Therapeutic effects of a Re-complex-conjugated bisphosphonate for the palliation of metastatic bone pain in an animal model

Ogawa, Kazuma*; Mukai, Takahiro*; Asano, Daigo*; Kawashima, Hidekazu*; Kinuya, Seigo*; Shiba, Kazuhiro*; Hashimoto, Kazuyuki; Mori, Hirofumi*; Saji, Hideo*

We developed a highly stable rhenium-186 (Re)-MAG3 complex-conjugated bisphosphonate, (Re-MAG3-HBP), for the treatment of painful bone metastases. This agent showed a superior biodistribution as a bone-seeking agent in normal mice when compared with Re-HEDP. In this study, we evaluated the therapeutic effects of Re-MAG3-HBP using an animal model of bone metastasis. In the rats treated with Re-HEDP, tumor growth was comparable to that in untreated rats. In contrast, when Re-MAG3-HBP was administered, tumor growth was significantly inhibited. Allodynia induced by bone metastasis was attenuated by treatment with Re-MAG3-HBP or Re-HEDP, but Re-MAG3-HBP tended to be more effective. These results indicate that Re-MAG3-HBP could be useful as a therapeutic agent for the palliation of metastatic bone pain.