Navigating the changing landscape of BTK-targeted therapies for B cell lymphomas and chronic lymphocytic leukaemia.

The B cell receptor (BCR) signalling pathway has an integral role in the pathogenesis of many B cell malignancies, including chronic lymphocytic leukaemia, mantle cell lymphoma, diffuse large B cell lymphoma and Waldenström macroglobulinaemia. Bruton tyrosine kinase (BTK) is a key node mediating signal transduction downstream of the BCR. The advent of BTK inhibitors has revolutionized the treatment landscape of B cell malignancies, with these agents often replacing highly intensive and toxic chemoimmunotherapy regimens as the standard of care. In this Review, we discuss the pivotal trials that have led to the approval of various covalent BTK inhibitors, the current treatment indications for these agents and mechanisms of resistance. In addition, we discuss novel BTK-targeted therapies, including covalent, as well as non-covalent, BTK inhibitors, BTK degraders and combination doublet and triplet regimens, to provide insights on the best current treatment paradigms in the frontline setting and at disease relapse.

Evaluation of bleeding risk in patients who received pirtobrutinib in the presence or absence of antithrombotic therapy.

Clinical bleeding events are reported here from 773 patients with B-cell malignancies receiving pirtobrutinib monotherapy from the phase 1/2 BRUIN study (ClinicalTrials.gov identifier: NCT03740529), either in the presence or absence of antithrombotic therapy (antithrombotic exposed [AT-E], n = 216; antithrombotic nonexposed [AT-NE], n = 557). Among the AT-E cohort, 51.9% received platelet aggregation inhibitors, 36.6% received direct factor Xa inhibitors, 18.5% received heparins, 5.6% received salicylic acid for indications other than platelet aggregation inhibition, and 2.3% received thrombolytics. Warfarin was not permitted. Any-grade bleeding/bruising events occurred in 97 patients (44.9%; 95% confidence interval [CI], 38.3-51.5) in the AT-E cohort and 181 patients (32.5%; 95% CI, 28.6-36.4) in the AT-NE cohort. Most bleeding/bruising events in both cohorts began within the first 6 months of treatment (AT-E: 65.4%; AT-NE: 72.5%). Contusion was the most common bleeding/bruising event in both cohorts (AT-E: 22.7%; AT-NE: 18.1%). Grade ≥3 bleeding/bruising events were reported in six patients (2.8%) in the AT-E cohort and 11 patients (2.0%) in the AT-NE cohort. Bleeding/bruising events requiring or prolonging hospitalization were reported in 2.3% and 1.6% of patients in the AT-E and AT-NE cohorts, respectively. No bleeding/bruising events led to pirtobrutinib dose reduction or permanent discontinuation in the AT-E cohort, and one patient (0.2%) in the AT-NE cohort experienced an event requiring dose reduction. These data support the safety of pirtobrutinib in patients requiring antithrombotic therapies.

Pirtobrutinib monotherapy in Bruton tyrosine kinase inhibitor-intolerant patients with B-cell malignancies: results of the phase I/II BRUIN trial.

Bruton tyrosine kinase inhibitors (BTKi) have transformed the treatment of B-cell malignancies, but intolerance has often led to their discontinuation. The phase 1/2 BRUIN study evaluated pirtobrutinib, a highly selective non-covalent (reversible) BTKi, in patients with R/R B-cell malignancies (NCT03740529). Pirtobrutinib was investigated in 127 patients with intolerance to at least one prior BTKi therapy in the absence of progressive disease. The most common adverse event (AE) leading to BTKi discontinuation was cardiac disorders (n=40, 31.5%), specifically atrial fibrillation (n=30, 23.6%). The median follow-up was 17.4 months and the median time on pirtobrutinib was 15.3 months. The most common reasons for pirtobrutinib discontinuation were progressive disease (26.8%), AE (10.2%), or death (5.5%). The most frequent treatment-emergent AEs were fatigue (39.4%) and neutropenia (37.0%). Among patients who discontinued a prior BTKi for a cardiac issue, 75% had no recurrence of their cardiac AE. No patient discontinued pirtobrutinib for the same AE that led to discontinuation of the prior BTKi. In 78 CLL/SLL and 21 MCL patients intolerant to prior BTKi, ORR to pirtobrutinib was 76.9% and 81.0%, respectively. Median PFS for CLL/SLL was 28.4 months and was not estimable for MCL. These results suggest that pirtobrutinib was safe, well-tolerated, and an efficacious option in patients with prior BTKi-intolerance.

