Nobuhiro Oikawa

CH5424802, a Selective ALK Inhibitor Capable of Blocking the Resistant Gatekeeper Mutant

Anaplastic lymphoma kinase (ALK) is a tyrosine kinase that is constitutively activated in certain cancers, following gene alterations such as chromosomal translocation, amplification, or point mutation. Here, we identified CH5424802, a potent, selective, and orally available ALK inhibitor with a unique chemical scaffold, showing preferential antitumor activity against cancers with gene alterations of ALK, such as nonsmall cell lung cancer (NSCLC) cells expressing EML4-ALK fusion and anaplastic large-cell lymphoma (ALCL) cells expressing NPM-ALK fusion in vitro and in vivo. CH5424802 inhibited ALK L1196M, which corresponds to the gatekeeper mutation conferring common resistance to kinase inhibitors, and blocked EML4-ALK L1196M-driven cell growth. Our results support the potential for clinical evaluation of CH5424802 for the treatment of patients with ALK-driven tumors.

Design and synthesis of a highly selective, orally active and potent anaplastic lymphoma kinase inhibitor (CH5424802).

Anaplastic lymphoma kinase (ALK) receptor tyrosine kinase is considered an attractive therapeutic target for human cancers, especially non-small cell lung cancer (NSCLC). Our previous study revealed that 8,9-side-chains of 6,6-dimethyl-11-oxo-6,11-dihydro-5H-benzo[b]carbazole scaffold crucially affected kinase selectivity, cellular activity, and metabolic stability. In this work, we optimized the side-chains and identified highly selective, orally active and potent ALK inhibitor CH5424802 (18a) as the clinical candidate.

9-Substituted 6,6-Dimethyl-11-oxo-6,11-dihydro-5H-benzo[b]carbazoles as Highly Selective and Potent Anaplastic Lymphoma Kinase Inhibitors

9-Substituted 6,6-dimethyl-11-oxo-6,11-dihydro-5H-benzo[b]carbazoles were discovered as highly selective and potent anaplastic lymphoma kinase (ALK) inhibitors by structure-based drug design. The high target selectivity was achieved by introducing a substituent close to the E(0) region of the ATP binding site, which has a unique amino acid sequence. Among the identified inhibitors, compound 13d showed highly selective and potent inhibitory activity against ALK with an IC(50) value of 2.9 nM and strong antiproliferative activity against KARPAS-299 with an IC(50) value of 12.8 nM. The compound also displayed significant antitumor efficacy in an established ALK fusion gene-positive anaplastic large-cell lymphoma (ALCL) xenograft model in mice without body weight loss.

Discovery of novel tetracyclic compounds as anaplastic lymphoma kinase inhibitors.

Anaplastic lymphoma kinase (ALK) receptor tyrosine kinase is considered a promising therapeutic target for human cancers. We identified novel tetracyclic derivatives as potent ALK inhibitors. Among them, compound 27 showed strong cytotoxicity against KARPAS-299 with an IC(50) value of 21 nM and significant antitumor efficacy in ALK fusion-positive blood and solid cancer xenograft models in mice without body weight loss.

Identification of a novel vascular endothelial growth factor receptor 2 inhibitor and its effect for choroidal neovascularization in vivo.

