Treatment Of Metastatic Uveal Melanoma Research Articles

Development and optimization of orthotopic liver metastasis xenograft mouse models in uveal melanoma

BackgroundPatients with metastatic uveal melanoma (MUM) in the liver usually die within 1 year. The development of new treatments for MUM has been limited by the lack of diverse MUM cell lines and appropriate animal models. We previously reported that orthotopic xenograft mouse models established by direct injection of MUM cells into the liver were useful for the analysis associated with tumor microenvironment in the liver. However, considering that patients with UM metastasize to the liver hematogenously, direct liver injection model might not be suitable for investigation on various mechanisms of liver metastasis. Here, we aim to establish new orthotopic xenograft models via hematogenous dissemination of tumor cells to the liver, and to compare their characteristics with the hepatic injection model. We also determine if hepatic tumors could be effectively monitored with non-invasive live imaging.MethodstdtTomate-labeled, patient-derived MUM cells were injected into the liver, spleen or tail vein of immunodeficient NSG mice. Tumor growth was serially assessed with In Vivo Imaging System (IVIS) images once every week. Established hepatic tumors were evaluated with CT scan and then analyzed histologically.ResultsWe found that splenic injection could consistently establish hepatic tumors. Non-invasive imaging showed that the splenic injection model had more consistent and stronger fluorescent intensity compared to the hepatic injection model. There were no significant differences in tumor growth between splenic injection with splenectomy and without splenectomy. The splenic injection established hepatic tumors diffusely throughout the liver, while the hepatic injection of tumor cells established a single localized tumor. Long-term monitoring of tumor development showed that tumor growth, tumor distribution in the liver, and overall survival depended on the number of tumor cells injected to the spleen.ConclusionWe established a new orthotopic hepatic metastatic xenograft mouse model by splenic injection of MUM cells. The growth of orthotopic hepatic tumors could be monitored with non-invasive IVIS imaging. Moreover, we evaluated the therapeutic effect of a MEK inhibitor by using this model. Our findings suggest that our new orthotopic liver metastatic mouse model may be useful for preclinical drug screening experiments and for the analysis of liver metastasis mechanisms.

Palliative Endoscopic Treatment of Metastatic Uveal Melanoma to the Upper and Lower Urinary Tract

We report a rare case of uveal melanoma demonstrating simultaneous metastatic foci to the upper and lower urinary tract. A 60-year-old woman, with metastatic uveal melanoma, was referred for incidental right hydronephrosis. Diagnostic cystoscopy and ureteroscopy confirmed the diagnosis of metastatic malignant melanoma to the bladder and kidney. Both tumor resection and coagulation were possible with the neodymium/holmium laser combination. The goals of treatment in metastatic patients should be cessation of hematuria and relief of obstruction with preservation of functional renal reserve while minimizing morbidity.

An Outcome Assessment of a Single Institution's Longitudinal Experience with Uveal Melanoma Patients with Liver Metastasis.

There is no FDA-approved treatment for metastatic uveal melanoma (UM) and overall outcomes are generally poor for those who develop liver metastasis. We performed a retrospective single-institution chart review on consecutive series of UM patients with liver metastasis who were treated at Thomas Jefferson University Hospital between 1971–1993 (Cohort 1, n = 80), 1998–2007 (Cohort 2, n = 198), and 2008–2017 (Cohort 3, n = 452). In total, 70% of patients in Cohort 1 received only systemic therapies as their treatment modality for liver metastasis, while 98% of patients in Cohort 2 and Cohort 3 received liver-directed treatment either alone or with systemic therapy. Median Mets-to-Death OS was shortest in Cohort 1 (5.3 months, 95% CI: 4.2–7.0), longer in Cohort 2 (13.6 months, 95% CI: 12.2–16.6) and longest in Cohort 3 (17.8 months, 95% CI: 16.6–19.4). Median Eye Tx-to-Death OS was shortest in Cohort 1 (40.8 months, 95% CI: 37.1–56.9), and similar in Cohort 2 (62.6 months, 95% CI: 54.6–71.5) and Cohort 3 (59.4 months, 95% CI: 56.2–64.7). It is speculated that this could be due to the shift of treatment modalities from DTIC-based chemotherapy to liver-directed therapies. Combination of liver-directed and newly developed systemic treatments may further improve the survival of these patients.

