Fixed-duration ibrutinib plus venetoclax for first-line treatment of CLL: primary analysis of the CAPTIVATE FD cohort

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.

BCL-2 and BTK inhibitors for chronic lymphocytic leukemia: current treatments and overcoming resistance

INTRODUCTION

In the last decade, BTK inhibitors and the BCL-2 inhibitor venetoclax have replaced immunochemotherapy in the treatment of CLL.

AREAS COVERED

This review describes the use of BTK inhibitors and BCL2 inhibitors in the treatment of naive and relapsed or refractory CLL, with particular attention to the mechanisms of resistance. It also addresses the management of double-refractory patients, and the discovery of novel drugs. The corpus of papers was obtained by a search of the PubMed and Google Scholar databases for articles in English.

EXPERT OPINION

Covalent BTK inhibitors and venetoclax are commonly recommended for previously-untreated and relapsed/refractory CLL. However, resistance to both drug classes can develop over time. As such, double-refractory patients are difficult to manage and novel approaches are urgently needed.

Fixed-duration pirtobrutinib plus venetoclax with or without rituximab in relapsed/refractory CLL: the phase 1b BRUIN trial

ABSTRACT

Pirtobrutinib is a highly selective, noncovalent (reversible) Bruton tyrosine kinase inhibitor (BTKi). Patients with relapsed or refractory (R/R) chronic lymphocytic leukemia (CLL) were treated with fixed-duration pirtobrutinib plus venetoclax (PV) or pirtobrutinib plus venetoclax and rituximab (PVR) in this phase 1b trial. Prior covalent BTKi therapy was allowed, but not prior treatment with venetoclax. Patients were assigned to receive PV (n = 15) or PVR (n = 10) for 25 cycles. Most patients (68%) had received prior covalent BTKi therapy. At the data cutoff date, the median time on study was 27.0 months for PV and 23.3 months for PVR. Overall response rates were 93.3% (95% confidence interval [CI], 68.1-99.8) for PV and 100% (95% CI, 69.2-100.0) for PVR, with 10 complete responses (PV: 7; PVR: 3). After 12 cycles of treatment, 85.7% (95% CI, 57.2-98.2) of PV and 90.0% (95% CI, 55.5-99.7) of PVR patients achieved undetectable minimal residual disease (<10-4) in peripheral blood. Progression-free survival at 18 months was 92.9% (95% CI, 59.1-99.0) for PV patients and 80.0% (95% CI, 40.9-94.6) for PVR patients. No dose-limiting toxicities were observed during the 5-week assessment period. The most common grade ≥3 adverse events (AEs) for all patients included neutropenia (52%) and anemia (16%). AEs led to dose reduction in 3 patients and discontinuation in 2. In conclusion, fixed-duration PV or PVR was well tolerated and had promising efficacy in patients with R/R CLL, including patients previously treated with a covalent BTKi. This trial was registered at www.clinicaltrials.gov as #NCT03740529.

The Novel Anti-Cancer Agent, SpiD3, Is Cytotoxic in CLL Cells Resistant to Ibrutinib or Venetoclax

Background

B-cell receptor (BCR) signaling is a central driver in chronic lymphocytic leukemia (CLL), along with the activation of pro-survival pathways (e.g., NF-κB) and aberrant anti-apoptotic mechanisms (e.g., BCL2) culminating to CLL cell survival and drug resistance. Front-line targeted therapies such as ibrutinib (BTK inhibitor) and venetoclax (BCL2 inhibitor) have radically improved CLL management. Yet, persisting CLL cells lead to relapse in ~20% of patients, signifying the unmet need of inhibitor-resistant refractory CLL. SpiD3 is a novel spirocyclic dimer of analog 19 that displays NF-κB inhibitory activity and preclinical anti-cancer properties. Recently, we have shown that SpiD3 inhibits CLL cell proliferation and induces cytotoxicity by promoting futile activation of the unfolded protein response (UPR) pathway and generation of reactive oxygen species (ROS), resulting in the inhibition of protein synthesis in CLL cells.

Methods

We performed RNA-sequencing using CLL cells rendered resistant to ibrutinib and venetoclax to explore potential vulnerabilities in inhibitor-resistant and SpiD3-treated CLL cells.