Purpose: To select a novel orally administered VEGFR-2 (KDR/flk-1) specific tyrosine kinase inhibitor in a murine model of choroidal neovascularization (CNV). Methods: From a compound library, potent VEGFR2 inhibitors were selected by VEGF-induced phosphorylation of VEGFR-2 and RAF kinases and the proliferation analysis by HUVEC cultures and in vitro tube formation assay. CNV was induced in C57/BL6 mice using diode laser photocoagulation. The antiangiogenic effect of selected compounds was assessed by angiographic examination, in which extent of fluorescein leakage was scored and histological analysis, allowing for measurement of CNV membrane under light microscope. In addition, C57/BL6 mice were treated with daily oral administration of selected compounds for 14 days and body weights were measured. Results: Six compounds that potently inhibited VEGFR-2 were selected for further investigation. Selected compounds-treated conditions showed a dose-dependent inhibition of phosphorylation of VEGFR-2 tyrosine kinase with an IC50 of 0.0022 to 0.098 μm. Selected compounds did not inhibit the HCT116 proliferation but did demonstrate a strong inhibition effect for VEGFR-2 dependant HUVEC (IC50 = 0.0018 to 0.058 μm). Selected compounds treatment also resulted in a dose-dependent attenuation of in vitro tube formation. In the murine CNV model, #0451 is the most effective compound. The intensity of fluorescein leakage was significantly lower in doses of 12.5, 25, 50, and 100 mg/kg #0451-treated eyes compared to controls. Histologically, CNV membrane volumes were significantly reduced in #0451-treated eyes in a dose-dependent manner. At therapeutic doses of 100 mg/kg or less, there was no significant weight loss between the treated and untreated groups. Conclusion: Oral administration of #0451, a novel VEGFR-2 (KDR/flk-1)-specific tyrosine kinase inhibitor, demonstrates anti-angiogenic effects in our murine model of CNV. #0451 may be useful to treat the choroidal neovascularization associated with AMD.

Anaplastic Lymphoma Kinase Inhibitors for the Treatment of ALK-Positive Cancers

Abstract The anaplastic lymphoma kinase (ALK) inhibitor is one of the most successful oncology drug discoveries of recent years. The kinase has only recently emerged as an attractive drug target for cancer therapy after a novel oncogenic fusion gene of ALK with echinoderm microtubule-associated protein-like 4 (EML4) was identified in nonsmall cell lung cancer (NSCLC) in 2007. The fusion gene was found to be a key oncogenic driver in EML4-ALK-positive NSCLC, like breakpoint cluster region-Abelson (BCR-ABL) in chronic myeloid leukemias (CML). A number of research groups have identified promising drugs, where Pfizer succeeded in launching a potent ALK inhibitor, crizotinib, for treatment of EML4-ALK-positive NSCLC. However, acquired drug resistance caused by mutations of ALK has been identified in patients who were treated with crizotinib; therefore, many clinical and preclinical second-generation ALK inhibitors are now required to have efficacy against ALK mutants.

Abstract 4179: Potent and selective TRK inhibitor CH7057288

TRK receptor tyrosine kinases are expressed as fusion proteins encoded by various fusion genes across a wide variety of cancer types, including lung and colorectal cancer. These fusion proteins have potent oncogenic activity and are thought to be an attractive therapeutic target. In a kinase inhibitor screening we identified CH7057288, a potent and selective TRK inhibitor belonging to a novel chemical class. Our inhibitor showed selective inhibitory activity against TRKA, TRKB, and TRKC in cell-free kinase assays and suppressed proliferation of TRK fusion-positive cell lines, but not that of TRK-negative cell lines. In subcutaneously implanted xenograft models of TRK fusion-positive cells, strong tumor growth inhibition was observed. Furthermore, CH7057288 induced regression of intracranial tumors and greatly improved event-free survival in an intracranial implantation model mimicking brain metastasis. Recently, resistant mutations in TRK have been reported in patients showing disease progression after treatment with a TRK inhibitor under clinical development. Our compound maintained similar levels of in vitro and in vivo activity against some of the resistant mutants as it did to wild-type TRK. In summary, CH7057288 could be a promising therapeutic agent for TRK fusion-positive cancer. Citation Format: Hiroshi Tanaka, Hitoshi Sase, Toshiyuki Tsukaguchi, Hiromi Tanimura, Masami Hasegawa, Kiyoshi Hasegawa, Yoshiyuki Ono, Nobuhiro Oikawa, Hiroshi Sakamoto, Toshiyuki Mio. Potent and selective TRK inhibitor CH7057288 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4179. doi:10.1158/1538-7445.AM2017-4179

