Radiotherapy for Osteosarcoma

A recent study demonstrated that a selective small molecule and radiation therapy called Quadramet can help osteosarcoma patients when used in combination with a radiosensitizing chemotherapeutic agent.

Osteosarcoma is more prevalent in children and there are currently few treatment options for patients with advanced stage bone cancer. Quadramet was shown to be effective in treating these patients and with lower toxicity than often associated with radiation treatment.

Quadramet (samarium Sm-153 lexidronam injection), developed by Cytogen Corp. (Princeton, NJ, USA), was used in the study in combination with gemcitabine (Gemza, Eli Lilly [Indianapolis, IN, USA]), a nucleoside analog that is known to be a radiation sensitizer. The majority of patients with advanced stage disease who were treated with the combination regimen demonstrated an improvement on imaging studies. The results of the study were published in the October 7, 2005, issue of the journal Clinical Cancer Research.

Quadramet pairs the targeting ability of a small molecule, bone-seeking phosphonate (EDTMP) with the therapeutic potential of radiation (samarium Sm-153). Skeletal invasion by prostate, breast, multiple myeloma, and other cancers frequently creates an imbalance between the normal process of bone destruction and formation. Quadramet selectively targets such sites of imbalance, thereby delivering radioactivity to regions of the skeleton that have been invaded by metastatic tumor.

"Our previous studies have demonstrated that a regimen consisting of high-dose Quadramet followed by stem cell transplant is well tolerated. These results indicate that a radiosensitizing chemotherapeutic can be added to such a regimen. The positive clinical responses observed in this study indicate that further evaluation of this combination strategy is warranted,” observed lead investigator Peter Anderson, M.D., Ph.D., a pediatric oncologist who performed the study at the Mayo Clinic (Rochester, MN, USA).




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