This study involves taking a study drug called INBRX-109. The overall goal of the study is to find out how safe and effective the study drug is in treating people that have been diagnosed with advanced or metastatic Ewing sarcoma or SDH-deficient solid tumor/Gastrointestinal Stromal Tumor (GIST).

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 enrolls patients with refractory, progressive, or relapsed solid tumors. The purpose of this study is to find out whether a drug called PEEL-224 ("the study drug") is safe and effective when given as monotherapy (a drug given by itself) and as part of a combination therapy together with other chemotherapy drugs.

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.