Janus kinase 1/2 (JAK1/2)

Absorption, Distribution and Excretion
Momelotinib is rapidly absorbed after oral administration, with a bioavailability of 97%. At the maximum recommended dose, the mean (%CV) steady-state Cmax is 479 ng/mL (61%), and the mean (%CV) AUC is 3,288 ng·h/mL (60%). Momelotinib exposure (i.e., Cmax and AUC) increases proportionally with dose from 100 mg to 300 mg (0.5 to 1.5 times the maximum recommended dose), but the increase in exposure is less proportional to the dose in the dose range of 400 mg to 800 mg (2 to 4 times the maximum recommended dose). No clinically significant accumulation is observed. Steady-state Tmax is 2 hours after administration (Q1: 1 hour; Q3: 3 hours). In healthy subjects, no clinically significant differences in the pharmacokinetics of Momelotinib were observed regardless of whether a high-fat meal (800 kcal; 50% fat) or a low-fat meal (400 kcal; 20% fat) was consumed. Momelotinib is primarily excreted in feces, with a small amount excreted in urine. Following a single oral administration of radiolabeled Momelotinib to healthy subjects, approximately 69% of the total radioactive dose was recovered in feces, with M14 accounting for 21.4%, Momelotinib and M21 each accounting for 13%, and the remaining 22% as 12 other metabolites. Approximately 28% of the radioactive material was recovered in urine, with M21 being the major metabolite. The mean steady-state apparent volume of distribution (%CV) was 984 L (118%). The mean clearance (%CV) was 103 L/h (87%).

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Metabolism/Metabolites Momelotinib is metabolized by a variety of cytochrome P450 (CYP) enzymes, including CYP3A4 (36%), CYP2C8 (19%), CYP2C9 (17%), CYP2C19 (19%), and CYP1A2 (9%). M21 is initially generated by the oxidation of the morpholine ring by the above-mentioned CYP enzymes, and subsequently metabolized by aldehyde oxidases. M21 is the major metabolite in the human body, retaining approximately 40% of the pharmacological activity of the parent drug. The average AUC ratio of M21 to momelotinib ranges from 1.4 to 2.1. Momelotinib can undergo amide hydrolysis, N-dealkylation, nitrile hydrolysis, nitrile oxidation, and glucuronidation.

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Biological Half-Life The elimination half-life of momelotinib and its metabolite M21 is 4 to 8 hours.

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Oral bioavailability in rats: Male Sprague-Dawley rats (250–300 g) were administered Momelotinib (LM1149; CYT387; CYT11387) by gavage (10 mg/kg) or intravenous injection (2 mg/kg): - Oral bioavailability = 50%; - Oral administration: Cmax = 3.1 μg/mL (Tmax = 1.6 h), terminal half-life (t1/2) = 4.3 h, AUC0-24h = 17.2 μg·h/mL; - Intravenous administration: Cmax = 7.9 μg/mL, t1/2 = 3.9 h, AUC0-∞ = 34.4 μg·h/mL [1]
- Plasma protein binding rate: In human plasma, the protein binding rate of Momelotinib (LM1149; CYT387; CYT11387) was 93% (as determined by 37°C equilibrium dialysis method) [1]
- MPN mouse tissue distribution: Two hours after oral administration of Momelotinib (LM1149; CYT387; CYT11387) (60 mg/kg) to MPN mice, the bone marrow concentration was 4.8 μg/g and the spleen concentration was 4.5 μg/g, which was about 1.5 times the plasma concentration (3.2 μg/mL) [3]

Hepatotoxicity
In published pre-registration clinical trials of Momelotinib, the incidence of elevated serum ALT or AST levels ranged from 21% to 31%, with 0.5% to 2.0% of patients having ALT or AST levels exceeding the upper limit of normal (ULN) by 5 times, and 0.5% having ALT or AST levels exceeding the ULN by 20 times. In the safety cohort of 448 patients treated with Momelotinib, two patients experienced clinically significant but spontaneously resolving liver injury with jaundice. Another patient developed liver injury with jaundice, suspected to be caused by hepatitis B virus reactivation. This liver injury was typically hepatocellular, without immune hypersensitivity or autoimmune characteristics, and appeared 2 to 4 months after treatment, resolving rapidly upon discontinuation of the drug. Peak ALT elevations ranged from 308 to 1178 U/L, and peak bilirubin elevations ranged from 2.3 to 7.0 mg/dL. There were no deaths due to liver failure. Since its approval and wider clinical application, no further cases of elevated serum enzymes or bilirubin or clinically significant liver injury have been reported, but the use of this drug is limited.
Probability Score: D (May cause clinically significant liver injury, including hepatitis B virus reactivation).

