RT Journal Article SR Electronic T1 Association Between COX-2 Expression and Effectiveness of COX-2 Inhibitors in a Phase II Trial in Patients with Metastatic Colorectal Adenocarcinoma JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 3559 OP 3563 VO 32 IS 8 A1 KHALDOUN ALMHANNA A1 BASSEL EL-RAYES A1 SEEMA SETHI A1 GREGORY DYSON A1 LANCE HEILBRUN A1 PHILIP A PHILIP A1 FAZLUL SARKAR YR 2012 UL http://ar.iiarjournals.org/content/32/8/3559.abstract AB Aim: The role for the cyclooxygenase-2 (COX-2) pathway in colorectal carcinogenesis has been suggested in pre-clinical models. In a previously reported phase II trial, the addition of COX-2 inhibitor celecoxib to irinotecan and capecitabine did not appear to significantly increase the activity of chemotherapy in patients with metastatic colorectal carcinoma (mCRC). We evaluated the COX-2 expression in the available tumors from enrolled patients by immunohistochemistry, as well as its correlation with clinical outcome. Patients and Methods: Fifty-one patients with mCRC were enrolled in the phase II study between June 2002 and November 2005. Patients received a combination of irinotecan 70 mg/m2 over 30 min i.v. on days 1 and 8, capecitabine 1,000 mg/m2 twice per day orally on days 1-14 and the COX-2 inhibitor celecoxib at a daily dose of 800 mg continuously. Cycles were repeated every 21 days. Formalin-fixed paraffin-embedded tumor tissue samples were available for 17 patients enrolled on this study. COX-2 expression was evaluated by immunohistochemistry and was correlated with clinical outcome. Results: In the phase II study, the objective response rate was 41%. The median time to progression was 7.7 months and median survival time was 21.2 months. Tumor COX-2 expression, by immunohistochemistry, was assessed for 17 patients enrolled in the same phase II study. While not statistically significant, the response rate was better for patients in the low COX-2 expression group, while time to progression and overall survival was longer in patients in the high COX-2 expression group. This discrepancy can be partially attributed to the small sample size. Conclusion: In the previously published phase II study, the addition of celecoxib to irinotecan and capecitabine did not appear to significantly increase the activity of chemotherapy. COX-2 expression by immunohistochemistry was neither prognostic nor predictive for response.