Inhibitors targeting Bruton's tyrosine kinase in cancers: drug development advances

Kinase inhibitors: 20 years of success and many new challenges and recent trends in their patents

INTRODUCTION

Protein kinases (PKs) play key roles in cellular signaling and regulation cascades and therefore are listed among the most investigated enzymes with the intent to develop drugs that are able to modulate their catalytic features. Specifically, PKs are involved in chronic diseases of large impact in the society such as cancers and neurodegeneration. Since the approval of Fasudil for the management of cerebral vasospasm, frantic efforts are currently ongoing for the development of selective PK-modulating agents.

AREAS COVERED

A selection of the most relevant patents in the European Patent Office for biomedical innovation and/or industrial development covering the years 2020-2023 on PK modulators either of the antibody and small-molecule type is reported. In addition to the examined patents, we also reported the contributions claiming the use of antibody-targeted PKs for lab bench identification kits.

EXPERT OPINION

The field of PK modulators for biomedical purposes is particularly crowded with contributions, making it rich in valuable information for the development of potential drugs. An emerging frontier is represented by PK activators that aims to complement the use of PK inhibitors with the final intent of finely adjusting any PK-related disruption responsible for triggering any disease.

A real-world pharmacovigilance study of FDA Adverse Event Reporting System (FAERS) events for Bruton's tyrosine kinase inhibitors (BTKis) single and its combination therapy

BACKGROUND

Bruton's tyrosine kinase inhibitors (BTKis) are targeted treatments for B-cell tumors but have significant side effects. This study assesses and contrasts the side effects of BTKis alone and its four combination therapies.

RESEARCH DESIGN AND METHODS

The reporting odds ratio (ROR) was used to analyze the data on three BTKis monotherapies and combinations of ibrutinib with rituximab, obinutuzumab, venetoclax, and lenalidomide in the FDA Adverse Event Reporting System (FAERS) database up to December 2022.

RESULTS

We analyzed the top 20 PTs for each treatment regimen. In monotherapies, atrial fibrillation (ROR (95% CI): 9.88 (9.47-10.32)) in zanubrutinib and rash (6.97 (5.42-8.98)) in acalabrutinib had higher associations. In combinations, infection (6.86 (6.11-7.70)), atrial fibrillation (27.96 (22.61-34.58)) and myelosuppression (10.09 (8.89-11.46)) were vital signals when ibrutinib was combined with obinutuzumab, and pyrexia (4.22 (2.57-6.93)) had a high signal value when combined with lenalidomide. Hemorrhage had a lower signal value when combined with venetoclax compared to ibrutinib alone (2.50 (2.18-2.87) vs 3.60 (3.52-3.68)).

CONCLUSIONS

The ibrutinib-obinutuzumab combo has the highest risk of infection, atrial fibrillation, and myelosuppression, and the ibrutinib-lenalidomide combo has the highest risk of pyrexia. However, the ibrutinib-venetoclax combo has a lower risk of hemorrhage than monotherapy.

Analysis of ventricular arrhythmias and sudden death from prospective, randomized clinical trials of acalabrutinib

This analysis investigated the incidence of sudden deaths (SDs) and non-fatal and fatal ventricular arrhythmias (VAs) in five acalabrutinib clinical trials. In total, 1299 patients received acalabrutinib (exposure, 4568.4 patient-years). Sixteen (1.2%) patients experienced SD or VA (event rate, 0.350/100 patient-years). Non-fatal VAs occurred in 11 (0.8%) patients, nine (0.7%) of whom had premature ventricular contractions only. SD and fatal VAs occurred in five (0.4%) patients (event rate, 0.109/100 patient-years; median time to event: 46.2 months). SDs and VAs with acalabrutinib occurred at low rates, and there are insufficient data to point to an increased risk of SD or VA with acalabrutinib.

Bruton's tyrosine kinase inhibition limits endotoxic shock by suppressing IL-6 production by marginal zone B cells in mice

Sepsis is a systemic inflammatory response to a severe, life-threatening infection with organ dysfunction. Although there is no effective treatment for this fatal illness, a deeper understanding of the pathophysiological basis of sepsis and its underlying mechanisms could lead to the development of new treatment approaches. Here, we demonstrate that the selective Bruton's tyrosine kinase (Btk) inhibitor acalabrutinib augments survival rates in a lipopolysaccharide (LPS)-induced septic model. Our in vitro and in vivo findings both indicate that acalabrutinib reduces IL-6 production specifically in marginal zone B (MZ B) cells rather than in macrophages. Furthermore, Btk-deficient MZ B cells exhibited suppressed LPS-induced IL-6 production in vitro. Nuclear factor-kappa B (NF-κB) signaling, which is the downstream signaling cascade of Toll-like receptor 4 (TLR4), was also severely attenuated in Btk-deficient MZ B cells. These findings suggest that Btk blockade may prevent sepsis by inhibiting IL-6 production in MZ B cells. In addition, although Btk inhibition may adversely affect B cell maturation and humoral immunity, antibody responses were not impaired when acalabrutinib was administered for a short period after immunization with T-cell-independent (TI) and T-cell-dependent (TD) antigens. In contrast, long-term administration of acalabrutinib slightly impaired humoral immunity. Therefore, these findings suggest that Btk inhibitors may be a potential option for alleviating endotoxic shock without compromising humoral immunity and emphasize the importance of maintaining a delicate balance between immunomodulation and inflammation suppression.

Inflammation as a driver of hematological malignancies

Hematopoiesis is a tightly regulated process that produces all adult blood cells and immune cells from multipotent hematopoietic stem cells (HSCs). HSCs usually remain quiescent, and in the presence of external stimuli like infection or inflammation, they undergo division and differentiation as a compensatory mechanism. Normal hematopoiesis is impacted by systemic inflammation, which causes HSCs to transition from quiescence to emergency myelopoiesis. At the molecular level, inflammatory cytokine signaling molecules such as tumor necrosis factor (TNF), interferons, interleukins, and toll-like receptors can all cause HSCs to multiply directly. These cytokines actively encourage HSC activation, proliferation, and differentiation during inflammation, which results in the generation and activation of immune cells required to combat acute injury. The bone marrow niche provides numerous soluble and stromal cell signals, which are essential for maintaining normal homeostasis and output of the bone marrow cells. Inflammatory signals also impact this bone marrow microenvironment called the HSC niche to regulate the inflammatory-induced hematopoiesis. Continuous pro-inflammatory cytokine and chemokine activation can have detrimental effects on the hematopoietic system, which can lead to cancer development, HSC depletion, and bone marrow failure. Reactive oxygen species (ROS), which damage DNA and ultimately lead to the transformation of HSCs into cancerous cells, are produced due to chronic inflammation. The biological elements of the HSC niche produce pro-inflammatory cytokines that cause clonal growth and the development of leukemic stem cells (LSCs) in hematological malignancies. The processes underlying how inflammation affects hematological malignancies are still not fully understood. In this review, we emphasize the effects of inflammation on normal hematopoiesis, the part it plays in the development and progression of hematological malignancies, and potential therapeutic applications for targeting these pathways for therapy in hematological malignancies.

Discovery and Preclinical Pharmacology of NX-2127, an Orally Bioavailable Degrader of Bruton's Tyrosine Kinase with Immunomodulatory Activity for the Treatment of Patients with B Cell Malignancies

Bruton's tyrosine kinase (BTK), a member of the TEC family of kinases, is an essential effector of B-cell receptor (BCR) signaling. Chronic activation of BTK-mediated BCR signaling is a hallmark of many hematological malignancies, which makes it an attractive therapeutic target. Pharmacological inhibition of BTK enzymatic function is now a well-proven strategy for the treatment of patients with these malignancies. We report the discovery and characterization of NX-2127, a BTK degrader with concomitant immunomodulatory activity. By design, NX-2127 mediates the degradation of transcription factors IKZF1 and IKZF3 through molecular glue interactions with the cereblon E3 ubiquitin ligase complex. NX-2127 degrades common BTK resistance mutants, including BTKC481S. NX-2127 is orally bioavailable, exhibits in vivo degradation across species, and demonstrates efficacy in preclinical oncology models. NX-2127 has advanced into first-in-human clinical trials and achieves deep and sustained degradation of BTK following daily oral dosing at 100 mg.

