Report: VeriStrat Serum Test Predicts Response But Not Survival Benefit From Erlotinib
Authors say further study needed to define test’s clinical utility (Oct. 15)
The International Association for the Study of Lung Cancer (IASLC) has reported that the VeriStrat plasma test, marketed by Biodesix, can predict response but not survival benefit from erlotinib (Tarceva, Genentech). The study, published in the November 2012 issue of the Journal of Thoracic Oncology, was conducted in a subset of patients enrolled in a phase III trial of erlotinib versus placebo in previously treated patients with advanced non–small-cell lung cancer (NSCLC).
VeriStrat is a commercially available serum- or plasma-based test using matrix-assisted laser desorption ionization mass-spectrometry methods. In the new study, plasma samples were obtained from 441 enrolled patients. VeriStrat testing was successful in 98.9% of the samples (436), classifying patients as “good” or “poor.” For “good” patients, the median survival period was 10.5 months on erlotinib versus 6.6 months on placebo. For “poor” patients, the median survival period was 4 month for patients on erlotinib and 3.1 months for patients on placebo.
In addition to confirming that the VeriStrat test was predictive for response, the authors looked at whether the test was predictive for a differential survival benefit versus placebo. The interaction term comparing relative benefit in the two treatment cohorts was not significant (P = 0.48), indicating that both the “good” and “poor” cohorts derived similar relative benefits from erlotinib. VeriStart was prognostic for both progression-free and overall survival in patients who did not receive erlotinib.
The authors concluded that the VeriStrat test is able to predict a response to erlotinib but neither progression nor overall survival, and that the test is a prognostic biomarker in previously treated patients with advanced NSCLC. The authors also noted that further studies are needed to define the clinical utility of VeriStrat and other blood-based biomarkers in defining the appropriate patient population for therapy with erlotinib and other epidermal growth factor receptor (EGFR)-based therapies.
Source: IASLC, October 15, 2012.