Core Insights - Plus Therapeutics, Inc. announced positive data from a retrospective analysis of the CNSide CSF Assay Platform, which can quantify leptomeningeal metastases (LM) and monitor changes in targetable mutations over time [1][2] - The CNSide CSF Assay may catalyze the initiation of LM treatment and enable personalized cancer therapy by allowing real-time adaptation of treatment based on tumor biology [1][3] Company Overview - Plus Therapeutics is a clinical-stage pharmaceutical company focused on developing targeted radiotherapeutics for central nervous system cancers, with a pipeline that includes programs for leptomeningeal metastases and recurrent glioblastoma [6][7] - CNSide Diagnostics, LLC, a subsidiary of Plus Therapeutics, develops proprietary laboratory tests designed to identify tumor cells that have metastasized to the central nervous system [4] Research Findings - The analysis involved 613 CNSide assays ordered for 218 patients, with a significant majority (74%) being female and the most common cancers analyzed being breast (n=105) and lung (n=65) [2] - The CNSide CSF Assay demonstrated a diagnostic sensitivity 2.8 times greater than standard CSF cytology, influencing clinical management decisions in over 90% of LM cases [3][6] - The study found that 67% (412/613) of patients had detectable CSF tumor cells, with notable findings in patients undergoing multiple CSF draws [6] Clinical Implications - The CNSide CSF Assay can detect gene amplification in CSF tumor cells, providing therapeutic insights for targeting LM tumors [3] - Longitudinal analysis using CNSide may offer insights for modifying treatment strategies over time [3] Market Context - Leptomeningeal metastases occur in approximately 5% of patients with metastatic cancer, but postmortem studies suggest the frequency may be as high as 20%, indicating a need for more sensitive diagnostic options [5]