Epizyme achieves POC milestone in EPZ-5676 DOT1L inhibitor clinical program

Epizyme, Inc. (NASDAQ: EPZM), a clinical stage biopharmaceutical company creating innovative personalized therapeutics for patients with genetically defined cancers, today announced the achievement of the proof of concept (POC) milestone in the EPZ-5676 DOT1L inhibitor clinical program, earning a $25 million payment under the company's collaboration with Celgene Corporation. The milestone was triggered by objective responses in patients with translocations of the MLL gene (MLL-r). These patients are currently enrolled in the fourth dose cohort in the dose escalation stage of the ongoing Phase 1 clinical study and are receiving uninterrupted treatment with EPZ-5676. 

Epizyme also announced today that a development candidate milestone has been achieved for one of the three histone methyltransferase (HMT) targets included in the company's collaboration with GlaxoSmithKline (GSK), earning a $4 million payment.

"2013 was a year of important accomplishments for Epizyme," said Robert Gould, Ph.D., chief executive officer, Epizyme. "We have achieved the proof of concept milestone for EPZ-5676, our first-in-class DOT1L inhibitor, in our Celgene collaboration, initiated an ongoing Phase 1 study of EPZ-6438, our first-in-class EZH2 inhibitor, in our Eisai collaboration, achieved a Development Candidate milestone in our GSK collaboration, and continue to advance our pipeline of personalized therapeutics for patients with genetically defined cancers."

"We are very pleased with EPZ-5676's emerging clinical profile and progress as a potential personalized therapeutic for patients with genetically defined acute leukemias," said Dr. Gould. "We look forward to presenting the data from our ongoing Phase 1 study of EPZ-5676, including the dose escalation stage that has completed enrollment and the adult MLL-r expansion stage that is now enrolling patients, at a medical conference in 2014."

Additionally, the European Medicines Agency's Committee for Orphan Medicinal Products recommended orphan drug designation for EPZ-5676 to the European Commission in December 2013. EPZ-5676 was granted orphan drug designation by the U.S. Food and Drug Administration in May 2013.

Including the Celgene POC milestone and the GSK development candidate milestone, Epizyme estimates a 2013 end-of-year cash and account receivables position of approximately $145 million versus previous guidance of an end-of-year cash position of more than $115 million.

Epizyme plans to have as many as five clinical proof of concept programs ongoing in 2014. For EPZ-5676, Epizyme's first-in-class DOT1L inhibitor, these include the ongoing adult MLL-r expansion stage, MLL-r in pediatric patients, and adult MLL-PTD patients. For EPZ-6438, Epizyme's first-in-class EZH2 inhibitor, these include adult non-Hodgkin lymphoma patients and also pediatric and young adult patients with synovial sarcomas, pending completion of the ongoing Phase 1 study.