Purpose: Capecitabine has demonstrated high efficacy as first-line treatment for metastatic colorectal cancer (MCRC). Oxaliplatin shows synergy with fluorouracil (FU), with little toxicity overlap. The XELOX regimen (capecitabine plus oxaliplatin), established in a previous dose-finding study, should improve on infused oxaliplatin with FU and leucovorin (FOLFOX) regimens. The present studies further characterize efficacy and safety of the XELOX regimen.
Patients and methods: The antitumor activity of XELOX was investigated in a colon cancer xenograft model. Patients with MCRC received first-line XELOX in 3-week treatment cycles: intravenous oxaliplatin 130 mg/m(2) (day 1) followed by oral capecitabine 1,000 mg/m(2) twice daily (day 1, evening, to day 15, morning).
Results: A preclinical study confirmed that capecitabine has supra-additive activity with oxaliplatin. In the clinical study, 53 of 96 patients (55%) achieved an objective response, and 30 (31%) experienced disease stabilization for >/= 3 months following treatment. After 24 months' minimum follow-up, median time to disease progression (TTP) and median overall survival were 7.7 and 19.5 months, respectively. XELOX safety was predictable and similar to the FOLFOX4 regimen, except that myelosuppression was uncommon with XELOX (grade 3 or 4 neutropenia, 7%). Most adverse events were mild to moderate, the most common being acute sensory neuropathy (85%). Sixty-day, all-cause mortality was 2%.
Conclusion: XELOX is a highly effective first-line treatment for MCRC. Response rates, TTP, and overall survival are similar to those observed with FU/leucovorin/oxaliplatin combinations. XELOX provides a more convenient regimen, likely to be preferred by both patients and healthcare providers. Capecitabine has the potential to replace FU/LV in combination with oxaliplatin for MCRC.