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Zanubrutinib is an orally administered second-generation covalent inhibitor of Bruton tyrosine kinase that was recently approved by the US Food and Drug Administration for the treatment of chronic lymphocytic leukemia and small lymphocytic leukemia. It has been associated with significant major and minor bleeding events, including intracranial and GI hemorrhage and hematuria, with or without concurrent antiplatelet or anticoagulation therapy. We report a case of a 65-year-old man with relapsing chronic lymphocytic leukemia. He presented to us with repeated episodes of worsening dyspnea secondary to hemorrhagic pleural effusion 2 months after the initiation of zanubrutinib with concomitant apixaban use. On discontinuation of zanubrutinib after the second episode, he remained asymptomatic on further follow-up examination. Previously only described with the first-generation Bruton tyrosine kinase inhibitor, our case focuses attention on a rare adverse event and a first reported incidence, to our knowledge, of recurrent hemorrhagic pleural effusion associated with zanubrutinib in a patient with relapsing chronic lymphocytic leukemia. [ABSTRACT FROM AUTHOR]

Summary Idiopathic multicentric Castleman disease (iMCD) is a rare and heterogeneous lymphoproliferative disorder that lacks standardised treatment options for patients with refractory or relapsed (r/r) disease. Blocking Bruton's tyrosine kinase (BTK) has emerged as a promising therapeutic approach for iMCD without depleting B cells. This single‐centre, retrospective study enrolled 10 patients with r/r iMCD who were treated with orelabrutinib, a novel, next‐generation BTK inhibitor. The median age at orelabrutinib initiation was 48 (range: 31–58) years. The overall response rate was 70% (7/10 patients, 95% CI: 34.8–93.3), with 20% (n = 2) achieving complete response and 50% (n = 5) achieving partial response. The median time to response was 9.8 (range: 5.9–20.5) months. Patients in the non‐responder group also demonstrated a continuous improvement in haemoglobin (91–105 g/L) and albumin (32–38 g/L) levels at month 12 of treatment despite not fulfilling response criteria. No grade 3 or higher adverse events occurred during the median time to the next treatment of 29.0 (range: 15.0–36.2) months. No patient mortality was recorded during the median follow‐up duration of 32.8 (range: 15.0–36.9) months. In conclusion, orelabrutinib is a safe and effective regimen for r/r iMCD. [ABSTRACT FROM AUTHOR]

• The update covers the approval of time-limited ibrutinib–venetoclax in first line and new data on MRD-driven treatment. • It also covers the approval of the BTKi zanubrutinib in both treatment-naive and relapsed or refractory CLL. • Additional evidence on the time-limited combination of venetoclax plus an anti-CD20 antibody in the first line are included. • Options for later-line treatments based on the type of prior lines of treatment are also included. • Recommendations are based on available scientific data and the authors' collective expert opinion. [ABSTRACT FROM AUTHOR]

One of the most successful and highly developed drug targets in cancer is Bruton's tyrosine kinase (BTK). Remarkable basic and translational studies have led to the clinical approval of several generations of small-molecule BTK inhibitors. Recent discovery of kinase-deficient BTK inhibitor resistance mutations sheds light on still undiscovered roles of BTK in B cell receptor signaling. Noncovalent BTK inhibitors represent potential future frontline treatment options in chronic lymphocytic leukemia (CLL). New dual-binding BTK inhibitors and BTK degraders represent the future of BTK targeting. Successful development of BTK inhibitors in cancer has led to new applications in other conditions such as autoimmune disease. Bruton's tyrosine kinase (BTK) inhibitors have revolutionized the treatment landscape for B cell lymphomas such as chronic lymphocytic leukemia (CLL). The first-in-class BTK inhibitor ibrutinib has recently been succeeded by covalent BTK inhibitors that are safer but still face challenges of resistance mutations. The noncovalent BTK inhibitor pirtobrutinib was recently approved for relapsed and refractory CLL, and whether noncovalent BTK inhibitors will supplant covalent BTK inhibitors as upfront treatment options either alone or in combination will be determined. Meanwhile, newer BTK inhibitors and BTK degraders are vying for their place in the potential future landscape of B cell cancers as well as autoimmune diseases. This review will cover the latest progress in BTK inhibitor development and where the field is moving in light of these recent discoveries. [ABSTRACT FROM AUTHOR]

To explore the optimal treatment for young patients with untreated mantle cell lymphoma (MCL), we compared the efficacy and safety of R-CHOP/R-DHAP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone/rituximab, dexamethasone, cytarabine and cisplatin) and R-BAP (rituximab, bendamustine, cytarabine, and prednisone) plus BTK (Bruton's tyrosine kinase) inhibitors in newly diagnosed patients. Eighty-three young patients (≤ 65 years old) with newly diagnosed MCL admitted to the First Affiliated Hospital of Zhengzhou University from January 1, 2014, to June 1, 2023, using R-CHOP/R-DHAP or R-BAP plus BTK inhibitor were assessed in this study. The median age at presentation was 60 (42–65) years in 83 patients, including 64 males and 19 females; 59 were treated with R-CHOP/R-DHAP regimen chemotherapy, and 24 were treated with R-BAP in combination with the BTK inhibitor regimen. The median follow-up was 17 months (2–86 months) in 83 patients, and the median PFS (progression-free survival) time was not reached. The CRR (complete response rate) of the R-BAP group was higher than that of the R-CHOP/R-DHAP group (87.5% vs. 54.2%, P = 0.005). The ORR (overall response rate) was not significantly different between the two groups (ORR: 91.7% vs. 84.7%, P = 0.497). The PFS (progression-free survival) of the R-BAP group was longer than that of the R-CHOP/R-DHAP group (P = 0.013), whereas OS was not significantly different between the two groups (P = 0.499). The most common adverse effect in both groups was hematotoxicity, with a higher incidence of grade 3–4 lymphopenia and grade 3–4 thrombocytopenia in the R-BAP group than in the R-CHOP/R-DHAP group (P = 0.015 and P = 0.039). Male sex (HR = 4.257, P = 0.013), LDH (lactate dehydrogenase) ≥ 245 U/L (HR = 3.221, P = 0.012), pleomorphic-blastoid (HR = 2.802, P = 0.043) and R-CHOP/R-DHAP regimen (HR = 7.704, P = 0.047) were independent risk factors for PFS. Ki67 ≥ 30% (HR = 8.539, P = 0.005) was an independent risk factor for OS. First-line treatment with R-BAP in combination with BTK inhibitor improved CRR and prolonged PFS in young patients with mantle cell lymphoma and adverse events were tolerable. [ABSTRACT FROM AUTHOR]

