A new boronated porphyrin (STA-BX909) for neutron capture therapy: an in vitro survival assay and in vivo tissue uptake study

A new boronated porphyrin compound (STA-BX909) was developed as a possible agent for boron neutron capture therapy. The boron concentration was measur ed by an in vivo rat experimental brain tumor model and an in vitro cell cu lture study. This agent was compared to sodium borocaptate (BSH) which has been used in clinical trials of boron neutron capture therapy. In the 9L ra t brain tumor model, STA-BX909 achieved a higher boron tumor/blood ratio 24 h after injection in comparison to BSH. A boron concentration study in cul tured glioma cell lines (U-251, U-87, 9L) demonstrated an increased boron c oncentration as a function of exposure time to STA-BX909, while the boron c oncentration remained stable with increasing exposure time to BSH. Use of a colony forming assay with thermal neutron irradiation revealed more cytoto xicity with STA-BX909 than BSH when the same concentration of B-10 was admi nistered. We concluded that STA-BX909 may be an effective drug for use in b oron neutron capture therapy and that it merits further investigation. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.