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Blood-Based Diagnostic Assay Measures Immunotherapy Biomarker PD-L1


Blood-Based Diagnostic Assay Measures Immunotherapy Biomarker PD-L1
ddPCR Assay Measures mRNA Expressions from Immune and Cancer Cell; Key Step In Development of Immunotherapy Test

New data from Biodesix® evaluating an assay in development demonstrated the potential to measure circulating PD-L1 through mRNA in blood through multiplexed droplet digital™ PCR (ddPCR, Bio-Rad, Inc.) detection. The assay uses proprietary RNA isolation methods consistent with Biodesix’s commercialized GeneStrat® ALK, ROS1, and RET variant tests. Existing immunohistochemistry (IHC) PD-L1 tissue tests are used to identify patients who may benefit from cancer immunotherapies. The data were presented last week at the ASCO-SITC Clinical Immuno-Oncology Program in Orlando, Florida.


“Understanding PD-L1 status is a central question in immuno-oncology, and obtaining a reliable result will provide vital insight for patients and their physicians,” said Dr. Michael Pritchett, Director of the Chest Center of the Carolinas at FirstHealth Moore Regional Hospital in Pinehurst, North Carolina “Combining PD-L1 results with the existing blood-based offering that includes driver mutations provides a rapid, non-invasive testing option to inform treatment decisions.”


PD-L1 has been detected in up to 50% of all human cancers and has become a major focus of therapeutic and biomarker research.[1] Patients whose tumors over-express the PD-L1 protein are more likely to respond to certain immuno-oncology therapeutics, and several PD-L1-related therapies have received FDA approval. These checkpoint inhibitors are widely anticipated to provide the backbone for rapidly evolving approaches to immune-oncology. With IHC tests, higher levels of PD-L1 protein have been correlated with higher likelihood of response for a number of tumor types.


The assay was described in the study, “Development of ddPCR blood-based diagnostic tests that simultaneously measure mRNA expression from immune and cancer cells”. The GeneStrat test offers accurate, non-invasive blood-based mutation results with a 72-hour turnaround time for patients with non-small cell lung cancer, delivering rapid information for diagnosis or therapy monitoring to identify specific driver mutations with proven clinical utility.


Biodesix is currently exploring opportunities to validate this assay and establish its clinical utility, including potential correlation with IHC results. 



About Biodesix

Biodesix® is a molecular diagnostics company advancing the development of innovative, multi-omic blood tests in oncology to enable precision medicine. Biodesix discovers, develops and commercializes multivariate protein and genomic liquid biopsy tests, including the GeneStrat® and VeriStrat® tests, that deliver results within 72 hours. The company is changing the standard of care by providing physicians with diagnostic tests and with the Biodesix Lung Reflex™ testing strategy, for better therapeutic guidance, more accurate prognosis and enhanced disease monitoring to improve patient outcomes. At the forefront of personalized medicine, Biodesix is developing new tests to identify patients who may benefit from immunotherapies. In addition to developing novel diagnostics independently, the company partners with biotechnology and pharmaceutical companies to develop companion diagnostics for use with therapeutic agents.



[1] Chen et al. Clin Cancer Res. 2012


Topics: ASCO-SITC, cancer immunotherapy, Press Releases, immmunotherapy test, PD-L1