(ChemotherapyAdvisor) – The VeriStrat proteomic blood test predicts erlotinib response but not erlotinib-associated survival benefits among patients with non-small cell lung cancer (NSCLC), according to a study in the Journal of Thoracic Oncology.

“VeriStrat is able to predict response to erlotinib and is a prognostic biomarker in previously treated patients with advanced NSCLC,” reported David P. Carbone, MD, PhD, of the Department of Medicine at Vanderbilt-Ingram Cancer Center in Nashville, Tennessee, and coauthors. “Veristrat was predictive for objective response (P=0.002) but was not able to predict for differential survival benefit from erlotinib (P=0.48).”

The authors studied 436 pretreatment plasma samples from the phase 3, placebo-controlled BR.21 erlotinib trial, using the VeriStrat test, which yields “good” or “poor” prognosis findings.

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“Of 252 erlotinib-treated patients evaluable for response, 157 (62%) were calssified as Good and 95 (38%) as Poor,” Dr. Carbone’s team reported. “Good patients had a significantly higher response rate than Poor patients did (11.5% versus 1.1%, P=0.02), with a Good classification remaining independently significantly correlated with response after adjustment for potential confounding factors.”

For patients with VeriStrat Good results, the median survival time was 10.5 months on erlotibib versus 6.6 months for placebo (HR 0.63, 95% CI, 0.47-0.85;P=0.002); for patients with VeriStrat Poor results, median survival was 4 months among patients administered erlotinib versus 3.1 months among placebo-arm patients (HR 0.77, 95% CI, 0.55-1.06, P=0.11, n.s.).

EGFR copy number was modestly predictive of erlotinib’s OS benefit (P=0.05), the authors reported.

“Further studies are required to define the clinical utility of VeriStrat and other blood-based biomarkers in defining the appropriate patient population for therapy with erlotinib and other EGFR-based therapeutics,” the authors noted.