Eisai has filed eribulin with regulators in Japan, the USA and the European Union for the treatment of locally advanced or metastatic breast cancer.

The Japanese drugmaker says that the submission for eribulin, also known as E7389, are based on data from a global Phase III study known as EMBRACE. In the trial, 762 women were treated either with eribulin (administered intravenously over two to five minutes on days one and eight every 21 days) or with “treatment of physician's choice”. The latter was defined as any single agent chemotherapy, hormonal treatment or biological therapy approved for cancer, palliative treatment or radiotherapy administered according to local practice.

Eisai says the results showed that the trial met its primary endpoint of demonstrating a statistically significant improvement in overall survival in eribulin-treated patients compared with the other treatments. The most frequent adverse events reported by patients treated with eribulin were fatigue, neutropenia, alopecia, nausea and peripheral neuropathy.

News of the filing, which is as scheduled, is a major boost for Eisai, coming days after the Tokyo-based group revealed that plans to submit its investigational severe sepsis drug eritoran for approval by mid-2010 have suffered a setback. An independent data monitoring committee said the firm needs to enrol another 500 patients in a late-stage study, which means that a filing for eritoran is unlikely to take place until mid-2011.

Eisai is hoping that eribulin, which belongs to a class of antineoplastic agents, the halichondrins, which are derived from the marine sponge Halichondria okadai, will help soften the loss of US patent protection on its Alzheimer's disease drug Aricept (donepezil) in November. The latter, which is co-marketed with Pfizer, is comfortably Eisai’s biggest earner.