From ASCEND-5 to ALUR to ALTA-3, an Anti-Climactic End to the Era of Randomized Phase 3 Trials of Next-Generation ALK TKIs in the Crizotinib-Refractory Setting

The competing roles of various next-generation ALK TKIs in the first and second line treatment setting of advanced ALK+ NSCLC were based on many phase 3 clinical trials in both the first-line and crizotinib-refractory settings. The approval of all next-generation ALK TKIs was first in the crizotinib-refractory setting, based on a large-scale Phase 2 trial, and was then followed by at least one global randomized phase 3 trial comparing to platinum-based chemotherapy (ASCEND-4) or to crizotinib (ALEX, ALTA-1L, eXalt3, CROWN). In addition, three randomized phase 3 trials in the crizotinib-refractory setting were also conducted by next-generation ALK TKIs that were developed earlier before the superiority of next-generation ALK TKIs was demonstrated in order to secure the approval of these ALK TKIs in the crizotinib-refractory setting. These three crizotinib-refractory randomized trials were: ASCEND-5 (ceritinib), ALUR (alectinib), and ALTA-3 (brigatinib). The outcome of the ATLA-3 trial was recently presented closing out the chapter where next-generation ALK TKIs were investigated in the crizotinib-refractory setting as they have replaced crizotinib as the standard of care first-line treatment of advanced ALK+ NSCLC. This editorial summarizes the results of next-generation ALK TKIs in randomized crizotinib-refractory trials and provides a perspective on how natural history of ALK+ NSCLC may potentially be altered with sequential treatment. ALTA-3 compared brigatinib to alectinib, showing that both achieved near identical blinded independent review committee (BIRC)-assessed progression-free survival (PFS) (19.2–19.3 months). Importantly, 4.8% of brigatinib-treated patients developed interstitial lung disease (ILD) while no alectinib-treated patients developed ILD. Dose reduction and discontinuation due to treatment-related adverse events were 21% and 5%, respectively, for brigatinib-treated patients compared to 11% and 2%, respectively, for alectinib-treated patients. Upon analysis of these findings, we speculate that brigatinib may have a diminishing role in the treatment of advanced ALK+ NSCLC.