Safety and Efficacy of 7 Days on/7 Days off Versus 14 Days on/7 Days off Schedules of Capecitabine in Patients with Metastatic Colorectal Cancer: A Retrospective Review.

INTRODUCTION/BACKGROUND: The administration schedule of capecitabine for the treatment of metastatic colorectal cancer (mCRC) in clinical trials has been 14 days of drug with 7 days off in a 21 day cycle (14/7). In an effort to improve tolerability, an alternative every other week treatment (7/7) is often administered. The purpose of this study was to determine the safety and efficacy of administering 7/7 compared with 14/7 capecitabine dosing.

MATERIALS AND METHODS

In this retrospective study, mCRC patients received capecitabine on a 7/7 or 14/7 schedule. The primary objective was to determine the tolerability of the respective dosing schedules, defined according to frequency of dose reductions and treatment delays. Secondary objectives included comparisons of objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and safety of dosing strategies.

RESULTS

Of 175 included patients, 73 (41.7%) received the capecitabine 7/7 schedule and 102 (58.3%) received the 14/7 schedule. There was a statistically significant difference between the 7/7 and 14/7 groups with regard to dose reductions (4% vs. 29%; P < .001) and treatment delays (22% vs. 43%; P = .004). The incidence of any adverse effects (45% vs. 72%; P < .001) and specifically, palmar-plantar erythrodysesthesia (18% vs. 45%; P < .001), were significantly higher in the 14/7 group. No significant difference was seen with regard to ORR, PFS, or OS.

CONCLUSION

Patients with mCRC who received the 7/7 schedule had significantly fewer dose reductions and treatment delays compared with patients who received the 14/7 schedule. Although no difference in efficacy outcomes were observed, prospective studies are needed to confirm these findings.