System Detects Circulating Tumor Cells in Blood

The results of serial testing for CTCs with the CellSearch System, in conjunction with other clinical methods for monitoring, can help physicians assess disease progression, thereby guiding earlier, more informed care decisions.

Detection and enumeration of CTCs, cancer cells that detach from solid tumors and enter the blood stream, is automated by the CellSearch system, the standard in a new class of diagnostic tools. The system's specificity, sensitivity, and reproducibility allow for serial assessment of CTCs as early as the first cycle of treatment to help evaluate disease progression.

The test uses antibodies that are joined to microscopic iron particles, called ferrofluid. These antibody/ferrofluid combinations attach specifically to CTCs. Powerful magnets then "pull” the CTCs out of the blood sample. They are stained with additional bio-molecules and chemicals so that they can be positively identified as CTCs. The CellSearch test differs from the current standard of care because it can be used much earlier than traditional imaging (e.g., computed tomography [CT] scans), and is not subject to the variation observed with other blood tests, called serum tumor markers.

A prospective, multi-center clinical trial was conducted to validate the expanded clearance for CellSearch. The study, which took place in 55 clinical centers in the United States and Europe, involved 430 metastatic colorectal patients about to enter first- or second-line therapy. Data showed that patients with less than three CTCs at baseline had significantly better survival rates versus patients with more than three CTCs--an overall finding consistent with metastatic breast cancer patients. Data also showed that CTCs are a strong independent predictor of progression-free survival and overall survival, and that the combination of CTC analysis and radiologic assessment may provide the most accurate assessment of prognosis.

Veridex, LLC (Warren, NJ, USA) announced that the U.S. Food and Drug Administration (FDA; Rockville, MD, USA) has granted an expanded clearance for its CellSearch system to be used as an aid in the monitoring of metastatic colorectal cancer. CellSearch is currently approved for monitoring metastatic breast cancer.

Veridex, LLC, a Johnson & Johnson company, develops cancer diagnostic products that enable earlier disease detection as well as more accurate staging, monitoring, and therapeutic selection. The company is initially developing two complementary product lines: CellSearch assays that identify, enumerate, and characterize circulating tumor cells directly from whole blood; and GeneSearch assays that use molecular technology to diagnose, stage, and more accurately characterize tumors.


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U.S. Food and Drug Administration