Eisai Co., Ltd. (Headquarters: Tokyo, CEO: Haruo Naito, “Eisai”) announced today that Eisai and Epizyme, Inc. (Headquarters: Cambridge, Massachusetts, CEO: Robert Gould, Ph.D., “Epizyme”) have agreed to change the scope of collaboration for their worldwide partnership initiated in March 2011 to discover, develop and commercialize cancer therapeutics targeting EZH2, an epigenetic enzyme.

In March 2011, Eisai and Epizyme entered into a collaboration agreement concerning the discovery, development and commercialization of cancer therapeutics targeting the epigenetic enzyme EZH2 for the treatment of non-Hodgkin B-cell lymphoma and other cancers. Under this agreement, Eisai has been conducting a Phase Ⅰ/Ⅱ clinical study of the EZH2 inhibitor E7438 (Epizyme development code: EPZ-6438) in patients with advanced solid tumors or non-Hodgkin B-cell lymphoma.

Eisai and Epizyme have revised the scope of their partnership for worldwide development and commercialization rights for anticancer therapies targeting EZH2, including E7438, with Epizyme assuming responsibility for development and commercialization in regions outside of Japan and Eisai retaining responsibility for development and commercialization within Japan as well as having the right of first negotiation for licensing rights in Asia. The decision to change the scope of the partnership was agreed upon by the two companies in consideration of the priorities of each company's pipeline strategy and the maximization of the potential value of the compounds including E7438.

Based on this change in the agreement, Eisai will receive from Epizyme a contractual one-time payment as well as milestone payments as projects progress and marketing authorization is obtained. The companies will pay royalties to one another dependent upon on the sales in each company's respective sales regions after launch.

Eisai considers oncology a therapeutic area of focus and is committed to the development of new anticancer agents and treatments for supportive care. Eisai strives to further contribute to addressing the diverse needs of, and increasing the benefits provided to, patients with cancer and their families.

Media Inquiries:

Public Relations Department,
Eisai Co., Ltd.


< Notes to editors >

1. About Epizyme, Inc.

Epizyme, Inc. is a clinical stage biopharmaceutical company creating novel epigenetic therapeutics for cancer patients. Epizyme has built a proprietary product platform that the company uses to create small molecule inhibitors of a 96-member class of enzymes known as histone methyltransferases, or HMTs. HMTs are part of the system of gene regulation, referred to as epigenetics, that controls gene expression. Genetic alterations can result in changes to the activity of HMTs, making them oncogenic (cancer-causing). By focusing on the genetic drivers of cancers, Epizyme's targeted science seeks to match the right medicines with the right patients.
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2. About EZH2 and E7438

EZH2 is one of the proteins that make up the histone methyltransferases (HMTs) that alter gene expression. EZH2 is known to methylate lysine 27 of the protein H3 (H3K27), H3 being one of the five major histone groups (H1, H2A, H2B, H3 and H4) that together help to store DNA in eukaryotic cell nuclei. H3K27 methylation is also known to suppress gene transcription. It is believed that EZH2 regulates cell proliferation, and may have an important role in carcinogenesis. Also, deletion of the INI1 subunit SWI/SNF chromatin-remodeling complex occurs in nearly all malignant rhabdoid tumors (MRT), a rare cancer, but with a particularly poor prognosis. An antagonistic relationship has been demonstrated between the biochemical action of the SWI/SNF complex and EZH2 on chromatin, which is relieved in MRT due to the INI1 deletion. EZH2 may be a potential driving oncogene in these cancers and therefore an important therapeutic target requiring further investigation. Created through Epizyme's proprietary product platform, E7438 (EPZ-6438) is a first-in-class selective small molecule inhibitor of the epigenetic enzyme EZH2.