Rapid Assay Identifies Genetic Mutations Associated with NSCLC

A rapid blood-based diagnostic assay is now available to identify genetic mutations associated with non-small-cell lung cancer (NSCLC), which is the first step in establishing personalized treatment for the patient.

Nearly 80% of cancer patients do not have genetic mutation results available at initial oncology consultation; up to 25% of patients begin treatment before receiving their results. Lack of this information hinders the ability to pursue optimal treatment strategies.

To repair this lack, a new assay system that determines circulating tumor DNA mutations and RNA variants in whole blood has been developed by the biotechnology firm Biodesix, Inc. The test is specific for NSCLC where certain genetic mutations can be used to identify patients who might be sensitive or resistant to a particular cancer therapy. For example, epidermal growth factor (EGFR) mutations may result in sensitivity to drugs that are EGFR tyrosine kinase inhibitors (TKIs), such as erlotinib or gefitinib, whereas individuals with the EGFR T790M mutation are more resistant to these drugs. Patients with ALK rearrangements do not respond to EGFR-TKIs, but are sensitive to other targeted therapies (such as ceretinib).

During the development phase, the assay was used to test samples from 219 donors with cancer and from 30 normal control subjects. Of the more than 1,600 samples tested, 10.5% had EGFR sensitizing, 18.8% EGFR resistance, 13.2% KRAS, and 2% EML4-ALK (anaplastic lymphoma kinase) mutations. The test demonstrated high sensitivity (greater than 80%) and specificity (100%) for detecting each type of mutation. Mutation results were available within 72 hours for 94% of the tests, and in most cases, blood tests and tissue biopsies yielded the same results.

"This study is critical because it is the first to demonstrate the uptake of blood-based testing for actionable mutations in the non-hospital (community) setting. Physicians and patients in a community setting may not have easy access to a large hospital or other diagnosis/treatment facility. This assay provides results within 72 hours from sample receipt," said senior author Dr. Gary A. Pestano, vice president of development and operations at Biodesix, Inc. "The described assay can detect actionable mutations in patients diagnosed with earlier stages of NSCLC, thereby improving clinical outcomes."

The study was published in the May 2017 issue of The Journal of Molecular Diagnostics.