Tadashi Terasaka

Structure-Based de novo design of non-nucleoside adenosine deaminase inhibitors

We searched for non-nucleoside inhibitors of adenosine deaminase by rational structure-based de novo design and succeeded in the discovery of 1-(1-hydroxy-4-phenyl-2-butyl)imidazole-4-carboxamide (FR221647: K(i)=5.9 microM to human ADA) as a novel inhibitor with moderate activity and good pharmacokinetics compared with the known inhibitors pentostatin and EHNA.

Inhibition of antigen-induced airway inflammation and hyperresponsiveness in guinea pigs by a selective antagonist of "chemoattractant receptor homologous molecule expressed on Th2 cells" (CRTH2).

Chemoattractant receptor homologous molecule expressed on T helper type 2 cells (CRTH2) is a PGD2 receptor found on eosinophils, basophils, and Th2 type T cells which exhibits chemotaxis and functions in activation cascades. However, while a number of CRTH2 antagonists, including ramatroban, are known to exert activity in certain animal models, activity in a guinea pig model of EA-induced airway hyperresponsiveness has not been demonstrated. The newly developed CRTH2 antagonist ASP5642 has shown antagonistic activity against human and guinea pig CRTH2 in previous studies and has also been found effective in treating guinea pig models of airway inflammation and airway hyperresponsiveness. While previous studies have used animals such as rats and mice to evaluate CRTH2 antagonist effects, ours is the first attempt to evaluate CRTH2 function in a guinea pig asthma model, which may prove useful in evaluating the compounds effects in humans, given the comparable airway function between the two species taken together, these data from the present study strongly suggest the utility of ASP5642 in investigating the role of CRTH2 in inflammatory responses and as a drug treatment for human asthma.

ASP5878, a Novel Inhibitor of FGFR1, 2, 3, and 4, Inhibits the Growth of FGF19-Expressing Hepatocellular Carcinoma

Hepatocellular carcinoma is an aggressive cancer with poor prognosis. Fibroblast growth factor 19, a member of the fibroblast growth factor family, is a ligand for fibroblast growth factor receptor 4. Moreover, it plays a crucial role in the progression of hepatocellular carcinoma. ASP5878 is a novel inhibitor of fibroblast growth factor receptors 1, 2, 3, and 4 that is under development. It inhibits fibroblast growth factor receptor 4 kinase activity with an IC50 of 3.5 nmol/L. ASP5878 potently suppressed the growth of the fibroblast growth factor 19–expressing hepatocellular carcinoma cell lines Hep3B2.1-7, HuH-7, and JHH-7. In the Hep3B2.1-7 cell line, ASP5878 inhibited the phosphorylation of fibroblast growth factor receptor 4 and its downstream signaling molecules as well as induced apoptosis. Oral administration of ASP5878 at 3 mg/kg induced sustained tumor regression in a subcutaneous xenograft mouse model using Hep3B2.1-7. In HuH-7, an orthotopic xenograft mouse model, ASP5878 induced complete tumor regression and dramatically extended the survival of the mice. These results suggest that ASP5878 is a potentially effective therapeutic agent for hepatocellular carcinoma patients with tumors expressing fibroblast growth factor 19. Mol Cancer Ther; 16(1); 68–75. ©2016 AACR.

Discovery of novel and potent CRTH2 antagonists.

High throughput screening of our chemical library for CRTH2 antagonists provided a lead compound 1a. Initial optimization of the lead led to the discovery of a novel, potent and orally bioavailable CRTH2 antagonist 17.

