Preclinical characterization of pirtobrutinib, a highly selective, noncovalent (reversible) BTK inhibitor
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ABSTRACT:
SUBMITTER: Gomez E
PROVIDER: S-EPMC10651869 | biostudies-literature | 2023 Feb
REPOSITORIES: biostudies-literature
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Project description:Patients with lymphoproliferative disorders such as chronic lymphocytic leukemia and mantle cell lymphoma (MCL) who are resistant to covalent Bruton tyrosine kinase inhibitors (cBTKis), especially if also venetoclax refractory, have an unmet therapeutic need. Pirtobrutinib, a noncovalent BTKi, achieves high response rates in patients who are refractory to cBTKi, regardless of mechanism of cBTKi resistance. This led to recent accelerated US Food and Drug Administration approval in MCL. The toxicity profile in early studies suggests suitability for use in combination approaches. We summarize existing preclinical and clinical data for pirtobrutinib.
| S-EPMC10646821 | biostudies-literature
Project description:PurposeWe hypothesized that inhibition and trapping of PARP1 alone would be sufficient to achieve antitumor activity. In particular, we aimed to achieve selectivity over PARP2, which has been shown to play a role in the survival of hematopoietic/stem progenitor cells in animal models. We developed AZD5305 with the aim of achieving improved clinical efficacy and wider therapeutic window. This next-generation PARP inhibitor (PARPi) could provide a paradigm shift in clinical outcomes achieved by first-generation PARPi, particularly in combination.Experimental designAZD5305 was tested in vitro for PARylation inhibition, PARP-DNA trapping, and antiproliferative abilities. In vivo efficacy was determined in mouse xenograft and PDX models. The potential for hematologic toxicity was evaluated in rat models, as monotherapy and combination.ResultsAZD5305 is a highly potent and selective inhibitor of PARP1 with 500-fold selectivity for PARP1 over PARP2. AZD5305 inhibits growth in cells with deficiencies in DNA repair, with minimal/no effects in other cells. Unlike first-generation PARPi, AZD5305 has minimal effects on hematologic parameters in a rat pre-clinical model at predicted clinically efficacious exposures. Animal models treated with AZD5305 at doses ≥0.1 mg/kg once daily achieved greater depth of tumor regression compared to olaparib 100 mg/kg once daily, and longer duration of response.ConclusionsAZD5305 potently and selectively inhibits PARP1 resulting in excellent antiproliferative activity and unprecedented selectivity for DNA repair deficient versus proficient cells. These data confirm the hypothesis that targeting only PARP1 can retain the therapeutic benefit of nonselective PARPi, while reducing potential for hematotoxicity. AZD5305 is currently in phase I trials (NCT04644068).
| S-EPMC9623235 | biostudies-literature
Project description:Abrogating tumor angiogenesis by inhibiting vascular endothelial growth factor receptor-2 (VEGFR2) has been established as a therapeutic strategy for treating cancer. However, because of their low selectivity, most small molecule inhibitors of VEGFR2 tyrosine kinase show unexpected adverse effects and limited anticancer efficacy. In the present study, we detailed the pharmacological properties of anlotinib, a highly potent and selective VEGFR2 inhibitor, in preclinical models. Anlotinib occupied the ATP-binding pocket of VEGFR2 tyrosine kinase and showed high selectivity and inhibitory potency (IC50 <1 nmol/L) for VEGFR2 relative to other tyrosine kinases. Concordant with this activity, anlotinib inhibited VEGF-induced signaling and cell proliferation in HUVEC with picomolar IC50 values. However, micromolar concentrations of anlotinib were required to inhibit tumor cell proliferation directly in vitro. Anlotinib significantly inhibited HUVEC migration and tube formation; it also inhibited microvessel growth from explants of rat aorta in vitro and decreased vascular density in tumor tissue in vivo. Compared with the well-known tyrosine kinase inhibitor sunitinib, once-daily oral dose of anlotinib showed broader and stronger in vivo antitumor efficacy and, in some models, caused tumor regression in nude mice. Collectively, these results indicate that anlotinib is a well-tolerated, orally active VEGFR2 inhibitor that targets angiogenesis in tumor growth, and support ongoing clinical evaluation of anlotinib for a variety of malignancies.
| S-EPMC5891194 | biostudies-literature
Project description:BTK plays a critical role in the B cell receptor mediated inflammatory signaling in the rheumatoid arthritis (RA). Through a rational design approach we discovered a highly selective and potent BTK kinase inhibitor (CHMFL-BTK-11) which exerted its inhibitory efficacy through a covalent bond with BTK Cys481. CHMFL-BTK-11 potently blocked the anti-IgM stimulated BCR signaling in the Ramos cell lines and isolated human primary B cells. It significantly inhibited the LPS stimulated TNF-α production in the human PBMC cells but only weakly affecting the normal PBMC cell proliferation. In the adjuvant-induced arthritis rat model, CHMFL-BTK-11 ameliorated the inflammatory response through blockage of proliferation of activated B cells, inhibition of the secretion of the inflammatory factors such as IgG1, IgG2, IgM, IL-6 and PMΦ phagocytosis, stimulation of secretion of IL-10. The high specificity of CHMFL-BTK-11 makes it a useful pharmacological tool to further detect BTK mediated signaling in the pathology of RA.
