Itsuro Shimada

The Selective Anaplastic Lymphoma Receptor Tyrosine Kinase Inhibitor ASP3026 Induces Tumor Regression and Prolongs Survival in Non–Small Cell Lung Cancer Model Mice

Activation of anaplastic lymphoma receptor tyrosine kinase (ALK) is involved in the pathogenesis of several carcinomas, including non–small cell lung cancer (NSCLC). Echinoderm microtubule–associated protein like 4 (EML4)-ALK, which is derived from the rearrangement of ALK and EML4 genes, has been validated as a therapeutic target in a subset of patients with NSCLC. Here, we investigated the effects of ASP3026, a novel small-molecule ALK inhibitor, against ALK-driven NSCLC. ASP3026 inhibited ALK activity in an ATP-competitive manner and had an inhibitory spectrum that differed from that of crizotinib, a dual ALK/MET inhibitor. In mice xenografted with NCI-H2228 cells expressing EML4-ALK, orally administered ASP3026 was well absorbed in tumor tissues, reaching concentrations >10-fold higher than those in plasma, and induced tumor regression with a wide therapeutic margin between efficacious and toxic doses. In the same mouse model, ASP3026 enhanced the antitumor activities of paclitaxel and pemetrexed without affecting body weight. ASP3026 also showed potent antitumor activities, including tumor shrinkage to a nondetectable level, in hEML4-ALK transgenic mice and prolonged survival in mice with intrapleural NCI-H2228 xenografts. In an intrahepatic xenograft model using NCI-H2228 cells, ASP3026 induced continuous tumor regression, whereas mice treated with crizotinib showed tumor relapse after an initial response. Finally, ASP3026 exhibited potent antitumor activity against cells expressing EML4-ALK with a mutation in the gatekeeper position (L1196M) that confers crizotinib resistance. Taken together, these findings indicate that ASP3026 has potential efficacy for NSCLC and is expected to improve the therapeutic outcomes of patients with cancer with ALK abnormality. Mol Cancer Ther; 13(2); 329–40. ©2014 AACR.

Synthesis and biological evaluation of 3-biphenyl-4-yl-4-phenyl-4H-1,2,4-triazoles as novel glycine transporter 1 inhibitors.

We describe the preparation and evaluation of a novel series of glycine transporter 1 (GlyT1) inhibitors derived from a high-throughput screening hit. The SAR studies resulted in the discovery of 3-biphenyl-4-yl-4-(2-fluorophenyl)-5-isopropyl-4H-1,2,4-triazole (6p). A pharmacokinetic study was also conducted and revealed that 6p had excellent oral bioavailability and ameliorated learning impairment in passive avoidance tasks in mice.

Atropisomeric 4-phenyl-4H-1,2,4-triazoles as selective glycine transporter 1 inhibitors.

We report on the optimization of 4H-1,2,4-triazole derivatives to increase their activity and selectivity as glycine transporter 1 (GlyT1) inhibitors. Structure-activity relationship exploration resulted in the identification of a 3-[3-ethyl-5-(6-phenylpyridin-3-yl)-4H-1,2,4-triazol-4-yl]-2-methylbenzonitrile (14u) compound with markedly higher selectivity for GlyT1. Physiochemical studies revealed that 14u exists as a stable pair of atropisomers under physiological conditions. We successfully separated the atropisomers to obtain active enantiomer (R)-14u, which displayed favorable pharmacokinetic properties, as well as positive results in the mice Y-maze test.

Gilteritinib, a FLT3/AXL inhibitor, shows antileukemic activity in mouse models of FLT3 mutated acute myeloid leukemia

