Pacritinib (SB1518)
For research use only.
Catalog No.S8057
6 publications
CAS No. 937272-79-2
Pacritinib (SB1518) is a potent and selective inhibitor of Janus Kinase 2 (JAK2) and Fms-Like Tyrosine Kinase-3 (FLT3) with IC50s of 23 and 22 nM in cell-free assays, respectively. Phase 3.
Purity & Quality Control
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Biological Activity
| Description | Pacritinib (SB1518) is a potent and selective inhibitor of Janus Kinase 2 (JAK2) and Fms-Like Tyrosine Kinase-3 (FLT3) with IC50s of 23 and 22 nM in cell-free assays, respectively. Phase 3. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Features | Dual JAK2/FLT3 inhibitor that has progressed to Phase III clinical trials for treatment of Myelofibrosis. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Targets |
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| In vitro |
Pacritinib is a potent inhibitor of both wild-type JAK2 and JAK2V617F mutant (IC50= 19 nM) that is present in high frequencies among patients with MPD. Relative to JAK2, Pacritinib is two-fold less potent against TYK2 (IC50= 50 nM), 23-fold less potent against JAK3 (IC50= 520 nM) and 56-fold less potent against JAK1 (IC50= 1280 nM). Pacritinib effectively permeates cells to modulate signaling pathways downstream of JAK2, whether agonist activated or mutationally activated. Pacritinib induces apoptosis, cell cycle arrest and antiproliferative effects in JAK2WT- and JAK2V617F-dependent cells. Pacritinib inhibits cell proliferation of Karpas 1106P and Ba/F3-JAK2V617F with IC50 of 348 and 160 nM, respectively. Pacritinib inhibits endogenous colony growth derived from erythroid and myeloid progenitors with IC50 of 63 and 53 nM , respectively. [1] SB1518 also inhibits FLT3 and its mutant FLT3-D835Y(IC50= 6 nM ). Pacritinib inhibits FLT3 phosphorylation and downstream STAT, MAPK and PI3K signaling in FLT3-internal-tandem duplication (ITD), FLT3-wt cells and primary AML blast cells. Pacritinib treatment leads to a dose-dependent decrease of pFLT3, pSTAT5, pERK1/2 and pAkt in FLT3-ITD harboring MV4-11 cells with IC50 of 80, 40, 33 and 29 nM , respectively. Treatment of the primary AML blast cells with Pacritinib for 3 h leads to a dose-dependent decrease of pFLT3, pSTAT3 and pSTAT5 with an IC50 below 0.5 μM. Pacritinib induces apoptosis, cell cycle arrest and anti-proliferative effects in FLT3-mutant and FLT3-wt cells. Pacritinib inhibits cell proliferation of FLT3-ITD-harboring cells MV4-11 and primary AML blast cells with IC50s of 47 nM and 0.19-1.3 μM, respectively. [2] |
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| Cell Data |
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| In vivo | Pacritinib administrated at 150 mg/kg p.o. q.d. to JAK2V617F-dependent xenograft model, significantly ameliorates splenomegaly and hepatomegaly symptoms, with 60% normalization of spleen weight and 92% normalization of liver weight and is well tolerated without significant weight loss or any hematological toxicities, including thrombocytopenia and anemia. Pacritinib induces dose-dependent inhibition of tumor growth of JAK2V617F-dependent SET-2 xenograft model (40% for 75 mg/kg and 61% for 150 mg/kg). [1] Pacritinib is efficacious in FLT3-ITD-bearing MV4-11 xenograft models. Pacritinib treated once daily for 21 consecutive days, induces dose-dependent inhibition of tumor growth (38% for 25 mg/kg, 92% for 50 mg/kg and 121% for 100 mg/kg). Complete regression is observed in 3/10 and 8/8 mice for the 50 and 100 mg/kg/day groups, respectively. [2] |
Protocol
| Kinase Assay:[1] |
