Analysis of mice treated with INC424, HU, or vehicle and transplanted with JAK2-V617F BM cells expressing GFP (from SclCre;FF1;GFP mice with a PV phenotype) and Jak2 wild-type (from C57BL/6 mice) BM cells in a 1:1 ratio. (A) Schematic drawing of the experimental setup. WT indicates wild-type. (B) Body weight during treatment. Black indicates vehicle (0.5% hydroxypropyl methylcellulose); dark blue, INC424 90 mg/kg BID; yellow, HU 10 mg/kg BID; bright orange, HU 50 mg/kg BID; and dark orange, HU 100 mg/kg BID. (C) Spleen weights. Color coding is as in panel B. (D) Blood counts and flow cytometry data showing the chimerism (percentage of GFP⁺ cells) after 21 days of treatment. (E) Reticulocyte counts. Color coding is as in panel B. (F) Chimerism (percentage of GFP⁺ cells) in BM (top panel) and spleen (bottom panel) after 21 days of treatment. One-way ANOVA is shown. ns indicates not significant. *P ≤ .05; **P ≤ .01; ***P ≤ .001.