Chronic lymphocytic leukemia (CLL) is a monoclonal B-cell lymphoproliferative disease with a high annual incidence in Western countries. As B-cell receptor (BCR) signaling and intrinsic apoptotic resistance play critical roles in the development and survival of CLL cells, therapeutic approaches targeting these pathways have been extensively investigated to tackle this incurable disease. Over the last decade, several Phase 3 trials have confirmed the superior efficacy of covalent Bruton tyrosine kinase inhibitors (cBTKis) and venetoclax, a selective B-cell lymphoma 2 (BCL2) inhibitor, over chemoimmunotherapy. This has been demonstrated in both the treatment-naïve and relapsed/refractory (RR) settings and includes patients with high-risk molecular features. However, these drugs are not curative, with patients continuing to relapse after treatment with both cBTKis and BCL2is, and the optimal treatment strategy for these patients has not been defined. Several novel agents with distinct mechanisms have recently been developed for CLL which have demonstrated efficacy in patients who have previously received cBTKis and BCL2i. In particular, novel BCR-signaling targeting agents have shown promising efficacy in early-phase clinical trials for RR-CLL. Furthermore, cancer immunotherapies such as bispecific antibodies and chimeric antigen receptor T-cells have also shown anti-tumor activity in patients with heavily pretreated RR-CLL. Personalised approaches with these novel agents and combination strategies based on the understanding of resistance mechanisms have the potential to overcome the clinical challenge of what to do next for a patient who has already had a cBTKi and venetoclax. [ABSTRACT FROM AUTHOR]

BTK inhibitors (BTKi) are highly effective in B-cell malignancies. Acalabrutinib and zanubrutinib have exhibited favorable safety profiles when compared with ibrutinib. We identified all published/ presented randomized trials comparing a second-generation BTKi with ibrutinib and reconstructed individual patient-level, censored time-to-event data for adverse events to evaluate the impact of second-generation BTKi on safety outcomes including atrial fibrillation/flutter [AF], hypertension, bleeding, diarrhea, and infection. 1386 pts from ELEVATE-RR (n=533), ALPINE (n=652), and ASPEN (n=201) trials were included in the analyses. Acalabrutinib or zanubrutinib were associated with significant reductions in cumulative event rates of AF (HR 0.28, 95% CI 0.18–0.42, p<0.001), bleeding (HR 0.65, 95% CI 0.52–0.81, p<0.001), diarrhea (HR 0.61, 95% CI 0.47–0.78, p<0.001), hypertension (HR 0.40, 95% CI 0.27–0.61, p<0.001), and infections (HR 0.83, 95% CI 0.70-0.98, p=0.032). In summary, zanubrutinib and acalabrutinib have a favorable safety profile among pts with r/r B-cell malignancies. These data support use of acalabrutinib or zanubrutinib as preferred BTK inhibitors for approved indications. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Introduction: Cytotoxic CD8+ T cell (CTL) exhaustion is a dysfunctional state of T cells triggered by persistent antigen stimulation, with the characteristics of increased inhibitory receptors, impaired cytokine production and a distinct transcriptional profile. Evidence from immune checkpoint blockade therapy supports that reversing T cell exhaustion is a promising strategy in cancer treatment. Ibrutinib, is a potent inhibitor of BTK, which has been approved for the treatment of chronic lymphocytic leukemia. Previous studies have reported improved function of T cells in ibrutinib long-term treated patients but the mechanism remains unclear. We investigated whether ibrutinib directly acts on CD8+ T cells and reinvigorates exhausted CTLs. Methods: We used an established in vitro CTL exhaustion system to examine whether ibrutinib can directly ameliorate T cell exhaustion. Changes in inhibitory receptors, transcription factors, cytokine production and killing capacity of ibrutinibtreated exhausted CTLs were detected by flow cytometry. RNA-seq was performed to study transcriptional changes in these cells. Btk deficient mice were used to confirm that the effect of ibrutinib was independent of BTK expression. Results: We found that ibrutinib reduced exhaustion-related features of CTLs in an in vitro CTL exhaustion system. These changes included decreased inhibitory receptor expression, enhanced cytokine production, and downregulation of the transcription factor TOX with upregulation of TCF1. RNA-seq further confirmed that ibrutinib directly reduced the exhaustion-related transcriptional profile of these cells. Importantly, using btk deficient mice we showed the effect of ibrutinib was independent of BTK expression, and therefore mediated by one of its other targets. Discussion: Our study demonstrates that ibrutinib directly ameliorates CTL exhaustion, and provides evidence for its synergistic use with cancer immunotherapy. [ABSTRACT FROM AUTHOR]