Abstract B188: Preclinical antitumor activity of ASP8273, a mutant-selective irreversible EGFR inhibitor in an AXL-overexpressing NSCLC model

Background: Activating mutations of epidermal growth factor receptor (EGFR) are associated with the high sensitivity of non-small cell lung cancer (NSCLC) patients to EGFR tyrosine kinase inhibitors (TKIs) like erlotinib. However, acquired resistance limits the clinical efficacy of EGFR-TKIs. Several mechanisms of the acquired resistance have been described, including gatekeeper T790M mutation and MET amplification. Overexpression of AXL, a receptor type tyrosine kinase and/or its ligand, GAS-6 have been identified in a subset of NSCLC patients with acquired resistance, and inhibition of AXL has been shown to restore sensitivity to erlotinib in nonclinical resistant models, suggesting that AXL is also involved in EGFR-TKI resistance of NSCLC. ASP8273 is a mutant-selective irreversible EGFR inhibitor currently in clinical trials (ClinicalTrials.gov Identifier: NCT02113813, NCT02192697, NCT02500927). We have previously reported that ASP8273 selectively inhibited kinase activities of EGFR activating and T790M mutations compared to wild type EGFR, and induced tumor regression in HCC827 and NCI-H1975 xenografted mice. In this study, we evaluated the antitumor activity of ASP8273 against AXL overexpressing PC-9 cells. Method: PC-9 vec. cells and PC-9 AXL cells were constructed by the infection of pMXs-puro vector and AXL coding vector, respectively into PC-9, a NSCLC cell line with EGFR exon 19 del activating mutation. Inhibitory effects of ASP8273 and other EGFR-TKIs, including erlotinib on EGFR and AXL signaling and cell proliferation were investigated in PC-9 vec. and PC-9 AXL cells. In vivo antitumor effect was also examined in subcutaneously implanted with PC-9 AXL. Result: ASP8273 at 1 μmol/L inhibited cell growth associated with the inhibition of EGFR, AXL, AKT, and ERK phosphorylation in PC-9 AXL. On the other hand, EGFR-TKIs at 1 μmol/L did not show cell growth inhibition in PC-9 AXL cells, whereas those showed cell growth inhibition in PC-9 vec. cells. EGFR-TKIs inhibited the phosphorylation of EGFR but not AXL, AKT, and ERK in PC-9 AXL cells. In an in vivo xenograft model using PC-9 AXL, once-daily oral administration of ASP8273 at 50 mg/kg induced statistically significant tumor growth inhibition although the other EGFR-TKIs did not. Conclusion: These results suggest that overexpression of AXL confers resistance to EGFR-TKIs in NSCLC cells and ASP8273 may show antitumor activity against EGFR-TKIs-resistant NSCLC patients with AXL expression. Citation Format: Naoki Kaneko, Hiroaki Tanaka, Satoshi Konagai, Hiroko Yamamoto, Hideki Sakagami, Tomohiro Eguchi, Takahiro Matsuya, Masamichi Mori, Hiroyuki Koshio, Tadashi Terasaka, Masaaki Hirano, Sadao Kuromitsu, Masahiro Takeuchi. Preclinical antitumor activity of ASP8273, a mutant-selective irreversible EGFR inhibitor in an AXL-overexpressing NSCLC model. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B188.

ASP5878, a Selective FGFR Inhibitor, to Treat FGFR3-Dependent Urothelial Cancer with or without Chemoresistance.

FGF/FGFR gene aberrations such as amplification, mutation and fusion are associated with many types of human cancers including urothelial cancer. FGFR kinase inhibitors are expected to be a targeted therapy for urothelial cancer harboring FGFR3 gene alternations. ASP5878, a selective inhibitor of FGFR1, 2, 3 and 4 under clinical investigation, selectively inhibited cell proliferation of urothelial cancer cell lines harboring FGFR3 point mutation or fusion (UM‐UC‐14, RT‐112, RT4 and SW 780) among 23 urothelial cancer cell lines. Furthermore, ASP5878 inhibited cell proliferation of adriamycin‐resistant UM‐UC‐14 cell line harboring MDR1 overexpression and gemcitabine‐resistant RT‐112 cell line. The protein expression of c‐MYC, an oncoprotein, in gemcitabine‐resistant RT‐112 cell line was higher than that in RT‐112 parental cell line and ASP5878 decreased the c‐MYC expression in both RT‐112 parental and gemcitabine‐resistant RT‐112 cell lines. Once‐daily oral administration of ASP5878 exerted potent antitumor activities in UM‐UC‐14, RT‐112 and gemcitabine‐resistant RT‐112 xenograft models without affecting body weight. These findings suggest that ASP5878 has the potential to be an oral targeted therapy against urothelial cancer harboring FGFR3 fusion or FGFR3 point mutation after the acquisition of gemcitabine‐ or adriamycin‐resistance.

