Potential clinical applications of halichondrins in breast cancer and other neoplasms.

Halichondrin B is a large polyether macrolide found in a rare Japanese sponge, Halichondria okadai and has been shown to have anticancer activity. Eribulin mesylate is a completely synthetic analog of halichondrin B with a unique mechanism of action relative to other antimicrotubule agents. This new agent has demonstrated activity in preclinical studies, and it is being developed for the treatment of different tumor types. Eribulin has been approved by the United States Food and Drug Administration and the European Medicines Agency as late-line therapy for metastatic breast cancer patients previously treated with an anthracycline and a taxane. It has demonstrated superiority over other treatments in overall survival (OS) (hazard ratio: 0.81, P = 0.041), leading to its regulatory approbation for clinical practice use. Median OS for the eribulin-treated group was 13.1 months versus 10.6 months in the physician's treatment-of-choice group. Eribulin demonstrated a manageable toxicity profile. Most common adverse events associated with treatment were mild neutropenia and fatigue, mainly of grade 1 or 2. In contrast to other antimicrotubule agents, eribulin has a relatively low incidence of peripheral neuropathy and alopecia. Eribulin has been extensively studied in breast cancer and is currently being developed for treatment of other cancer types. Eribulin has demonstrated activity in Phase II trials in non-small cell lung cancer, pancreatic cancer, urothelial tract cancer, and sarcomas. Further studies in these cancers are ongoing. This article reviews pharmacology, mechanism of action, pharmacokinetics and efficacy of eribulin in breast cancer and other neoplasms.