Radiolanthanide-labeled HA particles in the treatment of rheumatoid arthritis: ready-to-use cold kits for rapid formulation in hospital radiopharmacy

摘要

Hydroxyapatite (HA) [Ca-10(PO4)(6)(OH)(2)] particles radiolabeled with a variety of beta(-) emitting lanthanide radionuclides and also pseudolanthanide Y-90 have been proposed for the treatment of arthritis. A ready-to-use cold kit of HA particles (1-10 A mu m size) was developed for fast and convenient formulation of radiolanthanide-labeled HA particles at hospital radiopharmacy. Six radionuclides namely, Er-169, Lu-177, Sm-153, Ho-166, Pr-142 and Y-90, having beta(-) emissions of a wide range of energy [E-beta(max) = 0.34-2.28 MeV] were identified and produced by thermal neutron activation. Clinical doses of HA particles labeled with these radionuclides were prepared in high yield (> 97 %) and radiochemical purity (> 99 %) using the cold kits. Pre-clinical studies of Lu-177-HA carried out in Wistar rats bearing arthritis in knee joints revealed no leakage of the activity from the joints. In preliminary clinical investigation using 333 +/- A 46 MBq doses of the same preparation, significant improvement in the disease conditions was reported in patients with chronic rheumatoid arthritis of knee joints.