June 7, 2010 (Chicago) -- A drug derived from sea sponges extended the lives of breast cancer patients whose cancer had come back -- despite as many as five rounds of chemotherapy -- by an average of two and a half months.
In the study of over 750 women, those who took the experimental drug eribulin lived an average of about 13 months, compared with about 10 1/2 months for women who did not take the drug.
While a few months might not sound like much, it can be a huge gain for seriously ill patients facing an imminent risk of dying, say doctors studying the drug.
"I've had women whose outlook is poor, facing [an average] survival time of about 10 months, tell me, 'I just want to make it to next year to see my child's fourth birthday, or my son's wedding,'" says study head Christopher Twelves, MD, PhD, of St. James Hospital in Leeds, England.
"Now there is a drug that we can add to their limited options," he tells WebMD.
Twelves presented results of the late-stage phase III trial at the annual meeting of the American Society of Clinical Oncology. He consults for Eisai, which makes eribulin and funded the study.
Many of the more than 200,000 women diagnosed with breast cancer in the U.S. each year now have an excellent chance of becoming long-term survivors due to better treatments developed over the past few decades.
"But about 30% will develop advanced or metastatic disease that cannot be cured with current treatments," Twelves says.
Enter eribulin, a chemotherapy drug that targets the scaffolding protecting cells, stalling cell division and causing cells to die off. Some older chemo drugs such as taxanes also act on the scaffold, but on a different part.
The new study involved 762 breast cancer patients whose tumors had spread (metastasized) despite two to five rounds of different chemotherapy drugs.
Two-thirds of the women got eribulin, which is given as a short IV infusion two days, every three weeks. The rest received whatever treatment their doctor thought was best, usually another chemotherapy drug but sometimes only supportive care to treat pain and fatigue.
Women on eribulin were 19% less likely to die, the study shows. Their cancer also stayed in check slightly longer: 3.7 months vs. 2.2 months for women on standard treatment. Tumors shrank by 30% or more in 12.2% of women on eribulin vs. 4.7% of women in the other group.
Surprisingly, among women whose tumors did shrink, the duration of response was longer for women in the standard therapy group: 6.7 months vs. 4.1 months in the eribulin group.
Twelves cautions against putting too much emphasis on that finding, given that there were only about 10 women in the standard treatment group.