Targeting Pediatric Brain Tumors and Relapsed/Refractory Solid Tumors With Sodium Glucose Cotransporter 2 Inhibitors (SGLT2i)

This study is testing a drug called sodium iodide symporter (NIS)-based gene therapy in children and young adults with hard-to-treat brain tumors or solid tumors that have come back and have no other curative options. **You may be eligible if...** - You are 6–21 years old - You have a recurrent brain tumor with no curative treatment available, OR a relapsed/refractory solid tumor (such as sarcoma, neuroblastoma, or Wilms tumor) that has failed at least two lines of therapy - You have measurable disease on imaging - You can swallow whole pills - Your life expectancy is more than 12 weeks - Your blood counts and organ function are within acceptable ranges - Your oxygen levels are normal at room air **You may NOT be eligible if...** - You are under 6 or over 21 years old - You cannot swallow pills - Your blood counts or organ function are significantly impaired - Your oxygen saturation is below 97% and your breathing capacity is below 80% Talk to your doctor to see if this trial is right for you.