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Effects during pregnancy and lactation>
◉ Overview of use during lactation
There is currently no information regarding the clinical use of Momelotinib during lactation. Because Momelotinib binds to plasma proteins at a rate of 91%, its content in breast milk may be low. The manufacturer recommends discontinuing breastfeeding during Momelotinib treatment and for at least one week after the last dose.
◉ Effects on breastfed infants
No published information found as of the revision date.
◉ Effects on lactation and breast milk
No published information found as of the revision date.

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Protein binding>
In healthy volunteers, Momelotinib binds to plasma proteins at a rate of 91%.

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Repeated-dose toxicity in rodents: Male/female Sprague-Dawley rats (n=4 per sex per group) were treated with momelotinib (LM1149; CYT387; CYT11387) (5/30/100 mg/kg, orally, once daily) for 28 days: - No deaths; No adverse events observed at the NOAEL of 30 mg/kg; - 100 mg/kg dose group: Mild thrombocytopenia (platelet count decreased by 20% compared to the control group), no histopathological changes in the liver and kidneys; no changes in serum ALT/AST/creatinine levels [1]
- Safety in MPN mice: Momelotinib (LM1149; CYT387; CYT11387) (maximum dose 60 mg/kg, orally, for 28 days) resulted in a weight loss of ≤4%, with no significant toxicity (e.g., somnolence, diarrhea), and normal serum creatinine/BUN levels [3]
- Safety in normal cells in vitro: After treating human peripheral blood mononuclear cells (PBMCs) with Momelotinib (LM1149; CYT387; CYT11387) (≤10 μM) for 72 hours, cell viability was >85% (MTT assay), and no significant apoptosis was observed [1]

Momelotinib dihydrochloride is the dihydrochloride form of Momelotinib, a small molecule inhibitor with high oral bioavailability. It inhibits wild-type (WT) Janus kinases 1 and 2 (JAK1/2), the JAK2 mutant JAK2V617F, and activin A receptor type 1 (ACVR1; activin receptor-like kinase 2; ALK2), exhibiting antitumor activity. After oral administration, Momelotinib competes with JAK1/2 for ATP binding sites, thereby inhibiting JAK1/2 activation, suppressing the JAK-STAT signaling pathway, and inducing apoptosis in JAK1/2-expressing tumor cells, reducing tumor cell proliferation. Furthermore, inhibition of ALK2 prevents hepatic hepcidin production, increases iron utilization, and promotes erythrocyte (RBC) production. JAK2 is the most common mutated gene in bcr-abl-negative myeloproliferative disorders; the JAK2V617F gain-of-function mutation involves a modification of valine to phenylalanine at position 617. The JAK-STAT signaling pathway is a major mediator of cytokine activity and is frequently dysregulated in a variety of tumor cell types.

C23H24CL2N6O2

487.381662368774

486.134

C, 56.68; H, 4.96; Cl, 14.55; N, 17.24; O, 6.57

1380317-28-1

1056634-68-4;1380317-28-1 (HCl); Momelotinib sulfate;1056636-06-6;Momelotinib Mesylate;1056636-07-7;

57345482

Typically exists as solid at room temperature

5.11

4

7

6

33

615

0

Cl.Cl.O1CCN(C2C=CC(=CC=2)NC2N=CC=C(C3C=CC(C(NCC#N)=O)=CC=3)N=2)CC1

IPNATXQRPWRHKD-UHFFFAOYSA-N

InChI=1S/C23H22N6O2.2ClH/c24-10-12-25-22(30)18-3-1-17(2-4-18)21-9-11-26-23(28-21)27-19-5-7-20(8-6-19)29-13-15-31-16-14-29/h1-9,11H,12-16H2,(H,25,30)(H,26,27,28)2*1H

N-(Cyanomethyl)-4-[2-(4-morpholin-4-ylanilino)pyrimidin-4-yl]benzamide dihydrochloride

Momelotinib HCl CYT387 ；dihydrochloride; Momelotinib dihydrochloride; CYT387 HCl; CYT-387; CYT 387; CTY387; CYT11387; CYT 11387; CYT-11387; Ojjaara

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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 (Please use freshly prepared in vivo formulations for optimal results.)