Impact of EML4-ALK Variants and Co-Occurring TP53 Mutations on Duration of First-Line ALK Tyrosine Kinase Inhibitor Treatment and Overall Survival in ALK Fusion-Positive NSCLC: Real-World Outcomes From the GuardantINFORM database.

INTRODUCTION: Tyrosine kinase inhibitors (TKIs) are first-line treatment options for ALK-positive (ALK+) NSCLC. Factors such as variant allele frequencies (VAFs), EML4-ALK fusion variant, and concurrent TP53 mutations (TP53mt) in circulating tumor DNA (ctDNA) may affect treatment outcomes. We evaluated their effects on time to discontinuation (TTD) of first-line treatment with next-generation ALK TKIs in a real-world setting. METHODS: Adults with advanced or metastatic NSCLC and ctDNA-detected ALK fusion who received first-line next-generation ALK TKI monotherapy were identified in GuardantINFORM. Effects of ALK fusion VAF, EML4-ALK variants, and TP53mt detection on TTD were evaluated. RESULTS: A total of 307 patients with ALK fusion in baseline ctDNA received first-line alectinib (n = 280), brigatinib (n = 15), lorlatinib (n = 9), or ceritinib (n = 3); 150 patients (49%) had ALK-fusion VAF greater than or equal to 1%. Among 232 patients with EML4-ALK fusions (v1, 50%; v3, 36%), TP53mt co-occurred with v1 in 42 (18%) and v3 in 32 (14%). Patients with VAF less than 1% versus greater than or equal to 1% had a median TTD of 32.2 (95% confidence interval [CI]: 20.7-not estimable [NE]) versus 14.7 months (10.4-19.9; hazard ratio [HR] = 1.57 [95% CI: 1.09-2.26]; p = 0.0146). Median TTD was 13.1 (9.5-19.9) versus 27.6 months (17.3-NE) in patients with versus without TP53mt detected (HR = 1.53 [1.07-2.19]; p = 0.0202) and 20.3 (14.4-NE) versus 11.5 months (7.4-31.1) in patients with v1 versus v3 (HR = 1.29 [0.83-2.01]; p = 0.2641). Patients with TP53mt and v3 had a median TTD of 7.4 months (95% CI: 4.2-31.1). CONCLUSION: High ctDNA VAF, EML4-ALK v3, and TP53mt were associated with early discontinuation of first-line ALK TKIs.

Real-World Treatment Patterns and Outcomes Across Three Lines of Therapy in Patients with ALK+ NSCLC.

INTRODUCTION: Anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) are standard first- and second-line treatment for advanced ALK+ non-small cell lung cancer (NSCLC). We evaluated outcomes in patients with ALK+ NSCLC receiving third-line ALK TKI versus non-ALK-directed therapy. METHODS: Flatiron Health OncoEMR data were extracted for patients with ALK+ NSCLC initiating first-line ALK TKI between January 2015 and March 2022 followed by second-line ALK TKI and third-line ALK TKI (group A) or non-TKI therapy (group B). Time-to-treatment discontinuation (TTD) and overall survival (OS) were analyzed using multivariate modelling. RESULTS: Among patients receiving third-line ALK TKI (A, n = 85) or non-TKI therapy (B, n = 43), most received first-line crizotinib (A/B: 64%/60%) and second-line alectinib (36%/30%), ceritinib (24%/19%), or lorlatinib (15%/30%). Common third-line treatments were lorlatinib/alectinib (41%/33%) in A and immunotherapy, chemotherapy, or chemotherapy + immunotherapy (30%/28%/21%) in B. Group A versus B had longer TTD of first-line treatment (hazard ratio [HR] 0.62, 95% confidence interval [CI] 0.41-0.93; p = 0.020) and second-line treatment (HR 0.50, 95% CI 0.33-0.75; p < 0.001) and longer OS from start of first-line treatment (HR 0.32, 95% CI 0.19-0.54; p < 0.001) and second-line treatment (HR 0.40, 95% CI 0.24-0.66; p < 0.001). For third-line treatment, median TTD (A/B) was 6.2/2.4 months (HR 0.61, 95% CI 0.37-1.00; p = 0.049) and OS was 17.6/6.5 months (HR 0.57, 95% CI 0.33-0.98; p = 0.042). CONCLUSIONS: Patients receiving third-line non-ALK-directed therapy had suboptimal outcomes on prior TKIs. Patients with longer duration of prior ALK TKI treatment appeared to benefit from third-line ALK TKIs.