Cytogen Corporation’s study of Quadramet (samarium Sm-153 lexidronam injection), the company's flagship product, in combination with gemcitabine (Gemzar, Eli Lilly), a nucleoside analog which is known to be a radiation sensitiser demonstrated an improvement of the majority of patients with advanced stage disease who were treated with the combination regimen.

According to a company release, the study was conducted by independent investigators who evaluated the use of high dose Quadramet in conjunction with gemcitabine for the treatment of osteosarcoma.

“Quadramet is the most specific agent currently available for targeting osteoblastic metastases of osteosarcoma. 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 radiosensitising 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. Planned future directions using Quadramet in osteosarcoma will include repeated standard doses in combination with gemcitabine in an attempt to increase the durability of the clinical response," said Dr Anderson.

In the study, routine radionuclide bone and positron emission tomography (PET) imaging studies were used to assess response to therapy. In this very heavily pre-treated group of patients, no hemorrhagic cystitis, nephrotoxicity, or serious infections were reported and successful re-engraftment occurred in all patients. The treatment group had variable performance status before treatment. After treatment, all patients maintained stable or improved performance status except the single patient with poor initial performance status, informs a company release.

Osteogenic sarcoma, or osteosarcoma, is the most common primary malignancy of the bone in the United States. Osteosarcoma is slightly more common in males than in females.