CDK4 (IC50 = 2 nM); CDK6 (IC50 = 10 nM); Cdk4/cyclin D1 (IC50 = 2 nM); CDK6/cyclinD1 (IC50 = 10 nM); CDK9/cyclinT1 (IC50 = 57 nM); CDK5/p35 (IC50 = 287 nM); Cdk5/p25 (IC50 = 355 nM); CDK2/cyclinE (IC50 = 504 nM); CDK7/Mat1/cyclinH1 (IC50 = 3910 nM); CDK1/cyclinB1 (IC50 = 1627 nM); PIM1 (IC50 = 39 nM); PIM2 (IC50 = 3400 nM); HIPK2 (IC50 = 31 nM); DYRK2 (IC50 = 61 nM); CK2 (IC50 = 117 nM); GSK3b (IC50 = 192 nM); JNK3 (IC50 = 389 nM); FLT3 (D835Y) (IC50 = 403 nM); FLT3 (IC50 = 3960 nM); DRAK1 (IC50 = 659 nM)

体外活性：Abemaciclib（以前称为 LY2835219）是一种有效、选择性、口服的 CDK4（细胞周期蛋白依赖性激酶）和 CDK6 双重抑制剂，在无细胞测定中 IC50 分别为 2 nM 和 10 nM。 LY2835219 特异性抑制 CDK4 和 6，从而抑制 G1 早期视网膜母细胞瘤 (Rb) 蛋白磷酸化。抑制 Rb 磷酸化可阻止 CDK 介导的 G1-S 相变，从而将细胞周期阻滞在 G1 期，抑制 DNA 合成并抑制癌细胞生长。丝氨酸/苏氨酸激酶 CDK4/6 的过度表达可导致细胞周期失调，如某些类型的癌症中所见。激酶测定：将细胞 (5 × 103) 铺在 96 孔板中。第二天将细胞处理 24 至 48 小时，然后根据制造商的说明和发光板读数器，通过 Caspase-Glo-3/7 测定法评估 caspase-3 活性。细胞测定：将细胞接种到 96 孔板中，使其粘附过夜，并用 DMSO 对照 (0.1% v/v) 或指定化合物处理 72 小时。根据制造商的说明，使用细胞计数试剂盒测定细胞活力和增殖。使用 CompuSyn 确定 LY2835219 和 mTOR 抑制剂之间的相互作用。组合指数 (CI) 值为 1 表示药物相互作用相加，而 CI < 1 表示协同作用，CI > 1 表示拮抗作用。

LY2835219 使 BBB 流出饱和，未结合血浆 IC50 约为 95 nM。 LY2835219-MsOH 在大脑中的剂量百分比为 0.5–3.9%。在皮下和颅内人胶质母细胞瘤模型 (U87MG) 中，LY2835219-MsOH 作为单一药物以及与替莫唑胺联合使用，均以剂量依赖性方式抑制肿瘤生长。

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观察到Abemaciclib/阿贝马昔利单药可增强ID8小鼠卵巢癌模型的免疫浸润，尤其是CD8+ T细胞和B细胞的浸润。免疫表型分析表明，abemaciclib在肿瘤微环境中诱导了促炎免疫反应。PCR阵列分析显示，abemaciclib治疗的ID8肿瘤中存在th1极化的细胞因子谱。体外研究表明，abemaciclib处理的ID8细胞比对照组分泌更多的CXCL10和CXCL13，从而募集更多的淋巴细胞。联合治疗对肿瘤的控制优于单药治疗，CD8+和CD4+ T细胞活性较单药治疗进一步增强。abemaciclib联合抗pd -1治疗的协同抗肿瘤作用依赖于CD8+ T细胞和B细胞。结论:CDK4/6i与抗pd -1抗体联合治疗可提高抗pd -1治疗的疗效，对治疗免疫浸润不良的卵巢癌有很大的希望[3]。

