In this study, 48 patients with advanced non-small cell lung cancer (NSCLC), who had been shown to have a common epidermal growth factor receptor EGFR mutation at an initial biopsy, and had developed tyrosine kinase inhibitor (TKI) resistance, were tested using Inivita’s InVisionTM ctDNA liquid biopsy platform for the presence of T790 mutations. The T790 mutation is a known mechanism of acquired resistance to the first and second TKIs used in the treatment of this patient cohort. Importantly, the patients in the study were not able to have a new tissue biopsy at the time of disease progression for reasons including lack of available tissue or the localisation of the tumour. The ctDNA T790M mutational status was detected in 50% of NSCLC patients, which is consistent with detection rates seen in tissue biopsies.
Benjamin Besse, Chairman of the Thoracic Unit, Medical Oncologist at Gustave Roussy said: “This Inivata test allowed us to rescue patients unable to undergo a biopsy. The latter situation is frequent in EGFR-mutated NSCLC patients. Indeed, recurrences during first line TKIs may be too small or in a site inadequate for molecular testing, such as bone metastases. Liquid biopsies are easy to manage in a real-life setting, and can be performed potentially in any centre. They are meant to become the upfront test, keeping tissue biopsy as a second line test. I foresee a future where liquid biopsy will not only be used as a diagnostic tool, but also as a dynamic test to prospectively monitor NSCLC evolution.”
The T790M positive NSCLC patients within the study were treated with osimertinib (marketed as TAGRISSO™), a third generation TKI recently approved by both the US Food and Drug Administration (FDA) and European Medicines Agency (EMA) for patients with acquired EGFR T790M mutations. Among evaluable patients, osimertinib gave a partial response rate of 62.5% and a stable disease rate of 37.5%. All responses were confirmed responses. These results are comparable to the efficacy reported with osimertinib in patients with the T790M mutation detected in tumour tissue biopsy as seen in registration trials.
These results show, in a prospective clinical setting, that ctDNA from liquid biopsy can be used as a surrogate marker for T790M in tumour tissue and, more broadly, the potential for the technology to guide personalised cancer treatment.
Clive Morris, Chief Medical Officer at Inivata, said: “This study shows for the first time the clinical utility of our InVisionTM ctDNA liquid biopsy platform in guiding treatment decisions and delivering better patient outcomes. While a relatively small study, the fact that these patients were able to receive targeted therapy despite the unavailability of a tissue biopsy and the close comparability of mutation detection and treatment outcomes to standard practice based on tissue profiling is extremely encouraging. We are proud to have worked closely with Gustave Roussy, a world-renowned cancer centre, on this study. We have an extensive, international clinical validation programme ongoing and look forward to presenting further results as we advance towards commercialisation of our InVisionTM platform.”
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