Repeated dosing of radiopharmaceutical found safe, effective in PCa patients with bone mets

Repeated doses of the targeted radiopharmaceutical samarium Sm-153 lexidronam injection (Quadramet) are a safe and effective treatment option in patients with painful bone metastases secondary to prostate cancer, according to a multicenter, phase IV study published recently in the online edition of Cancer.

“Effective pain management improves a patient’s quality of life throughout all stages of disease. The results of this study clearly indicate that repeated dosing of Quadramet is efficacious, well tolerated, and a reasonable treatment option for patients with relapsed bone pain,” said lead author A. Oliver Sartor, MD, of the Dana-Farber Cancer Institute in Boston.

In the study, which was conducted at 22 institutions in the United States, Canada, and Europe, the 55 patients who were administered multiple doses received a total of 135 administrations of samarium Sm-153 lexidronam (mean, 2.4 doses/patient; range, 2-11). The majority of patients had bone metastases secondary to prostate or breast cancer and had received numerous previous treatments.

Consistent decreases in pain scores using the Brief Pain Inventory were observed following each of the first three doses of samarium Sm-153 lexidronam. On an individual patient basis, at week 4, pain scores significantly decreased from baseline in 70%, 63%, and 80% of patients following doses one, two, and three, respectively (p<.001). The percentage of patients reporting a decrease in pain scores following each of the first three doses was similar to the percentage reported as responders in prior placebo-controlled (65% to 72%) and dose-controlled (70%) studies.

Adverse events included mild, transient suppression of platelets and white blood cells after treatment.