This is a Phase I, open-label, dose escalation and dose expansion study with a BID oral dose
of tazemetostat. Subjects will be screened for eligibility within 14 days of the planned
first dose of tazemetostat. A treatment cycle will be 28 days. Response assessment will be
evaluated after 8 weeks of treatment and subsequently every 8 weeks while on study.
The study has two parts: Dose Escalation and Dose Expansion.
Dose escalation for subjects with the following relapsed/refractory malignancies:
Atypical teratoid rhabdoid tumor (ATRT)
Malignant rhabdoid tumor (MRT)
Rhabdoid tumor of kidney (RTK)
Selected tumors with rhabdoid features
Epithelioid malignant peripheral nerve sheath tumor
Extraskeletal myxoid chondrosarcoma
Renal medullary carcinoma
Other INI1-negative malignant tumors (e.g., dedifferentiated chordoma) (with Sponsor
Synovial Sarcoma with a SS18-SSX rearrangement
Dose Expansion at the MTD or the RP2D, for subjects with rhabdoid tumors
(MRT/ATRT/RTK/selected tumors with rhabdoid features).