GPC2 CAR T Cells for Relapsed or Refractory Neuroblastoma and Metastatic Retinoblastoma

This study tests a new type of immune cell therapy (CAR T-cells targeting a protein called GPC2) in children and young adults with high-risk neuroblastoma or metastatic retinoblastoma — two rare and aggressive childhood cancers — that have come back or stopped responding to treatment. **You may be eligible if...** - You (or your child) are at least 1 year old with high-risk neuroblastoma that has relapsed or is refractory - OR you have metastatic retinoblastoma that has not responded to other treatments - Your tumor tests positive for the GPC2 protein **You may NOT be eligible if...** - The cancer does not express the GPC2 protein - You have active serious infections or significant organ problems - You have had certain prior cell or gene therapies Talk to your doctor to see if this trial is right for you.