GFR mutation detection in ctDNA from NSCLC patient plasma : A ross-platform comparison of leading technologies to support the linical development of AZD 9291 enneth

Objectives: To assess the ability of different technology platforms to detect epidermal growth factor receptor (EGFR) mutations, including T790M, from circulating tumor DNA (ctDNA) in advanced non-small cell lung cancer (NSCLC) patients. Materials and methods: A comparison of multiple platforms for detecting EGFR mutations in plasma ctDNA was undertaken. Plasma samples were collected from patients entering the ongoing AURA trial (NCT01802632), investigating the safety, tolerability, and efficacy of AZD9291 in patients with EGFRsensitizing mutation-positive NSCLC. Plasma was collected prior to AZD9291 dosing but following clinical progression on a previous EGFR-tyrosine kinase inhibitor (TKI). Extracted ctDNA was analyzed using two non-digital platforms (cobas® EGFR Mutation Test and therascreenTM EGFR amplification refractory mutation system assay) and two digital platforms (Droplet DigitalTM PCR and BEAMing digital PCR [dPCR]). Results: Preliminary assessment (38 samples) was conducted using all four platforms. For EGFR-TKIsensitizing mutations, high sensitivity (78–100%) and specificity (93–100%) were observed using tissue as a non-reference standard. For the T790M mutation, the digital platforms outperformed the non-digital platforms. Subsequent assessment using 72 additional baseline plasma samples was conducted using the cobas® EGFR Mutation Test and BEAMing dPCR. The two platforms demonstrated high sensitivity (82–87%) and specificity (97%) for EGFR-sensitizing mutations. For the T790M mutation, the sensitivity and specificity were 73% and 67%, respectively, with the cobas® EGFR Mutation Test, and 81% and 58%, respectively, with BEAMing dPCR. Concordance between the platforms was >90%, showing that multiple platforms are capable of sensitive and specific detection of EGFR-TKI-sensitizing mutations from NSCLC patient plasma. Conclusion: The cobas® EGFR Mutation Test and BEAMing dPCR demonstrate a high sensitivity for T790M mutation detection. Genomic heterogeneity of T790M-mediated resistance may explain the reduced specificity observed with plasm the use of both platforms in th © 2015 The Authors. Pu Abbreviations: ARMS, amplification refractory mutation system; BEAM, beads, emulsio NA; dPCR, digital polymerase chain reaction; ddPCR, Droplet Digital PCR; EGFR, epiderm xtra-thoracic metastatic disease; NSCLC, non-small cell lung cancer; PCR, polymerase ch ∗ Corresponding author. E-mail address: kenneth.thress@astrazeneca.com (K.S. Thress). ttp://dx.doi. org/10.1016/j.lungcan. 2015.10. 004 169-5002/© 2015 The Authors. Published by Elsevier Ireland Ltd. T http://creativecommons.org/licenses/by-nc-nd/4.0/). a-based detection of T790M mutations versus tissue. These data support e AZD9291 clinical development program. blished by Elsevier Ireland Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). ns, amplification, and magnetics; CR, complete response; ctDNA, circulating tumor al growth factor receptor; M1a/M0, disease confined to the thoracic cavity; M1b, ain reaction; PR, partial response; SD, stable disease; TKI, tyrosine kinase inhibitor. his is an open access article under the CC BY-NC-ND license