Fig. 1

Changes in bone marrow (BM) fibrosis at 48 months following ruxolitinib (a, b) and hydroxyurea (c, d) therapy. Ruxolitinib therapy induced a significant regression of BM fibrosis from baseline grade 3 (a) to grade 0 (b). Hydroxyurea treatment had no impact on reversal of BM fibrosis; biopsy at baseline revealed a grade 1 (c), and 48 months trephine showed an increase in reticulin to grade 2 (d)