Epizyme, a clinical-stage biopharmaceutical company creating novel epigenetic therapies, has announced advancements in the company’s clinical programs evaluating tazemetostat, its first-in-class EZH2 inhibitor. The FDA has granted tazemetostat Fast Track designation in patients with diffuse large B-cell lymphoma (DLBCL) with EZH2 activating mutations. Additionally, Epizyme is focusing its phase II registration-enabling study in adult patients with genetically-defined solid tumors on those cancers marked by loss of INI1, and has expanded enrollment in the epithelioid sarcoma cohort of the study based on encouraging early activity in this patient population.

“We are very proud of the continued advancement of our tazemetostat clinical program in both non-Hodgkin lymphoma and genetically-defined solid tumors, important areas of unmet medical need for patients with cancer,” said Robert Bazemore, president and chief executive officer, Epizyme. “These developments reflect the execution of our strategy to identify the patient groups who may benefit most from tazemetostat, and our efforts to bring this investigational medicine to patients as quickly as possible.”

The FDA has granted Fast Track designation for the investigation of tazemetostat for the treatment of patients with relapsed or refractory DLBCL whose tumors carry an EZH2 activating mutation. Tazemetostat inhibits EZH2, a histone methyltransferase that is increasingly understood to play a role in the growth and proliferation of a number of cancers, including DLBCL, the most commonly diagnosed form of NHL.

The FDA Fast Track program is designed to facilitate the development of important new drugs and to provide patients access to those drugs more quickly. The designation enables early and frequent communication between FDA and a product sponsor throughout the drug development and review process. Through the Fast Track program, a product may be eligible for priority review at the time of a new drug application (NDA) filing and may also be eligible to submit completed sections of the NDA on a rolling basis before the complete application is submitted. These expedited processes can potentially reduce development time and cost associated with bringing a drug to market.

Following review by the Independent Data Monitoring Committee, Epizyme has expanded the epithelioid sarcoma cohort of its ongoing Phase 2 trial in adult patients with INI1-negative solid tumors. This expansion is based on encouraging early activity seen, including confirmed objective responses, in the cohort. The company plans to enroll an additional 30 patients with epithelioid sarcoma, bringing the cohort to a total of 60 patients. This study represents the largest trial conducted to date in this rare tumor type. Epithelioid sarcoma is a soft tissue sarcoma characterized by loss of INI1. There are currently no approved systemic therapies for the treatment of patients with epithelioid sarcoma, and outcomes are extremely poor.

The synovial sarcoma arm of the phase II trial has been fully enrolled. Although some patients remain on treatment, Epizyme has concluded that the activity of tazemetostat in this cohort is insufficient to continue further investigation of tazemetostat as a monotherapy. Unlike the cancers in the other four arms of the study, synovial sarcoma is characterized by a functional dysregulation of INI1, rather than by a complete loss of INI1.

Epizyme is now focusing its efforts on the four cohorts of INI1-negative tumors in its study, including the epithelioid sarcoma cohort. Enrollment continues in these cohorts and Epizyme plans to present data from the phase II trial in the first half of 2017.

“The early clinical activity observed in the epithelioid sarcoma arm provides encouraging evidence of the effectiveness of EZH2 inhibition with tazemetostat in patients with INI1-negative tumors,” added Peter Ho., M.D., Ph.D., chief medical officer, Epizyme. “The clinical experience observed so far in both the epithelioid sarcoma and synovial sarcoma cohorts is consistent with our phase I experience for these cancers. We look forward to assessing clinical activity in the phase II study and reporting data in the first half of 2017.”

Tazemetostat, a first-in-class EZH2 inhibitor, is being evaluated as a monotherapy and in combination with other agents in multiple cancer indications. Phase II studies of tazemetostat as a monotherapy are currently ongoing in patients with non-Hodgkin lymphoma; in adults with INI1-negative tumors and children with certain genetically defined solid tumors, including INI1-negative tumors and synovial sarcoma; and in patients with mesothelioma characterized by BAP1 loss-of-function.

Additionally, tazemetostat is being evaluated in two combination studies in patients with DLBCL. A phase Ib/II trial of tazemetostat in combination with R-CHOP, an immuno-chemotherapy regimen consisting of rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone, is being conducted as a front-line treatment for patients with DLBCL as part of Epizyme’s collaboration with the Lymphoma Study Association. A phase Ib study evaluating tazemetostat in combination with Tecentriq (atezolizumab), an anti-PD-L1 cancer immunotherapy approved by the FDA, is being conducted as part of a collaboration with Genentech, a member of the Roche Group, in relapsed and refractory patients with DLBCL.