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Introduction: Bruton tyrosine kinase inhibitor (BTKi) has demonstrated substantial efficacy in treating B-cell lymphoproliferative diseases (BLPD). Nonetheless, the significant discontinuation rates due to toxicity or financial reasons cannot be overlooked. In China, empirical evidence on the usage of BTKi remains scarce. Methods: To address this, a retrospective cohort study was conducted focused on 673 Chinese patients with BLPD who underwent at least one month of BTKi therapy. Results: Median age at BTKi initiation was 60 years. The median duration on BTKi treatment of the whole cohort was 36.4 months. The median post-BTK survival was not reach. BTKi-based treatment was permanently discontinued in 288 (43.8%) patients during follow-up, mostly attributed to progressive disease. Within the first 6 months of BTKi treatment, 76 patients (26.3%) had early treatment discontinuation. Patients with early discontinuation had extreme worse outcome with a median post-discontinuation survival of only 6.9 months. On multivariate analysis, withdrawal BTKi by toxicity and withdrawal BTKi within 6 months retained to be independent predictors of post-BTK survival, after taking account of the response depth, lines of therapy and baseline cytogenetics including 17p deletion. The decision between BTKi monotherapy and combination therapy, along with the preference for first or secondgeneration BTKi, exerted no significant impact on survival. Discussions: These observations contribute valuable real-world insights into the utilization of BTKi in China. We concluded that BTKi is an effective and welltolerated treatment for long-term use in Chinese patient population. However, it is imperative to stress that a proportion of patients discontinue BTKi early, leading to suboptimal outcomes. This study underscores the importance of adherence to BTKi therapy for improved clinical outcomes in real-world patients. [ABSTRACT FROM AUTHOR]

Background: The treatment landscape for chronic lymphocytic leukemia (CLL) continues to undergo considerable evolution. Optimal selection of initial therapy from multiple effective options provides a major challenge for clinicians, who need to consider both disease and patient factors in conjunction with a view to sequencing available therapies in event of disease relapse. Review: We explore the most topical clinically relevant unresolved questions through discussion of important available pertinent literature and propose expert opinion based on these data. (1) Shrinking role of chemoimmunotherapy (CIT); while novel therapies are generally superior, we highlight the utility of FCR for IGHV-mutated CLL. (2) Choosing between inhibitors of Bruton's tyrosine kinase (BTKi); while efficacy between agents is likely similar there are important differences in toxicity profiles, including the incidence of cardiac arrhythmia and hypertension. (3) BTKi with or without anti-CD20 monoclonal antibodies (mAb); while obinutuzumab-acalabrutinib (AO) may confer superior progression-free survival to acalabrutinib (Acala), this is not true of rituximab (Ritux) to ibrutinib (Ib)—we highlight that potential for increased side effects should be carefully considered. (4) Continuous BTKi versus time-limited venetoclax-obinutuzumab (VenO); we propose that venetoclax (Ven)-based therapy is generally preferable to BTKi with exception of TP53 aberrant disease. (5) BTKi-Ven versus VenO as preferred time-limited therapy; we discuss comparable efficacies and the concerns about simultaneous 1L exposure to both BTKi and Ven drug classes. (6) Utility of triplet therapy (BTKi-Ven-antiCD20 mAb) versus VenO; similar rates of complete response are observed yet with greater potential for adverse events. (7) Optimal therapy for TP53 aberrant CLL; while limited data are available, there are likely effective novel therapy combinations for TP53 aberrant disease including BTKi, BTKi-Ven ± antiCD20 mAb. Conclusion: Frontline therapy for CLL should be selected based on efficacy considering the patient specific biologic profile of their disease and potential toxicities, considering patient comorbidities and preferences. With the present paradigm of sequencing effective agents, 1L combinations of novel therapies should be used with caution in view of potential adverse events and theoretical resistance mechanism concerns in the absence of compelling randomized data to support augmented efficacy. [ABSTRACT FROM AUTHOR]

Summary: Waldenström macroglobulinaemia (WM) is characterized by the presence of a MYD88L265P mutation. This mutation promotes growth and survival of malignant cells through Bruton tyrosine kinase (BTK) activation. Ibrutinib was the first BTK inhibitor approved for WM. Intolerance to ibrutinib frequently leads to dose reductions, though the impact of reducing ibrutinib dosing has not been systematically studied. We performed a retrospective study to determine the frequency and impact of reducing ibrutinib dosing in WM patients. With a median treatment time of 64 months, 96 (27%) of 353 WM patients required a dose reduction due to adverse events such as musculoskeletal symptoms, cardiac events, dermatologic symptoms, cytopenias, and gastrointestinal symptoms. The median time to initial dose reduction was 9.3 months (range, 0.5–74). Dose reductions were more common in those 65 years of age or older versus under 65 [hazard ratio (HR) 2.46, 95% confidence interval (CI) 1.55–3.90; p < 0.001], and in females versus males (HR 2.20, 95% CI 1.41–3.28, p < 0.001). Most patients (65%) had improvement or resolution of adverse effects after initial dose reduction. With a median follow‐up of three years from dose reduction, hematologic response sustained or deepened in 79% of patients. These data suggest that dose reduction of ibrutinib is a reasonable treatment approach for patients with intolerable side effects. [ABSTRACT FROM AUTHOR]

