Treatment duration as a surrogate endpoint to evaluate the efficacy of crizotinib in sequential therapy for patients with advanced ALK‐positive non‐small cell lung cancer: A retrospective, real‐world study

OBJECTIVES: Crizotinib has demonstrated good efficacy in patients with anaplastic lymphoma kinase (ALK)‐positive non‐small cell lung cancer (NSCLC). Continuing crizotinib therapy beyond progressive disease (CBPD) can achieve ongoing survival benefit in real‐world clinical practice. In terms of survival, progression‐free survival (PFS), the most commonly used endpoint in efficacy evaluations, may not provide accurate information on the impact of this intervention when crizotinib is administered in sequential therapy. MATERIALS AND METHODS: A single‐center, retrospective study of 201 ALK‐positive advanced NSCLC patients was conducted to analyze the PFS, overall survival (OS), and treatment duration (TD) of crizotinib. The correlations between the TD of crizotinib and OS in CBPD and non‐CBPD groups of patients were compared. RESULTS: All patients were treated with crizotinib, 150 of whom eventually developed progressive disease (PD). The median PFS1 and PFS2 were 13.2 months and 10.5 months, respectively. The OS of the whole population was 50.5 months. The median TD was 20.7 months, which is shorter than direct PFS1 + PFS2. The TD of crizotinib in CBPD group was significantly longer than that in non‐CBPD group (median 39.7 vs 15.0 months, P < .001). TD correlated better with OS (R = .79) than PFS (R = .64) in the CBPD group. CONCLUSIONS: Crizotinib showed good efficacy in patients with ALK‐positive advanced NSCLC. Instead of PFS, treatment duration might be a more reasonable surrogate clinical endpoint in patients who received crizotinib in sequential therapy.