BO-264 is a highly potent and orally active inhibitor of transforming acidic coiled-coil 3 (TACC3, IC50 of 188 nM and a Kd of 1.5 nM).

TACC3:188 nM (IC50), TACC3:1.5 nM (Kd)

BO-264 demonstrated superior antiproliferative activity to the two currently reported TACC3 inhibitors, especially in aggressive breast cancer subtypes, basal and HER2+, via spindle assembly checkpoint-dependent mitotic arrest, DNA damage, and apoptosis, while the cytotoxicity against normal breast cells was negligible.?Furthermore, BO-264 significantly decreased centrosomal TACC3 during both mitosis and interphase.?BO-264 displayed potent antiproliferative activity ( 90% have less than 1 μmol/L GI50 value) in the NCI-60 cell line panel compromising of nine different cancer types.?Noteworthy, BO-264 significantly inhibited the growth of cells harboring FGFR3-TACC3 fusion, an oncogenic driver in diverse malignancies.?Importantly, its oral administration significantly impaired tumor growth in immunocompromised and immunocompetent breast and colon cancer mouse models, and increased survival without any major toxicity.?Finally, TACC3 expression has been identified as strong independent prognostic factor in breast cancer and strongly prognostic in several different cancers.