Decline in serum soluble E-cadherin and low baseline matrix metalloproteinase-9 are associated with response to combination celecoxib and erlotinib therapy in advanced non-small cell lung cancer
7640 Background: Cyclooxygenase-2 (COX-2) overexpression may mediate resistance to EGFR TK inhibition through prostaglandin E2 (PGE2)-dependent promotion of epithelial to mesenchymal transition (EMT). Thomson, et al. reported that the suppression of epithelial markers such as E-cadherin led to resistance to erlotinib (Cancer Res 2005;65:9455). In addition, PGE2 downregulates E-cadherin expression by upregulating transcriptional repressors including ZEB1 and Snail, as described by Dohadwala et al (Cancer Res 2006;66:5338). These findings suggest that COX-2 inhibition may enhance the efficacy of EGFR TKI therapy in NSCLC. Methods: A phase I, dose escalation trial to was performed investigating the combination of celecoxib and erlotinib in pts with advanced NSCLC. Soluble E-cadherin (sEC) was evaluated by ELISA in pt serum at baseline and weeks 4 and 8 of treatment. Other markers of COX-2 gene expression were evaluated by ELISA, including matrix metalloproteinase (MMP)-9, MMP-2 and tissue inhibitor of MMP (TIMP1). Results: 22 pts were enrolled and 21 were evaluable for the determination of the optimal dose, toxicity assessment and response (reported in Clin Cancer Res 2006;12:3381). Here we report serum sEC and MMP-9 levels, which were analyzed according to best response (PR, SD or PD) in 21 pts. SEC was analyzed according to best response (PR, SD or PD). We found a significant decrease in sEC between baseline and week 8 in pts with PR when compared to those with SD or PD (p = 0.021). In pts who responded to the combination therapy, baseline MMP-9 was significantly lower compared to non-responders (p = 0.006). Conclusions: SEC, MMP-9 and other downstream markers of COX-2 gene expression may be useful for assessing response to combination celecoxib and erlotinib in pts with advanced NSCLC. A randomized Phase II trial is planned comparing erlotinib and celecoxib with erlotinib plus placebo in advanced NSCLC, to evaluate the efficacy of this combination therapy and to assess these and other biomarkers in both serum and tumor tissue. Supported by ASCO Young Investigator Award, UCLA Lung Cancer SPORE NCI P50 CA 90388 and GLAVAHS Career Development Award. No significant financial relationships to disclose.