title: Comprehensive kinase profile of pacritinib, a nonmyelosuppressive Janus kinase 2 inhibitor.
abstract: Pacritinib, potent inhibitor of Janus kinase 2 (JAK2), JAK2V617F, and fms-like receptor tyrosine kinase 3, is in Phase III development in myelofibrosis. Among type 1 inhibitors, pacritinib shows a lack of myelosuppression at doses that both inhibit JAK2/signal transducer and activator of transcription 3 pathway and demonstrate clinical efficacy. To elucidate these mechanisms and identify other disease targets, a kinome analysis screened 439 recombinant kinases at 100 nM pacritinib concentration. For kinases with >50% inhibition, pacritinib was titrated from 1 to 100 nM. JAK2, JAK2V617F, FLT3, colony-stimulating factor 1 receptor, and interleukin-1 receptor-associated kinase 1 achieved half-maximal inhibitory concentrations <50 nM. Pacritinib did not inhibit JAK1 (82% control at 100 nM). Lack of myelosuppression may stem from inhibiting JAK2 without affecting JAK1 and reducing hematopoietic inhibitory cytokines by suppressing interleukin-1 receptor-associated kinase 1 or colony-stimulating factor 1 receptor. The pacritinib kinome suggests therapeutic utility in acute myeloid leukemia, myelodysplastic syndrome, chronic myelomonocytic leukemia, solid tumors, and inflammatory conditions.
authors: Translational Medicine, CTI BioPharma Corp., Seattle, WA.
authors: Jack W
authors: JW
authors: Singer
authors: Translational Medicine, CTI BioPharma Corp., Seattle, WA.
authors: Suliman
authors: S
authors: Al-Fayoumi
authors: Department of Research and Development, Reaction Biology, Malvern, PA.
authors: Haiching
authors: H
authors: Ma
authors: Department of Malignant Hematology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL.
authors: Rami S
authors: RS
authors: Komrokji
authors: Division of Hematology and Medical Oncology, Mayo Clinic Cancer Center, Scottsdale, AZ.
authors: Ruben
authors: R
authors: Mesa
authors: Department of Leukemia, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
authors: Srdan
authors: S
authors: Verstovsek
keywords: JAK2V617F; Janus kinase 2; fms-like receptor tyrosine kinase 3; hematologic malignancies; kinase analysis; myelofibrosis