Biocept—a provider of molecular diagnostic assays, products and services—presented a study demonstrating the ability of its CNSide assay to identify HER2 and other actionable tumor alterations in the cerebrospinal fluid of patients with breast cancer and leptomeningeal disease (LMD).

The poster was chosen for a spotlight presentation at the San Antonio Breast Cancer Symposium.

LMD is a complication in which cancer spreads to the membrane surrounding the brain and spinal cord. The current standard of care for diagnosing LMD is through clinical evaluation, imaging and cytology, which have limited sensitivity and are unable to identify important tumor biomarkers such as HER2. HER2-targeted treatment for patients with breast cancer and LMD may provide substantial survival advantages over the expected median survival of less than three months.

“Our CNSide assay can be used both to confirm the presence of tumors and to identify important biomarkers in LMD such as HER2,” says Michael Dugan, MD, chief medical officer and medical director of Biocept. “Finding HER2 amplification in breast cancer tumor cells in the CSF is critical because anti-HER2 targeted therapy provides one of the best options for physicians treating patients with breast cancer who have developed the life-threatening complications of LMD.”

In this analysis, cerebrospinal fluid (CSF) of 63 patients with stage IV breast cancer and LMD was collected, and CSF tumor cells were captured and characterized using CNSide. HER2 amplification was detected in 56% of all patients. HER2 status differed between the primary tumor and LMD in 38% of cases, with more than 80% of those patients exhibiting a switch from a HER2-negative primary tumor to HER2-positive LMD.

“Knowing if a patient’s tumor is HER2 positive or negative, and especially whether HER2 status has changed from primary tumor to LMD, allows us to more precisely treat those patients and achieve a better response,” says Amir Azadi, MD., a neuro-oncologist at Banner MD Anderson, who earlier this year discussed the advantages of CNSide in detecting central nervous system metastases. “Patients with brain metastases and leptomeningeal disease have a very poor prognosis. CNSide provides new information to help guide treatment decisions that may extend life expectancy and improve quality of life for these patients.”

The CNSide CSF assay is designed to help physicians better detect and manage treatment of metastatic cancers involving the central nervous system. It provides a timely and accurate method to help diagnose these tumors, identify actionable biomarkers and assess response to therapy, with the goal of improving patient survival and quality of life.

The assay is based on Biocept’s proprietary quantitative tumor cell capture and detection method, paired with assays to identify actionable molecular treatment targets. CNSide has the ability to answer key questions that may help inform treatment decisions: Is there involvement by tumor? Is there a target for treatment? Is there a trend with respect to treatment response?

The poster, titled, “Characterization of HER2 Amplification in the Cerebrospinal Fluid of Patients with Leptomeningeal Disease in Stage IV Patients with Breast Cancer,” can be accessed here.