ANGLE plc announced the publication of results from a multi-centre clinical study undertaken with The University of Texas MD Anderson Cancer Center, TX, Wilmot Cancer Institute, University of Rochester, NY, Robert H Lurie Comprehensive Cancer Center, Northwestern University, IL, and Norris Comprehensive Cancer Center, University of Southern California, CA, US. The Parsortix® system was used to enrich circulating tumour cells (CTCs) from 207 patients with metastatic breast cancer (MBC) with each patient providing two blood tubes allowing for testing of multiple downstream analytical techniques. This research highlights the ability to perform multiple downstream analyses on CTCs enriched using the Parsortix system.

CTCs isolated from the peripheral blood of MBC patients were successfully evaluated by cytology (i.e., Wright-Giemsa staining), real time quantitative reverse transcriptome PCR (qRT-PCR), RNA sequencing and fluorescence in situ hybridisation (FISH). The analyses, demonstrated to be successfully performed on CTCs enriched by the Parsortix system, use commercially available reagents and are standard techniques used in many clinical and/or laboratory settings. This successful study provided data to support the De Novo Class II Classification application for the Parsortix system for use in harvesting cancer cells from MBC patient blood for subsequent, user-validated analysis, which was granted by US Food and Drug Administration (FDA) on May 24th 2022.

Further details about the study: The cells captured by the Parsortix system from one of the blood tubes were subjected to Wright-Giemsa staining and a board-certified pathologist enumerated the CTCs by cytologic evaluation. The second blood tube for each patient was used to assess the proof of principle for one of three additional evaluation techniques: gene expression analysis by qRT-PCR, RNA sequencing, or analysis of HER2 amplification by FISH. The cytologic evaluation identified CTCs in 48.5% of all evaluable MBC patient samples independent of tumour subtype.

CTCs were identified in 33.3% of newly diagnosed MBC patients, and in 56.8% of recurring or progressing MBC patients. Of the MBC patients' samples assessed by qRT-PCR, 52.7% were positive for at least one of the CTC-related genes and showed a general correlation with CTC count particularly at higher burden. There were 200 differentially expressed genes in the MBC patients, compared to healthy donors, as shown through RNA sequencing, with significant enrichment of cancer signalling pathway genes.

HER2 amplification, detected via FISH analysis, was observed in a single patient sample with identifiable CTCs that also had HER2 positive tissue status.