Eribulin (Halaven?, Eisai Inc), a novel treatment for patients with locally advanced or metastatic breast cancer who have progressed after at least two chemotherapeutic regimens for advanced disease is launched today in the United Kingdom. Prior therapy should have included two common types of chemotherapy, an anthracycline and a taxane, unless patients were not suitable for these treatments.[1]

Breast cancer is now the most common cancer in the UK and the lifetime risk of being diagnosed with breast cancer is 1 in 8 for women in the UK.[4] In 2008, almost 47,700 women were diagnosed with breast cancer, around 130 women a day.[4]

Metastatic breast cancer is an advanced stage of the disease that occurs when cancer spreads beyond the breast to other parts of the body. Approximately 5% of women with breast cancer will have metastatic disease at the time of diagnosis[7] and others with local and regional disease may eventually develop metastatic disease.[6] An estimated 13% of women presenting with metastatic breast cancer will survive beyond five years.[7]

Discovered and developed by Eisai, eribulin is a non-taxane, microtubule dynamics inhibitor and a synthetic analog of halichondrin B, a natural product isolated from the marine sponge Halichondria okadai.[2] It is a new class of agent and the first, single-agent chemotherapy to demonstrate a statistically significant overall survival benefit in patients with heavily pre-treated advanced breast cancer compared to currently used treatments. [1,3] Patients treated with eribulin survived a median of 2.5 months longer than patients who received treatment of physician’s choice (overall survival of 13.1 months versus 10.6 months, respectively, p=0.041).[1,3]

Breast cancer is the most common cancer in the UK.[4] It accounts for around 16% of female deaths from cancer, the second most common cause of female cancer death after lung cancer.[5] Thirty percent of women diagnosed with early or localised breast cancer will eventually relapse and develop metastatic or advanced disease.[6]

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“Eribulin addresses an urgent need for new treatment options for women with advanced breast cancer who have previously received multiple treatments,” says Dr Andrew Wardley, Consultant Medical Oncologist and Co-Chair of the Breast Group at The Christie Hospital in Manchester.

Eribulin received European Commission approval on 17 March 2011 based on the results of the global Phase III EMBRACE study (Eisai Metastatic Breast Cancer Study Assessing Treatment of Physician’s Choice (TPC) Versus Eribulin E7389).

The Global Phase III Clinical Study (EMBRACE) EMBRACE was an open-label, randomised, global, multi-centre, parallel two-arm study designed to compare overall survival in patients treated with eribulin 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 at least two and a maximum of five prior chemotherapies, including an anthracycline and a taxane. The vast majority (97%) of patients in the TPC arm received chemotherapy.[3]

The most common adverse reactions (incidence greater than or equal to 19%) among patients treated with eribulin were asthenia (fatigue), neutropenia, alopecia (hair loss), peripheral neuropathy (numbness and tingling in arms and legs), nausea and constipation. The most common serious side effect reported in patients receiving eribulin was neutropenia, with or without fever (occuring in 45% and 5% of patients respectively).[3] The most common adverse reaction resulting in discontinuation of treatment with eribulin was peripheral neuropathy (five percent).[3]

“As a charity that supports patients living with metastatic (secondary) breast cancer, we have heard from many UK women that they feel there are limited treatment options available to them. The UK launch of eribulin is a step towards a drug being made available to these patients which could help give them precious extra time,” commented Maria Leadbeater, clinical nurse specialist – metastatic (secondary) breast cancer, Breast Cancer Care.

For more information:
[1] Summary of Product Characteristics (SPC) Halaven (updated March 2011). Last accessed May 24, 2011.
[2] Jordan MA et al. The primary antimitotic mechanism of action of the synthetic halichondrin E7389 is suppression of microtubule growth. Mol Cancer Ther 2005;4:1086-95
[3] Cortes J, O’Shaughnessy J, Loesch D, et al. Eribulin monotherapy versus treatment of physician’s choice in patients with metastatic breast cancer (EMBRACE): a phase 3 open-label randomised study. The Lancet. 2011; 377: 914 -923
4] Cancer Research UK. Cancer Statistics – Key Facts. Last accessed May 24, 2011.
[5] Cancer Research UK. Breast cancer mortality statistics 2004. Last accessed May 24, 2011
[6] O’Shaughnessy. Extending Survival with Chemotherapy in Metastatic Breast Cancer. The Oncologist. 2005;10;20-29
[7] Cancer Research UK. Statistics and outlook for breast cancer. Last accessed May 24, 2011.

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