Breast Cancer Drug Eribulin Extends Survival

Study Shows Drug for Advanced Breast Cancer Extends Life 2.5 Months Longer Than Current Treatments

By Kathleen Doheny
WebMD Health News

Reviewed by Laura J. Martin, MD

March 2, 2011 -- The new breast cancer drug eribulin (Halaven) extends survival two and a half months longer than other therapies for advanced breast cancer, researchers report.

''This will rapidly emerge as the standard tried-and-tested option," researcher Chris Twelves, MD, of St. James University Hospital in the U.K., tells WebMD.

The new chemotherapy drug, approved in November by the FDA, was compared to existing treatments typically offered to women who have locally recurrent breast cancer or breast cancer that has spread despite up to five previous regimens of chemotherapy, Twelves says.

''There was a significant prolongation of survival in the group of women who received eribulin," he tells WebMD.

Those on eribulin lived a median of 13.1 months (half survived longer, half less) compared to a median survival time of 10.6 months for women treated with other therapies.

While the increase may not seem like much, Twelves says, it may allow women to enjoy life milestones such as anniversaries, birthdays, and graduations.

"I need to emphasize this isn't curative treatment," Twelves says. His team's intent was to compare overall survival, challenging the common wisdom that improving overall survival in this group of women is unrealistic.

The role of the treatment, he says, is to extend survival a bit longer when other treatment options have failed.

The study is published in The Lancet. Twelves consults for Eisai Inc., which makes the drug and funded the trial.

Comparing Breast Cancer Treatments

In the study, known as the EMBRACE trial, Twelves and his colleagues randomly assigned 762 women either to the new drug or to the treatment chosen by their doctors as predicted to have the best effect. The assignments were made from late 2006 to late 2008 and involved patients from 135 centers in 19 countries.

Of those 762 women, 508 received eribulin and 254 received their doctor's treatment choice. That could be either chemotherapy with a single agent, biological or hormonal treatment, radiotherapy, or supportive care. None got supportive care alone, and most, 96%, got chemotherapy.

The eribulin was administered intravenously for two to five minutes on days one and eight of a 21-day cycle. The median duration of treatment was about four months. For the other group, the median length of treatment ranged from about one to two months.

The researchers wanted to look primarily at overall survival between the two groups. The 2.5-month difference with eribulin was significant, they found.

They also found that nearly 54% of the eribulin group and 43% of the other group survived a year.

When they looked at progression free survival -- those women who survived but also did not have cancer progression -- they found the median was 3.7 months for those on eribulin and 2.2 months for those on other treatments.

Serious adverse events occurred in 25% of the eribulin patients and 26% of those on other treatments. Five percent of the women on eribulin developed febrile neutropenia, a potentially life-threatening problem of low white blood cells counts, fever, and infections, compared to 2% of the other group.

Side effects of weakness and fatigue were the most commonly reported in both groups, with 52% of those on eribulin and 40% of those in other groups reporting these symptoms. Tingling, prickling, and numbness of the fingers and toes (peripheral neuropathy) was the most common reason for women to drop out of the eribulin group, with 24 patients doing so.

The drug, derived from sea sponges, works by targeting the scaffolding within a cell, Twelves tells WebMD. "When a cell divides, the scaffolding helps it. What the eribulin does is interfere with the construction of the scaffolding and stops the cancer cell from dividing."

Finding a Place in Cancer Treatment

"It's very well tolerated," says Joanne Mortimer, MD, director of the Women's Cancers Program at the City of Hope Comprehensive Cancer Center in Duarte, Calif., who has used the drug in about a dozen of her patients. She has no ties to Eisai Inc.

She agrees with Twelves that the new drug will become the new standard for women whose previous breast cancer treatments have not worked.

"Yes, people are fatigued, but the fatigue doesn't seem to be as bad as some chemotherapy treatments we use," she says. "There is hair loss but no one [of her patients so far] has required a wig."

In a comment linked to the study, researchers from Dana-Farber Cancer Institute and Harvard Medical School say many questions remain about the treatment, including whether certain patients or tumor subtypes may especially benefit and at what point would treatment be futile.

They acknowledge, however, that the trial ''provides much needed, high-level evidence of chemotherapy use in patients with heavily treated breast cancer."

Judee Shuler, a spokeswoman for Eisai, tells WebMD in an email that the company believes the drug's price reflects the value the drug brings to cancer patients and society.

The company offers an assistance program. Coverage varies by insurance plans, according to Shuler.


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SOURCES: Chris Twelves, MD, professor of clinical pharmacology and oncology and head, clinical cancer research groups, Leeds Institute of Molecular Medicine & St. James' Institute of Oncology, St. James University Hospital, Leeds, U.K.Cortes, J. The Lancet, published online March 3, 2011.Lin, N. The Lancet, published online March 3, 2011.Joanne Mortimer, MD, director of Women's Cancers Program, City of Hope Comprehensive Cancer Center, Duarte, Calif.Judee Shuler, spokeswoman, Eisai Inc., Woodcliff Lake, N.J.

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