Waldenström macroglobulinemia (WM) is a rare, non-Hodgkin lymphoma that remains incurable. Rituximab, an anti-CD20 monoclonal antibody has been the cornerstone of treatment against WM, and its combination with an alkylator, bendamustine, achieves durable remission in treatment-naive patients with symptomatic WM. However, novel "druggable" targets that have been identified within the clonal lymphoplasmacytic cells in WM have resulted in a rapid development of targeted therapies in both the frontline and relapsed and refractory (R/R) settings. Several agents directed against the known targets have shown promising efficacy, with mostly manageable toxicities. The class of Bruton's tyrosine kinase (BTK) inhibitors has transformed the therapeutic landscape for patients with WM, given their convenient oral dosing and strong efficacy, with high rates of attainment of very good partial response (VGPR). The tolerability of the next-generation BTK inhibitors appears to be superior to that of the first-in-class agent, ibrutinib. Targeted therapies from other classes have also demonstrated efficacy in both single-agent and combination regimens. Inhibitors of proteasome BCL-2, mTOR and PI-3 kinase have demonstrated efficacy in WM. Emerging therapies under investigation will continue to further shape the management paradigm, especially in the R/R setting. These include bispecific antibodies, radiotherapeutic agents and chimeric antigen receptor T-cell (CART) cell therapies. This review outlines the current literature and future direction of targeted therapies in WM. [ABSTRACT FROM AUTHOR]

Mantle cell lymphoma (MCL) is a heterogenous disease that is one of the most challenging blood cancers due to its poor prognosis, high risk of relapse and drug resistance. Recent researches have brought significant changes in MCL patients outcomes and new clinical. Bruton's Tyrosine Kinase (BTK), a key kinase in the B-cell antigen receptor (BCR) signaling pathway, is a clinical research hot spot and plays a major role in the survival and spread of malignant B cells. The first generation of BTK inhibitors, led by ibrutinib, have shown promising results in targeted treatment. Meanwhile, several inhibitors have entered clinical studies and demonstrated outstanding therapeutic activity in clinical trials for MCL, indicating a good prospect for development. Despite these encouraging findings, the duration of response is limited, and resistance to BTK inhibitors develops in a portion of individuals. This review summarizes the pathogenesis of MCL and targeted BTK inhibitors and provides an overview of the mutations that can lead to resistance to BTK inhibitors. The purpose of this article is to review the literature describing these selective therapies and provides perspectives for their further development. [ABSTRACT FROM AUTHOR]

Aberrant activity of histone deacetylases (HDACs) is frequently detected in B‐cell lymphomas, which indicated the therapeutic implications of HDAC inhibitors for B‐cell malignancies. We have discovered that lymphoma cells treated with HDAC inhibitor presented with activation of Bruton tyrosine kinase (BTK) which played an important role in the development of B‐cell malignancies. Therefore, our study intended to explore whether the addition of ibrutinib (BTK inhibitor) to chidamide (HDAC inhibitor) could generate combined anti‐tumor effects in B‐cell lymphomas. Using cell viability assay, cell cycle and apoptosis kit, we demonstrated an evident synergistic action of ibrutinib and chidamide in inhibiting tumor cell proliferation and motility. Consistent with in vitro data, the synergistic anti‐tumor effects were also observed in multiple tumor‐bearing mice models. By performing RNA‐seq and flow cytometry of tumor tissue, the enhancement of anti‐tumor immunity was observed with the co‐treatment of chidamide and ibrutinib. Together, these mechanistic insights indicated that simultaneously targeting BTK and HDAC could be a promising clinical therapy for B‐cell lymphomas. [ABSTRACT FROM AUTHOR]

This work investigates the synergistic potential of the nanostructured lipid carrier (NLC) gel of Ibrutinib with Curcumin as a repurposing strategy to treat psoriasis. In the present work, various components such as liquid lipid, solid lipid, and surfactant were selected and optimized based on the solubility of each drug, size, and polydispersity index. The optimized NLC consists of Capryol PGMC as liquid lipid, Glyceryl Mono Stearate as solid lipid, and Pluronics-F-127 as a surfactant. The prepared NLCs have a particle size of 95.12 ± 3.39 nm with PDI of 0.285 ± 0.009, exhibiting high entrapment efficiency (86.04 ± 2.86% for IBR and 87.25 ± 2.14% for CUR) with spherical geometry. CI value of 0.283 suggests synergism. Carbopol 940 was used as a gelling agent and has shown improved flux compared to plain drug gel. Anti-psoriatic studies in BALB/c mice indicated negligible skin irritation and improved histopathological features of psoriasis. Moreover, a reduced amount of inflammatory markers (TNF-alpha, IL-6, IL-22, and IL-23), and psoriasis severity score was observed with prepared gel than the IMQ group. The study suggested integrated benefits of repurposing Ibrutinib with Curcumin as NLC topical gel and it could possibly reduce remission of Psoriasis like inflammation and merit additional investigation. [ABSTRACT FROM AUTHOR]

Current therapeutic strategies for central nervous system (CNS) relapse of diffuse large B-cell lymphoma (DLBCL) are extremely limited. Secondary central nervous system lymphoma (SCNSL) also shows a grave prognosis and high mortality. This report describes a young female patient with DLBCL and CNS relapse who received low-dose CD19-directed chimeric antigen receptor T (CAR-T) cell therapy followed with Bruton's tyrosine kinase inhibitor and programmed cell death protein 1 antibody after several lines of chemotherapy. However, limited reports on CAR-T cell therapy are applied for SCNSL, particularly those in combination with targeted agents. The current treatment combination for this case provides a new regimen for CNS relapse from DLBCL. [ABSTRACT FROM AUTHOR]

