Roxadustat appears to be a safe and viable option for patients with myelofibrosis (MF) who develop anemia after receiving ruxolitinib, according to a letter to the editor in the Annals of Hematology

Janus kinase (JAK) inhibitor therapy has been the mainstay of treatment for over a decade; however, anemia is a known adverse effect of ruxolitinib, one of the main correlates of JAK inhibitor therapy. This adverse effect has created a need for therapeutic options with the capacity to reverse anemia in these patients. 

Roxadustat is an orally available hypoxia-inducible factor prolyl hydroxylase (HIF-PH) inhibitor that simultaneously increases the transcription of endogenous erythropoietin.

“We report two myelofibrosis (MF) cases with continuously transfusion-dependent anemia after ruxolitinib treatment, which was corrected by roxadustat (FG-4592), a novel, orally bioavailable, heterocyclic small molecule,” the authors wrote.

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The first case involved a 65-year-old man with a history of splenomegaly and constitutional symptoms. He had received an essential thrombocythemia (ET) diagnosis 6 years prior, and his diagnosis was changed to post-ET MF with a Dynamic International Prognostic Scoring System (DIPSS) risk of intermediate-2 after admission. His hemoglobin level at the time of admission was 68 g/L. 

After 6 months of treatment with roxadustat, his hemoglobin level increased to 83 g/L and his spleen reduced to be only 2 cm below the costal margin. Similarly, the percentage of bone marrow erythroblasts increased by approximately 7%.

The second patient had a 2-year history of anemia and splenomegaly that had markedly deteriorated over recent months, reaching a hemoglobin level of 76 g/L. Nine months after the initiation of roxadustat, his hemoglobin levels remained stable without any MF symptoms and the erythrocyte count in the bone marrow increased by approximately 3%.

The improvement in hemoglobin levels in both cases was superior to baseline levels before receiving ruxolitinib and after receiving a red blood cell transfusion, which significantly increased hemoglobin levels. 

“These cases suggest a new choice in MF-related anemia and ruxolitinib-induced anemia and warrant further clinical trials and laboratory studies,” the authors concluded.


Ding K, Liu Z, Ren Y, Liu H, Fu R. Use of roxadustat (FG-4592) in ruxolitinib-treatment-related anemia of two myelofibrosis patients. Ann Hematol. Published online March 13, 2023. doi:10.1007/s00277-022-04997-3