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.

The CNS relapse in T-cell lymphoma index predicts CNS relapse in patients with T- and NK-cell lymphomas.

ABSTRACT: Little is known about risk factors for central nervous system (CNS) relapse in mature T-cell and natural killer cell neoplasms (MTNKNs). We aimed to describe the clinical epidemiology of CNS relapse in patients with MTNKN and developed the CNS relapse In T-cell lymphoma Index (CITI) to predict patients at the highest risk of CNS relapse. We reviewed data from 135 patients with MTNKN and CNS relapse from 19 North American institutions. After exclusion of leukemic and most cutaneous forms of MTNKNs, patients were pooled with non-CNS relapse control patients from a single institution to create a CNS relapse-enriched training set. Using a complete case analysis (n = 182), including 91 with CNS relapse, we applied a least absolute shrinkage and selection operator Cox regression model to select weighted clinicopathologic variables for the CITI score, which we validated in an external cohort from the Swedish Lymphoma Registry (n = 566). CNS relapse was most frequently observed in patients with peripheral T-cell lymphoma, not otherwise specified (25%). Median time to CNS relapse and median overall survival after CNS relapse were 8.0 and 4.7 months, respectively. We calculated unique CITI risk scores for individual training set patients and stratified them into risk terciles. Validation set patients with low-risk (n = 158) and high-risk (n = 188) CITI scores had a 10-year cumulative risk of CNS relapse of 2.2% and 13.4%, respectively (hazard ratio, 5.24; 95% confidence interval, 1.50-18.26; P = .018). We developed an open-access web-based CITI calculator (https://redcap.link/citicalc) to provide an easy tool for clinical practice. The CITI score is a validated model to predict patients with MTNKN at the highest risk of developing CNS relapse.

Racial disparities in chronic lymphocytic leukemia/small lymphocytic lymphoma accounting for small molecule inhibitors: A real-world cohort analysis.

Kaplan-Meier curve depicting overall survival from CLL treatment start by race. For patients with CLL, no overall survival difference was observed between races in this real-world US database.

Kinase-impaired BTK mutations are susceptible to clinical-stage BTK and IKZF1/3 degrader NX-2127.

Increasing use of covalent and noncovalent inhibitors of Bruton's tyrosine kinase (BTK) has elucidated a series of acquired drug-resistant BTK mutations in patients with B cell malignancies. Here we identify inhibitor resistance mutations in BTK with distinct enzymatic activities, including some that impair BTK enzymatic activity while imparting novel protein-protein interactions that sustain B cell receptor (BCR) signaling. Furthermore, we describe a clinical-stage BTK and IKZF1/3 degrader, NX-2127, that can bind and proteasomally degrade each mutant BTK proteoform, resulting in potent blockade of BCR signaling. Treatment of chronic lymphocytic leukemia with NX-2127 achieves >80% degradation of BTK in patients and demonstrates proof-of-concept therapeutic benefit. These data reveal an oncogenic scaffold function of mutant BTK that confers resistance across clinically approved BTK inhibitors but is overcome by BTK degradation in patients.

Combining Super Learner with high-dimensional propensity score to improve confounding adjustment: A real-world application in chronic lymphocytic leukemia.

PURPOSE: High-dimensional propensity score (hdPS) is a semiautomated method that leverages a vast number of covariates available in healthcare databases to improve confounding adjustment. A novel combined Super Learner (SL)-hdPS approach was proposed to assist with selecting the number of covariates for propensity score inclusion, and was found in plasmode simulation studies to improve bias reduction and precision compared to hdPS alone. However, the approach has not been examined in the applied setting. METHODS: We compared SL-hdPS's performance with that of several hdPS models, each with prespecified covariates and a different number of empirically-identified covariates, using a cohort study comparing real-world bleeding rates between ibrutinib- and bendamustine-rituximab (BR)-treated individuals with chronic lymphocytic leukemia in Optum's de-identified Clinformatics® Data Mart commercial claims database (2013-2020). We used inverse probability of treatment weighting for confounding adjustment and Cox proportional hazards regression to estimate hazard ratios (HRs) for bleeding outcomes. Parameters of interest included prespecified and empirically-identified covariate balance (absolute standardized difference [ASD] thresholds of <0.10 and <0.05) and outcome HR precision (95% confidence intervals). RESULTS: We identified 2423 ibrutinib- and 1102 BR-treated individuals. Including >200 empirically-identified covariates in the hdPS model compromised covariate balance at both ASD thresholds. SL-hdPS balanced more covariates than all individual hdPS models at both ASD thresholds. The bleeding HR 95% confidence intervals were generally narrower with SL-hdPS than with individual hdPS models. CONCLUSION: In a real-world application, hdPS was sensitive to the number of covariates included, while use of SL for covariate selection resulted in improved covariate balance and possibly improved precision.

