Ibrutinib Regimens versus Chemoimmunotherapy in Older Patients with Untreated CLL

Flow Cytometric MRD Detection in Selected Mature B-Cell Malignancies

The quantification of submicroscopic minimal residual disease (MRD) after therapy proved to have independent prognostic significance in many mature B-cell malignancies. With the advent of routine benchtop cytometers capable of simultaneously analyzing ≥8 colors and with improved standardization, flow cytometry has become the method of choice for MRD assessments in some lymphoma entities. Herein we describe general aspects of flow cytometric standardization. Chronic lymphocytic leukemia (CLL) and multiple myeloma (MM) are used as examples to explain the technical standardization of flow cytometry for MRD detection according to EuroFlow strategies. MRD data acquisition and detailed analysis in MM and CLL is a particular focus of this chapter.

Phase III Evaluation of Treatment Combinations in Three-Arm Trials

Phase III trials that randomly assign patients to a control treatment (C), an experimental treatment (A), or a combination treatment (AB) should be designed with the goal to recommend the best treatment: AB (if it is better than A and C), A (if it is better than C, and AB is not better than A), or C (if neither AB nor A is better than C). However, this goal can be challenging to achieve with statistical confidence. We performed a survey of cancer trials published in five journals from January 2018 to May 2024 to assess the trial designs being used in this setting and found that three quarters of them did not have a provision for a formal comparison of the AB treatment arm with the A treatment arm, a possible shortcoming. A limited simulation evaluates two analysis strategies that incorporate an AB versus A comparison and is used to formulate some recommendations for designing these types of trials.

Recent Advances in the Molecular Biology of Chronic Lymphocytic Leukemia: How to Define Prognosis and Guide Treatment

Chronic Lymphocytic Leukemia (CLL) is the most frequent type of leukemia in Western countries. In recent years, there have been important advances in the knowledge of molecular alterations that underlie the disease's pathogenesis. Very heterogeneous prognostic subgroups have been identified by the mutational status of immunoglobulin heavy variable genes (IGVH), FISH analysis and molecular evaluation of TP53 mutations. Next-generation sequencing (NGS) technologies have provided a deeper characterization of the genomic and epigenomic landscape of CLL. New therapeutic targets have led to a progressive reduction of traditional chemoimmunotherapy in favor of specific biological agents. Furthermore, in the latest clinical trials, the minimal residual disease (MRD) has emerged as a potent marker of outcome and a guide to treatment duration. This review focuses on recent insights into the understanding of CLL biology. We also consider the translation of these findings into the development of risk-adapted and targeted therapeutic approaches.

The role of antibody therapies in treating relapsed chronic lymphocytic leukemia: a review

INTRODUCTION

Chronic lymphocytic leukemia (CLL) is one of the most common types of leukemia in adult patients. The landscape of CLL therapy has changed in the last decades with the introduction of antibody-based therapies and novel targeted agents resulting in improved outcomes.

AREAS COVERED

This article describes the use of monoclonal antibodies, bispecific antibodies and antibody-drug conjugates in the treatment of relapsed and refractory CLL. The mechanism of action and clinical applications and safety of antibody-based therapies, both as monotherapy and in combination with other drugs, are discussed. A literature search was performed using PubMed, Web of Science, and Google Scholar for articles published in English. Additional relevant publications were obtained by reviewing the references from the chosen articles.

EXPERT OPINION

Antibody-based therapeutic strategies have drastically changed the treatment of CLL, as they have introduced the concept of boosting immune responses against tumor cells. While immunotherapy is generally effective, some treatment failure can occur due to antigen loss, mutation, or down-regulation, and this remains the main obstacle to cure. The development of novel antibody therapies, including their combinations with targeted drugs and bispecific antibodies, might help to reduce toxicity and improve efficacy.

Utilizing risk factors to guide treatment decisions in chronic lymphocytic leukemia

INTRODUCTION

In the era of chemo-immunotherapy, high-risk factors unequivocally predicted inferior outcomes for patients with CLL. The widespread adoption of BTK inhibitors has challenged the practical implications of such testing, as many patients have improved outcomes despite the presence of high-risk features. The impact of adverse prognostic factors, such as unmutated IGHV, on survival has been ameliorated by continuous treatment with BTK inhibitors, but not by finite-duration therapy with venetoclax-based combinations. Furthermore, TP53 abnormalities continue to be associated with worse outcomes in the era of novel agents. New treatment modalities, such as pirtobrutinib, lisocabtagene maraleucel, and ongoing studies combining BTK inhibitors with venetoclax, raise new questions on the significance of prognostic factors of survival for patients with CLL.

AREAS COVERED

Herein, we summarized the available literature on patients with CLL harboring high-risk biomarkers, with a focus on data from key clinical trials.

EXPERT OPINION

Testing for prognostic biomarkers will remain relevant to identify patients who may have increased benefit from novel therapeutic strategies, such as combination therapies and novel agents. Patients with high-risk disease should be encouraged to participate in clinical trials.

Atrial fibrillation burden and clinical outcomes following BTK inhibitor initiation

Bruton's tyrosine kinase inhibitors (BTKi) have dramatic efficacy against B-cell malignancies, but link with cardiotoxicity, including atrial fibrillation (AF). Burden, severity, and implications of BTKi-related AF are unknown. Leveraging a large-cohort of consecutive B-cell malignancy patients initiated on BTKi from 2009-2020, we identified patients with extended ambulatory rhythm monitoring. The primary outcome was AF burden after BTKi-initiation. Secondary outcomes included ventricular arrhythmia burden and other arrhythmias. Observed incident-AF rates and burden with next-generation BTKi's were compared to ibrutinib. Multivariable regression defined association between rhythm measures and major adverse cardiac events (MACE), and mortality. There were 98 BTKi-treated patients [38.8% next-generation BTKi's, 14.3% prior-AF], with 28,224 h of monitoring. Median duration BTKi-use was 34 months. Over mean duration 12 days monitoring, 72.4% developed arrhythmias (16.3% incident-AF, 31.6% other SVTs, 14.3% ventricular tachycardia). 14.3% had high AF-burden. AF-burden was similar between ibrutinib and next-generation BTKi's. No single antiarrhythmic-therapy prevented BTKi-related AF. However, antiarrhythmic initiation associated with reduction in arrhythmic burden (P = 0.009). In a multivariable model accounting for traditional cardiovascular risk factors, prior-AF associated with increased post-BTKi AF-burden. In follow-up, high AF burden associated with MACE (HR 3.12, P = 0.005) and mortality (HR 2.97, P = 0.007). Among BTKi-treated patients, high AF burden prognosticates future MACE and mortality risk.

Pericardial events associated with ibrutinib-based therapies for chronic lymphocytic leukaemia in two landmark trials

In the past decade, ibrutinib has transformed the treatment landscape for chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Two pivotal US Intergroups trials (E1912 and A041202) have established ibrutinib as the frontline treatment option for patients with treatment-naïve CLL in both young and fit, and old and frail populations. The cardiovascular side effect profile such as cardiac dysrhythmias, ischemic events and hypertension continues to be meticulously reported in all trials investigating ibrutinib and all other Bruton tyrosine kinase inhibitors for CLL/SLL. Herein, we utilized pooled data from two pivotal US Intergroup trials (A041202 and E1912) to report and evaluate ibrutinib associated pericardial events (including pericardial effusion, pericarditis, and tamponade).

Current Approaches and Novel Agents in the Treatment of Chronic Lymphocytic Leukemia

The treatment of CLL has evolved from traditional chemoimmunotherapy (CIT) to an increasing number of targeted and biologic approaches. Randomized trials have demonstrated superiority of covalent bruton tyrosine kinase inhibitors (cBTKis) over CIT, and second-generation compounds such as acalabrutinib and zanubrutinib appear to have a more favorable efficacy/safety profile than ibrutinib. The noncovalent BTKi, pirtobrutinib, has shown impressive activity after failure of the cBTKis and is quite tolerable. The Bcl-2 inhibitor venetoclax plus a CD20, generally obinutuzumab, provides a high level of efficacy as initial treatment or after failure on a cBTKi, with many patients achieving a state of undetectable minimal residual disease. Promising novel approaches include BTK degraders, bispecific antibodies, and chimeric antigen receptor T-cell (CAR-T)-cell therapy. What is clear is that CIT is archaic, and current and future targeted approaches will continue to improve the outcome for patients with chronic lymphocytic leukemia.

Are small lymphocytic lymphoma and chronic lymphocytic leukemia the same disease? The unsolved dilemma

The management of small lymphocytic lymphoma (SLL) as chronic lymphocytic leukemia (CLL) or an indolent non-Hodgkin lymphoma is highly debated. In this single-center, real-life study, 38 SLL patients managed between 2008 and 2022 were evaluated. Overall, 26/38 cases (68.4%) needed treatment and all but one received CLL concordant therapy, including BR (9/38 cases), fludarabine, cyclophosphamide, rituximab (5/38 cases), rituximab and chlorambucil (4/38 cases), BTK inhibitors (7/38 cases) and steroid (1 case with immune thrombocytopenia). Patients treated between 2008 and 2018 were more likely to receive chemoimmunotherapy compared to patients treated in 2019-2022, that were more likely to receive BTK inhibitors. The median PFS was 54 months and 3-y PFS was 58%, while the median OS was not reached, with a 3-y OS of 84%. We confirm a wide heterogeneity in SLL management and we suggest prospective studies are needed to improve the knowledge of its biology and harmonize its treatment.