Synthetic Lethal Screen to Identify Molecular Mechanisms that Drive Uveal Melanoma

Melanoma that strikes the uveal cells of the eye represents about 5% of all melanoma cases. Uveal melanoma is a highly aggressive form of cancer that exhibits a propensity to metastasize to the liver. At this time there are no effective treatments for metastatic uveal melanoma and new therapeutic strategies are urgently needed. The majority of uveal melanomas are derived from early activating mutations in the G-proteins GNA11 or GNAQ. In order to further explore and identify molecular mechanisms that uveal melanoma cell lines rely upon for proliferation and survival, we will perform CRISPR/Cas9 mediated synthetic lethality screening. To accomplish this, we will generate a uveal melanoma cell line 92.1 that expresses the endonuclease Cas9 and introduce a guide RNA library into it that targets the functional domains of epigenetic regulator proteins. Thus, we will be able to determine which epigenetic regulator genes are required for the survival and proliferation of these cells by measuring which guide RNAs "drop out" over time. The guide RNAs that drop out likely disrupt essential genes that the cell relies on for growth. Cells carrying these gRNAs are consequently depleted from the culture. This will indicate that Cas9 mediated disruption of the gene targeted by that guide RNA causes cell death and will therefore identify the key dependencies of the uveal melanoma cells. We expect that the results of these experiments will reveal novel genetic mechanisms characteristic of GNAQ mutant uveal melanoma cells which could be therapeutically targeted in the future.

Multi-Platform Omics Analysis for Identification of Molecular Characteristics and Therapeutic Targets of Uveal Melanoma

Currently, there is no effective treatment for metastatic uveal melanoma (UVM). Here, we aimed to identify the mechanism involving intrinsic chemoresistance of metastatic UVM and the relevant therapeutic targets for UVM. We analyzed cohorts of 80 and 67 patients with primary UVM and skin cutaneous melanoma (SKCM), respectively, using The Cancer Genome Atlas dataset. Mutational burdens identified by whole exome sequencing were significantly lower in UVM than in SKCM patients. COSMIC mutational signature analysis identified that most of the mutations in UVM patients (>90%) were associated with spontaneous deamination of 5-methylcytosine or defective mismatch repair. Transcriptome analysis revealed that the MYC signature was more enriched in UVM patients, as compared to SKCM patients. Fifty-nine (73.8%) of 80 UVM patients showed gains in MYC copy number, and a high MYC copy number was associated with aggressive clinicopathological features of tumors and poor survival. Kinome-wide siRNA library screening identified several therapeutic targets, reported as synthetic lethal targets for MYC-addicted cancers. Notably, UVM cell lines showed high susceptibility to a WEE1 inhibitor (MK-1775; adavosertib) at a clinically tolerable dose. Overall, our study identified high MYC activity in UVM, and suggested G2/M checkpoint inhibitors as effective therapeutic targets for UVM.

A Phase I Study of Percutaneous Oncolytic Rose Bengal Disodium for Metastatic Uveal Melanoma Patients with Hepatic Metastases: A Single-Center Cohort Summary

Abstract Background Rose bengal disodium (PV-10) is a small molecule oncolytic immunotherapy in clinical development for treatment of solid tumors. When administered by intralesional injection, PV-10 can produce an immunogenic cell death that may induce a T-cell mediated immune response against treatment-refractory and immunologically-cold tumors. Given this mechanism of action, we investigated treatment of metastatic uveal melanoma with percutaneous hepatic PV-10. Methods PV-10-LC-01 (NCT00986661) is an open-label phase I basket study evaluating the safety, tolerability, and preliminary efficacy of intralesional PV-10 in patients with solid tumors metastatic to the liver. Percutaneous injections of PV-10 are administered to one or more designated hepatic tumor(s) with a maximum sum of diameters £4.9 cm. Response assessments using 2D EASL criteria are performed at Day 28, then every 3 months. Patients with additional injectable tumors may receive further PV-10 after Day 28. Eligible patients may receive standard of care checkpoint blockade immunotherapy during treatment with PV-10. Results In a single-center cohort of uveal melanoma patients with hepatic metastases, to date, the study has screened 15 patients with metastatic uveal melanoma; eleven patients have been consented, enrolled, and received at least one PV-10 treatment cycle; five have received a second treatment with intralesional PV-10 for a total of 18 injected hepatic tumors. Three patients have received PV-10 with initiation of standard of care checkpoint blockade. One patient was on immunotherapy prior to PV-10 treatment. In 11 injected tumors with response assessment, the objective response rate has been 36%. Toxicities have been self-limiting and consistent with established patterns, including photosensitivity, pink urine, and transaminitis that resolved in Conclusion Percutaneous PV-10 exhibited acceptable safety and tolerability with encouraging evidence of activity in injected lesions. Updated enrollment as well as safety and efficacy data of the uveal melanoma cohort will be presented at the meeting. Clinical trial identification NCT00986661. Legal entity responsible for the study Provectus. Funding Provectus. Disclosure S. Patel: Research grant / Funding (institution): Bristol-Myers Squibb; Advisory / Consultancy: Cardinal Health; Advisory / Consultancy: Castle Biosciences; Leadership role, Data Safety Monitoring Board Chair: Immunocore; Advisory / Consultancy: Incyte; Honoraria (self): Merck; Research grant / Funding (institution): Novartis; Research grant / Funding (institution): Provectus; Leadership role, Research grant / Funding (institution), Data Safety Monitoring Board chair: Reata. E.A. Wachter: Shareholder / Stockholder / Stock options, Full / Part-time employment: Provectus. All other authors have declared no conflicts of interest.

