Early evolution of BRAFV600status in the blood of melanoma patients correlates with clinical outcome and identifies patients refractory to therapy

Supplemental Digital Content is available in the text.Serial analysis of BRAFmutations in circulating-free DNA (cfDNA) could be of prognostic value in melanoma patients. We collected blood samples from 63 advanced BRAFV600E/Kmelanoma patients and determined BRAFV600E/Kstatus in cfDNA using a quantitative 5′-nuclease PCR-based assay. Levels of BRAFmutation in pre-cfDNAs were associated significantly with tumour burden, progression-free survival and overall survival. Changes in BRAFstatus in cfDNA after initiation of treatment (early-cfDNA) had a significant correlation with outcome. In patients with persistent BRAFmutations (n=12), progression-free survival and overall survival were 3.5 months [95% confidence interval (CI): 1.6–4.6] and 5.3 months (95% CI: 3.4–8.1) compared with 16.6 months (95% CI: 8.2–22.3) and 21.9 months (95% CI: 10.2–NR) in patients with BRAFnegativization (n=16), and 15.1 months (95% CI: 2.3–NR) and NR (95% CI: 5.1–NR) in patients who maintained their initial negative status (n=12) (P<0.0001). The median duration of response in patients with radiological response, but persistence of BRAFV600in early-cfDNA (n=5) was 4 months. Our study indicates that serial BRAFtesting in the blood of advanced melanoma identifies patients refractory to therapy.