Medicine (Austin & Northern Health) - Research Publications
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ItemOptimizing combination dabrafenib and trametinib therapy in BRAF mutation-positive advanced melanoma patients: Guidelines from Australian melanoma medical oncologists(WILEY-BLACKWELL, 2016-12)BRAF mutations occur commonly in metastatic melanomas and inhibition of mutant BRAF and the downstream kinase MEK results in rapid tumor regression and prolonged survival in patients. Combined therapy with BRAF and MEK inhibition improves response rate, progression free survival and overall survival compared with single agent BRAF inhibition, and reduces the skin toxicity that is seen with BRAF inhibitor monotherapy. However, this combination is associated with an increase in other toxicities, particularly drug-related pyrexia, which affects approximately 50% of patients treated with dabrafenib and trametinib (CombiDT). We provide guidance on managing adverse events likely to arise during treatment with combination BRAF and MEK inhibition with CombiDT: pyrexia, skin conditions, fatigue; and discuss management of CombiDT during surgery and radiotherapy. By improving tolerability and in particular preventing unnecessary treatment cessations or reduction in drug exposure, best outcomes can be achieved for patients undergoing CombiDT therapy.
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ItemClinicopathological characteristics associated with BRAFK601E and BRAFL597 mutations in melanoma(WILEY-BLACKWELL, 2016-03)BRAF mutations at codons L597 and K601 occur uncommonly in melanoma. Clinical and pathological associations of these mutations were investigated in a cohort of 1119 patients with known BRAF mutation status. A BRAF mutation was identified in 435 patients; Mutations at L597 and the K601E mutation were seen in 3.4 and 3.2% of these, respectively. K601E melanomas tended to occur in male patients, a median age of 58 yr, were generally found on the trunk (64%) and uncommonly associated with chronically sun-damaged (CSD) skin. BRAF L597 melanomas occurred in older patients (median 66 yr), but were associated with CSD skin (extremities or head and neck location - 73.3%, P = 0.001). Twenty-three percent of patients with V600E- and 43% of patients with K601E-mutant melanomas presented with nodal disease at diagnosis compared to just 14% of patients with BRAF wild-type tumors (P = 0.001 and 0.006, respectively). Overall, these mutations represent a significant minority of BRAF mutations, but have distinct clinicopathological phenotypes and clinical behaviors.
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ItemTracking extracellular vesicle phenotypic changes enables treatment monitoring in melanoma(AMER ASSOC ADVANCEMENT SCIENCE, 2020-02)Monitoring targeted therapy in real time for cancer patients could provide vital information about the development of drug resistance and improve therapeutic outcomes. Extracellular vesicles (EVs) have recently emerged as a promising cancer biomarker, and EV phenotyping shows high potential for monitoring treatment responses. Here, we demonstrate the feasibility of monitoring patient treatment responses based on the plasma EV phenotypic evolution using a multiplex EV phenotype analyzer chip (EPAC). EPAC incorporates the nanomixing-enhanced microchip and the multiplex surface-enhanced Raman scattering (SERS) nanotag system for direct EV phenotyping without EV enrichment. In a preclinical model, we observe the EV phenotypic heterogeneity and different phenotypic responses to the treatment. Furthermore, we successfully detect cancer-specific EV phenotypes from melanoma patient plasma. We longitudinally monitor the EV phenotypic evolution of eight melanoma patients receiving targeted therapy and find specific EV profiles involved in the development of drug resistance, reflecting the potential of EV phenotyping for monitoring treatment responses.
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ItemEffects of epithelial to mesenchymal transition on T cell targeting of melanoma cells.(Frontiers Media SA, 2014)Melanoma cells can switch phenotype in a manner similar to epithelial to mesenchymal transition (EMT). In this perspective article, we address the effects of such phenotype switching on T cell targeting of tumor cells. During the EMT-like switch in phenotype, a concomitant change in expression of multiple tumor antigens occurs. Melanoma cells undergoing EMT escape from killing by T cells specific for antigens whose expression is downregulated by this process. We discuss melanoma antigens whose expression is influenced by EMT. We assess the effect of changes in the expressed tumor antigen repertoire on T-cell mediated tumor recognition and killing. In addition to escape from T cell immunity via changes in antigen expression, mesenchymal-like melanoma cells are generally more resistant to classical chemotherapy and radiotherapy. However, we demonstrate that when targeting antigens whose expression is unaltered during EMT, the capacity of T cells to kill melanoma cell lines in vitro is not influenced by their phenotype. When considering immune therapies such as cancer vaccination, these data suggest escape from T cell killing due to phenotype switching in melanoma could potentially be avoided by careful selection of target antigen.