Infectious Knockdown of CREB and HIF-1 for the Treatment of Metastatic Uveal Melanoma.

Uveal melanoma (UM) is the most prevalent primary intraocular cancer in adults. Up to half the patients develop metastases that are currently incurable, and most patients die within two years following the diagnosis of metastases. Therefore, novel therapeutic approaches are required. It has been established that tumor cells are more resistant to the hypoxia cue than non-malignant cells and can remain viable in hypoxia. Oxygen absence in hypoxic tumor areas means the absence of chemotherapeutics and the absence of the effector for radiotherapy (free oxygen radicals). To overcome this treatment resistance, we constructed MuLV-based replication-competent retroviral (RCR) vectors expressing shRNA targeting the hypoxia-response regulating genes CREB and HIF-1. These RCRs express shRNAs either against a single exon or against an exon and the poly-A signal to minimize the point-mutation resistance. These RCRs that only infect replicating cells will preferentially infect tumor cells. Pre-infected Mel270 UM subcutaneous xenografts in SCID mice were monitored weekly in vivo via bioluminescence. Here, we demonstrate that the knockdown of CREB or HIF-1 in UM cells dramatically decreases UM tumor progression. The reduction of the expression of Glut-1, which is a major glucose transporter in cancer cells, within tumors that are infected with the armed viruses may indicate UM’s dependence on glycolysis for tumor progression.

Immunotherapies for the Treatment of Uveal Melanoma-History and Future.

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

Pembrolizumab as first-line treatment for metastatic uveal melanoma

BackgroundNo standard treatment has been defined for metastatic uveal melanoma (mUM). Although clinical trials testing Nivolumab/Pembrolizumab for cutaneous melanoma did not include mUM, anti PD-1 agents are commonly used for this disease.Patients and methodsIn this prospective observational cohort single arm study, we investigated efficacy and safety of Pembrolizumab as first-line therapy for mUM. The efficacy was evaluated in terms of progression-free survival (PFS), response rate and overall survival (OS). Toxicity was also assessed.ResultsSeventeen patients were enrolled. A median of 8 cycles were administered (range 2–28). Two patients achieved partial response (11.7%), 6 a disease stabilization (35.3%), whereas 9 (53%) had a progression. No complete response was observed. PFS of the overall population was 3.8 months. PFS was 9.7 months for patients with an interval higher than 5 years from diagnosis of primary tumor to metastatic disease and 2.6 months for patients with an interval lower than 5 years [p = 0.039, HR 0.2865 (95% CI 0.0869–0.9443)]. Median OS was not reached. The two responding patients were still on treatment with Pembrolizumab at the time of data analysis. Survival was 12.8 months for patients with clinical benefit, while OS for progressive patients was 3.1 months. PD-L1 expression and genomic abnormalities predictive of relapse after diagnosis of primary tumor were not associated with PFS. Toxicity was mild, without grade 3–4 side effects.ConclusionsThe efficacy of Pembrolizumab does not seem particularly different when compared to other agents for mUM, but responding patients had a remarkable disease control.

Uveal melanoma: physiopathology and new in situ-specific therapies.