BTK inhibitors: moving the needle on the treatment of chronic lymphocytic leukemia

INTRODUCTION

Bruton's tyrosine kinaseinhibitors (BTKis) changed the trajectory of upfront and relapsed/refractory chronic lymphocytic leukemia (CLL) treatment. However, BTKis are plagued by a spectrum of toxicities. Zanubrutinib was developed to circumvent challenges with prolonged tolerability by increasing BTK selectivity and maximizing efficacy through pharmacokinetic/pharmacodynamic optimization. However, with the availability of ibrutinib, acalabrutinib, and zanubrutinib, limited data exists to guide sequencing of BTKi therapy in the relapsed/refractory setting.

AREAS COVERED

We review the first head-to-head trial (ALPINE) of zanubrutinib versus ibrutinib for the treatment of relapsed/refractory CLL and compare zanubrutinib's clinical efficacy and toxicities, including in patients with del(17p) and/or TP53 mutations to ibrutinib and acalabrutinib.

EXPERT OPINION

Zanubrutinibrepresents one of the new standards of care for relapsed/refractory CLL based on superior progression-free survival and response rates over ibrutinib. Whilezanubrutinib is associated with fewer cardiac toxicities, similar rates of neutropenia and hypertension are noted. Ongoing studies are pushing the envelope, utilizing targeted drug combinations and minimal residual disease markers as well as receptor tyrosine kinase-like orphan receptor 1 inhibitors, chimeric antigen receptor T-cells, and novel BTK degraders. However, zanubrutinibrepresents a strong contender in the arsenal of treatment options for relapsed/refractory CLL.

Real-world comparison of health care costs of venetoclax-obinutuzumab vs Bruton's tyrosine kinase inhibitor use among US Medicare beneficiaries with chronic lymphocytic leukemia in the frontline setting

BACKGROUND

Bruton's tyrosine kinase inhibitors (BTKis) and the BCL-2 inhibitor venetoclax in combination with obinutuzumab (VEN-O) are both recommended as frontline therapy in chronic lymphocytic leukemia (CLL). However, VEN-O is a 12-month fixed-duration therapy generating durable remissions whereas BTKis are continuous treat-to-progression treatments.

OBJECTIVE

To examine costs before and after the fixed-duration treatment period for VEN-O relative to that observed for BTKis in a national sample of older US adults with CLL in the frontline setting.

METHODS

This retrospective analysis used Medicare Parts A, B, and D claims from 2016 to 2021. Fee-for-service Medicare beneficiaries aged 66 years or older initiating frontline CLL treatment with VEN-O or a BTKi treatment between June 1, 2019, and June 30, 2020 (index date = first prescription fill date), were included in the sample. Mean cost measures were captured for both groups over 2 fixed time periods calculated from the index date: Month 0 to 12 (proxy for VEN-O on-treatment period) and Month 13 to 18 (proxy for VEN-O off-treatment period). A difference-in-difference approach was used. Multivariate generalized linear models estimated changes in adjusted mean monthly costs during Month 0 to 12 vs Month 13 to 18, for the VEN-O group relative to the BTKi group.

RESULTS

The final sample contained 193 beneficiaries treated with VEN-O and 1,577 beneficiaries treated with BTKis. Risk-adjusted all-cause monthly total costs were similar for VEN-O patients ($13,887) and BTKi patients ($14,492) between Month 0 and 12. Moreover, during Month 13 to 18, the mean monthly all-cause total costs declined by 67% for VEN-O ($13,887 to $4,462) but only by 10% for BTKi ($14,492 to $13,051). Hence, the relative reduction in costs across the 2 periods was significantly larger for VEN-O (-$9,425) vs BTKi (-$1,441) patients (ie, difference in difference = -$7,984; P < 0.001). Similar patterns were observed for CLL-related costs, with the substantially larger reductions in CLL-related total monthly costs (-$9,880 VEN-O vs -$1,753 BTKi; P < 0.001) for the VEN-O group primarily driven by the larger reduction in CLL-related monthly prescription costs (-$9,437 VEN-O vs -$2,020 BTKi; P < 0.001).

CONCLUSIONS

This real-world study of older adults with CLL found a large reduction in monthly Medicare costs in the 6 months after completion of the fixed-duration treatment period of VEN-O, largely driven by the reduction in CLL-related prescription drug costs. A similar decline in costs was not observed among those treated with BTKis. Our study highlights the substantial economic benefits of fixed-duration VEN-O relative to treat-to-progression therapies like BTKis in the first-line CLL setting.

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

BACKGROUND

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.

METHODS

A 10-year partitioned survival model was developed, considering key clinical parameters and direct medical costs. Results were stratified by TP53 aberration.

RESULTS

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.

CONCLUSIONS

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.

Management of infections for patient treated with ibrutinib in clinical practice

Ibrutinib, a highly effective inhibitor of the Bruton tyrosine kinase, has significantly transformed the therapeutic approach in chronic lymphocytic leukemia (CLL). Despite these advancements, the disease continues to be characterized by immune dysfunction and increased susceptibility to infections, with mortality rates from infections showing no significant improvement over the past few decades. Therefore, timely prevention, recognition, and treatment of infections remains an important aspect of the standard management of a patient with CLL. A panel of hematologists with expertise in CLL met to discuss existing literature and clinical insights for the management of infectious in CLL undergoing ibrutinib treatment. Despite not being a fully comprehensive review on the topic, this work provides a set of practical recommendations that can serve as a guide to healthcare professionals who manage these patients in their daily clinical practice.

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 further adjustment 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.

Real-World Treatment Patterns and Outcomes by Line of Therapy and Race in Patients With Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma Treated in the United States: Results From the Final Analysis of the Prospective, Observational, informCLL Registry

BACKGROUND

informCLL is the largest US-based prospective, observational registry of patients with chronic lymphocytic leukemia (CLL) initiating FDA-approved treatment in the era of targeted therapy.

PATIENTS AND METHODS

Patients were enrolled between October 2015 and June 2019. Data were collected for baseline characteristics, treatment patterns, outcomes, and safety.

RESULTS

In total, 1459 eligible patients were enrolled (first line, n = 854; relapsed/refractory, n = 605). The most common index treatments were ibrutinib (first line, 45%; relapsed/refractory, 49%) and chemoimmunotherapy (first line, 43%; relapsed/refractory, 20%). With median follow-up of 31.8 and 30.9 months in first-line and relapsed/refractory cohorts, respectively, median time to next treatment (TTNT) in patients who received any index treatment was not reached (NR) and 48.6 months; estimated proportions without next-line therapy at 48 months were 64% and 50%. Median overall survival (OS) was NR for both cohorts; estimated 48-month OS rates were 81% and 64% in first-line and relapsed/refractory cohorts, respectively. In match-adjusted analyses, TTNT was improved with first-line ibrutinib versus chemoimmunotherapy (median NR vs. 56.5 months; hazard ratio, 0.74; 95% CI, 0.56-0.98). Exposure-adjusted rates of AEs leading to discontinuation and serious AEs were lower with ibrutinib versus chemoimmunotherapy. Estimated 36-month OS rates were similar in Black versus White patients who received any index treatment (first line, 87% vs. 83%; relapsed/refractory, 74% vs. 74%) or ibrutinib (first line, 97% vs. 85%; relapsed/refractory, 81% vs. 77%).

CONCLUSION

In this prospective, large, real-world CLL registry, first-line ibrutinib was associated with longer TTNT than chemoimmunotherapy, with sustained benefit up to 4 years of follow-up.

Safety profile of first-line targeted therapies in elderly and/or comorbid chronic lymphocytic leukaemia patients (unfit subpopulation). A systematic review and network meta-analysis

This systematic literature review (CRD42023393903) and a Bayesian network meta-analysis (NMA) aimed to assess the relative safety profile of first-line targeted therapies (acalabrutinib, ibrutinib, obinutuzumab, ofatumumab, pirtobrutinib, ublituximab, umbralisib, venetoclax, zanubrutinib) in chronic lymphocytic leukaemia (CLL) patients with advanced age and/or comorbidities. The NMA revealed that zanubrutinib was the safest treatment option in terms of the overall safety profile (e.g., serious adverse events [AEs] grade 1-5), followed by venetoclax-obinutuzumab, which showed an advantage in terms of AEs grade 1-5. The use of Bruton's tyrosine kinase inhibitor (BTKi) monotherapy was more favourable in terms of the risk of haematological AEs, but chemoimmunotherapy showed advantages in terms of cardiovascular, gastrointestinal, and infectious AEs. The risk of secondary cancers was similar between treatments. In conclusion, targeted therapies are associated with variable and clinically relevant AEs. The therapies appear to be safer when used as monotherapy rather than in combination with immunological agents in naïve CLL patients with advanced age and/or comorbidities.

