HER‐2‐Targeted Boron Neutron Capture Therapy with Carborane‐integrated Immunoliposomes Prepared via an Exchanging Reaction

Boron neutron capture therapy (BNCT) is a promising modality for cancer treatment because of its minimal invasiveness. To maximize the therapeutic benefits of BNCT, the development of efficient platforms for the delivery of boron agents is indispensable. Here, carborane‐integrated immunoliposomes were prepared via an exchanging reaction to achieve HER‐2‐targeted BNCT. The conjugation of an anti‐HER‐2 antibody to carborane‐integrated liposomes successfully endowed these liposomes with targeting properties toward HER‐2‐overexpressing human ovarian cancer cells (SK‐OV3); the resulting BNCT activity toward SK‐OV3 cells obtained using the current immunoliposomal system was 14‐fold that of the l‐BPA/fructose complex, which is a clinically available boron agent. Moreover, the growth of spheroids treated with this system followed by thermal neutron irradiation was significantly suppressed compared with treatment with the l‐BPA/fructose complex. Carborane integrated immunoliposome was prepared by host exchanging reaction as a boron agent for BNCT.