Bruton's Tyrosine Kinase Inhibitor Research Articles

Real-world characteristics, treatment patterns, and outcomes of patients with 2 or more LOTs for CLL/SLL in the United States

AbstractThe development of targeted agents for chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) has transformed the treatment paradigm for patients with CLL. Because of this evolving treatment landscape, there was a need for contemporaneous evidence related to US treatment patterns and outcomes among patients treated in the real world. Using COTA’s electronic health records–based database, we examined characteristics, treatment patterns, and outcomes of patients receiving ≥2 line of therapy (LOT). A total of 1283 adult patients with CLL/SLL were identified in the data set who initiated second LOT (2L) between 1 January 2014 and 30 June 2022. Of those patients, 542 patients (42.2%) later received third-line (3L) therapy, of whom 228 (42.1%) went on to receive fourth-line (4L) therapy. Overall, >18% of patients died after 2L initiation and before 3L initiation, and more than a quarter died before 4L initiation. The majority of the population was White (77.7%), male (60.6%), aged ≥65 years (68.8%), and treated in a community practice setting (87.8%). Regarding treatment patterns, from 2014 to 2023, use of chemoimmunotherapy in any ≥2L LOT decreased, whereas use of Bruton tyrosine kinase inhibitor and B-cell lymphoma 2 inhibitor therapy increased. Across end points, median time to event(s) were generally shorter with each subsequent LOT received, both in the overall population and among patients receiving a given therapy in different LOTs. With a median follow-up time from 2L initiation of 38.0 months, median real-world time to next treatment, progression-free survival, and overall survival from 2L was 31.9, 33.8, and 80.1 months, respectively. Despite great advancements in CLL/SLL treatments since 2014, unmet need persists for patients receiving late LOT.

151 (PB139): CFON-026, a best-in-class macrocyclic non-covalent inhibitor of BTK (WT) and all clinically relevant BTK resistance mutations

151 (PB139): CFON-026, a best-in-class macrocyclic non-covalent inhibitor of BTK (WT) and all clinically relevant BTK resistance mutations

Expression analysis, molecular docking and molecular dynamics simulations to identify potential BTK inhibitors: strategy for targeting pan-cancer

ABSTRACT Bruton's Tyrosine Kinase (BTK), a soluble tyrosine kinase plays an essential role in the growth, development, and signalling of B cells. It is a non-receptor kinase that is crucial for leukemic cell survival, proliferation, and oncogenic signalling in many B cell malignancies. The enhanced metastasis caused by BTK expression may be reduced by BTK inhibitors, which also have powerful therapeutic effects. The goal of the study is to identify potential inhibitors which have good binding affinity with BTK. The current study also aims to investigate the expression pattern and the prognostic significance of BTK across all cancer types. Interestingly, it was found that BTK was highly overexpressed in numerous cancer types including; clear cell renal carcinoma, glioblastoma, head and neck, liver and breast cancer. BTK was found to reduce the relapse-free and overall survival rate. Furthermore, using in silico approach two structural analogues of Pirtobrutinib namely; 163207918 and 129269825 that bind to BTK with higher affinity were identified. Using drug-likeness analysis the therapeutic possibility of screened Pirtobrutinib analogues were evaluated. The Molecular docking and dynamic analysis revealed that the new Pirtobrutinib analogues could be potent inhibitors with higher binding affinity and stability in comparison with the parent compound. In conclusion, after preclinical and clinical research, the identified analogues may open the door for their prospective use in cancer therapy.

Profound deficiencies in mature blood and bone marrow progenitor dendritic cells in Chronic Lymphocyticcytic Leukemia patients.