| S-EPMC5428509 | biostudies-literature
Project description:TL-895 (formerly known as M7583) is a potent, highly selective, adenosine triphosphate (ATP)-competitive, second-generation, irreversible inhibitor of Bruton's tyrosine kinase (BTK). We characterized its biochemical and cellular effects in in vitro and in vivo models. TL-895 was evaluated preclinically for potency against BTK using IC50 concentration-response curves; selectivity using a 270-kinase panel; BTK phosphorylation in Ramos Burkitt's lymphoma cells by ProteinSimple Wes analysis of one study; anti-proliferative effects in primary chronic lymphocytic leukemia (CLL) blasts; cell viability effects in diffuse large B-cell lymphoma (DLBCL) and mantle-cell lymphoma (MCL) cell lines; effects on antibody-dependent cell-mediated cytotoxicity (ADCC) from Daudi cells and chromium-51 release from human tumor cell lines; and efficacy in vivo using four MCL xenograft model and 21 DLBCL patient-derived xenograft (PDX) models (subtypes: 9 ABC, 11 GCB, 1 Unclassified). TL-895 was active against recombinant BTK (average IC50 1.5 nM) and inhibited only three additional kinases with IC50 within tenfold of BTK activity. TL-895 inhibited BTK auto-phosphorylation at the Y223 phosphorylation site (IC50 1-10 nM). TL-895 inhibited the proliferation of primary CLL blasts in vitro and inhibited growth in a subset of activated DLBCL and MCL cell lines. TL-895 inhibited the ADCC mechanism of therapeutic antibodies only at supra-clinical exposure levels. TL-895 significantly inhibited tumor growth in the Mino MCL xenograft model and in 5/21 DLBCL PDX models relative to vehicle controls. These findings demonstrate the potency of TL-895 for BTK and its efficacy in models of B-cell lymphoma despite its refined selectivity.
| S-EPMC10663516 | biostudies-literature
Project description:Covalent inhibitors of Bruton tyrosine kinase (BTK) have transformed the therapy of chronic lymphocytic leukemia (CLL), but continuous therapy has been complicated by the development of resistance. The most common resistance mechanism in patients whose disease progresses on covalent BTK inhibitors (BTKis) is a mutation in the BTK 481 cysteine residue to which the inhibitors bind covalently. Pirtobrutinib is a highly selective, noncovalent BTKi with substantial clinical activity in patients whose disease has progressed on covalent BTKi, regardless of BTK mutation status. Using in vitro ibrutinib-resistant models and cells from patients with CLL, we show that pirtobrutinib potently inhibits BTK-mediated functions including B-cell receptor (BCR) signaling, cell viability, and CCL3/CCL4 chemokine production in both BTK wild-type and C481S mutant CLL cells. We demonstrate that primary CLL cells from responding patients on the pirtobrutinib trial show reduced BCR signaling, cell survival, and CCL3/CCL4 chemokine secretion. At time of progression, these primary CLL cells show increasing resistance to pirtobrutinib in signaling inhibition, cell viability, and cytokine production. We employed longitudinal whole-exome sequencing on 2 patients whose disease progressed on pirtobrutinib and identified selection of alternative-site BTK mutations, providing clinical evidence that secondary BTK mutations lead to resistance to noncovalent BTKis.
| S-EPMC10202739 | biostudies-literature
Project description: Not available
| S-EPMC10539862 | biostudies-literature
Project description:ObjectiveB-cell antigen receptor (BCR) signaling is required to maintain the physiological functions of normal B cells and plays an important pathogenic role in B-cell malignancies. Bruton tyrosine kinase (BTK), a critical mediator of BCR signaling, is an attractive target for the treatment of B-cell malignancies. This study aimed to identify a highly potent and selective BTK inhibitor.MethodsHomogeneous time-resolved fluorescence assays were used to screen BTK inhibitors. Typhoon fluorescence imaging and Western blot analysis were used to confirm the effects of SY-1530 on the BCR signaling pathway. Additionally, the anti-tumor activities of SY-1530 were evaluated in TMD8 xenografts and spontaneous canine B-cell lymphoma.ResultsWe found a novel irreversible and non-competitive inhibitor of BTK, SY-1530, which provided dose-dependent and time-dependent inhibition. SY-1530 selectively bound to BTK rather than inducible T-cell kinase; consequently, it did not significantly affect T-cell receptor signaling and caused limited off-target effects. SY-1530 blocked the BCR signaling pathway through down-regulation of BTK activity, thus leading to impaired phosphorylation of BTK and its downstream kinases. Moreover, SY-1530 induced apoptosis in a caspase-dependent manner and efficaciously inhibited tumor growth in mouse xenograft models of B-cell malignancy (P < 0.001). SY-1530 also induced positive clinical responses in spontaneous canine B-cell lymphoma.ConclusionsSY-1530 is an irreversible and selective BTK inhibitor that shows inhibitory effects on B-cell malignancies by blocking the BCR signaling pathway. Therefore, it may be a promising therapeutic approach for the treatment of B-cell malignancies.