Efficacy and Safety of BTKis in Central Nervous System Lymphoma: A Systematic Review and Meta-Analysis

BACKGROUND

This systematic review and meta-analysis aimed to evaluate the efficacy and safety of Bruton tyrosine kinase inhibitors (BTKis) for central nervous system lymphoma (CNSL).

METHODS

A systematic review was carried out to identify relevant studies from the PubMed, Embase, Cochrane Library, Web of Science, WanFang, CNKI, and CBM databases. The studies included patients with CNSL who received BTKis and reported the overall response (OR), complete remission (CR), and partial response (PR). An overall effect analysis was performed using STATA 15.0. A random-effects model was utilized to calculate the pooled rates, and 95% confidence intervals (CI) were determined for all outcomes.

RESULTS

A total of 21 studies involving 368 patients were included in the meta-analysis. For newly diagnosed CNSL, due to the small simple size, we conducted a quantitative description, and the ORR could reach up to 100%. For relapsed/refractory patients, the pooled ORR was 72% (95% CI: 64-80%, I2 = 54.89%, p = 0.00), with a pooled CR and PR of 43% (95% CI: 33-54%, I2 = 65.40%, p = 0.00) and 23% (95% CI: 13-35%, I2 = 78.05%, p = 0.00), respectively. Most adverse events were hematology-related and generally manageable.

CONCLUSION

BTKis showed acceptable efficacy and safety in treating patients with CNSL. However, large and well-designed trials are still required to confirm BTKis as a treatment for CNSL.

Cardiovascular Adverse Events Associated With Second-generation Bruton Tyrosine Kinase Inhibitor Therapy: A Systematic Review and Meta-analysis

PURPOSE

Cardiovascular adverse events (CVAEs) are common adverse effects of first-generation Bruton tyrosine kinase inhibitors (BTKis) and limit their use considerably. This led to the development of second-generation BTKis-acalabrutinib and zanubrutinib-which are more selective, potent, and presumed to have better safety profiles than the previous group of medications. However, there have been sporadic reports of CVAEs associated with second-generation BTKis in clinical practice. To address this issue, a comprehensive meta-analysis to pool the documented CVAEs was performed, including major hemorrhage, any bleeding, atrioventricular block, atrial fibrillation/flutter, pericardial effusion, pericarditis, heart failure, cardiac arrest, myocardial infarction, hypertension, hypotension, and stroke. This meta-analysis incorporated 8 studies. Among these, 6 were Phase III trials and 2 were Phase II trials. These studies collectively enrolled a total of 2938 patients.

METHODS

Multiple databases, including PubMed, MEDLINE, Cochrane Library, Scopus, and EMBASE, were systematically searched for relevant clinical trials from inception through January 14, 2023. The effect measure used was odds ratio (OR) and 95% CI.

FINDINGS

Of a total of 1774 studies identified during the initial database search, 8 were included in the meta-analysis. The incidence of overall and cardiovascular mortality was comparable between the 2 groups. There were no significant differences observed for cardiovascular mortality (OR = 0.36; 95% CI, 0.08-1.65; n = 2588; I2 = 45%; P = 0.19). Similar results were found for all-cause mortality (OR = 0.85; 95% CI, 0.67-1.07), any bleeding (OR = 1.90; 95% CI, 0.88-4.09), major bleeding (OR = 1.07; 95% CI, 0.65-1.76), atrioventricular block (OR = 0.74; 95% CI, 0.15-3.68), atrial fibrillation/flutter (OR = 0.74; 95% CI, 0.37-1.50), and other CVAEs associated with second-generation BTKis.

IMPLICATIONS

Based on the available evidence, there is no indication of worse cardiovascular outcomes or superiority of second-generation BTKis compared with standard treatments in terms of safety profile. However, additional large-scale controlled trials are needed to provide robust support for the superior tolerability of new-generation BTKis.

Treatment of Double-Refractory Chronic Lymphocytic Leukemia-An Unmet Clinical Need

Recent years have seen significant improvement in chronic lymphocytic leukemia (CLL) management. Targeting B-cell lymphoma (BCL-2) and Bruton's kinase (BTK) have become the main strategies to restrain CLL activity. These agents are generally well tolerated, but the discontinuation of these therapies happens due to resistance, adverse effects, and Richter's transformation. A growing population of patients who have previously used both BTK inhibitors and BCL2 suffer from the constriction of the following regimens. This review explores the resistance mechanisms for both ibrutinib and venetoclax. Moreover, we present innovative approaches evaluated for treating double-refractory CLL.

DCAF1-based PROTACs with activity against clinically validated targets overcoming intrinsic- and acquired-degrader resistance

Targeted protein degradation (TPD) mediates protein level through small molecule induced redirection of E3 ligases to ubiquitinate neo-substrates and mark them for proteasomal degradation. TPD has recently emerged as a key modality in drug discovery. So far only a few ligases have been utilized for TPD. Interestingly, the workhorse ligase CRBN has been observed to be downregulated in settings of resistance to immunomodulatory inhibitory drugs (IMiDs). Here we show that the essential E3 ligase receptor DCAF1 can be harnessed for TPD utilizing a selective, non-covalent DCAF1 binder. We confirm that this binder can be functionalized into an efficient DCAF1-BRD9 PROTAC. Chemical and genetic rescue experiments validate specific degradation via the CRL4DCAF1 E3 ligase. Additionally, a dasatinib-based DCAF1 PROTAC successfully degrades cytosolic and membrane-bound tyrosine kinases. A potent and selective DCAF1-BTK-PROTAC (DBt-10) degrades BTK in cells with acquired resistance to CRBN-BTK-PROTACs while the DCAF1-BRD9 PROTAC (DBr-1) provides an alternative strategy to tackle intrinsic resistance to VHL-degrader, highlighting DCAF1-PROTACS as a promising strategy to overcome ligase mediated resistance in clinical settings.

Bruton's Tyrosine Kinase Inhibitors with Distinct Binding Modes Reveal Differential Functional Impact on B-Cell Receptor Signaling

Small molecule inhibitors of Bruton's tyrosine kinase (BTK) have been approved for the treatment of multiple B-cell malignancies and are being evaluated for autoimmune and inflammatory diseases. Various BTK inhibitors (BTKi) have distinct potencies, selectivity profiles, and binding modes within the ATP-binding site. On the basis of the latter feature, BTKis can be classified into those that occupy the back-pocket, H3 pocket, and the hinge region only. Hypothesizing that differing binding modes may have differential impact on the B-cell receptor (BCR) signaling pathway, we evaluated the activities of multiple BTKis in B-cell lymphoma models in vitro and in vivo. We demonstrated that, although all three types of BTKis potently inhibited BTK-Y223 autophosphorylation and phospholipase C gamma 2 (PLCγ2)-Y1217 transphosphorylation, hinge-only binders were defective in inhibiting BTK-mediated calcium mobilization upon BCR activation. In addition, PLCγ2 activation was effectively blocked by back-pocket and H3 pocket binders but not by hinge-only binders. Further investigation using TMD8 cells deficient in Rac family small GTPase 2 (RAC2) revealed that RAC2 functioned as a bypass mechanism, allowing for residual BCR signaling and PLCγ2 activation when BTK kinase activity was fully inhibited by the hinge-only binders. These data reveal a kinase activity-independent function of BTK, involving RAC2 in transducing BCR signaling events, and provide mechanistic rationale for the selection of clinical candidates for B-cell lymphoma indications.