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ItemPhosphoproteomic analysis of cell-based resistance to BRAF inhibitor therapy in melanoma(FRONTIERS MEDIA SA, 2015-05-15)The treatment of melanoma by targeted inhibition of the mutated kinase BRAF with small molecules only temporarily suppresses metastatic disease. In the face of chemical inhibition tumor plasticity, both innate and adaptive, promotes survival through the biochemical and genetic reconfiguration of cellular pathways that can engage proliferative and migratory systems. To investigate this process, high-resolution mass spectrometry was used to characterize the phosphoproteome of this transition in vitro. A simple and accurate, label-free quantitative method was used to localize and quantitate thousands of phosphorylation events. We also correlated changes in the phosphoproteome with the proteome to more accurately determine changes in the activity of regulatory kinases determined by kinase landscape profiling. The abundance of phosphopeptides with sites that function in cytoskeletal regulation, GTP/GDP exchange, protein kinase C, IGF signaling, and melanosome maturation were highly divergent after transition to a drug resistant phenotype.
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ItemNo Preview AvailablePhase II Study of First-Line Trebananib Plus Sorafenib in Patients with Advanced Hepatocellular Carcinoma(WILEY, 2017-07)LESSONS LEARNED: Trebananib leveraging anti-angiogenic mechanism that is distinct from the classic sorafenib anti-vascular endothelial growth factor inhibition did not demonstrate improved progression-free survival at 4 months in patients with advanced hepatocellular carcinoma (HCC).In support of previously reported high Ang-2 levels' association with poor outcome in HCC for patients, trebananib treatment with lower baseline Ang-2 at study entry was associated with improved overall survival to 22 months and may suggest future studies to be performed within the context of low baseline Ang-2. BACKGROUND: Ang-1 and Ang-2 are angiopoietins thought to promote neovascularization via activation of the Tie-2 angiopoietin receptor. Trebananib sequesters Ang-1 and Ang-2, preventing interaction with the Tie-2 receptor. Trebananib plus sorafenib combination has acceptable toxicity. Elevated Ang-2 levels are associated with poor prognosis in hepatocellular carcinoma (HCC). METHODS: Patients with HCC, Eastern Cooperative Oncology Group ≤2, and Childs-Pugh A received IV trebananib at 10 mg/kg or 15 mg/kg weekly plus sorafenib 400 mg orally twice daily. The study was planned for ≥78% progression-free survival (PFS) rate at 4 months relative to 62% for sorafenib historical control (power = 80% α = 0.20). Secondary endpoints included safety, tolerability, overall survival (OS), and multiple biomarkers, including serum Ang-2. RESULTS: Thirty patients were enrolled sequentially in each of the two nonrandomized cohorts. Demographics were comparable between the two arms and the historical controls. PFS rates at 4 months were 57% and 54% on the 10 mg/kg and 15 mg/kg trebananib cohorts, respectively. Median OS was 17 and 11 months, respectively. Grade 3 and above events noted in ≥10% of patients included fatigue, hypertension, diarrhea, liver failure, palmar-plantar erythrodysesthesia syndrome, dyspnea, and hypophosphatemia. One death was due to hepatic failure. Serum Ang-2 dichotomized at the median was associated with improved OS in both cohorts. CONCLUSION: There was no improvement in PFS rate at 4 months in either cohort, when compared with sorafenib historical control.
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ItemDose-intense weekly cyclophosphamide, methotrexate, 5-fluorouracil, vincristine and prednisolone (CMFP) in advanced breast cancer.(Springer Science and Business Media LLC, 1990-01)Weekly chemotherapy with cyclophosphamide 80 mg m-2 day-1 p.o. continuously, methotrexate 35 mg m-2 week-1 i.v., 5-fluorouracil 500 mg m-2 week-1 i.v., vincristine 1.4 mg m-2 i.v. every two weeks and prednisolone 20 mg m-2 day-1 p.o. continuously (CMFVP) was prospectively studied in 45 previously untreated outpatients with advanced breast cancer to determine the feasibility of delivering a dose-intense regimen. Of 40 evaluable patients, complete response (CR) occurred in one patient, partial response (PR) in 20 (CR + PR 53%), stable in eight, progression in 11 and five were unevaluable for response. The median relapse-free survival for responders was 25 weeks and median survival for all patients was 31 weeks. The mean dose intensity relative to the Cooper regimen fell from 1.02 to 0.6 within the first 4 weeks of treatment and the median dose intensity achieved for all patients on study was only 0.52. Eighty-seven per cent of patients had treatment delays with a mean of 3.9 delays per patient and 71% had dose reductions. Neutropenia was the major toxicity with WHO grade 3 or 4 neutropenia (less than 1.0 x 10(9) l-1) in 62% of patients and three septic deaths while neutropenic. Dose-intense weekly CMFVP in this schedule cannot be delivered to previously untreated outpatients with advanced breast cancer.