Chronic lymphocytic leukemia (CLL) patients are immunocompromised and highly vulnerable to serious recurrent infections. Conventional dendritic cells (cDCs) and plasmacytoid DCs (pDCs) are principal sensors of infection and are essential in orchestrating innate and adaptive immune responses to resolve infection. This study identified significant deficiencies in six functionally distinct DC subsets in blood of untreated CLL (UT-CLL) patients and selective normalization of pDCs in response to acalabrutinib (a Bruton tyrosine kinase inhibitor) therapy. DCs are continuously replenished from hematopoiesis in bone marrow (BM). Four BM developmental intermediates that give rise to cDCs and pDCs were examined and significant reductions of these were identified in UT-CLL patients supporting a precursor/progeny relationship. The deficiencies in blood DCs and BM DC progenitors were significantly associated with alterations in the Flt3/FL signaling pathway critical to DC development and function. Regarding clinical parameter, cDC subset deficiencies are associated with adverse prognostic indicators of disease progression, including IGHV mutation, CD49d, CD38, and ZAP-70 status. Importantly, UT-CLL patients with shared DC subset deficiencies had shorter time-to-first treatment (TTFT), uncovering a profound alteration in innate immunity with the potential to instruct therapeutic decision-making.

Acalabrutinib in chronic lymphocytic leukemia therapy: literature review and experience of the Clinical and Diagnostic Center of the Lapino Clinical hospital

Chronic lymphocytic leukemia (CLL) is a B-cell tumor consisting of small lymphocytes. It develops through a multistage process of a series of genomic events. Bruton’s tyrosine kinase (BTK) plays an important role in signal transduction through constantly active BCR pathway. It participates in all aspects of B cell development including proliferation, maturation, differentiation, and apoptosis. Therefore, it seems reasonable to modulate BTK using pharmaceutical agents with the goal to suppress tumor process. The effect of 1st generation BTK inhibitor ibrutinib on non-target kinases is significant and causes some adverse events which can limit its use in older patients with concomitant pathologies. The results of completed trails have convincingly shown safety advantage and similar effectiveness of highly selective 2nd generation BTK inhibitor acalabrutinib compared to ibrutinib in all subgroups of patients with CLL. Considering the necessity of long term BTK inhibitor therapy (until progression or unacceptable progression), long-term manageable safety profile of acalabrutinib is important. The article discusses clinical pharmacology, effectiveness and safety of acalabrutinib therapy in the context of clinical trials. Analysis of medical histories of patients with CLL treated at the Clinical and Diagnostic Center of the Lapino Clinical Hospital, “Mother and Child” group of companies, in the last year was performed, and indications for treatment using 2nd generation BTK inhibitor were evaluated.

Ocular Surface Squamous Neoplasia In Situ Secondary to Bruton Tyrosine Kinase Inhibitor Therapy.

Bruton tyrosine kinase (BTK) inhibitors have become an important therapeutic option in treating B-cell malignancies including non-Hodgkin lymphoma and chronic lymphocytic leukemia. However, a noted morbidity associated with their use is the potential for the development of second primary malignancy related to immunomodulation. In this case, we report a second primary malignancy of ocular surface squamous neoplasia (OSSN) owing to BTK therapy. The OSSN was successfully treated and has been monitored without recurrence. To our knowledge, this is the first case of OSSN secondary to BTK therapy.

Phase IB part of LOC-R01, a LOC network non-comparative randomized phase IB/II study testing R-MPV in combination with escalating doses of lenalidomide or ibrutinib for newly diagnosed primary central nervous system lymphoma (PCNSL) patients

BackgroundResults of conventional induction chemotherapies in primary central nervous system lymphoma (PCNSL) need to be improved. Ibrutinib, a BTK inhibitor, and lenalidomide, an immunomodulatory drug, have shown promising results at relapse, supporting to further assess their individual use in combination with high-dose methotrexate-based chemotherapy.MethodsPatients with newly diagnosed PCNSL were randomized to receive four 28-day cycles of ibrutinib or lenalidomide in combination with R-MPV (rituximab, methotrexate, procarbazine, vincristine and prednisone) in a 3 + 3 design. Responders then received a consolidation with R-Cytarabine and an intensive chemotherapy with autologous stem cell transplantation. The objective of the phase IB study was to define the recommended phase II dose (RP2D) based on the dose-limiting toxicity (DLT) occurring during the first induction cycle.ResultsTwenty-six patients (median age 52) were randomized. Four DLTs were observed: one grade 5 aspergillosis and pneumocystosis, one grade 4 catheter-related infection and two grade 3 increased alanine aminotransferase levels. RP2D of ibrutinib and lenalidomide were 560 mg daily (D3-14 and D17-28) and 15 mg daily (D1-21) respectively, in combination with R-MPV. In both arms, the most frequent grade ≥3 treatment-related adverse events were hepatic cytolysis, neutropenia and infections. One grade 4 Lyell’s syndrome was reported at cycle 2 in the lenalidomide arm. After 4 induction cycles, the overall response rates were 76.9% and 83.3% in the lenalidomide and ibrutinib arm, respectively.ConclusionTargeted induction therapies combining lenalidomide or ibrutinib with R-MPV are feasible for first-line PCNSL. The safety profile is consistent with the known safety profiles of R-MPV and both targeted therapies. The phase II part of the study is ongoing.Trial registrationNCT04446962.

