Merck expands portfolio of liquid biopsy tests

According to Mechelen-based Biocartis, the PCR assay, which detects 21 mutations in the KRAS gene, was co-developed within a partnership with Merck dating back to January 2016. Biocartis liquid biopsy test currently is for research use only. However, Biocartis expects CE-marked IVD versions to be launched in the second half of 2017. The assay allows fully automated KRAS mutation testing operating directly on 1 ml of blood plasma in approximately two hours turnaround time.

Liquid biopsy assays are complementing the highly invasive testing on tissue biopsies, the current gold standard. According to Biocartis, liquid biopsy is offering "an attractive approach when limited or no tissue is available". The vision of diagnostics companies, such as Qiagen, Sysmex Inostics, Roche, Abbott etc, however, is to monitor therapy response in the future. "We are excited about the potential of this and future liquid biopsy assays, where research has shown in the past years that circulating tumour DNA can be used for disease monitoring in patients undergoing treatment," confirmed Erwin Sablon, Biocartis’ Head of R&D and Alliance Management. The company's partnership with Merck comprises the development of a second liquid biopsy test addressing NRAS and BRAF mutations that are common in mCRC and allow selection of potential responders to targeted therapies. 

The Idylla assay, however, is not the first KRAS/NRAS test Merck has in its portfolio of blood-based companion diagnstics tests. In February 2015, Merck launched testing with a CE-marked OncoBEAM RAS CRC IVD assay, an all-RAS panel co-developed with Sysmex Inostics, that distinguishes 34 NRAS/KRAS mutations and allows selection of patients with RAS wildtyp tumours who respond well to Merck's EGFR blocker Erbitux (Cetuximab). Research-only KRAS tests from Bio-Rad or Illumina compete with Biocartis’ new assay.