Abstract A170: Preclinical antitumor activity of ASP5878, a novel inhibitor of FGFR1, 2, 3 and 4, in bladder cancer harboring FGFR3-fusion or -mutation

Background: Fibroblast growth factor (FGF) / FGF receptor (FGFR) gene aberrations such as amplification, mutation and fusion are associated with many types of human cancers. Recently, FGFR3 fusions (FGFR3-TACC3 and FGFR3-BAIAP2L1), which have potent oncogenic activity, have been discovered in bladder and lung cancer. FGFR kinase inhibitors are expected to be a targeted therapy for bladder cancer harboring FGFR3 gene alternations. A phase I clinical trial of ASP5878, a novel inhibitor of FGFR1, 2, 3 and 4, is ongoing (NCT02038673). Method: We tested selectivity of ASP5878 among 128 kinases and sensitivity of ASP5878 on cell proliferation of bladder cancer cell lines. FGFR3 and ERK phosphorylation in FGFR3-dependent bladder cancer cell lines were evaluated with sandwich ELISA or Western blotting. In vivo antitumor effects of ASP5878 were examined in subcutaneously implanted bladder cancer cell lines in nude mice. Results: Among 128 kinases, only 9 kinases including wild-type FGFR1-4 and FGFR3/4 mutants were inhibited more than 50% by ASP5878 (200 nmol/L). The IC50 values of ASP5878 against FGFR1, 2, 3 and 4 kinases are 0.47, 0.60, 0.74 and 3.5 nmol/L, respectively. In addition, ASP5878 suppressed cell growth in several cancer cell lines harboring FGF / FGFR gene alternations. Among 25 bladder cancer cell lines, ASP5878 selectively inhibited cell proliferation of UM-UC-14 [FGFR3 (S249C) positive], RT-112 (FGFR3-TACC3 positive), RT-4 (FGFR3-TACC3 positive) and SW780 (FGFR3-BAIAP2L1 positive). FGFR3 and ERK phosphorylation in UM-UC-14 and RT-112 cell lines were inhibited by ASP5878 in a concentration-dependent manner. Furthermore, ASP5878 inhibited cell proliferation of gemcitabine-resistant RT-112 cells and adriamycin-resistant UM-UC-14 cells. Once-daily oral administration of ASP5878 induced tumor regression at 1 and 3 mg/kg in UM-UC-14 and RT-112 xenograft models, respectively, without body weight loss. Conclusions: These findings suggest that ASP5878 has the potential to be an oral targeted therapy against bladder cancer harboring FGFR3-TACC3 fusion or FGFR3 point mutation even after the acquisition of chemoresistance. Citation Format: Tomoyuki Suzuki, Aya Kikuchi, Taisuke Nakazawa, Masateru Iizuka, Ayako Nakayama, Minoru Kameda, Nobuaki Shindoh, Tadashi Terasaka, Masaaki Hirano, Sadao Kuromitsu. Preclinical antitumor activity of ASP5878, a novel inhibitor of FGFR1, 2, 3 and 4, in bladder cancer harboring FGFR3-fusion or -mutation. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A170.

