IRAK1 and myelodysplastic syndrome: Pacritinib inhibits IRAK1 (an IL-1 receptor kinase), and IRAK1 is commonly mutated in two dysregulated hematopoiesis diseases (myelodysplastic syndromes and Fanconi anemia).432 Pacritinib is currently mainly used in MF and AML patients with a dosage of 200 mg twice a day or 400 mg once a day.433 In patients with MF and thrombocytopenia, 200 mg of pacritinib twice daily is better than 400 mg of pacritinib once daily in terms of hemoglobin and reduction in transfusion burden.