SP-141 is a novel, cell-permeable, selective and high affinity MDM2 inhibitor (Ki = 28 nM) with excellent in-vitro and in-vivo anticancer activity. SP 141 directly binds MDM2 to inhibit MDM2 expression and induce MDM2
autoubiquitination aw well as proteasomal degradation. SP 141 has been
shown to attenuate growth of breast cancer xenograft tumors.