Nemtabrutinib (ARQ 531, MK-1026) is an ATP-competitive tyrosine kinase inhibitor designed to target BTK with an IC50 of 0.85 nM. It also has a distinct kinase selectivity profile with strong inhibitory activity against several key oncogenic drivers from T
Nemtabrutinib (ARQ 531, MK-1026) is an ATP-competitive tyrosine kinase inhibitor designed to target BTK with an IC50 of 0.85 nM. It also has a distinct kinase selectivity profile with strong inhibitory activity against several key oncogenic drivers from TEC, Trk and Src family kinases.
ARQ 531 potently inhibited BTK (IC50 = 0.85 nM), the binding potency was accompanied by long residence time (51 min). ARQ 531 selectively inhibits BCR signaling dependent PI3K/AKT/mTOR, Ras/Raf/Erk and Rap-GTPase-Cofilin pathways in TMD8 cells. It potently inhibits proliferation of hematological malignant cell lines both sensitive and resistant to ibrutinib addicted to BCR signaling[1]. Unlike ibrutinib, ARQ 531 suppressed both the upstream activating signals (via inhibition of a select member of Src kinase family) and the downstream signaling pathways (via pAKT and pERK kinases). In GCB-DLBCL cell lines (SUDHL-4 and DOHH-2), ARQ 531 potently suppressed expression of anti-apoptotic c-Myc and BCL6 oncoproteins in a dose dependent fashion, and concomitantly induced apoptotic cleavage of PARP protein[2].
ARQ 531 has potent anti-tumor activity was observed in both ABC-DLBCL and GCB-DLBCL mouse xenograft models[1]. ARQ 531 crosses the blood, brain-barrier[2]. In a single oral dose study of 10mg/kg in monkeys, the bioavailability of ARQ 531 is 72.4% with a Cmax of 9 μM and a half-life greater than 24 hours[3].
[1] Sudharshan Eathiraj, et al. EHA Congress. 2017, ePoster number: E1400. [2] Sudharshan Eathiraj, et al. AACR Cancer Res 2018. 78(13 Suppl):Abstract nr 1963. [3] Sean D. Reiff, et al. Blood. 2016, 128:3232.
Cell experiment: | Biochemical inhibition assay is measured using full length BTK constructs of wild type or C481S mutant. Profiling on 236 kinases identifies 45 kinases with >50% inhibition at 200 nM concentration of ARQ 531. Subsequently, the potency of this ATP competitive inhibitor is determined on such kinases at the physiological 1 mM ATP concentration cells are treated with increasing concentrations of inhibitors in SUDHL-4 for 2 hours, following stimulation with either anti-IgM or growth factors cells are lysed for Western blot analysis[1]. |
Animal experiment: | Mice[1]Six week old female CB-17 SCID mice (1-2 weeks) are used. Mice are housed in sterile micro isolator cages, five mice per cage and receive food and water ad libitum. Female SCID mice are implanted subcutaneously with 8x106 TMD8 cells in 0.2 mL HBSS with 50% standard concentration BD matrigel in the upper right flank area. Mice are monitored and staged on day 14 (post injection of tumor cells) when size reaches approximately 400 mg. Oral daily dosing with ARQ 531 at 100 mg/kg, vinblastine or vehicle began on stage day. Tumor measurements and body weights are collected three times a week. In vivo Target and pathway inhibition is studied in mouse TMD8 xenograft model. Percent inhibition relative to the vehicle control is determined using densitometry analysis and the intensity of actin band is used as a loading control and the percentage of vehicle group is designated as 100%. DBA1/J mice are immunized with collagen to develop the arthritis, following the onset of arthritis, mice are randomized into treatment groups. Treatment is initiated by oral dosing of ARQ 531 at 25, 50 and 75 mg/kg and continued daily through arthritis day 14. Clinical scores are assessed for each of the paws on study arthritis days 1-15. Dexamethasone at 3 mg/kg is used as a control[1]. |
参考文献: [1]. S Eathiraj, et al. Targeting Ibrutinib-Resistant BTK-C481S Mutation with ARQ 531, a Reversible Non-Covalent Inhibitor of BTK. Clinical Lymphoma Myeloma & Leukemia, 2016, 16: S47-S48. | |
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