Bruton tyrosine kinase inhibitor monotherapy in B-cell lymphoma and risk of infection: A systematic review and meta-analysis of randomized controlled trials

Bruton's tyrosine kinase (BTK) inhibitors are important therapeutic advances with promising efficacy outcomes in the treatment of patients with chronic lymphocytic leukemia and other B-cell lymphoma subtypes. However, the utility of BTK inhibitors can be limited by adverse events such as infections. In this systematic review and meta-analysis, we aim to determine the risk of various infections associated with BTK inhibitor monotherapy in B-cell lymphoma patients. A comprehensive search was conducted in MEDLINE/PubMed, Embase, and Web of Science databases from their inception until October 2023. ClinicalTrials.gov, bibliographies, and relevant conference abstracts were also searched for additional records. Randomized controlled trials that included any B-cell lymphoma patients treated with BTK inhibitor monotherapy and reported infection were included. Meta-analysis was performed to calculate risk ratio (RR) using a random-effects model in R Statistical Software, version 4.3.2. Of 3292 studies retrieved, we included 12 studies in this systematic review and meta-analysis. The median age of patients across the study arms ranged between 64 and 73 years. The overall pooled RR for any grade upper respiratory tract infections (URTI) associated with BTK inhibitor treatment was 1.55 (95% Confidence Interval (CI) 1.22-1.97). The RR of grade ≥3 URTI was reported in 14 out of 1046 patients, yielding an RR of 1.46 (95% CI 0.61-3.54), which was not statistically significant. The pooled RR of any grade pneumonia was 1.20 (95% CI 0.68-2.10) and grade ≥3 pneumonia was 1.12 (95% CI 0.67-1.85), both of which were not statistically significant. Patients with B-cell lymphoma who are undergoing BTK inhibitor monotherapy face an elevated risk of developing URTI. Clinicians prescribing BTK inhibitors should be aware of the potential infectious events that may occur. Close monitoring and the implementation of effective prophylactic measures are essential for managing these patients.

Pharmacological management of chronic lymphocytic leukemia: current and emerging therapies

INTRODUCTION

Chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), characterized by its monoclonal lymphoproliferative nature, is an indolent but incurable malignancy. The treatment landscape of CLL/SLL has drastically transformed in the last decade since the introduction of targeted therapy and immune-effector T-cell therapy. The paradigm shift from chemoimmunotherapy to targeted and cellular therapies was largely driven by improved efficacy and safety. With the success of targeted therapies, novel agents and combinations are rapidly emerging on the horizon.

AREAS COVERED

In this review, we will summarize clinical evidence supporting current and emerging therapies with emphasis on investigational therapies and novel combinations of commercial agents. Clinical trials were identified via clinicaltrials.gov, and a PubMed literature search was last performed in June 2024.

EXPERT OPINION

With the availability of more effective and better-tolerated treatments for CLL/SLL, the role of early intervention should be further investigated due to its potential to alter disease course, delay progression, and improve overall survival rates. With many highly effective agents and combinations expected to become commercially available, attention to safety profiles and careful selection of patients for each treatment will be critical, with consideration of comorbidities, logistical issues, and financial burden of treatment.

Severe infections in patients with chronic lymphocytic leukemia included in trials investigating BTK and BCL2 inhibitors

Bruton tyrosine kinase inhibitors (BTKi) and the BCL-2 inhibitor venetoclax have significantly improved the prognosis of patients with chronic lymphocytic leukemia (CLL). However, the incidence of severe infections in patients receiving these agents needs to be better understood. Our review aimed to provide an overview of grade ≥3 infections in patients with CLL who received BTKi and venetoclax-based therapy in prospective trials. Infection rates were influenced by the age of patients and the duration of follow-up. For treatment-naive (TN) patients receiving BTKi, infection rates ranged between 11.4 % and 27.4 % and were close to 30 % in relapsed/refractory (R/R) patients. TN and R/R patients receiving fixed-duration venetoclax-based treatments showed variable rates, with maximum values around 20 %. Opportunistic and fatal infections were uncommon. In conclusion, infections remain a concern in patients with CLL receiving targeted agents. A better definition of factors increasing infection vulnerability could help identify those patients who require infection prophylaxis.

Targeting chronic lymphocytic leukemia with B-cell activating factor receptor CAR T cells

The challenge of disease relapsed/refractory (R/R) remains a therapeutic hurdle in chimeric antigen receptor (CAR) T-cell therapy, especially for hematological diseases, with chronic lymphocytic leukemia (CLL) being particularly resistant to CD19 CAR T cells. Currently, there is no approved CAR T-cell therapy for CLL patients. In this study, we aimed to address this unmet medical need by choosing the B-cell activating factor receptor (BAFF-R) as a promising target for CAR design against CLL. BAFF-R is essential for B-cell survival and is consistently expressed on CLL tumors. Our research discovered that BAFF-R CAR T-cell therapy exerted the cytotoxic effects on both CLL cell lines and primary B cells derived from CLL patients. In addition, the CAR T cells exhibited cytotoxicity against CD19-knockout CLL cells that are resistant to CD19 CAR T therapy. Furthermore, we were able to generate BAFF-R CAR T cells from small blood samples collected from CLL patients and then demonstrated the cytotoxic effects of these patient-derived CAR T cells against autologous tumor cells. Given these promising results, BAFF-R CAR T-cell therapy has the potential to meet the long-standing need for an effective treatment on CLL patients.

Measurable Residual Disease and Clinical Outcomes in Chronic Lymphocytic Leukemia: A Systematic Review and Meta-Analysis

Importance

Measurable residual disease (MRD) refers to the presence of disease at low levels not detected by conventional pathologic analysis. The association of MRD status as a surrogate end point of clinical outcome in chronic lymphocytic leukemia (CLL) has not been established in the era of targeted agents. Assessing the association of MRD with progression-free survival (PFS) may improve its role as a surrogate marker and allow its use to accelerate drug development.

Objective

To assess the association between MRD and PFS in CLL using data from prospective clinical trials that studied targeted agents or obinutuzumab-based treatment.

Data Sources

Clinical studies on CLL were identified via searches of PubMed, Embase, Scopus, and Web of Science from inception through July 31, 2023.

Study Selection

Prospective, single-arm, and randomized clinical trials that assessed targeted agents or obinutuzumab-based treatment and reported PFS by MRD status were included. Studies with insufficient description of MRD information were excluded.

Data Extraction and Synthesis

Study sample size, median patient age, median follow-up time, line of treatment, MRD detection method and time points, and survival outcomes were extracted.

Main Outcomes and Measures

Analyses of survival probabilities and hazard ratios (HRs) were conducted for PFS according to MRD status. Meta-analyses were performed using a random-effects model.

Results

A total of 11 prospective clinical trials (9 randomized and 2 nonrandomized) including 2765 patients were analyzed. Achieving undetectable MRD (uMRD) at 0.01% was associated with an HR of 0.28 (95% CI, 0.20-0.39; P < .001) for PFS. Median PFS was not reached in both groups (uMRD vs MRD), but the estimated 24-month PFS was better in the uMRD group (91.9% [95% CI, 88.8%-95.2%] vs 75.3% [95% CI, 64.7%-87.6%]; P < .001). The association of uMRD with PFS was observed in subgroup analyses in the first-line treatment setting (HR, 0.24; 95% CI, 0.18-0.33), relapsed or refractory disease setting (HR, 0.34; 95% CI, 0.16-0.71), and trials using time-limited therapy (HR, 0.28; 95% CI, 0.19-0.40).

Conclusions and Relevance

The findings of this systematic review and meta-analysis suggest that assessing MRD status as an end point in clinical trials and as a surrogate of PFS may improve trial efficiency and potentially allow for accelerated drug registration.

Targeted protein degradation in hematologic malignancies: clinical progression towards novel therapeutics

Targeted therapies, such as small molecule kinase inhibitors, have made significant progress in the treatment of hematologic malignancies by directly modulating protein activity. However, issues such as drug toxicity, drug resistance due to target mutations, and the absence of key active sites limit the therapeutic efficacy of these drugs. Targeted protein degradation (TPD) presents an emergent and rapidly evolving therapeutic approach that selectively targets proteins of interest (POI) based on endogenous degradation processes. With an event-driven pharmacology of action, TPD achieves efficacy with catalytic amounts, avoiding drug-related toxicity. Furthermore, TPD has the unique mode of degrading the entire POI, such that resistance derived from mutations in the targeted protein has less impact on its degradation function. Proteolysis-targeting chimeras (PROTACs) and molecular glue degraders (MGDs) are the most maturely developed TPD techniques. In this review, we focus on both preclinical experiments and clinical trials to provide a comprehensive summary of the safety and clinical effectiveness of PROTACs and MGDs in hematologic malignancies over the past two decades. In addition, we also delineate the challenges and opportunities associated with these burgeoning degradation techniques. TPD, as an approach to the precise degradation of specific proteins, provides an important impetus for its future application in the treatment of patients with hematologic malignancies.