LY2835219 (abemaciclib)是由礼来公司研究实验室的科学家通过化合物和生化筛选鉴定出来的，并因其生物活性和对CDK4/ cyclin D1复合物(IC50 =2 nmol/L)和CDK6/cyclin D1复合物(IC50 =10 nmol/L)的高度选择性抑制而被选中，在纳摩尔范围内对其他CDK/cyclin复合物或细胞周期相关激酶没有活性，除了CDK9的IC50至少高出5倍(图2)23该化合物被证明是CDK4和CDK6的atp结合域的竞争性抑制剂，对CDK4的抑制作用是对CDK6的14倍。与palbociclib和ribociclib相比，abemaciclib对复合物CDK4/cyclin D1具有更高的选择性，IC50值比其他两种化合物低5倍[1]。

采用聚对苯二甲酸乙二醇酯悬挂细胞培养片(5.0 μm)在24孔板上观察CD8+ T细胞和B细胞的体外迁移。底室分别取经abemaciclib或pbs处理的ID8细胞上清液600 μL作为化学引诱剂。利用阻断抗体进行transwell实验时，将30 μg/mL抗cxcl10或40 μg/mL抗cxcl13添加到含有abemaciclib处理的ID8细胞上清的下腔中。用大鼠IgG或山羊IgG作为同型对照抗体。上腔内注入100 μL新鲜分离的CD8+ T细胞或B细胞。在标准5% CO2培养箱中37°C孵育3小时后，用血细胞计计数迁移到下腔的细胞。[3]

Female C57BL/6 mice
50 mg/kg
i.p.

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In this study, researchers first assessed the antitumor efficacy of abemaciclib, an FDA-approved CDK4/6i, in a syngeneic murine ovarian cancer model. Then, immunohistochemistry, immunofluorescence and flow cytometry were performed to evaluate the number, proportion, and activity of tumor-infiltrating lymphocytes. Cytokine and chemokine production was detected both in vivo and in vitro by PCR array analysis and cytokine antibody arrays. The treatment efficacy of combined abemaciclib and anti-PD-1 therapy was evaluated in vivo, and CD8+ and CD4+ T cell activities were analyzed using flow cytometry. Lastly, the requirement for both CD8+ T cells and B cells in combination treatment was evaluated in vivo, and potential cellular mechanisms were further analyzed by flow cytometry. [3]

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Mouse cytokine and chemokine array[3]
ID8 cells seeded at equal numbers were cultured in complete medium for 24 hours, washed twice with PBS and cultured in FBS-free DMEM plus 10 µmol/L abemaciclib or PBS for 24 hours. Then, the supernatants were collected and processed for mouse cytokine array analysis according to the manufacturer's protocols. Membranes were scanned using an LAS-500 imager. Relative cytokine levels were obtained by grayscale analysis using ImageJ.[3]

Absorption
The plasma concentration of the drug increases in a dose-proportional manner. Following a single oral dose administration of 200 mg abemaciclib, the mean peak plasma concentration (Cmax) of 158 ng/mL is reached after 6 hours. The median time to reach maximum plasma concentration (Tmax) ranges from 4-6 hours following an oral administration of abemaciclib over a range of 50–275 mg, but may range up to 24 hours. The absolute bioavailability of the drug is reported to be 45%.

Route of Elimination
Following a single oral dose of 150mg radiolabeled abemaciclib, approximately 81% of the total dose was recovered in feces while 3% of the dose was detected in urine. The majority of the drug is exceted as metabolites.

Volume of Distribution
The geometric mean systemic volume of distribution is approximately 690.3 L (49% CV).

Clearance
The geometric mean hepatic clearance (CL) of abemaciclib in patients was 26.0 L/h (51% CV).

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Metabolism / Metabolites
Abemaciclib mainly undergoes hepatic metabolism mediated by CYP3A4. The major metabolite formed is N-desethylabemaciclib (M2), while other metabolites hydroxyabemaciclib (M20), hydroxy-N-desethylabemaciclib (M18), and an oxidative metabolite (M1) are also formed. M2, M18, and M20 are equipotent to abemaciclib and their AUCs accounted for 25%, 13%, and 26% of the total circulating analytes in plasma, respectively.