MITF suppression improves the sensitivity of melanoma cells to a BRAF inhibitor

Microphthalmia-associated transcription factor (MITF) is expressed in melanomas and has a critical role in melanocyte development and transformation. Because inhibition of MITF inhibits cell growth in melanoma, MITF is a potential therapeutic target molecule. Here, we report the identification of CH6868398, which has a novel chemical structure and suppresses MITF expression at the protein level in melanoma cells. CH6868398 showed cell growth inhibition activity against MITF-dependent melanoma cells both with and without BRAF mutation and also exhibited anti-tumor efficacy in a melanoma xenograft model. Because selective BRAF inhibitors are standard therapeutics for BRAF-mutated melanoma, we investigated the effect of CH6868398 with a BRAF inhibitor, PLX4720, on cell growth inhibition. The addition of CH6868398 enhanced the cell growth inhibition activity of PLX4720 in melanoma cell lines. Furthermore, combination of CH6868398 and PLX4720 efficiently suppressed MITF protein and enhanced cleavage of Caspase3 and poly (ADP-ribose) polymerase (PARP) in melanoma cell lines. These data support the therapeutic potential of CH6868398 as an anti-melanoma agent that reduces MITF protein levels in combination with BRAF inhibitors.

Abstract 3559: A new selective ALK inhibitor CH5424802 shows potent efficacy against ALK-positive cancers including the gatekeeper mutant-driven tumors

The recent development of targeted protein kinase inhibitors has provided new opportunity in cancer treatment. However, certain factors limit the efficacy of cancer therapies, such as a narrow therapeutic index caused by inhibition of multiple kinases, and the emergence of resistant mutants. Thus, kinase inhibitors with more potent and selective properties and effectiveness against resistant mutants need to be developed. Anaplastic lymphoma kinase (ALK) is a tyrosine kinase that is constitutively activated in certain cancers following gene alterations such as chromosomal translocation, amplification, or point mutation. Here, we identified CH5424802, a potent, selective, and orally available ALK inhibitor with a new chemical scaffold, showing preferential antitumor activity against cancers with gene alterations of ALK, such as non-small cell lung cancer (NSCLC) cells expressing EML4-ALK fusion and anaplastic large-cell lymphoma (ALCL) cells expressing NPM-ALK fusion in vitro and in vivo. CH5424802 inhibited ALK L1196M, which corresponds to the gatekeeper mutation conferring common resistance to kinase inhibitors, and blocked EML4-ALK L1196M-driven tumors. Our results support the potential for the clinical evaluation of CH54242802 for long-term treatment of patients with ALK-driven tumors. CH5424802 is currently being investigated in Phase I/II clinical trials for patients with ALK-positive NSCLC. 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 3559. doi:10.1158/1538-7445.AM2011-3559

Abstract DDT01-02: CH5424802: A selective ALK inhibitor

Recent development of targeted protein kinase inhibitors provides new opportunity in cancer treatment. On the other hand, there are some cases limiting the efficacy of cancer therapies, owing to narrow therapeutic index by inhibiting multiple kinase, and the emergence of resistant mutants. Thus, the development of kinase inhibitors with more potent and selective properties and effectiveness to resistant mutants is needed. Anaplastic lymphoma kinase (ALK) is a tyrosine kinase that is constitutively activated in some cancers, due to gene alterations such as chromosomal translocation, amplification, or point mutation. Here we have identified CH5424802, a potent, selective and orally available ALK inhibitor with a new chemical scaffold. CH5424802 showed preferential antitumor activity against cancers with gene alterations of ALK, such as non-small cell lung cancer (NSCLC) cells expressing EML4-ALK fusion, anaplastic large-cell lymphoma (ALCL) cells expressing NPM-ALK fusion, and neuroblastoma with gene amplification of ALK in vitro and in vivo. Also, CH5424802 could inhibit ALK L1196M, which corresponds to the gatekeeper mutation conferring common resistance to kinase inhibitors, and block the growth of EML4-ALK L1196M-driven cells. CH5424802 is currently being investigated in phase I/II clinical trials for patients with ALK-positive NSCLC. 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 DDT01-02. doi:10.1158/1538-7445.AM2011-DDT01-02