Investigating the ibrutinib resistance mechanism of L528W mutation on Bruton's tyrosine kinase via molecular dynamics simulations

Drug resistance to Bruton's Tyrosine Kinase (BTK) inhibitors presents a challenge in treating B-cell malignancies, and the mechanism behind drug resistance remains unclear. In this study, we focused on the BTK L528W mutation and investigated the underlying mechanisms of resistance to ibrutinib (including prototype and its active metabolite from, PCI-45227) using a combination of bioinformatics analysis, and molecular dynamics (MD) simulations. Protein stability of wild type (WT) BTK and L528W mutant was predicted using DUET, PoPMuSiC, and I-Mutant2.0. We performed MD simulations of six systems, apo-WT, metabolite-WT, prototype-WT and their mutants, to analyze the significant conformational and BTK-inhibitor binding affinity changes induced by the L528W mutation. Results show that the L528W mutation reduces the conformational stability of BTK compared to the WT. Principal component analysis (PCA) based free energy landscape (FEL) analysis shows that the L528W mutant ensemble tends to form more conformation clusters and exhibit higher levels of local minima than the WT counterpart. The interaction analysis reveal that the L528W mutation disrupts the strong hydrogen bond between Cys481 and inhibitors and reduces the number of hydrogen bonds between inhibitors and BTK in the L528W mutant complex structures compared to the WT. Porcupine plot analysis in association with cross-correlation analysis show the high-intensity flexible motion exhibited by the P-loop region. MM/GBSA calculations show that the L528W mutation in metabolite-BTK and prototype-BTK complexes increases binding free energy compared to the WT, with a reduction in binding affinity confirmed by per-residue energy decomposition. Specifically, the binding free energy increases from -57.86 kcal/mol to -48.26 kcal/mol for the metabolite-BTK complex and from -62.04 kcal/mol to -50.55 kcal/mol for the prototype-BTK complex. Overall, our study finds that the L528W mutation reduces BTK stability, decreases binding affinity, and leads to drug resistance and potential disease recurrence.

An effective treatment and suspicious adverse reaction to Ibrutinib in a patient diagnosed with splenic B-cell lymphoma/leukaemia with prominent nucleoli: A first case report

RATIONALE

Splenic B-cell lymphoma/leukemia with prominent nucleoli (SBLPN) is a new classification, which is so rare that it lacks clinical data.

PATIENT CONCERNS

An increased proportion of prolymphocytes (84%) in the bone marrow smear. Whole exon sequence analysis revealed a TP53 mutation.

DIAGNOSES

Combining the clinical features with laboratory test results led to a diagnosis of SBLPN which was made according to the 5th edition of the WHO classification of hematolymphoid tumors, although the patient was diagnosed with B-PLL when guided by the 4th edition of the WHO classification.

INTERVENTIONS

The use of Ibrutinib as an effective treatment.

OUTCOMES

The patient was in complete remission after 5 months of Ibrutinib and then died of sudden aortic dissection.

LESSONS

Ibrutinib was an effective regimen for SBLPN. Aortic dissection might be considered as a suspicious adverse reaction to Ibrutinib.

Resisting the Resistance: Navigating BTK Mutations in Chronic Lymphocytic Leukemia (CLL)

Bruton's tyrosine kinase (BTK) plays a key role in the B-cell receptor (BCR) signaling pathway and confers anti-apoptotic and proliferative properties to malignant B-cells in chronic lymphocytic leukemia (CLL). Small molecule BTK inhibitors were designed to bind BTK's active site and block downstream signaling. These drugs have now been used in the treatment of thousands of patients with CLL, the most common form of leukemia in the western hemisphere. However, adverse effects of early generations of BTK inhibitors and resistance to treatment have led to the development of newer, more selective and non-covalent BTK inhibitors. As the use of these newer generation BTK inhibitors has increased, novel BTK resistance mutations have come to light. This review aims to discuss previously known and novel BTK mutations, their mechanisms of resistance, and their relationship with patient treatment. Also discussed here are future studies that are needed to investigate the underlying cause allowing these mutations to occur and how they incite resistance. New treatments on the horizon that attempt to maneuver around these resistance mutations can be met with new resistance mutations, creating an unmet need for patients with CLL. Novel therapies and combinations that address all forms of resistance are discussed.

A novel Bruton's tyrosine kinase inhibitor JDB175 shows potent efficacy to suppress central nervous system lymphoma

Patients with central nervous system (CNS) lymphoma face limited treatment options and poor treatment outcomes, emphasizing the urgent need for effective therapeutic strategies. One limiting factor contributing to the suboptimal efficacy is the inadequate penetration of most treatment drugs across the blood-brain barrier (BBB). Recent insights into the pathophysiology of CNS lymphoma have identified the Bruton's tyrosine kinase (BTK) signaling pathway as a potential target. Some clinical trials have shown impressive responses to BTK inhibitors in CNS lymphoma. However, currently approved BTK inhibitors have low BBB penetration rates, limiting their efficacy. In this study, we discovered that JDB175, a novel and highly selective BTK inhibitor, exhibits excellent BBB penetration capabilities and demonstrates favorable activity in a mouse model of CNS lymphoma while showing no significant signs of toxicity. JDB175 effectively inhibits the BTK signaling pathway in human lymphoma cells, suppressing their proliferation, inducing cell cycle arrest, and promoting apoptosis. The significance of this study lies in addressing the critical unmet medical need for effective treatments for CNS lymphoma. This finding indicates a promising avenue for improved treatments in CNS lymphoma, potentially opening doors for further clinical investigation and therapeutic advancements.

miR-28-based combination therapy impairs aggressive B cell lymphoma growth by rewiring DNA replication

Diffuse large B cell lymphoma (DLBCL) is the most common aggressive B cell lymphoma and accounts for nearly 40% of cases of B cell non-Hodgkin lymphoma. DLBCL is generally treated with R-CHOP chemotherapy, but many patients do not respond or relapse after treatment. Here, we analyzed the therapeutic potential of the tumor suppressor microRNA-28 (miR-28) for DLBCL, alone and in combination with the Bruton's tyrosine kinase inhibitor ibrutinib. Combination therapy with miR-28 plus ibrutinib potentiated the anti-tumor effects of monotherapy with either agent by inducing a specific transcriptional cell-cycle arrest program that impairs DNA replication. The molecular actions of miR-28 and ibrutinib synergistically impair DNA replication by simultaneous inhibition of origin activation and fork progression. Moreover, we found that downregulation of the miR-28-plus-ibrutinib gene signature correlates with better survival of ABC-DLBCL patients. These results provide evidence for the effectiveness of a new miRNA-based ibrutinib combination therapy for DLBCL and unveil the miR-28-plus-ibrutinib gene signature as a new predictor of outcome in ABC-DLBCL patients.

Efficacy and safety of new-generation Bruton tyrosine kinase inhibitors in chronic lymphocytic leukemia/small lymphocytic lymphoma: a systematic review and meta-analysis

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is a type of mature B lymphocyte clonal proliferative tumor with a specific immunophenotype. Bruton tyrosine kinase inhibitors (BTKi) have been approved for the treatment of CLL/SLL. However, the efficacy and safety of new-generation BTKi-based regimens have not been systematically studied. In this systematic review, we evaluated the efficacy and safety of new-generation BTKi-based regimens for the treatment of patients with CLL/SLL. A comprehensive search on PubMed, Embase, Cochrane Library, and ClinicalTrials.gov. up to January 31, 2023, was conducted by us. Studies reporting data on CLL/SLL patients treated with new-generation BTKi were included. We assessed the overall response rate (ORR), complete response (CR) rate, and 24-month OS/PFS rates for efficacy analysis. For safety analysis, we evaluated the incidence of grade ≥ 3 adverse events (AEs). The meta-analysis included twenty studies. The pooled ORR for new-generation BTKi was 92% (95% CI, 89-95%, I2 = 80.68%, P = 0.00), while the pooled CR rate was 10% (95% CI, 6-14%, I2 = 88.11%, P = 0.00). Research has found that the new-generation BTKi-based therapy had higher efficacy under the following treatment conditions: < 65 years old, treatment-naive (TN)-CLL, and BTKi combination therapy. The ORR/CR rates and 24-month OS/PFS rates of BTKi combination therapy were higher than that of BTKi monotherapy. Compared to acalabrutinib monotherapy, zanubrutinib monotherapy demonstrated higher ORR/CR rates and 24-month OS/PFS rates. Common grade ≥ 3 AEs included cytopenia and hypertension. The new-generation BTKi-based therapy has good tolerance and provides incremental benefits for CLL/SLL patients. Despite the superior efficacy of BTKi combination therapy compared to monotherapy, its AEs rates are relatively high. Compared to acalabrutinib, Zanubrutinib may be the preferred monotherapy for CLL. However, randomized-controlled studies are still needed.

