CDK9/cyc T2 (Ki = 0.626 nM); CDK9/CycT1 (Ki = 1.68 nM); CDK6/cycD1 (Ki = 2.92 nM); CDK4/Cyc D1 (Ki = 3.96 nM); CDK1/cycB (Ki = 5.4 nM); CDK1/cyc A (Ki = 9.1 nM)
Voruciclib hydrochloride targets cyclin-dependent kinases (CDKs), particularly CDK9. CDK9 is the catalytic subunit of the positive transcription elongation factor b (P-TEFb), which regulates transcription elongation. By inhibiting CDK9, Voruciclib reduces the transcription of short-lived proteins such as MCL-1, an anti-apoptotic protein frequently overexpressed in cancer. The compound also inhibits other CDKs with Ki values ranging from 0.626 nM to 9.1 nM.

Targeted downregulation of MCL-1 in ABC and GCB isoforms is shown with voruciclib hydrochloride (0.5–5 µM; 6 hours) [1]. The Ki values are 0.626 nM, 1.68 nM, 2.92 nM, respectively, for each target (e.g., CDK9/cyc T2, CDK9/cyc T1, CDK6/cyc D1, CDK4/cyc D1, CDK1/cyc B, and CDK1/cyc A for Voruciclib hydrochloride)[1].

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In vitro studies demonstrate that Voruciclib hydrochloride is a potent CDK inhibitor with Ki values of 0.626-9.1 nM. The compound potently blocks CDK9 activity and reduces MCL-1 expression. Its in vitro activity is assessed using kinase assays with purified CDK enzymes and cell-based assays measuring MCL-1 levels and cell viability. The compound shows antiproliferative activity against various cancer cell lines. Its selectivity for CDKs over other kinases is confirmed by kinase profiling panels.

Voruciclib hydrochloride (200 mpk; oral gavage) combined with venetoclax (10 mpk, 1 mpk, 50 mpk, 25 mpk in U2932, RIVA, SU-DHL-4, and NU-DHL-1, respectively) enhances tumor growth inhibition In the U2932, RIVA, SU-DHL-4 (6 days per week for 4 weeks) and NU-DHL-1 (5 days per week for 3 weeks) DLBCL models, compared with either drug alone [ 1].

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In vivo activity of Voruciclib hydrochloride has been evaluated in preclinical models. As an orally active compound, it has shown efficacy in animal models of cancer. The compound has been investigated for the treatment of various cancers, including breast cancer, mantle cell lymphoma, and acute myeloid leukemia. Its in vivo efficacy is attributed to its ability to inhibit CDK9, reduce MCL-1 expression, and induce apoptosis in tumor cells. Detailed in vivo efficacy data are reported in preclinical studies.

Reaction Biology IC50 profiling[1]
Rank order of sensitivity of 48 kinases to voruciclib hydrochloride was determined at Reaction Biology Corp. Kinase activity was measured using a filter binding assay with radioactive γ-33P-ATP as phosphate donor. The ATP concentration was near the Km values for the respective kinases. For each kinase, an IC50 value was calculated from a 10-point concentration curve of the test article and converted to Ki values. The 48 kinases studied here had been identified in previous screening experiments as the most promising target candidates.

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In vitro enzyme assays for Voruciclib hydrochloride involve measuring its inhibition of CDK kinase activity. The assay typically uses purified recombinant CDK/cyclin complexes (e.g., CDK9/cyclin T1), a peptide substrate, and ATP. The compound is incubated with the enzyme and substrates, and phosphorylation is quantified by scintillation counting using radiolabeled ATP or by ELISA. Ki values are calculated from dose-response curves. Selectivity profiling is performed using panels of other kinases to assess specificity.

Western Blot Analysis[1]
Cell Types: U2932, RIVA, OCI-LY10 cells (ABC subtype), NU-DHL-1, SU-DHL-4, SU-DHL-6 cells (GCB subtype)
Tested Concentrations: 0.5 µM , 1 µM, 2 µM, 3 µM, 4 µM, 5 µM
Incubation Duration: 6 hrs (hours)
Experimental Results: Targeted downregulation of MCL-1 was shown in both ABC and GCB subtypes.

