Safety and efficacy parameters in patients treated with TiN-117m DTPA

We determined factors related to the administered dose versus efficacy and hematological toxicity in patients treated with Sn-117m DTPA for palliation of metastatic bone pain. We collected data in 47 patients (50 administrations) given Sn-117m DTPA in a dose escalation trial (5, 10, 12.5, 16, and 20 mCi/70/kg) for alleviation of pain from bone metastases derived from a variety of primary cancers. We correlated administered activity per unit body weight and calculated marrow dose, with both percent and absolute decrease in WBC and platelet counts, percent pain response, and onset of pain relief. We also correlated pain response with the extent of disease, using degree of uptake of tracer in bone and the bone index. At 5-20 mCi/70 kg dose levels, Sn-117m appears to have less hematological toxicity than other bone pain palliation agents (p<0.05). Overall pain relief (75%) was not correlated with administered activity and is similar to the other agents. There was a good correlation (p<0.05) between low and high levels of administered dose with response onset.