WHI-P154 is a potent JAK3 inhibitor (IC₅₀ of 1.8 μM). It displays no activity against JAK1 or JAK2. Also inhibits EGFR, Src, Abl, VEGFR and MAPK, and prevents Stat3, but not Stat5 phosphorylation.  Induces differentiation of neural progenitor cells