R1530 is the multikinase inhibitor with potential antiangiogenesis and antineoplastic activities. R1530 is also a mitosis-angiogenesis inhibitor (MAI) that inhibits multiple receptor tyrosine kinases involved in angiogenesis, such as vascular endothelial growth factor receptor (VEGFR)-1, -2, -3, platelet-derived growth factor receptor (PDGFR) beta, FMS-like tyrosine kinase (Flt)-3, and fibroblast growth factor receptor (FGFR) -1, -2. In addition, this agent exhibits anti-proliferative activity by initiating mitotic arrest and inducing apoptosis. In the presence of R1530, polyploid cancer cells underwent apoptosis or became senescent which translated into potent in vitro and in vivo efficacy. Normal proliferating cells were resistant to R1530-induced polyploidy thus supporting the rationale for cancer therapy by induced polyploidy. Mitotic checkpoint kinase BubR1 was found downregulated during R1530-induced exit from mitosis, a likely consequence of PLK4 inhibition. R1530 strongly inhibited human tumor cell proliferation and growth factor-driven proliferation of endothelial and fibroblast cells. Significant tumor growth inhibition was demonstrated in a lung cancer xenograft model with a range of once daily, weekly and twice-weekly doses of R1530. Daily doses were most effective in the lung cancer model and also had significant growth inhibitory effects in models of colorectal, prostate, and breast tumors. Tumor regression occurred in all models treated with the maximum tolerated daily dose. The doses of 25 and 50 mg/kg QD resulted in biologically significant increased survival in all tested models. After oral administration in nude mice, R1530 showed good tissue penetration. R1530 had been in phase I clinical trials by Hoffmann-La Roche, Inc. for the treatment of advanced solid tumors. However, the clinical development of R1530 was discontinued.