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IUPAC name 1-(2-{5-[(3-methyloxetan-3-yl)methoxy]-1H-benzimidazol-1-yl}quinolin-8-yl)piperidin-4-amine | |
Other names CP-868,596; AR-868,596-26 | |
Identifiers | |
3D model (JSmol) | |
ChEBI | |
ChEMBL | |
ChemSpider | |
KEGG | |
PubChem CID | |
UNII | |
CompTox Dashboard (EPA) | |
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Properties | |
C26H29N5O2 | |
Molar mass | 443.551 g·mol−1 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Crenolanib besylate (CP-868,596-26 or AR-868,596-26, 4-piperidinamine, 1-[2-[5-[(3-Methyl-3-oxetanyl) methoxy]-1H-benzimidazol-1-yl]- 8-quinolinyl]-, monobenzenesulfonate) is an investigational inhibitor being developed by AROG Pharmaceuticals, LLC. The compound is currently being evaluated for safety and efficacy in clinical trials for various types of cancer, including acute myeloid leukemia (AML), [1] [2] gastrointestinal stromal tumor (GIST), [3] and glioma. [4] Crenolanib is an orally bioavailable benzimidazole that selectively and potently inhibits signaling of wild-type and mutant isoforms of class III receptor tyrosine kinases (RTK) FLT3 (FMS-like Tyrosine Kinase 3), PDGFR α (Platelet-Derived Growth Factor Receptor), and PDGFR β. Unlike most RTK inhibitors, crenolanib is a type I mutant-specific inhibitor that preferentially binds to phosphorylated active kinases with the ‘DFG in’ conformation motif. [5]
Type III Receptor tyrosine kinase, including FLT3, PDGFRα and PDGFRβ, have been directly implicated in the pathogenesis of epithelial, mesenchymal, and hematological malignancies. [6]
Mutations of FLT3 comprise one of the most frequently identified types of genetic alterations in acute myeloid leukemia. [7] [8] Approximately one-third of AML patients present with a mutation in this gene. [9] The majority of these mutations result in constitutive activation of downstream signaling pathways and aberrant cell growth. [7] Mutations in FLT3 have also been reported in acute lymphoblastic leukemia (ALL) [10] and myelodysplastic syndrome (MDS). [11]
Activating mutations in PDGFRA have been detected in 5-12% of Gastrointestinal stromal tumor. [12] Fusion of PDGFRA has been found to be responsible for hematological malignances like hypereosinophilic syndrome. [13] The amplification of chromosome 4q12, the site of the PDGFRA gene[ citation needed ], has been identified in 13-29% of adult gliomas [ citation needed ] and in 29% to 36% of diffuse intrinsic pontine gliomas (DIPG)[ citation needed ], a subset of high-grade gliomas (HGG) in pediatric patients. Activation of PDGFRB, a third member of the type III RTK family, has been implicated in the development of chronic myelomonocytic leukemia due to the fusion of PDGFRB with the TEL gene. [13] Furthermore, PDGFB translocation to the COL1A1 gene locus has been identified to be responsible for dermatofibrosarcoma protuberans (DFSP). [13] In cancer cells, PDGFR promotes tumor development and migration via proto-oncogenic downstream mediators like AKT and MEK [ citation needed ]. In stromal fibroblasts, PDGFRα activation leads to local tissue invasion, production and secretion of VEGF, and elevated intratumoral interstitial pressure[ citation needed ]. In stromal pericytes, PDGFRβ activation mediates vascular stability. [13] Thus, either FLT3 or PDGF/PDGFR pathway is the primary driver of oncogenesis in the above malignancies and can be targeted by crenolanib therapy[ citation needed ].
