A pan-Aurora kinase inhibitor (IC₅₀ = 3 nM for both Aurora A and B). AT9283 also potently inhibits several kinases including the JAK2 and 3 (IC₅₀’s 1.2 and 1.1 nM, respectively), c-Abl(IC₅₀ = 110 nM) and Abl/T315I (IC₅₀ = 4 nM).