Pacritinib is a relatively non-myelosuppressive JAK2/interleukin-1 receptor associated kinase 1 (IRAK1) inhibitor in advanced clinical development for patients with severe thrombocytopenia [7]; the approved JAK inhibitors are not recommended for this subgroup of patients because they exacerbate cytopenias. This evidence concerns the gene JAK2 and Thrombocytopenia.