Chronic lymphocytic leukaemia

The last decade has seen remarkable progress in our understanding of disease biology of chronic lymphocytic leukaemia (CLL) and the development of novel targeted therapies. Randomised clinical trials have reported improved progression-free survival and overall survival with targeted therapies compared with chemoimmunotherapy, and thereby the role of chemoimmunotherapy in todays' era for treatment of CLL is limited. Bruton tyrosine kinase (BTK) inhibitors, BCL2 inhibitors, and CD20 monoclonal antibodies have been established as appropriate therapy options for patients with CLL, both as the first-line treatment and in the treatment of relapsed or refractory CLL. Several ongoing phase 3 trials are exploring different combinations of targeted therapies, and the results of these trials might change the treatment framework in first-line treatment of CLL. Non-covalent BTK inhibitors, chimeric antigen receptor T-cell therapy, and other therapeutic strategies are being investigated in relapsed CLL. Some of the therapies used in relapsed CLL, such as non-covalent BTK inhibitors, are now being pursued in earlier lines of therapy, including first-line treatment of CLL.

Overall survival of patients with CLL treated with ibrutinib in the first line compared to second-line ibrutinib after chemotherapy/chemoimmunotherapy

OBJECTIVE

To evaluate the overall survival (OS) of patients with chronic lymphocytic leukemia (CLL) receiving either ibrutinib monotherapy as a first-line (1L) treatment or chemotherapy/chemoimmunotherapy-based (CT/CIT) regimens in 1L followed by ibrutinib in the second line (1L CT/CIT-2L ibrutinib) after disease progression by emulating a randomized trial comparing both treatment sequences.

METHODS

Patient-level data from the RESONATE-2 trial (NCT01722487) and real-world PHEDRA databases were analyzed. Three scenarios were considered using the following data sources: (1) RESONATE-2, (2) combined RESONATE-2/PHEDRA, (3) combined RESONATE-2/PHEDRA for 1L ibrutinib and PHEDRA for 1L CT/CIT-2L ibrutinib. Propensity score-based weights and inverse probability of censoring weighting were used to adjust for baseline (Scenarios 2 and 3) and time-dependent confounding (all scenarios), and to address potential biases. A weighted Cox proportional hazards model was used to estimate the OS hazard ratio (HR) and 95% confidence interval (CI) for 1L ibrutinib versus 1L CT/CIT-2L ibrutinib.

RESULTS

Results from Scenario 1 showed a significantly lower risk of death with 1L ibrutinib compared with 1L chlorambucil followed by 2L ibrutinib (HR 0.35 [95% CI 0.20-0.62]). Results from Scenarios 2 and 3 demonstrated a reduced risk of death with 1L ibrutinib compared with 1L CT/CIT-2L ibrutinib (HR 0.35 [0.21-0.61] and 0.64 [0.39-1.04], respectively).

CONCLUSION

The analyses consistently showed a reduced risk of death when ibrutinib was used as a 1L treatment in CLL compared with delaying its use until 2L after CT/CIT regimens, which suggests that initiating ibrutinib in 1L is advantageous for improving survival outcomes.

Chronic Lymphocytic Leukemia in Pregnancy: A Review of the Available Literature and the Pharmacological Challenges in Management

BACKGROUND

Chronic lymphocytic leukemia (CLL) is a rare hematologic malignancy to occur in pregnancy, with an estimated incidence of 1 in 75,000 pregnancies. Pregnant women with CLL face increased susceptibility to infections, due to a weakened immune system. Higher risks of fetal malformations and death are associated with CLL treatment during pregnancy, emphasizing the need for careful consideration and management in these cases.

SUMMARY

This review aimed to summarize the current evidence regarding the diagnosis, prognosis, and treatment of CLL in pregnant cases. A comprehensive search strategy was employed across multiple databases, yielding 14 case reports for inclusion. The cases were divided based on CLL diagnosis onset, either before or during pregnancy. Our results showed that patients diagnosed during pregnancy (n = 5) were mostly asymptomatic at diagnosis, with management ranging from supportive care to leukapheresis and transfusions. Postpartum treatment varied, with some patients requiring no additional therapy and others receiving chemotherapy. Pregnancy outcomes were generally favorable, with most neonates born healthy at term. However, one case of Richter transformation resulted in maternal death despite treatment. Among patients with pre-existing CLL (n = 9), the majority experienced an indolent course during pregnancy, with only supportive care required. A few cases necessitated treatment due to progressive disease or complications, including chemotherapy, leukapheresis, and splenectomy.

KEY MESSAGES

This review highlights the heterogeneous nature of CLL in pregnancy and the importance of individualized management based on disease severity, gestational age, and maternal-fetal risks. Close monitoring, supportive care, and a multidisciplinary approach are essential for optimizing outcomes in this rare and complex clinical scenario.

Acalabrutinib, venetoclax, and obinutuzumab in relapsed/refractory CLL: final efficacy and ctDNA analysis of the CLL2-BAAG trial

ABSTRACT

The phase 2 CLL2-BAAG trial tested the measurable residual disease (MRD)-guided triple combination of acalabrutinib, venetoclax, and obinutuzumab after optional bendamustine debulking in 45 patients with relapsed/refractory chronic lymphocytic leukemia (CLL). MRD was measured by flow cytometry (FCM; undetectable MRD <10-4) in peripheral blood (PB) and circulating tumor DNA (ctDNA) using digital droplet polymerase chain reaction of variable-diversity-joining (VDJ) rearrangements and CLL-related mutations in plasma. The median number of previous treatments was 1 (range, 1-4); 18 patients (40%) had received a Bruton tyrosine kinase inhibitor (BTKi) and/or venetoclax before inclusion, 14 of 44 (31.8%) had TP53 aberrations, and 34 (75.6%) had unmutated immunoglobulin heavy-chain variable region genes. With a median observation time of 36.3 months and all patients off-treatment for a median of 21.9 months, uMRD <10-4 in PB was achieved in 42 of the 45 patients (93.3%) at any time point, including 17 of 18 (94.4%) previously exposed to venetoclax/BTKi and 13 of 14 (92.9%) with TP53 aberrations. The estimated 3-year progression-free and overall survival rates were 85.0% and 93.8%, respectively. Overall, 585 paired FCM/ctDNA samples were analyzed and 18 MRD recurrences (5 with and 13 without clinical progression) occurred after the end of treatment. Twelve samples were first detected by ctDNA, 3 by FCM, and 3 synchronously. In conclusion, time-limited MRD-guided acalabrutinib, venetoclax, and obinutuzumab achieved deep remissions in almost all patients with relapsed/refractory CLL. The addition of ctDNA-based analyses to FCM MRD assessment seems to improve early detection of relapses. This trial was registered at www.clinicaltrials.gov as #NCT03787264.

Real-world treatment patterns and outcomes for patients with CLL using the Australian pharmaceutical benefits scheme (PBS) dataset

This real-world retrospective cohort study using Australian Pharmaceutical Benefits Scheme (PBS) 10% investigated changes in chronic lymphocytic leukemia (CLL) treatment by line of therapy, time-to-next-treatment, treatment duration, and overall survival (OS). Overall, 803 patients received their first PBS-reimbursed CLL medication between 1 January 2011 to 31 July 2021 (median age: 70 years; 64.6% male), 289 post-1 August 2020. In 2011, most first-line (1 L) prescribing was fludarabine, cyclophosphamide, and rituximab (FCR). By 2021, common 1L were chlorambucil ± CD20 (26.1%), Bruton Tyrosine Kinase inhibitor (BTKi) (26.1%), and CD20 monotherapy (23.9%). In 2011, relapsed/refractory (R/R) CLL treatment was CD20 monotherapy or FCR. By 2021, BTKi (57.7%) and venetoclax ± CD20 (26.1%) were most common. Compared to FCR, 1 L treatment duration (Hazard Ratio) was shorter for CD20 monotherapy (1.7) or chlorambucil ± CD20 (2.5). In R/R CLL, median duration was 24 (ibrutinib) and 19 months (venetoclax). Median OS was 127 months. CLLtreatment pattern shave greatly changed in Australia since the introduction of novel therapies.

ERIC recommendations for TP53 mutation analysis in chronic lymphocytic leukemia-2024 update

In chronic lymphocytic leukemia (CLL), analysis of TP53 aberrations (deletion and/or mutation) is a crucial part of treatment decision-making algorithms. Technological and treatment advances have resulted in the need for an update of the last recommendations for TP53 analysis in CLL, published by ERIC, the European Research Initiative on CLL, in 2018. Based on the current knowledge of the relevance of low-burden TP53-mutated clones, a specific variant allele frequency (VAF) cut-off for reporting TP53 mutations is no longer recommended, but instead, the need for thorough method validation by the reporting laboratory is emphasized. The result of TP53 analyses should always be interpreted within the context of available laboratory and clinical information, treatment indication, and therapeutic options. Methodological aspects of introducing next-generation sequencing (NGS) in routine practice are discussed with a focus on reliable detection of low-burden clones. Furthermore, potential interpretation challenges are presented, and a simplified algorithm for the classification of TP53 variants in CLL is provided, representing a consensus based on previously published guidelines. Finally, the reporting requirements are highlighted, including a template for clinical reports of TP53 aberrations. These recommendations are intended to assist diagnosticians in the correct assessment of TP53 mutation status, but also physicians in the appropriate understanding of the lab reports, thus decreasing the risk of misinterpretation and incorrect management of patients in routine practice whilst also leading to improved stratification of patients with CLL in clinical trials.