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ItemCancer testis antigens expression in mesothelioma: role of DNA methylation and bioimmunotherapeutic implications(NATURE PUBLISHING GROUP, 2002-03-18)Recent evidences suggest that malignant mesothelioma may be sensitive to immunotherapy; however, little is known about malignant mesothelioma-associated tumour antigens. Focusing on cancer/testis antigens, the expression of well-characterised immunogenic tumour-associated antigens was investigated in malignant mesothelioma cells. At variance with MAGE-4 and NY-ESO-1, malignant mesothelioma cells frequently expressed MAGE-1, -2 and -3, GAGE 1-2, GAGE 1-6, SSX-2 and SSX 1-5, and distinct malignant mesothelioma cells concomitantly expressed at least four cancer/testis antigens. Additionally, the tumour-associated antigens RAGE-1 was expressed at high levels in both benign and malignant mesothelial cells. Lastly, treatment with the DNA hypomethylating agent 5-aza-2'-deoxycytidine induced and up-regulated the expression of the cancer/testis antigen examined in malignant mesothelioma cells. Overall, these findings strongly suggest that cancer/testis antigens-based immunotherapy may represent a suitable therapeutic approach to malignant mesothelioma, and foresee the clinical use of 5-aza-2'-deoxycytidine to design new chemo-immunotherapeutic strategies in malignant mesothelioma patients.
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ItemSomatostatin receptor expression, tumour response, and quality of life in patients with advanced hepatocellular carcinoma treated with long-acting octreotide(NATURE PUBLISHING GROUP, 2006-10-09)Octreotide may extend survival in hepatocellular carcinoma (HCC). Forty-one per cent of HCCs have high-affinity somatostatin receptors. We aimed to determine the feasibility, safety, and activity of long-acting octreotide in advanced HCC; to identify the best method for assessing somatostatin receptor expression; to relate receptor expression to clinical outcomes; and to evaluate toxicity. Sixty-three patients with advanced HCC received intramuscular long-acting octreotide 20 mg monthly until progression or toxicity. Median age was 67 years (range 28-81 years), male 81%, Child-Pugh A 83%, and B 17%. The aetiologies of chronic liver disease were alcohol (22%), viral hepatitis (44%), and haemochromatosis (6%). Prior treatments for HCC included surgery (8%), chemotherapy (2%), local ablation (11%), and chemoembolisation (6%). One patient had an objective partial tumour response (2%, 95% CI 0-9%). Serum alpha-fetoprotein levels decreased more than 50% in four (6%). Median survival was 8 months. Thirty four of 61 patients (56%) had receptor expression detected by scintigraphy; no clear relationship with clinical outcomes was identified. There were few grade 3 or 4 toxicities: hyperglycaemia (8%), hypoglycaemia (2%), diarrhoea (5%), and anorexia (2%). Patients reported improvements in some symptoms, but no major changes in quality of life were detected. Long-acting octreotide is safe in advanced HCC. We found little evidence of anticancer activity. A definitive randomised trial would identify whether patients benefit from this treatment in other ways.
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ItemA Novel HLA-B18 Restricted CD8+T Cell Epitope Is Efficiently Cross-Presented by Dendritic Cells from Soluble Tumor Antigen(PUBLIC LIBRARY SCIENCE, 2012-09-06)NY-ESO-1 has been a major target of many immunotherapy trials because it is expressed by various cancers and is highly immunogenic. In this study, we have identified a novel HLA-B*1801-restricted CD8(+) T cell epitope, NY-ESO-1(88-96) (LEFYLAMPF) and compared its direct- and cross-presentation to that of the reported NY-ESO-1(157-165) epitope restricted to HLA-A*0201. Although both epitopes were readily cross-presented by DCs exposed to various forms of full-length NY-ESO-1 antigen, remarkably NY-ESO-1(88-96) is much more efficiently cross-presented from the soluble form, than NY-ESO-1(157-165). On the other hand, NY-ESO-1(157-165) is efficiently presented by NY-ESO-1-expressing tumor cells and its presentation was not enhanced by IFN-γ treatment, which induced immunoproteasome as demonstrated by Western blots and functionally a decreased presentation of Melan A(26-35); whereas NY-ESO-1(88-96) was very inefficiently presented by the same tumor cell lines, except for one that expressed high level of immunoproteasome. It was only presented when the tumor cells were first IFN-γ treated, followed by infection with recombinant vaccinia virus encoding NY-ESO-1, which dramatically increased NY-ESO-1 expression. These data indicate that the presentation of NY-ESO-1(88-96) is immunoproteasome dependent. Furthermore, a survey was conducted on multiple samples collected from HLA-B18(+) melanoma patients. Surprisingly, all the detectable responses to NY-ESO-1(88-96) from patients, including those who received NY-ESO-1 ISCOMATRIX™ vaccine were induced spontaneously. Taken together, these results imply that some epitopes can be inefficiently presented by tumor cells although the corresponding CD8(+) T cell responses are efficiently primed in vivo by DCs cross-presenting these epitopes. The potential implications for cancer vaccine strategies are further discussed.