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Plus Therapeutics subsidiary CNSide Diagnostics has reported data from the multi-centre FORESEE trial, which highlights the CNSide cerebrospinal fluid (CSF) Assay Platform's role in enhancing the diagnosis and treatment of leptomeningeal metastasis (LM) in breast cancer and non-small cell lung cancer (NSCLC) patients.
In a prospective clinical trial, FORESEE enrolled subjects with breast or NSCLC who had suspected or confirmed LM.
The study aimed to address the limitations of standard diagnostic methods such as clinical evaluation, MRI, and cytology, which often lack sensitivity and specificity, posing challenges for physicians in managing LM and determining optimal treatment strategies.
The CNSide CSF Assay Platform comprises four laboratory-developed tests (LDTs) for diagnosis, selection of treatment, and subject monitoring with LM from carcinomas or melanoma.
It employs cellular assays, including immunocytochemistry (ICC) and fluorescence in situ hybridisation (FISH), as well as molecular assays such as next-generation sequencing (NGS), to detect and enumerate tumour cells and recognise biomarkers.
The trial's primary endpoint was met, with the platform influencing treatment decisions in more than 90% of cases, far exceeding the 20% target.
The platform's sensitivity in detecting tumour cells stood at 80%, compared to 29% for CSF cytology.
Additionally, CNSide detected actionable mutations such as the amplification of human epidermal growth factor receptor 2 (HER2), which affected therapeutic selections in 24% of cases.
The platform also exhibited high specificity and no tumour cells were detected in subjects without LM. It demonstrated an improved Negative Predictive Value for ruling out LM.
Notably, 60% of breast cancer patients with HER2-negative primary tumours showed HER2 positivity in LM tumours, guiding physician treatment strategies.
The CNSid Assay Platform enables quantitative analysis and molecular characterisation of tumour cells in cerebrospinal fluid, thereby informing and improving patient management with LM.
Plus Therapeutics CEO and president Marc Hedrick said: “Current gold standard CSF cytology lacks the sensitivity needed to reliably diagnose LM in most clinical situations and lacks utility for disease monitoring.
“The FORESEE trial shows that CNSide may be a useful tool in accurately identifying all patients with LM, ruling out patients at risk, and enhancing the disease management and monitoring of LM.”
In September 2023, Biocept announced a licensing agreement with Plus Therapeutics for the CNSide laboratory test.