Epizyme Announces Updated Tazemetostat Phase 1 Data

(RTTNews) - Epizyme Inc. (EPZM) reported results from the ongoing phase 1 trial of tazemetostat, its first-in-class EZH2 inhibitor. The data showed that tazemetostat demonstrated clinical activity in a broader group of patients with INI1-negative and SMARCA4-negative tumors than previously reported, achieved inhibition of EZH2 in tumor tissue, and had an acceptable safety profile when administered as oral monotherapy in adult patients with relapsed or refractory INI1-negative and SMARCA4-negative tumors.

Based on tazemetostat's clinical activity observed to date and other supportive research, Epizyme will initiate a global phase 2 study in adults and a global phase 1 study in children with INI1-negative tumors and synovial sarcoma in the fourth quarter of 2015.

"INI1-negative tumors represent a group of devastating diseases with a very poor prognosis even for patients who can undergo a complete surgical resection. Tazemetostat has induced objective responses that are durable for some patients and has an excellent safety profile," said Dr. Italiano. "Our data provide evidence that potentially changes the landscape of clinical research in this group of tumors and could improve the treatment paradigm for these traditionally refractory diseases."

In total, 30 patients with solid tumors were enrolled into this ongoing phase 1 study, including eight patients in a food effect sub-study. Of these 30 patients, eight had INI1-negative tumors, comprised of five with malignant rhabdoid tumors and three with epithelioid sarcomas. Additionally, three patients had SMARCA4-negative tumors including two patients with malignant rhabdoid tumor of the ovary, also referred to as small cell carcinoma of the ovary hypercalcemic type, and one patient with thoracic sarcoma. Nineteen patients had other solid tumors that were not characterized by INI1 or SMARCA4 loss, including three patients with synovial sarcomas.

In addition to the 30 patients with solid tumors, 21 patients with advanced Non-Hodgkin Lymphoma were also enrolled into this ongoing phase 1 study, and the safety data from the ECC update presentation includes these patients.

"We are excited by these data, which show clinical activity in patients with INI1-negative and SMARCA4-negative tumors. These results are consistent with preclinical data that demonstrate the important role of EZH2 in INI1- and SMARCA4-negative tumors such as malignant rhabdoid tumors where median survival after relapse is approximately nine months," said Peter Ho, M.D., Ph.D., Chief Medical Officer, Epizyme. "We are now turning our attention to initiating global registration-supporting clinical trials in adults and children with these aggressive tumors, for which new treatments are needed."

EPZM closed the Friday's regular trading session at $17.89, down 8.77%.