This study involves taking a study drug called lurbinectedin. The overall goal of this study is to see if different doses of lurbinectedin are safe and effective at treating children and young adults with recurrent or relapsed solid tumors, including Ewing Sarcoma.

This study involves taking a study drug called lurbinectedin. The overall goal of this study is to see if different doses of the study drug are safe and effective at treating children and young adults with recurrent or relapsed solid tumors, including Ewing sarcoma.