AI & experimental-based discovery and preclinical IND-enabling studies of selective BMX inhibitors for development of cancer therapeutics

The current work aims to design and provide a preliminary IND-enabling study of selective BMX inhibitors for cancer therapeutics development. BMX is an emerging target, more notably in oncological and immunological diseases. In this work, we have employed a predictive AI-based platform to design the selective inhibitors considering the novelty, IP prior protection, and drug-likeness properties. Furthermore, selected top candidates from the initial iteration of the design were synthesized and chemically characterized utilizing 1H NMR and LC-MS. Employing a panel of biochemical (enzymatic) and cancer cell lines, the selected molecules were tested against these assays. In addition, we used artificial intelligence to predict and evaluate several critical IND-focused physicochemical and pharmacokinetics values of the selected molecules. A secondary objective of the current work was also to validate the sole role of BMX in animal models known to be mediated by BMX. More than 50 molecules were designed in the present study employing five novel discovered scaffolds. Two molecules were nominated for further IND-focused studies. Compound II showed promising in-vitro activity against BMX in both enzymatic assays compared to other kinases and in cancer cell lines with known BMX overexpression. Interestingly, compound II showed very favorable physicochemical and pharmacokinetics properties as predicted by the used platforms. The animal study further confirmed the sole role of BMX in the disease model. The current work provides promising data on a selective BMX inhibitor as a potential lead for therapeutics development, and the asset is currently in the optimization stage. Notably, the current study shows a framework for a combined approach employing both AI and experimentation that can be used by academic labs in their research programs to more streamline programs into IND-focused to be bridged easily for further clinical development with industrial partners.

A prediction model for severe hematological toxicity of BTK inhibitors

Bruton's tyrosine kinase inhibitor (BTKi) has revolutionized the treatment of B-cell lymphomas. However, BTKi-related hematological toxicity hinders treatment continuity and may further affect clinical efficacy. To identify risk factors and predict the likelihood of BTKi-related hematological toxicities, we constructed and validated a prediction model for severe hematological toxicity of BTKi. Approved by the hospital medical science research ethics committee (No. M2022427), we collected real-world data in patients treated with BTKi from a Lymphoma Research Center in China. The outcome of interest was severe hematological toxicity caused by BTKi. 36 candidate variables were categorized into demographics, diagnostic and treatment information, laboratory data, and medical history. The study sample was randomly divided into training (70%) and validation (30%) sets. We developed and compared the performance of various modelling methods, including decision tree (DT), random forest (RF), gradient boosting decision tree (GBDT), extreme gradient boosting (XGBoost), light gradient boosting machine (LightGBM), and logistic regression (LR). Finally, we constructed a Web-calculator of the optimal model to estimate the risk of hematological toxicity. This study was designed, conducted and reported strictly in compliance with the TRIPOD checklist. Data from a total 121 patients were included [median age, 65 years (range, 56-73 years); 74 (61.15%) men; 47 (38.84%) severe hematological toxicity]. The XGBoost model demonstrated better overall properties than other models, achieving high discrimination (AUC: 0.671; accuracy: 0.730; specificity: 0.913) and clinical benefit. The following 10 variables were used to develop the XGBoost model: white blood cell count (WBC), neutrophil count (Neut), red blood cell count (RBC), platelet count (PLT), fibrinogen (Fib), total protein (TP), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), gender and type of BTKi. SHAP values demonstrated insightful associations between these variables and hematological toxicity. Finally, to facilitate clinical and research use, we also deploy the XGBoost model on a web-calculator for free access. The XGBoost model with promising accuracy was developed to predict the severe hematological toxicity of BTKi. It helps to strengthen the proactive monitoring and management of patients with hematological toxicity, and thus achieve long-term continuous BTKi treatment.

Drug-drug interactions and dose management of BTK inhibitors when initiating nirmatrelvir/ritonavir (paxlovid) based on physiologically-based pharmacokinetic models

OBJECTIVE

Co-administration of Bruton's tyrosine kinase (BTK) inhibitors with nirmatrelvir/ritonavir is challenging because of potential drug-drug interactions (DDIs). However, clinical trials specifically evaluating such DDIs are absent. To evaluate and quantify the DDIs between them and provide rational dose management strategies of BTK inhibitors, we conducted this study using physiologically-based pharmacokinetic (PBPK) models.

METHODS

Physicochemical properties and pharmacokinetic parameters were acquired from the published literature and databases. The PBPK models were developed using Simcyp® software. These models were validated by comparing with published literature values. The successfully validated PBPK models were used to simulate the plasma concentration-time profiles and DDIs in a virtual healthy population receiving BTK inhibitors alone or with ritonavir.

RESULTS

Simulated plasma concentration-time profiles and pharmacokinetic parameters of each drug were in agreement with clinically observed values from literatures. Ritonavir increased ibrutinib maximum plasma concentration (Cmax) and the area under plasma concentration-time curve (AUC) 33- and 53.88-fold, respectively, increased zanubrutinib Cmax and AUC 2.57- and 3.18-fold, respectively, and increased acalabrutinib Cmax and AUC 3.85- and 6.54-fold, respectively. Based on our simulations, dose-adjustment strategies may consist of ibrutinib at 25 mg q48h, zanubrutinib at 80 mg twice-daily and acalabrutinib at 25 mg twice-daily with nirmatrelvir/ritonavir.

CONCLUSIONS

The PBPK models predicted the in vivo pharmacokinetics and the DDIs of BTK inhibitors and ritonavir. The prospective simulations not only provided scientific evidence regarding rational dosing management strategies when initiating nirmatrelvir/ritonavir therapy but also provided a reference for the design of clinical DDIs study that may save resources and time.

SUMMARY

Paxlovid could increase Cmax and AUC0-τ of BTK inhibitors (ibrutinib, zanubrutinib and acalabrutinib), and dose adjustment strategy of ibrutinib (25 mg q48h), zanubrutinib (80 mg q12h) and acalabrutinib (25 mg q12h) should be considered when combination with nirmatrelvir/ritonavir.

Recent research of BTK inhibitors: Methods of structural design, pharmacological activities, manmade derivatives and structure-activity relationship

Protein kinases constitute the largest group within the kinase family, and mutations and translocations of protein kinases due to genetic alterations are intimately linked to the pathogenesis of numerous diseases. Bruton's tyrosine kinase (BTK) is a member of the protein kinases and plays a pivotal role in the development and function of B cells. BTK belongs to the tyrosine TEC family. The aberrant activation of BTK is closely associated with the pathogenesis of B-cell lymphoma. Consequently, BTK has always been a critical target for treating hematological malignancies. To date, two generations of small-molecule covalent irreversible BTK inhibitors have been employed to treat malignant B-cell tumors, and have exhibited clinical efficacy in hitherto refractory diseases. However, these drugs are covalent BTK inhibitors, which inevitably lead to drug resistance after prolonged use, resulting in poor tolerance in patients. The third-generation non-covalent BTK inhibitor Pirtobrutinib has obtained approval for marketing in the United States, thereby circumventing drug resistance caused by C481 mutation. Currently, enhancing safety and tolerance constitutes the primary issue in developing novel BTK inhibitors. This article systematically summarizes recently discovered covalent and non-covalent BTK inhibitors and classifies them according to their structures. This article also provides a detailed discussion of binding modes, structural features, pharmacological activities, advantages and limitations of typical compounds within each structure type, providing valuable references and insights for developing safer, more effective and more targeted BTK inhibitors in future studies.