Ibrutinib followed by ofatumumab consolidation in previously untreated patients with chronic lymphocytic leukemia (CLL): GELLC-7 trial from the Spanish group of CLL (GELLC)

Background

BTK inhibitors have been concurrently administered with anti-CD20 monoclonal antibodies (mAbs) in chronic lymphocytic leukemia (CLL). However, the optimal regimen for combining these two drugs remains pending.

Methods

This multi-center phase 2 study aimed to analyze whether consolidation with ofatumumab improved the response in patients with CLL receiving front-line treatment with ibrutinib. Patients received 12 cycles of ibrutinib monotherapy. Those who achieved CR after this induction were maintained on ibrutinib. Conversely, those who did not attain CR continued with ibrutinib in addition to a consolidation, which involved 7 doses of ofatumumab. The primary objective was the complete response (CR) rate at cycle 20. This study is registered within the EU Clinical Trials Register (EudraCT 2016-004937-26).

Findings

Between September 8, 2017, and May 21, 2018, 84 patients (median age, 69 years) were included. After completion of 12 cycles of ibrutinib (n = 80), 4 patients (5%) were in CR, 67 (84%) in partial response (PR), and 6 patients (7%) had a PR with lymphocytosis (PRL). After consolidation with ofatumumab, 20 patients improved the response from PR to CR and 6 patients with PRL obtained a PR. Seventy-one patients (85%) completed 20 cycles of treatment, with a CR rate of 24/71 (34%). According to the intention-to-treat analysis at cycle 20, the ORR was 69/84 (82.2%), with a CRR of 24/84 (28.6%). Progression-free survival and overall survival at 48-months were 89.9% (CI: 82.4-95.5) and 92.2% (CI: 85.3-97.1), respectively.

Interpretation

These findings underscore the potential for a consolidation strategy in CLL, wherein the addition of a mAb in patients with low tumor burden might enhance the quality of the response.

Funding

The study was funded by Janssen that also supplied ibrutinib, whereas ofatumumab was supplied by Novartis.

The prognostic significance of genomic complexity in patients with CLL

Chromosomal aberrations are a common feature of cancer and can fuel cancer progression and treatment resistance. In chronic lymphocytic leukemia (CLL), the presence of multiple chromosomal aberrations is commonly referred to as "genomic complexity" or "complex karyotype"- (CKT). In the context of chemo- and chemoimmunotherapy, genomic complexity is associated with poor response to treatment and short survival, while some targeted therapies are able to mitigate its adverse prognostic impact. This article reviews currently available data and literature on the role of genomic complexity in CLL. The currently established tools to measure genomic complexity in patients with CLL are summarized and their strengths and weaknesses for routine diagnostics are evaluated. Moreover, possible definitions of CKT as an indicator for genomic complexity are discussed. Finally, data on the impact of CKT on clinical outcomes of patients with CLL are reviewed and the implications for patient stratification are presented.

Reassessing the chronic lymphocytic leukemia International Prognostic Index in the era of targeted therapies

ABSTRACT

We evaluated the chronic lymphocytic leukemia International Prognostic Index (CLL-IPI) in patients with CLL treated first line with targeted drugs (n = 991) or chemoimmunotherapy (n = 1256). With a median observation time of 40.5 months, the 3-year progression-free survival (PFS) rates for targeted drug-treated patients varied by CLL-IPI risk group: 96.5% (low), 87.6% (intermediate), 82.4% (high), and 78.7% (very high). Differences between consecutive CLL-IPI risk groups were observed for intermediate vs low and high vs intermediate, but not very high vs high. CLL-IPI factors β2-microglobulin, immunoglobulin heavy variable (IGHV) status, and TP53 status each retained prognostic value for PFS. The 3-year overall survival (OS) rates by CLL-IPI risk groups were 100%, 96%, 93.9%, and 89.4%, respectively, with no differences between consecutive risk groups. Age, Binet stage, β2-microglobulin, and TP53 status each retained prognostic value for OS. In chemoimmunotherapy patients (median observation time, 66.9 months), 3-year PFS rates for CLL-IPI risk groups were 78.1%, 51.4%, 40.1%, and 16.5%, respectively; corresponding 3-year OS rates were 97.4%, 93.1%, 81.8%, and 57.3%. In a matched-pair analysis, PFS differences in targeted therapies (n = 812) vs chemoimmunotherapy (n = 812) across all risk groups and OS differences in all but patients at low risk were demonstrated. The CLL-IPI maintains its prognostic value in predicting PFS outcomes with targeted drugs, but its impact in predicting survival appears diminished. Targeted therapies showed enhanced outcomes over chemoimmunotherapy, highlighting their effectiveness across various risk groups. Our findings support ongoing assessment of prognostic tools in CLL treatment evolution. These trials were registered at www.ClinicalTrials.gov as #NCT02345863, #NCT02401503, #NCT02689141, #NCT02445131, #NCT02758665, #NCT02950051, #NCT02242942, #NCT00262782, #NCT00281918, and #NCT01010061.

Impaired Cardiac AMPK (5'-Adenosine Monophosphate-Activated Protein Kinase) and Ca2+-Handling, and Action Potential Duration Heterogeneity in Ibrutinib-Induced Ventricular Arrhythmia Vulnerability

BACKGROUND

We recently demonstrated that acute administration of ibrutinib, a Bruton's tyrosine kinase inhibitor used in chemotherapy for blood malignancies, increases ventricular arrhythmia (VA) vulnerability. A pathway of ibrutinib-induced vulnerability to VA that can be modulated for cardioprotection remains unclear.

METHODS AND RESULTS

The effects of ibrutinib on cardiac electrical activity and Ca2+ dynamics were investigated in Langendorff-perfused hearts using optical mapping. We also conducted Western blotting analysis to evaluate the impact of ibrutinib on various regulatory and Ca2+-handling proteins in rat cardiac tissues. Treatment with ibrutinib (10 mg/kg per day) for 4 weeks was associated with an increased VA inducibility (72.2%±6.3% versus 38.9±7.0% in controls, P<0.002) and shorter action potential durations during pacing at various frequencies (P<0.05). Ibrutinib also decreased heart rate thresholds for beat-to-beat duration alternans of the cardiac action potential (P<0.05). Significant changes in myocardial Ca2+ transients included lower amplitude alternans ratios (P<0.05), longer times-to-peak (P<0.05), and greater spontaneous intracellular Ca2+ elevations (P<0.01). We also found lower abundance and phosphorylation of myocardial AMPK (5'-adenosine monophosphate-activated protein kinase), indicating reduced AMPK activity in hearts after ibrutinib treatment. An acute treatment with the AMPK activator 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside ameliorated abnormalities in action potential and Ca2+ dynamics, and significantly reduced VA inducibility (37.1%±13.4% versus 72.2%±6.3% in the absence of 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, P<0.05) in hearts from ibrutinib-treated rats.

CONCLUSIONS

VA vulnerability inflicted by ibrutinib may be mediated in part by an impairment of myocardial AMPK activity. Pharmacological activation of AMPK may be a protective strategy against ibrutinib-induced cardiotoxicity.

An indirect comparison of acalabrutinib with and without obinutuzumab vs zanubrutinib in treatment-naive CLL

ABSTRACT

The efficacy and safety of acalabrutinib plus obinutuzumab and acalabrutinib monotherapy vs zanubrutinib in patients with treatment-naive chronic lymphocytic leukemia/small lymphocytic lymphoma without del(17p) were compared using an unanchored matching-adjusted indirect comparison. Individual patient-level data from ELEVATE-TN (acalabrutinib plus obinutuzumab, n = 162; acalabrutinib monotherapy, n = 163) were weighted to match published aggregate baseline data from SEQUOIA cohort 1, which excluded patients with del(17p) (zanubrutinib, n = 241), using variables that were prognostic/predictive of investigator-assessed progression-free survival (INV-PFS) in an exploratory Cox regression analysis of ELEVATE-TN. After matching, INV-PFS was longer with acalabrutinib plus obinutuzumab (hazard ratio [HR], 0.41; 95% confidence interval [CI], 0.23-0.74) and comparable with acalabrutinib monotherapy (HR, 0.91; 95% CI, 0.53-1.56) vs zanubrutinib. Acalabrutinib monotherapy had significantly lower odds of any grade hypertension vs zanubrutinib (odds ratio [OR], 0.44; 95% CI, 0.20-0.99), whereas acalabrutinib plus obinutuzumab had significantly higher odds of neutropenia (OR, 2.19; 95% CI, 1.33-3.60) and arthralgia (OR, 2.33; 95% CI, 1.37-3.96) vs zanubrutinib. No other significant differences in safety were observed. In summary, acalabrutinib plus obinutuzumab had longer INV-PFS with increased odds of neutropenia and arthralgia than zanubrutinib, whereas acalabrutinib monotherapy had similar INV-PFS with lower odds of any grade hypertension. These trials were registered at www.ClinicalTrials.gov as #NCT02475681 and #NCT03336333.