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Biological Half-Life
The mean plasma elimination half-life for abemaciclib in patients was 18.3 hours (72% CV).

Hepatotoxicity
In the large clinical trials, adverse events were common and led to dose reductions in up to one-half of patients and discontinuation in 9%. In preregistration clinical trials, ALT elevations occurred in 31% to 41% of abemaciclib treated subjects which were above 5 times the ULN in 3% to 5%. In one study, several recipients developed clinically apparent liver injury with jaundice and one recipient died of hepatic failure, but these outcomes were considered to be unrelated to abemaciclib therapy. Thus, there were no cases of clinically apparent liver injury that could be attributed to abemaciclib therapy during prelicensure studies. Since the approval and more widescale use of abemaciclib, there have been no published reports of its hepatotoxicity. Nevertheless, the high rate of serum enzyme elevations during therapy and the similarity of abemaciclib to ribociclib and palbociclib makes it an agent that should be suspected of causing rare instances of clinically significant liver injury.
Likelihood score: E* (unproved but suspected, rare cause of clinically apparent liver injury).

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Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
No information is available on the clinical use of abemaciclib during breastfeeding. Because abemaciclib and its metabolites are over 90% bound to plasma proteins, the amount in milk is likely to be low. However, the manufacturer recommends that breastfeeding be discontinued during abemaciclib therapy and for 3 weeks after the final dose.

◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.

◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.

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Protein Binding
According to in vitro models using animal brain tissues, the protein binding of abemaciclib is approximately 95-98%. While abemaciclib demonstrated *in vitro* binding to serum albumin, alpha-1-acid glycoprotein and other human plasma proteins in a concentration-depedent manner, its major metabolites are also shown to bind to plasms proteins as well. The approximate bound fractions of M2, M18 and M20 are 93.4%, 96.8% and 97.8%, respectively.

[1]. Drug Des Devel Ther . 2018 Feb 16:12:321-330.

[2]. Nat Med . 2021 Feb;27(2):289-300.

[3]. Theranostics . 2020 Aug 25;10(23):10619-10633.

Abemaciclib Mesylate is the mesylate salt of abemaciclib, an orally available cyclin-dependent kinase (CDK) inhibitor that targets the cyclin D1-CDK4 and cyclin D3-CDK6 cell cycle pathway, with potential antineoplastic activity. Abemaciclib specifically inhibits CDK4 and 6, thereby inhibiting retinoblastoma (Rb) protein phosphorylation in early G1. Inhibition of Rb phosphorylation prevents CDK-mediated G1-S phase transition, thereby arresting the cell cycle in the G1 phase, suppressing DNA synthesis and inhibiting cancer cell growth. Overexpression of the serine/threonine kinases CDK4/6, as seen in certain types of cancer, causes cell cycle deregulation.

