Laura Mezquita, Hospital Clinic Barcelona, Barcelona, Spain, shares the findings of the ARIA study: an assessment of the activity of next-generation ALK tyrosine kinase inhibitors (TKIs) based of the presence of ALK resistance mutations (ALKm) in ctDNA. ALK-positive advanced non-small cell lung cancer (NSCLC) patients with prior ALK-TKI therapy were identified and a liquid biopsy was conducted prior to brigatinib or lorlatinib treatment. ALKm were detected in 28% of the population, where G1202R was the most common. Lorlatinib was shown to have more activity in ALKm patients compared with brigatinib, with superior response rates and progression free survival. The findings suggest ctDNA could act as a biomarker to guide sequential treatment choices but larger trials are needed. This interview took place during the IASLC World Conference on Lung Cancer (WCLC) virtual meeting 2021.