Detailed analysis of a randomized phase III trial: can the tolerability of capecitabine plus docetaxel be improved without compromising its survival advantage?

BACKGROUND

In a phase III trial, 3-weekly capecitabine (1250 mg/m(2) twice daily days 1-14) plus docetaxel (75 mg/m(2) day 1) demonstrated significantly superior overall survival to 3-weekly docetaxel (100 mg/m(2) day 1). We report a retrospective analysis of the impact of capecitabine/docetaxel dose reduction on safety and efficacy.

PATIENTS AND METHODS

Safety and efficacy data were analyzed retrospectively according to the actual doses of capecitabine and docetaxel administered.

RESULTS

More patients receiving capecitabine/docetaxel (65%) had dose reductions for adverse events than docetaxel alone (35%). In most patients requiring dose reduction with the combination (80%), capecitabine and docetaxel were simultaneously reduced to 950 mg/m(2) and 55 mg/m(2), respectively. Subsequently, there were fewer cycles (17%) with grade 3/4 adverse events than with the full doses (34%). Time to progression and overall survival appeared to be similar in patients starting the second cycle with reduced doses of capecitabine/docetaxel and those who continued to receive full doses of capecitabine/docetaxel for at least the first four cycles.

CONCLUSIONS

Capecitabine/docetaxel dosing flexibility allows management of side-effects without compromising efficacy. This retrospective analysis, as well as multiple phase II studies of taxanes with reduced-dose capecitabine, shows that reducing the starting dose of capecitabine with docetaxel is a reasonable strategy for the treatment of patients with metastatic breast cancer. In addition, reducing the dose of both agents may be appropriate.