Background: Anaplastic lymphoma kinase-positive (ALK-positive) disease occurs in approximately 5% of all patients with non-small-cell lung cancer, with a similar incidence reported in Asian patients. This study is the first phase 3 randomised trial recruiting only Asian patients to compare alectinib with crizotinib as a first-line treatment for ALK-positive non-small-cell lung cancer with 600 mg of alectinib twice per day. This study assessed consistency of the progression-free survival benefit with the global phase 3 ALEX study.
Methods: In this randomised, open-label, phase 3 study done at 21 investigational sites in China, South Korea, and Thailand, Asian patients, aged 18 years or older, with ALK-positive non-small-cell lung cancer were randomly assigned (2:1) to twice-daily oral alectinib (600 mg) or crizotinib (250 mg). Patients were randomly assigned via a block-stratified (block size three) randomisation procedure, done centrally via an interactive voice or web response system, with stratification by Eastern Cooperative Oncology Group performance status and baseline CNS metastases. Clinical staff and the funder's drug safety and medical monitoring staff had access to treatment assignments. The independent review committee was masked to treatment assignment, and funder personnel did not have access to efficacy and safety summaries by treatment group, before the formal reporting of study results. Patients with asymptomatic CNS metastases were permitted. The primary endpoint was investigator-assessed progression-free survival. The primary analysis population for efficacy was the intention-to-treat population, defined as all randomly assigned patients. The primary analysis population for safety was defined as all patients who received at least one dose of study medication. This trial is registered with ClinicalTrials.gov, number NCT02838420.
Findings: Between Aug 3, 2016, and May 16, 2017, 187 patients were randomly assigned to treatment: 125 to alectinib and 62 to crizotinib. Median follow-up was 16·2 months (IQR 13·7-17·6) in the alectinib group, and 15·0 months (12·5-17·3) in the crizotinib group. Investigator-assessed progression-free survival was significantly prolonged with alectinib versus crizotinib (hazard ratio [HR] 0·22, 95% CI 0·13-0·38; p<0·0001; median progression-free survival not estimable vs 11·1 months). Independent review committee-assessed progression-free survival was also significantly longer in the alectinib group compared with the crizotinib group (HR 0·37, 0·22-0·61; p<0·0001). The proportion of patients who achieved an objective response was 114 (91%) of 125 with alectinib, and 48 (77%) of 62 with crizotinib, with a longer duration of response for alectinib than crizotinib (HR 0·22, 95% CI 0·12-0·40; p<0·0001). Time to CNS progression (cause-specific HR 0·14) and the percentage of patients who achieved a CNS objective response with measurable or non-measurable baseline CNS lesions were improved (32 [73%] of 44 patients treated with alectinib vs five [22%] of 23 patients treated with crizotinib). Despite longer treatment duration with alectinib than crizotinib (14·7 months vs 12·6 months, respectively), fewer patients had grade 3-5 adverse events (36 [29%] of 125 vs 30 [48%] of 62, respectively) or serious adverse events (19 [15%] of 125 vs 16 [26%] of 62, respectively).
Interpretation: Our results align with ALEX, confirming the clinical benefit of 600 mg of alectinib twice per day as a first-line treatment for ALK-positive non-small-cell lung cancer.
Funding: F Hoffmann-La Roche.
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