Rhenium-188 HEDP to treat painful bone metastases

Purpose: Rhenium-188 hydroxyethylidine diphosphonate (HEDP) is a new and attractive radiopharmaceutical that localizes in skeletal metastases and emits beta particles that may be therapeutically beneficial. In this study, the therapeutic efficacy of Re-188 HEDP was investigated in an uncontrolled initial trial of 61 patients with different types of advanced cancer for the palliation of painful bone metastases. Materials and Methods: Sixty-one patients with painful bone metastases of lung, prostate, breast, renal, rhinopharyngeal, and bladder cancers were treated with 1.1 GBq (31 mCi) to 6.9 GBq (188 mCi) Re-188 HEDP. After treatment, the patients were followed at weekly intervals for the first 2 months and monthly thereafter for as long as 1 year. Hematologic function tests were also performed before and after treatment for 6 weeks. Pain responses were scored according to a three-point pain-rating scale as complete, significant, and minimal. Results: Prompt and significant relief of bone pain occurred in 80% of patients overall. Of the specific tumor types, pain relief was achieved in 77% of patients with lung cancer, in 80% with prostate cancer, in 83% with breast cancer, in 100% with bladder cancer, in 50% with renal cancer, in 50% with rhinopharyngeal cancer, and in 87% of patients with other tumor types, with no severe side effects or hematopoietic toxicity. Conclusion: This large clinical trial verified that Re-188 HEDP is a useful radiopharmaceutical agent to treat painful bone metastases from various tumor types.