Eisai’s breast cancer drug Halaven® (eribulin) failed to show superiority over capecitabine (Xeloda®) therapy in a Phase III trial comparing the drugs in the treatment of women with locally advanced or metastatic breast cancer. Halaven is already approved in the U.S., EU, Switzerland, Japan, and Singapore, for the treatment of patients with breast cancer who have previously received at least two chemotherapeutic regimens for metastatic disease and whose prior therapy included an anthracycline and a taxane.
The latest Phase III study directly compared Halaven with capecitabine as an earlier, second line of therapy than the FDA approved indication (third-line therapy). The trial (study 301) included 1,102 women with locally advanced or metastatic breast cancer who had previously received anthracyclines and taxanes in either a new adjuvant setting or for locally advanced or metastatic disease.
The results failed to demonstrate any significant benefits of the nontaxane microtubule dynamics inhibitor over capecitabine in terms of overall survival or progression-free survival. There was a trend toward improved overall survival for patients receiving Halaven, but it didn’t reach statistical significance. Eisai says it will now evaluate the data in detail before deciding on any next steps.
Halaven is a synthetic analog of halichondrin B, a natural product originally isolated from the marine sponge Halichondria okadai. The drug is separately undergoing Phase III trials for the treatment of sarcoma, and is poised to start in Phase III development against non-small cell lung cancer. Halaven was launched in the U.S. during 2010, and achieved U.S. sales of ¥2.2 billion (nearly $28 million) in 2011.