The Economic Impact of Treatment Sequencing in Chronic Lymphocytic Leukemia in Canada Using Venetoclax plus Obinutuzumab.

Bruton tyrosine kinase inhibitors (BTKis) represent an advancement in chronic lymphocytic leukemia; however, these agents are administered continuously until disease progression or unacceptable toxicity, raising concerns about their affordability. Venetoclax in combination with obinutuzumab (VO) is a fixed-duration (12-month) treatment, approved in Canada in 2020. This study estimated the total cumulative cost of different treatment sequences and evaluated the economic impact of introducing treatment sequences with/without VO, from a Canadian health care system perspective. A 10-year partitioned survival model was developed, considering key clinical parameters and direct medical costs. Results were stratified by TP53 aberration. Treatment sequences starting with first-line (1L) VO resulted in lower 10-year cumulative costs compared to sequences starting with BTKis administered until disease progression, across both TP53 aberration subgroups. With a maximum of three lines of treatment over a 10-year period, cumulative costs were largely determined by the first two lines of treatment. When comparing sequences with the same 1L treatment, sequences with BTKis in second-line incurred greater costs compared to fixed-duration regimens. Overall, the economic impact of treating all patients with VO led to 10-year cumulative savings of CAD 169,341 and CAD 293,731 per patient, without and with TP53 aberration, respectively. These savings are mainly due to reductions in treatment costs associated with fixed treatment duration.

Clinicopathological and genetic analysis of interstitial disease-like pulmonary intravascular large B cell lymphoma

Objective: To investigate the clinicopathological features and genetic mutation status of pulmonary intravascular large B cell lymphoma. Methods: The clinicopathological data of eight patients diagnosed with pulmonary intravascular large B cell lymphoma, from April 2018 to May 2023, were retrospectively analyzed. The genetic profile of six patients was detected via next-generation sequencing (NGS) and followed up. Results: All patients included one male and seven females, with a median age of 64 years (ranging from 45 to 66 years). Respiratory symptoms were the most common (7 cases), B symptoms in two cases, hemophagocytic syndrome in two cases. Multiple diffuse ground-glass opacities in both lungs were observed based on the high-resolution chest CT scan. Six cases of mild to moderate ventilation or diffusion dysfunction were observed based on the pulmonary function tests. Moreover, two cases of hypoxemia and two cases with type Ⅰ respiratory failure were recorded. The serum lactate dehydrogenase level increased (7/8), β2-MG level increased (2/8), neuron-specific enolase level increased (7/8), total number of peripheral blood lymphocytes decreased (7/8), and clinical stages were all stage Ⅳ. The neoplastic lymphoid cells were lodged in the lumina of venules and capillaries of the alveolar septum; the tumor cells were large, with prominent nucleoli and frequent mitotic figures. The malignant cells were detected in the extravascular surrounding lung tissue in all cases. The tumor cells expressed mature B cell-associated antigens CD20 and CD79a, and the vascular endothelial markers CD31 and CD34 showed that the tumor cells were filled in the blood vessels, infiltrated blood vessel walls, and perivascular areas. One case was germinal center-type, seven cases were non-germinal center-type, two cases were double-expressing lymphoma, and all cases were EBER-negative. Furthermore, the top five genes with mutation frequencies detected by NGS were MYD88 (5/6), PIM1 (5/6), CD79B (4/6), TCF3 (4/6), and TP53 (3/6). Of the eight cases, seven patients received R-CHOP-based chemotherapy, six cases had complete remission after chemotherapy, one case died, and one case was lost to follow-up. Conclusions: Pulmonary vascular large B cell lymphoma is rare, which shares similar patterns with interstitial lung disease on imaging. Transbronchial lung biopsy is an effective method to confirm the diagnosis. Immunochemotherapy with BTK inhibitors can provide a survival advantage for patients in the future based on molecular typing.

