Women with breast cancer who are treated with Sanofi-Aventis’ Taxotere (docetaxel) have significantly better survival than those who receive the related drug paclitaxel, according to the results of a Phase III study.

The trial, reported in the Journal of Clinical Oncology (August 20), showed that women with advanced breast cancer that had progressed despite prior chemotherapy and who received Taxotere lived for a median of 15.4 months, compared to 12.7 months for the paclitaxel group.

The difference was only just statistically significant, with p value of 0.03. But this in itself is something of an achievement because it is rare for comparative studies to uncover significant differences in survival in advanced breast cancer, said Stephen Jones of Baylor-Sammons Cancer Centre in Dallas, Texas, one of the oncologists who took part in the study.

Meanwhile, the data for time to progression were more compelling, with women who received Taxotere experiencing 5.7 months of progression free life, compared to 3.6 months for the paclitaxel group, a difference that was strongly significant (p<0.0001).

"This is the first clinical trial to directly compare these extensively used taxanes,” said Jones, who added that this backs up preclinical evidence that there is a difference between the two drugs.

But in an editorial accompanying the study, Clifford Hudis of Memorial Sloan-Kettering Cancer Centre asks how the results of this trial should be interpreted, given that the clinical landscape in breast cancer treatment has been changed by the introduction of newer drugs - such as Roche/Genentech’s Herceptin (trastuzumab) and Avastin (bevacizumab) Eli Lilly’s Gemzar (gemcitabine), Roche’s Xeloda (capecitabine) and Pierre Fabre’s Navelbine (vinorelbine) – and updated taxane dosing regimens?

Hudis notes that the trial clearly shows that Taxotere is superior to paclitaxel in the regimens used, which were standard practice in 1994 when the study was initiated, albeit with a slight increase in toxicity for Sanofi-Aventis’ drug. However, given the changes in breast cancer treatment that have occurred since then, it becomes hard to translate the findings’ relevance to current practice, he concludes.