EISAI ANNOUNCES JAPAN LAUNCH OF ANTICANCER AGENT HALAVEN®

EMBRACE was an open-label, randomized, multi-center, parallel two-arm study designed to compare overall survival (OS) in patients treated with Halaven® versus a Treatment of Physician's Choice (TPC). The study included 762 patients with locally recurrent or 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. Patients were randomized in a 2:1 ratio to receive either Halaven or TPC. 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 vast majority (97%) of patients in the TPC arm received chemotherapy. A protocol prespecified analysis demonstrated that patients treated with Halaven survived a median of 2.5 months longer than patients who received TPC (OS of 13.1 months versus 10.6 months, respectively; Hazard Ratio [HR] 0.81; p=0.041).

An updated analysis of overall survival (not protocol prespecified) in the EMBRACE study was performed at the request of European and U.S. regulatory authorities. These results demonstrated an increase of 2.7 months in overall survival for Halaven® compared with TPC (OS of 13.2 months versus 10.5 months, respectively; HR 0.81; p=0.014). Data from this analysis was presented at the 33rd Annual San Antonio Breast Cancer Symposium, held in December 2010, and confirmed the overall survival benefits of Halaven® as well as no change in safety profile.

The most common adverse reactions (incidence greater than or equal to 25%) among patients treated with Halaven® were asthenia (fatigue), neutropenia, anemia, alopecia (hair loss), peripheral neuropathy (numbness and tingling in arms, legs and other parts of the body), nausea and constipation. The most common serious side effects reported in patients receiving Halaven were neutropenia with or without fever (4% and 2%, respectively). The most common adverse reaction resulting in discontinuation of treatment with Halaven® was peripheral neuropathy (5%).

Study 221 was a multicenter, open-label trial conducted in advanced or recurrent breast cancer patients previously treated with an anthracycline and a taxane. The study demonstrated a high response rate of 21.3% (response observed in 17 out of 80 evaluable patients), and showed that eribulin has a favorable tolerability profile.

Halaven®, a non-taxane, microtubule dynamics inhibitor with a novel mechanism of action, belongs to a class of antineoplastic agents, the halichondrins, which are natural products isolated 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 sequestering tubulin into nonproductive aggregates.

Synthesizing Halaven® is an extremely difficult and complex process, involving some 62 steps to achieve total synthesis. Halaven® has a molecular weight of 826, including 19 chiral carbons, which means the theoretical number of stereoisomers is 2¹⁹, or a possible 524,000, making stereocontrol potentially extremely difficult. However, due to Eisai's advanced technological capabilities, it was possible to stereoselectively control all synthetic reactions and commercially synthesize Halaven®.

Approved in the United States in November 2010, in Singapore in February 2011, and in the European Union the following March, Halaven® is currently under regulatory review in Canada and is being developed in numerous other countries such as those in Asia and other emerging regions. Eisai is currently conducting late stage clinical trials investigating the potential of Halaven® as a single-agent therapy in the treatment of other types of cancer such as breast cancer with fewer prior treatments, non-small cell lung cancer, sarcoma, and prostate cancer.

Breast cancer is the leading cause of cancer death among women, with approximately 60,000 patients in Japan being newly diagnosed with the disease each year. As the incidence rate starts to rise when women are in their thirties, with a peak incidence among women in their late forties or early fifties, breast cancer poses a compelling problem and constitutes and area with high unmet medical needs.

Nowadays, the number of patients diagnosed with breast cancer is increasing in accordance with advancements in the healthcare system and screening technology to promote early detection and diagnosis. It is estimated that approximately one million women worldwide are newly diagnosed with breast cancer each year, approximately 40% of which will go on to develop locally advanced or metastatic disease. Studies show that only one in five metastatic breast cancer patients is expected to live more than five years.

Breast cancer is classified into eight stages (stage: 0, I, IIa, IIb, IIIa, IIIb, IIIc, IV) based on breast lump size, whether or not the cancer has spread to the surrounding lymph nodes, and whether or not distant metastases are present. Of these stages, stages IIIb, IIIc, IV are deemed as inoperable forms of breast cancer due to the disease having metastasized or spread extensively throughout the body. Breast cancer that has metastasized to other organs (metastatic breast cancer) or that has recurred near the original site following initial treatment, such as surgical removal of the breast tumor, is referred to as recurrent breast cancer.

The number of women dying from cancer is increasing year by year, and according to the World Health Organization (WHO), approximately three million women worldwide lose their lives to the disease each year. With women taking on an increasingly more important role in society nowadays, Eisai considers it extremely meaningful to support women living with cancer and improve their quality of life.

By committing itself to “Women's Oncology,” an area of oncology that places emphasis on the perspectives of women, Eisai will stand alongside women facing cancer, while at the same time bringing them hope and making contributions to improving their quality of life.

Eisai believes that its mission is to deliver innovative new therapies to patients fighting cancer as soon as possible, by making further contributions to breast cancer patients through indication expansion and the development of additional formulations of Halaven®, and developing other therapeutic agents, such as farletuzumab, a monoclonal antibody targeting ovarian cancer, and lenvatinab, a potential treatment for thyroid and endometrial cancer. Furthermore, Eisai is committed to implementing access programs to ensure that its products reach patients around the world and the overall improvement of healthcare systems.

Eisai also strives to conduct activities that address the specific needs of female cancer patients and seek out collaborations with medical institutions to provide training programs for oncology care management specialists. By helping to build community care networks that provide a seamless range of services from point of diagnosis through treatment, including home care, palliative care and end-of-life care, the company aims to further its commitment to improving the quality of life of cancer patients and their families and creating communities that are supportive of people living with the disease.