MRD-directed therapy in CLL: ready for prime time?

In recent years, the treatment paradigm for patients with chronic lymphocytic leukemia (CLL) has moved away from chemoimmunotherapy (CIT) toward the use of novel targeted agents. Commercially available drugs, including Bruton's tyrosine kinase inhibitors and the BCL2 inhibitor venetoclax, often used in combination with anti-CD20 monoclonal antibodies, are now the mainstay of therapy both in the frontline and in relapsed settings. As the landscape for CLL management evolves, therapeutic endpoints need to be redefined. Detection of measurable residual disease (MRD) is a sensitive tool to identify disease burden following treatment with several therapeutic regimens in CLL (including CIT, venetoclax-based regimens, and cellular therapies), and it has demonstrated prognostic value. Despite recent advances, the utility of MRD-directed therapy and attempts to eradicate it in routine clinical practice remain debated. There is little comparative data from clinical trials on the best assay to determine undetectable MRD (U-MRD) and whether its monitoring can lead to changes in treatment strategies. Our review discusses the definitions of MRD, assays for its detection, and its impact on long-term survival outcomes for patients with a CLL diagnosis.

Results from a Real-World Multicenter Analysis of 482 Patients with Chronic Lymphocytic Leukemia Treated with Ibrutinib: A Look at Racial Differences.

BACKGROUND: Despite recent approvals of lifesaving treatments for chronic lymphocytic leukemia (CLL), real-world data on the tolerability of the Bruton tyrosine kinase inhibitor ibrutinib for CLL treatment are lacking, especially in Black patients. OBJECTIVE: To expand upon a previously reported retrospective chart review of ibrutinib-treated patients with CLL to increase the number of sites and the enrollment period in first-line (1L) and relapsed/refractory (R/R) settings with a subanalysis based on ethnicity. PATIENTS AND METHODS: Adults with CLL who initiated ibrutinib treatment from five centers were followed for ≥ 6 months. RESULTS: We identified 482 patients with CLL [405 White (153 1L, 252 R/R), 37 Black (17 1L, 20 R/R), 40 other/unidentified]. At baseline, 58.5% of all patients (68.8% of Black patients) had hypertension. At a median follow-up of 28.2 months, 31.1% of patients overall discontinued ibrutinib, 16.2% due to adverse events (12.2% 1L, 18.8% R/R). Overall, 46.0% of patients experienced ≥ 1 dose hold (40.2% 1L, 49.8% R/R), and 28.8% of patients experienced ≥ 1 dose reduction (24.9% 1L, 31.4% R/R). Among Black patients, ibrutinib was discontinued in 24.3% of patients (17.6% 1L, 30.0% R/R), 8.1% due to disease progression and 5.4% due to adverse events; 40.5% of patients experienced ≥ 1 dose hold (35.3% 1L, 45.0% R/R), and 32.4% of patients experienced ≥ 1 dose reduction (23.5% 1L, 40.0% R/R). CONCLUSIONS: Toxicity and disease progression were the most common reasons for ibrutinib discontinuations in the overall population and among Black patients, respectively. Encouraging research participation of underrepresented patient groups will help clinicians better understand treatment outcomes.

Ibrutinib, a Bruton tyrosine kinase inhibitor, is an approved oral targeted therapy for the treatment of chronic lymphocytic leukemia (CLL). Patients treated with ibrutinib can experience side effects (referred to as adverse events) and may need to reduce the drug dose (referred to as dose reductions) or stop treatment (referred to as discontinuations) for a variety of reasons. A previous study showed that patients who were treated with ibrutinib experienced frequent dose reductions and discontinuations. This study described dose reductions and discontinuations in a larger patient population treated with ibrutinib and also described outcomes in Black patients. Patients with CLL treated with ibrutinib were identified from five medical centers and were followed for a minimum of 6 months. Patients experienced frequent dose reductions and discontinuations in routine clinical practice. The most common cause of discontinuations was adverse events in the overall patient population and disease progression in the Black patient population. Black patients treated with ibrutinib had similar rates of dose reductions and discontinuations as the overall patient population. Rates of dose reductions and discontinuations for patients with CLL treated with ibrutinib were higher in this real-world study than in clinical trials.