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.

BACKGROUND: 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. METHODS: 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). FINDINGS: 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. INTERPRETATION: 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. FUNDING: Loxo Oncology.

Pirtobrutinib after a Covalent BTK Inhibitor in Chronic Lymphocytic Leukemia.

BACKGROUND: Patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) have poor outcomes after the failure of covalent Bruton's tyrosine kinase (BTK) inhibitor treatment, and new therapeutic options are needed. Pirtobrutinib, a highly selective, noncovalent (reversible) BTK inhibitor, was designed to reestablish BTK inhibition. METHODS: We conducted a phase 1-2 trial in which patients with relapsed or refractory B-cell cancers received pirtobrutinib. Here, we report efficacy results among patients with CLL or SLL who had previously received a BTK inhibitor as well as safety results among all the patients with CLL or SLL. The primary end point was an overall response (partial response or better) as assessed by independent review. Secondary end points included progression-free survival and safety. RESULTS: A total of 317 patients with CLL or SLL received pirtobrutinib, including 247 who had previously received a BTK inhibitor. Among these 247 patients, the median number of previous lines of therapy was 3 (range, 1 to 11), and 100 patients (40.5%) had also received a B-cell lymphoma 2 (BCL2) inhibitor such as venetoclax. The percentage of patients with an overall response to pirtobrutinib was 73.3% (95% confidence interval [CI], 67.3 to 78.7), and the percentage was 82.2% (95% CI, 76.8 to 86.7) when partial response with lymphocytosis was included. The median progression-free survival was 19.6 months (95% CI, 16.9 to 22.1). Among all 317 patients with CLL or SLL who received pirtobrutinib, the most common adverse events were infections (in 71.0%), bleeding (in 42.6%), and neutropenia (in 32.5%). At a median duration of treatment of 16.5 months (range, 0.2 to 39.9), some adverse events that are typically associated with BTK inhibitors occurred relatively infrequently, including hypertension (in 14.2% of patients), atrial fibrillation or flutter (in 3.8%), and major hemorrhage (in 2.2%). Only 9 of 317 patients (2.8%) discontinued pirtobrutinib owing to a treatment-related adverse event. CONCLUSIONS: In this trial, pirtobrutinib showed efficacy in patients with heavily pretreated CLL or SLL who had received a covalent BTK inhibitor. The most common adverse events were infections, bleeding, and neutropenia. (Funded by Loxo Oncology; BRUIN ClinicalTrials.gov number, NCT03740529.).

Pirtobrutinib in Covalent Bruton Tyrosine Kinase Inhibitor Pretreated Mantle-Cell Lymphoma.

PURPOSE: Pirtobrutinib is a highly selective, noncovalent (reversible) Bruton tyrosine kinase inhibitor (BTKi). We report the safety and efficacy of pirtobrutinib in patients with covalent Bruton tyrosine kinase inhibitor (cBTKi) pretreated mantle-cell lymphoma (MCL), a population with poor prognosis. METHODS: Patients with cBTKi pretreated relapsed/refractory (R/R) MCL received pirtobrutinib monotherapy in a multicenter phase I/II trial (BRUIN; ClinicalTrials.gov identifier: NCT03740529). Efficacy was assessed in the first 90 consecutively enrolled patients who met criteria for inclusion in the primary efficacy cohort. The primary end point was overall response rate (ORR). Secondary end points included duration of response (DOR) and safety. RESULTS: The median patient age was 70 years (range, 46-87), the median prior lines of therapy was 3 (range, 1-8), 82.2% had discontinued a prior cBTKi because of disease progression, and 77.8% had intermediate- or high-risk simplified MCL International Prognostic Index score. The ORR was 57.8% (95% CI, 46.9 to 68.1), including 20.0% complete responses (n = 18). At a median follow-up of 12 months, the median DOR was 21.6 months (95% CI, 7.5 to not reached). The 6- and 12-month estimated DOR rates were 73.6% and 57.1%, respectively. In the MCL safety cohort (n = 164), the most common treatment-emergent adverse events (TEAEs) were fatigue (29.9%), diarrhea (21.3%), and dyspnea (16.5%). Grade ≥3 TEAEs of hemorrhage (3.7%) and atrial fibrillation/flutter (1.2%) were less common. Only 3% of patients discontinued pirtobrutinib because of a treatment-related adverse event. CONCLUSION: Pirtobrutinib is a first-in-class novel noncovalent (reversible) BTKi and the first BTKi of any kind to demonstrate durable efficacy after prior cBTKi therapy in heavily pretreated R/R MCL. Pirtobrutinib was well tolerated with low rates of treatment discontinuation because of toxicity.

Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular Consensus on genetically modified cells. III: anti-CD19 CAR-T cell therapy for patients with non-Hodgkin lymphoma.

The treatment and evolution of B-cell non-Hodgkin lymphoma (B-NHL) has undergone important changes in the last years with the emergence of targeted therapies, such as monoclonal antibodies, small molecules, antibody-drug conjugates, and bispecific antibodies. Nevertheless, a significant portion of patients remains refractory or relapsed (R/R) to the new therapeutic modalities, representing thus an unmet medical need. The use of CAR-T cells for the treatment of B-NHL patients has shown to be a promising therapy with impressive results in patients with R/R disease. The expectations are as high as the imminent approval of CAR-T cell therapy in Brazil, which it is expected to impact the prognosis of R/R B-NHL. The aim of this manuscript is to offer a consensus of specialists in the field of onco-hematology and cellular therapy, working in Brazil and United States, in order to discuss and offer recommendations in the present setting of the use of CAR-T cells for patients with B-NHL.

Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular Consensus on genetically modified cells. I: Structuring centers for the multidisciplinary clinical administration and management of CAR-T cell therapy patients.

Chimeric antigen receptor T-cells (CAR-T cells) are a new modality of oncological treatment which has demonstrated impressive response in refractory or relapsed diseases, such as acute lymphoblastic leukemia (ALL), lymphomas, and myeloma but is also associated with unique and potentially life-threatening toxicities. The most common adverse events (AEs) include cytokine release syndrome (CRS), neurological toxicities, such as the immune effector cell-associated neurotoxicity syndrome (ICANS), cytopenias, infections, and hypogammaglobulinemia. These may be severe and require admission of the patient to an intensive care unit. However, these AEs are manageable when recognized early and treated by a duly trained team. The objective of this article is to report a consensus compiled by specialists in the fields of oncohematology, bone marrow transplantation, and cellular therapy describing recommendations on the Clinical Centers preparation, training of teams that will use CAR-T cells, and leading clinical questions as to their use and the management of potential complications.

R-MACLO-IVAM regimen followed by maintenance therapy induces durable remissions in untreated mantle cell lymphoma - Long term follow up results.

We present long-term combined results of two clinical trials implementing R-MACLO-IVAM induction followed by thalidomide or rituximab maintenance in 44 patients with untreated mantle cell lymphoma (MCL). The first 22 patients (UM-MCL1 ClinicalTrials.gov identifier NCT00450801) received maintenance with thalidomide (200 mg daily until relapse/intolerable toxicity) and a subsequent cohort of 22 patients (UM-MCL2 ClinicalTrials.gov identifier NCT00878254) received rituximab (375 mg/m2 IV weekly × 4, repeated every 6 months for 3 years). Considering all 44 patients, 41 (93.2%) achieved complete response (CR), two (4.5%) partial response (PR), and one (2.3%) was not evaluated for response. With a median follow up of 7.2 years (range < 1 month to 16 years), the 5-year progression-free survival (PFS) was 55.6% (95% CI: 38.9%-69.4%) and median PFS 7.9 years (95% CI: 3.7-11 years). The 5-year OS was 83.3% (95% CI: 68.1%-91.7%) and median OS was not reached. Patients with blastic variant (n = 6) had a 5-year PFS and OS of 20.8% and 60%, respectively. Myelosuppression was the most common adverse event during immunochemotherapy. Long-term treatment-related mortality was 6.8%. Note, R-MACLO-IVAM followed by maintenance therapy is an effective regimen to induce long-term remission in MCL without need for consolidation with ASCT.

