Correlation of Src activation with response to dasatinib, capecitabine, oxaliplatin, and bevacizumab in advanced solid tumors.

11036 Background: Src inhibition may augment sensitivity to chemotherapy, but in unselected patients (pts) with advanced solid tumors, src inhibitors have shown limited clinical activity. Biomarkers to predict benefit from src inhibitors in advanced solid tumors are not yet known. Methods: 22 pts (dose escalation cohort= 12 pts; colorectal cancer [CRC] expansion cohort= 10 pts) were enrolled in a phase I study to determine the safety and tolerability of the src inhibitor dasatinib with capecitabine, oxaliplatin, and bevacizumab (J Clin Oncol 29: 2011 [suppl; abstr 3586]). Src activation (src-a) was assessed in tumors from 16 evaluable pts. Src-a was measured by immunohistochemistry (IHC) in formalin-fixed, paraffin-embedded tumor samples using an antibody that selectively recognizes the active conformation of src (clone 28). A GI pathologist who was blinded to pt outcomes graded membranous src-a using a standard semi-quantitative method. The endpoint of this exploratory analysis was objective response rat...