Despite recent improvements in multiple myeloma (MM) treatment, MM remains an incurable disease and most patients experience a relapse. The major reason for myeloma recurrence is the persistent stem cell-like population. It has been demonstrated that overexpression of Bruton's tyrosine kinase (BTK) in MM stem cell-like cells is correlated with drug resistance and poor prognosis. We have developed a novel small BTK inhibitor, KS151, which is unique compared to other BTK inhibitors. Unlike ibrutinib, and the other BTK inhibitors such as acalabrutinib, orelabrutinib, and zanubrutinib that covalently bind to the C481 residue in the BTK kinase domain, KS151 can inhibit BTK activities without binding to C481. This feature of KS151 is important because C481 becomes mutated in many patients and causes drug resistance. We demonstrated that KS151 inhibits in vitro BTK kinase activities and is more potent than ibrutinib. Furthermore, by performing a semi-quantitative, sandwich-based array for 71-tyrosine kinase phosphorylation, we found that KS151 specifically inhibits BTK. Our western blotting data showed that KS151 inhibits BTK signaling pathways and is effective against bortezomib-resistant cells as well as MM stem cell-like cells. Moreover, KS151 potentiates the apoptotic response of bortezomib, lenalidomide, and panobinostat in both MM and stem cell-like cells. Interestingly, KS151 inhibits stemness markers and is efficient in inhibiting Nanog and Gli1 stemness markers even when MM cells were co-cultured with bone marrow stromal cells (BMSCs). Overall, our results show that we have developed a novel BTK inhibitor effective against the stem cell-like population, and potentiates the response of chemotherapeutic agents. [ABSTRACT FROM AUTHOR]

Aims: Examine relationships between the systemic exposure of acalabrutinib, a highly selective, next‐generation Bruton tyrosine kinase inhibitor, and its active metabolite (ACP‐5862) vs. efficacy and safety responses in patients with B‐cell malignancies who received acalabrutinib as monotherapy or in combination with obinutuzumab. Methods: For exposure–efficacy analyses, patients with untreated chronic lymphocytic leukaemia were assessed for best overall response, progression‐free survival and tumour regression. For exposure–safety analyses, incidences of grade ≥2 adverse events (AEs), grade ≥3 AEs and grade ≥2 events of clinical interest were assessed in patients with B‐cell malignancies. Acalabrutinib and ACP‐5862 pharmacokinetic (PK) parameter estimates were obtained from population PK modelling. Exposure calculations were based on study dosing regimens. Total active moieties were calculated to account for contributions of ACP‐5862 to overall efficacy/safety. Results: A total of 573 patients were included (exposure–efficacy analyses, n = 274; exposure–safety analyses, n = 573). Most patients (93%) received acalabrutinib 100 mg twice daily. Median total active area under the concentration–time curve (AUC24h,ss) and total active maximal concentration at steady‐state (Cmax,ss) were similar for patients who received acalabrutinib as monotherapy or in combination with obinutuzumab, and for responders and nonresponders. No relationship was observed between AUC24h,ss/Cmax,ss and progression‐free survival or tumour regression. Acalabrutinib AUC24h,ss and Cmax,ss were generally comparable across groups regardless of AE incidence. Conclusion: No clinically meaningful correlations between acalabrutinib PK exposure and efficacy and safety outcomes were observed. These data support the fixed acalabrutinib dose of 100 mg twice daily in the treatment of patients with B‐cell malignancies. [ABSTRACT FROM AUTHOR]

Bruton's Tyrosine Kinase (BTK) is considered crucial in the activation and survival of both physiological and malignant B-cells. In recent years, ibrutinib, an oral BTK inhibitor, became a breakthrough therapy for hematological malignancies, such as chronic lymphocytic. However, ibrutinib's feasibility might not end there. Several other kinases with established involvement with solid malignancies (i.e., EGFR, HER2) have been found to be inhibited by this agent. Recent discoveries indicate that BTK is a potential anti-solid tumor therapy target. Consequently, ibrutinib, a BTK-inhibitor, has been studied as a therapeutic option in solid malignancies. While most preclinical studies indicate ibrutinib to be an effective therapeutic option in some specific indications, such as NSCLC and breast cancer, clinical trials contradict these observations. Nevertheless, while ibrutinib failed as a monotherapy, it might become an interesting part of a multidrug regime: not only has a synergism between ibrutinib and other compounds, such as trametinib or dactolisib, been observed in vitro, but this BTK inhibitor has also been established as a radio- and chemosensitizer. This review aims to describe the milestones in translating BTK inhibitors to solid tumors in order to understand the future potential of this agent better. [ABSTRACT FROM AUTHOR]

Zanubrutinib is a highly selective, potent, orally available, targeted covalent inhibitor (TCI) of Bruton's tyrosine kinase (BTK). This work investigated the in vitro drug metabolism and transport of zanubrutinib, and its potential for clinical drug–drug interactions (DDIs). Phenotyping studies indicated cytochrome P450 (CYP) 3A are the major CYP isoform responsible for zanubrutinib metabolism, which was confirmed by a clinical DDI study with itraconazole and rifampin. Zanubrutinib showed mild reversible inhibition with half maximal inhibitory concentration (IC50) of 4.03, 5.69, and 7.80 μM for CYP2C8, CYP2C9, and CYP2C19, respectively. Data in human hepatocytes disclosed induction potential for CYP3A4, CYP2B6, and CYP2C enzymes. Transport assays demonstrated that zanubrutinib is not a substrate of human breast cancer resistance protein (BCRP), organic anion transporting polypeptide (OATP)1B1/1B3, organic cation transporter (OCT)2, or organic anion transporter (OAT)1/3 but is a potential substrate of the efflux transporter P-glycoprotein (P-gp). Additionally, zanubrutinib is neither an inhibitor of P-gp at concentrations up to 10.0 μM nor an inhibitor of BCRP, OATP1B1, OATP1B3, OAT1, and OAT3 at concentrations up to 5.0 μM. The in vitro results with CYPs and transporters were correlated with the available clinical DDIs using basic models and mechanistic static models. Zanubrutinib is not likely to be involved in transporter-mediated DDIs. CYP3A inhibitors and inducers may impact systemic exposure of zanubrutinib. Dose adjustments may be warranted depending on the potency of CYP3A modulators. [ABSTRACT FROM AUTHOR]

