Clinical utility of a blood-based BRAF V600E mutation assay in melanoma
Menée à partir d'échantillons sanguins prélevés sur 128 patients atteints d'un mélanome, cette étude évalue la sensibilité et la spécificité d'une technique permettant d'identifier la présence de la mutation V600E du gène BRAF au cours d'un traitement par inhibiteur de BRAF
BRAF inhibitors (BRAFi) have led to clinical benefit in patients with melanoma. The development of a blood-based assay to detect and quantify BRAF levels in these patients has diagnostic, prognostic, and predictive capabilities that could guide treatment decisions. Blood BRAFV600E detection and quantification was performed on samples from 128 patients with Stage II (19), III (67), and IV (42) melanoma. Tissue BRAF analysis was performed in all patients with Stage IV disease and in selected patients with Stage II and III disease. Clinical outcomes were correlated to initial BRAF levels as well as BRAF level dynamics. Serial analysis was performed on 17 Stage IV melanoma patients treated with BRAFi and compared to tumor measurements by RECIST. The assay was highly sensitive (96%) and specific (95%) in the Stage IV setting, using a blood level of 4.8 pg as "positive". BRAF levels typically decreased following BRAFi. A subset of these patients (5) had an increase in BRAF V600E values 42-112 days prior to clinical or radiographic disease progression (PD). From 86 patients with resected, stage II or III melanoma, 39 had evidence of disease relapse (45.3 %). Furthermore, BRAF mutation in the blood after surgical resection in these patients was not associated with a difference in relapse risk, though tissue BRAF status was only available for a subset of patients. In summary we have developed a highly sensitive and specific, blood-based assay to detect BRAFV600 mutation in patients with melanoma.
Molecular Cancer Therapeutics , résumé, 2014