Short survival and frequent transformation in extranodal marginal zone lymphoma with multiple mucosal sites presentation.

Between 11 and 37% of extranodal marginal zone lymphoma (EMZL) patients present with disease involvement in multiple mucosal sites (MMS). We analyzed 405 EMZL patients seen between 1995 and 2017: 265 (65.4%) patients presented with stage I disease, 49 of 309 (15.8%) patients with bone marrow involvement, and 35 of 328 (10.7%) patients with monoclonal gammopathy (MG). Forty-three (10.6%) patients had MMS presentation, which was more frequently seen in patients aged >60 years (55.8%). Five (17.9%) of 28 MMS patients had MG. MMS patients commonly exhibited the International Prognostic Index (IPI) >2 (79.1%), Follicular Lymphoma International Prognostic Index (FLIPI) >2 (39.5%), and Mucosa-Associated Lymphoid Tissue Lymphoma International Prognostic Index (MALT-IPI) 2-3 (60.5%). Both MMS presentation and MG were associated with shorter survival univariately. In multivariable Cox regression models, shorter progression-free survival (PFS) and overall survival (OS) were observed in patients with MMS (hazard ratio [HR] = 3.08 and 2.92, respectively), age ≥60 years (HR = 1.52 and 2.45, respectively), and in patients who failed to attain a complete remission following initial therapy (HR = 3.27 and 2.13, respectively). Elevated lactate dehydrogenase was associated with shorter PFS (HR = 1.92), while anemia (HR = 2.46) was associated with shortened OS. MALT-IPI ≥2 (HR = 2.47 and 4.75), FLIPI >2 (HR = 1.65 and 2.09), and IPI >2 (HR = 2.09 and 1.73) were associated with shorter PFS and OS, respectively. Higher grade transformation (HGT) occurred in 11 (25.6%) MMS patients with a 5-year cumulative incidence of 13.2% (95% CI 4.7-26.1%). EMZL patients with MMS presentation represent a novel clinical subset associated with shorter PFS, OS, and higher incidence of HGT that needs novel therapeutic approaches.

MiR-181 family-specific behavior in different cancers: a meta-analysis view.

The involvement of microRNAs in malignant transformation and cancer progression was previously grounded. The observations made by multiple published studies led to the conclusion that some of these small sequences could be eventually used as biomarkers for diagnosis/prognosis. This meta-analysis investigated whether microRNA-181 family members could predict the outcome of patients carrying different types of cancer. We searched the PubMed and Embase databases for studies evaluating the expression levels of miR-181a/b/c/d in patients with cancer, selecting the publications that assessed the relation between low and high levels of one of these four microRNAs and patients' outcome. Hazard ratios (HRs) or risk ratios (RRs) were extracted from the studies, and random-effect model was performed to investigate the role of miR-181 in the outcome of these patients. The meta-analysis comprised 26 studies including 2653 cancer patients from 6 countries. The results showed significant association between the expression of miR-181 family members and colorectal cancer. Considering the heterogeneity of the pathologies, the analysis, including all types of cancer and the expression of all the miR-181 family members together, showed no association with distinct outcome (HR = 1.099, p = 0.435). When the analysis was performed on each microRNA separately, the expression of miR-181c was significantly associated with the outcome of patients with cancer (HR = 2.356, p = 0.011) and miR-181a expression levels significantly correlated with survival in patients with non-small-cell lung cancer (HR = 0.177, p < 0.05). This meta-analysis revealed evidence regarding the involvement of miR-181 family members in the outcome of patients with some types of cancer, according to their expression level.

Prediction of survival in diffuse large B-cell lymphoma based on the expression of 2 genes reflecting tumor and microenvironment.