Results

The transcriptomic analysis of ibrutinib- or venetoclax-resistant CLL cell lines revealed ferroptosis, UPR signaling, and oxidative stress to be among the top pathways modulated by SpiD3 treatment. By examining SpiD3-induced protein aggregation, ROS production, and ferroptosis in inhibitor-resistant CLL cells, our findings demonstrate cytotoxicity following SpiD3 treatment in cell lines resistant to current front-line CLL therapeutics.

Conclusions

Our results substantiate the development of SpiD3 as a novel therapeutic agent for relapsed/refractory CLL disease.

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.

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.

Measurable residual disease (MRD)-testing in haematological cancers: A giant leap forward or sideways?

Measurable residual disease (MRD)-testing is used in many haematological cancers to estimate relapse risk and to direct therapy. Sometimes MRD-test results are used for regulatory approval. However, some people including regulators wrongfully believe results of MRD-testing are highly accurate and of proven efficacy in directing therapy. We review MRD-testing technologies and evaluate the accuracy of MRD-testing for predicting relapse and the strength of evidence supporting efficacy of MRD-guided therapy. We show that at the individual level MRD-test results are often an inaccurate relapse predictor. Also, no convincing data indicate that increasing therapy-intensity based on a positive MRD-test reduces relapse risk or improves survival. We caution against adjusting therapy-intensity based solely on results of MRD-testing.

Holding the therapy in CLLp53: mechanisms to achieve durable responses

Chronic lymphocytic leukemia (CLL) is a common leukemia, mainly affecting the elderly. Originating in the bone marrow, CLL involves the accumulation of B lymphocytes and progresses slowly, though 50-60% of patients will require therapy. At diagnosis, the presence of p53 protein aberrations, such as 17p deletion and TP53 mutation, arises in approximately one out of 10 patients. Even in the era of targeted therapies, these aberrations remain the most important prognostic factors. Current guidelines favor continuous BTK inhibitor therapy in patients with CLLp53, though adverse events and drug resistance may lead to discontinuation. Herein, we discuss the effects of B-cell receptor and BCL-2 inhibition, as well as the role of the immune system, in two elderly CLLp53 patients with prolonged responses to different therapies.

Targeting the tumor microenvironment for treating double-refractory chronic lymphocytic leukemia

ABSTRACT

The introduction of BTK inhibitors and BCL2 antagonists to the treatment of chronic lymphocytic leukemia (CLL) has revolutionized therapy and improved patient outcomes. These agents have replaced chemoimmunotherapy as standard of care. Despite this progress, a new group of patients is currently emerging, which has become refractory or intolerant to both classes of agents, creating an unmet medical need. Here, we propose that the targeted modulation of the tumor microenvironment provides new therapeutic options for this group of double-refractory patients. Furthermore, we outline a sequential strategy for tumor microenvironment-directed combination therapies in CLL that can be tested in clinical protocols.

Combination of BCL-2 inhibitors and immunotherapy: a promising therapeutic strategy for hematological malignancies

The rapid development of high-throughput sequencing in recent years has facilitated great progress in the molecular-targeted therapy of hematological malignancies, including leukemia, lymphoma, and multiple myeloma. BCL-2 inhibitors are among the most important molecular-targeted agents. Immunotherapy for hematologic malignancy has rapidly increased in popularity in recent years and has been proven to improve the overall survival rate. However, few clinical studies have investigated combination therapy with BCL-2 inhibitors and immunotherapies, such as immune molecule-targeted drugs or immune cell adoptive therapy. In this review, we discuss the drug discovery process, current clinical application status, and resistance and tolerance issues associated with BCL-2 inhibitors. We emphasize their important role in regulating the immune system and propose that the combination of BCL-2 inhibitors with immunotherapy may be one of the most promising treatment methods for hematologic malignancies.

What clinicians should know about surrogate end points in hematologic malignancies

ABSTRACT

Use of surrogates as primary end points is commonplace in hematology/oncology clinical trials. As opposed to prognostic markers, surrogates are end points that can be measured early and yet can still capture the full effect of treatment, because it would be captured by the true outcome (eg, overall survival). We discuss the level of evidence of the most commonly used end points in hematology and share recommendations on how to apply and evaluate surrogate end points in research and clinical practice. Based on the statistical literature, this clinician-friendly review intends to build a bridge between clinicians and surrogacy specialists.