Patient-Reported Outcomes in Phase 3 Clinical Trials for Blood Cancers: A Systematic Review

Importance

Published research suggests that patient-reported outcomes (PROs) are neither commonly collected nor reported in randomized clinical trials (RCTs) for solid tumors. Little is known about these practices in RCTs for hematological malignant neoplasms.

Objective

To evaluate the prevalence of PROs as prespecified end points in RCTs of hematological malignant neoplasms, and to assess reporting of PROs in associated trial publications.

Evidence Review

All issues of 8 journals known for publishing high-impact RCTs (NEJM, Lancet, Lancet Hematology, Lancet Oncology, Journal of Clinical Oncology, Blood, JAMA, and JAMA Oncology) between January 1, 2018, and December 13, 2022, were searched for primary publications of therapeutic phase 3 trials for adults with hematological malignant neoplasms. Studies that evaluated pretransplant conditioning regimens, graft-vs-host disease treatment, or radiotherapy as experimental treatment were excluded. Data regarding trial characteristics and PROs were extracted from manuscripts and trial protocols. Univariable analyses assessed associations between trial characteristics and PRO collection or reporting.

Findings

Ninety RCTs were eligible for analysis. PROs were an end point in 66 (73%) trials: in 1 trial (1%) as a primary end point, in 50 (56%) as a secondary end point, and in 15 (17%) as an exploratory end point. PRO data were reported in 26 of 66 primary publications (39%): outcomes were unchanged in 18 and improved in 8, with none reporting worse PROs with experimental treatment. Trials sponsored by for-profit entities were more likely to include PROs as an end point (49 of 55 [89%] vs 17 of 35 [49%]; P < .001) but were not significantly more likely to report PRO data (20 of 49 [41%] vs 6 of 17 [35%]; P = .69). Compared with trials involving lymphoma (18 of 29 [62%]) or leukemia or myelodysplastic syndrome (18 of 28 [64%]), those involving plasma cell disorders or multiple myeloma (27 of 30 [90%]) or myeloproliferative neoplasms (3 of 3 [100%]) were more likely to include PROs as an end point (P = .03). Similarly, compared with trials involving lymphoma (3 of 18 [17%]) or leukemia or myelodysplastic syndrome (5 of 18 [28%]), those involving plasma cell disorders or multiple myeloma (16 of 27 [59%]) or myeloproliferative neoplasms (2 of 3 [67%]) were more likely to report PROs in the primary publication (P = .01).

Conclusions and Relevance

In this systematic review, almost 3 of every 4 therapeutic RCTs for blood cancers collected PRO data; however, only 1 RCT included PROs as a primary end point. Moreover, most did not report resulting PRO data in the primary publication and when reported, PROs were either better or unchanged, raising concern for publication bias. This analysis suggests a critical gap in dissemination of data on the lived experiences of patients enrolled in RCTs for hematological malignant neoplasms.

First-line venetoclax combinations versus chemoimmunotherapy in fit patients with chronic lymphocytic leukaemia (GAIA/CLL13): 4-year follow-up from a multicentre, open-label, randomised, phase 3 trial

BACKGROUND

In the primary analysis report of the GAIA/CLL13 trial, we found that venetoclax-obinutuzumab and venetoclax-obinutuzumab-ibrutinib improved undetectable measurable residual disease (MRD) rates and progression-free survival compared with chemoimmunotherapy in patients with previously untreated chronic lymphocytic leukaemia. However, to our knowledge, no data on direct comparisons of different venetoclax-based combinations are available.

METHODS

GAIA/CLL13 is an open-label, randomised, phase 3 study conducted at 159 sites in ten countries in Europe and the Middle East. Eligible patients were aged 18 years or older, with a life expectancy of at least 6 months, an Eastern Cooperative Oncology group performance status of 0-2, a cumulative illness rating scale score of 6 or lower or a single score of 4 or lower, and no TP53 aberrations. Patients were randomly assigned (1:1:1:1), with a computer-generated list stratified by age, Binet stage, and regional study group, to either chemoimmunotherapy, venetoclax-rituximab, venetoclax-obinutuzumab, or venetoclax-obinutuzumab-ibrutinib. All treatments were administered in 28-day cycles. Patients in the chemoimmunotherapy group received six cycles of treatment, with patients older than 65 years receiving intravenous bendamustine (90 mg/m2, days 1-2), whereas patients aged 65 years or younger received intravenous fludarabine (25 mg/m2, days 1-3) and intravenous cyclophosphamide (250 mg/m2, days 1-3). Intravenous rituximab (375 mg/m2, day 1 of cycle 1; 500 mg/m2, day 1 of cycles 2-6) was added to chemotherapy. In the experimental groups, patients received daily venetoclax (400 mg orally) for ten cycles after a 5-week ramp-up phase starting on day 22 of cycle 1. In the venetoclax-rituximab group, intravenous rituximab (375 mg/m2, day 1 of cycle 1; 500 mg/m2, day 1 of cycles 2-6) was added. In the obinutuzumab-containing groups, obinutuzumab was added (cycle 1: 100 mg on day 1, 900 mg on day 2, and 1000 mg on days 8 and 15; cycles 2-6: 1000 mg on day 1). In the venetoclax-obinutuzumab-ibrutinib group, daily ibrutinib (420 mg orally, from day 1 of cycle 1) was added until undetectable MRD was reached in two consecutive measurements (3 months apart) or until cycle 36. The planned treatment duration was six cycles in the chemoimmunotherapy group, 12 cycles in the venetoclax-rituximab and the venetoclax-obinutuzumab group and between 12 and 36 cycles in the venetoclax-obinutuzumab-ibrutinib group. Coprimary endpoints were the undetectable MRD rate in peripheral blood at month 15 for the comparison of venetoclax-obinutuzumab versus standard chemoimmunotherapy and investigator-assessed progression-free survival for the comparison of venetoclax-obinutuzumab-ibrutinib versus standard chemoimmunotherapy, both analysed in the intention-to-treat population (ie, all patients randomly assigned to treatment) with a split α of 0·025 for each coprimary endpoint. Both coprimary endpoints have been reported elsewhere. Here we report a post-hoc exploratory analysis of updated progression-free survival results after a 4-year follow-up of our study population. Safety analyses included all patients who received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, NCT02950051, recruitment is complete, and all patients are off study treatment.

FINDINGS

Between Dec 13, 2016, and Oct 13, 2019, 1080 patients were screened and 926 were randomly assigned to treatment (chemoimmunotherapy group n=229; venetoclax-rituximab group n=237; venetoclax-obinutuzumab group n=229; and venetoclax-obinutuzumab-ibrutinib group n=231); mean age 60·8 years (SD 10·2), 259 (28%) of 926 patients were female, and 667 (72%) were male (data on race and ethnicity are not reported). At data cutoff for this exploratory follow-up analysis (Jan 31, 2023; median follow-up 50·7 months [IQR 44·6-57·9]), patients in the venetoclax-obinutuzumab group had significantly longer progression-free survival than those in the chemoimmunotherapy group (hazard ratio [HR] 0·47 [97·5% CI 0·32-0·69], p<0·0001) and the venetoclax-rituximab group (0·57 [0·38-0·84], p=0·0011). The venetoclax-obinutuzumab-ibrutinib group also had a significantly longer progression-free survival than the chemoimmunotherapy group (0·30 [0·19-0·47]; p<0·0001) and the venetoclax-rituximab group (0·38 [0·24-0·59]; p<0·0001). There was no difference in progression-free survival between the venetoclax-obinutuzumab-ibrutinib and venetoclax-obinutuzumab groups (0·63 [0·39-1·02]; p=0·031), and the proportional hazards assumption was not met for the comparison between the venetoclax-rituximab group versus the chemoimmunotherapy group (log-rank p=0·10). The estimated 4-year progression-free survival rate was 85·5% (97·5% CI 79·9-91·1; 37 [16%] events) in the venetoclax-obinutuzumab-ibrutinib group, 81·8% (75·8-87·8; 55 [24%] events) in the venetoclax-obinutuzumab group, 70·1% (63·0-77·3; 84 [35%] events) in the venetoclax-rituximab group, and 62·0% (54·4-69·7; 90 [39%] events) in the chemoimmunotherapy group. The most common grade 3 or worse treatment-related adverse event was neutropenia (114 [53%] of 216 patients in the chemoimmunotherapy group, 109 [46%] of 237 in the venetoclax-rituximab group, 127 [56%] of 228 in the venetoclax-obinutuzumab group, and 112 [48%] of 231 in the venetoclax-obinutuzumab-ibrutinib group). Deaths determined to be associated with study treatment by the investigator occurred in three (1%) patients in the chemoimmunotherapy group (n=1 due to each of sepsis, metastatic squamous cell carcinoma, and Richter's syndrome), none in the venetoclax-rituximab and venetoclax-obinutuzumab groups, and four (2%) in the venetoclax-obinutuzumab-ibrutinib group (n=1 due to each of acute myeloid leukaemia, fungal encephalitis, small-cell lung cancer, and toxic leukoencephalopathy).

