Epizyme’s Soft Tissue Cancer Drug Granted Speedy FDA Approval

Xconomy Boston — 

Epizyme won accelerated FDA approval Thursday for a drug developed to treat the rare cancer epithelioid sarcoma (ES).

The regulatory decision for the Epizyme (NASDAQ: EPZM) drug, tazemetostat (Tazverik), covers patients 16 or older whose ES has advanced or spread and is not eligible for surgical treatment. The drug is now the first FDA-approved treatment for this type of cancer, laying the groundwork for potential applications of the therapy in other cancers.

Cambridge, MA-based Epizyme set a $15,500 per month wholesale price for tazemetostat, before any discounts or rebates. The company aims to make the drug available within the next 10 days.

ES is a soft tissue cancer that develops under the skin, starting as a small but firm lump. It’s typically diagnosed in adults between 20 and 40 and often becomes fatal. ES patients often receive chemotherapy, though the company says that ES usually resists such treatment. Epizyme estimates that 800 people in the US have this type of cancer, 300 of whom are eligible for treatment with tazemetostat under the guidelines specified by the FDA approval.

Tazemetostat is a small molecule drug developed to block EZH2, an enzyme that plays a role in the development and progression of cancer. The FDA based its decision on the results of an open-label, single-arm clinical trial that tested the drug in 62 patients. In that Phase 2 study, the overall response rate to the twice-daily pill was 15 percent. The complete response rate, meaning a disappearance of all signs of the cancer, was 1.6 percent. The partial response rate was 13 percent. The drug’s effects lasted six months or longer in 67 percent of the patients who showed a response to the drug.

Serious side effects reported from the study included bleeding, fluid in the lungs, skin infections, and difficulty breathing. The most common side effects were pain, fatigue, nausea, decreased appetite, vomiting, and constipation.

Last month, an FDA advisory panel unanimously recommended approval of tazemetostat in ES. The FDA decision for the drug is an accelerated approval—a faster regulatory review using less evidence than is typically required. That means Epizyme will need to conduct additional studies to confirm the drug’s benefit to patients. Speaking on a conference call Thursday, CEO Rob Bazemore said that this confirmatory study will enroll 150 ES patients from across the world.

With approval of tazemetostat in hand for ES, Epizyme is now also planning possible commercialization of the drug in follicular lymphoma, a cancer of white blood cells called lymphocytes. In December, the company filed for accelerated FDA approval of the drug in that type of cancer.

“We’ve always viewed [approval in ES] as a way to get into the market and prepare for the follicular lymphoma launch,” Bazemore said.

The company also plans to seek regulatory approval of tazemetostat in Europe, but Bazemore said that ES probably will not be the first cancer it targets in that market. Discussion with European regulators is focusing on follicular lymphoma first.

Image of soft tissue sarcoma by the National Cancer Institute