Eisai Inc. announced that the United States Food and Drug Administration (FDA) has approved Halaven (eribulin mesylate) Injection for the treatment of patients with metastatic breast cancer who have previously received at least two chemotherapeutic regimens for the treatment of metastatic disease. Prior therapy should have included two common chemotherapy treatments, an anthracycline and a taxane, for early or advanced breast cancer. Discovered and developed by Eisai, Halaven is a non-taxane, microtubule dynamics inhibitor that is a synthetic analogue of halichondrin B, a product isolated from the marine sponge Halichondria okadai.

"Many women with metastatic breast cancer see their disease progress after receiving multiple therapies," said Linda Vahdat, M.D., Professor of Medicine, Division of Haematology & Medical Oncology at the Iris Cantor Women's Health Center at New York-Presbyterian Hospital/Weill Cornell Medical Center in New York City. "Now, with the approval of Halaven, we can offer a new option that has been shown to improve survival in women with metastatic disease."

The FDA approval of Halaven is based on results from the pivotal -phase III clinical study EMBRACE (Eisai Metastatic Breast Cancer Study Assessing Physician's Choice Versus Eribulin), which showed that patients treated with Halaven survived a median of 2.5 months longer than patients who received a single-agent therapy chosen by their physician (Treatment of Physician's Choice). Overall survival was 13.12 months with Halaven versus 10.65 months with TPC (p=0.041). In an updated survival analysis, conducted when 77 percent of events had been observed, the result was consistent with the primary analysis.

The most common side effects (incidence = 25 per cent) reported by patients receiving Halaven were neutropenia (low white blood cells), anemia (low red blood cells), asthenia/fatigue (weakness/tiredness), alopecia (hair loss), peripheral neuropathy (numbness, tingling or burning in the hands and feet), nausea and constipation. The most common serious side effects reported in patients receiving Halaven were neutropenia with or without fever (four percent and two percent, respectively). Severe weakness/tiredness occurred in 10 percent of patients receiving Halaven. The most common side effect resulting in discontinuation of treatment with Halaven was peripheral neuropathy (five percent).

"The FDA approval of Halaven is significant news for the metastatic breast cancer community in an area of unmet medical need," said Lonnel Coats, president & CEO, Eisai Inc. "This achievement is consistent with our human health care mission of striving to produce therapies that may help make a difference in the lives of patients and their families."

EMBRACE was an open-label, randomized, global, multi-centre study designed to compare overall survival in patients treated with Halaven versus a Treatment of Physician's Choice (TPC arm). TPC was defined as any single-agent chemotherapy, hormonal treatment or biologic therapy approved for the treatment of cancer; or palliative treatment or radiotherapy administered according to local practice. The study included 762 patients with metastatic breast cancer who previously had been treated with an average of four prior chemotherapies. The vast majority of patients in the TPC arm received chemotherapy.

"This approval is encouraging news for women with metastatic breast cancer," said Liz Thompson, president of Susan G. Komen for the Cure, the global leader in breast cancer advocacy. "This is a challenging disease and the possibility of improved survival is meaningful to patients and their families."

Halaven is expected to be available in the United States within 10 business days after approval. In addition, Eisai has submitted regulatory applications for approval of eribulin mesylate for the treatment of metastatic breast cancer to regulatory agencies in Japan, the European Union, Switzerland and Singapore.

Halaven is indicated for the treatment of patients with metastatic breast cancer who have previously received at least two chemotherapeutic regimens for the treatment of metastatic disease. Prior therapy should have included an anthracycline and a taxane either in the adjuvant or metastatic setting. A non-taxane, microtubule dynamics inhibitor, Halaven is derived from the marine sponge Halichondria okadai. It is believed to work by inhibiting the growth phase of microtubule dynamics without affecting the shortening phase and sequesters tubulin into nonproductive aggregates.

Eisai Inc. was established in 1995 and is ranked among the top 20 United States pharmaceutical companies (based on retail sales). The company began marketing its first product in the United States in 1997 and has rapidly grown to become a fully integrated pharmaceutical business with fiscal year 2009 (year ended March 31, 2010) sales of approximately $3.9 billion.