Realizing precision medicine in chronic lymphocytic leukemia: Remaining challenges and potential opportunities

Patients with chronic lymphocytic leukemia (CLL) exhibit diverse clinical outcomes. An expanding array of genetic tests is now employed to facilitate the identification of patients with high-risk disease and inform treatment decisions. These tests encompass molecular cytogenetic analysis, focusing on recurrent chromosomal alterations, particularly del(17p). Additionally, sequencing is utilized to identify TP53 mutations and to determine the somatic hypermutation status of the immunoglobulin heavy variable gene. Concurrently, a swift advancement of targeted treatment has led to the implementation of novel strategies for patients with CLL, including kinase and BCL2 inhibitors. This review explores both current and emerging diagnostic tests aimed at identifying high-risk patients who should benefit from targeted therapies. We outline existing treatment paradigms, emphasizing the importance of matching the right treatment to the right patient beyond genetic stratification, considering the crucial balance between safety and efficacy. We also take into consideration the practical and logistical issues when choosing a management strategy for each individual patient. Furthermore, we delve into the mechanisms underlying therapy resistance and stress the relevance of monitoring measurable residual disease to guide treatment decisions. Finally, we underscore the necessity of aggregating real-world data, adopting a global perspective, and ensuring patient engagement. Taken together, we argue that precision medicine is not the mere application of precision diagnostics and accessibility of precision therapies in CLL but encompasses various aspects of the patient journey (e.g., lifestyle exposures and comorbidities) and their preferences toward achieving true personalized medicine for patients with CLL.

Defining treatment success in chronic lymphocytic leukemia: exploring surrogate markers, comorbidities, and patient-centered endpoints

INTRODUCTION

Traditionally, the success of chronic lymphocytic leukemia (CLL) treatment has been primarily assessed based on clinical outcomes, such as disease response, progression-free survival (PFS), and overall survival (OS). However, the evolution of treatment approaches recognizes the importance of a patient-centered perspective that includes factors directly affecting patients' quality of life and overall well-being.

AREAS COVERED

Studies addressing the impact of targeted agents on improving either OS or other endpoint surrogates were selected using PubMed and MEDLINE platforms. Our search also included studies that considered patient-centric endpoints such as health-related quality of life and patient-reported outcomes (PROs).

EXPERT OPINION

The changing landscape of CLL treatment underscores the importance of continually exploring various endpoints to thoroughly define treatment success. Beyond conventional metrics such as OS and surrogate endpoints, namely, PFS, time to next treatment (TTNT), and measurable residual disease (MRD) assessment, it becomes crucial to integrate enhanced comorbidity evaluations and patient-centered viewpoints into a CLL success roadmap.Subsequent investigations ought to concentrate on enhancing current surrogate endpoints, discerning their contextual significance, and exploring innovative indicators of treatment efficacy and safety. Given the dynamic nature of CLL and the heterogeneity among patient groups, personalized strategies are essential, taking into account individual traits and patient preferences.

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.

Outcomes with ibrutinib in patients with chronic lymphocytic leukaemia: Results from the German multicentre REALITY study

OBJECTIVES

To assess treatment adherence, effectiveness and safety outcomes of patients with chronic lymphocytic leukaemia (CLL) receiving ibrutinib in a real-world setting.

METHODS

Patients enrolled in REALITY were ≥18 years with a confirmed diagnosis of CLL and were receiving ibrutinib as a first-line (1L), 2L or ≥3L therapy. Treatment retention, adherence, progression-free survival (PFS), overall survival (OS) and time to next therapy were assessed at 1 and 2 years overall, by typology and by cytogenetic subgroups. PFS and OS were analysed using Kaplan-Meier methods.

