Long-term safety profile of tirabrutinib: final results of a Japanese Phase I study in patients with relapsed or refractory B-cell malignancies

Inhibitors of Bruton's tyrosine kinase as emerging therapeutic strategy in autoimmune diseases

Bruton's tyrosine kinase (BTK) is a cytoplasmic, non-receptor signal transducer, initially identified as an essential signaling molecule for B cells, with genetic mutations resulting in a disorder characterized by disturbed B cell and antibody development. Subsequent research revealed the critical role of BTK in the functionality of monocytes, macrophages and neutrophils. Various immune cells, among which B cells and neutrophils, rely on BTK activity for diverse signaling pathways downstream of multiple receptors, which makes this kinase an ideal target to treat hematological malignancies and autoimmune diseases. First-generation BTK inhibitors are already on the market to treat hematological disorders. It has been demonstrated that B cells and myeloid cells play a significant role in the pathogenesis of different autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus and primary Sjögren's syndrome. Consequently, second-generation BTK inhibitors are currently being developed to treat these disorders. Despite the acknowledged involvement of BTK in various cell types, the focus on B cells often overshadows its impact on innate immune cells. Among these cell types, neutrophils are often underestimated in the pathogenesis of autoimmune diseases. In this narrative review, the function of BTK in different immune cell subsets is discussed, after which an overview is provided of different upcoming BTK inhibitors tested for treatment of autoimmune diseases. Special attention is paid to BTK inhibition and its effect on neutrophil biology.

Structural optimization of pyrrolopyrimidine BTK inhibitors based on molecular simulation

CONTEXT

BTK is a critical regulator involved in the proliferation, differentiation, and apoptosis of B cells. BTK inhibitors can effectively alleviate various diseases such as tumors, leukemia, and asthma. During this study, a range of novel BTK inhibitors were designed using 3D-QSAR, molecular docking, and molecular dynamics (MD) simulation.

METHODS

We selected 41 pyrrolopyrimidine derivatives as BTK inhibitors to structure a 3D-QSAR model. Comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) were adopted to research the connection between the pharmacological activities and chemical structures of the compounds. The CoMFA model (q2 = 0.519, R2 = 0.971), CoMSIA model (q2 = 0.512, R2 = 0.990), and external validation demonstrated excellent predictive performance and reliability of the 3D-QSAR model. We designed eight novel molecules with higher inhibitory activities according to the three-dimensional equipotential fields and explored the interactions between the compounds and BTK by molecular docking, which showed that the novel molecules had higher binding affinities with BTK than the template molecule 18. Then, the results of molecular docking were further verified by MD simulation, which showed that amino acid residues such as Leu528, Val416, and Met477 played vital parts in the interaction, and the binding free energy analysis showed that the novel molecules had higher stability with BTK. Finally, the ADME/T properties were predicted for all of the novel compounds, and the results showed that the majority of them had favorable pharmacokinetic properties. Therefore, this study provides strong support for the development of novel BTK inhibitors.

Bruton tyrosine kinase inhibitors: can they be optimized for the treatment of neuroinflammatory disorders?

INTRODUCTION

Bruton's tyrosine kinase (BTK) is a multifaceted player of the immune system which has been involved in the survival of hematological malignancies but also in the pathogenesis of immune-mediated diseases. Oral BTK inhibitors (BTKi) have become a cornerstone for the treatment of patients with B-cell malignancies, and are under investigation for several immune-mediated diseases.

AREAS COVERED

We reviewed the biology of BTK and emerging data on BTKi in patients with neuroinflammatory disorders of both the peripheral and central nervous system.

EXPERT OPINION

We support the use of BTKi in relapsed/refractory patients with multiple sclerosis and anti-MAG antibody neuropathies. However, other immune-mediated neuroinflammatory disorders are likely to benefit from BTKi. Whether BTKi will improve the response rates than conventional therapies in previously untreated patients is unknown and will be assessed within future clinical trials. Furthermore, the availability of more selective BTKi, with less adverse events, will improve patients' tolerability and expand our treatment landscape.