Crenolanib inhibits both wild type FLT3 and its constitutively active mutations. In vitro studies have shown that crenolanib has low Kd for the FLT3 enzyme with constitutively activating internal tandem duplication (ITD) mutations and tyrosine kinase domain (TKD) mutations, D835H and D835Y, as compared to wild type. Crenolanib tightly binds to FLT3-ITD, FLT3-D835H and FLT3-D835Y with Kd of 0.74 nM, 0.4 nM, and 0.18 nM, respectively. [14] Crenolanib inhibits the phosphorylation of the FLT3-ITD receptor in transfected TF-1 cells and the FLT3-D835Y TKD mutation in transfected Ba/F3 cells at nanomolar IC50 concentrations of 1.3 nM and 8.8 nM, respectively. [15] Immunoblot experiments performed in the Molm14 FLT3-ITD positive cell line show that crenolanib inhibits downstream signaling of FLT3 at a concentration of 10 nM. [15] MTT assay measurements of crenolanib cytotoxicity evaluated in the FLT3-ITD expressing cell lines Molm14 and MV411, showed that crenolanib is toxic at IC50 concentrations of 7 nM and 8 nM, respectively. [15]
Crenolanib has been shown to inhibit PDGFRα with an IC50 of 0.4 ng/mL in porcine aortic epithelial cell lines. In Chinese hamster ovary (CHO) cells expressing PDGFRα, crenolanib inhibited the phosphorylation of wild type PDGFRα at an IC50 of 10 nM. [16] Additionally, crenolanib completely blocked PDGFRα phosphorylation and downstream AKT signaling at a concentration between 0.1 and 1 uM in Ink4a/Arf-/- mouse astrocytes transfected to stably co-express both human PDGFRα and PDGF AA. [17] The lung cancer cell line H1703, which is reported to have amplification of both PDGFRA (4q12) and PDGFC (4q32) genes on chromosome 4, and also overexpress PDGFRα, was sensitive to crenolanib with an IC50 of ~80 nM. [18] In CHO cells expressing an activating exon 18 (D842V) PDGFRα mutation, crenolanib was effective at an IC50 of 6nM and IC90 of 25nM. In addition, crenolanib also inhibited phosphorylation of the double mutants PDGFRα (V561D + D842V and T674I + D842V). [16]
Crenolanib has been shown to inhibit PDGFRβ with an IC50 of 0.8 ng/mL in porcine aortic epithelial cell lines. Crenolanib inhibits the ability of recombinant PDGFRβ to phosphorylate a synthetic tyrosine substrate (poly-glutamic acid-tyrosine), with an IC50 of 0.4 ng/mL. Evaluation of the antitumor activity of crenolanib in a genetically engineered BSG DIPG mouse model showed that it is highly selective for PDGFRβ with an IC50 of 10 nM when measured by BrdU assay and 1.25 uM by MTT assay.
Crenolanib has been shown to have IC50 and Kd values of 67 nM and 78 nM, respectively, for wild type c-KIT in in vitro assays[ citation needed ]. Similar assays show that crenolanib inhibits c-KIT activating mutations D816H and D816V with IC50 concentrations of 5.4 and 2.5 nM, respectively. [14] [ citation needed ] Human bone marrow progenitor cell growth assays showed that crenolanib has modest effects on GM-CSF and BFUE driven colony formation at the IC50 concentration of 20 nM. [15]
Phase I single-agent [19] and Phase Ib combination [20] studies have investigated the clinical pharmacology of crenolanib in patients with cancer. Pharmacokinetic and safety studies of Crenolanib administered alone or in combination with docetaxel with or without axitinib have been completed. Results suggest that Crenolanib is well tolerated as a single agent, and can also be safely combined with docetaxel and axitinib due to their non-overlapping toxicity profiles.
A tyrosine kinase is an enzyme that can transfer a phosphate group from ATP to the tyrosine residues of specific proteins inside a cell. It functions as an "on" or "off" switch in many cellular functions.