Structure of BTK kinase domain with the second-generation inhibitors acalabrutinib and tirabrutinib

Bruton's tyrosine kinase (BTK) is the target of the therapeutic agent, Ibrutinib, that treats chronic lymphocyte leukemia (CLL), mantle cell lymphoma (MCL) and other B cell malignancies. Ibrutinib is a first in class, covalent BTK inhibitor that limits B-cell survival and proliferation. Designing new inhibitors of BTK has been an important objective for advancing development of improved therapeutic agents against cancer and autoimmune disorders. Based on the success of Ibrutinib, several second-generation irreversible BTK inhibitors have been developed that exhibit fewer off-target effects. However, the binding-mode and their interaction with Btk have not been experimentally determined and evaluated at atomic resolution. Here we determined the first crystal structure of the BTK kinase domain in complex with acalabrutinib. In addition, we report a structure of the BTK/tirabrutinib complex and compare these structures with previously solved structures. The structures provide insight in the superior selectivity reported for acalabrutinb and guide future BTK inhibitor development.

Influence of Bruton's Tyrosine Kinase (BTK) on Epithelial-Mesenchymal Transition (EMT) Processes and Cancer Stem Cell (CSC) Enrichment in Head and Neck Squamous Cell Carcinoma (HNSCC)

Constitutively active kinases play a crucial role in carcinogenesis, and their inhibition is a common target for molecular tumor therapy. We recently discovered the expression of two oncogenic isoforms of Bruton's Tyrosine Kinase (BTK) in head and neck squamous cell carcinoma (HNSCC), Btk-p80 and BTK-p65. However, the precise role of BTK in HNSCC remains unclear. Analyses of a tissue microarray containing benign and malignant as well as inflammatory tissue samples of the head and neck region revealed the preferential expression of BTK-p80 in malignant tissue, whereas BTK-p65 expression was confirmed in over 80% of analyzed metastatic head and neck tumor cases. Therefore, processes associated with metastasis, like cancer stem cell (CSC) enrichment and the epithelial-mesenchymal transition (EMT), which in turn depend on an appropriate cytokine milieu, were analyzed. Treatment of HNSCC-derived cell lines cultured under 3D conditions with the BTK inhibitor AVL-292 caused reduced sphere formation, which was accompanied by reduced numbers of ALDH1A1+ CSCs as well as biological changes associated with the EMT. Moreover, we observed reduced NF-κB expression as well as altered NF-κB dependent pro-tumorigenic and EMT-associated cytokine release of IL-6, IFNγ, and TNFα when BTK activity was dampened. Therefore, an autocrine regulation of the oncogenic BTK-dependent process in HNSCC can be suggested, with BTK inhibition expected to be an effective treatment option for HNSCC.

Orelabrutinib for the treatment of relapsed or refractory MCL: a phase 1/2, open-label, multicenter, single-arm study

Relapsed or refractory (r/r) mantle cell lymphoma (MCL) is an aggressive B-cell malignancy with a poor prognosis. Bruton tyrosine kinase (BTK) is a mediator of B-cell receptor signaling and is associated with the development of B-cell lymphomas. Patients with r/r MCL were enrolled in this phase 1/2 study and treated with orelabrutinib, a novel, highly selective BTK inhibitor. The median number of prior regimens was 2 (range, 1-4). The median age was 62 years (range, 37-73 years). Eligible patients received oral orelabrutinib 150 mg once daily (n = 86) or 100 mg twice daily (n = 20) until disease progression or unacceptable toxicity. A dose of 150 mg once daily was chosen as the preferred recommended phase 2 dose. After a median follow-up duration of 23.8 months, the overall response rate was 81.1%, with 27.4% achieving a complete response and 53.8% achieving a partial response. The median duration of response and progression-free survival were 22.9 and 22.0 months, respectively. The median overall survival (OS) was not reached, and the rate of OS at 24 months was 74.3%. Adverse events (AEs) occurring in >20% of patients were thrombocytopenia (34.0%), upper respiratory tract infection (27.4%), and neutropenia (24.5%). Grade ≥3 AEs were infrequent and most commonly included thrombocytopenia (13.2%), neutropenia (8.5%), and anemia (7.5%). Three patients discontinued treatment because of treatment-related adverse events (TRAEs), but no fatal TRAEs were reported. Orelabrutinib showed substantial efficacy and was well tolerated in patients with r/r MCL. This trial was registered at www.clinicaltrials.gov as #NCT03494179.

Susceptibility to Cryptococcus neoformans Infection with Bruton's Tyrosine Kinase Inhibition

Patients receiving the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib have an increased likelihood of fungal infections. The objectives of this study were to determine if Cryptococcus neoformans infection severity was isolate dependent with BTK inhibition and whether blocking BTK impacted infection severity in a mouse model. We compared four clinical isolates from patients on ibrutinib to virulent (H99) and avirulent (A1-35-8) reference strains. BTK knockout (KO) and wild-type (WT) C57 mice and WT CD1 mice were infected by intranasal (i.n.), oropharyngeal aspiration (OPA), and intravenous (i.v.) routes. Infection severity was assessed by survival and fungal burden (CFU per gram of tissue). Ibrutinib (25 mg/kg) or vehicle was administered daily through intraperitoneal injections. In the BTK KO model, no isolate-dependent effect on fungal burden was observed, and infection severity was not significantly different from that of the WT with i.n., OPA, and i.v. routes. Ibrutinib treatment did not impact infection severity. However, when the four clinical isolates were compared to H99, two of these isolates were less virulent, with significantly longer survival and reduced rates of brain infection. In conclusion, C. neoformans infection severity in the BTK KO model does not appear to be isolate dependent. BTK KO and ibrutinib treatment did not result in significantly different infection severities. However, based on repeated clinical observations of increased susceptibility to fungal infections with BTK inhibitor therapy, further work is needed to optimize a mouse model with BTK inhibition to better understand the role that this pathway plays in susceptibility to C. neoformans infection.

The preclinical discovery and development of orelabrutinib as a novel treatment option for B-cell lymphoid malignancies

INTRODUCTION

Bruton's tyrosine kinase (BTK) inhibitors have recently been approved for clinical use against several B-cell indolent lymphoid malignancies, both as single agents or in combination. One second-generation BTK inhibitor that is being developed for the treatment of B-cell hematological malignancies, as well as for autoimmune disorders, is orelabrutinib.

AREAS COVERED

This paper reviews recent developments in the use of orelabrutinib against B-cell indolent lymphoid malignancies such as chronic lymphocytic leukemia, mantle cell lymphoma, diffuse large B-cell lymphoma, Waldenstrom macroglobulinemia and central nervous system lymphoma. Google Scholar and PubMed were initially searched for articles, and the corpus of articles was broadened by reviewing the references of the identified papers. All were in English. The corpus comprised papers from 2016 to April 2023. In addition, a manual search was performed of conference proceedings from the last five years of The American Society of Hematology, American Society of Clinical Oncology and the European Hematology Association.

EXPERT OPINION

Orelabrutinib is an active drug in indolent and aggressive B-cell lymphoid malignancies. It demonstrates high selectivity, good efficacy and an excellent safety profile. Nevertheless, further clinical trials are required to optimize its use. In addition, several other highly selective BTK inhibitors are being examined in early-phase studies.

Pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine Sulfonamides as an Important Scaffold for Anticancer Drug Discovery-In Vitro and In Silico Evaluation

Pyrazolo[4,3-e]tetrazolo[1,5-b][1,2,4]triazine sulfonamides (MM-compounds) are a relatively new class of heterocyclic compounds that exhibit a wide variety of biological actions, including anticancer properties. Here, we used caspase enzyme activity assays, flow cytometry analysis of propidium iodide (PI)-stained cells, and a DNA laddering assay to investigate the mechanisms of cell death triggered by the MM-compounds (MM134, -6, -7, and -9). Due to inconsistent results in caspase activity assays, we have performed a bromodeoxyuridine (BrdU) incorporation assay, colony formation assay, and gene expression profiling. The compounds' cytotoxic and pro-oxidative properties were also assessed. Additionally, computational studies were performed to demonstrate the potential of the scaffold for future drug discovery endeavors. MM-compounds exhibited strong micromolar (0.06-0.35 µM) anti-proliferative and pro-oxidative activity in two cancer cell lines (BxPC-3 and PC-3). Activation of caspase 3/7 was observed following a 24-h treatment of BxPC-3 cells with IC₅₀ concentrations of MM134, -6, and -9 compounds. However, no DNA fragmentation characteristics for apoptosis were observed in the flow cytometry and DNA laddering analysis. Gene expression data indicated up-regulation of BCL10, GADD45A, RIPK2, TNF, TNFRSF10B, and TNFRSF1A (TNF-R1) following treatment of cells with the MM134 compound. Moreover, in silico studies indicated AKT2 kinase as the primary target of compounds. MM-compounds exhibit strong cytotoxic activity with pro-oxidative, pro-apoptotic, and possibly pro-necroptotic properties that could be employed for further drug discovery approaches.

