Epizyme Enrolls First Patient in Phase 1/2 Clinical Trial of EPZ-6438, an Inhibitor of EZH2

  Epizyme Enrolls First Patient in Phase 1/2 Clinical Trial of EPZ-6438, an
                              Inhibitor of EZH2

Company Earns $6 Million Milestone Payment from Eisai for Trial Initiation

PR Newswire

CAMBRIDGE, Mass., June 13, 2013

CAMBRIDGE, Mass., June 13, 2013 /PRNewswire/ --Epizyme, Inc., (NASDAQ: EPZM)
a clinical stage biopharmaceutical company creating innovative personalized
therapeutics for patients with genetically defined cancers, announced today
that the first patient has been enrolled in a Phase 1/2 clinical trial of
EPZ-6438 (E7438). The trial is designed to assess the safety, tolerability and
pharmacokinetics of EPZ-6438 (E7438), an orally available, small molecule
inhibitor for non-Hodgkin lymphoma patients who have a cancer-causing
(oncogenic) point mutation in EZH2.

Epizyme is developing EPZ-6438 (E7438) in partnership with Eisai Co., Ltd. In
April 2011, the two companies announced a worldwide partnership to discover,
develop and commercialize therapeutics targeting EZH2, with Epizyme retaining
an opt-in right to co-develop, co-commercialize and share profits with Eisai
on licensed products in the United States. As a result of the first patient
enrollment in this trial, Epizyme earned a $6 million milestone payment from
Eisai.

About EZH2 Cancers

EZH2 is a histone methyltransferase (HMT) that can become oncogenic and cause
non-Hodgkin lymphoma and solid tumors. Two types of non-Hodgkin lymphoma,
diffuse large B-cell lymphoma of germinal-center origin, or DLBCL, and
follicular lymphoma, or FL, are mainly associated with oncogenic EZH2
mutations. Currently, there are no therapies approved specifically for the
treatment of non-Hodgkin lymphoma associated with an EZH2 point mutation.

About Epizyme, Inc.

Epizyme is a clinical stage biopharmaceutical company creating personalized
therapeutics for patients with genetically defined cancers. 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).

For more information, visit http://www.epizyme.com and connect with us on
Twitter at @EpizymeRx.

SOURCE Epizyme, Inc.

Website: http://www.epizyme.com