A Multi-Center Clinical Study to Harvest and Characterize Circulating Tumor Cells from Patients with Metastatic Breast Cancer Using the Parsortix(®) PC1 System

SIMPLE SUMMARY: There is a great need to understand the cellular and molecular characteristics of cancer when access to the tumor is limited. Circulating tumor cells (CTCs) captured from the blood of cancer patients may serve as a surrogate source of tumor material. However, the only FDA-cleared CTC assay has been limited to counting CTC in blood and and lack further characterization of the CTCs. In this study, we tested the Parsortix(®) PC1 System that captures and harvests a wide range of CTCs from peripheral blood that are amenable for further evaluation. The device was assessed in a large, multicenter clinical trial including patients with metastatic breast cancer and healthy volunteers, with enriched CTC evaluated by 4 downstream techniques commonly available in clinical laboratories. The data generated from this study was used to support FDA clearance for the Parsortix System. ABSTRACT: Circulating tumor cells (CTCs) captured from the blood of cancer patients may serve as a surrogate source of tumor material that can be obtained via a venipuncture (also known as a liquid biopsy) and used to better understand tumor characteristics. However, the only FDA-cleared CTC assay has been limited to the enumeration of surface marker–defined cells and not further characterization of the CTCs. In this study, we tested the ability of a semi-automated device capable of capturing and harvesting CTCs from peripheral blood based on cell size and deformability, agnostic of cell-surface markers (the Parsortix(®) PC1 System), to yield CTCs for evaluation by downstream techniques commonly available in clinical laboratories. The data generated from this study were used to support a De Novo request (DEN200062) for the classification of this device, which the FDA recently granted. As part of a multicenter clinical trial, peripheral blood samples from 216 patients with metastatic breast cancer (MBC) and 205 healthy volunteers were subjected to CTC enrichment. A board-certified pathologist enumerated the CTCs from each participant by cytologic evaluation of Wright-Giemsa-stained slides. As proof of principle, cells harvested from a concurrent parallel sample provided by each participant were evaluated using one of three additional evaluation techniques: molecular profiling by qRT-PCR, RNA sequencing, or cytogenetic analysis of HER2 amplification by FISH. The study demonstrated that the Parsortix(®) PC1 System can effectively capture and harvest CTCs from the peripheral blood of MBC patients and that the harvested cells can be evaluated using orthogonal methodologies such as gene expression and/or Fluorescence In Situ Hybridization (FISH).