Background/Aim: Using a rat model of collageninduced arthritis (CIA), we evaluated the therapeutic effects of HM71224 (BTKi), as well as the drug-drug interactions in combined therapy with methotrexate (MTX) based on both drugs’ pharmacological role in immune regulation and antiinflammation. Materials and Methods: Arthritis in rats was induced using type II collagen and incomplete Freund’s adjuvant. The therapeutic effects of HM71224 (alone or in combination with MTX) were evaluated by arthritis score, paw volume, body weight, and histopathological examination (H&E and Safranin-O staining). The drug-drug interactions between HM71224 and MTX were investigated by measuring plasma, liver enzyme and creatinine levels and blood cell counts. Results: HM71224 reduced the clinical signs of arthritis, paw volume, and body weight loss in CIA rats. ED50 and ED90 were 1.0 and 2.5 mg/kg, respectively. HM71224 combined with MTX decreased the arthritis score, bone erosion, synovitis, and cartilage degradation without apparent interaction. Conclusion: The combination of HM71224 and MTX improved the therapeutic effect with no drug-drug interactions in RA. [ABSTRACT FROM AUTHOR]

In B-chronic lymphocytic leukemia (B-CLL), the interaction between leukemic cells and the microenvironment promotes tumor cell survival. The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib is one of the first-in-class molecules for the treatment of B-CLL patients; however, the emerging mechanisms of resistance to ibrutinib call for new therapeutic strategies. The purpose of the current study was to investigate the ability of ibrutinib plus the MDM2-inhibitor nutlin-3 to counteract the tumor microenvironment protective effect. We observed that primary B-CLL cells cultivated in microenvironment mimicking conditions were protected from apoptosis by the upregulation of c-MYC and of p53. In the same setting, combined treatments with ibrutinib plus nutlin-3 led to significantly higher levels of apoptosis compared to the single treatments, counteracting the c-MYC up-regulation. Moreover, the combination induced high p53 levels and a significant dissipation of the mitochondrial membrane potential, together with BAX cleavage in the more active p18 form and phospho-BAD down-regulation, that are key components of the mitochondrial apoptotic pathway, enhancing the apoptosis level. Our findings propose a new therapeutic strategy to overcome the tumor microenvironment protection involved in B-CLL resistance to drugs, with possible clinical implications also for other hematologic and solid tumors for which ibrutinib is considered a therapeutic option. [ABSTRACT FROM AUTHOR]

Mantle cell lymphoma is an aggressive B-cell malignancy. Current frontline chemoimmunotherapies produce high response rates but relapse is inevitable. Furthermore, the elderly and those with comorbidities are precluded from standard regimens and stem cell transplant, leaving them with limited options. Targeted therapies, including Bruton tyrosine kinase inhibitors, are an effective treatment strategy in mantle cell lymphoma. Zanubrutinib is a potent next-generation Bruton tyrosine kinase inhibitor that has demonstrated complete and sustained Bruton tyrosine kinase occupancy, minimal off-target effects and favorable pharmacokinetic/pharmacodynamic properties. Described herein is an ongoing Phase III study comparing the efficacy and safety of zanubrutinib plus rituximab followed by zanubrutinib monotherapy versus bendamustine plus rituximab followed by observation in transplant-ineligible patients with previously untreated mantle cell lymphoma. Clinical Trial Registration: NCT04002297 (ClinicalTrials.gov). [ABSTRACT FROM AUTHOR]

Treatment standards for chronic lymphocytic leukemia (CLL) have been transformed with the advent of effective inhibitors of B-cell receptor signaling such as ibrutinib - a first-in-class inhibitor of BTK. Off-target kinase inhibitions by ibrutinib are thought to contribute to its adverse events. Zanubrutinib is a next-generation BTK inhibitor with minimal off-target effects, sustained BTK occupancy in peripheral blood mononuclear cells and lymph nodes from patients with B-cell malignancies and promising responses in patients with CLL. Described here is a head-to-head Phase III study comparing the efficacy and safety of zanubrutinib with those of ibrutinib in patients with CLL/small lymphocytic lymphoma in the relapsed/refractory setting. [ABSTRACT FROM AUTHOR]

Mantle cell lymphoma (MCL) is a heterogeneous subtype of non-Hodgkin lymphoma that has been historically associated with poor 5-year overall survival rates, especially for aggressive variants. Traditional cytotoxic chemotherapy had been a mainstay of therapy for relapsed/refractory (R/R) MCL for many years until the advent of molecularly targeted therapies and cell-based approaches. However, a significant concern is the lack of definitive consensus guidelines for management of R/R MCL. The managerial conundrum partly stems from the absence of head-to-head comparisons of novel therapies, with conclusions drawn from cross-trial comparisons. In this evidence-based review, we discuss the current therapeutic options for R/R MCL, including the most recent data from the BRUIN study that led to the approval of the first-in-class non-covalent reversible Bruton's tyrosine kinase (BTK) inhibitor pirtobrutinib in 2023, as well as the recent removal of ibrutinib from the market. We discuss outlooks for targeted therapy and tolerability considerations for novel agents, including unique considerations for the elderly population. We highlight emerging data that support the curative potential of chimeric antigen receptor-T (CAR-T) therapy from ZUMA-2, relative to other promising investigational agents in the pipeline, including glofitamab, epcoritamab, and zilovertamab vedotin. We summarize management recommendations based upon the most rigorous clinical evidence to date. • Targeted therapeutic options for relapsed mantle cell lymphoma are expanding. • Cell-based approaches and reversible BTK inhibitors are gaining traction. • Bispecific T cell engagers are under investigation with promising preliminary data. [ABSTRACT FROM AUTHOR]