RESULTS

Exactly 302 patients were enrolled across 57 sites in Germany, from January 2017 to July 2021. One-year retention rates were 69.9% overall (primary endpoint), 77.9% for 1L patients, and 77.6%/78.8% for high-risk patients with del17p/TP53. At 2 years, PFS/OS rates were 77.8%/90.7% overall (1L, 82.7%/90.4%), and were consistent across cytogenetic subgroups. PFS rates were higher for 1L versus ≥3L patients. Patients with the low-acceptance/low-control typology at baseline were less likely to retain treatment at 1 year versus the high-acceptance/high-control typology. No new safety signals were observed.

CONCLUSIONS

The REALITY study provides further evidence of the effectiveness and safety of ibrutinib in patients with CLL in a real-world setting, particularly in earlier treatment lines.

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.

The Safety of Novel Therapies in Chronic Lymphocytic Leukemia in the Era of Intermittent Fasting: A Pharmacology-Based Review

Intermittent fasting (IF) has recently gained popularity due to its emerging benefits in reducing weight and improving metabolic health. Concurrently, novel agents (NAs) like venetoclax and Bruton tyrosine kinase inhibitors (BTKIs) have revolutionized the treatment of chronic lymphocytic leukemia (CLL). Unfortunately, it is unclear whether the associated risks of tumor lysis syndrome (TLS) and gastrointestinal bleeding (GIB) are increased in IF practitioners receiving NAs. This review explored the literature available on the permissibility of IF in CLL patients undergoing treatment with first-line NAs (FLNAs). Literature was scoped to identify IF patterns and the available data on TLS and GIB risks associated with food and fluid intake in CLL patients receiving FLNAs. Although current evidence is insufficient to recommend IF in this population, it may be possible for patients on venetoclax to conservatively practice fluid-liberal IF, provided that adequate hydration and the consistent administration of food are achieved. In contrast, considering the significant risk of TLS and the pharmacokinetics of venetoclax, patients should be discouraged from practicing fluid-restricted IF, especially during the ramp-up phase. Moreover, patients on BTKIs ought to refrain from IF due to the possible risk of GIB until further data are available. Further research is needed to provide conclusive recommendations.

Monitoring Response and Resistance to Treatment in Chronic Lymphocytic Leukemia

The recent evolution in chronic lymphocytic leukemia (CLL) targeted therapies led to a progressive change in the way clinicians manage the goals of treatment and evaluate the response to treatment in respect to the paradigm of the chemoimmunotherapy era. Continuous therapies with BTK inhibitors achieve prolonged and sustained control of the disease. On the other hand, venetoclax and anti-CD20 monoclonal antibodies or, more recently, ibrutinib plus venetoclax combinations, given for a fixed duration, achieve undetectable measurable residual disease (uMRD) in the vast majority of patients. On these grounds, a time-limited MRD-driven strategy, a previously unexplored scenario in CLL, is being attempted. On the other side of the spectrum, novel genetic and non-genetic mechanisms of resistance to targeted treatments are emerging. Here we review the response assessment criteria, the evolution and clinical application of MRD analysis and the mechanisms of resistance according to the novel treatment strategies within clinical trials. The extent to which this novel evidence will translate in the real-life management of CLL patients remains an open issue to be addressed.

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.

Chronic Lymphocytic Leukemia: Management of Adverse Events in the Era of Targeted Agents

The treatment landscape for CLL has undergone a profound transformation with the advent of targeted agents (TAs) like Bruton's Tyrosine Kinase inhibitors (BTKis) and BCL-2 inhibitors (BCL-2is). These agents target crucial cellular pathways in CLL, offering superior efficacy over traditional chemo-immunotherapy, which has led to improved progression-free and overall survival rates. This advancement promises enhanced disease control and potentially normal life expectancy for many patients. However, the journey is not without challenges, as these TAs are associated with a range of adverse events (AEs) that can impact treatment efficacy and patient quality of life. This review focuses on detailing the various AEs related to TA management in CLL, evaluating their frequency and clinical impact. The aim is to present a comprehensive guide to the effective management of these AEs, ensuring optimal tolerability and efficacy of TAs. By reviewing the existing literature and consolidating findings, we provide insights into AE management, which is crucial for maximizing patient outcomes in CLL therapy.

