Japanese drugmaker Eisai will no doubt be celebrating news that its marine-derived drug Halaven has been cleared for use in the all-important US market in women with late-stage breast cancer.

Specifically, the US Food and Drug Administration has stamped its seal of approval for the use of Halaven (eribulin mesylate) in patients with metastatic breast cancer who have already received two courses of treatment with anthracycline- and taxane-based chemotherapy.

The active ingredient of Halaven belongs to a class of antineoplastic agents, the halichondrins, which are derived from the marine sponge Halichondria okadai, and the injectable is believed to work by inhibiting cancer cell growth.

The drug’s approval was based on study with 762 women that clearly demonstrated its potential benefit to patients, with data showing the median overall survival for women taking Halaven to be 13.1 months versus 10.6 months for those given a single agent comparator therapy.

The potential market for Halaven is huge – it is estimated that more than 207,000 women will be diagnosed with breast cancer this year alone, and that nearly 40,000 will die from the disease, highlighting the stark need for new and effective therapies.

Important new option

But treatment choices remain limited, particularly for women with aggressive forms of the disease who have already received other therapies, noted Richard Pazdur, director of the Office of Oncology Drug Products in the FDA’s Center for Drug Evaluation and Research, and he added that Eisai’s drug, which shows “a clear survival benefit”, is “an important new option for women”.

Halaven will be competing for US market share against Swiss drugmaker Roche’s Xeloda (capecitabine) and Bristol-Myers Squibb’s Ixempra (ixabepilone), but Eisai will be hoping that the drug will make enough sales to cushion the blow from the loss of patent protection on its Alzheimer's disease drug Aricept (donepezil) – its top earner – in the US this month.