Fig. 2
From: Boron delivery agents for neutron capture therapy of cancer
Some low- and high-molecular weight boron delivery agents (with the exception of #3) that have been investigated by Barth et al. (1) BPA (boronophenylalanine, Na 102 B10H10) and (2) BSH (sodium borocaptate, Na 102 B12H11SH, undecahydro-mercapto-closo-dodecaborate) are the only two drugs in clinical use. (3) GB–10 (sodium decaborate, Na2B12H) has been used in only a few animal studies; although at one time it had an approved U.S. Food and Drug Administration (FDA) Investigational New Drug designation (IND), it never has been used clinically. (4) N5-2OH (3-[5-{2-(2,3-dihydroxyprop-1-yl)-o-carboran-1-yl}pentan-1-yl] thymidine) is a carboranyl thymidine analogue (CAT) that yielded promising results in the RG2, but not the F98, rat glioma models following intracerebral convection-enhanced delivery (i.c. CED). (5) cis-ABCHC and trans-ABCHC (1-amino-3-borono-cycloheptanecarboxylic acid) as a racemic mixture is an unnatural amino acid that has in vivo uptake comparable to BPA in the B16 melanoma model, but far superior tumor:blood boron concentration ratios compared with BPA. (6) VEGF-BD-Cy5 is a heavily boronated vascular endothelial growth factor (VEGF) linked to Cy5 for near infrared imaging of the construct. (7) H2-DCP (di [3,5-(nido-carboranylphenyl) tetra-benzoporphyrin]) is one of a group of carboranyl porphyrins containing multiple carborane clusters, which show high in vitro cellular uptake. In vivo BNCT following i.c. CED yielded survival data comparable to that of intravenously administered BPA (8) C225-G5-B1000 is a heavily boronated form of the monoclonal antibody cetuximab that specifically targets the human epidermal growth factor receptor (EGFR), which has been used for BNCT of the F98EGFR rat glioma. (9) EGFR-targeting, boron-containing immunoliposomes with cetuximab as the targeting moiety