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Great progress has been made in the field of tumor immunotherapy in the past decade. However, the therapeutic effects of immune checkpoint blockade (ICB) against ovarian cancer are still limited. Recently, an inhibitor of cyclin-dependent kinases 4 and 6 (CDK4/6i) has been reported to enhance antitumor immunity in preclinical models. The combined use of CDK4/6i and ICB may be beneficial, but the effects of CDK4/6is on the tumor immune microenvironment and whether they can synergize with ICB in treating ovarian cancer remain unknown. Methods: In this study, we first assessed the antitumor efficacy of abemaciclib, an FDA-approved CDK4/6i, in a syngeneic murine ovarian cancer model. Then, immunohistochemistry, immunofluorescence and flow cytometry were performed to evaluate the number, proportion, and activity of tumor-infiltrating lymphocytes. Cytokine and chemokine production was detected both in vivo and in vitro by PCR array analysis and cytokine antibody arrays. The treatment efficacy of combined abemaciclib and anti-PD-1 therapy was evaluated in vivo, and CD8+ and CD4+ T cell activities were analyzed using flow cytometry. Lastly, the requirement for both CD8+ T cells and B cells in combination treatment was evaluated in vivo, and potential cellular mechanisms were further analyzed by flow cytometry. Results: We observed that abemaciclib monotherapy could enhance immune infiltration, especially CD8+ T cell and B cell infiltration, in the ID8 murine ovarian cancer model. Immunophenotyping analysis showed that abemaciclib induced a proinflammatory immune response in the tumor microenvironment. PCR array analysis suggested the presence of a Th1-polarized cytokine profile in abemaciclib-treated ID8 tumors. In vitro studies showed that abemaciclib-treated ID8 cells secreted more CXCL10 and CXCL13, thus recruiting more lymphocytes than control groups. Combination treatment achieved better tumor control than monotherapy, and the activities of CD8+ and CD4+ T cells were further enhanced when compared with monotherapy. The synergistic antitumor effects of combined abemaciclib and anti-PD-1 therapy depended on both CD8+ T cells and B cells. Conclusion: These findings suggest that combined treatment with CDK4/6i and anti-PD-1 antibody could improve the efficacy of anti-PD-1 therapy and hold great promise for the treatment of poorly immune-infiltrated ovarian cancer.[3]

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Although early breast cancer (BC) is highly curable, advanced or metastatic disease poses numerous challenges in terms of medical management and treatment decisions and is associated with significantly worse prognosis. Among the new targeted agents, anticancer drugs exploiting the cell-cycle machinery have shown great potential in preclinical studies. CDK4/6 inhibitors target the cyclin D/CDK/retinoblastoma signaling pathway, inducing cell-cycle arrest, reduced cell viability and tumor shrinking. As the cyclin D/CDK complex is activated downstream of estrogen signaling, the combination of CDK4/6 inhibitors with standard endocrine therapies represents a rational approach to elicit synergic antitumor activity in hormone receptor-positive BC. The results of clinical trials have indeed confirmed the superiority of the combination of CDK4/6 inhibitors plus endocrine therapies over endocrine therapy alone. Currently approved are three compounds that exhibit similar structural characteristics as well as biological and clinical activities. Abemaciclib is the latest CDK4/6 inhibitor approved by the US Food and Drug Administration (FDA) in view of the results of the MONARCH 1 and 2 trials. Further trials are ongoing as other important questions await response. In this review, we focus on abemaciclib to examine preclinical and clinical results, describing current therapeutic indications, open questions and ongoing clinical trials.[1]

C28H36F2N8O3S

602.7

602.259

C, 55.80; H, 6.02; F, 6.30; N, 18.59; O, 7.96; S, 5.32

1231930-82-7

Abemaciclib;1231929-97-7

71576678

White to yellow solid powder

5.47

137.75

2

12

7

42

815

0

CC(N1C2=CC(C3=NC(NC4=NC=C(CN5CCN(CC)CC5)C=C4)=NC=C3F)=CC(F)=C2N=C1C)C.CS(=O)(O)=O

NCJPFQPEVDHJAZ-UHFFFAOYSA-N

InChI=1S/C27H32F2N8.CH4O3S/c1-5-35-8-10-36(11-9-35)16-19-6-7-24(30-14-19)33-27-31-15-22(29)25(34-27)20-12-21(28)26-23(13-20)37(17(2)3)18(4)32-26;1-5(2,3)4/h6-7,12-15,17H,5,8-11,16H2,1-4H3,(H,30,31,33,34);1H3,(H,2,3,4)

N-[5-[(4-ethylpiperazin-1-yl)methyl]pyridin-2-yl]-5-fluoro-4-(7-fluoro-2-methyl-3-propan-2-ylbenzimidazol-5-yl)pyrimidin-2-amine;methanesulfonic acid