INTERPRETATION

With more than 4 years of follow-up, venetoclax-obinutuzumab and venetoclax-obinutuzumab-ibrutinib significantly extended progression-free survival compared with both chemoimmunotherapy and venetoclax-rituximab in previously untreated, fit patients with chronic lymphocytic leukaemia, thereby supporting their use and further evaluation in this patient group, while still considering the higher toxicities observed with the triple combination.

FUNDING

AbbVie, Janssen, and F Hoffmann-La Roche.

Covalent Bruton's Tyrosine Kinase Inhibitors in Chronic Lymphocytic Leukemia

Inhibitors of Bruton's tyrosine kinase (BTK) are among the most widely used therapies for chronic lymphocytic leukemia (CLL) and established a new expectation for efficacy and safety in the treatment of this disease. Currently there are 3 covalent inhibitors of BTK approved for the treatment of CLL: ibrutinib, acalabrutinib, and zanubrutinib. The first-in-class covalent BTK inhibitor is ibrutinib, which as monotherapy has excellent efficacy in the front-line setting with a 7-year progression free survival (PFS) of 59%. Ibrutinib-based therapies have also demonstrated superiority over standard chemoimmunotherapy in the front-line and the relapsed/refractory setting. Acalabrutinib is a second-generation BTK inhibitor that has higher selectivity to BTK. Acalabrutinib has efficacy in both frontline and relapsed CLL and is associated with a decreased incidence of atrial fibrillation and hypertension when compared to ibrutinib. Like acalabrutinib, zanubrutinib was designed to be more selective for BTK than ibrutinib and to maximize BTK inhibition in tissues. Zanubrutinib has demonstrated clinical efficacy in first line and relapsed/refractory setting. These agents are indicated as monotherapy, with dosing until disease progression or intolerable toxicity, and are mainly differentiated by safety profile, although efficacy differences may exist as well. Combination with CD20 monoclonal antibodies and/or BCL2 inhibitors are alternative options for use. Here we will review efficacy and safety considerations with these agents.

Cardiovascular events reported in patients with B-cell malignancies treated with zanubrutinib

ABSTRACT

First-generation Bruton tyrosine kinase (BTK) inhibitor, ibrutinib, has been associated with an increased risk of cardiovascular toxicities. Zanubrutinib is a more selective, next-generation BTK inhibitor. In this analysis, incidence rates of atrial fibrillation, symptomatic (grade ≥2) ventricular arrhythmia, and hypertension were evaluated in a pooled analysis of 10 clinical studies with zanubrutinib monotherapy in patients (N = 1550) with B-cell malignancies and a pooled analysis of head-to-head studies comparing zanubrutinib with ibrutinib (ASPEN cohort 1; ALPINE). Among the 10 studies, most patients (median age, 67 years) were male (66.3%) and had CLL/SLL (60.5%). Overall incidence and exposure-adjusted incidence rates (EAIR) for atrial fibrillation, symptomatic ventricular arrhythmia, and hypertension were lower with zanubrutinib than ibrutinib. Despite a similar prevalence of preexisting cardiovascular events in ASPEN and ALPINE, atrial fibrillation/flutter incidence rates (6.1% vs 15.6%) and EAIR (0.2 vs 0.64 persons per 100 person-months; P < .0001) were lower with zanubrutinib than with ibrutinib. Symptomatic ventricular arrhythmia incidence was low for both zanubrutinib (0.7%) and ibrutinib (1.7%) with numerically lower EAIR (0.02 vs 0.06 persons per 100 person-months, respectively) for zanubrutinib. The hypertension EAIR was lower with zanubrutinib than ibrutinib in ASPEN but similar between treatment arms in ALPINE. The higher hypertension EAIR in ALPINE was inconsistent with other zanubrutinib studies. However, fewer discontinuations (1 vs 14) and deaths (0 vs 6) due to cardiac disorders occurred with zanubrutinib versus ibrutinib in ALPINE. These data support zanubrutinib as a treatment option with improved cardiovascular tolerability compared with ibrutinib for patients with B-cell malignancies in need of BTK inhibitors. These trials were registered at www.ClinicalTrials.gov as # NCT03053440, NCT03336333, NCT03734016, NCT04170283, NCT03206918, NCT03206970, NCT03332173, NCT03846427, NCT02343120, and NCT03189524.

Treatment Sequencing in Chronic Lymphocytic Leukemia in 2024: Where We Are and Where We Are Headed

As treatments with BTK inhibitors and BCL2 inhibitors have replaced the use of chemoimmunotherapy in CLL in both first-line and relapsed patients, it becomes critical to rationalize their use and exploit the full potential of each drug. Despite their proven, robust, and manifest efficacy, BTKis and BCL2is fail to provide long-term disease control in some categories of patients, and to date this is an unmet clinical need that is critical to recognize and address. Ongoing clinical trials are evaluating new treatment algorithms and new molecules to progressively thin this population. In this review for each category of patients we explicate the different possible patterns of treatment sequencing based on currently available evidence, starting from the frontline to currently ongoing trials, in order to optimize therapies as much as possible.

The impact of Bruton's tyrosine kinase inhibitor treatment on COVID-19 outcomes in Chinese patients with chronic lymphocytic leukemia

Background

Impact of B-cell depletion following treatment with Bruton tyrosine kinase-inhibitors (BTKi) on the outcome of SARS-CoV-2 infection in chronic lymphocytic leukemia (CLL) patients remain controversial. We investigated the impact of BTKi on susceptibility and the severity of COVID-19 in Chinese patients with CLL during the first wave of COVID-19 (Omicron variant).

Methods

CLL patients (n=171) visiting the Institute of Hematology, Peoples' Hospital, China (November 15, 2022- January 20, 2023) were included in the study. Seventeen patients receiving BTKi and venetoclax with or without obinutuzumab were excluded. Data from 117 patients receiving treatment with BTKi were collected using a standardized questionnaire through telephone interviews. Thirty-four patients without CLL-specific treatment served as controls. The data was analysed using IBM SPSS Software version 21 and a P value of <0.05 was considered statistically significant.

Results

The median age of patients was 67 years and majority were males (n=100). Treatment with BTKi was not associated with higher incidence of COVID-19 (74% [95% Confidence Interval (CI) 60%, 92%]) versus 74% (CI 48%, 100%) without any treatment (P=0.92). Hypoxemia was reported by 45% (32%, 61%) and 16% (4%, 41%) (P=0.01). BTKi was the only independent risk factor of hypoxemia (Hazard Ratio [HR], 4.22 [1.32, 13.50]; P = 0.02). Five (5.7%) patients with COVID-19 under BTKi required ICU admission; 4 of them died. No ICU admissions/deaths were observed in the control group.

Conclusion

In Chinese patients with CLL and treated with BTKi experienced more severe lung disease and ICU admissions due to COVID-19 than patients without CLL therapy. Frequency of infections with SARS-CoV-2, however, was not different in patients with or without BTKi treatment.

Hypertension treatment for patients receiving ibrutinib: a multicenter retrospective study

ABSTRACT

Although Bruton tyrosine kinase inhibitors (BTKis) are generally well tolerated and less toxic than chemotherapy alternatives used to treat lymphoid malignancies, BTKis like ibrutinib have the potential to cause new or worsening hypertension (HTN). Little is known about the optimal treatment of BTKi-associated HTN. Randomly selected patients with lymphoid malignancies on a BTKi and antihypertensive drug(s) and with at least 3 months of follow-up data were sorted into 2 groups: those diagnosed with HTN before BTKi initiation (prior-HTN), and those diagnosed with HTN after BTKi initiation (de novo HTN). Generalized estimating equations assessed associations between time varying mean arterial pressures (MAPs) and individual anti-HTN drug categories. Of 196 patients included in the study, 118 had prior-HTN, and 78 developed de novo HTN. Statistically significant mean MAP reductions were observed in patients with prior-HTN who took β blockers (BBs) with hydrochlorothiazide (HCTZ), (-5.05 mmHg; 95% confidence interval [CI], 10.0 to -0.0596; P = .047), and patients diagnosed with de novo HTN who took either an angiotensin converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) with HCTZ (-5.47 mmHg; 95% CI, 10.9 to -0.001; P = .05). These regimens also correlated with the greatest percentages of normotensive MAPs. Treatment of HTN in patients taking a BTKi is challenging and may require multiple antihypertensives. Patients with prior-HTN appear to benefit from combination regimens with BBs and HCTZ, whereas patients with de novo HTN appear to benefit from ACEi/ARBs with HCTZ. These results should be confirmed in prospective studies.

