FDA Grants Tazemetostat a Priority Review for Epithelioid Sarcoma

The Food and Drug Administration (FDA) granted a priority review for a new drug application (NDA) for tazemetostat to be used in epithelioid sarcoma (ES), according to Epizyme, the manufacturer of the drug.

ES is a rare and aggressive kind of soft tissue sarcoma that typically affects younger people by diminishing the INI1 protein. Average overall survival for patients with metastatic disease is typically less than 1 year, highlighting a crucial need for new developments for patients with ES.

The priority review for the first-in-class EZH2 inhibitor is proposed for treatment of patients with metastatic or locally advanced ES who are not eligible for curative surgery. Under the FDA’s Prescription Drug User Fee Act (PDUFA), the target action date is January 23, 2020.

“We are thrilled with FDA’s acceptance of this first tazemetostat NDA submission for priority review, and to be an important step closer to achieving our mission of rewriting treatment for patients with cancer and other serious diseases,” Robert Bazemore, president and chief executive officer of Epizyme, said in a statement.

The priority review was based off data from an ongoing phase II trial that was recently presented at the American Society of Clinical Oncology (ASCO) Annual Meeting that included patients with molecularly defined solid tumors.

Sixty-two patients were enrolled in the ES cohort of the trial—24 were treatment-naïve and 38 were relapsed/refractory. As of the September 17, 2018 cutoff date, findings show that tazemetostat treatment resulted in a 15% objective response rate (ORR) and a 26% disease control rate (DCR) for this patient population. At the time of the presentation, median duration of response (DOR) had not been reached.

Epizyme noted that they will launch a global confirmatory trial to support the full approval of their drug. They also plan to have a randomized, controlled clinical trial comparing tazemetostat in combination with doxorubicin versus placebo in the frontline setting. The primary endpoint will be progression-free survival (PFS), and secondary endpoints will include overall survival (OS), DCR, ORR, and DOR. The trial will have a safety run-in expected to start in the latter half of 2019.

“This is a significant achievement in the development of this potentially first-in-class EZH2 inhibitor, and we look forward to working with FDA during the review. If approved, we believe tazemetostat could become an important new option in the treating physicians’ arsenal. We would like to extend our sincerest gratitude to those patients, families, and medical teams who have participated in our clinical studies and helped bring tazemetostat to this stage,” Bazemore said.