This is a dose escalation study of a new radiopharmaceutical agent, 153Sm-DOTMP. Eligible participants will have osteosarcoma metastatic to bone, other solid tumors with bone metastases, or an unresectable localized osteosarcoma. Because of anticipated prolonged myelosuppression, participants will have a peripheral blood stem cell harvest. They will then be treated with 2 doses of 153Sm-DOTMP given 7 days apart. Twenty-four days after the initial dose, stem cells will be reinfused if needed. The first three cohorts of participants will receive only radiopharmaceutical. If Dose Level 3 is not the maximally tolerated dose (MTD), subsequent dose levels will include external beam radiotherapy, administered beginning on Day 15. The dose of external beam radiotherapy will be determined by dosimetry studies performed after each administration of study agent, and will be targeted to a tumoricidal dose of radiation. All participants will have disease re-evaluation 30 days following completion of all study treatments, and then at 4, 6, 8, and 12 months, unless they experience disease progression.
This is a dose finding study of a novel radiopharmaceutical agent, 153Sm-DOTMP. It will be studied alone and then in combination with external beam radiotherapy. The study design includes six cohorts, Levels 1-6. The first three cohorts of participants will receive 153Sm-DOTMP alone, and if this is determined to be safe, subsequent cohorts will receive the radiopharmaceutical followed by external beam radiotherapy.