CDK4 (IC50 = 1.2 nM); CDK6 (IC50 = 1.3 nM)

The metabolite M2 (LSN2839567) of Abemaciclib binds to tethering proteins in humans, dogs, and gold at a rate of 83-92%, whereas Abemaciclib binds at a rate of 95-99% [2]. The most notable (active and significant) transporter in humans is abelacil metabolite M2 [2].

[1]. Abstract 2830: The major human metabolites of abemaciclib are inhibitors of CDK4 and CDK6. Cancer Research. July 2016, 76 (14).

[2]. CHMP. Assessment report Verzenios. 26 July 2018 EMA/551438/2018.

Abemaciclib (LY2835219) is an ATP-competitive inhibitor of cyclin dependent kinases 4 and 6 (CDK4 and CDK6) which is currently undergoing clinical evaluation for the treatment of breast and lung cancers. A radiolabeled disposition study following a single 150-mg oral dose of [14C]LY2835219 in healthy subjects indicated that in plasma, in addition to parent drug, the presence of 5 metabolites denoted as M1, M2, M18, M20 and M22. Abemaciclib (34%), M20 (26%), M2 (13%), and M18 (5%) constituted the majority of the plasma exposure. This study investigated the in vitro biological activity of these human circulating metabolites, with the exception of the trace metabolite, M1, and compared their potencies with the parent drug abemaciclib. Specifically non-small cell lung cancer (NSCLC) cells, colorectal cancer (CRC) cells and breast cancer cell lines were evaluated for growth inhibition, cell cycle inhibition and biomarker expression following treatment with abemaciclib and the metabolites. The metabolites were also profiled and compared to abemaciclib for inhibition of CDK4, CDK6, CDK1, and CDK9 in cell-free biochemical kinase assays. The IC50 values for the inhibition of CDK4 and CDK6, for metabolites M2, M18, and M20, but not M22, were between 1 and 3 nM and were nearly equivalent in potency to abemaciclib. Likewise, metabolites M2, M20, and M18 inhibited cell growth and cell cycle progression in a concentration-dependent manner that was consistent with the inhibition of CDK4 and CDK6 since these outcomes correlated with the concentration-dependent inhibition of various biomarkers such a phospho-serine 780-Rb (pRb), topoisomerase II-alpha (Topo IIα), and phospho-serine 10-histone H3 (pHH3). In this regard, metabolites M2 and M20 showed potencies nearly identical with abemaciclib in the cancer cell lines evaluated, whereas depending on the endpoint measured, the potency of M18 was approximately 3-20-fold lower than abemaciclib. M22 showed the least potency for growth inhibition and little or no inhibition of biomarker expression or cell cycle progression at concentrations below 2 μM. Although the cell-free kinase assays showed that like abemaciclib, M2, M18, and M20 had potential to inhibit CDK9, no measurable inhibition of CDK9 by any of these compounds was observed in cancer cells, indicating that the primary targets driving cell cycle inhibition for these metabolites in cancer cells were CDK4 and CDK6 and not CDK9. Studies with abemaciclib, M2 or M20 in breast cancer cells showed that all 3 compounds induced senescence in addition to growth inhibition following 6-8 days of treatment at 200 and 500 nM. In total the results indicated that the major human metabolites of abemaciclib, M2 and M20, are effective inhibitors of CDK4 and CDK6 that are remarkably similar to abemaciclib in regards to their effects in cancer cells on growth, senescence, and other phenotypic responses.[1]

C25H28F2N8

478.540230751038

478.24

1231930-57-6

Abemaciclib metabolite M2-d6

59376686

Light yellow to yellow solid powder

3

2

9

6

35

680

0

FC1=CC(C2C(=CN=C(N=2)NC2=CC=C(C=N2)CN2CCNCC2)F)=CC2=C1N=C(C)N2C(C)C

IXGZDCRFGCEEBU-UHFFFAOYSA-N

InChI=1S/C25H28F2N8/c1-15(2)35-16(3)31-24-19(26)10-18(11-21(24)35)23-20(27)13-30-25(33-23)32-22-5-4-17(12-29-22)14-34-8-6-28-7-9-34/h4-5,10-13,15,28H,6-9,14H2,1-3H3,(H,29,30,32,33)

5-fluoro-4-(7-fluoro-2-methyl-3-propan-2-ylbenzimidazol-5-yl)-N-[5-(piperazin-1-ylmethyl)pyridin-2-yl]pyrimidin-2-amine

1231930-57-6; Abemaciclib Metabolites M2; Abemaciclib metabolite M2; 5-Fluoro-4-(4-fluoro-1-isopropyl-2-methyl-1H-benzo[d]imidazol-6-yl)-N-[5-(1-piperazinylmethyl)-2-pyridyl]pyrimidin-2-amine; 5-fluoro-4-(7-fluoro-2-methyl-3-propan-2-ylbenzimidazol-5-yl)-N-[5-(piperazin-1-ylmethyl)pyridin-2-yl]pyrimidin-2-amine; Des-Et-Abemaciclib; MFCD32067988; LSN2839567;

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)

DMSO : ~2 mg/mL (~4.18 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.22 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 25.0 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.

---

Solubility in Formulation 2: ≥ 2.5 mg/mL (5.22 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 25.0 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.

---

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