3 Hydroxy Midostaurin Epimer 2 (CGP52421 Epimer 2)

(R)-3-Hydroxy Midostaurin ((R)-CGP52421; compound 5) has IC ₅₀ values in the range of 200-400 nM against the ITD and D835Y mutants and low micromolar activity against the wild-type enzyme.
The epimeric mixture of metabolites ((R)-3-Hydroxy Midostaurin + (S)-3-Hydroxy Midostaurin) substantially inhibits the proliferation of only the Tel-PDGFRβ (GI ₅₀ =63 nM), KIT D816V (GI ₅₀ =320 nM), and FLT3-ITD (GI ₅₀ =650 nM) BaF3 cell lines, while the wild-type cells are relatively insensitive.