Dr. O'Shaughnessy on Eribulin in Metastatic Breast Cancer

Joyce A. O’Shaughnessy, MD, the Co-Director of Breast Cancer Research at the Baylor Charles A. Sammons Cancer Center; Texas Oncology, PA/US Oncology, Dallas, Texas, reviews findings from Study 301, which compared eribulin mesylate (Halaven) to capecitabine for patients with locally advanced or metastatic breast cancer.

In the trial, 1102 women received eribulin or capecitabine as a first-, second-, or third-line treatment. However, O'Shaughnessy notes, the majority of the patients had received a prior anthracycline, making the trial essentially a second-line comparison.

Overall, the results were equivocal for the primary endpoint of overall survival (OS). Despite this, O'Shaughnessy believes the trial was positive for eribulin, since it demonstrated equivalence to one of the best agents in this setting. Additionally, she adds, a subset analysis revealed that treatment with eribulin prolonged OS by nearly 5 months more than capecitabine in patients with triple negative breast cancer.

An observational trend favoring eribulin was observed for OS; however, no difference was noticed for progression-free survival (PFS). This is similar to observations made in the EMBRACE trial, which compared eribulin to physician's choice in patients with heavily pretreated metastatic breast cancer. These data suggest that eribulin does not affect OS through PFS, instead, O'Shaughnessy believes, eribulin may sensitize the tumor to other cytotoxic agents.

In general, O'Shaughnessy notes, Study 301 was an interesting trial, which provides support for moving eribulin forward in the sequence to the second-line of treatment in metastatic breast cancer.