Phase-II study of dose attenuated schedule of irinotecan, capecitabine, and celecoxib in advanced colorectal cancer.

Background: The cyclooxygenase-2 (COX-2) enzyme plays a major role in tumor progression and resistance to chemotherapy. A Phase-II study was undertaken to determine the activity of a dose attenuated schedule of irinotecan, capecitabine, and the COX-2 inhibitor celecoxib in patients with advanced colorectal cancer.

Methods: The eligibility criteria included a pathologically or cytologically confirmed diagnosis of adenocarcinoma of the colon or rectum that was metastatic. 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 celecoxib at a daily dose of 800 mg continuously. Cycles were repeated every 21 days.

Results: Fifty-one patients were enrolled (median age 58 years; M : F 31 : 20). The objective response rate was 21/51 = 41% [95% confidence intervals (CI), 0.28-0.55]. The median time to progression was 7.7 months (95% CI, 6.2-8.6 months). Median survival time and probability of survival at 1 year were 21.2 months (95% CI, 13.8-n/a), and 75% (95% CI, 0.63-0.88), respectively. The major toxicity was Grade 3 or 4 diarrhea, seen in 24 and 10% of patients, respectively. There were no treatment related deaths.

Conclusions: The lower dose intensity of irinotecan appeared to maintain activity and improve tolerability when combined with capecitabine. The addition of celecoxib to irinotecan and capecitabine did not appear to significantly increase the activity of this doublet based on the RECIST criteria for objective response.