EGFR ELISA Kit

The WJOG8815L phase II clinical study involves patients with non-small cell lung cancer (NSCLC) that harbored the EGFR T790M mutation, which confers resistance to EGFR tyrosine kinase inhibitors (TKIs). The purpose of this study was to assess the predictive value of monitoring EGFR genomic alterations in circulating tumor DNA (ctDNA) from patients with NSCLC that undergo treatment with the third-generation EGFR-TKI osimertinib. Plasma samples of 52 patients harboring the EGFR T790M mutation were obtained pretreatment (Pre), on day 1 of treatment cycle 4 (C4) or cycle 9 (C9), and at diagnosis of disease progression or treatment discontinuation (PD/stop). CtDNA was screened for EGFR-TKI-sensitizing mutations, the EGFR T790M mutation, and other genomic alterations using the cobas EGFR Mutation Test v2 (cobas), droplet digital PCR (ddPCR), and targeted deep sequencing. Analysis of the sensitizing-and T790M-EGFR mutant fractions (MFs) was used to determine tumor mutational burden. Both MFs were found to decrease during treatment, whereas rebound of the sensitizing EGFR MF was observed at PD/stop, suggesting that osimertinib targeted both T790M mutation-positive tumors and tumors with sensitizing EGFR mutations. Significant differences in the response rates and progression-free survival were observed between the sensitizing EGFR MF-high and sensitizing EGFR MF-low groups (cutoff: median) at C4. In conclusion, ctDNA monitoring for sensitizing EGFR mutations at C4 is suitable for predicting the treatment outcomes in NSCLC patients receiving osimertinib (Clinical Trial Registration No.: UMIN000022076).

Background There are few studies that directly compare the effects of osimertinib on patients with non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) T790M mutation between the generation of prior EGFR tyrosine kinase inhibitors (TKIs). Methods We retrospectively reviewed clinical data from the medical records of consecutive patients with advanced NSCLC who had developed resistance to first- or second-generation EGFR-TKIs due to EGFR T790M mutation and were subsequently treated with osimertinib at Juntendo University Hospital. In patients with available tumor samples, target amplicon sequencing analyses were performed to explore the genetic biomarkers. Results A total of 38 patients with NSCLC harboring EGFR T790M mutation were treated with osimertinib. Eight patients were classified into group A (afatinib followed by osimertinib) and 30 patients were classified into group B (first-generation EGFR-TKI followed by osimertinib). Progression-free survival (PFS) was significantly longer in group A than in group B (median PFS; not reached vs. 11.0 months, P = 0.018). Fourteen patients had available tissue samples collected before osimertinib treatment for target sequencing. In group A we found no additional mutations, other than EGFR T790M mutation. On the other hand, there were three samples in which other mutations emerged, in addition to EGFR T790M mutation, in group B. Conclusions PFS of osimertinib was significantly longer in patients with NSCLC harboring EGFR T790M mutation after treatment with afatinib than in patients after treatment with first generation EGFR-TKIs. Additional mutations other than EGFR T790M may affect the efficacy of osimertinib treatment. Key points Significant findings of the study: PFS of osimertinib was significantly longer in patients with NSCLC harboring EGFR T790M mutation after treatment with afatinib than in patients after treatment with first generation EGFR-TKIs. What this study adds: Additional mutations other than EGFR T790M may affect the efficacy of osimertinib treatment.