Waldenström macroglobulinemia (WM), an incurable B-cell malignancy, is sensitive to Bruton tyrosine kinase (BTK) inhibition with ibrutinib, a first-generation BTK inhibitor. Off-target effects of ibrutinib against TEC- and EGFR-family kinases are implicated in some adverse events. Patients with CXCR4WHIM and MYD88L265P mutations or who are MYD88WT have less sensitivity to ibrutinib than those with MYD88L265P and CXCR4WT disease. Zanubrutinib, a next-generation BTK inhibitor with potent preclinical activity in WM and minimal off-target effects, showed sustained BTK occupancy in peripheral blood mononuclear cells from patients with B-cell malignancies and promising responses in advanced WM. Described here is a head-to-head Phase III study comparing efficacy and safety of zanubrutinib and ibrutinib in WM patients. Effect of MYD88 and CXCR4 mutation status will be assessed. [ABSTRACT FROM AUTHOR]

Bruton's tyrosine kinase (BTK) plays a crucial role in adaptive and immune responses by modulating B-cell, Fc, toll-like, and chemokine receptor signaling pathways. BTK inhibition is a promising therapeutic approach for the treatment of inflammatory and autoimmune diseases. The development of novel, highly selective, and less toxic BTK inhibitors may be beneficial for the treatment of autoimmune diseases with unmet medical needs. In this study, structure-based drug design was used to discover a series of novel, potent, and selective covalent BTK inhibitors with a 1,4,5,6,8-pentaazaacenaphthylen scaffold. Among them, compound 36R exhibited high kinase selectivity, long target occupancy time, appropriate pharmacokinetic properties, and dose-dependent efficacy in a rat model of collagen-induced arthritis. Therefore, 36R is a novel BTK inhibitor requiring further development for the treatment of autoimmune diseases. [Display omitted] • A series of novel, selective, and potent covalent BTK inhibitors were discovered. • 36R exhibited potent in vitro activity with high kinase selectivity. • 36R exhibited long target occupancy time and appropriate pharmacokinetic properties. • 36R exhibited dose-dependent efficacy in a rat model of collagen-induced arthritis. [ABSTRACT FROM AUTHOR]

Developing Bruton's tyrosine kinase (BTK) inhibitors has become a significant focus in recent years because BTK inhibition is an effective approach for the treatment of B-cell malignancies. For covalent BTK inhibitors, low oral bioavailability and low kinase selectivity remain unaddressed issues; thus, more diverse inhibitors with both novel structures and selective on target binding profiles are still needed. Here, four key regions where inhibitors bind to BTK were identified by analyzing the existing crystal structures of BTK complexes. Then, a scaffold-based molecular design work flow was established by integrating fragment-growing method, deep learning-based framework XGraphBoost and molecular docking, leading to four compounds that showed potency against BTK. Optimization of compounds 1 and 2 led to the discovery of the potent BTK inhibitor compound 42 by using in vitro potency and pharmacokinetic (PK) studies to prioritize the compounds. Compound 42 exhibited great BTK inhibition activity (IC 50 = 0.7 nM) along with high oral absorption. Moreover, 42 demonstrated excellent kinase selectivity, especially over EGFR kinase, and low toxicity. In a TMD8 xenograft model, 42 significantly inhibited tumor growth (TGI = 104%) at a dosage of 50 mg/kg, indicating its potential as a novel therapeutic option for B-cell lymphomas. [Display omitted] • A series of pyrrolopyrimidine-containing BTK inhibitors were synthesized. • 42 demonstrated excellent kinase selectivity and low toxicity. • 42 showed a significant in vivo antitumor activity. [ABSTRACT FROM AUTHOR]

The Bruton tyrosine kinase (BTK) inhibitor, zanubrutinib, was designed for high BTK specificity and minimal toxicity. SEQUOIA (NCT03336333) is a global, open-label, randomized phase 3 study in treatment-naive patients with CLL//SLL without del(17p) who were unsuitable for fludarabine//cyclophosphamide/rituximab. Patients were randomized to receive zanubrutinib (160 mg twice daily) or bendamustine (day 1-2: 90 mg/m²) and rituximab (cycle 1: 375 mg/m²; cycles 2-6: 500 mg/m²); stratification factors were age (<65 y vs. ≥65 y), Binet Stage, IGHV mutation, and geographic region. Primary endpoint was independent review committee (IRC)-assessed progression-free survival (PFS). Secondary endpoints included investigator-assessed (INV) PFS, overall response rate (ORR), overall survival (OS), and safety. From 31 Oct 2017-22 Jul 2019, 479 patients were enrolled (zanubrutinib = 241; BR = 238). Baseline characteristics (zanubrutinib vs. BR): median age, 70.0 y vs. 70.0 y; unmutated IGHV, 53.4% vs. 52.4%; del(11q), 17.8% vs. 19.3%. With median follow-up of 26.2 mo, PFS was significantly prolonged with zanubrutinib by IRC (HR 0.42; 2-sided p <0.0001), and INV (HR 0.42; 2-sided p = = 0.0001). Zanubrutinib treatment benefit occurred across age, Binet stage, bulky disease, del(11q) status and unmutated IGHV (HR 0.24; 2-sided p <0.0001), but not mutated IGHV (HR 0.67; 2-sided p = 0.1858). For zanubrutinib vs. BR, 24-mo PFS-IRC = 85.5% vs. 69.5%; ORR-IRC = 94.6% vs. 85.3%; complete response rate = 6.6% vs. 15.1%; ORR-INV = 97.5% vs. 88.7%; and 24-mo OS = 94.3% vs. 94.6%. Select adverse event (AE) rates (zanubrutinib vs. BR): atrial fibrillation (3.3% vs. 2.6%), bleeding (45.0% vs. 11.0%), hypertension (14.2% vs. 10.6%), infection (62.1% vs. 55.9%), and neutropenia (15.8% vs. 56.8%). Treatment discontinuation due to AEs (zanubrutinib vs. BR) = = 20 patients (8.3%) vs. 31 patients (13.7%); AEs leading to death = 11 patients (4.6%) vs. 11 patients (4.8%). No sudden deaths occurred. In summary, zanubrutinib significantly improved PFS-IRC vs. BR and was well tolerated, supporting the potential utility of frontline zanubrutinib in treatment-naive CLL/SLL. [ABSTRACT FROM AUTHOR]