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.).

Vaccination efficacy in patients with chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is a disorder of mature malignant B cells with multiple elements of immune dysfunction. Infections are common in CLL patients due to complex immunodeficiency. Vaccines are used as preventative measures for common diseases including influenza, pneumococcus, tetanus/diphtheria and shingles in the general population. Vaccines are utilized to mitigate this risk, although there have been some concerns regarding the efficacy of vaccines in the CLL population due to the inherent complex immune dysfunction associated with the disease. In this review, we describe the clinical and laboratory indicators for efficacy of the vaccines in the CLL population (including COVID-19, influenza, pneumonia, herpes zoster, and tetanus) and discuss immunization recommendations for patients with CLL.

How Have Targeted Agents Changed the Treatment Landscape for Elderly Patients with CLL?

PURPOSE OF REVIEW: Chronic lymphocytic leukemia (CLL) is a common hematologic malignancy in elderly patients. At the time of diagnosis, most patients have comorbid medical conditions. Although patients have other competing medical issues, the majority of patients will die from CLL or CLL-related complications. This review will discuss treatment in elderly patients with CLL. RECENT FINDINGS: Recent work has focused on understanding the role comorbid medical conditions play in the management of CLL in elderly patients, including the use of geriatric assessment, Charlson comorbidity index, cumulative illness rating scale, and most recently, the CLL-comorbidity index. The treatment landscape for CLL has shifted from chemoimmunotherapy to the use of targeted agents. Several clinical trials in elderly patients have demonstrated improvement in progression-free survival (PFS) with ibrutinib + / - obinutuzumab, acalabrutinib + / - obinutuzumab, zanubrutinib, venetoclax-obinutuzumab, idelalisib, and duvelisib. The adverse event profile and potential for drug-drug interactions in the treatment of CLL in elderly patients have not been described, and further studies are needed to determine optimal treatment. Treatment of elderly patients with CLL should be made on a case-by-case basis based on a patient's fitness, comorbid medical conditions, and concomitant medications. The use of targeted agents has improved outcomes in this patient population, but further studies are needed to determine the best practice.

Zanubrutinib (BGB-3111), a Second-Generation Selective Covalent Inhibitor of Bruton's Tyrosine Kinase and Its Utility in Treating Chronic Lymphocytic Leukemia.

The understanding of the B cell receptor (BCR) pathway and its contribution to chronic lymphocytic leukemia (CLL) pathogenesis have led to the development of targeted BCR inhibitors which have transformed the treatment paradigm of CLL. Ibrutinib is a first-in-class oral Bruton's tyrosine kinase (BTK) inhibitor which has demonstrated improvements in both progression free (PFS) and overall survival (OS) in both the treatment naïve and relapsed/refractory setting as compared to traditional chemoimmunotherapy. Despite its clinical efficacy, many patients discontinue treatment due to adverse events, which are thought to be mediated through off-target kinase inhibition. Zanubrutinib is a second-generation non-covalent BTK inhibitor with higher potency, allowing for inhibition of BTK with fewer off target effects. Early phase clinical trials have demonstrated excellent efficacy and a well-tolerated safety profile. Long-term follow-up is needed, but zanubrutinib holds promise to be an effective therapy for CLL with a manageable side effect profile and will be an exciting addition to our treatment paradigm.

Chemotherapy-free frontline therapy for CLL: is it worth it?

The treatment of chronic lymphocytic leukemia (CLL) embodies one of the great success stories in translational research, with the development of therapies aimed at disrupting crucial pathways that allow for the survival and proliferation of the malignant clone. The arrival of targeted agents into our armamentarium, along with the advent of novel monoclonal antibodies that can achieve deeper remissions, has steered the field to a new treatment paradigm. Given the panoply of therapeutic options available, the question arises whether chemotherapy still has a role in the management of CLL. The novel targeted agents, which include the Bruton's tyrosine kinase inhibitors, ibrutinib and acalabrutinib, along with the B-cell lymphoma-2 inhibitor, venetoclax, are highly effective in achieving a response with improved remission duration and survival, particularly in high-risk patients. Despite this major progress, the new agents bring a unique set of toxicities unlike those associated with cytotoxic chemotherapy. There is a paucity of head-to-head comparisons among all of the novel agents, because their approval was based on randomization against traditional chemoimmunotherapeutic regimens. Parallel to the increase in the number of available targeted agents, there has been a significant improvement in quality of life and life expectancy of the patients with a CLL diagnosis over the last decade. Our review will examine whether "chemotherapy-free" frontline treatment approaches are worth the associated risks. Our goal is to help identify optimal treatment strategies tailored to the individual by reviewing available data on monotherapy vs combination strategies, depth of response, treatment duration, and potential toxicities.