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Cellular assays for Voruciclib hydrochloride are conducted using cancer cell lines to evaluate its effects on CDK activity, cell viability, and apoptosis. Cells are treated with varying concentrations of the compound for 24-72 hours. CDK9 inhibition is assessed by measuring the phosphorylation of RNA polymerase II (p-Ser2) and MCL-1 levels by Western blotting. Cell viability is assessed using MTT, CCK-8, or CellTiter-Glo assays. Apoptosis is evaluated by Annexin V/PI staining or caspase-3/7 activity.

Animal/Disease Models: ABC isoforms (U2932, RIVA, OCI-LY10), GCB isoforms (SU-DHL-4, NU-DHL-1) xenografted into female NOD.CB17-Prkdcscid/NCrHsd mice [1]
Doses: 200 mpk
Doses: po (oral gavage); U2932, RIVA, SU-DHL-4 (6 days per week for 4 weeks), OCI-LY10 (6 days per week for 2 weeks), NU-DHL-1 ( 5 days per week for 3 weeks)
Experimental Results: Tumor enhanced growth inhibition in U2932, RIVA, SU-DHL-4 and NU-DHL-1 models in addition to OCI-LY10 model.

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In vivo animal studies with Voruciclib hydrochloride are conducted in xenograft mouse models using human tumor cell lines. Tumor-bearing mice are treated with the compound via oral gavage at various doses. Tumor volume is measured regularly using calipers, and body weight is monitored for tolerability. At study termination, tumors are excised and analyzed for CDK9 inhibition (p-RNAP II), MCL-1 levels, apoptosis markers, and proliferation markers. Pharmacokinetic studies are also performed to assess oral bioavailability and tissue distribution.

Pharmacokinetic properties of Voruciclib hydrochloride demonstrate that the compound is orally active. The compound has a molecular weight of 506.30 and a molecular formula of C22H20Cl2F3NO₅. The hydrochloride salt form enhances aqueous solubility. The compound is stable in lyophilized form for 36 months and in solution at -20degC for 1 month. Detailed PK parameters such as half-life, Cmax, and AUC have been determined in preclinical studies.

Toxicological data for Voruciclib hydrochloride have been evaluated in preclinical studies. The compound is generally well-tolerated at therapeutic doses in animal models. As a CDK inhibitor, the compound's toxicity profile is expected to be related to CDK inhibition in normal tissues, particularly in rapidly dividing cells such as bone marrow and gastrointestinal epithelium. Standard toxicity assessments include body weight monitoring, organ histopathology, serum biochemistry, and hematology in animal studies.

[1]. Voruciclib, a clinical stage oral CDK9 inhibitor, represses MCL-1 and sensitizes high-risk Diffuse Large B-cell Lymphoma to BCL2 inhibition. Sci Rep. 2017 Dec 21;7(1):18007.