Acalabrutinib in Chinese patients with relapsed/refractory chronic lymphocytic leukemia: Primary analysis from an open-label, multicenter phase 1/2 trial.

Acalabrutinib is a highly selective Bruton tyrosine kinase inhibitor approved in the United States and Europe for chronic lymphocytic leukemia (CLL) based on phase 3 trials with limited representation of Asian populations. This phase 1/2 trial evaluates acalabrutinib in Chinese adults with relapsed/refractory (R/R) CLL receiving acalabrutinib 100mg twice daily in 28-day cycles until disease progression or treatment discontinuation due to adverse events (AEs) presenting substantial clinical risk. The primary endpoint was blinded independent central review (BICR)-assessed overall response rate (ORR). A total of 60 patients from 20 sites in China received acalabrutinib (median age 62years; median 1 prior therapy line; 21.7% with del(17p) and/or TP53 mutation; 51.7% with unmutated IGHV). Median total treatment duration was 19.4months (range 0.6-28.2) with 53 patients (88.3%) receiving acalabrutinib at data cutoff; median study follow-up was 20.2months. BICR-assessed ORR was 85.0% (95% CI, 73.4-92.9). Median duration of response, progression-free survival (PFS), and overall survival (OS) were not reached. Estimated 12-month and 18-month PFS rates were 91.5% (95% CI, 80.9-96.4) and 78.8% (95% CI, 60.9-89.2); OS rates were both 96.7% (95% CI, 87.3-99.2). AEs of grade ≥ 3 occurred in 25 patients (41.7%), most commonly decreased neutrophil count (13.3%, n = 8), pneumonia (6.7%, n = 4), and upper respiratory tract infection (6.7%, n = 4). AEs led to treatment discontinuation in 2 patients (paraneoplastic pemphigus; rectal neoplasm). This study demonstrated high ORR in acalabrutinib-treated Chinese patients with R/R CLL with no unexpected safety concerns. This trial is registered on ClinicalTrials.gov (NCT03932331).

A Phase II Study Assessing Long-term Response to Ibrutinib Monotherapy in Recurrent or Refractory CNS Lymphoma.

Ibrutinib is a first-in-class inhibitor of Bruton tyrosine kinase. We previously reported the safety and short-term antitumor activity of ibrutinib in 20 patients with relapsed or refractory (r/r) primary central nervous system (CNS) lymphoma (PCNSL) or secondary CNS lymphoma (SCNSL). We enrolled 26 additional patients with r/r PCNSL/SCNSL into the dose-expansion cohort of the trial into a combined cohort of 46 patients (31 with PCNSL and 15 with SCNSL). Patients received ibrutinib at 560 or 840 mg daily in the dose-escalation cohort and ibrutinib at 840 mg daily in the expansion cohort. The median follow-up was 49.9 and 62.1 months for patients with PCNSL and SCNSL, respectively. We sequenced DNA from available tumor biopsies and cerebrospinal fluid collected before and during ibrutinib therapy. Tumor responses were observed in 23/31 (74%) patients with PCNSL and 9/15 (60%) patients with SCNSL, including 12 complete responses in PCNSL and 7 in SCNSL. The median progression-free survival (PFS) for PCNSL was 4.5 months [95% confidence interval (CI), 2.8-9.2] with 1-year PFS at 23.7% (95% CI, 12.4%-45.1%). The median duration of response in the 23 PCNSL responders was 5.5 months. The median PFS in SCNSL was 5.3 months (95% CI, 1.3-14.5) with a median duration of response of 8.7 months for the 9 responders. Exploratory biomarker analysis suggests that mutations in TBL1XR1 may be associated with a long-term response to ibrutinib in PCNSL (P = 0.0075). Clearance of ctDNA from cerebrospinal fluid was associated with complete and long-term ibrutinib responses. Our study confirms single-agent activity of ibrutinib in r/r CNS lymphoma and identifies molecular determinants of response based on long-term follow-up.

