Kvasnicka HM, et al. - The oral Janus kinase (JAK) 1/JAK2 inhibitor ruxolitinib has been shown to improve splenomegaly, symptom burden, and overall survival in patients with intermediate-2 or high-risk myelofibrosis (MF) compared with placebo or best available therapy (BAT). In this current investigation, it was demonstrated that ruxolitinib therapy for a long duration could reverse or markedly delay bone marrow (BM) fibrosis progression in advanced MF when compared with matching patients treated with the BAT. This suggests that sustained JAK inhibition may be disease-modifying.