Epizyme Announces Tazemetostat Granted Orphan Drug Designation for Malignant Rhabdoid Tumors by U.S. FDA

- U.S. study sites enrolling adult patients with genetically-defined solid tumors, including malignant rhabdoid tumors, in registration-supporting phase 2 study

- U.S. study sites enrolling pediatric patients with genetically-defined solid tumors, including malignant rhabdoid tumors, in phase 1 dose escalation study

CAMBRIDGE, Mass.--()--Epizyme, Inc. (NASDAQ:EPZM), a clinical stage biopharmaceutical company creating novel epigenetic therapeutics for cancer patients, announced today that the United States Food and Drug Administration (FDA) has granted orphan drug status to the company’s first-in-class EZH2 inhibitor, tazemetostat, for the treatment of malignant rhabdoid tumors (MRTs). In December 2015, the company initiated a phase 2 study in adults and a phase 1 study in children with genetically defined tumors, including MRTs. Tazemetostat is also being investigated in an ongoing five-arm phase 2 study in patients with non-Hodgkin lymphoma.

“Malignant rhabdoid tumors are rare and aggressive cancers with poor outcomes. There have not yet been any targeted drugs developed specifically to treat these patients,” said Peter Ho, M.D., Ph.D., Chief Medical Officer, Epizyme. “In an ongoing phase 1 study, tazemetostat has demonstrated encouraging clinical activity and an acceptable safety profile in patients with these severe types of cancer. We believe tazemetostat has the potential to become an important targeted therapy for patients with MRT and we are working aggressively to execute our clinical development program.”

Orphan drug designation provides the sponsor of the drug with eligibility for various development incentives, including tax credits for qualified clinical testing and marketing exclusivity for a period of seven years. Therapies with orphan drug status are also not subject to a prescription drug user fee for the orphan indication.

Currently, treatment of MRT consists of surgery, chemotherapy and radiation therapy, which are associated with limited efficacy and significant treatment-related morbidity. MRT is a tumor defined by loss of INI1 protein as measured by immunohistochemistry. Other rhabdoid tumors, such as MRT of ovary, are characterized by loss of the protein SMARCA4 and have shown sensitivity to tazemetostat in preclinical models and in our phase 1 study. The orphan drug designation applies to both INI1-negative MRT as well as SMARCA4-negative MRT of ovary.

The ongoing phase 2 adult and phase 1 pediatric studies in patients with genetically-defined solid tumors include patients with rhabdoid tumors, other INI1-negative tumors, and synovial sarcoma. Interim data from Epizyme’s registration-supporting phase 2 clinical study of tazemetostat in adult patients with genetically defined solid tumors, including MRT, other INI1-negative tumors and synovial sarcoma, are anticipated to be presented at a medical conference in late 2016.

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 lymphoma, INI1-negative cancers such as malignant rhabdoid tumors and epithelioid sarcomas, certain SMARCA4-negative solid tumors, synovial sarcoma, and a range of other solid tumors.

About Tazemetostat

Epizyme is developing tazemetostat for the treatment of patients with non-Hodgkin lymphoma and for patients with INI1-negative solid tumors, certain SMARCA4-negative solid tumors and synovial sarcoma. Tazemetostat is a first-in-class small molecule inhibitor of EZH2 created by Epizyme using its proprietary product platform. In some human cancers, aberrant EZH2 enzyme activity results in dysregulation 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.

Additional information about this program, including clinical trial information for the adult 5-arm NHL study, can be found here: https://clinicaltrials.gov/ct2/show/NCT01897571

Clinical trial information for Epizyme’s ongoing phase 2 trial in adults and phase 1 trial in children with INI1-negative solid tumors, certain SMARCA4-negative solid tumors or synovial sarcoma can be found here:

https://clinicaltrials.gov/ct2/show/NCT02601950

https://clinicaltrials.gov/ct2/show/NCT02601937

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 chromatin modifying proteins (CMPs), such as histone methyltransferases or HMTs. CMPs 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 CMPs, 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.

Cautionary Note on Forward-Looking Statements

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; whether orphan drug designation will lead to orphan drug exclusivity or the other potential benefits of orphan drug designation for which we are eligible; 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" sections of the company’s Form 10-Q filed with the SEC on November 9, 2015 and recent prospectus supplement filed with the SEC on January 7, 2016, 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.

Contacts

Epizyme, Inc.
Andrew Singer, 617-500-0712
Executive Vice President and Chief Financial Officer
asinger@epizyme.com
or
Media/Investors:
THRUST Investor Relations
Monique Allaire, 617-895-9511
monique@thrustir.com

Contacts

Epizyme, Inc.
Andrew Singer, 617-500-0712
Executive Vice President and Chief Financial Officer
asinger@epizyme.com
or
Media/Investors:
THRUST Investor Relations
Monique Allaire, 617-895-9511
monique@thrustir.com