BRAF mutation analysis in circulating free tumor DNA of melanoma patients treated with BRAF inhibitors.

BRAFV600E is a unique molecular marker for metastatic melanoma, being the most frequent somatic point mutation in this malignancy. Detection of BRAFV600E in blood could have prognostic and predictive value and could be useful for monitoring response to BRAF-targeted therapy. We developed a rapid, sensitive method for the detection and quantification of BRAFV600E in circulating free DNA (cfDNA) isolated from plasma and serum on the basis of a quantitative 5'-nuclease PCR (Taqman) in the presence of a peptide-nucleic acid. We validated the assay in 92 lung, colon, and melanoma archival serum and plasma samples with paired tumor tissue (40 wild-type and 52 BRAFV600E). The correlation of cfDNA BRAFV600E with clinical parameters was further explored in 22 metastatic melanoma patients treated with BRAF inhibitors. Our assay could detect and quantify BRAFV600E in mixed samples with as little as 0.005% mutant DNA (copy number ratio 1 : 20 000), with a specificity of 100% and a sensitivity of 57.7% in archival serum and plasma samples. In 22 melanoma patients treated with BRAF inhibitors, the median progression-free survival was 3.6 months for those showing BRAFV600E in pretreatment cfDNA compared with 13.4 months for those in whom the mutation was not detected (P=0.021). Moreover, the median overall survival for positive versus negative BRAFV600E tests in pretreatment cfDNA differed significantly (7 vs. 21.8 months, P=0.017). This finding indicates that the sensitive detection and accurate quantification of low-abundance BRAFV600E alleles in cfDNA using our assay can be useful for predicting treatment outcome.

Reduced folate carrier (RFC) as a predictive marker for response to pemetrexed in advanced non-small cell lung cancer (NSCLC).

INTRODUCTION: RFC is the major transport system in mammalian cells for folate cofactors and antifolate therapeutics. The aim of this study was to assess the predictive value of RFC expression in patients receiving pemetrexed for advanced NSCLC. METHODS: The study was carried out in a population of 48 patients with advanced NSCLC which have received pemetrexed monotherapy in second and third line. RFC expression was assessed using a two-step model of immunohistochemical staining in paraffin-embedded tissue samples. RESULTS: RFC expression was detected in 16 (33 %) patients. In the global population, the median progression free survival (PFS) and the median overall survival (OS) were 3.3 and 6.5 months respectively. The subgroup of patients with expression of RFC had a tendency to better median PFS (4.5 vs 2.8 months; p = 0.926) and median OS (11.7 vs 4.8; p = 0.150). In patients with adenocarcinoma histology and RFC expression median OS after treatment with pemetrexed was 14.4 months versus 5.0 in those with adenocarcinoma but without RFC expression (p = 0.039). CONCLUSIONS: These results suggest the possible relation between RFC expression and response to treatment with antifolates (pemetrexed) independently of the tumor histology. Further studies are required to confirm these results.

Prolonged clinical benefit of everolimus therapy in the management of high-grade pancreatic neuroendocrine carcinoma.

Treatment options for patients with high-grade pancreatic neuroendocrine tumors (pNET) are limited, especially for those with progressive disease and for those who experience treatment failure. Everolimus, an oral inhibitor of mammalian target of rapamycin (mTOR), has been approved for the treatment of patients with low- or intermediate-grade advanced pNET. In the randomized phase III RADIANT-3 study in patients with low- or intermediate-grade advanced pNET, everolimus significantly increased progression-free survival (PFS) and decreased the relative risk for disease progression by 65% over placebo. This case report describes a heavily pretreated patient with high-grade pNET and liver and peritoneal metastases who achieved prolonged PFS, clinically relevant partial radiologic tumor response, and resolution of constitutional symptoms with improvement in Karnofsky performance status while receiving a combination of everolimus and octreotide long-acting repeatable (LAR). Radiologic and clinical responses were maintained for 19 months, with minimal toxicity over the course of treatment. This case supports the findings that the combination of everolimus plus octreotide LAR may be considered for use in patients with high-grade pNET and progressive disease. Although behavior and aggressiveness are different between low- or intermediate-grade and high-grade pNET, some high-grade pNET may express mTOR; hence, everolimus should be considered in a clinical trial.