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Ovarian CancerNovember 2020Summary reviewed July 2026

What Researchers Found Testing Tazemetostat for Epithelioid Sarcoma

Scientists tested tazemetostat in 62 people with advanced epithelioid sarcoma, a rare and aggressive soft-tissue cancer. About 15% of patients saw their tumors shrink, and the treatment was generally well tolerated with manageable side effects.

What the trial was testing

The trial enrolled 267 patients with ovarian cancer. The study was sponsored by Epizyme, Inc. and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was initial testing (phase 2). Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.

What the results showed

15% of patients with advanced epithelioid sarcoma had their tumors shrink with tazemetostat.

The Lancet. Oncology · 2020 · NCT02601950

These findings — that had their tumors shrink with tazemetostat treatment — were published in the The Lancet. Oncology and represent the headline result of the study.

Researchers tracked outcomes across 267 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.

What this means for patients

For patients with ovarian cancer, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.

What you can do now

Tazemetostat received FDA approval in January 2020 for advanced epithelioid sarcoma with loss of INI1 protein. This approval was based on this study. If you have this type of cancer, talk with your doctor about whether tazemetostat might be right for you, especially if other treatments haven't worked.

Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.