Abstract A172: Preclinical antitumor activity of ASP5878, a novel inhibitor of FGFR1, 2, 3 and 4, in FGF19-expressing hepatocellular carcinoma

Background: Fibroblast growth factor (FGF) / FGF receptor (FGFR) gene aberrations such as amplification, mutation and fusion are associated with many types of human cancers. Recently, FGF19 overexpression was observed in approximately 50% of hepatocellular carcinoma (HCC) patients. The FGF19-FGFR4 signaling has been implicated in the development of HCCs in mice. FGFR4 kinase inhibitors are expected to be a targeted therapy for FGF19-expressing HCC. A phase I clinical trial of ASP5878, a novel inhibitor of FGFR1, 2, 3 and 4, is ongoing (NCT02038673). Method: We tested selectivity of ASP5878 among 128 kinases and sensitivity of ASP5878 on cell proliferation of HCC cell lines. Activation of FRS2 and ERK, downstream molecules of FGFR signaling, and PARP cleavage in FGF19 expressing HCC cell lines were evaluated with Western blotting. In vivo antitumor effects of ASP5878 were examined in HCC subcutaneous xenograft and orthotopic inoculation mouse models. Finally, plasma levels of FGF19 were measured after dosing ASP5878. Results: Among 128 kinases, only 9 kinases including FGFR1-4 and FGFR3/4 mutations were inhibited more than 50% by ASP5878 (200 nmol/L). The IC50 values of ASP5878 against FGFR1, 2, 3 and 4 kinases were 0.47, 0.60, 0.74 and 3.5 nmol/L, respectively. ASP5878 inhibited cell proliferation of HCC cell lines with FGF19 overexpression. IC50 values were 8.5, 27, and 21 nmol/L in Hep3B2.1-7, HuH-7 and JHH-7, respectively. ASP5878 inhibited activation of downstream signaling molecules, FRS2 and ERK, and induced apoptosis in Hep3B2.1-7 cells. Oral dosing of ASP5878 at 3 mg/kg induced sustained tumor regression in the Hep3B2.1-7 subcutaneous xenograft model, which was poorly responsive to sorafenib. In an HuH-7 orthotopic inoculation mouse model, ASP5878 induced complete tumor regression and dramatically extended the survival. In addition, oral dosing of ASP5878 reduced plasma levels of FGF19 in the HuH-7 subcutaneous xenograft model.Conclusion: These results suggest that ASP5878 is a potentially effective therapeutic agent for FGF19-expressing HCC. Citation Format: Takashi Futami, Hidetsugu Okada, Rumi Kihara, Tatsuya Kawase, Ayako Nakayama, Tomoyuki Suzuki, Minoru Kameda, Nobuaki Shindoh, Tadashi Terasaka, Masaaki Hirano, Sadao Kuromitsu. Preclinical antitumor activity of ASP5878, a novel inhibitor of FGFR1, 2, 3 and 4, in FGF19-expressing hepatocellular carcinoma. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A172.

Non-nucleoside adenosine deaminase inhibitors: 2000 – 2004

Adenosine deaminase (ADA) is a crucial enzyme in purine metabolism that irreversibly deaminates adenosine to form inosine. ADA is ubiquitous in human tissues and plays a crucial role in immune system development. ADA inhibitors may be useful for the treatment of ischaemic injury, hypertension, lymphomas and leukaemia. Furthermore, ADA inhibitors have recently also been considered as anti-inflammatory drugs. Most ADA inhibitors to date are purine nucleosides or alkyladenine analogues that have poor pharmacokinetics and/or several toxicities. ADA inhibitors without these problems may improve the treatment of leukaemia and also have potential for use in many other clinical conditions. This hypothesis has generated considerable interest in the development of non-nucleoside ADA inhibitors. Recently, a Fujisawa non-nucleoside ADA inhibitor demonstrated in vivo efficacy in inflammation and lymphoma models after oral administration. This review describes recent advances in the development of non-nucleoside ADA inhibitors, based on the patent literature from January 2000 to December 2004.