Discovery of new non-covalent reversible BTK inhibitors: Synthesis, in silico studies, and in vitro evaluations

Bruton's Tyrosine Kinase (BTK) played a key role in the B cell antigen receptor (BCR) signaling pathway, and was considered a hotspot in the treatment of B cell malignant tumors and B cell immune diseases. There were 5 covalent irreversible inhibitors launched currently on the market, but C481S mutation was detected in most patients after administration. The approval of Pirtobrutinib (Jaypirca) by FDA in 2023 aroused great interest in the development of non-covalent and reversible BTK inhibitors. In order to solve the resistance of covalent irreversible inhibitors caused by C481S mutation, 11 reversible BTK inhibitors were designed based on screening in this article. The design, synthesis, in silico studies, and in vitro evaluations were performed for further verification. Among them, compound WS-11 showed best activity with IC50 of 3.9 nM for wild type, 2.2 nM for C481S mutation BTK, which was comparable to the positive control Pirtobrutinib. Furthermore, WS-11 would have a good druglikeness properties predicted by pkCSM and SwissADME, which provided a promising lead for further optimization and development.

A Bruton tyrosine kinase inhibitor-resistance gene signature predicts prognosis and identifies TRIP13 as a potential therapeutic target in diffuse large B-cell lymphoma

Bruton tyrosine kinase inhibitor (BTKi) combined with rituximab-based chemotherapy benefits diffuse large B-cell lymphoma (DLBCL) patients. However, drug resistance is the major cause of relapse and death of DLBCL. In this study, we conducted a comprehensive analysis BTKi-resistance related genes (BRRGs) and established a 10-gene (CARD16, TRIP13, PSRC1, CASP1, PLBD1, CARD6, CAPG, CACNA1A, CDH15, and NDUFA4) signature for early identifying high-risk DLBCL patients. The resistance scores based on the BRRGs signature were associated with prognosis. Furthermore, we developed a nomogram incorporating the BRRGs signature, which demonstrated excellent performance in predicting the prognosis of DLBCL patients. Notably, tumor immune microenvironment, biological pathways, and chemotherapy sensitivity were different between high- and low-resistance score groups. Additionally, we identified TRIP13 as a key gene in our model. TRIP13 was found to be overexpressed in DLBCL and BTKi-resistant DLBCL cell lines, knocking down TRIP13 suppresses cell proliferation, promotes cell apoptosis, and enhances the apoptosis effect of BTKi on DLBCL cells by regulating the Wnt/β-catenin pathway. In conclusion, our study presents a novel BRRGs signature that could serve as a promising prognostic marker in DLBCL, and TRIP13 might be a potential therapeutic target for resistant DLBCL.

Ibrutinib as treatment for Bing–Neel syndrome reclassified as glioblastoma: a case report

BackgroundGlioblastoma is a highly malignant disease with limited treatment options. Ibrutinib, a covalent Bruton tyrosine kinase inhibitor, is an oral agent with manageable side effects used for hematological diseases including Waldenström macroglobulinemia. We present the case of a 69-year-old Caucasian male patient treated with ibrutinib for suspected Bing–Neel syndrome (BNS), which following a biopsy, was reclassified as glioblastoma.Case presentationIn December 2018, a 69-year-old Caucasian male patient was diagnosed with Waldenström macroglobulinemia. As the patient was asymptomatic, without bone marrow failure or high M-component count, watchful waiting was initiated. Due to increasing neurological symptoms, the patient, based on magnetic resonance imaging, was diagnosed with Bing–Neel syndrome in May 2019. The patient received different treatments before starting ibrutinib monotherapy in August 2019 due to disease progression, both on magnetic resonance imaging and clinically. The patient remained clinically stable for 7 months. In March 2020, the patient developed headaches, and both magnetic resonance imaging and a biopsy revealed glioblastoma IDH-wildtype. Treatment was changed in line with the new diagnosis, but the patient died at the end of 2020.ConclusionWe present a case in which a patient with glioblastoma IDH-wildtype remained clinically stable for 7 months when treated with ibrutinib monotherapy, which is similar to what would be expected for the standard treatment for glioblastoma. To our knowledge, this is the first patient receiving ibrutinib for a glioblastoma IDH-wildtype with a meaningful clinical outcome. Our case may therefore support previous nonclinical findings, indicating a therapeutic value of ibrutinib in patients with glioblastoma and support for further investigation of ibrutinib as a possible treatment for glioblastoma.

