ATR 7 nM (IC50)

Elimusertib hydrochloride potently inhibits the proliferation of a broad spectrum of human tumor cell lines with a median IC50 of 78 nM[1]. Elimusertib hydrochloride potently suppresses hydroxyurea-induced H2AX phosphorylation (IC50: 36 nM)[1]. Elimusertib hydrochloride shows good selectivity against mTOR (ratio of IC50 values: mTOR/ATR 61)[3]. Elimusertib hydrochloride reveals high selectivity against other related kinases, such as DNA-PK (IC50: 332 nM), ATM (IC50: 1420 nM), and PI3K ( IC50: 3270 nM)[3]. Elimusertib hydrochloride has potent antiproliferative activity against various cancer cell lines in vitro, 25 for example in the CRC cell lines HT-29 (IC50: 160 nM) and LoVo (IC50: 71 nM), and in the B-cell lymphoma cell line SU-DHL-8 (IC50: 9 nM)[3].

Elimusertib hydrochloride shows potent anti-tumor efficacy in monotherapy in a variety of xenograft models of ovarian and colorectal cancer, and causes complete tumor remission in mantle cell lymphoma models[2]. Elimusertib hydrochloride (50 mg/kg; p.o.; b.i.d.; 3 days on/4 days off; for 11 days) exhibits strong antitumor efficacy in the ATM-mutated SU-DHL-8 (ATM K1964E) human GCB-DLBCL cell line derived xenograft model in mice[3]. Elimusertib hydrochloride (20 mg/kg, and 10 mg/kg from day 14; p.o.; daily; 2 days on/5 days off; for 42 days) in combination with Carboplatin (40 mg/kg; i.p.; daily; 1 day on/6 days off) results in synergistic antitumor activity in the platinum-resistant ATM protein low expressing CR5038 human CRC PDX model in NOD/SCID mice[3]. Elimusertib hydrochloride exhibits moderate oral bioavailability (rat 87%, dog 51%) following oral administration (rat and dog 0.6-1 mg/kg)[3]. Elimusertib hydrochloride exhibits terminal elimination half-lives (mouse 0.17 h, rat 1.3 and, dog 1.0 h) due to plasma clearance (3.5, 1.2, and 0.79 L/h/kg respectively) following intravenous administration (mouse, rat and dog 0.3-0.5 mg/kg)[3].

Animal/Disease Models:Female C.B-17 SCID mice, SU-DHL-8 GCB-DLBCL xenograft model[3]
Doses: 50 mg/kg
Route of Administration: Oral administration, b.i.d., 3 days on/4 days off, for 11 days
Experimental Results: Inhibited tumor area.

