VeriStrat®, a serum based proteomic assay can help physicians identify patients who are likely to have good or poor outcomes after treatment with EGFR inhibitors and thereby can provide valuable insight into whether chemotherapy or targeted therapy with TARCEVA®, a EGFR-TKI, is appropriate for their patients with advanced NSCLC, in the second line setting. This information is especially important for patients without an EGFR mutation or for those, whose EGFR mutation status is unknown. In the PROSE trial, patients classified as VeriStrat-Poor have better survival with chemotherapy than TARCEVA®, whereas patients classified as VeriStrat-Good have similar survival with TARCEVA® and chemotherapy. This data was presented at the 2013 ASCO meeting.