Epizyme Doses First Patient In Five-Arm Phase 2 Study For First-In-Class EZH2 Inhibitor Tazemetostat (EPZ-6438) In Relapsed Or Refractory Non-Hodgkin Lymphoma

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Epizyme, Inc. (NASDAQ: EPZM), a clinical stage biopharmaceutical company creating novel epigenetic therapies for cancer patients, announced today that it has dosed the first patient in the phase 2 trial of its lead clinical candidate, tazemetostat (EPZ-6438) in patients with relapsed or refractory non-Hodgkin lymphoma (NHL). This five-arm study will enroll up to 150 patients with germinal center diffuse large B cell lymphoma (DLBCL) or follicular lymphoma, stratified into those expressing mutant EZH2 and those expressing wild type EZH2, as well as patients with non-germinal center DLBCL.

“Results from our ongoing phase 1 trial that we presented at the International Congress on Malignant Lymphoma on June 20 show tazemetostat produced durable objective responses in heavily pre-treated patients with relapsed or refractory NHL, with an acceptable safety and tolerability profile”

“Results from our ongoing phase 1 trial that we presented at the International Congress on Malignant Lymphoma on June 20 show tazemetostat produced durable objective responses in heavily pre-treated patients with relapsed or refractory NHL, with an acceptable safety and tolerability profile,” said Peter Ho, M.D., Ph.D., Chief Development Officer, Epizyme. “With the initiation of this phase 2 trial, we look forward to making significant progress in evaluating the potential of tazemetostat in targeted sub-populations of NHL.”

About the Tazemetostat Phase 2 Program
The phase 2 NHL trial is a five-arm, multi-center, international study that will assess the safety and activity of tazemetostat in patients with relapsed or refractory non-Hodgkin lymphoma. The study will enroll up to 30 patients in each arm, prospectively stratified for EZH2 mutation status and cell-of-origin, assuming each arm of the study achieves its primary response rate goal in its first stage. The five study arms are enrolling relapsed/refractory patients with:

• Germinal center DLBCL with mutant EZH2
• Germinal center DLBCL with wild-type EZH2
• Follicular lymphoma with mutant EZH2
• Follicular lymphoma with wild-type EZH2
• Non-germinal center DLBCL

A second planned phase 2 trial of tazemetostat in adult patients with INI1-deficient solid tumors is expected to initiate later in 2015. A phase 1 study in pediatric patients with INI1-deficient solid tumors is also expected to start later in 2015.

The Company also plans to initiate additional clinical evaluations of tazemetostat, including a combination with R-CHOP in patients with DLBCL, and a combination with a B-cell signaling agent or other emerging targeted therapies for B-cell lymphomas.

About EZH2 in Cancer
EZH2 is a histone methyltransferase (HMT) that is increasingly understood to play a potentially oncogenic role in a number of cancers. These include non-Hodgkin lymphomas, INI1-deficient cancers such as malignant rhabdoid tumors, epithelioid sarcomas and synovial sarcoma; and a range of other solid tumors.

About Tazemetostat
Epizyme is developing tazemetostat for the treatment of non-Hodgkin lymphoma patients and patients with INI1-deficient solid tumors. Tazemetostat is a first-in-class small molecule inhibitor of EZH2 created by Epizyme using its proprietary product platform. In many human cancers, aberrant EZH2 enzyme activity results in misregulation of genes that control cell proliferation resulting in the rapid and unconstrained growth of tumor cells. Tazemetostat is the WHO International Non-Proprietary Name (INN) for compound EPZ-6438.

Tazemetostat is the second HMT inhibitor to enter human clinical development (following Epizyme's DOT1L inhibitor, pinometostat, also known as EPZ-5676). The phase 1 study of tazemetostat is ongoing, with additional data expected to be reported later in 2015.

Additional information about this program, including clinical trial information, may be found here: https://clinicaltrials.gov/ct2/show/NCT01897571

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.

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

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Any statements in this press release about future expectations, plans and prospects for Epizyme, Inc. and other statements containing the words "anticipate," "believe," "estimate," "expect," "intend," "may," "plan," "predict," "project," "target," "potential," "will," "would," "could," "should," "continue," and similar expressions, constitute forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by such forward-looking statements as a result of various important factors, including: uncertainties inherent in the initiation of future clinical studies or expansion of ongoing clinical studies; availability and timing of data from ongoing clinical studies; whether interim results from a clinical trial such as the results referred to in this release will be predictive of the final results of the trial or the results of future trials; expectations for regulatory approvals to conduct trials or to market products; development progress of the Company’s companion diagnostics, availability of funding sufficient for the Company’s foreseeable and unforeseeable operating expenses and capital expenditure requirements; other matters that could affect the availability or commercial potential of the Company’s therapeutic candidates or companion diagnostics; and other factors discussed in the "Risk Factors" section of the company’s Form 10-Q filed with the SEC on April 28, 2015, and in our other filings from time to time with the SEC. In addition, the forward-looking statements included in this press release represent the Company's views as of the date hereof. The Company anticipates that subsequent events and developments will cause the Company's views to change. However, while the Company may elect to update these forward-looking statements at some point in the future, the Company specifically disclaims any obligation to do so. These forward-looking statements should not be relied upon as representing the Company's views as of any date subsequent to the date hereof.