Several gene-expression signatures predict survival in diffuse large B-cell lymphoma (DLBCL), but the lack of practical methods for genome-scale analysis has limited translation to clinical practice. We built and validated a simple model using one gene expressed by tumor cells and another expressed by host immune cells, assessing added prognostic value to the clinical International Prognostic Index (IPI). LIM domain only 2 (LMO2) was validated as an independent predictor of survival and the "germinal center B cell-like" subtype. Expression of tumor necrosis factor receptor superfamily member 9 (TNFRSF9) from the DLBCL microenvironment was the best gene in bivariate combination with LMO2. Study of TNFRSF9 tissue expression in 95 patients with DLBCL showed expression limited to infiltrating T cells. A model integrating these 2 genes was independent of "cell-of-origin" classification, "stromal signatures," IPI, and added to the predictive power of the IPI. A composite score integrating these genes with IPI performed well in 3 independent cohorts of 545 DLBCL patients, as well as in a simple assay of routine formalin-fixed specimens from a new validation cohort of 147 patients with DLBCL. We conclude that the measurement of a single gene expressed by tumor cells (LMO2) and a single gene expressed by the immune microenvironment (TNFRSF9) powerfully predicts overall survival in patients with DLBCL.

MicroRNAs are independent predictors of outcome in diffuse large B-cell lymphoma patients treated with R-CHOP.

PURPOSE: Diffuse large B-cell lymphoma (DLBCL) heterogeneity has prompted investigations for new biomarkers that can accurately predict survival. A previously reported 6-gene model combined with the International Prognostic Index (IPI) could predict patients' outcome. However, even these predictors are not capable of unambiguously identifying outcome, suggesting that additional biomarkers might improve their predictive power. EXPERIMENTAL DESIGN: We studied expression of 11 microRNAs (miRNA) that had previously been reported to have variable expression in DLBCL tumors. We measured the expression of each miRNA by quantitative real-time PCR analyses in 176 samples from uniformly treated DLBCL patients and correlated the results to survival. RESULTS: In a univariate analysis, the expression of miR-18a correlated with overall survival (OS), whereas the expression of miR-181a and miR-222 correlated with progression-free survival (PFS). A multivariate Cox regression analysis including the IPI, the 6-gene model-derived mortality predictor score and expression of the miR-18a, miR-181a, and miR-222, revealed that all variables were independent predictors of survival except the expression of miR-222 for OS and the expression of miR-18a for PFS. CONCLUSION: The expression of specific miRNAs may be useful for DLBCL survival prediction and their role in the pathogenesis of this disease should be examined further.

CD25 expression is correlated with histological grade and response to denileukin diftitox in cutaneous T-cell lymphoma.

Denileukin diftitox (Ontak), a recombinant fusion protein of diphtheria toxin and ligand, IL-2, binds to the IL-2 receptor, is internalized, and causes cell death. Denileukin diftitox was approved for the treatment of cutaneous T-cell lymphomas (CTCLs) with CD25+ expression. We prospectively stained lesional skin biopsy specimens from 113 mycosis fungoides and Sézary Syndrome patients for activation markers CD25 and CD30 to correlate expression with clinical tumor-node metastasis (TNM) stage, histologic grade, and response to denileukin diftitox. High expression was defined as positivity of > or =20% of lesional T-cells using immunohistochemistry (IHC). CD25 and CD30 expression was more common in lesions from advanced patients (P = 0.04 and 0.002, respectively). Advanced TNM (T3 or T4) was significantly associated with intermediate-grade (P = 0.002) and large-cell transformation histology (P = 0.04). Of interest, clinical responses were observed in 78.5% of patients with high CD25 expression versus 20% with low to undetectable CD25 expression (P = 0.01) among 24 patients receiving standard 5-day infusions of denileukin diftitox at 18 microg/kg/day. These data suggest that high CD25 expression by IHC is associated with advanced CTCL and with clinical response to denileukin diftitox therapy.

Cardiac toxicity of alemtuzumab in patients with mycosis fungoides/Sézary syndrome.

Alemtuzumab is a monoclonal antibody to CD52 that has activity in T-cell leukemia and lymphoma. This study aims to describe the complications and outcomes of a subset of patients with mycosis fungoides/Sézary syndrome who were treated with alemtuzumab. Four of 8 patients, with no prior history of cardiac problems, developed significant cardiac toxicity (congestive heart failure or arrhythmia) that mostly improved after alemtuzumab discontinuation. The role of this agent in potentially inducing important cardiac side effects is suggested and argues for further investigation.