Dr. Ramalingam on Plasma EGFR Mutations as a Predictor of Response in NSCLC

Suresh S. Ramalingam, MD, deputy director, Winship Cancer Institute of Emory University, discusses plasma EGFR mutations as a predictor of response to osimertinib (Tagrisso) in the AURA3 trial in non—small cell lung cancer (NSCLC).

AURA3 is a randomized, international, open-label trial evaluating osimertinib in patients with T790M-positive advanced NSCLC who progressed after first-line EGFR-TKI therapy. In the study, patients were randomized to receive either osimertinib or systemic chemotherapy. Findings published in the New England Journal of Medicine showed a superior progression-free survival for patients treated with osimertinib compared with chemotherapy.

Suresh says that investigators were interested in studying the peripheral blood of these patients to see how osimertinib works. Plasma cell samples were gathered from patients at serial time points as they participated in the AURA3 trial. These patients underwent a baseline blood collection, a blood collection at 3 weeks, and a last collection at 6 weeks. Investigators looked for the presence of the original EGFR mutation—exon19 or exon21—and the T790M mutation in the blood. The outcome tended to be better in patients who do not have detectable circulating tumor DNA in the blood.