Capecitabine is an oral fluoropyrimidine that mimics continuous infusion
5-fluorouracil and generates
5-fluorouracil preferentially at the
tumor site. It is activated via a three-step enzymatic pathway, the final step of which requires
thymidine phosphorylase, an enzyme that is significantly more active in
tumor than normal tissue. As an oral agent,
capecitabine is more convenient for patients and medical personnel, and avoids the complications associated with venous access. This paper reviews the development and clinical experience of
capecitabine in
breast cancer treatment. Clinical trials have established the efficacy and tolerability of
capecitabine in anthracycline- and
taxane-pretreated metastatic
breast cancer, showing that
capecitabine is an effective therapy for patients who have exhausted all established treatment options. Moreover, randomized, phase II studies have demonstrated that
capecitabine is effective in anthracycline-pretreated patients and as first-line therapy for metastatic
breast cancer. In addition to its confirmed efficacy, the favorable safety profile of
capecitabine, particularly the low myelosuppression rate, makes it an attractive agent for incorporation into combination regimens. Therefore numerous trials have assessed the feasibility of
capecitabine-containing regimens, and have shown promising results.
Capecitabine is an important new treatment option for
breast cancer patients, and ongoing clinical trials should further define its role in a range of settings.