BACKGROUND: Bruton's tyrosine kinase (BTK) is a key component of the B-cell receptor (BCR) pathway and a clinically validated target for small molecule inhibitors such as ibrutinib in the treatment of B-cell malignancies. Tirabrutinib (GS-4059/ONO-4059) is a selective, once daily, oral BTK inhibitor with clinical activity against many relapsed/refractory B-cell malignancies. METHODS: Covalent binding of tirabrutinib to BTK Cys-481 was assessed by LC-MSMS analysis of BTK using compound as a variable modification search parameter. Inhibition potency of tirabrutinib, ibrutinib, acalabrutinib, and spebrutinib against BTK and related kinases was studied in a dose-dependent manner either after a fixed incubation time (as used in conventional IC50 studies) or following a time course where inactivation kinetics were measured. RESULTS: Tirabrutinib irreversibly and covalently binds to BTK Cys-481. The inactivation efficiency kinact/Ki was measured and used to calculate selectivity among different kinases for each of the four inhibitors studied. Tirabrutinib showed a kinact/Ki value of 2.4 ± 0.6 × 104 M-1 s-1 for BTK with selectivity against important off-targets. CONCLUSIONS: For the BTK inhibitors tested in this study, analysis of the inactivation kinetics yielded a more accurate measurement of potency and selectivity than conventional single-time point inhibition measurements. Subtle but clear differences were identified between clinically tested BTK inhibitors which may translate into differentiated clinical efficacy and safety. GENERAL SIGNIFICANCE: This is the first study that offers a detailed side-by-side comparison of four clinically-relevant BTK inhibitors with respect to their inactivation of BTK and related kinases.
BACKGROUND:Bruton's tyrosine kinase (BTK) is a key component of the B-cell receptor (BCR) pathway and a clinically validated target for small molecule inhibitors such as ibrutinib in the treatment of B-cell malignancies. Tirabrutinib (GS-4059/ONO-4059) is a selective, once daily, oral BTK inhibitor with clinical activity against many relapsed/refractory B-cell malignancies. METHODS: Covalent binding of tirabrutinib to BTKCys-481 was assessed by LC-MSMS analysis of BTK using compound as a variable modification search parameter. Inhibition potency of tirabrutinib, ibrutinib, acalabrutinib, and spebrutinib against BTK and related kinases was studied in a dose-dependent manner either after a fixed incubation time (as used in conventional IC50 studies) or following a time course where inactivation kinetics were measured. RESULTS: Tirabrutinib irreversibly and covalently binds to BTKCys-481. The inactivation efficiency kinact/Ki was measured and used to calculate selectivity among different kinases for each of the four inhibitors studied. Tirabrutinib showed a kinact/Ki value of 2.4 ± 0.6 × 104 M-1 s-1 for BTK with selectivity against important off-targets. CONCLUSIONS: For the BTK inhibitors tested in this study, analysis of the inactivation kinetics yielded a more accurate measurement of potency and selectivity than conventional single-time point inhibition measurements. Subtle but clear differences were identified between clinically tested BTK inhibitors which may translate into differentiated clinical efficacy and safety. GENERAL SIGNIFICANCE: This is the first study that offers a detailed side-by-side comparison of four clinically-relevant BTK inhibitors with respect to their inactivation of BTK and related kinases.
Authors: Ashley C Campbell; Austin R Prater; Alexandra N Bogner; Thomas P Quinn; Kent S Gates; Donald F Becker; John J Tanner Journal: ACS Chem Biol Date: 2021-09-20 Impact factor: 5.100
Authors: Mark S Tichenor; John J M Wiener; Navin L Rao; Charlotte Pooley Deckhut; J Kent Barbay; Kevin D Kreutter; Genesis M Bacani; Jianmei Wei; Leon Chang; Heather E Murrey; Weixue Wang; Kay Ahn; Michael Huber; Elizabeth Rex; Kevin J Coe; JieJun Wu; Mark Seierstad; Scott D Bembenek; Kristi A Leonard; Alec D Lebsack; Jennifer D Venable; James P Edwards Journal: ACS Med Chem Lett Date: 2021-04-05 Impact factor: 4.345
Authors: Amy Meng; Rita Humeniuk; Juliane M Jürgensmeier; Chia-Hsiang Hsueh; Franziska Matzkies; Ethan Grant; Hoa Truong; Andrew N Billin; Helen Yu; Joy Feng; Ellen Kwan; Thomas Tarnowski; Cara H Nelson Journal: Clin Pharmacol Ther Date: 2021-10-27 Impact factor: 6.903
Authors: Angus T Voice; Gary Tresadern; Rebecca M Twidale; Herman van Vlijmen; Adrian J Mulholland Journal: Chem Sci Date: 2021-01-28 Impact factor: 9.825