What You Need to Know About the FDA's Approval of Tazverik For Epithelioid Sarcoma

Recently, the Food and Drug Administration (FDA) granted accelerated approval to Tazverik (tazemetostat) for the treatment of adults and pediatric patients, 16 years or older, with metastatic or locally advanced epithelioid sarcoma who are not eligible for complete resection (the surgical removal of the tissue).

The FDA’s Oncologic Drugs Advisory Board voted unanimously to approve Tazverik, marking the first approved treatment specifically for patients with epithelioid sarcoma — a rare soft tissue cancer and subtype of soft tissue sarcoma.

“Tazverik is now the first and only FDA-approved EZH2 inhibitor, and the first and only FDA-approved treatment specifically indicated for (epithelioid sarcoma) patients,” stated Robert Bazemore, president and chief executive officer of Epizyme, the biopharmaceutical company behind Tazverik, in the initial approval press release last week. “Our commercial launch plans are underway, and we expect to make Tazverik available to patients (with epithelioid sarcoma) and treating physicians across the US within 10 business days.”

The fast track approval was granted based on the findings of a single-arm cohort of a multicenter phase 2 study of patients with metastatic or locally advanced epithelioid sarcoma. The FDA based the approval on the overall response rate and duration of response found in this study, citing that these benefits outweighed the risks of the treatment as it addressed an unmet need for a rare disease with no other specific treatments.

The study had a 15% overall response rate among the 62 patients treated: 1.6% of those patients achieved a complete response and 13% had a partial response. Sixty-seven percent of the patients treated with Tazverik had a duration of response for six months or longer.

However, 37% of patients experienced serious side effects such as hemorrhage, pleural effusion, skin infection, dyspnea, pain, and respiratory distress. The most common side effects of the treatment were pain, fatigue, nausea, decreased appetite, vomiting and constipation.

“I think when you look at sarcoma in general, and then especially epithelioid sarcoma, it's really been left behind,” explained Brandi Felser, the executive director of the Sarcoma Foundation of America, in an interview with CURE. “…There wasn't any hope for them, because there wasn't a treatment specifically for epithelioid sarcoma. And not because it's such a rare cancer, there was not a lot of investment in new treatments, because there were so few patients. What this (approval) does is it shows that a company can invest in these patients.”

Felser cited a lack of education and awareness in general that has kept patients with epithelioid sarcoma without a treatment for so long. Now, that is changing, and when patients with epithelioid sarcoma are diagnosed and find a sarcoma specialist, they have a treatment waiting for them, and she hopes that access to a sarcoma specialist becomes easier for patients.

“It provides patients with some relief, and a sense of hope, when previously there was nothing at all for this disease,” she said. “And now, they were hopeless before and now at least they have something, but remember, there's over 50 more subtypes of sarcoma that still don't have treatments,” Felser added, “We've continued to be left behind. So, there's still a need for research and investments in these rare cancers.”

Read CURE’s original coverage of Tazverik’s approval.