On December 7, 2019 Epizyme, Inc. (Nasdaq: EPZM), a late-stage biopharmaceutical company developing novel epigenetic therapies, reported positive, mature data at the 2019 American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting from its ongoing Phase 2 trial of tazemetostat, an oral EZH2 inhibitor, as a monotherapy for patients with follicular lymphoma (FL), both with or without EZH2 activating mutations, who have received at least two prior lines of systemic therapy (Press release, Epizyme, DEC 7, 2019, View Source [SID1234552056]).
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The data show that treatment with tazemetostat demonstrated meaningful clinical activity as assessed by both investigators and an Independent Review Committee (IRC), and was generally well tolerated in both FL patients with EZH2 activating mutations (n=45) and FL patients with wild-type EZH2 (n=54). The IRC assessment was conducted for inclusion in Epizyme’s planned NDA submission to the U.S. Food and Drug Administration (FDA) in December 2019.
As assessed by the IRC, as of an August 9, 2019 data cutoff date, tazemetostat treatment resulted in:
Objective response rate (ORR) of 69% for patients with an EZH2 mutation and 35% for patients with wild-type EZH2
Median duration of response of 11 months for patients with an EZH2 mutation and 13 months for patients with wild-type EZH2
Median progression-free survival of 14 months for patients with an EZH2 mutation and 11 months for patients with wild-type EZH2
Overall survival has not yet been reached for either FL patient population
"Follicular lymphoma remains an incurable disease today, and it’s essential that patients be able to receive treatment for an extended period of time," said Dr. Shefali Agarwal, chief medical officer of Epizyme. "We believe the clinically meaningful benefit of tazemetostat seen across both FL patient populations in this trial, along with its continued tolerability, are impressive findings. We are particularly pleased with the robust response rates, extended durability and consistency of data as assessed by investigators and independent reviewers. These data support tazemetostat’s potential to make a difference for FL patients, and we look forward to submitting our NDA for both patient populations later this month."
Follicular Lymphoma Phase 2 Cohort Design
Follicular lymphoma patients who had been previously treated with two or more systemic therapies were enrolled into two cohorts in the Phase 2 study. One cohort enrolled 45 patients with EZH2 activating mutations and a second enrolled 54 patients with wild-type EZH2. All patients were treated with 800 mg of tazemetostat, administered orally twice a day. The primary endpoint of the study is ORR, as assessed by the investigator, and defined as a complete response or partial response according to 2007 Cheson criteria. Secondary endpoints include duration of response, progression free survival, overall survival and safety.
Detailed Efficacy Results
The updated data were reported in an oral presentation entitled "Phase 2 Multicenter Study of Tazemetostat, an EZH2 Inhibitor, in Patients with Relapsed or Refractory Follicular Lymphoma" by Franck Morschhauser, M.D., Ph.D., Centre Hospitalier Régional Universitaire de Lille, France, an investigator in the Phase 2 trial. Efficacy data as assessed by both investigators and the IRC are summarized below:
1 Four patients not evaluable, or have missing or unknown data
2 Five patients not evaluable, or have missing or unknown data
3 Patient had stage 4 FL and received >2 prior lines of treatment
Safety Results
Favorable safety and tolerability have been observed with tazemetostat in these ongoing Phase 2 study cohorts. The most frequently reported treatment-related treatment-emergent adverse events (TEAEs) of Grade 3 or higher included thrombocytopenia (3%), anemia (2%), asthenia (1%) and fatigue (1%). TEAEs led to only 8% of patients discontinuing tazemetostat treatment and 9% of patients requiring a dose reduction. There were no treatment-related deaths while on study.
"We are thrilled to present these mature clinical data, which support our planned NDA submission for tazemetostat as a treatment for patients with follicular lymphoma," said Robert Bazemore, president and chief executive officer of Epizyme. "We have made tremendous progress in advancing our tazemetostat program, with multiple clinical and regulatory achievements this year. Our NDA for epithelioid sarcoma is under review, and we have finalized our commercial readiness plans in anticipation of an early 2020 launch. We have multiple clinical trials ongoing for tazemetostat in additional indications and combinations, and we are well underway with preparations to submit the FL NDA later this month. If approved, tazemetostat would be a first-in-class EZH2 inhibitor for patients with FL, representing an important new treatment with demonstrated efficacy, durability and safety."
About the Tazemetostat Clinical Trial Program
Tazemetostat, an oral, potent, first-in-class EZH2 inhibitor, is currently being studied as a monotherapy in ongoing clinical programs in patients with certain molecularly defined solid tumors, including epithelioid sarcoma and other INI1-negative tumors, and in patients with follicular lymphoma, both with and without EZH2 activating mutations. Multiple clinical studies are underway through collaborations assessing tazemetostat as a combination treatment for patients with diffuse large B-cell lymphoma. Epizyme is also conducting additional clinical trials designed to evaluate the potential benefit of tazemetostat in earlier lines of therapy for follicular lymphoma, as well as new combinations and cancer indications.