A potent JAK2/FLT3 inhibitor. Displays equipotent activity against JAK2 (I₅₀ = 23 nM) and FLT3 (IC₅₀ = 22 nM). SB1518 displays potent anti-proliferative effects on myeloid and lymphoid cell lines driven by mutant or wild-type JAK2 or FLT3, resulting from cell cycle arrest and induction of apoptosis.