Metastatic
breast cancer is currently incurable and the goals of
therapy focus on prolonging survival and maintaining quality of life by controlling symptoms and minimizing toxicity. Treatments for metastatic
breast cancer include chemotherapeutic agents from various classes, such as
taxanes,
vinca alkaloids,
anthracyclines and
antimetabolites. This review provides an overview of chemotherapeutic agents for the treatment of metastatic
breast cancer patients previously treated with
anthracyclines and
taxanes, focusing on a clinical evaluation of
eribulin, the most recently approved agent for the treatment of metastatic
breast cancer.
Eribulin is a synthetic derivative of
halichondrin B, a tumour
growth inhibitor found in marine sponges, which prevents microtubule growth and sequesters the
tubulin molecules into unusual aggregates, initiating apoptosis. Studies of
eribulin have shown that the
drug is effective in the treatment of previously treated metastatic
breast cancer, and has an acceptable toxicity profile. Importantly, in the phase III EMBRACE study,
eribulin treatment resulted in a survival advantage, a difficult endpoint to achieve with a single chemotherapeutic agent. An additional phase III study showed that
eribulin has similar efficacy to
capecitabine in women treated with no more than three prior
therapies. Furthermore, pre-specified exploratory analyses suggest that particular patient subgroups may have greater therapeutic benefit with
eribulin and may warrant further study to explore the potential mechanisms.