Analytical Validation and Clinical Sensitivity of the Belay Summit™ 2.0 Cerebrospinal Fluid Liquid Biopsy Test-An...

The latest National Comprehensive Cancer Network (NCCN) Central Nervous System (CNS) Guidelines recommend utilizing next-generation sequencing (NGS) to enable comprehensive genomic profiling (CGP) as the preferred approach for molecular characterization of central nervous system (CNS) malignancies. CNS malignancies present distinct challenges due to the infeasibility of tissue-based testing for many patients and the restrictive nature of the blood-brain barrier (BBB) making plasma-based liquid biopsy an ineffective alternative. Recent advances in liquid biopsy have extended molecular testing beyond plasma to include cerebrospinal fluid (CSF), which serves as a valuable source for tumor-derived nucleic acids.

The Belay Summit™ 2.0 is a high-throughput CGP assay capable of detecting multiple variant types, including single nucleotide variants (SNVs) and small insertion and deletions (Indels), copy number variations (CNVs), gene fusions, splice variants, and immunotherapy biomarkers such as microsatellite instability (MSI) and tumor mutational burden (TMB). This study details the analytical and clinical validation of Summit™ 2.0 to assess its technical performance and clinical sensitivity. Analytical validation was conducted using 68 specimens, demonstrating robust and reproducible detection of all variant types with 15 ng of CSF-derived total nucleic acid (tNA).

The analytical sensitivity of the Belay Summit™ 2.0 assay for SNVs and Indels was determined to be 96.7% with a 100% limit of detection (LoD) at a variant allele frequency of 0.3%. Clinical validity was evaluated across a cohort of 118 CSF specimens, including both primary and metastatic CNS tumors, demonstrating 96% sensitivity and 98% specificity.

These findings support the use of the Belay Summit™ 2.0 assay for accurate and reproducible genomic profiling of CNS tumors using tumor-derived nucleic acids from CSF in patients for whom tissue-based testing is considered infeasible, unsafe, or not deemed by the prescribing physician to be clinically appropriate.