Development and application of nanomaterials, nanotechnology and nanomedicine for treating hematological malignancies

Hematologic malignancies (HMs) pose a serious threat to patients' health and life, and the five-year overall survival of HMs remains low. The lack of understanding of the pathogenesis and the complex clinical symptoms brings immense challenges to the diagnosis and treatment of HMs. Traditional therapeutic strategies for HMs include radiotherapy, chemotherapy, targeted therapy and hematopoietic stem cell transplantation. Although immunotherapy and cell therapy have made considerable progress in the last decade, nearly half of patients still relapse or suffer from drug resistance. Recently, studies have emerged that nanomaterials, nanotechnology and nanomedicine show great promise in cancer therapy by enhancing drug targeting, reducing toxicity and side effects and boosting the immune response to promote durable immunological memory. In this review, we summarized the strategies of recently developed nanomaterials, nanotechnology and nanomedicines against HMs and then proposed emerging strategies for the future designment of nanomedicines to treat HMs based on urgent clinical needs and technological progress.

First line therapy of CLL

Chronic lymphocytic leukemia (CLL) is one of the most frequent types of leukemia. It typically occurs in elderly patients and has a highly variable clinical course. Only patients with active or symptomatic disease or with advanced Binet or Rai stages require therapy. When treatment is indicated, several therapeutic options exist today and need to be selected. A combination of the BCL2 inhibitor venetoclax with obinutuzumab, monotherapy with inhibitors of Bruton tyrosine kinase (BTK) such as ibrutinib, acalabrutinib or zanubrutinib, while chemoimmunotherapy (CIT) is disappearing as a therapeutic option.

A Phase 1 First-in-Human Pharmacokinetic and Pharmacodynamic Study of JNJ-64264681, a Covalent Inhibitor of Bruton's Tyrosine Kinase

JNJ-64264681 is an irreversible covalent inhibitor of Bruton's tyrosine kinase. This phase 1, first-in-human, 2-part (single-ascending dose [SAD]; multiple-ascending dose [MAD]) study evaluated the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD; Bruton's tyrosine kinase occupancy [BTKO]) of JNJ-64264681 oral solution in healthy participants. For SAD (N = 78), 6 increasing doses of JNJ-64264681 (4-400 mg) or placebo were evaluated in fasted males. The effects of sex, food, and a capsule formulation were evaluated in separate cohorts. For MAD (N = 27), sequential cohorts of male and female participants received 36/100/200 mg JNJ-64264681 once daily for 10 days. JNJ-64264681 exposure (peak concentration; area under the concentration-time curve) was less than dose proportional from 4 mg to 36 mg. Dose-normalized area under the concentration-time curves following the 36 mg and 100 mg doses were generally similar. The mean terminal half-life was 1.6-13.2 hours. With multiple doses, steady state was achieved by day 2. A semimechanistic PK/PD model was developed using the first 5 SAD cohorts' data to predict %BTKO in MAD cohorts. PK/PD model guided dose-escalation, and all participants in the 200/400 mg single-dose cohorts achieved ≥90% BTKO at 4 hours after dosing (peak) with prolonged occupancy. As BTKO data became available from MAD cohorts, it was found that observed BTKO data were consistent with model predictions. JNJ-64264681 showed no safety signals of concern. Overall, safety, tolerability, PK, BTKO, and PK/PD modeling guided the rationale for dose selection for the subsequent first-in-patient lymphoma studies.

Bruton tyrosine kinase inhibitors for multiple sclerosis

Current therapies for multiple sclerosis (MS) reduce both relapses and relapse-associated worsening of disability, which is assumed to be mainly associated with transient infiltration of peripheral immune cells into the central nervous system (CNS). However, approved therapies are less effective at slowing disability accumulation in patients with MS, in part owing to their lack of relevant effects on CNS-compartmentalized inflammation, which has been proposed to drive disability. Bruton tyrosine kinase (BTK) is an intracellular signalling molecule involved in the regulation of maturation, survival, migration and activation of B cells and microglia. As CNS-compartmentalized B cells and microglia are considered central to the immunopathogenesis of progressive MS, treatment with CNS-penetrant BTK inhibitors might curtail disease progression by targeting immune cells on both sides of the blood-brain barrier. Five BTK inhibitors that differ in selectivity, strength of inhibition, binding mechanisms and ability to modulate immune cells within the CNS are currently under investigation in clinical trials as a treatment for MS. This Review describes the role of BTK in various immune cells implicated in MS, provides an overview of preclinical data on BTK inhibitors and discusses the (largely preliminary) data from clinical trials.

Recent Advances in Covalent Drug Discovery

In spite of the increasing number of biologics license applications, the development of covalent inhibitors is still a growing field within drug discovery. The successful approval of some covalent protein kinase inhibitors, such as ibrutinib (BTK covalent inhibitor) and dacomitinib (EGFR covalent inhibitor), and the very recent discovery of covalent inhibitors for viral proteases, such as boceprevir, narlaprevir, and nirmatrelvir, represent a new milestone in covalent drug development. Generally, the formation of covalent bonds that target proteins can offer drugs diverse advantages in terms of target selectivity, drug resistance, and administration concentration. The most important factor for covalent inhibitors is the electrophile (warhead), which dictates selectivity, reactivity, and the type of protein binding (i.e., reversible or irreversible) and can be modified/optimized through rational designs. Furthermore, covalent inhibitors are becoming more and more common in proteolysis, targeting chimeras (PROTACs) for degrading proteins, including those that are currently considered to be 'undruggable'. The aim of this review is to highlight the current state of covalent inhibitor development, including a short historical overview and some examples of applications of PROTAC technologies and treatment of the SARS-CoV-2 virus.

The magic of small-molecule drugs during ex vivo expansion in adoptive cell therapy

In the past decades, advances in the use of adoptive cellular therapy to treat cancer have led to unprecedented responses in patients with relapsed/refractory or late-stage malignancies. However, cellular exhaustion and senescence limit the efficacy of FDA-approved T-cell therapies in patients with hematologic malignancies and the widespread application of this approach in treating patients with solid tumors. Investigators are addressing the current obstacles by focusing on the manufacturing process of effector T cells, including engineering approaches and ex vivo expansion strategies to regulate T-cell differentiation. Here we reviewed the current small-molecule strategies to enhance T-cell expansion, persistence, and functionality during ex vivo manufacturing. We further discussed the synergistic benefits of the dual-targeting approaches and proposed novel vasoactive intestinal peptide receptor antagonists (VIPR-ANT) peptides as emerging candidates to enhance cell-based immunotherapy.

How We Manage Patients with Indolent B-Cell Malignancies on Bruton's Tyrosine Kinase Inhibitors: Practical Considerations for Nurses and Pharmacists

The most common forms of B-cell malignancy, non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL), have seen a drastic shift in the treatment landscape over the last two decades with the introduction of targeted agents. Among them are Bruton's tyrosine kinase (BTK) inhibitors, which have demonstrated excellent efficacy in indolent B-cell NHLs and CLL. Although BTK inhibitors are generally thought to be more tolerable than chemoimmunotherapy, they are associated with a unique safety profile including varying rates of rash, diarrhea, musculoskeletal events, cardiovascular events, and bleeding. Ibrutinib was the first BTK inhibitor to gain a Health Canada indication, followed by second-generation BTK inhibitors acalabrutinib and zanubrutinib, which have better safety profiles compared to ibrutinib, likely due to their improved selectivity for BTK. As BTK inhibitors are oral agents given continuously until disease progression, long-term adverse event (AE) monitoring and management as well as polypharmacy considerations are important for maintaining patient quality of life. This paper intends to serve as a reference for Canadian nurses and pharmacists on dosing, co-administration, and AE management strategies when caring for patients with indolent B-cell NHL or CLL being treated with BTK inhibitors.

