On January 23, 2020, the Food and Drug Administration granted accelerated approval to tazemetostat (TAZVERIK, Epizyme, Inc.) for adults and pediatric patients aged 16 years and older with metastatic or locally advanced epithelioid sarcoma not eligible for complete resection.
Efficacy was investigated in a single-arm cohort (Cohort 5) of a multi-center trial (Study EZH-202, NCT02601950) in patients with histologically confirmed, metastatic or locally advanced epithelioid sarcoma. Patients were required to have INI1 loss, detected using local tests, and an Eastern Cooperative Oncology Group performance status of 0-2. Patients received tazemetostat 800 mg orally twice daily until disease progression or unacceptable toxicity. The major efficacy outcome measures were confirmed overall response rate (ORR) according to RECIST v1.1 (assessed by blinded independent central review) and duration of response.
The ORR for the 62 patients in Cohort 5 was 15% (95% CI: 7%, 26%), with 1.6% having complete responses and 13% partial responses; 67% of those responding had responses lasting 6 months or longer.
The most common adverse reactions (incidence ≥20%) were pain, fatigue. nausea, decreased appetite, vomiting and constipation.
The recommended tazemetostat dose is 800 mg taken orally twice daily with or without food.
This indication is approved under accelerated approval based on overall response rate and duration of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial. FDA granted tazemetostat orphan drug designation. A description of FDA expedited programs is in the Guidance for Industry: Expedited Programs for Serious Conditions-Drugs and Biologics.
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