Upfront ultrafast multigene panel testing for NCCN guideline–recommended biomarker detection in advanced NSCLC.

e15094 Background: NCCN Guidelines for advanced non–small cell lung cancer (NSCLC) recommend comprehensive biomarker assessment using multigene panel testing (MGPT) prior to initiating systemic therapy. Although rapid testing with subsequent MGPT is acknowledged in the guidelines, the optimal testing strategy remains undefined. Sequential single-gene testing (SGT) is associated with prolonged turnaround times (TAT), increased tissue consumption, and a higher risk of incomplete biomarker evaluation. Ultrafast next-generation sequencing (NGS)–based MGPT assays have emerged as potential upfront alternatives; however, the Centers for Medicare & Medicaid Services National Coverage Determination restricting reimbursement to a single NGS assay emphasizes the importance of initial test selection. Methods: Concordance between an ultrafast targeted MGPT (uMGPT; 50 genes) and a large MGPT (lMGPT; 523 genes) was evaluated for NCCN-recommended biomarkers with OncoKB Level 1 evidence. Archival clinical specimens from patients with advanced NSCLC (n = 104), previously analyzed by lMGPT, were retested using uMGPT. Concordance was assessed using positive and negative percent agreement. Laboratory TAT was defined as the time from specimen receipt to NGS result reporting following pathology review and nucleic acid extraction. Results: 37 NCCN-recommended biomarkers were identified across 104 samples. The uMGPT demonstrated complete concordance with lMGPT for the biomarkers tested, including 100% positive percent agreement for EGFR mutations (n = 14), KRAS G12C (n = 24), ALK fusions (n = 2), and MET exon 14 skipping alterations (n = 2), with 100% negative percent agreement. Median laboratory TAT for uMGPT was 1 day. Conclusions: uMGPT enabled rapid and comprehensive detection of the NCCN-recommended biomarkers evaluated in this study for advanced NSCLC while conserving limited tissue. Compared with sequential SGT, uMGPT enables simultaneous identification of multiple actionable alterations, reducing the risk of incomplete biomarker assessment. Although uMGPT does not encompass the full range of biomarkers assessed by lMGPT, it may function as a complementary rapid, upfront approach alongside lMGPT to identify therapeutically relevant alterations in NSCLC. Consideration of assay performance, operational feasibility, and clinical timelines may help guide optimal rapid biomarker testing strategies and support the integration of uMGPT into routine clinical workflows.