For a study, researchers used data from the phase III ALEX study in treatment-naive, advanced ALK plus non–small cell lung cancer to assess the prognostic value of circulating cell-free DNA (cfDNA) (NSCLC). Patients were randomly assigned either alectinib 600 mg twice daily (n=152) or crizotinib 250 mg twice daily (n=151). cfDNA was measured in baseline plasma samples, and patients were divided into less than equal to median and more than median cfDNA biomarker-evaluable groups (BEP). The effect of cfDNA concentration on outcomes was studied using a Cox regression model with the treatment group as a covariate and multivariate analyses. In the BEP, the median cfDNA concentration was 11.53 ng/mL (n = 276). There was a positive correlation between cfDNA concentration and the number of lesions, organ lesion sites, and tumor size (sum of longest diameter; all P<0.0001). Patients in the more than median BEP were more likely to experience disease progression than those in the less than equal to median BEP in both treatment arms [alectinib adjusted HR=2.04; 95% CI, 1.07–3.89; P=0.0305 and crizotinib adjusted HR=1.83; 95% CI, 1.11–3.00, P=0.0169].In both the less than equal to median and more than median BEPs, alectinib had a longer median progression-free survival than crizotinib (P<0.0001). Overall survival data are still preliminary; survival probability was lower in both treatment arms in the more than median versus less than equal to median BEP (alectinib HR=2.52; 95% CI, 1.08–5.88; P=0.0333 and crizotinib HR=2.63; 95% CI, 1.27–5.47; P=0.0096). According to these findings, plasma cfDNA concentration may have prognostic value in advanced ALK+ NSCLC. Prospective studies were needed to investigate this finding.
Source:aacrjournals.org/clincancerres/article/28/9/1800/694467/Circulating-Cell-free-DNA-as-a-Prognostic
