Randomized phase III study of capecitabine plus oxaliplatin compared with fluorouracil/folinic acid plus oxaliplatin as first-line therapy for metastatic colorectal cancer.

Purpose: To evaluate whether capecitabine plus oxaliplatin (XELOX) is noninferior to fluorouracil. folinic acid, and oxaliplatin (FOLFOX-4) as first-line therapy in metastatic colorectal cancer (MCRC).

Patients And Methods: The initial design of this trial was a randomized, two-arm, noninferiority, phase III comparison of XELOX versus FOLFOX-4. After patient accrual had begun, the trial design was amended in 2003 after bevacizumab phase III data became available. The resulting 2 x 2 factorial design randomly assigned patients to XELOX versus FOLFOX-4, and then to also receive either bevacizumab or placebo. We report here the results of the analysis of the XELOX versus FOLFOX-4 arms. The analysis of bevacizumab versus placebo with oxaliplatin-based chemotherapy is reported separately. The prespecified primary end point for the noninferiority analysis was progression-free survival.

Results: The intent-to-treat population comprised 634 patients from the original two-arm portion of the study, plus an additional 1,400 patients after the start of the amended 2 x 2 design, for a total of 2,034 patients. The median PFS was 8.0 months in the pooled XELOX-containing arms versus 8.5 months in the FOLFOX-4-containing arms (hazard ratio [HR], 1.04; 97.5% CI, 0.93 to 1.16). The median overall survival was 19.8 months with XELOX versus 19.6 months with FOLFOX-4 (HR, 0.99; 97.5% CI, 0.88 to 1.12). FOLFOX-4 was associated with more grade 3/4 neutropenia/granulocytopenia and febrile neutropenia than XELOX, and XELOX with more grade 3 diarrhea and grade 3 hand-foot syndrome than FOLFOX-4.

Conclusion: XELOX is noninferior to FOLFOX-4 as a first-line treatment for MCRC, and may be considered as a routine treatment option for appropriate patients.