Trabectedin and Irinotecan may inhibit the activity of this Ewing sarcoma mutation. Trabectedin may suppress the proliferation of the gene involved in DNA damage response. It blocks EWS-FLI1 by inactivating the fusion protein and silences the target genes.
Irinotecan also suppresses the genes regulating the tumor cells, generating DNA damage. Together, these drugs work in combination to suppress the gene regulating the tumor cells. This combination may suppress the activity of the tumor regulating genes, disrupting the activity of the genes. The infusion of 18F-FLT in combination with a Positron Emission Tomography (PET) scan will demonstrate whether the target cells have been suppressed.