Clinical use of bone-targeting radiopharmaceuticals with focus on alpha-emitters - Abstract

Various single or multi-modality therapeutic options are available to treat pain of bone metastasis in patients with prostate cancer.

Different radionuclides that emit β-rays such as 153Samarium and 89Strontium and achieve palliation are commercially available. In contrast to β-emitters, 223Radium as a α-emitter has a short path-length. The advantage of the α-emitter is thus a highly localized biological effect that is caused by radiation induced DNA double-strand breaks and subsequent cell killing and/or limited effectiveness of cellular repair mechanisms. Due to the limited range of the α-particles the bone surface to red bone marrow dose ratio is also lower for 223Radium which is expressed in a lower myelotoxicity. The α emitter 223Radium dichloride is the first radiopharmaceutical that significantly prolongs life in castrate resistant prostate cancer patients with wide-spread bone metastatic disease. In a phase III, randomized, double-blind, placebo-controlled study 921 patients with castration-resistant prostate cancer and bone metastases were randomly assigned. The analysis confirmed the 223Radium survival benefit compared to the placebo (median, 14.9 mo vs 11.3 mo; P < 0.001). In addition, the treatment results in pain palliation and thus, improved quality of life and a delay of skeletal related events. At the same time the toxicity profile of 223Radium was favourable. Since May 2013, 223Radium dichloride (Xofigo®) is approved by the US Food and Drug Administration.

Written by:
Wieder HA, Lassmann M, Allen-Auerbach MS, Czernin J, Herrmann K.   Are you the author?
Hinrich A Wieder, Department of Radiology, Zentrum für Radiologie und Nuklearmedizin, 41515 Grevenbroich, Germany.

Reference: World J Radiol. 2014 Jul 28;6(7):480-5.
doi: 10.4329/wjr.v6.i7.480

PubMed Abstract
PMID: 25071888