Back to Journals » Journal of Experimental Pharmacology » Volume 8

Comprehensive kinase profile of pacritinib, a nonmyelosuppressive Janus kinase 2 inhibitor

Authors Singer J, Al-Fayoumi S, Ma H, Komrokji R, Mesa R, Verstovsek S

Received 16 April 2016

Accepted for publication 21 June 2016

Published 16 August 2016 Volume 2016:8 Pages 11—19


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 3

Editor who approved publication: Professor Bal Lokeshwar

Jack W Singer,1 Suliman Al-Fayoumi,1 Haiching Ma,2 Rami S Komrokji,3 Ruben Mesa,4 Srdan Verstovsek5

1Translational Medicine, CTI BioPharma Corp., Seattle, WA, 2Department of Research and Development, Reaction Biology, Malvern, PA, 3Department of Malignant Hematology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 4Division of Hematology and Medical Oncology, Mayo Clinic Cancer Center, Scottsdale, AZ, 5Department of Leukemia, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA

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.

Keywords: kinase analysis, myelofibrosis, hematologic malignancies, Janus kinase 2, JAK2V617F, fms-like receptor tyrosine kinase 3

Creative Commons License This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at and incorporate the Creative Commons Attribution - Non Commercial (unported, v3.0) License. By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms.

Download Article [PDF]  View Full Text [HTML][Machine readable]