Consistent efficacy and safety of gemcitabine-paclitaxel in patients with metastatic breast cancer: a retrospective comparison of East Asian and global studies

Abstract

Aims: The incidence of breast cancer in China is increasing at a rate greater than the global average. For treatment of metastatic breast cancer, a phase 3 trial of 529 patients (study JHQG) found that the combination of gemcitabine, a cytotoxic nucleoside analog, and paclitaxel, a taxane, significantly improved both overall and progression-free survival compared with paclitaxel monotherapy. As ethnic differences in the safety and efficacy of some anticancer therapies have been reported, this review provides oncologists treating East Asian patients with an evidence base to extrapolate results of the predominately Caucasian phase 3 JHQG study to their patients.

Methods: Three phase 2 studies in Chinese or Japanese patients with metastatic breast cancer are reviewed with reference to the global study JHQG. The results of pharmacokinetic, efficacy and safety analyses are descriptively compared between the global and Asian studies.

Results: Peak and total drug exposure values differed by less than 10% across the studies. Response rate, overall and progression-free survival values were similar, although values from the Asian studies for each of these parameters were slightly higher. Asian patients had higher rates of hematologic toxicities but lower rates of other adverse events.

Conclusion: Examination of the data from three studies of the gemcitabine-paclitaxel combination reveals no clinically significant ethnic differences in efficacy and safety between East Asian patients and their global counterparts. Given its demonstrated efficacy and safety profile, the gemcitabine-paclitaxel regimen should be one of the standard treatments for East Asian patients with metastatic breast cancer.

Keywords: Chinese; Japanese; combination chemotherapy; ethnic variability; pharmacokinetics.