The effect of EML4-ALK break-apart ratio on crizotinib outcomes in non-small cell lung cancer harboring EML4-ALK rearrangement.

A total of 70 patients were enrolled in the study. The most significant decrease in the risk of the progression or death was detected at the 50% threshold value and it was accepted as the optimal threshold. The median PFS was 17.9 vs. 7.06 months (mo) in the pts with high ALK rearrangement than low (HR: 0.43, 95% CI 0.24-0.76, p 0.004). The median OS was also significant longer in high ALK rearrange group (44.6 mo vs. 16.8 mo; HR: 0.37, 95% Cl 0.1883-0.7315; p 0.004). The intracranial progression during crizotinib treatment was significantly frequent in the pts with high ALK rearrangement (62.5-32.5%, P 0.039) DISCUSSION: In this study, we found that the high break-apart ratio can predict the extent of benefit from targeted therapy in ALK-positive NSCLC patients. Based on the results of this study, the percentage of the ALK rearrangement can be used to predict treatment outcome and to choose the optimal targeted agent in the treatment of metastatic ALK-positive NSCLC.