A subanalysis of the phase III ALEX study has shown that alectinib (Alecensa) is more effective than the standard of care, crizotinib, in Asian patients with anaplastic lymphoma kinase (ALK)-positive non–small cell lung cancer (NSCLC), researchers reported at the European Society for Medical Oncology (ESMO) Asia 2017 Congress (Abstract 410O_PR).
The J-ALEX study demonstrated that alectinib at 300 mg twice daily improved progression-free survival compared to crizotinib in Japanese patients with ALK-positive NSCLC. The ALEX study subsequently showed improvement in progression-free survival with alectinib at 600 mg twice daily compared to crizotinib in a global population of ALK-positive NSCLC patients.
This subanalysis of the ALEX study investigated the efficacy and safety of alectinib at 600 mg twice daily compared to crizotinib in Asian vs non-Asian patients with ALK-positive NSCLC. As previously reported, the ALEX study included 303 patients who were randomized in a 1:1 ratio to receive alectinib or standard-of-care crizotinib. There were 69 Asian patients in each treatment group. The primary endpoint was progression-free survival.
A distinguishing feature of the study was that all patients underwent magnetic resonance imaging (MRI) of the brain every 6 months, regardless of whether they had brain metastases at the start of the study. The time to progression in the brain was measured and compared between the two treatment groups.
“Around 50% of NSCLC patients with ALK mutations will develop brain metastases, so it is very important to demonstrate the efficacy of alectinib in the brain,” said lead author Tony S.K. Mok, MD, FASCO, Chairman, Department of Clinical Oncology, The Chinese University of Hong Kong.
The subanalysis showed similar efficacy and safety with alectinib in Asian and non-Asian patients. Progression-free survival was longer with alectinib compared to crizotinib in Asian and non-Asian populations, with hazard ratios of 0.46 and 0.49, respectively. Alectinib reduced central nervous system (CNS) progression compared to crizotinib in the Asian and non-Asian groups, with cause-specific hazard ratios of 0.21 and 0.16, respectively. Median overall survival was not reached in either subgroup.
Response rates to alectinib and crizotinib were 81.2% vs 76.8%, respectively, for the Asian subgroup, and 84.3% vs 74.4%, respectively, for the non-Asian subgroup. The rates of nausea, vomiting, and grade III toxicities overall were lower with alectinib compared to crizotinib and similar between the Asian and non-Asian subgroups. Liver toxicity due to alectinib was slightly higher in the Asian compared to the non-Asian subgroup.
Dr. Mok said, “Alectinib, 600 mg twice daily, was similarly effective in Asian and non-Asian patients in the ALEX study in terms of progression-free survival, CNS progression, and response rate. The rates of toxicities were also comparable. The findings suggest that 600 mg should be the standard dose of alectinib across Asia.”
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