Comparison of response and survival of first-line crizotinib therapy according to EML-4 ALK fusion variants in advanced non-small cell lung cancer patients: A Turkish Oncology Group study

Abstract

Purpose: In the literature there are conflicting data about the treatment efficacy of anaplastic lymphoma kinase (ALK) translocation positive non-small cell lung cancer (NSCLC) patients according to ALK fusion variants. We aimed to study the impact of ALK fusion variants on the survival of first-line crizotinib-treated NSCLC patients. Methods: 101 locally advanced or metastatic ALK positive NSCLC patients treated with first-line crizotinib between January 2013 and December 2019 were retrospectively evaluated. We studied ALK fusion variants in 38 of those patients with adequate tumor tissue with reverse transcription polymerase chain reaction (RT PCR). Patients having ALK fusion variant 1 (v1) and non-variant 1 (non-v1) were compared for survival and response to crizotinib. Results: Median age was 52.5 years (range 35-74), and 22 of 38 patients were male (57.9%). EML-4 ALK v1 was seen in 26 patients (68.4%) and 12 were non-v1 (variant 3a/b in 6, and non-EML-4 ALK variants in 6 patients). Objective response rate was 60.5% in all patients, whereas it was 61.5% in v1 and 58.3% in non-v1 group. Median progression-free survival (PFS) and overall survival (OS) were similar. Median PFS was 13.1 months in v1, and 12.4 months in non-v1 (p=0.232). Median OS was 23.2 months in v1, and 19.4 months non-v1 (p=0.493). Conclusion: ALK v1 and non-v1 patients had the same OS and PFS after first-line crizotinib treatment, however there was a trend for v1 group for better OS.