Voruciclib is currently undergoing clinical trial NCT03547115 (a phase I study of Voruciclib in patients with B-cell malignancies or acute myeloid leukemia). Voruciclib is a cyclin-dependent kinase (CDK) inhibitor with potential antitumor activity. After administration, Voruciclib selectively inhibits cyclin-dependent kinases 4 (CDK4) and 6 (CDK6). This inhibits phosphorylation of early G1 phase retinoblastoma (Rb) proteins, thereby preventing CDK-mediated G1-S phase transition and leading to cell cycle arrest. This inhibits DNA replication and reduces tumor cell proliferation. CDK4 and 6 are serine/threonine kinases upregulated in various tumor cell types and play a crucial role in the regulation of cell cycle progression. Aberrant regulation of BCL-2 family members can allow tumors to evade apoptosis and develop chemotherapy resistance. BCL-2 and its functionally redundant counterpart MCL-1 are frequently overexpressed in high-risk diffuse large B-cell lymphoma (DLBCL). While the BH3 mimic venetoclax has been clinically proven to inhibit BCL-2, its antitumor efficacy is limited due to compensatory induction of MCL-1. Vorucilib, a clinical-stage CDK-selective inhibitor with high oral bioavailability, effectively blocks the transcriptional regulator of MCL-1, CDK9. This study demonstrates that voruciclib inhibits MCL-1 protein expression in a preclinical model of DLBCL. In vivo, the combination of voruciclib and venetoclax resulted in model-dependent tumor cell apoptosis and tumor growth inhibition. The strongest efficacy was observed in two models representing high-risk activated B cells (ABC) DLBCL, while no efficacy was observed in a third ABC model, and moderate efficacy was observed in two germinal center B-cell-like (GCB) DLBCL models. Given the range of responses, we demonstrate that CIVO (a multi-tumor microdose technique) represents a viable functional precision medicine approach that can differentiate between patients who respond to and do not respond to BCL-2/MCL-1 targeted therapy. These findings suggest that the combination therapy of voruciclib and venetoclax holds promise as a novel, entirely oral combination therapy for the treatment of a subset of high-risk DLBCL patients. [1]

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Voruciclib hydrochloride is an orally active and selective CDK inhibitor with Ki values of 0.626-9.1 nM. It potently blocks CDK9, the transcriptional regulator of MCL-1. The compound has been investigated as a potential treatment for various cancers, including breast cancer, mantle cell lymphoma, and acute myeloid leukemia. It is not an FDA-approved drug but has been studied in clinical trials. The compound is available in high purity (≥98%) and is typically stored at -20degC.

C₂₂H₂₀CL₂F₃NO₅

506.30

505.067

1000023-05-1

Voruciclib;1000023-04-0;(2S,3R)-Voruciclib hydrochloride;rel-(2S,3R)-Voruciclib;1253731-24-6; 1000023-04-0; 2505206-37-9 (malonate)

67409218

Typically exists as Light yellow to yellow solid at room temperature

5.063

4

9

3

33

750

2

ClC1C=C(C(F)(F)F)C=CC=1C1=CC(C2=C(C=C(C(=C2O1)[C@@H]1CCN(C)[C@H]1CO)O)O)=O.Cl

QCWRANLELLMJSH-OJMBIDBESA-N

InChI=1S/C22H19ClF3NO5.ClH/c1-27-5-4-12(14(27)9-28)19-15(29)7-16(30)20-17(31)8-18(32-21(19)20)11-3-2-10(6-13(11)23)22(24,25)26;/h2-3,6-8,12,14,28-30H,4-5,9H2,1H3;1H/t12-,14+;/m1./s1

2-[2-chloro-4-(trifluoromethyl)phenyl]-5,7-dihydroxy-8-[(2R,3S)-2-(hydroxymethyl)-1-methylpyrrolidin-3-yl]chromen-4-one;hydrochloride

Voruciclib hydrochloride; 1000023-05-1; Voruciclib (hydrochloride); UNII-8BEP29W01U; 8BEP29W01U; 2-[2-chloro-4-(trifluoromethyl)phenyl]-5,7-dihydroxy-8-[(2R,3S)-2-(hydroxymethyl)-1-methylpyrrolidin-3-yl]chromen-4-one;hydrochloride; 4H-1-Benzopyran-4-one, 2-(2-chloro-4-(trifluoromethyl)phenyl)-5,7-dihydroxy-8-((2R,3S)-2-(hydroxymethyl)-1-methyl-3-pyrrolidinyl)-, hydrochloride (1:1); 4H-1-Benzopyran-4-one, 2-[2-chloro-4-(trifluoromethyl)phenyl]-5,7-dihydroxy-8-[(2R,3S)-2-(hydroxymethyl)-1-methyl-3-pyrrolidinyl]-, hydrochloride (1:1);

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

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

DMSO : ≥ 250 mg/mL (~493.78 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (4.11 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.08 mg/mL (4.11 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
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.

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Solubility in Formulation 3: ≥ 2.08 mg/mL (4.11 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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