FDA Approves First Treatment for Rare Soft Tissue Cancer

The U.S. Food and Drug Administration granted accelerated approval to Epizyme’s Tazverik for the treatment of adults and pediatric patients ages 16 years and older with metastatic or locally advanced epithelioid sarcoma not eligible for complete resection.

Epithelioid sarcoma is a rare sub-type of soft tissue sarcoma that often occurs in young adults and accounts for less than one percent of all soft tissue sarcomas. Most cases of epithelioid sarcoma begin in the soft tissue under the skin of an extremity, though it can start in other areas of the body. Surgical removal is considered the main treatment when the cancer is localized to one area of the body. However, there is a high likelihood for local and regional spread of the disease even with treatment and approximately 50 percent of patients have metastatic disease at the time of diagnosis with median overall survival of less than one year.

“Until today, there were no treatment options specifically for patients with epithelioid sarcoma,” said Richard Pazdur, director of the FDA’s Oncology Center of Excellence and acting director of the Office of Oncologic Diseases in the FDA’s Center for Drug Evaluation and Research. “The approval of Tazverik provides a treatment option that specifically targets this disease.”

Tazverik (tazemetostat) is a methyltransferase inhibitor that blocks activity of EZH2, which may help keep the cancer cells from growing. Tazverik’s approval was based on the results of a phase 2 clinical trial that enrolled 62 patients with metastatic or locally advanced epithelioid sarcoma. The trial measured how many patients experienced complete or partial shrinkage, by a certain amount, of their tumors during treatment. The overall response rate was 15 percent, with 1.6 percent of patients having a complete response and 13 percent having a partial response. Of the nine patients that had a response, six patients had a response lasting six months or longer.

One third of the study patients experienced serious adverse effects such as hemorrhage and skin infections and another third had to pause taking the drug due to side effects. However, Epizyme was able to show safety data from more than 600 people who have received the approved dose of the drug across other study cohorts and cancer types.

Although the overall response rate was modest, an FDA advisory committee unanimously agreed at a meeting in December that the drugs’ benefit outweighed its risks.

“For people with epithelioid sarcoma, an aggressive life threatening cancer that affects young adults, having new treatment options can offer much needed hope,” said Denise Reinke, president and CEO of the Sarcoma Alliance for Research through Collaboration and co-founder of the Sarcoma Coalition.

The approval of Tazverik is contingent upon verification of clinical benefit in a confirmatory trial, which has just gotten underway. That trial will assess the combination of Tazverik plus doxorubicin compared with doxorubicin plus placebo as a front-line treatment for epithelioid sarcoma.

Epizyme also agreed to expand enrollment in another cohort of its phase 2 trial and plans to conduct several post-marketing evaluations.

Epizyme said it will make Tazverik available within the next ten days and is pricing it at $15,500 per month, a price similar to that of recently approved cancer drugs.

The approval of Tazverik is a first for Epizyme, coming five years after it bought back the rights for the drug from the Japanese pharmaceutical Eisai. The company is also aiming to win a second approval in the larger indication of follicular lymphoma for which it submitted an application for approval in December.

Photo: Denise Reinke, president and CEO of the Sarcoma Alliance for Research through Collaboration and co-founder of the Sarcoma Coalition

Author: Rare Daily Staff