SummaryAdvances in the understanding of the molecular basis for acute myeloid leukemia (AML) have generated new potential targets for treatment. Fms-like tyrosine kinase 3 (FLT3) is one of the most frequently mutated genes in AML and mutations in this gene are associated with poor overall survival. AXL plays a role in the activation of FLT3 and has been implicated in the pathogenesis of AML. The studies reported here evaluated the ability of a novel FLT3/AXL inhibitor, gilteritinib, to block mutated FLT3 in cellular and animal models of AML. Initial kinase studies showed that gilteritinib, a type I tyrosine kinase inhibitor, was highly selective for both FLT3 and AXL while having weak activity against c-KIT. Gilteritinib demonstrated potent inhibitory activity against the internal tandem duplication (FLT3-ITD) and FLT3-D835Y point mutations in cellular assays using MV4–11 and MOLM-13 cells as well as Ba/F3 cells expressing mutated FLT3. Gilteritinib also inhibited FLT3-F691 mutations, although to a lesser degree, in these assays. Furthermore, gilteritinib decreased the phosphorylation levels of FLT3 and its downstream targets in both cellular and animal models. In vivo, gilteritinib was distributed at high levels in xenografted tumors after oral administration. The decreased FLT3 activity and high intratumor distribution of gilteritinib translated to tumor regression and improved survival in xenograft and intra-bone marrow transplantation models of FLT3-driven AML. No overt toxicity was seen in mouse models treated with gilteritinib. These results indicate that gilteritinib may be an important next-generation FLT3 inhibitor for use in the treatment of FLT3 mutation-positive AML.

Synthesis and biological evaluation of (4H-1,2,4-triazol-4-yl)isoquinoline derivatives as selective glycine transporter 1 inhibitors.

To identify novel glycine transporter 1(GlyT1) inhibitors with greater selectivity relative to GlyT2 and improved aqueous solubility, we synthesized a series of 4H-1,2,4-triazole derivatives with heteroaromatic rings at the 4-position and investigated their structure-activity relationships. Replacement of the 2-fluorophenyl group of lead compound 5 with various aromatic groups led to the identification of 5-(3-biphenyl-4-yl-5-ethyl-4H-1,2,4-triazol-4-yl)isoquinoline (15) with 38-fold selectivity between GlyT1 and GlyT2. 15 also showed improved aqueous solubility and in vivo efficacy on (+)-HA966-induced hyperlocomotion in mice over the lead compound.

Abstract 2678: First demonstration of in vivo PET imaging for ALK inhibitor using [11C]ASP3026, a novel brain-permeable type of ALK inhibitor.

The recent breakthrough identifying the onco-driver fusion mutant of ALK kinase and its inhibitor crizotinib commercially termed as Xalkori has brought significant benefit to a portion of non-small cell lung cancer (NSCLC) patients. However, a number of clinical issues in ALK-positive lung cancer remain, involving resistance to crizotinib caused by secondary mutation, amplification of the ALK gene, activation of alternative pathways, and metastatic resistance, etc. Among these mechanisms, brain metastasis is a critical issue because of its poor prognosis. We have recently identified ASP3026 as a novel type of ALK inhibitor under development, and have reported that ASP3026 shows antitumor activities in several crizotinib-refractory models including gate keeper mutants. Here, we report the first PET imaging of an ALK inhibitor using [11C]ASP3026. The study has revealed that ASP3026 shows a brain tumor permeability in an intracranial xenograft model of H2228-luc ALK fusion positive cells. In this model, significant growth inhibition of H2228 intracranial tumor was observed by treatment with ASP3026 (10 mg/kg, q.d.), but not with crizotinib (10 mg/kg, q.d.) as determined by a bioluminescent imaging technique. Pharmacokinetic measurements of ASP3026 and crizotinib indicated that ASP3026 showed a four-fold better brain penetration than crizotinib on AUC0-24 base analysis, with a brain/plasma ratio=0.72 and 0.18 for ASP3026 and crizotinib, respectively. Further, we synthesized positron-labeled [11C]ASP3026 and performed PET imaging to clarify penetration of ASP3026 into cranial tumors. Quantitative analysis of [11C]ASP3026-PET data indicated that ASP3026 showed higher uptake into cranial tumors (SUV=3.0) than brain parenchyma (SUV=0.8). Moreover, comparison of pharmacokinetic profiles in several tumor models showed that tumor uptake of ASP3026 was higher than that of surrounding tissue, suggesting that tumor accumulation of ASP3026 was dependent on the microenvironment of tumor. Taken together, these results suggest that ASP3026 has favorable properties that may be useful for the treatment of brain metastases in ALK-positive NSCLC patients. Thus, PET imaging using 11C-labeled ASP3026 may allow the tumor penetration of ASP3026 to be clarified in any primary or metastatic tumor site. Citation Format: Hiroshi Fushiki, Rika Saito, Makoto Jitsuoka, Itsuro Shimada, Yutaka Kondoh, Hideki Sakagami, Yukiko Funatsu, Akihiro Noda, Yoshihiro Murakami, Sousuke Miyoshi, Yoko Ueno, Satoshi Konagai, Takatoshi Soga, Shintaro Nishimura, Masamichi Mori, Sadao Kuromitsu. First demonstration of in vivo PET imaging for ALK inhibitor using [11C]ASP3026, a novel brain-permeable type of ALK inhibitor. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2678. doi:10.1158/1538-7445.AM2013-2678