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kinase activity assays: All assays are carried out in 384-well white microtiter plates. Compounds are 4-fold serially diluted in 8 steps, starting from 10 μM. The reaction mixture consisted of 25 μL assay buffer (50 mM HEPES pH 7.5, 10 mM MgCl2, 5 mM MnCl2, 1 mM DTT, 0.1 mM Na3VO4, 5 mM β-glycerol phosphate). For FLT3 assays, the reaction contains 2.0 μg/mL FLT3 enzyme, 5 μM of poly(Glu,Tyr) substrate and 4 μM of ATP. For JAK1 assays, the reaction contains 2.5 μg/mL of JAK1 enzyme, 10 μM of poly(Glu,Ala,Tyr) substrate and 1.0 μM of ATP. For JAK2 assays, the reaction contained 0.35 μg/mL of JAK2 enzyme, 10 μM of poly (Glu,Ala,Tyr) substrate and 0.15 μM of ATP. For JAK3 assays, the reaction contained 3.5 μg/mL of JAK3 enzyme, 10 μM of poly (Glu,Ala,Tyr) substrate and 6.0 μM of ATP. For TYK2 assays, the reaction contained 2.5 μg/mL of TYK2 enzyme, 10 μM of poly (Glu,Ala,Tyr) substrate and 0.15 μM of ATP. The reaction is incubated at room temperature for 2 h prior to addition of 13 μL PKLight® detection reagent. After 10 min incubation luminescent signals are read on a multi-label plate reader. |
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| Cell Research:[1] |
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| Animal Research:[1] |
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Solubility (25°C)
| In vitro | DMSO | 11 mg/mL warmed (23.27 mM) |
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| Water | Insoluble | |
| Ethanol | Insoluble |
* Please note that Selleck tests the solubility of all compounds in-house, and the actual solubility may differ slightly from published values. This is normal and is due to slight batch-to-batch variations.
Chemical Information
| Molecular Weight | 472.58 |
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| Formula | C28H32N4O3 |
| CAS No. | 937272-79-2 |
| Storage |
powder in solvent |
| Synonyms | N/A |
| Smiles | C1CCN(C1)CCOC2=C3COCC=CCOCC4=CC(=CC=C4)C5=NC(=NC=C5)NC(=C3)C=C2 |
In vivo Formulation Calculator (Clear solution)
| Step 1: Enter information below (Recommended: An additional animal making an allowance for loss during the experiment) | ||||||||||
| Dosage | mg/kg |  |
Average weight of animals | g | |
Dosing volume per animal | ul | |
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| Step 2: Enter the in vivo formulation () | ||||||||||
| % DMSO % % Tween 80 % ddH2O | ||||||||||
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Calculation results:
Working concentration： mg/ml；
Method for preparing DMSO master liquid: ： mg drug pre-dissolved in μL DMSO (Master liquid concentration mg/mL，)
Method for preparing in vivo formulation：Take μL DMSO master liquid, next addμL PEG300， mix and clarify, next addμL Tween 80，mix and clarify, next add μL ddH2O，mix and clarify.
1.Please make sure the liquid is clear before adding the next solvent.
2.Be sure to add the solvent(s) in order. You must ensure that the solution obtained, in the previous addition, is a clear solution before proceeding to add the next solvent. Physical methods such as vortex, ultrasound or hot water bath can be used to aid dissolving.
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Molarity Calculator
Clinical Trial Information
| NCT Number | Recruitment | interventions | Conditions | Sponsor/Collaborators | Start Date | Phases |
|---|---|---|---|---|---|---|
| NCT04520269 | Recruiting | Drug: Pacritinib | Breast Cancer | National University Hospital Singapore | July 13 2020 | Phase 1|Phase 2 |
| NCT03165734 | Recruiting | Drug: Pacritinib|Drug: Physician''s Choice medications | Primary Myelofibrosis|Post-polycythemia Vera Myelofibrosis|Post-essential Thrombocythemia Myelofibrosis | CTI BioPharma|PSI CRO AG | June 26 2017 | Phase 3 |
| NCT02677948 | Withdrawn | Drug: Pacritinib|Drug: Ibrutinib | Chronic Lymphocytic Leukemia|Lymphoma Small Lymphocytic | University of Michigan Rogel Cancer Center | October 2016 | Phase 1|Phase 2 |
| NCT02584777 | Withdrawn | Biological: Pacritinib | Primary Myelofibrosis | Baxalta now part of Shire|CTI BioPharma|Shire | November 2015 | Phase 2 |
| NCT02765724 | Completed | Drug: Pacritinib | Myelofibrosis | CTI BioPharma|SGS S.A. | January 2015 | Phase 1 |
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