Uveal melanoma is the most common primary intraocular tumor in adults. It can arise from melanocytes in the anterior (iris) or posterior uveal tract (choroid and ciliary body). Uveal melanoma has a particular molecular pathogenesis, being characterized by specific chromosome alterations and gene mutations (e.g., GNAQ/GNA11; BAP1), which are considered promising targets for molecular therapy. Primary treatment of uveal melanoma includes radiotherapy (brachytherapy and charged-particle therapy), phototherapy (photocoagulation, transpupillary thermal therapy, and photodynamic therapy) and surgery (local resection, enucleation and exenteration). Approximately half of patients with uveal melanoma will, however, develop metastasis, especially in the liver. The treatment of metastatic uveal melanoma includes systemic chemotherapy, immunotherapy and molecular targeted therapy. Liver-directed therapies, such as resection, chemoembolization, immunoembolization, radioembolization, isolated hepatic perfusion and percutaneous hepatic perfusion, are also available to treat metastatic uveal melanoma. Several clinical trials are being developed to study new therapeutic options to treat uveal melanoma, mainly for those with identified liver metastases. The present work discusses the physiopathology and new in situ-specific therapies for the treatment of uveal melanoma.

Overall survival after treatment for metastatic uveal melanoma: a systematic review and meta-analysis.

The overall survival (OS) of patients with metastatic uveal melanoma is short, the evidence for effectiveness of treatments is limited, and no consensus on the choice of treatment exists. We aimed to advance interpretation of OS as an outcome by pooling peer-reviewed data. The design is a systematic review and meta-analysis. We searched PubMed from 1 January 1980, to 29 March 2017, for articles reporting patient-level survival in Kaplan-Meier or numerical form. We digitized survival graphs, pooled individual survival times, calculated median OS by treatment modality, and compared each modality by the log-rank test and Cox regression using conventional chemotherapy (CHT) as a reference. Individual-level data were obtained from 78 articles with 2494 patients. The median OS across all treatment modalities was 1.07 years (range: 0.59-2.50 years). Pooled OS reported after isolated hepatic perfusion [median OS: 1.34 years; hazard ratio (HR): 0.92, 95% confidence interval (CI): 0.87-0.97, P = 0.0040], immunoembolization (median OS: 1.63; HR: 0.97, 95% CI: 0.95-1.00, P = 0.0080), and surgery (median OS: 1.43; HR: 0.94, 95% CI: 0.92-0.96, P < 0.0001) was longer, and after checkpoint inhibitor shorter (median OS: 0.59; HR: 1.13, 95% CI: 1.06-1.20, P < 0.0001) than after CHT (median OS: 0.91 years), but subject to identifiable confounding factors. OS following other modalities did not differ from CHT. Reported OS was unassociated with the decade of publication, but depended on the percentage of first-line treated patients. Our results suggest no clinically significant difference in OS by treatment modality or decade. Most of the difference in reported OS likely is attributable to surveillance, selection, and publication bias rather than treatment-related prolongation. Our pooled data provide benchmarks for future trials.

1271P - Retrospective analysis of the treatment of metastatic uveal melanoma comparing systemic chemotherapy and transarterial chemoembolization

1271P - Retrospective analysis of the treatment of metastatic uveal melanoma comparing systemic chemotherapy and transarterial chemoembolization

Abstract 5157: ARF6 controls WNT5A receptor internalization to promote uveal melanoma invasion and metastasis

Abstract Introduction: Uveal melanoma is the most common primary ocular malignancy and there is currently no effective treatment for metastatic uveal melanoma largely because of the lack of understanding of the molecular mechanisms underlying this cancer. Although activating oncogenic mutations in GNAQ and GNA11 are present in 95% of uveal melanoma tumors, virtually nothing is known about the molecular mechanisms that drive oncogenesis in the remaining 5% of uveal melanomas that possess only wild type Gαq alleles and the molecular and cellular mechanisms that promote metastasis have not yet been discovered. This latter deficit in knowledge is extremely vexing, given that metastatic disease causes death in most uveal melanoma patients. We have recently shown that ADP-ribosylation factor 6 (ARF6), a small GTPase, is an immediate downstream effector of oncogenic Gαq and controls the entire major signaling pathways known to drive Gαq-mediated tumor formation and growth in uveal melanoma cells that have an activating mutation in Gαq. Moreover, in cutaneous melanoma, stimulation of the receptor by WNT5A activates ARF6 and controls metastasis via the release of β-catenin from N-cadherin and β-catenin's subsequent nuclear transport. Previous studies have also demonstrated that ARF6 plays a role in the internalization of various classes of membrane receptors including receptor tyrosine kinase (RTK) and G protein coupled receptor (GPCR) to control signal transduction, and WNT5A and its receptor promote tumor invasion and metastasis via receptor internalization in human cancers. Based on these intriguing findings, we postulate that ARF6 might be functioning to control tumor invasion and metastasis in uveal melanomas. Experimental Procedures: To test our hypothesis, we conducted cell invasion assays on uveal melanoma cell lines while targeting ARF6 expression by siRNA or ARF6 activity by pharmacological inhibition. We then proceeded with cell fractionation to look for any differences in the properties of subcellular components in treated cells compared to untreated cells. Unpublished findings: Here we show that WNT5A is expressed at high levels in Gαq wild type uveal melanoma cells and that WNT5A activates ARF6 through ROR2 receptor. When we block ARF6 expression by knockdown or ARF6 activity with a small molecule inhibitor, uveal melanoma invasion is significantly reduced. Notably, ARF6 is necessary for WNT5A-mediated ROR2 internalization. Conclusions: This work indicates that ARF6 functions in the internalization of WNT5A receptor to activate the signaling pathways that drive invasion and metastasis in uveal melanoma. These results would suggest that targeting ARF6 activation might be an effective therapy for the treatment of all uveal melanomas, regardless of their mutational status for Gαq. Citation Format: Donghan Shin, Coulson P. Rich, Lehi Acosta, Jackson R. Richards, Jae Hyuk Yoo, Allie H. Grossmann, Zongzhong Tong, Alan L. Mueller, Weiquan Zhu, Dean Y. Li, Shannon J. Odelberg. ARF6 controls WNT5A receptor internalization to promote uveal melanoma invasion and metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5157.

