The chemotherapy drugs docetaxel, marketed as Taxotere, and paclitaxel are considered the gold standard for treating breast cancer that has spread to other parts of the body.
Abraxane, which is a variant of paclitaxel, uses a different, solvent-free "delivery" system to get the drug into the body.
For the study, 302 women who had not previously been treated for advanced breast cancer were randomized into one of four treatment arms. Three of the four groups were given Abraxane, administered one of three ways: every three weeks, weekly at a lower dose for three weeks with the fourth week off, or weekly at a higher dose for three weeks with the fourth week off. The fourth group was given Taxotere every three weeks at the standard dose.
Abraxane was found to be generally superior to Taxotere in response rates, but the most striking results were seen when the drug was given on a weekly schedule with the fourth week off.
"The anti-tumor effect was greater, and this is how the drug is very commonly used in practice today, although it's approved as an every-three-week drug," Gradishar said. "That also translated into a longer time until the disease progressed."
Abraxane also had fewer side effects than Taxotere, the researchers found. All-in-all, the authors stated, the results suggest that Abraxane may be a preferable first choice for treating this group of patients.
A phase 3 trial comparing the same set of drug regimens is being planned.
One expert noted that the weekly regimen appeared the best.
"This is slightly disappointing in that the every-three-weeks schedule was not as good. That's more convenient for patients," said Dr. Jennifer Eng-Wong, an assistant professor of oncology at Georgetown's Lombardi Comprehensive Cancer Center in Washing
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