Abemaciclib; LY-2835219 mesylate; LY2835219; Abemaciclib methanesulfonate; N-(5-((4-ethylpiperazin-1-yl)methyl)pyridin-2-yl)-5-fluoro-4-(4-fluoro-1-isopropyl-2-methyl-1H-benzo[d]imidazol-6-yl)pyrimidin-2-amine methanesulfonate; LY2835219 Mesylate; LY-2835219 methanesulfonate; Abemaciclib (methanesulfonate); KKT462Q807; LY 2835219; Abemaciclib mesylate

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

注意： 请将本产品存放在密封且受保护的环境中，避免吸湿/受潮。

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

配方 1 中的溶解度: ≥ 2.5 mg/mL (4.15 mM) (饱和度未知) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将100 μL 25.0 mg/mL澄清DMSO储备液加入到400 μL PEG300中，混匀；然后向上述溶液中加入50 μL Tween-80，混匀；加入450 μL生理盐水定容至1 mL。
*生理盐水的制备：将 0.9 g 氯化钠溶解在 100 mL ddH₂O中，得到澄清溶液。

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配方 2 中的溶解度: 2.5 mg/mL (4.15 mM) (饱和度未知) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (这些助溶剂从左到右依次添加，逐一添加), 悬浊液; 超声助溶。
例如，若需制备1 mL的工作液，可将 100 μL 25.0 mg/mL澄清DMSO储备液加入900 μL 20% SBE-β-CD生理盐水溶液中，混匀。
*20% SBE-β-CD 生理盐水溶液的制备（4°C，1 周）：将 2 g SBE-β-CD 溶解于 10 mL 生理盐水中，得到澄清溶液。

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配方 3 中的溶解度: ≥ 2.5 mg/mL (4.15 mM) (饱和度未知) in 10% DMSO + 90% Corn Oil (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将 100 μL 25.0 mg/mL 澄清 DMSO 储备液加入到 900 μL 玉米油中并混合均匀。

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配方 4 中的溶解度: 2 mg/mL (3.32 mM) in 5% DMSO + 40% PEG300 + 5% Tween80 + 50% Saline (这些助溶剂从左到右依次添加，逐一添加), 悬浊液; 超声助溶。
*生理盐水的制备：将 0.9 g 氯化钠溶解在 100 mL ddH₂O中，得到澄清溶液。

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配方 5 中的溶解度: ≥ 2 mg/mL (3.32 mM) (饱和度未知) in 5% DMSO + 95% (20% SBE-β-CD in Saline) (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
*20% SBE-β-CD 生理盐水溶液的制备（4°C，1 周）：将 2 g SBE-β-CD 溶解于 10 mL 生理盐水中，得到澄清溶液。

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配方 6 中的溶解度: Water: 100 mg/mL (~165.9 mM)

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配方 7 中的溶解度: 25 mg/mL (41.48 mM) in PBS (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液; 超声助溶.

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配方 8 中的溶解度: 12.5 mg/mL (20.74 mM) in 0.5% HEC (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液; 超声助溶.

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请根据您的实验动物和给药方式选择适当的溶解配方/方案：
1、请先配制澄清的储备液(如：用DMSO配置50 或 100 mg/mL母液(储备液));
2、取适量母液，按从左到右的顺序依次添加助溶剂，澄清后再加入下一助溶剂。以 下列配方为例说明 (注意此配方只用于说明，并不一定代表此产品 的实际溶解配方):
10% DMSO → 40% PEG300 → 5% Tween-80 → 45% ddH2O (或 saline);
假设最终工作液的体积为 1 mL, 浓度为5 mg/mL: 取 100 μL 50 mg/mL 的澄清 DMSO 储备液加到 400 μL PEG300 中，混合均匀/澄清；向上述体系中加入50 μL Tween-80，混合均匀/澄清；然后继续加入450 μL ddH2O (或 saline)定容至 1 mL；
3、溶剂前显示的百分比是指该溶剂在最终溶液/工作液中的体积所占比例;
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