Tazemetostat as a treatment for epithelioid sarcoma

Introduction: Epithelioid Sarcomas is a rare aggressive subtype of soft tissue sarcomas that is most prevalent in young adult males. It is locally invasive and frequently metastasizes to regional lymph nodes and distant organ sites. Complete surgical resection is curative in early-stage disease; however, there remains a high recurrence rate and distant metastatic risk. Outcomes remain poor in patients that develop metastatic disease. These tumors are characterized by loss of INI-1/SMARCB1 expression, which opposes the enzymatic function of EZH2, a critical component of epigenetic regulation. Tazemetostat is a highly selective, orally available EZH2 inhibitor. The recommended dose of Tazemetostat is 800 mg twice daily for patients aged 16 years or older with advanced or metastatic epithelioid sarcomas not eligible for complete surgical resection. Areas covered: Clinical studies investigating Tazemetostat in epithelioid sarcomas. Expert opinion: Approval of the Tazemetostat New Drug Application represents the first FDA approval for the treatment of advanced epithelioid sarcomas. It is the first epigenetic therapy approved for solid tumors. The approval encourages investigation in epigenetic regulation as a targetable therapy in other tumor types. Clinical issues remaining post-approval include efficacy of Tazemetostat in combination with other approved agents, and follow up to assess the long-term safety risks.