Established and Emerging Cancer Therapies and Cardiovascular System: Focus on Hypertension-Mechanisms and Mitigation

Cardiovascular disease and cancer are 2 of the leading causes of death worldwide. Although improvements in outcomes have been noted for both disease entities, the success of cancer therapies has come at the cost of at times very impactful adverse events such as cardiovascular events. Hypertension has been noted as both, a side effect as well as a risk factor for the cardiotoxicity of cancer therapies. Some of these dynamics are in keeping with the role of hypertension as a cardiovascular risk factor not only for heart failure, but also for the development of coronary and cerebrovascular disease, and kidney disease and its association with a higher morbidity and mortality overall. Other aspects such as the molecular mechanisms underlying the amplification of acute and long-term cardiotoxicity risk of anthracyclines and increase in blood pressure with various cancer therapeutics remain to be elucidated. In this review, we cover the latest clinical data regarding the risk of hypertension across a spectrum of novel anticancer therapies as well as the underlying known or postulated pathophysiological mechanisms. Furthermore, we review the acute and long-term implications for the amplification of the development of cardiotoxicity with drugs not commonly associated with hypertension such as anthracyclines. An outline of management strategies, including pharmacological and lifestyle interventions as well as models of care aimed to facilitate early detection and more timely management of hypertension in patients with cancer and survivors concludes this review, which overall aims to improve both cardiovascular and cancer-specific outcomes.

An immune indicator based on BTK and DPEP2 identifies hot and cold tumors and clinical treatment outcomes in lung adenocarcinoma

In lung adenocarcinoma (LUAD), immune heterogeneity of hot and cold tumors has been recognized as one of the major factors affecting immunotherapy and other common treatments. However, there is still a lack of biomarkers that can effectively identify the immunophenotype of cold and hot tumors. First, the immune signatures were obtained based on literature mining, including macrophage/monocyte, IFN-γ response, TGF-β response, IL12 response, lymphocyte activation, and ECM/Dve/immune response. Subsequently, LUAD patients were further clustered into different immune phenotypes based on these immune signatures. Next, the key genes related to the immune phenotypes were screened by WGCNA analysis, univariate analysis, and lasso-cox analysis, and the risk signature was established via the key genes. In additional, we compared the clinicopathological characteristics, drug sensitivity, the abundance of immune infiltration, and the efficacy of immunotherapy and commonly used therapies between patients in the high- and low-risk groups in LUAD. LUAD patients were divided into immune hot phenotype and immune cold phenotype groups. The clinical presentation showed that patients with the immune hot phenotype had higher immunoactivity (including higher MHC, CYT, immune, stromal, ESTIMATE scores, higher abundance of immune cell infiltration, higher abundance of TIL, and enrichment of immune-enriched subtypes) and better survival outcomes than those with the immune cold phenotype. Subsequently, WGCNA analysis, univariate analysis, and lasso-cox analysis identified the genes highly associated with the immune phenotype: BTK and DPEP2. The risk signature, consisting of BTK and DPEP2, is highly correlated with the immune phenotype. High-risk scores were enriched in patients with immune cold phenotype and low-risk scores were enriched in patients with immune hot phenotype. Compared to the high-risk group, the low-risk group had better clinical performance, higher drug sensitivity, and a higher degree of immunoactivity, as well as better efficacy in receiving immunotherapy and common adjuvant therapy. This study developed an immune indicator consisting of BTK and DPEP2 based on the heterogeneity of hot and cold Immunophenotypes of the tumor microenvironment. This indicator has good efficacy in predicting prognosis and assessing the efficacy of immunotherapy, chemotherapy, and radiotherapy. It has the potential to facilitate personalized and precise treatment of LUAD in the future.

Structural Complementarity of Bruton’s Tyrosine Kinase and Its Inhibitors for Implication in B-Cell Malignancies and Autoimmune Diseases

Bruton’s tyrosine kinase (BTK) is a critical component in B-cell receptor (BCR) signaling and is also expressed in haematogenic and innate immune cells. Inhibition of BTK hyperactivity is implicated in B-cell malignancies and autoimmune diseases. This review derives the structural complementarity of the BTK-kinase domain and its inhibitors from recent three-dimensional structures of inhibitor-bound BTK in the protein data bank (PDB). Additionally, this review analyzes BTK-mediated effector responses of B-cell development and antibody production. Covalent inhibitors contain an α, β-unsaturated carbonyl moiety that forms a covalent bond with Cys481, stabilizing αC-helix in inactive-out conformation which inhibits Tyr551 autophosphorylation. Asn484, located two carbons far from Cys481, influences the stability of the BTK-transition complex. Non-covalent inhibitors engage the BTK-kinase domain through an induced-fit mechanism independent of Cys481 interaction and bind to Tyr551 in the activation kink resulting in H3 cleft, determining BTK selectivity. Covalent and non-covalent binding to the kinase domain of BTK shall induce conformational changes in other domains; therefore, investigating the whole-length BTK conformation is necessary to comprehend BTK’s autophosphorylation inhibition. Knowledge about the structural complementarity of BTK and its inhibitors supports the optimization of existing drugs and the discovery of drugs for implication in B-cell malignancies and autoimmune diseases.

Bruton's Tyrosine Kinase Inhibitors (BTKIs): Review of Preclinical Studies and Evaluation of Clinical Trials

In the last few decades, there has been a growing interest in Bruton's tyrosine kinase (BTK) and the compounds that target it. BTK is a downstream mediator of the B-cell receptor (BCR) signaling pathway and affects B-cell proliferation and differentiation. Evidence demonstrating the expression of BTK on the majority of hematological cells has led to the hypothesis that BTK inhibitors (BTKIs) such as ibrutinib can be an effective treatment for leukemias and lymphomas. However, a growing body of experimental and clinical data has demonstrated the significance of BTK, not just in B-cell malignancies, but also in solid tumors, such as breast, ovarian, colorectal, and prostate cancers. In addition, enhanced BTK activity is correlated with autoimmune disease. This gave rise to the hypothesis that BTK inhibitors can be beneficial in the therapy of rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), multiple sclerosis (MS), Sjögren's syndrome (SS), allergies, and asthma. In this review article, we summarize the most recent findings regarding this kinase as well as the most advanced BTK inhibitors that have been developed to date and their clinical applications mainly in cancer and chronic inflammatory disease patients.

B-Cell depletion therapy in IgG4-related disease: State of the art and future perspectives

IgG4-related disease (IgG4-RD) is an increasingly recognized immune-mediated fibroinflammatory disorder that promptly responds to glucocorticoids but commonly relapses during steroid tapering or after discontinuation. In the last few years, B-cell depletion therapy with rituximab (RTX) proved to be effective in the induction of remission and maintenance treatment of IgG4-RD, providing a new powerful tool in the management of this emerging condition. In this review, we outline the pathogenetic rationale for using B-cell depleting agents in IgG4-RD, we summarize available clinical experience with RTX in this disease, and we describe future possible therapies targeting B-lymphocytes that are now in the pipeline.

Recent Advances in Small Molecule Inhibitors for the Treatment of Osteoarthritis

Osteoarthritis refers to a degenerative disease with joint pain as the main symptom, and it is caused by various factors, including fibrosis, chapping, ulcers, and loss of articular cartilage. Traditional treatments can only delay the progression of osteoarthritis, and patients may need joint replacement eventually. As a class of organic compound molecules weighing less than 1000 daltons, small molecule inhibitors can target proteins as the main components of most drugs clinically. Small molecule inhibitors for osteoarthritis are under constant research. In this regard, by reviewing relevant manuscripts, small molecule inhibitors targeting MMPs, ADAMTS, IL-1, TNF, WNT, NF-κB, and other proteins were reviewed. We summarized these small molecule inhibitors with different targets and discussed disease-modifying osteoarthritis drugs based on them. These small molecule inhibitors have good inhibitory effects on osteoarthritis, and this review will provide a reference for the treatment of osteoarthritis.

