Dr. Lang on the Potential Applications for the Parsortix® PC1 System in Breast Cancer

Julie Lang, MD, chief of Breast Surgery, co-leader of the Breast Cancer Program, General Surgery, the Cleveland Clinic Main Campus, discusses potential applications for the Parsortix® PC1 system in metastatic breast cancer.

The Parsortix PC1 system is an in vitro diagnostic device intended to enrich circulating tumor cells (CTCs) from peripheral blood from patients with metastatic breast cancer. In May 2022, the FDA granted class II clearance for Parsortix as a diagnostic for metastatic breast cancer, making it the first device approved for the use of detecting cancer by harvesting cells from a patient blood sample.

The approval was based on findings from a prospective clinical trial (NCT03427450) conducted at The University of Texas MD Anderson Cancer Center, the University of Southern California, the Northwestern Medical Center, and the University of Rochester, which evaluated blood samples taken from patients with breast cancer and healthy female volunteers with no history of cancer. Findings presented at the 2022 San Antonio Breast Cancer Symposium showed that harvested cells can be evaluated using standard orthogonal methodologies, such as gene expression and fluorescence in situ hybridization, to identify and characterize CTCs.

Although investigators were excited about the trial’s findings and the FDA approval, additional studies could include better cytology methods so that a higher proportion of CTCs adhere to the cytology slides used in the device, Lang notes. Based on cell line proof-of-principle studies done in parallel to the clinical trial, 37% to 51% of the CTCs were harvested by Parsortix, meaning the test could have increased sensitivity with more refined cytology methods, Lang says.

Lang explains that sequencing studies to detect mutations could also be performed, and other studies could include single-cell sequencing to examine tumor biology and better understand resistance in metastatic breast cancer cells.

Individual hospitals will need to decide how to apply Parsortix and what subsequent studies may be beneficial in their patient populations, Lang concludes.