Efficacy of Lorlatinib in Treatment-Naive Patients With ALK-Positive Advanced NSCLC in Relation to EML4::ALK Variant Type and ALK With or Without TP53 Mutations.

INTRODUCTION: Lorlatinib, a third-generation ALK tyrosine kinase inhibitor, improved outcomes compared with crizotinib in patients with previously untreated ALK-positive advanced NSCLC in the phase 3 CROWN study. Here, we investigated response correlates using plasma circulating tumor DNA (ctDNA) and tumor tissue profiling. METHODS: ALK fusions and ALK with or without TP53 mutations were assessed by next-generation sequencing. End points included objective response rate (ORR), duration of response, and progression-free survival (PFS) by blinded independent central review on the basis of EML4::ALK variants and ALK with or without TP53 or other mutation status. RESULTS: ALK fusions were detected in the ctDNA of 62 patients in the lorlatinib arm and 64 patients in the crizotinib arm. ORRs were numerically higher with lorlatinib versus crizotinib for EML4::ALK variant 1 (v1; 80.0% versus 50.0%) and variant 2 (v2; 85.7% versus 50.0%) but were similar between the arms for variant 3 (v3; 72.2% versus 73.9%). Median PFS in the lorlatinib arm was not reached for EML4::ALK v1 and v2 and was 33.3 months for v3; in the crizotinib arm, median PFS was 7.4 months, not reached, and 5.5 months, respectively. ORRs and PFS were improved with lorlatinib versus crizotinib regardless of TP53 mutation status and in patients harboring preexisting bypass pathway resistance alterations. In the lorlatinib arm, PFS was lower in patients who had a co-occurring TP53 mutation. Results from ctDNA analysis were similar to those observed with tumor tissue samples. CONCLUSIONS: Patients with untreated ALK-positive advanced NSCLC derived greater clinical benefits, with higher ORRs and potentially longer PFS, when treated with lorlatinib compared with crizotinib, independent of EML4::ALK variant or ALK mutations, TP53 mutations, or bypass resistance alterations.

Early Circulating Tumor DNA Dynamics and Efficacy of Lorlatinib in Patients With Treatment-Naive, Advanced, ALK-Positive NSCLC.

INTRODUCTION: Circulating tumor DNA (ctDNA) has been used as a biomarker for prognostication and response to treatment. Here, we evaluate ctDNA as a potential biomarker for response to lorlatinib, a third-generation ALK tyrosine kinase inhibitor in patients with treatment-naive, advanced, ALK-positive NSCLC in the ongoing phase 3 CROWN study (NCT03052608). METHODS: Molecular responses were calculated using mean variant allele frequency (VAF), longitudinal mean change in VAF (dVAF), and ratio to baseline. Efficacy assessments (progression-free survival [PFS] and objective response rate) were paired with individual patient ctDNA and analyzed for association. RESULTS: Compared with baseline, mean VAF at week 4 was decreased in both treatment arms. Considering all detected somatic variants, a reduction in dVAF (≤0) was associated with a longer PFS in the lorlatinib arm. The hazard ratio (HR) for a dVAF less than or equal to 0 versus more than 0 was 0.50 (95% confidence interval [CI]: 0.23-1.12) in the lorlatinib arm. A similar association was not observed for crizotinib (HR = 1.00, 95% CI: 0.49-2.03). Comparing molecular responders with nonresponders, patients treated with lorlatinib who had a molecular response had longer PFS (HR = 0.37, 95% CI: 0.16-0.85); patients treated with crizotinib who had a molecular response had similar PFS as those without a molecular response (HR = 1.48, 95% CI: 0.67-3.30). CONCLUSIONS: In patients with treatment-naive, advanced, ALK-positive NSCLC, early ctDNA dynamics predicted better outcome with lorlatinib but not with crizotinib. These results suggest that ctDNA may be used to monitor and potentially predict efficacy of lorlatinib treatment.