Exosomal miR-155-5p drives ibrutinib resistance in B-cell lymphoma

Ibrutinib, a Bruton Tyrosine Kinase (BTK) inhibitor, has shown effectiveness against various B-cell lymphoid malignancies. However, prolonged usage can induce resistance, affecting treatment outcomes. The oncogenic microRNA, miR-155-5p, is associated with poor prognosis in B-cell lymphomas, prompting our investigation into the mechanism of acquired ibrutinib resistance in these cells. We generated ibrutinib-resistant OCI-Ly1 cells (OCI-Ly1-IbtR) through continuous exposure to 1 μM and 2 μM of ibrutinib. We conducted microRNA profiling of OCI-Ly1-IbtR and isolated exosomes via ultracentrifugation. Comparative studies of microRNA levels in cells and exosomes, as well as exploration of targets of up-regulated microRNAs in OCI-Ly1-IbtR, were performed. Target validation involved transfection of candidate microRNAs, and co-culture experiments utilized OCI-Ly1 cells with exosomes from OCI-Ly1-IbtR. Elevated levels of miR-155-5p were observed in OCI-Ly1-IbtR and its exosomes, correlating with AKT and NF-κB activation. Transfection of miR-155-5p induced AKT/NF-κB pathway activation in OCI-Ly1, resulting in ibrutinib resistance, enhanced colony formation, and sustained BTK activity. Primary cell lines from ibrutinib-refractory B-cell lymphoma patients exhibited similar signaling protein activation. Target evaluation identified KDM5B and DEPTOR as miR-155-5p targets, confirmed by downregulation after transfection. We observed KDM5B and DEPTOR enrichment in Ago2 during ibrutinib resistance and miR-155-5p transfection. Co-culture experiments demonstrated exosome-mediated transfer of miR-155-5p, inducing ibrutinib resistance and KDM5B/DEPTOR downregulation in OCI-Ly1. Our findings suggest that miR-155-5p overexpression is associated with AKT and NF-κB pathway activation in ibrutinib-resistant cells, proposing a potential role for acquired miR-155-5p upregulation in B-cell lymphoma ibrutinib resistance.

Pre-existing cardiovascular disease is associated with an increased risk of cardiovascular events during Bruton tyrosine kinase inhibitor therapy.

The association between pre-existing cardiovascular disease (CVD) and the development of cardiovascular adverse events (CVAE) during Bruton tyrosine kinase inhibitor (BTKi) therapy is not well established. We compared the rate of CVAE, such as new onset or worsening atrial fibrillation (AF), supraventricular tachycardia, ventricular tachycardia, hypertension, myocardial infarction, and sudden cardiac death, between individuals with and without pre-existing CVD, during BTKi treatment. Secondary objectives were to compare the outcomes of patients treated with first generation BTKi versus second generation BTKi and characterize management decisions. A single-center retrospective review was conducted on patients treated with BTKi from 2013 to 2022 at Beth Israel Deaconess Medical Center. Adjusted logistic regression analyses were performed to evaluate the association between pre-existing CVD and CVAE. In this cohort, 11 out of 54 patients (20.4%) with pre-existing CVD developed CVAE, compared to 11 out of 135 patients (8.1%) without pre-existing CVD [age- and sex-adjusted OR 2.79; 95% CI (1.09, 7.25), P = .03]. Patients with pre-existing CVD had higher odds of developing new or worsening AF [age- and sex-adjusted OR 3.36; 95% CI (1.09, 10.71), P = .03]. Results remained robust after furtheradjustment of comorbidities, type of BTKi, and baseline medications. These results highlight the need for standardized approaches to prevent and promptly detect CVAE during BTKi treatment, particularly in patients with pre-existing CVD.

