Dr. Chi on Study of Tazemetostat in Children With INI1-Negative Tumors

Susan N. Chi, MD, senior physician, director, Pediatric Brain Tumor Clinical Trials Program, Dana-Farber Cancer Institute, assistant professor of pediatrics, Harvard Medical School, discusses a phase I multicenter trial of tazemetostat in children with INI1-negative tumors.

Investigators are evaluating the EZH2 inhibitor tazemetostat in children with relapsed or refractory INI1-negative tumors including rhabdoid tumors, epithelioid sarcoma, chordoma, and synovial sarcoma. The use of tazemetostat in this population makes sense, explains Chi, as EZH2 is one unit in a multi-unit complex called polycomb repressive complex 2 (PRC2). PRC2 works antagonistically to the SWI/SNF complex, of which INI1 is a member.

This is the first time that tazemetostat has been used in children, and the first time that EZH2 has been tested in children. In the phase I trial, tazemetostat was dosed continuously as an oral suspension administered twice daily in patients aged 6 months to 21 years. Chi says that this has been a collaborative effort, and the study is now moving into a dose-expansion phase based on positive safety signals in the phase I trial.