Treatment of metastatic uveal melanoma (mUM) directed by a comprehensive molecular tumour analysis program (CMTA).

9566Background: There is a lack of active treatment against mUM. Such “hard-to-treat” tumour might benefit from treatment decisions driven by a complete genomic and transcriptomic analysis program....

Uveal Melanoma: A Review of the Literature.

Melanomas affecting different components of the uvea occur with differing frequencies and clinical presentations. Uveal melanoma is diagnosed via funduscopic exam and ancillary tests. These lesions may present with visual findings or incidental findings on physical exam. Metastasis occurs in approximately half of all patients with primary uveal melanoma. The liver is the most common site of metastasis. Enucleation was at one time considered the definitive local treatment for primary uveal melanoma, but has been largely replaced by other therapeutic procedures that aim to prevent metastasis while preserving vision. Unfortunately, metastasis of uveal melanoma almost always proves to be fatal. The current treatment of metastatic uveal melanoma is limited by the intrinsic resistance of uveal melanoma to conventional systemic therapies. Advancements in molecular biology have resulted in the identification of a number of promising prognostic and therapeutic targets. Early detection and therapy are important factors in disease survival. It is imperative that the treating physician be familiar with the clinical features of uveal melanoma and distinguish it from mimickers in order to ensure effective and timely treatment.

1218PD - Precision medicine for the treatment of metastatic uveal melanoma: A pilot study

1218PD - Precision medicine for the treatment of metastatic uveal melanoma: A pilot study

Recent advances in uveal melanoma treatment.

Uveal melanoma (UM) is the most common primary intraocular malignancy in adults. Recent advances in the understanding of molecular characteristics helped to determine which tumors are most likely to progress. About 50% of patients carrying genetic alterations such as chromosomal aberrations and mutations are at significant risk for metastatic disease of which the majority will succumb to UM within few months. Currently, there is no effective treatment for metastatic uveal melanoma, and we hope this review will encourage researchers and clinicians to work to find a better standard of care. In this article we provide a comprehensive overview of the molecular framework of UM, highlighting the most common mutations involved in this kind of cancer. It also covers the most recent treatments from basic research to clinical trials, including small molecules, nucleic acids or immunotherapy, among others. It is intended to serve as a key reference for clinicians and researchers working in this field.