Patients with Waldenström macroglobulinemia have impaired platelet and coagulation function

AbstractClinical features in patients with the B-cell lymphoma, Waldenström macroglobulinemia (WM), include cytopenias, immunoglobulin M (IgM)–mediated hyperviscosity, fatigue, bleeding, and bruising. Therapeutics such as Bruton's tyrosine kinase inhibitors (BTKis) exacerbate bleeding risk. Abnormal hemostasis arising from platelet dysfunction, altered coagulation or vascular impairment have not yet been investigated in patients with WM. Therefore, this study aimed to evaluate hemostatic dysfunction in samples from these patients. Whole blood (WB) samples were collected from 14 patients with WM not receiving therapy, 5 patients receiving BTKis and 15 healthy donors (HDs). Platelet receptor levels and reticulation were measured by flow cytometry, plasma thrombin generation with or without platelets by fluorescence resonance energy transfer assay, WB clotting potential by rotational thromboelastometry, and plasma soluble glycoprotein VI (sGPVI) and serum thrombopoietin (TPO) by enzyme-linked immunosorbent assay. Donor platelet spreading, aggregation, and ability to accelerate thrombin generation in the presence of WM-derived IgM were assessed. WM platelet receptor levels, responses to physiological agonists, and plasma sGPVI were within normal ranges. WM platelets had reduced reticulation (P = .0012) whereas serum TPO levels were increased (P = .0040). WM plasma displayed slower thrombin generation (P = .0080) and WM platelets contributed less to endogenous thrombin potential (ETP; P = .0312). HD plasma or platelets incubated with IgM (50-60 mg/mL) displayed reduced spreading (P = .0002), aggregation (P < .0001), and ETP (P = .0081). Thus, alterations to thrombin potential and WB coagulation were detected in WM samples. WM IgM significantly impaired hemostasis in vitro. Platelet and coagulation properties are disturbed in patients with well-managed WM.

Pirtobrutinib, a highly selective, non-covalent (reversible) BTK inhibitor in patients with B-cell malignancies: analysis of the Richter transformation subgroup from the multicentre, open-label, phase 1/2 BRUIN study

Richter transformation usually presents as an aggressive diffuse large B-cell lymphoma, occurs in up to 10% of patients with chronic lymphocytic leukaemia, has no approved therapies, and is associated with a poor prognosis. Pirtobrutinib has shown promising efficacy and tolerability in patients with relapsed or refractory B-cell malignancies, including those who progress on covalent Bruton tyrosine kinase (BTK) inhibitors. This study aims to report the safety and activity of pirtobrutinib monotherapy in a subgroup of patients with Richter transformation from the multicentre, open-label, phase 1/2 BRUIN study. This analysis included adult patients (aged ≥18 years) with histologically confirmed Richter transformation, an Eastern Cooperative Oncology Group performance status score of 0-2, and no limit of previous therapies, with patients receiving first-line treatment added in a protocol amendment (version 9.0, Dec 15, 2021). Pirtobrutinib 200 mg was administered orally once a day in 28-day cycles. The primary endpoint of phase 1 of the BRUIN trial as a whole, which has been previously reported, was to establish the recommended phase 2 dose for pirtobrutinib monotherapy and the phase 2 primary endpoint was overall response rate. Safety and activity were measured in all patients who received at least one dose of pirtobrutinib monotherapy. This BRUIN phase 1/2 trial was registered with ClinicalTrials.gov and is closed to enrolment (NCT03740529). Between Dec 26, 2019, and July 22, 2022, 82 patients were enrolled, of whom five were enrolled during phase 1 and 77 during phase 2. All but one patient received a starting dose of 200 mg pirtobrutinib once a day as the recommended phase 2 dose. The remaining patient received 150 mg pirtobrutinib once a day, which was not escalated to 200 mg. The median age of patients was 67 years (IQR 59-72). 55 (67%) of 82 patients were male and 27 (33%) were female. Most patients were White (65 [79%] of 82). 74 (90%) of 82 patients received at least one previous Richter transformation-directed therapy. Most patients (61 [74%] of 82) had received previous covalent BTK inhibitor therapy for chronic lymphocytic leukaemia or Richter transformation. The overall response rate was 50·0% (95% CI 38·7-61·3). 11 (13%) of 82 patients had a complete response and 30 (37%) of 82 patients had a partial response. Eight patients with ongoing response electively discontinued pirtobrutinib to undergo stem-cell transplantation. The most common grade 3 or worse adverse event was neutropenia (n=19). There were no treatment-related deaths. Pirtobrutinib shows promising safety and activity among patients with Richter transformation, most of whom received previous Richter transformation-directed therapy, including covalent BTK inhibitors. These data suggest that further investigation is warranted of pirtobrutinib as a treatment option for patients with relapsed or refractory Richter transformation after treatment with a covalent BTK inhibitor. Loxo Oncology.

