LY2784544 potently inhibited the JAK2 V617F-STAT5 signaling with IC50 of 55 nM, but the IC50 for inhibiting wild type JAK2 is 2.26 uM. LY2784544 selectively inhibit the JAK2 V617F-driven cell proliferation with IC50 of 68 nM.In Ba/F3 cell model, LY2784544 can inhibit JAK2 V617F signaling and induce apoptosis with EC50 of 113 nM.
In vivo
In vivo, LY2784544 effectively inhibits STAT5 phosphorylation in Ba/F3-JAK2 V617F-GFP ascites tumor cells with a Threshold Effective Dose 50 (TED50) of 12.7 mg/kg. LY2784544 also significantly duced Ba/F3-JAK2 V617F-GFP tumor burden in the JAK2 V617F-induced MPN model with a TED50 of 13.7 mg/kg after oral treatment (BID) for 14 days.LY2784544 selectively reduced Ba/F3-JAK2 V617F-GFP tumor cells with no effect on CD71/Ter119 positive erythroid progenitors in spleens of SCID mice after oral treatment (BID) for seven days.