Quantification of orelabrutinib in human plasma and cerebrospinal fluid by liquid chromatography tandem mass spectrometry

A sensitive and simple method was developed to determine orelabrutinib in human plasma and cerebrospinal fluid by liquid chromatography tandem mass spectrometry (LC-MS/MS). The samples were prepared by simple protein precipitation with by 0.1% formic acid acetonitrile solution and efficient separations were performed on the Thermo Hypersll GOLD C18 column (2.1 mm × 150 mm, 5 μm) under a gradient program in a total run time of 9 min. The orelabrutinib was detected by electrospray ionization in positive ion mode with selective reaction monitoring (SRM) and mass spectrometric conditions were optimized in order to increase selectivity and sensitivity. The developed method was validated in terms of its accuracy, precision, selectivity, linearity, recovery, matrix effect, stability, and limits of quantification (LOQ). The lower limit of quantification is 0.50 ng/mL, the intraday and interday precision RSD are both less than 15%, and the recovery rate is 85.7%-92.9%. Finally, the method was successfully applied for the quantitation of orelabrutinib in human plasma and cerebrospinal fluid of clinical patients treated with orelabrutinib.

Management of indolent B-cell Lymphomas: A review of approved and emerging targeted therapies

The indolent B-cell non-Hodgkin lymphomas (B-NHL) comprise a heterogenous group of lymphoproliferative disorders characterized by slow growth kinetics and a relapsing/remitting course. Management has, until recently, been uniform across all indolent B-NHL subtypes. Improving insight into pathophysiological and molecular features of each disease has led to development of several targeted therapies. Consequently, each subtype must now be considered an individual entity. In this review, we consider the three commonest indolent B-NHLs: follicular lymphoma, marginal zone lymphoma and Waldenstrom's macroglobulinemia and review in detail the data on approved and emerging targeted therapeutic agents for each B-NHL subtype.

Discovery of structural diverse reversible BTK inhibitors utilized to develop a novel in vivo CD69 and CD86 PK/PD mouse model

For the past two decades, BTK a tyrosine kinase and member of the Tec family has been a drug target of significant interest due to its potential to selectively treat various B cell-mediated diseases such as CLL, MCL, RA, and MS. Owning to the challenges encountered in identifying drug candidates exhibiting the potency block B cell activation via BTK inhibition, the pharmaceutical industry has relied on the use of covalent/irreversible inhibitors to address this unmet medical need. Herein, we describe a medicinal chemistry campaign to identify structurally diverse reversible BTK inhibitors originating from HITS identified using a fragment base screen. The leads were optimized to improve the potency and in vivo ADME properties resulting in a structurally distinct chemical series used to develop and validate a novel in vivo CD69 and CD86 PD assay in rodents.

Precision Medicine in Therapy of Non-solid Cancer

The development and approval of the tyrosine kinase inhibitor imatinib in 2001 has heralded the advance of directed therapy options. Today, an armamentarium of targeted therapeutics is available and enables the use of precision medicine in non-solid cancer. Precision medicine is guided by the detection of tumor-specific and targetable characteristics. These include pathogenic fusions and/or mutations, dependency on specific signaling pathways, and the expression of certain cell surface markers. Within the first part, we review approved targeted therapies for the compound classes of small molecule inhibitors, antibody-based therapies and cellular therapies. Particular consideration is given to the underlying pathobiology and the respective mechanism of action. The second part emphasizes on how biomarkers, whether they are of diagnostic, prognostic, or predictive relevance, are indispensable tools to guide therapy choice and management in precision medicine. Finally, the examples of acute myeloid leukemia, chronic lymphocytic leukemia, and chronic myeloid leukemia illustrate how integration of these biomarkers helps to tailor therapy.

Managing Waldenström's macroglobulinemia with BTK inhibitors

Bruton's tyrosine kinase (BTK) inhibition is one of the treatment standards for patients with relapsed/refractory Waldenström's macroglobulinemia (WM) and for patients with WM who are unsuitable for immunochemotherapy (ICT). It offers deep and durable responses with a manageable safety profile that is generally favorable compared with ICT regimens. However, the limitations of the first approved BTK inhibitor (BTKi), ibrutinib, include reduced efficacy in patients lacking the characteristic WM mutation (MYD88^L265P) and toxicities related to off-target activity. The risk of atrial fibrillation (AF) and other cardiovascular side effects are a notable feature of ibrutinib therapy. Several next-generation covalent BTKis with greater selectivity for BTK are at various stages of development. In November 2021, zanubrutinib became the first of these agents to be approved by the European Medicines Agency for the treatment of WM. Head-to-head trial data indicate that it has comparable efficacy to ibrutinib for patients with WM overall, although it may be more effective in patients with CXCR4 mutations or wild-type MYD88. In the clinical trial setting, its greater selectivity translates into a reduced risk of cardiovascular side effects, including AF. Acalabrutinib, which is pre-approval in WM, appears to offer similar advantages over ibrutinib in terms of its safety profile. Beyond the next-generation covalent BTKis, non-covalent BTKis are an emerging class with the potential to provide a therapeutic option for patients who relapse on covalent BTKis. In the future, BTKis may be increasingly utilized within combination regimens. Several ongoing trials in WM are investigating the potential for BTKi use in combination with established and novel targeted agents.

Targeting cereblon in hematologic malignancies

The protein cereblon (CRBN) is a substrate receptor of the cullin 4-really interesting new gene (RING) E3 ubiquitin ligase complex CRL4^CRBN. Targeting CRBN mediates selective protein ubiquitination and subsequent degradation via the proteasome. This review describes novel thalidomide analogs, immunomodulatory drugs, also known as CRBN E3 ubiquitin ligase modulators or molecular glues (avadomide, iberdomide, CC-885, CC-90009, BTX-1188, CC-92480, CC-99282, CFT7455, and CC-91633), and CRBN-based proteolysis targeting chimeras (PROTACs) with increased efficacy and potent activity for application in hematologic malignancies. Both types of CRBN-binding drugs, molecular glues, and PROTACs stimulate the interaction between CRBN and its neosubstrates, recruiting target disease-promoting proteins and the E3 ubiquitin ligase CRL4^CRBN. Proteins that are traditionally difficult to target (transcription factors and oncoproteins) can be polyubiquitinated and degraded in this way. The competition of CRBN neosubstrates with endogenous CRBN-interacting proteins and the pharmacology and rational combination therapies of and mechanisms of resistance to CRL4^CRBN modulators or CRBN-based PROTACs are described.

ASK120067 potently suppresses B-cell or T-cell malignancies in vitro and in vivo by inhibiting BTK and ITK

Hyperactivation of Bruton's tyrosine kinase (BTK) or interleukin-2-inducible T cell kinase (ITK) has been attributed to the pathogenesis of B-cell lymphoma or T-cell leukemia, respectively, which suggests that Bruton's tyrosine kinase and interleukin-2-inducible T cell kinase are critical targets for the treatment of hematological malignancies. We identified a novel third-generation epidermal growth factor receptor (EGFR) inhibitor, ASK120067 (limertinib) in our previous research, which has been applied as a new drug application against non-small cell lung cancer in China. In this work, we found that ASK120067 displayed potent in vitro inhibitory efficacy against Bruton's tyrosine kinase protein and interleukin-2-inducible T cell kinase protein via covalent binding. In cell-based assays, ASK120067 dose-dependently suppressed Bruton's tyrosine kinase phosphorylation and exhibited anti-proliferation potency by inducing apoptosis in numerous B-lymphoma cells. Meanwhile, it caused growth arrest and induced the apoptosis of T-cell leukemia cells by attenuating interleukin-2-inducible T cell kinase activation. Oral administration of ASK120067 led to significant tumor regression in B-cell lymphoma and T-cell leukemia xenograft models by weakening Bruton's tyrosine kinase and interleukin-2-inducible T cell kinase signaling, respectively. Taken together, our studies demonstrated that ASK120067 exerted preclinical anti-tumor activities against B-/T-cell malignancy by targeting BTK/ITK.