Abstract 2821: Anti-tumor activity of ASP3026, – A novel and selective ALK inhibitor -

EML4-ALK is an oncogenic fusion kinase which was first identified in non-small cell lung cancer (NSCLC), and is regarded as an attractive therapeutic target for treating a subpopulation of NSCLC patients. We synthesized and screened chemical compounds utilizing an ALK kinase inhibition assay aimed at the EML4-ALK target for drug discovery, and found ASP3026, a novel and selective inhibitor for the ALK kinase. ASP3026 inhibited ALK kinase activity at an IC 50 value of 3.5 nmol/L, and showed more selective ALK inhibition in a Tyr-kinase panel than PF02341066. In an anchorage independent in vitro cell growth assay, ASP3026 inhibited the growth of NCI-H2228, a human NSCLC tumor cell line endogenously expressing EML4-ALK variant 3, with an IC 50 value of 64.8 nmol/L. This growth inhibition was accompanied with the decrease in phosphorylation of EML4-ALK protein, indicating that ASP3026 exerts its anti-proliferative activity through ALK kinase inhibition. The plasma and tumor concentrations of ASP3026 in mice xenografted with NCI-H2228 tumor after a 5-day repeated oral dosing of ASP3026 (10 mg/kg once daily) were determined using high-performance liquid chromatography-tandem mass spectrometry. Tmax values were 4 h in plasma and tumors. Cmax values at the corresponding doses were, respectively, 875 nmol/mL and 15500 nmol/g. A decrease of phophorylated EML4-ALK was confirmed 4 hours after a single administration of ASP3026 at 10 mg/kg by Western-blot analysis. The antitumor activities were evaluated using mice bearing subcutaneous NCI-H2228 tumor xenografts. ASP3026, administered as twice daily oral dosing for 14 days, induced dose dependent anti-tumor effects starting at 1 mg/kg with strong regression at 10, 30 and 100 mg/kg. No influence on body weights was observed in all dose range of ASP3026 treated-mice. In contrast, PF02341066 at twice daily oral dosing resulted in growth inhibition of NCI-H2228 xenografted tumors at 10 mg/kg, and tumor regression at 30 mg/kg. In addition, 100 mg/kg of PF02341066 was intolerable in this model. These results suggest that ASP3026 is a novel and selective ALK inhibitor, which is orally active, and will possibly target NSCLC patients possessing the EML4-ALK fusion. We are starting phase I clinical trials of ASP3026 in the near future. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2821. doi:10.1158/1538-7445.AM2011-2821

An efficient preparative route to 7-ethyl-1H-furo[2,3-g]indazole

A new and efficient route to 7-ethyl-1H-furo[2,3-g]indazole (2) has been developed. Treatment of 4,5-dihydro-7-(1-hydroxyethyl)indazole (12) with hydrochloric acid in ethanol resulted in a concomitant dehydration and aromatization to afford the title compound in good yield.

Abstract 866: ASP3026, a selective ALK inhibitor, induces tumor regression in a crizotinib-refractory model and prolongs survival in an intrapleurally xenograft model

