When Caris Life Sciences' new cancer blood test goes fishing for mutations, it casts a wide net—wide enough to capture as many as 22,000 of them, the company says.
The company has only presented early validation data on the Assure liquid biopsy assay, which made its debut at the annual meeting of the American Society of Clinical Oncology. But Caris says it scans for as many as 22,000 genes—using a combination of whole-exome and whole-transcriptome sequencing that sifts through the pieces of DNA and RNA found floating in the bloodstream.
While current cancer blood tests focus on smaller panels of genes to help characterize patients and their tumors, Caris’ approach aims to “leave no stone unturned in properly guiding treatment selection and ongoing cancer care management,” CEO David Halbert said in a statement.
The Assure blood test, based on the company’s similarly broad tissue-based biopsy, is also designed to determine a patient’s microsatellite instability status, their loss of heterozygosity as well as the total number of mutations driving the tumor—measures that can help gauge a patient's cancer risks and steer therapy plans.
In addition, the assay can identify specific types of genetic alterations that are found in blood-making stem cells, known as clonal hematopoiesis of indeterminate potential, or CHIP, which can prelude future hematologic cancers.
Beyond its use in diagnosis and profiling, Caris hopes Assure will also help enable repeated, minimally invasive screening of cancer patients undergoing treatment to help physicians keep watch for emerging mutations that could lead to tumors becoming resistant to therapy.
By searching broadly for genetic material that may be marred by malformed tumor cells, an initial study of the test’s performance showed a false-positive rate of less than 0.01%, due in part to the analysis of CHIP mutations, according to the company, which said it plans to release additional validation data in the coming months.
Caris plans to begin making the Assure test commercially available under limited release in the third quarter of this year, before expanding availability through early 2023.