Bruton Tyrosine Kinase Inhibition Decreases Inflammation and Differentially Impacts Phagocytosis and Cellular Metabolism in Mouse- and Human-derived Myeloid Cells.

Bruton tyrosine kinase (BTK) is a kinase expressed by various immune cells and is often activated under proinflammatory states. Although the majority of BTK-related research has historically focused on B cells, understanding the role of BTK in non-B cell populations is critical given myeloid cells also express BTK at comparable levels. In this study, we investigated and compared how BTK inhibition in human and murine myeloid cells alters cell phenotype and function. All experiments were performed using two BTK inhibitors (evobrutinib and tolebrutinib) that are currently in late-stage clinical trials for the treatment of multiple sclerosis. Assays were performed to assess the impact of BTK inhibition on cytokine and microRNA expression, phagocytic capacity, and cellular metabolism. In all cells, both evobrutinib and tolebrutinib significantly decreased phosphorylated BTK and LPS-induced cytokine release. BTK inhibition also significantly decreased the oxygen consumption rate and extracellular acidification rate in myeloid cells, and significantly decreased phagocytosis in murine-derived cells, but not human macrophages. To further elucidate the mechanism, we also investigated the expression of microRNAs known to impact the function of myeloid cells. BTK inhibition resulted in an altered microRNA expression profile (i.e., decreased miR-155-5p and increased miR-223-3p), which is consistent with a decreased proinflammatory myeloid cell phenotype. In summary, these results provide further insights into the mechanism of action of BTK inhibitors in the context of immune-related diseases, while also highlighting important species-specific and cell-specific differences that should be considered when interpreting and comparing results between preclinical and human studies.

Assessment of the Efficacy and Safety of Acalabrutinib in Chronic Lymphocytic Leukemia (CLL): A Systematic Review and Meta‑Analysis .

Chronic lymphoid leukemia (CLL) is a common adult leukemia that has been treated with chemoimmunotherapy, which has significant toxicity among patients. Advances in CLL understanding have led to targeted therapies, such as Bruton's tyrosine kinase (BTK) inhibitors. Acalabrutinib is one of the second-generation BTK inhibitors and offers improved selectivity, reducing off-target effects. This systematic review and meta-analysis analyze data from multiple clinical trials to assess acalabrutinib efficacy and safety among patients with CLL. A literature search was carried out in PubMed, Cochrane Controlled Register of Trials (CENTRAL), MEDLINE (Medical Literature Analysis and Retrieval System Online), and Ovid databases for articles published until 2024. The outcomes included the overall response rate (ORR), complete response rate(CRR), 24-month progression-free survival rate, and grade ≥3 adverse events (AEs). Meta-analysis was performed using jamovi software. The search strategy yielded 823 records. After assessing the eligibility of the retrieved studies, the systematic review finally included six clinical trials, including 808 patients. The findings demonstrated significant efficacy of acalabrutinib, with a pooled ORR (P < 0.001) and a pooled CRR (P = 0.001). The pooled 24-month progression-free survival (PFS) rate showed a significant improvement in maintaining patient safety and treatment effectiveness (P <0.001). However, hematological AEs such as neutropenia, anemia, and thrombocytopenia were reported across studies. The pooled grade ≥ 3 AEs rate was 0.51 (95% CI: 0.21-0.81, I² = 98.21%, P <0.001), indicating a notable incidence of severe side effects. Acalabrutinib is an active drug in treating CLL that induces significant clinical benefits concerning response rates and PFS. However, acalabrutinib should be managed carefully to mitigate the risk of severe AEs. Further trials should be focused on assessing and modulating the safety of acalabrutinib.