Ibrutinib-associated Arthralgias/Myalgias in Patients With Chronic Lymphocytic Leukemia: Incidence and Impact on Clinical Outcomes.

INTRODUCTION: The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib has transformed the treatment of chronic lymphocytic leukemia (CLL), leading to unprecedented improvements in progression-free and overall survival for all patients, including those with poor prognostic features. The side effect profile of ibrutinib is unique compared with chemoimmunotherapy and includes atrial fibrillation, increased bleeding risk, and arthralgias/myalgias. Although common, arthralgias/myalgias and their management are poorly described. PATIENTS AND METHODS: We identified 214 patients with CLL treated with ibrutinib (as a single agent or in combination) from 2011 to 2018 at the University of Pennsylvania. RESULTS: In this cohort, 36% (76/214) of patients developed arthralgias/myalgias during follow-up with a median onset of 34.5 months. Most (79%) events were grade 1 or 2. Risk factors for developing arthralgias/myalgias included younger age at start of ibrutinib, female gender, and ibrutinib use as first treatment. Twenty-eight percent of patients with grade 1 or 2 toxicity continued ibrutinib and had resolution of symptoms. Dose holds were frequently used to manage this toxicity, and this strategy was more successful than dose reduction. Sixty-two percent of patients with grade 3 toxicity ultimately discontinued ibrutinib. Supportive care measures such as discontinuing statins or use of non-steroidal anti-inflammatory drugs, acetaminophen, or corticosteroids were not used frequently enough in this cohort to evaluate their efficacy. CONCLUSIONS: Additional studies to determine the mechanism of ibrutinib-related arthralgias/myalgias are needed to develop optimal management strategies.

Chimeric Antigen Receptor T Cells in Chronic Lymphocytic Leukemia: Are We Any Closer to a Cure?

Recent advances in the treatment of chronic lymphocytic leukemia (CLL) have dramatically changed outcomes for patients. Despite these improvements, CLL is still considered incurable. Chimeric antigen receptor-modified T cells have demonstrated the ability to produce long-term remissions in subsets of heavily pretreated patients with B-cell malignancies, including CLL. Unfortunately, the majority of patients with CLL do not attain durable responses. Recent studies have focused on understanding the mechanisms and predictors of response in these patients. In this review, we will discuss the literature for chimeric antigen receptor-modified T-cell therapy in CLL and highlight mechanisms of response and resistance as currently understood.

PET/Computed Tomography in Chronic Lymphocytic Leukemia and Richter Transformation.

Chronic lymphocytic leukemia (CLL) is the most common leukemia in the United States. In 1-10% of cases, it can undergo Richter's transformation (RT) to either diffuse large B cell lymphoma (DLBCL) or Hodgkin's lymphoma (HL). Diagnosis requires histologic confirmation by tissue biopsy. PET/CT has been studied to in several series to look at its predictive value for identifying RT in biopsies. in this review, we will discuss the role of PET/CT to identify RT in patients CLL and its utility in clinical practice.

Management of giant cell hepatitis associated with chronic lymphocytic leukemia - a case series and review of the literature.

Giant cell hepatitis (GCH) is a rare diagnosis in adults that is found in 0.25% of liver biopsies. GCH has been associated with multiple causes including drugs (6-mercaptopurine, methotrexate), toxins, viruses and autoimmune. GCH has been described in few patients with chronic lymphocytic leukemia (CLL). Here we describe three patients diagnosed with GCH thought to be related to underlying CLL and its management. All of our patients were treated with a combination of immunosuppression as well as CLL-directed therapy to address CLL and concomitant liver disease. GCH is a rare manifestation of active CLL and should be ruled out with prompt liver biopsy in patients with CLL with persistent transaminitis without another attributable cause. Prompt treatment of GCH with immunosuppression is required to prevent long-term liver toxicity. If transaminitis does not improve with immunosuppression alone, the addition of CLL directed therapy should be considered in patients who carry this diagnosis to prevent long-term liver toxicity.