¹⁷⁷Lu-EDTMP for Treatment of Bone Pain in Patients with Disseminated Skeletal Metastases

Abstract

¹⁷⁷Lu-labeled ethylenediaminetetramethylene phosphonic acid (¹⁷⁷Lu-EDTMP) is an agent that concentrates in areas of enhanced osteoblastic activity. The potential of ¹⁷⁷Lu-EDTMP for palliation of metastatic bone pain has been documented in the recent literature. The objective of the present work was to study the efficacy and safety of the agent after administration to a limited number of patients. Methods: Ten patients (median age, 68.5 y) with disseminated skeletal metastases received a single bolus infusion of ¹⁷⁷Lu-EDTMP (3.7 GBq). All patients had painful bone metastases in more than one anatomic region that were not relieved by narcotic analgesics. The efficacy of the agent was studied by following pain scores assessed at baseline and at 4, 8, and 12 wk after therapy, by using Karnofsky indices and mobility scores, and by determining the requirement for analgesics at baseline and 4 wk after therapy. The toxicity of the agent was assessed by analyzing complete blood counts. Results: A significant reduction in the mean pain score was noted in all patients. The initial mean pain score of 8.44 dropped to 5.73 within 1 mo of treatment. Six patients who required analgesics for pain management had either reduced or completely withdrawn from their use by 4 wk. Compared with initial scans, scans obtained 1 mo after therapy also showed a decreased uptake of the radiotracer. The mobility scores of all patients were higher at 4 wk. The mean Karnofsky performance score of all patients was initially 45 and increased markedly to 69 at 4 wk. None of the patients experienced blood-related toxicity. Conclusion: ¹⁷⁷Lu-EDTMP, with only low bone marrow toxicity, provided significant pain relief to patients and considerably increased their mobility, resulting in an overall improvement in the quality of life. The results of the preliminary clinical studies indicate that ¹⁷⁷Lu-EDTMP can be considered an effective and safe therapeutic radiopharmaceutical for pain palliation of patients with disseminated skeletal disease.