Purpose Uveal melanoma (UM) is a rare melanoma variant with no effective therapies once metastases develop. Although durable cancer regression can be achieved in metastatic cutaneous melanoma (CM) with immunotherapies that augment naturally existing anti-tumor T cell responses, the role of these treatments for metastatic UM remains unclear. We sought to define the relative immunogenicity of these two melanoma variants and determine whether endogenous anti-tumor immune responses exist against UM. Experimental Design We surgically procured liver metastases from UM (n=16) and CM (n=35) patients and compared the attributes of their respective tumor cell populations and their infiltrating T cells (TIL) using clinical radiology, histopathology, immune assays and whole exomic sequencing. Results Despite having common melanocytic lineage, UM and CM metastases differed in their melanin content, tumor differentiation antigen expression, and somatic mutational profile. Immunologic analysis of TIL cultures expanded from these divergent forms of melanoma revealed CM TIL were predominantly composed of CD8+ T cells, while UM TIL were CD4+ dominant. Reactivity against autologous tumor was significantly greater in CM TIL compared to UM TIL. However, we identified TIL from a subset of UM patients which had robust anti-tumor reactivity comparable in magnitude to CM TIL. Interestingly, the absence of melanin pigmentation in the parental tumor strongly correlated with the generation of highly reactive UM TIL. Conclusions The discovery of this immunogenic group of UM metastases should prompt clinical efforts to determine whether patients who harbor these unique tumors can benefit from immunotherapies that exploit endogenous anti-tumor T cell populations.

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Background: Longer time from diagnosis to definitive surgery (TTDS) is associated with increased melanoma-specific mortality. Although black patients present with later-stage melanoma and have worse survival than non-Hispanic white patients, the association between race and TTDS is unknown.Objective: To investigate racial differences in time to melanoma treatment.Methods: Retrospective review of the National Cancer Database (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015). Multivariable logistic regression was used to evaluate the association of race with TTDS, controlling for sociodemographic/ disease characteristics.Results: Of the 233,982 patients with melanoma identified, 1221 (0.52%) were black. Black patients had longer TTDS for stage I to III melanoma (P \.001) and time to immunotherapy (P = .01), but not for TTDS for stage IV melanoma or time to chemotherapy (P [.05 for both). When sociodemographic characteristics were controlled for, black patients had over twice the odds of having a TTDS between 41 and 60 days, over 3 times the odds of having a TTDS between 61 and 90 days, and over 5 times the odds of having a TTDS over 90 days. Racial differences in TTDS persisted within each insurance type. Patients with Medicaid had the longest TTDS (mean, 60.4 days), and those with private insurance had the shortest TTDS (mean, 44.6 days; P \ .001 for both).Conclusions: Targeted approaches to improve TTDS for black patients are integral in reducing racial disparities in melanoma outcomes.

Nutrient-deprived conditions in the tumor microenvironment (TME) restrain cancer cell viability due to increased free radicals and reduced energy production. In pancreatic cancer cells a cytosolic metabolic enzyme, wild-type isocitrate dehydrogenase 1 (wtIDH1), enables adaptation to these conditions. Under nutrient starvation, wtIDH1 oxidizes isocitrate to generate α-ketoglutarate (αKG) for anaplerosis and NADPH to support antioxidant defense. In this study, we show that allosteric inhibitors of mutant IDH1 (mIDH1) are potent wtIDH1 inhibitors under conditions present in the TME. We demonstrate that low magnesium levels facilitate allosteric inhibition of wtIDH1, which is lethal to cancer cells when nutrients are limited. Furthermore, the Food & Drug Administration (FDA)-approved mIDH1 inhibitor ivosidenib (AG-120) dramatically inhibited tumor growth in preclinical models of pancreatic cancer, highlighting this approach as a potential therapeutic strategy against wild-type IDH1 cancers.

Purpose Adoptive transfer of autologous tumor infiltrating lymphocytes (TIL) can mediate durable cancer regression in selected patients with metastatic melanoma. However, the tumor antigens associated with these favorable responses remain unclear. We hypothesized that a clinical strategy involving the iterative adoptive transfer of selected autologous antigen specific T cell clones could help systematically define immunologic targets associated with successful cancer therapy, without the interpretative ambiguity of transferring polyclonal populations. Here, we evaluated the clinical efficacy of CD8+ T cell clones specific for the melanocyte differentiation antigens (MDA), gp100 and MART-1, respectively. Experimental Design We conducted two consecutive phase II clinical trials involving the adoptive transfer of highly selected autologous antigen specific CD8+ T cell clones against gp100 and MART-1, respectively. Fifteen HLA-A2+ treatment-refractory metastatic melanoma patients received highly avid MDA specific CD8+ T cell clones specific for either gp100 (n=10) or MART-1 (n=5) with or without intravenous interleukin-2 after a lymphodepleting myeloablative preparative regimen. Results Of the fifteen treated patients, we observed immune mediated targeting of skin melanocytes in eleven patients (73%) and clonal engraftment in eight patients (53%) after cell transfer. There were only transient minor tumor regressions observed, but no objective tumor responses based upon RECIST criteria. Conclusions Despite successful clonal repopulation and evidence of in vivo antigen targeting, the poor therapeutic efficacy after the adoptive transfer of autologous MDA specific T cells raises significant concerns regarding future immunotherapy efforts targeting this class of tumor antigens.

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The optimal T cell attributes for adoptive cancer immunotherapy are unclear. Recent clinical trials of ex vivo expanded tumor-infiltrating lymphocytes indicated that differentiated T effector cells can elicit durable anti-tumor responses in some cancer patients, with their anti-tumor activity tightly correlated with their persistence in the host. Thus, there is great interest in the definition of intrinsic biomarkers that can predict the conversion of short-lived tumor antigen-specific T effector cells into long-lived T memory cells. Long-term persistence of ex vivo expanded tumor specific CD8+ T effector clones has been reported in refractory metastatic melanoma patients after adoptive T cell transfer. By utilizing highly homogeneous clone populations from these preparations, we performed a comparative transcriptional profiling to define pre-infusion molecular attributes that can be ascribed to an effector-to-memory transition. Through this route, we discovered that pre-infusion T cell clones which expressed the IL-7 receptor (IL-7R) and c-myc were more likely to persist longer after adoptive transfer to patients. The predictive value of these two biomarkers was strengthened by utilizing IL-7R protein, IL-7 induced pSTAT5, and c-myc mRNA expression to prospectively identify human tumor-specific T effector clones capable of engraftment into immunodeficient mice. Overall, our findings reveal IL-7R and c-myc expression as intrinsic biomarkers that can predict the fate of effector CD8+ T cells after adoptive transfer.