FDA Agrees to Priority Review of Epithelial Sarcoma Drug Candidate Tazemetostat

According to a publication from Specialty Pharma Times, the American Food and Drug Administration (FDA) has granted priority review to Tazemetostat, Epizyme, Inc’s epithelioid sarcoma drug candidate.

About Epithelioid Sarcoma

Sarcoma are cancers that begin in connective tissue (like tendons, ligaments), bones, or other tissue. They are highly diverse, with over 70 different recognized types.

Epithelioid sarcoma is one such type. It is most common in young adults, and in most cases (60%) it affects the upper extremities. Epithelioid sarcomas are slow-progressing, and commonly begin in the soft tissue of a finger, hand, or forearm. Typically, these cancers are first observed as a small firm bump. Sometimes they may appear as non-healing ulcers. Over time, these bumps or ulcers may spread or grow if untreated. Biopsy and imaging may be required to confirm a diagnosis.

Treatments for epithelioid sarcoma are similar to those for other cancers, like surgery, chemotherapy, or radiation therapy. Because epithelioid sarcoma has a comparatively high risk of metastasizing (occurring in about 45% of patients), it is of particular concern to clinicians to diagnose and treat the sarcoma early and accurately.

Large-cell (proximal) epithelioid sarcoma is a more aggressive form of the condition that most typically affects older adults.

About Tazemetostat

The FDA has accepted Epizyme’s priority review request in their New Drug Application (NDA) for Tazemetostat. Priority review can circumstantially granted to any new drug application the FDA deems suitable, though manufacturers can also request the designation when filing the NDA.

The New Drug Application is the final hurdle of a drug’s “experimental” life — FDA approval of an NDA allows the manufacturer to bring their product to market. It can be thought of as the finish line for clinical research of a drug candidate. The FDA has set a Prescription Drug User Fee Act target date of January 23, 2020. This date is the point by which the FDA will deliver a ruling on the NDA.

Epizyme submitted the NDA in response to terrific results garnered by its phase 2 clinical study of Tazemetostat in 62 epithelioid sarcoma patients. The study yielded a 15% objective response rate and a 26% disease control rate, though the accuracy of “disease control rate” in phase 2 trials has been criticized — providing “…ambiguous information that likely exaggerates the anticancer activity of the therapy,” according to a 2011 publication.


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