This is an open-label, positron emission tomography (PET) imaging Proof of Biology (POB) study to determine whether CC 90011 reverses, by the induction of androgen receptor (AR) expression, the castration resistance, due to lineage switch, in participants with mCRPC that have failed enzalutamide as last prior therapy. This study aims to assess whether CC-90011 can induce AR expression and, consequently, re-sensitize tumors to anti-hormonal therapy.