By Amanda Gardner
TUESDAY, May 26 (HealthDay News) -- A new study affirms that the chemotherapy drug Abraxane is more effective, with less troublesome side effects, than the current drug of choice for metastatic breast cancer.
When compared with Taxotere, Abraxane extended the time before a recurrence by almost seven months, effectively doubling survival. Both are members of a class of drugs known as taxanes.
The study, which was a phase 2 trial, was funded by Abraxis BioScience, which makes Abraxane. The findings are reported in the May 26 issue of the Journal of Clinical Oncology.
"This data, which has been presented at national meetings, reaffirms that Abraxane is a very active drug, is well-tolerated and appears to have a greater anti-tumor effect than what you would see with what had been presumed to be the most active drug," said Dr. William Gradishar, director of breast medical oncology at the Robert H. Lurie Comprehensive Cancer Center at Northwestern University. "This probably will encourage people to either use or try Abraxane, as opposed to other taxanes."
Another expert agreed.
"This is a major advance. It's a very well-tolerated drug and has low toxicity. We've used this regimen for a number of years now and it's very good," said Dr. Jay Brooks, chairman of hematology/oncology at Ochsner Health System in Baton Rouge. "We're now beginning to realize that many drugs given more frequently at lower doses is not only less toxic but has less side effects. It still doesn't cure people but it's a kinder, gentler way of delivering drugs, although it is more expensive."
Abraxane (nab-paclitaxel) was approved for use in the United States in 2005.
"There has been sort of a preconceived notion that Taxotere is the most potent anti-cancer therapy for metastatic breast cancer, certainly among taxanes," Gradishar said. "That's why this comparison was being made." Gradishar, who was the lead author for the study, is also a consultant to Abraxis BioScience.
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 Washington, D.C. "But it doesn't look like it's the right way to go."
Other reports in the Journal of Clinical Oncology include:
- A study from National Cancer Institute investigators that found that people with early-stage breast cancer who have high levels of C-reactive protein and serum amyloid A -- both markers of inflammation -- were two to three times more likely to die of their disease or see their cancer return than people with lower levels of the proteins.
- New guidelines from the American Society of Clinical Oncology stating that women at a heightened risk of developing breast cancer might benefit from the drug Evista (raloxifene) in addition to tamoxifen. Previous guidelines recommended only tamoxifen.