In a prespecified interim analysis, overall survival
was shown to be similar in the crizotinib
and chemotherapy groups. This analysis was immature,
and it is likely that it was confounded by
the high crossover rate among patients in the
chemotherapy group. Crossover has similarly
complicated the analysis of overall survival in
other randomized, phase 3 studies of EGFR kinase
inhibitors in patients with advanced EGFRmutant
non–small-cell lung cancer.26-28 Despite
these limitations, the median overall survival
among patients in this study from the time that
second-line therapy was initiated was remarkably
high, at longer than 20 months, suggesting that
the addition of crizotinib either before or after
second-line chemotherapy may contribute to improving
survival. In contrast, in a small retrospective
study, the median overall survival from
the time of initiation of second-line therapy among
patients with ALK-positive non–small-cell lung cancer
who had not received crizotinib was 6 months.29