BTK inhibitors in CLL: second-generation drugs and beyond

ABSTRACT

BTK inhibitors (BTKis) are established standards of care in multiple B-cell malignancies including chronic lymphocytic leukemia, mantle cell lymphoma, and Waldenstrom macroglobulinemia. The first-generation BTKi ibrutinib demonstrated superiority over standard chemoimmunotherapy regimens in multiple randomized trials but is limited by cardiovascular side effects such as atrial fibrillation and hypertension. Second-generation BTKis have improved selectivity and demonstrate reduced rates of cardiovascular complications in 3 head-to-head ibrutinib studies. The emergence of BTK C481S mutation has led to the development of noncovalent, "reversible" BTKis, such as pirtobrutinib, which are agnostic to the C481S mutation. However, these inhibitors are associated with resistant mutations outside the C481 hot spot. These variant non-C481 mutations are of great clinical interest because some are shared among pirtobrutinib, zanubrutinib, and acalabrutinib, with potential implications for cross resistance and treatment sequencing. Finally, BTK protein degraders with in vitro activity against C481 and non-C481 mutations are currently in clinical development. Here, we review the evolution of therapeutic BTK-targeting and discuss future directions for clinical research.

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.

Beyond Chemotherapy: Present and Future Perspectives in the Treatment of Lymphoproliferative Disorders

Over the past three decades, the treatment of lymphoproliferative disorders has undergone profound changes, notably due to the increasing availability of innovative therapies with the potential to redefine clinical management paradigms. A major impact is related to the development of monoclonal antibodies, checkpoint inhibitors, bispecific antibodies, and chimeric antigen receptor T (CAR-T) cell therapies. This review discusses the current landscape of clinical trials targeting various hematological malignancies, highlighting promising early-phase results and strategies to overcome resistance. Lymphoproliferative disorders encompass a range of conditions: while in Hodgkin lymphoma (HL) the goal is to reduce chemotherapy-related toxicity by integrating immunotherapy into the frontline setting, peripheral T cell lymphoma (PTCL) lacks effective targeted therapies. The review emphasizes a shifting therapeutic landscape towards precision medicine and treatment modalities that are less toxic yet more effective.

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.

Treatment of Richter's Transformation with Novel Therapies

PURPOSE OF REVIEW

This review presents recently published clinical trial data and ongoing investigations regarding the treatment of Richter's transformation (RT).

RECENT FINDINGS

Recently, numerous approaches have been investigated for the treatment of RT including: traditional chemoimmunotherapy regimens combined with targeted agents such as BTKi and BCL2i; immunotherapy combined with targeted agents; non-covalent BTKis; bispecific T cell engagers; and CART therapy. In addition, various novel targeted agents are currently being studied for the treatment of RT in phase 1 and 2 clinical trials. Standard of care treatment with chemoimmunotherapy for RT has limited efficacy in achieving durable remissions. Here, we review recent data on the use of combination treatments and targeted agents in RT. Although some progress has been made in the investigation to optimize treatment of RT, further study is needed to evaluate long term outcomes of recently published trials and test efficacy of upcoming novel agents.

Therapeutic targeting of apoptosis in chronic lymphocytic leukemia

Therapeutic targeting of apoptosis with small molecule B-cell lymphoma 2 (BCL-2) inhibition with venetoclax is highly efficacious in CLL, leading to sustained deep responses, particularly among patients with treatment-naïve disease with favorable prognostic markers. Patients with unfavorable genetic characteristics such as TP53 aberration and unmutated IGHV may also derive durable benefits, but their remission duration after time-limited venetoclax-containing combination therapy is shorter, particularly in patients with relapsed/refractory disease. Emerging data indicate that the context of disease progression after initial treatment with venetoclax may define the success of re-treatment with venetoclax. Specifically, continuous venetoclax exposure may select for resistant disease due to genetic mechanisms such as BCL2 mutations and functional resistance mechanisms such as hyperphosphorylation of BCL-2 family proteins, which decrease the affinity of venetoclax binding to the target or lead to increased MCL-1 dependence and concomitant decrease in BCL-2 dependence. These patients may be best served by switching to a different class of targeted agents at the time of progression. In contrast, relapsed CLL that arises while being off therapy after a period of time-limited venetoclax-based regimens maintains sensitivity to re-treatment with venetoclax for the majority of patients. Novel strategies related to therapeutic targeting of apoptosis include next-generation BCL-2 inhibitors with improved potency and pharmacokinetic profiles, direct targeting of anti-apoptotic BH3 family proteins beyond BCL-2 such as MCL-1, and indirect targeting of MCL-1 through mechanisms such as small molecule cyclin-dependent kinase 9 inhibitors.

