CX-5461 is a potent and orally bioavailable inhibitor of Pol I-mediated rRNA synthesis, with IC50s of 142 nM in HCT-116, 113 nM in A375, and 54 nM in MIA PaCa-2 cells, and shows little or no effect on Pol II (IC50 ≥25 μM). At 50 mg/kg, CX-5461 demonstrates in vivo antitumor activity against human solid tumors in mouse xenograft models. MW: 513.61. Purity ≥98% by HPLC