Epizyme to Present Updated Data on Tazemetostat from Full Phase 2 Study Cohort in Epithelioid Sarcoma at ESMO

Epizyme, Inc. (Nasdaq: EPZM), a clinical-stage company developing novel epigenetic therapies, announced today that updated efficacy and safety data from the fully enrolled cohort of epithelioid sarcoma (ES) patients in its ongoing Phase 2 trial of tazemetostat will be presented in a poster discussion session at the European Society for Medical Oncology (ESMO) 2018 Congress to be held October 19-23 in Munich, Germany. Tazemetostat is the company’s potent, selective, orally available, first-in-class EZH2 inhibitor.

The Phase 2 study ES cohort completed enrollment in 2017 with a total of 62 patients. Detailed data will be presented at the Congress, including objective response rate (ORR), the study’s primary endpoint, and other important endpoints in this disease including duration of response, overall survival (OS), disease control rate and safety. For the first time, an analysis of ORR, durability and OS will be presented in both treatment-naive patients and in relapsed and/or refractory patients from the fully enrolled study cohort. Data will be presented by the study’s primary investigator, Mrinal Gounder, M.D., attending physician, Sarcoma Medical Oncology and Early Drug Development Service, and assistant professor, Memorial Sloan Kettering Cancer Center.

“We are excited to share these updated efficacy and safety data on tazemetostat in patients with epithelioid sarcoma, a rare and deadly cancer,” said Robert Bazemore, president and chief executive officer of Epizyme. “We remain committed to bringing this potential therapy to patients living with ES, and are confident as we progress towards our first NDA submission in the first half of 2019.”

In addition to the ES data, Epizyme will present data from the company’s Phase 2 study of tazemetostat in adult patients with INI1-negative tumors in two additional poster discussions and during one oral session at ESMO. A complete list of the tazemetostat presentations at ESMO are listed below:

Epithelioid Sarcoma Poster Discussion Session
Title: A phase 2, multicenter study of the EZH2 inhibitor tazemetostat in adults: (epithelioid sarcoma cohort)
Abstract No.: 1615PD
Date: Monday, October 22, 2018; 11:50 a.m. CEST
Location: Hall B3 - Room 23
Presenter: Mrinal Gounder, M.D.

Proffered Paper (Oral Presentation) Session
Title: Molecular characterization of epithelioid sarcoma (ES) tumors derived from patients enrolled in a phase 2 study of tazemetostat
Abstract No.: 1892O
Date: Saturday, October 20, 2018; 11:12 a.m. – 11:24 a.m. CEST
Location: Hall B3 - Room 21
Presenter: Mrinal Gounder, M.D.

Poster Discussion Sessions
Title: A phase 2, multicenter study of the EZH2 inhibitor tazemetostat in adults (INI1-negative tumors cohort)
Abstract No.: 1611PD
Date: Monday, October 22, 2018; 11:50 a.m. CEST
Location: Hall B3 - Room 23
Presenter: Silvia Stacchiotti, M.D.

Title: A phase 2, multicenter study of the EZH2 inhibitor tazemetostat in adults (rhabdoid tumor cohort)
Abstract No.: 1612PD
Date: Monday, October 22, 2018; 11:50 a.m. CEST
Location: Hall B3 - Room 23
Presenter: Robin L. Jones, MRCP, M.D.

Conference Call Information
Epizyme Management will host a conference call on Monday, October 22, 2018 at 8:30am EDT. To participate in the conference call, please dial 877-844-6886 (domestic) or 970-315-0315 (international) and refer to conference ID 8780088. The webcast can be accessed in the Investor Relations section of the company's website at www.epizyme.com. The replay of the webcast will be available in the investor section of the company’s website for 60 days.

About the Tazemetostat Clinical Trial Program
Tazemetostat, a potent, selective, orally available, first-in-class EZH2 inhibitor, is currently being studied as a monotherapy in ongoing Phase 2 programs in certain molecularly defined solid tumors, including epithelioid sarcoma and other INI1-negative tumors; follicular lymphoma (FL); and combination studies in diffuse large B-cell lymphoma (DLBCL) and non–small cell lung cancer (NSCLC).

About Epizyme, Inc.
Epizyme, Inc. is a clinical-stage biopharmaceutical company committed to rewriting treatment for cancer and other serious diseases through novel epigenetic medicines. Epizyme is broadly developing its lead product candidate, tazemetostat, a first-in-class EZH2 inhibitor, with studies underway in both solid tumors and hematological malignancies, as a monotherapy and combination therapy in relapsed and front-line disease. The company also is developing a novel G9a program with its next development candidate, EZM8266, which is targeting sickle cell disease. By focusing on the genetic drivers of disease, Epizyme's science seeks to match targeted medicines with the patients who need them. For more information, visit www.epizyme.com.

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 relating to the Company’s ability to resume enrollment in its tazemetostat trials and the timing of such resumption, and the impact of the safety finding on enrollment of patients in ongoing and future trials of tazemetostat following the lifting of the partial clinical hold and the resumption of enrollment; uncertainties inherent in the initiation of future clinical studies and in the availability and timing of data from ongoing clinical studies; whether interim results from a clinical trial will be predictive of the final results of the trial; whether results from preclinical studies or earlier clinical studies will be predictive of the results of future trials; whether results from clinical studies will warrant meetings with regulatory authorities, submissions for regulatory approval or review by governmental authorities under the accelerated approval process; whether Fast Track Designation and Orphan Drug Designations will provide the benefits for which tazemetostat is eligible; expectations for regulatory approvals to conduct trials or to market products; whether the company's cash resources will be sufficient to fund 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; and other factors discussed in the "Risk Factors" section of the company's most recent Form 10-Q filed with the SEC and in the company's 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 and should not be relied upon as representing the company's views as of any date subsequent to 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.

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Media:
Erin Graves, 617-500-0615
Epizyme, Inc.
[email protected]
or
Investors:
Monique Allaire, 617-895-9511
THRUST Strategic Communications
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