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In vivo studies in CDX models [2]
The in vivo antitumor efficacy and tolerability of Elimusertib (BAY1895344) as monotherapy/combination therapy were evaluated in CDX subcutaneous or orthotopic xenograft models in mice. Monotherapy experiments were performed in GRANTA-519 (in female SCID beige mice), REC-1 (in female C.B-17 SCID mice), PC-3 (in male NMRI nude mice), LOVO, and A2780 (both in female NMRI nude mice) models treated with BAY 1895344 at 50 mg/kg [all models; twice daily, 3 days on/4 days off (3on/4off), per os/orally] or at 3, 10, or 30 mg/kg (GRANTA-519; twice daily, 3on/4off, per os/orally), ibrutinib (REC-1; 20 mg/kg, once daily, per os/orally), AZD6738 (GRANTA-519, REC-1; 50 mg/kg, once daily, per os/orally), M6620 (GRANTA-519 and REC-1; 100 mg/kg, once daily, per os/orally), or 5-FU (LOVO; 50 mg/kg, once weekly, intraperitoneally). The combination of BAY 1895344 at 10 or 20 mg/kg [once daily, 2 days on/5 days off (2on/5off), per os/orally.] or 50 mg/kg (twice daily, 3on/4off, per os/orally) and carboplatin (50 mg/kg, once weekly, intraperitoneally) was investigated in IGROV-1 tumor–bearing female nude (nu/nu) mice. The combination of 20 or 50 mg/kg BAY 1895344 (twice daily, 2on/5off, per os/orally) and EBRT (5 Gy, 7.7 minutes, once daily on days 12 and 27) was investigated in LOVO tumor–bearing female NMRI nude mice. Combination therapy experiments with 20 or 50 mg/kg BAY 1895344 (twice daily, 3on/4off, per os/orally) and 20 or 50 mg/kg olaparib (once daily, intraperitoneally) were performed in MDA-MB-436 and 22Rv1 models in female NOD/SCID and male SCID mice, respectively. Combination experiments with 20 mg/kg BAY 1895344 (twice daily, 3on/4off, per os/orally) and 100 mg/kg darolutamide (once daily, per os/orally) were performed in the hormone-dependent LAPC-4 prostate cancer model in male C.B-17 SCID mice. Castrated mice served here as a control. For a triple combination treatment, mice received EBRT (5 Gy, every 7 days twice) in addition to treatment with BAY 1895344 and darolutamide.
To elucidate the in vivo mode of action of Elimusertib (BAY1895344), ATR and H2AX phosphorylation was determined in lysed GRANTA-519 xenograft tumor samples. For the quantification of circulating ATRis, plasma samples were taken from mice and measured by LC-MS/MS.

[1]. Abstract 983: Identification of potent, highly selective and orally available ATR inhibitor BAY 1895344 with favorable PK properties and promising efficacy in monotherapy and combination in preclinical tumor models. Cancer Resea

[2]. Abstract 836: ATR inhibitor BAY 1895344 shows potent anti-tumor efficacy in monotherapy and strong combination potential with the targeted alpha therapy Radium-223 dichloride in preclinical tumor models. Cancer Research. July

[3]. Damage Incorporated: Discovery of the Potent, Highly Selective, Orally Available ATR Inhibitor BAY 1895344 with Favorable Pharmacokinetic Properties and Promising Efficacy in Monotherapy and in Combination Treatments in Preclinical

Elimusertib is an orally available ataxia telangiectasia and Rad3-related (ATR)-specific kinase inhibitor, with potential antineoplastic activity. Upon oral administration, elimusertib selectively binds to and inhibits the activity of ATR, which prevents ATR-mediated signaling. This inhibits DNA damage checkpoint activation, disrupts DNA damage repair and induces apoptosis in ATR-overexpressing tumor cells. ATR, a serine/threonine protein kinase upregulated in a variety of cancer cell types, plays a key role in DNA repair, cell cycle progression and cell survival.

