Potential Predictive Biomarker of Response to Crizotinib for Lung Cancer
Serial molecular analysis of circulating tumor cells (CTCs) may identify a predictive biomarker for crizotinib efficacy in patients with ALK-rearranged non–small cell lung cancer (NSCLC), according to a recent study by Pailler et al in Cancer Research. Although confirmatory studies are still needed, the investigators consider this “liquid biopsy” approach a possible alternative to tumor biopsy for real-time patient monitoring and clinical outcome prediction in this patient population.
Conducted at Gustave Roussy in Villejuif, France, this study included 39 patients with stage IV ALK-rearranged NSCLC between 2011 and 2014 who received crizotinib twice daily at the initiation of therapy. CTCs were classified into different subsets based on the presence of ALK-rearrangement and/or ALK-copy number gain (ALK-CNG) signals.
The investigators found a significant association between the decrease in CTC number with ALK-CNG on crizotinib and a longer progression-free survival (likelihood ratio test, P=.025). According to a multivariate analysis, the dynamic change of CTC with ALK-CNG was the strongest factor associated with progression-free survival (hazard ratio = 4.485; 95% confidence interval: 1.543–13.030, P=.006).
