A Phase III randomized trial finds that a new chemotherapy agent, eribulin mesylate, extends median overall survival by about 2.5 months among women with locally recurrent or metastatic breast cancer who had already been heavily treated with conventional therapies.

"Until now, there hasn't been a standard treatment for women with such advanced breast cancer. For those who have already received all of the recognized treatments, these are promising results," said lead author Christopher Twelves, M.D., professor of clinical cancer pharmacology and oncology, and Head of the Clinical Cancer Research Groups at the Leeds Institute of Molecular Medicine and St. James's Institute of Oncology in Leeds, U.K. "These findings may establish eribulin as a new, effective option for women with heavily pre-treated metastatic breast cancer."

Eribulin mesylate is a new type of "microtubule dynamics inhibitor" that affects cell division; the drug is derived from a marine sponge. The international, multicenter trial, called EMBRACE, is the first to compare eribulin mesylate to "treatment of physician's choice" in women with locally recurrent or metastatic breast cancer who had already received an average of four prior chemotherapy drugs, such as anthracyclines or taxanes. Because no single chemotherapy regimen is standard for these women, physicians chose which treatment to give patients in this study's control arm, to reflect real-life choices.

Dr. Twelves and his colleagues compared overall survival among 762 patients with metastatic breast cancer who were randomized to receive either eribulin (508 women) or their physician's choice of therapy (254 women), which was almost always another chemotherapy. The median survival for the eribulin group was significantly longer: 13.1 months versus 10.7 months. The study's secondary endpoints (progression-free survival and objective response rate) also favored eribulin, which was generally well tolerated.

Disclosures: Christopher Twelves, Consultant or Advisory Role, Eisai, Expert Testimony, Eisai; Joanne Blum, Consultant or Advisory Role, Eisai; Linda Vahdat, Consultant or Advisory Role, BMSO, Eisai, Research Funding, BMSO, Eisai, Research Funding, ImClone Systems; Corina Akerele, Employment/Leadership Position, Eisai; Seth Seegobin, Employment/Leadership Position, Eisai; Jantien Wanders, Employment/Leadership Position, Eisai; Javier Cortes, Consultant or Advisory Role, Eisai.

This abstract was presented or published pursuant to an exception to the ASCO Conflict of Interest Policy.