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL EML4-ALK translocation has been validated as a therapeutic target in a subset of non-small cell lung cancer (NSCLC) patients. In clinical settings, crizotinib has shown promising response rates in patients with EML4-ALK positive NSCLC, while disease relapse has been observed in several sites, including the lungs. Our previous studies found that ASP3026, a selective ALK inhibitor, had higher kinase selectivity than crizotinib and induced regression of tumors expressing EML4-ALK with a gate-keeper mutation that confers resistance to crizotinib. Here, we evaluated the antitumor activity of ASP3026 and crizotinib against orthotopic lung and intrapleural tumors in mice using luciferase-expressing NCI-H2228, a human NSCLC tumor cell line endogenously expressing EML4-ALK. In an orthotopic lung model, implanted cells were monitored using bioluminescent imaging (BLI) of the chest area. ASP3026 and crizotinib were administered orally at once daily doses ranging from 3 to 30 mg/kg (starting after confirmation of tumor growth). ASP3026 at 30 mg/kg induced tumor regression by 27 days after the start of administration; in contrast, crizotinib at 30 mg/kg induced regression during the first 7 days of administration, although tumors subsequently regrew despite continuous drug administration. After tumor regrowth had been established by the first cycle treatment of crizotinib, substantial regression was achieved by subsequent administration of ASP3026 at 30 mg/kg against the crizotinib-refractory tumors. In an intrapleural xenograft model, disease-related mortality was observed in tested animals, with a median survival time (MST) of 39 days in vehicle-treated control mice and 71 days in crizotinib-treated animals at 30 mg/kg. In contrast, no mice receiving ASP3026 treatment at 30 mg/kg died during the experimental period (90 days). These effects were accompanied by change in the bioluminescent emissions, with crizotinib-treated mice showing increased emissions following the initial reduction, while ASP3026-induced reduction continuing throughout the experimental period. The mean bioluminescent emission in the group treated with ASP3026 was significantly lower than in the crizotinib-treated group, indicating that ASP3026-treated animals exhibited lower tumor burden than crizotinib-treated ones.Taken together, these results suggest that ASP3026 is effective in producing shrinkage of tumors refractory to crizotinib and shows superior efficacy to crizotinib against intrapleural metastatic tumors with respect to prolonging survival. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 866. doi:1538-7445.AM2012-866

Abstract 918: ASP3026, a selective ALK inhibitor, shows anti-tumor activity in a mouse model xenografted with NCI-H2228 intracranially.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC EML4-ALK translocation has been validated as a therapeutic target in a subset of non-small cell lung cancer (NSCLC) patients. Crizotinib, an FDA-approved ALK inhibitor, is effective against several types of human cancers with ALK abnormalities including EML4-ALK, RANBP2-ALK and ALK mutations. However, long-term treatment is often limited by the development of resistant tumors and distant metastases. Multiple brain metastases are a critical issue because of their poor prognosis despite the standard radiotherapy. The reason for metastases and development of tumor in the brain could be attributable to the poor penetration of crizotinib into central nervous system, as previously reported. ASP3026 is a selective ALK inhibitor which shows antitumor activities in several crizotinib-refractory models including gate keeper mutants. Here, we established an intracranial xenograft model by implanting NCI-H2228 cells directly in the brain of immunocompromised mice. Xenografted cells develop intracranial tumors which grow in murine brain and eventually become lethal, resembling the clinical tumors that metastasized in the brain. To determine the anti-tumor activity against tumors in the brain, mice were treated with ASP3026 or crizotinib for 2 weeks and held to observe survival duration. Ten, 30 and 100 mg/kg daily oral administration of ASP3026 dose dependently inhibited tumor growth in brain, and tumor regression was achieved in 30 and 100 mg/kg groups confirmed by MR imaging. These results were supported by the observation that Ktrans and IAUC (90s) were significantly decreased in 30 and 100 mg/kg groups using dynamic contrast enhanced MR imaging (DCE-MRI). Furthermore, ASP3026 significantly prolonged the survival of tumor bearing mice compared to vehicle treatment group. On the other hand, 30mg/kg daily oral administration of crizotinib inhibited the tumor growth during the treatment period but did not produce significant survival benefit. Taken together, these results indicate that ASP3026 shows better efficacy than crizotinib and improves overall survival in an intracranial mouse xenograft model, suggesting that ASP3026 may have potential to benefit EML4-ALK positive NSCLC patients with brain metastases. Citation Format: Satoshi Konagai, Hiroshi Fushiki, Hideki Sakagami, Yoko Ueno, Masamichi Mori, Itsuro Shimada, Yutaka Kondoh, Sousuke Miyoshi, Shintaro Nishimura, Sadao Kuromitsu. ASP3026, a selective ALK inhibitor, shows anti-tumor activity in a mouse model xenografted with NCI-H2228 intracranially. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 918. doi:10.1158/1538-7445.AM2013-918