Rhenium-188 hydroxyethylidene diphosphonate (Re-188 HEDP) is a new
radiopharmaceutical for treatment of metastatic bone
pain. Re-188 is a generator-produced
radionuclide emitting high energy beta and gamma rays and having a relative short physical half-life makes it of especially interesting for therapeutic purpose. Seven patients (pts) with multiple painful bone
metastases were treated with Re-188
HEDP. Five pts with
prostate cancer and 2 pts with
breast cancer received a fixed activity of 3000 MBq of Re-188
HEDP intravenously in two steps. Complete blood counts were determined, blood chemistry examinations and urine-analysis were performed before and 1, 2, 3, 4, 6, 8, 12 weeks following the treatment. A visual analogue score, a verbal rating scale, the Spitzer index and the Karnofsky score were used to assess
pain and performance status. Three hours after Re-188
HEDP administration at 1 m from the anterior mid-trunk of the pts gamma and at the patient body surface beta-radiation dose measurements were made, together with urine radioactivity measurements. Three pts become
pain-free, 2 pts exhibited partial
pain improvement and 1 patient gave no response to the Re-188
HEDP therapy. In 1 patient due to central nervous system
metastasis the modification of the
pain intensity could not be evaluated. Three pts displayed a flare reaction within 1 week after the treatment. Transient decreases in platelet and white blood cell counts were observed. There were no significant changes in the liver and renal functions. Radiation dose rate values of 6.3 +/- 1.0 microSv/h for gamma, and of 183 +/- 40 s-1 for beta-radiation were found. 25-32% of the administered dose was eliminated via the urinary tract in the first three hours. The preliminary data suggests that Re-188
HEDP is an effective
radiopharmaceutical in treatment for metastatic bone
pain. An administered activity of 3000 MBq can bring about a
pain reduction without causing any clinically significant bone marrow toxicity.