Future treatment options with capecitabine in solid tumours

The oral fluoropyrimidine, capecitabine is attracting great interest in the context of tumour-selective therapy and rationally designed combination regimens. Agents such as taxanes upregulate thymidine phosphorylase (TP), and there is therefore a clear rationale for their combination with capecitabine. Preclinical studies of capecitabine/taxane combination therapy demonstrated synergistic antitumour activity and phase I studies showed encouraging efficacy. Therefore, a randomised, phase III trial (docetaxel versus docetaxel/capecitabine) has been initiated in anthracycline-refractory metastatic breast cancer patients. Recruitment is complete. In colorectal cancer, capecitabine/oxaliplatin combination therapy is promising and a phase I, dose-finding trial has been conducted in patients with refractory metastatic solid tumours. A similar trial has evaluated capecitabine/irinotecan combination treatment. Capecitabine is also being investigated as adjuvant therapy for colorectal and breast cancers. The primary objective of the ongoing X-ACT trial in almost 2000 Dukes' C colon cancer patients is to demonstrate at least equivalent disease-free survival between capecitabine and the Mayo Clinic regimen. In addition, the CALGB is planning a randomised, phase III trial of capecitabine versus doxorubicin/cyclophosphamide or cyclophosphamide/methotrexate/5-fluorouracil (CMF) as adjuvant treatment in high-risk, node-negative breast cancer patients aged >65 years.