The Philadelphia chromosome or Philadelphia translocation (Ph) is a specific genetic abnormality in chromosome 22 of leukemia cancer cells. This chromosome is defective and unusually short because of reciprocal translocation, t(9;22)(q34;q11), of genetic material between chromosome 9 and chromosome 22, and contains a fusion gene called BCR-ABL1. This gene is the ABL1 gene of chromosome 9 juxtaposed onto the breakpoint cluster region BCR gene of chromosome 22, coding for a hybrid protein: a tyrosine kinase signaling protein that is "always on", causing the cell to divide uncontrollably by interrupting the stability of the genome and impairing various signaling pathways governing the cell cycle.
Imatinib, sold under the brand names Gleevec and Glivec (both marketed worldwide by Novartis) among others, is an oral targeted therapy medication used to treat cancer. Imatinib is a small molecule inhibitor targeting multiple tyrosine kinases such as CSF1R, ABL, c-KIT, FLT3, and PDGFR-β. Specifically, it is used for chronic myelogenous leukemia (CML) and acute lymphocytic leukemia (ALL) that are Philadelphia chromosome–positive (Ph+), certain types of gastrointestinal stromal tumors (GIST), hypereosinophilic syndrome (HES), chronic eosinophilic leukemia (CEL), systemic mastocytosis, and myelodysplastic syndrome.
Proto-oncogene c-KIT is the gene encoding the receptor tyrosine kinase protein known as tyrosine-protein kinase KIT, CD117 or mast/stem cell growth factor receptor (SCFR). Multiple transcript variants encoding different isoforms have been found for this gene. KIT was first described by the German biochemist Axel Ullrich in 1987 as the cellular homolog of the feline sarcoma viral oncogene v-kit.
Acute myeloblastic leukemia with maturation (M2) is a subtype of acute myeloid leukemia (AML).
Cluster of differentiation antigen 135 (CD135) also known as fms like tyrosine kinase 3, receptor-type tyrosine-protein kinase FLT3, or fetal liver kinase-2 (Flk2) is a protein that in humans is encoded by the FLT3 gene. FLT3 is a cytokine receptor which belongs to the receptor tyrosine kinase class III. CD135 is the receptor for the cytokine Flt3 ligand (FLT3L).
Fibroblast growth factor receptor 1 (FGFR1), also known as basic fibroblast growth factor receptor 1, fms-related tyrosine kinase-2 / Pfeiffer syndrome, and CD331, is a receptor tyrosine kinase whose ligands are specific members of the fibroblast growth factor family. FGFR1 has been shown to be associated with Pfeiffer syndrome, and clonal eosinophilias.
ETV6 protein is a transcription factor that in humans is encoded by the ETV6 gene. The ETV6 protein regulates the development and growth of diverse cell types, particularly those of hematological tissues. However, its gene, ETV6 frequently suffers various mutations that lead to an array of potentially lethal cancers, i.e., ETV6 is a clinically significant proto-oncogene in that it can fuse with other genes to drive the development and/or progression of certain cancers. However, ETV6 is also an anti-oncogene or tumor suppressor gene in that mutations in it that encode for a truncated and therefore inactive protein are also associated with certain types of cancers.
Platelet-derived growth factor receptor beta is a protein that in humans is encoded by the PDGFRB gene. Mutations in PDGFRB are mainly associated with the clonal eosinophilia class of malignancies.
Proto-oncogene tyrosine-protein kinase Src, also known as proto-oncogene c-Src, or simply c-Src, is a non-receptor tyrosine kinase protein that in humans is encoded by the SRC gene. It belongs to a family of Src family kinases and is similar to the v-Src gene of Rous sarcoma virus. It includes an SH2 domain, an SH3 domain and a tyrosine kinase domain. Two transcript variants encoding the same protein have been found for this gene.
