Eribulin (Halaven?, Eisai Europe Ltd) 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 Sweden, Denmark and Finland after approval by the European Drug Agency (EU) for the whole EU area by March 24, 2011. Prior therapy should have included two common types of chemotherapy, an anthracycline and a taxane, unless patients were not suitable for these treatments.[1]

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]

Breast Cancer in the Nordic Countries
Breast cancer is the most common cancer in women in Nordic countries representing 27% of cancer cases in 2008 corresponding to an annual incidence of approximately 17,300 women getting a breast cancer diagnosis per year.[4] It accounts for around 15% of female deaths from cancer.[4] The prognosis for primary breast cancer has improved markedly over the years, while the outcome for metastatic breast cancer is still bleak, the approved indication for eribulin. Around five percent of breast cancer patients present with advanced disease with distant metastases at first diagnosis,[5] and 20 – 30%of women diagnosed with early or localised breast cancer will eventually relapse and develop metastatic or advanced disease.[6]

“The launch of eribulin in Sweden, Denmark and Finland will be an interesting and potentially important amendment to the present therapy armamentarium for the management of patients failing on conventional therapies,” commented Professor Jonas Bergh, Karolinska Institutet and University Hospital, Sweden. “Compared to current treatment options, eribulin is the first single chemotherapy agent to have demonstrated a statistically significant improvement in median overall survival for many patients who have already received several lines of therapy for advanced breast cancer.”

European approval
Eribulin received European Commission approval 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) which showed that patients treated with Halaven 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]

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The EMBRACE study was an open-label, randomised, global, multi-centre, parallel two-arm 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 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]

Reported adverse reactions
In this study, the most common reported adverse reactions among patients treated with eribulin were asthenia (fatigue), neutropenia, alopecia (hair loss), peripheral neuropathy (numbness and tingling in arms and legs), nausea and constipation.[3]

The most common serious side effect reported in patients receiving eribulin was neutropenia, with or without fever (occurring in 45% and 5% of patients respectively).[3] The most common adverse reaction resulting in discontinuation of treatment with eribulin was peripheral neuropathy (5%).[3]

Metastatic Breast Cancer
In 2008, approximately 17,300 women were diagnosed with breast cancer in the Nordic region, and approximately 4,250 women died from breast cancer.[4] Yearly incidence of breast cancer per country include 6,315 women (Sweden), 4,149 women (Denmark) and 3,922 women (Finland).[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[5] and others with local and regional disease may eventually develop metastatic disease.[6] An estimated 13 percent of women presenting with metastatic breast cancer will survive beyond five years.[5]

[1] Summary of Product Characteristics Halaven (updated March 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] NORDCAN 2009. Last accessed 4 April 2011.
[5] Cancer Research UK. Statistics and outlook for breast cancer. Last accessed 1 April 2011.
[6] O’Shaughnessy, J. Extending Survival with Chemotherapy in Metastatic Breast Cancer. The Oncologist. 2005;10;20-29

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