.Background: Uveal melanoma (UM) is the most common intraocular tumour in adults with a poor prognosis and extremely high mortality rate due to the development of metastatic disease. However, despite relatively good knowledge about the histological and genetic risk factors for metastasis development, there is no specific biomarker that would allow early detection of UM progression. Recently, exosomes and their molecular cargo have been widely studied in the search for potential biomarkers in several cancers. The purpose of this study was to analyze the inflammation-related protein cargo of exosomes derived from the serum of primary and metastatic UM patients and healthy donors. Methods: The exosomes were isolated from the serum of primary and metastatic UM patients and healthy donors. Using multiplex immunoassay technology, we analyzed the concentration of 37 inflammation-related proteins in obtained exosomes. Results: The analysis of protein cargo showed several molecules related to inflammation, such as interferon-gamma, interleukin 2, 22 and 12(p40), Pentraxin-3, TNFSF13B and TNFSF8 which were significantly enriched in metastatic UM exosomes. We showed a significant correlation between the disease stage and the concentration of these inflammation-related proteins from exosomal cargo. Conclusions: Based on the obtained results, we propose the panel of exosomal proteins for early detection of uveal melanoma progression into metastatic disease.