Tyrosine-protein kinase receptor UFO is an enzyme that in humans is encoded by the AXL gene. The gene was initially designated as UFO, in allusion to the unidentified function of this protein. However, in the years since its discovery, research into AXL's expression profile and mechanism has made it an increasingly attractive target, especially for cancer therapeutics. In recent years, AXL has emerged as a key facilitator of immune escape and drug-resistance by cancer cells, leading to aggressive and metastatic cancers.
Factor interacting with PAPOLA and CPSF1 is a protein that in humans is encoded by the FIP1L1 gene. A medically important aspect of the FIP1L1 gene is its fusion with other genes to form fusion genes which cause clonal hypereosinophilia and leukemic diseases in humans.
Platelet-derived growth factor receptor A, also termed CD140a, is a receptor located on the surface of a wide range of cell types. The protein is encoded in the human by the PDGFRA gene. This receptor binds to certain isoforms of platelet-derived growth factors (PDGFs) and thereby becomes active in stimulating cell signaling pathways that elicit responses such as cellular growth and differentiation. The receptor is critical for the embryonic development of certain tissues and organs, and for their maintenance, particularly hematologic tissues, throughout life. Mutations in PDGFRA, are associated with an array of clinically significant neoplasms, notably ones of the clonal hypereosinophilia class of malignancies, as well as gastrointestinal stromal tumors (GISTs).
Lestaurtinib is a tyrosine kinase inhibitor structurally related to staurosporine. This semisynthetic derivative of the indolocarbazole K252a was investigated by Cephalon as a treatment for various types of cancer. It is an inhibitor of the kinases fms-like tyrosine kinase 3 (FLT3), Janus kinase 2 (JAK2), tropomyosin receptor kinase (trk) A (TrkA), TrkB and TrkC.
Quizartinib, sold under the brand name Vanflyta, is a medication used for the treatment of acute myeloid leukemia.
Midostaurin, sold under the brand name Rydapt & Tauritmo both by Novartis, is a multi-targeted protein kinase inhibitor that has been investigated for the treatment of acute myeloid leukemia (AML), myelodysplastic syndrome (MDS) and advanced systemic mastocytosis. It is a semi-synthetic derivative of staurosporine, an alkaloid from the bacterium Streptomyces staurosporeus.
Fedratinib, sold under the brand name Inrebic, is an anti-cancer medication used to treat myeloproliferative diseases including myelofibrosis. It is used in the form of fedratinib hydrochloride capsules that are taken by mouth. It is a semi-selective inhibitor of Janus kinase 2 (JAK-2). It was approved by the FDA on 16 August 2019.
Clonal hypereosinophilia, also termed primary hypereosinophilia or clonal eosinophilia, is a grouping of hematological disorders all of which are characterized by the development and growth of a pre-malignant or malignant population of eosinophils, a type of white blood cell that occupies the bone marrow, blood, and other tissues. This population consists of a clone of eosinophils, i.e. a group of genetically identical eosinophils derived from a sufficiently mutated ancestor cell.
Avapritinib, sold under the brand name Ayvakit among others, is a medication used for the treatment of advanced systemic mastocytosis and for the treatment of tumors due to one specific rare mutation: it is specifically intended for adults with unresectable or metastatic gastrointestinal stromal tumor (GIST) that harbor a platelet-derived growth factor receptor alpha (PDGFRA) exon 18 mutation. Avapritinib is a kinase inhibitor.
Zotiraciclib (TG02) is a potent oral spectrum selective kinase inhibitor for the treatment of cancer. It was discovered in Singapore by S*BIO Pte Ltd and falls under the category of small molecule macrocycles. It crosses the blood brain barrier and acts by depleting Myc through the inhibition of cyclin-dependent kinase 9 (CDK9). It is one of a number of CDK inhibitors under investigation; others targeting CDK9 for the treatment of acute myeloid leukemia include alvocidib and atuveciclib. Myc overexpression is a known factor in many cancers, with 80 percent of glioblastomas characterized by this property. Zotiraciclib has been granted orphan drug designation by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for the treatment of gliomas.