The scope of dermatologic adverse events to ibrutinib has not been systematically described. We sought to determine the incidence and severity of ibrutinib-associated dermatologic toxicities and provide management recommendations. We conducted a systematic literature search of clinical trials and cohorts investigating ibrutinib monotherapy for cancer or chronic graft-versus-host disease through June 2020. Thirty-two studies with 2258 patients were included. The incidence of all-grade toxicities included cutaneous bleeds (24.8%; 95%CI, 18.6–31.0%), mucocutaneous infections (4.9%; 95%CI, 2.9–7.0%), rash (10.8%; 95%CI. 6.1–15.5%), mucositis (6%; 95%CI, 3.6–8.5%), edema (15.9%; 95%CI, 11.1–20.6%), pruritus (4.0%; 95%CI, 0.0–7.9%), xerosis (9.2%; 95%CI, 5.5–13.0%), nail changes (17.8%; 95%CI, 4.1–31.5%), and hair changes (7.9%; 95%CI, 0.0–21.3%). The incidence of high-grade toxicities included mucocutaneous infection (1.3%; 95%CI, 0.5–2.2%), rash (0.1%; 95%CI, 0.0–0.2%), mucositis (0.1%; 95%CI, 0.0–0.3%), and edema (0.1%; 95%CI, 0.0–0.2%). It is imperative that clinicians familiarize themselves with ibrutinib-associated dermatologic toxicities to learn how to manage them, prevent discontinuation, and improve patient outcomes. [Display omitted] • Ibrutinib-associated dermatologic toxicities are common • Toxicities included cutaneous bleeds, mucocutaneous infections, and nail changes • High-grade toxicities included mucocutaneous infections, rash, mucositis, and edema • Toxicity identification and management are needed to improve patient outcomes [ABSTRACT FROM AUTHOR]

Bruton's tyrosine kinase (BTK) and phosphoinositide 3-kinase (PI3K) in the B-cell receptor (BCR) signaling pathway are considered potential therapeutic targets for the treatment of B-cell lymphomas, among which, diffuse large B-cell lymphoma (DLBCL) is the most common type. Herein, we comparatively evaluated the single and combined application of the BTK inhibitor ibrutinib and the selective PI3Kγ inhibitor AS-605240 in the canine DLBCL cell line CLBL-1. For further comparison, key findings were additionally analyzed in canine B-cell leukemia GL-1 and human DLBCL cell line SU-DHL-4. While ibrutinib alone induced significant anti-proliferative effects on all cell lines in a dose-dependent manner, AS-605240 only induced anti-proliferative effects at high concentrations. Interestingly, ibrutinib and AS-605240 acted synergistically, reducing cell proliferation and increasing apoptosis/necrosis in all cell lines and inducing morphological changes in CLBL-1. Moreover, the combined application of ibrutinib and AS-605240 reduced relative phosphorylation and, in some instances, the levels of the BTK, AKT, GSK3β, and ERK proteins. Comparative variant analysis of RNA-seq data among canine B- and T-lymphoid cell lines and primary B-cell lymphoma samples revealed potentially high-impact somatic variants in the genes that encode PI3K, which may explain why AS-605240 does not singly inhibit the proliferation of cell lines. The combination of ibrutinib and AS-605240 represents a promising approach that warrants further in vivo evaluation in dogs, potentially bearing significant value for the treatment of human DLBCL. [ABSTRACT FROM AUTHOR]

[Display omitted] • 15c exhibited potent BTK inhibitory activity. • 15c inhibited BTK signaling in Z138 cells at low micromolar effectively. • 15c induced cell apoptosis in Z138 cells at low micromolar strongly. • 15c showed higher ROS levels in Z138 cells than ibrutinib. • 15c induced autophagy in Z138 cells. Ibrutinib, a potent irreversible Bruton's tyrosine kinase (BTK) inhibitor, was approved by the FDA for treating mantle cell lymphoma (MCL). Although ibrutinib exhibited excellent antitumor activity, it was associated with certain adverse reactions, with off-target effects against EGFR, Itk and Src family kinases. Our studies yielded a novel series of substituted benzyl pyrrolopyrimidine derivatives capable of potent inhibition of BTK. Compared with ibrutinib, compound 15c exhibited potent BTK inhibitory activity and enhanced antiproliferative activity, a 12–24-fold increase, against MCL cell lines, with IC 50 values lower than 1 μM. Low micromolar doses of 15c inhibited the BCR signaling pathway and strongly induced the apoptosis of Z138 cells. Ibrutinib and 15c induced autophagy in a dose-dependent manner in Z138 cells. Moreover, compound 15c induced the production of reactive oxygen species (ROS), which may be a reason for its potent antiproliferative activity. Importantly, compound 15c showed greater BTK selectivity than ibrutinib, indicating a potentially safer treatment of MCL. [ABSTRACT FROM AUTHOR]