Inflammatory cell infiltrates in advanced metastatic uveal melanoma

Current treatments for metastatic uveal melanoma (mUM) are limited and rarely prolong patient survival. Immunotherapy trials for mUM are few and to date have demonstrated only marginal success. High densities of tumor-associated macrophages (TAMs) and infiltrating T lymphocytes (TILs) in primary UM are associated with poor prognosis. Little is known about the immune microenvironment of mUM. Our aim was to examine the presence and distribution of TAMs and TILs in mUM within the liver. Whole-tissue sections of liver mUM (n=35) were examined by immunohistochemistry. For TAMs, monoclonal antibodies against CD68 and CD163 were used. Macrophage density and morphology were scored using previous established systems. Density and spatial distribution of TILs were highlighted using antibodies against CD3 (pan-lymphocyte marker), CD4 (T-helper cells), and CD8 (T-cytotoxic cells). CD68+ and CD163+ TAMs were seen within the tumor in all 35 specimens; their density was "moderate" in 50% of cases and "few" in 43%, and the majority showed an "indeterminate" phenotype. CD3+ TILs were noted both within mUMs and surrounding the tumor. Of these, CD8+ TILs were "few" in number within mUM but were predominantly seen peritumorally at the tumor/normal liver interface, whereas CD4+ TILs showed a high perivascular density within mUM. CD68+ and CD163+ TAMs of "indeterminate" morphology were observed in mUM, suggesting a tendency toward the protumorigenic M2 phenotype. CD4+ TILs were seen within the mUM, whereas CD8+ TILs tended to be peritumoral. The biological and functional roles of inflammatory cells in mUM require further investigation to determine if they represent potential targets for future therapies in mUM.

Establishment of an orthotopic patient-derived xenograft mouse model using uveal melanoma hepatic metastasis

BackgroundMetastatic uveal melanoma is a highly fatal disease; most patients die from their hepatic metastasis within 1 year. A major drawback in the development of new treatments for metastatic uveal melanoma is the difficulty in obtaining appropriate cell lines and the lack of appropriate animal models. Patient-derived xenograft (PDX) tumor models, bearing ectopically implanted tumors at a subcutaneous site, have been developed. However, these ectopically implanted PDX models have obstacles to translational research, including a low engraftment rate, slow tumor growth, and biological changes after multiple passages due to the different microenvironment. To overcome these limitations, we developed a new method to directly transplant biopsy specimens to the liver of immunocompromised mice.ResultsBy using two metastatic uveal melanoma cell lines, we demonstrated that the liver provides a more suitable microenvironment for tumor growth compared to subcutaneous sites and that surgical orthotopic implantation (SOI) of tumor pieces allows the creation of a liver tumor in immunocompromised mice. Subsequently, 10 of 12 hepatic metastasis specimens from patients were successfully xenografted into the immunocompromised mice (83.3% success rate) using SOI, including 8 of 10 needle biopsy specimens (80%). Additionally, four cryopreserved PDX tumors were re-implanted to new mice and re-establishment of PDX tumors was confirmed in all four mice. The serially passaged xenograft tumors as well as the re-implanted tumors after cryopreservation were similar to the original patient tumors in histologic, genomic, and proteomic expression profiles. CT imaging was effective for detecting and monitoring PDX tumors in the liver of living mice. The expression of Ki67 in original patient tumors was a predictive factor for implanted tumor growth and the success of serial passages in PDX mice.ConclusionsSurgical orthotopic implantation of hepatic metastasis from uveal melanoma is highly successful in the establishment of orthotopic PDX models, enhancing their practical utility for research applications. By using CT scan, tumor growth can be monitored, which is beneficial to evaluate treatment effects in interventional studies.

A multireferral centre retrospective cohort analysis on the experience in treatment of metastatic uveal melanoma and utilization of sequential liver-directed treatment and immunotherapy

Metastatic uveal melanoma is a rare malignancy with a poor prognosis. To date, systemic therapy has been ineffective; however, there are few data on the benefits of anti-CTLA4 or anti-PD-1 antibodies in sequence with liver-directed therapy. A retrospective cohort analysis was carried out on 37 consecutive patients managed in a tertiary referral centre examining the safety and efficacy of treatment; patterns of care; and impact on survival. The sequential treatment with transarterial chemotherapy (TAC), systemic immunotherapy (IT) and systemic chemotherapy was reviewed. In all, 18 patients in the series received sequential therapy. The median overall survival (OS) was 17 months (n=37), which compared favourably with previously reported series. Patients treated with TAC first or second line had an overall progression-free survival (PFS) of 9 months (n=29) and IT PFS 7 months (n=26). The overall response rate (ORR) for TAC first line was 26% and the disease control rate (DCR) was 65% (n=23). ORR for IT first line was 7%, DCR 77% (n=14). Second-line (cross-over) IT ORR was 16%, DCR 58% (n=12). For second-line (cross-over) TAC, ORR was 50% and DCR was 66% (n=6). Toxicity was manageable. There were no cases of autoimmune hepatitis. In this retrospective small series analysis in uveal melanoma, liver-directed therapy and IT in sequence have shown to be active and reasonably well tolerated. Further prospective clinical trials should clarify the role of these treatments and their potential survival benefit.