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A tumor localizing radiation sensitizer, KADT-F10, in which two molecules of nitroimidazole fluorinate, KU2280, are bound to side chain residues of a tumor localizing Mn-porphyrin was synthesized and evaluated. Suppression of tumor growth was significantly higher in a group of mice in which a total 50mg/kg KADT-F10 was administered before radiotherapy at 50 Gly (A: n=7) than in a group of mice in which radiotherapy alone was done (B: n=7). In group B, all mice died within 73 days after radiotherapy, while in group A, the tumor disappeared in five of seven mice, and three of seven mice completely recovered 120 days after radiotherapy. Clear magnetic resonance images of SCCVII tumor were obtained 1.5h after KADTF-10 administration.

A new boronated porphyrin compound (STA-BX909) was developed as a possible agent for boron neutron capture therapy. The boron concentration was measured by an in vivo rat experimental brain tumor model and an in vitro cell culture study. This agent was compared to sodium borocaptate (BSH) which has been used in clinical trials of boron neutron capture therapy. In the 9L rat 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 cultured glioma cell lines (U-251, U-87, 9L) demonstrated an increased boron concentration as a function of exposure time to STA-BX909, while the boron concentration remained stable with increasing exposure time to BSH. Use of a colony forming assay with thermal neutron irradiation revealed more cytotoxicity with STA-BX909 than BSH when the same concentration of 10B was administered. We concluded that STA-BX909 may be an effective drug for use in boron neutron capture therapy and that it merits further investigation.