Evaluating population-level outcomes in Chronic Lymphocytic leukemia in the era of novel therapies using the SEER registry

In the last decade, novel agents such as BTK and BCL-2 inhibitors have revolutionized treatment of CLL/SLL, with clinical trials showing improved overall survival compared to chemotherapeutic agents. However, studies examining whether they have improved overall survival at the population level are lacking. We evaluated this by conducting a retrospective analysis of CLL/SLL patients registered in the National Cancer Institute's surveillance epidemiology and end results (SEER) database, analyzing overall survival (OS) in periods pre- and post-availability of novel agents, along with demographic information. Our results showed that median OS significantly improved over time [7.8 years (2000-2005), 9.1 years (2006-2013), and not reached (2014-2018) (p < 0.001)]. Compared to diagnosis in 2014-2018, diagnosis in earlier periods was associated with higher mortality risk (2000-2005-HR 1.32, 95 % CI 1.28-1.37, p < 0.001: 2006-2013-HR 1.09, 95 % CI 1.06-1.13, p < 0.001). Lower mortality risk was seen in patients age < 85 years whereas median household income of <$75000 was associated with higher mortality. Our study provides real-world data suggesting a possible multifactorial contribution to improvement in survival, including availability of novel agents, better monitoring, and supportive care. They also show discrepancies in overall survival for CLL/SLL patients due to socioeconomic status and demographic factors.

Current Therapeutic Sequencing in Chronic Lymphocytic Leukemia

The treatment landscape of chronic lymphocytic leukemia (CLL), the most frequent leukemia in adults, is constantly changing. CLL patients can be divided into three risk categories, based on their IGHV mutational status and the occurrence of TP53 disruption and/or complex karyotype. For the first-line treatment of low- and intermediate-risk CLL, both the BCL2 inhibitor venetoclax plus obinutuzumab and the second generation BTK inhibitors (BTKi), namely acalabrutinib and zanubrutinib, are valuable and effective options. Conversely, venetoclax-based fixed duration therapies have not shown remarkable results in high-risk CLL patients, while continuous treatment with acalabrutinib and zanubrutinib displayed favorable outcomes, similar to those obtained in TP53 wild-type patients. The development of acquired resistance to pathway inhibitors is still a clinical challenge, and the optimal treatment sequencing of relapsed/refractory CLL is not completely established. Covalent BTKi-refractory patients should be treated with venetoclax plus rituximab, whereas venetoclax-refractory CLL may be treated with second generation BTKi in the case of early relapse, while venetoclax plus rituximab might be used if late relapse has occurred. On these grounds, here we provide an overview of the current state-of-the-art therapeutic algorithms for treatment-naïve patients, as well as for relapsed/refractory disease.

In BTK, phosphorylated Y223 in the SH3 domain mirrors catalytic activity, but does not influence biological function

ABSTRACT

Bruton's tyrosine kinase (BTK) is an enzyme needed for B-cell survival, and its inhibitors have become potent targeted medicines for the treatment of B-cell malignancies. The initial activation event of cytoplasmic protein-tyrosine kinases is the phosphorylation of a conserved regulatory tyrosine in the catalytic domain, which in BTK is represented by tyrosine 551. In addition, the tyrosine 223 (Y223) residue in the SRC homology 3 (SH3) domain has, for more than 2 decades, generally been considered necessary for full enzymatic activity. The initial recognition of its potential importance stems from transformation assays using nonlymphoid cells. To determine the biological significance of this residue, we generated CRISPR-Cas-mediated knockin mice carrying a tyrosine to phenylalanine substitution (Y223F), maintaining aromaticity and bulkiness while prohibiting phosphorylation. Using a battery of assays to study leukocyte subsets and the morphology of lymphoid organs, as well as the humoral immune responses, we were unable to detect any difference between wild-type mice and the Y223F mutant. Mice resistant to irreversible BTK inhibitors, through a cysteine 481 to serine substitution (C481S), served as an additional immunization control and mounted similar humoral immune responses as Y223F and wild-type animals. Collectively, our findings suggest that phosphorylation of Y223 serves as a useful proxy for phosphorylation of phospholipase Cγ2 (PLCG2), the endogenous substrate of BTK. However, in contrast to a frequently held conception, this posttranslational modification is dispensable for the function of BTK.

Follow-up from the A041202 study shows continued efficacy of ibrutinib regimens for older adults with CLL

ABSTRACT

A041202 (NCT01886872) is a phase 3 study comparing bendamustine plus rituximab (BR) with ibrutinib and the combination of ibrutinib plus rituximab (IR) in previously untreated older patients with chronic lymphocytic leukemia (CLL). The initial results showed that ibrutinib-containing regimens had superior progression-free survival (PFS) and rituximab did not add additional benefits. Here we present an updated analysis. With a median follow-up of 55 months, the median PFS was 44 months (95% confidence interval [CI], 38-54) for BR and not yet reached in either ibrutinib-containing arm. The 48-month PFS estimates were 47%, 76%, and 76% for BR, ibrutinib, and IR, respectively. The benefit of ibrutinib regimens over chemoimmunotherapy was consistent across subgroups of patients defined by TP53 abnormalities, del(11q), complex karyotype, and immunoglobulin heavy chain variable region (IGHV). No significant interaction effects were observed between the treatment arm and del(11q), the complex karyotype, or IGHV. However, a greater difference in PFS was observed among the patients with TP53 abnormalities. There was no difference in the overall survival. Notable adverse events with ibrutinib included atrial fibrillation (afib) and hypertension. Afib was observed in 11 patients (pts) on BR (3%) and 67 pts on ibrutinib (18%). All-grade hypertension was observed in 95 pts on BR (27%) and 263 pts on ibrutinib (55%). These data show that ibrutinib regimens prolong PFS compared with BR for older patients with treatment-naïve CLL. These benefits were observed across subgroups, including high-risk groups. Strikingly, within the ibrutinib arms, there was no inferior PFS for patients with abnormalities in TP53, the highest risk feature observed in CLL. These data continue to demonstrate the efficacy of ibrutinib in treatment-naïve CLL.

Metabolic and toxicological considerations of Bruton's tyrosine kinase inhibitors for the treatment of chronic lymphocytic leukemia/small lymphocytic lymphoma

INTRODUCTION

Bruton tyrosine kinase inhibitors (BTKi) have been used for the management of human diseases since the approval of the first-in class agent, ibrutinib, by the Food and Drug Administration in 2013 for the treatment of patients with mantle cell lymphoma (MCL). Ibrutinib is a covalent inhibitor along with second-class BTKis: acalabrutinib and zanubrutinib. These well-tolerated agents have transformed the treatment landscape of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). A new class of these inhibitors, non-covalent, might become an answer to the emerging resistance by avoiding the sustained contact with the kinase binding domain.

AREAS COVERED

This article examines the chemical composition, mechanism of action, metabolic characteristics, and potential toxicity of inhibitors targeting Bruton tyrosine kinase. A comprehensive search was conducted across English-language articles in PubMed, Web of Science, and Google Scholar.

EXPERT OPINION

Bruton tyrosine kinase inhibitors have greatly enhanced the armamentarium against lymphoid malignancies including CLL/SLL. Their future lies in the choice of appropriate patients who will benefit from the treatment without significant adverse reaction. Combination chemotherapy-free fixed-duration regimens with targeted molecules will allow for MRD-driven approach in patients with CLL/SLL in the near future.

Cost Effectiveness of Zanubrutinib Versus Ibrutinib in Relapsed or Refractory Chronic Lymphocytic Leukemia

BACKGROUND

While the efficacy and safety of zanubrutinib have been established in relapsed or refractory chronic lymphocytic leukemia, the evidence on cost effectiveness is still lacking.

OBJECTIVE

We aimed to evaluate the cost effectiveness of zanubrutinib versus ibrutinib in relapsed or refractory chronic lymphocytic leukemia from the commercial payer perspective in the USA.

METHODS

A partitioned survival model was developed based on survival curves from the phase III ALPINE trial. We reconstructed patient-level data for each curve and conducted a parametric estimation to incorporate long-term clinical outcomes and treatment costs into the model. Medical costs and utilities were obtained from public data and previous cost-effectiveness studies. A discount rate of 3.0% per annum was applied and costs were adjusted to 2023 US dollars. The incremental cost-effectiveness ratio was calculated by dividing the incremental costs of zanubrutinib over ibrutinib by the incremental life-years or quality-adjusted life-years. Deterministic and probabilistic sensitivity analyses were performed to examine the robustness of the results.

RESULTS

Over a 10-year analysis period, the incremental cost-effectiveness ratio of zanubrutinib versus ibrutinib was $91,260 per life-year gained and $120,634 per quality-adjusted life-year gained, making it cost effective within a threshold of $150,000 per quality-adjusted life-year gained. The incremental cost-effectiveness ratio was most sensitive to drug acquisition costs and progression-free survival distributions, and the probability of zanubrutinib being cost effective was approximately 52.8%, with a 30.0% likelihood of dominance.

CONCLUSIONS

Zanubrutinib is likely to be cost effective versus ibrutinib in relapsed or refractory chronic lymphocytic leukemia in the USA, but the high threshold should be noted. Our findings may provide a basis for pricing strategy and reimbursement decisions for zanubrutinib.