| S-EPMC9334755 | biostudies-literature
Project description:AbstractCovalent Bruton tyrosine kinase inhibitors (cBTKis), which bind to the BTK C481 residue, are now primary therapeutics for chronic lymphocytic leukemia (CLL). Alterations at C481, primarily C481S, prevent cBTKi binding and lead to the emergence of resistant clones. Pirtobrutinib is a noncovalent BTKi that binds to both wild-type (WT) and C481S-mutated BTK and has shown efficacy in BTK-WT and -mutated CLL patient groups. To compare baseline clinical, transcriptomic, and proteomic characteristics and their changes during treatment in these 2 groups, we used 67 longitudinal peripheral blood samples obtained during the first 3 cycles of treatment with pirtobrutinib from 18 patients with CLL (11 BTK-mutated, 7 BTK-WT) enrolled in the BRUIN (pirtobrutinib in relapsed or refractory B-cell malignancies) trial. Eastern Cooperative Oncology Group performance status, age, and Rai stage were similar in both groups. At baseline, lymph nodes were larger in the BTK-mutated cohort. All patients achieved partial remission within 4 cycles of pirtobrutinib. Lactate dehydrogenase and β2-microglobulin levels decreased in both cohorts after 1 treatment cycle. Expression analysis demonstrated upregulation of 35 genes and downregulation of 6 in the BTK-mutated group. Gene set enrichment analysis revealed that the primary pathways enriched in BTK-mutated cells were involved in cell proliferation, metabolism, and stress response. Pathways associated with metabolism and proliferation were downregulated in both groups during pirtobrutinib treatment. Proteomic data corroborated transcriptomic findings. Our data identified inherent differences between BTK-mutated and -WT CLL and demonstrated molecular normalization of plasma and omics parameters with pirtobrutinib treatment in both groups.
| S-EPMC11395759 | biostudies-literature
Project description:Background: Aberrant activation of RAS-RAF-MEK-ERK signaling pathway has been implicated in more than one-third of all malignancies. MEK inhibitors are promising therapeutic approaches to target this signaling pathway. Though four MEK inhibitors have been approved by FDA, these compounds possess either limited efficacy or unfavorable PK profiles with toxicity issues, hindering their broadly application in clinic. Our efforts were focused on the design and development of a novel MEK inhibitor, which subsequently led to the discovery of tunlametinib. Methods: This study verified the superiority of tunlametinib over the current MEK inhibitors in preclinical studies. The protein kinase selectivity activity of tunlametinib was evaluated against 77 kinases. Anti-proliferation activity was analyzed using the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) or (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS) assay. ERK and phospho-ERK levels were evaluated by Western blot analysis. Flow cytometry analysis was employed to investigate cell cycle and arrest. Cell-derived xenograft (CDX) and Patient-derived xenograft (PDX) models were used to evaluate the tumor growth inhibition. The efficacy of tunlametinib as monotherapy treatment was evaluated in KRAS/BRAF mutant or wild type xenograft model. Furthermore, the combination studies of tunlametinib with BRAF/KRASG12C/SHP2 inhibitors or chemotherapeutic agent were conducted by using the cell proliferation assay in vitro and xenograft models in vivo. Results: In vitro, tunlametinib demonstrated high selectivity with approximately 19-fold greater potency against MEK kinase than MEK162, and nearly 10-100-fold greater potency against RAS/RAF mutant cell lines than AZD6244. In vivo, tunlametinib resulted in dramatic tumor suppression and profound inhibition of ERK phosphorylation in tumor tissue. Mechanistic study revealed that tunlametinib induced cell cycle arrest at G0/G1 phase and apoptosis of cells in a dose-proportional manner. In addition, tunlametinib demonstrated a favorable pharmacokinetic profile with dose-proportionality and good oral bioavailability, with minimal drug exposure accumulation. Furthermore, tunlametinib combined with BRAF/KRASG12C/SHP2 inhibitors or docetaxel showed synergistically enhanced response and marked tumor inhibition. Conclusion: Tunlametinib exhibited a promising approach for treating RAS/RAF mutant cancers alone or as combination therapies, supporting the evaluation in clinical trials. Currently, the first-in-human phase 1 study and pivotal clinical trial of tunlametinib as monotherapy have been completed and pivotal trials as combination therapy are ongoing.
| S-EPMC10557067 | biostudies-literature