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The integrity of the genome of eukaryotic cells is secured by complex signaling pathways, known as DNA damage response (DDR). Recognition of DNA damage activates DDR pathways resulting in cell cycle arrest, suppression of general translation, induction of DNA repair, cell survival or even cell death. Proteins that directly recognize aberrant DNA structures recruit and activate kinases of the DDR pathway, such as ATR (ataxia telangiectasia and Rad3-related). ATR responds to a broad spectrum of DNA damage, including double-strand breaks (DSB) and lesions derived from interference with DNA replication as well as increased replication stress (e.g. in oncogene-driven tumor cells). Therefore, inhibition of ATR kinase activity could be the basis for a novel anti-cancer therapy in tumors with increased DNA damage, deficiency in DNA damage repair or replication stress. Herein we report the identification of the potent, highly selective and orally available ATR inhibitor BAY 1895344 by a collaborative effort involving medicinal chemistry, pharmacology, DMPK and computational chemistry. The chemical structures of lead compound BAY-937 and clinical candidate BAY 1895344 as well as the main SAR trends within this novel class of naphthyridine derivatives will be disclosed for the first time. The novel lead compound BAY-937 revealed promising inhibition of ATR (IC50 = 78 nM) and high kinase selectivity in vitro. In cellular mechanistic assays BAY-937 inhibited hydroxyurea-induced H2AX phosphorylation (IC50 = 380 nM) demonstrating the anticipated mode of action. Moreover, BAY-937 was shown to inhibit proliferation of a variety of tumor cell lines with low- to sub-micromolar IC50 values. In initial xenograft studies, BAY-937 revealed moderate activity in monotherapy and in combination with cis-platin. However, BAY-937 also revealed low aqueous solubility, low bioavailability (rat) and activity in the hERG patch clamp assay. Extensive lead optimization efforts led to the identification of the novel, orally available ATR inhibitor BAY 1895344. In vitro, BAY 1895344 was shown to be a very potent and highly selective ATR inhibitor (IC50 = 7 nM), which potently inhibits proliferation of a broad spectrum of human tumor cell lines (median IC50 = 78 nM). In cellular mechanistic assays BAY 1895344 potently inhibited hydroxyurea-induced H2AX phosphorylation (IC50 = 36 nM). Moreover, BAY 1895344 revealed significantly improved aqueous solubility, bioavailability across species and no activity in the hERG patch-clamp assay. BAY 1895344 also demonstrated very promising efficacy in monotherapy in DNA damage deficient tumor models as well as combination treatment with DNA damage inducing therapies. The start of clinical investigation of BAY 1895344 is planned for early 2017. [1]

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The DNA damage response (DDR) secures the integrity of the genome of eukaryotic cells. DDR deficiencies can promote tumorigenesis but concurrently may increase dependence on alternative repair pathways. The ataxia telangiectasia and Rad3-related (ATR) kinase plays a central role in the DDR by activating essential signaling pathways of DNA damage repair. Here, we studied the effect of the novel selective ATR kinase inhibitor BAY 1895344 on tumor cell growth and viability. Potent antiproliferative activity was demonstrated in a broad spectrum of human tumor cell lines. BAY 1895344 exhibited strong monotherapy efficacy in cancer xenograft models that carry DNA damage repair deficiencies. The combination of BAY 1895344 with DNA damage-inducing chemotherapy or external beam radiotherapy (EBRT) showed synergistic antitumor activity. Combination treatment with BAY 1895344 and DDR inhibitors achieved strong synergistic antiproliferative activity in vitro, and combined inhibition of ATR and PARP signaling using olaparib demonstrated synergistic antitumor activity in vivo Furthermore, the combination of BAY 1895344 with the novel, nonsteroidal androgen receptor antagonist darolutamide resulted in significantly improved antitumor efficacy compared with respective single-agent treatments in hormone-dependent prostate cancer, and addition of EBRT resulted in even further enhanced antitumor efficacy. Thus, the ATR inhibitor BAY 1895344 may provide new therapeutic options for the treatment of cancers with certain DDR deficiencies in monotherapy and in combination with DNA damage-inducing or DNA repair-compromising cancer therapies by improving their efficacy.[2]

C20H22CLN7O

411.89

Solid powder

BAY 1895344 hydrochloride

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 : 50 mg/mL (121.39 mM; with sonication)
H2O : 50 mg/mL (121.39 mM; with sonication)

Solubility in Formulation 1: ≥ 2.08 mg/mL (5.05 mM)(Saturation unknown) in 10% DMSO 40% PEG300 5% Tween-80 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, add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix well; then add 50 μL Tween-80 to the above system and mix well; then add 450 μL saline to make up 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 (5.05 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, add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD in saline and mix well.
*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 (5.05 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, add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL corn oil and mix well. For the following dissolution schemes, please prepare the working solution directly. It is recommended to prepare it as soon as possible and use it up in a short period of time. The percentage shown in front of the following solvents refers to the volume percentage of the solvent in the final solution you prepare; if precipitation or precipitation occurs during the preparation process, heating and/or ultrasound can be used to assist dissolution.

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