Frontline Therapy of CLL-Changing Treatment Paradigms

PURPOSE OF REVIEW

The therapeutic landscape for chronic lymphocytic leukemia (CLL) has undergone a complete makeover following the introduction of highly effective targeted therapies, beginning with ibrutinib which first attained regulatory approval for CLL in 2014.

RECENT FINDINGS

In recent years, we have seen further refinement of therapeutic options with the development of newer-generation Bruton's tyrosine kinase inhibitors (BTKi) including acalabrutinib and zanubrutinib that improve upon the safety of ibrutinib. Additionally, venetoclax-based approaches, combined with anti-CD20 antibodies, have allowed for time-limited targeted therapeutic strategies which are particularly attractive for certain subsets of patients though have demonstrated efficacy across all subgroups. Lastly, there is an ongoing movement toward the development of time-limited strategies inclusive of both a BTKi and venetoclax that may further widen potential options. CLL patients requiring frontline therapy have a unique burden of choice between highly effective therapies that differ substantially with respect to side effect profiles and schedules. This review will focus on the frontline management of CLL in the setting of these rapidly changing options.

Targeting the B cell receptor signaling pathway in chronic lymphocytic leukemia

Aberrant signal transduction through the B cell receptor (BCR) plays a critical role in the pathogenesis of chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). BCR-dependent signaling is necessary for the growth and survival of neoplastic cells, making inhibition of down-stream pathways a logical therapeutic strategy. Indeed, selective inhibitors against Bruton's tyrosine kinase (BTK) and phosphoinositide 3-kinase (PI3K) have been shown to induce high rates of response in CLL and other B cell lymphomas. In particular, the development of BTK inhibitors revolutionized the treatment approach to CLL, demonstrating long-term efficacy. While BTK inhibitors are widely used for multiple lines of treatment, PI3K inhibitors are much less commonly utilized, mainly due to toxicities. CLL remains an incurable disease and effective treatment options after relapse or development of TKI resistance are greatly needed. This review provides an overview of BCR signaling, a summary of the current therapeutic landscape, and a discussion of the ongoing trials targeting BCR-associated kinases.

Innovative Combinations, Cellular Therapies and Bispecific Antibodies for Chronic Lymphocytic Leukemia: A Narrative Review

In the last few years, several agents targeting molecules that sustain the survival and the proliferation of chronic lymphocytic leukemia (CLL) cells have become clinically available. Most of these drugs target surface proteins, such as CD19 or CD20, via monoclonal or bispecific monoclonal antibodies (BsAbs), CAR T cells, intracellular proteins like BTK by using covalent or non-covalent inhibitors or BCL2 with first or second generation BH3-mimetics. Since the management of CLL is evolving quickly, in this review we highlighted the most important innovative treatments including novel double and triple combination therapies, CAR T cells and BsAbs for CLL. Recently, a large number of studies on novel combinations and newer strategic options for CLL therapy have been published or presented at international conferences, which were summarized and linked together. Although the management of treatment with a single continuous agent is easier, the emergence of protein mutations, long-term toxicities and costs are important concerns that favor the use of a fixed duration therapy. In the future, a measurable residual disease (MRD)-guided treatment cessation and MRD-based re-initiation of targeted therapy seems to be a more feasible approach, allowing identification of the patients who might benefit from continuous therapy or who might need a consolidation with BsAbs or CAR T cells to clear the neoplastic clone.

Final results on effectiveness and safety of Ibrutinib in patients with chronic lymphocytic leukemia from the non-interventional FIRE study

We conducted an observational study (FIRE) to understand the effectiveness and safety outcomes of ibrutinib in patients with chronic lymphocytic leukemia (CLL) in France, after a maximum follow-up of five years. Patients were included according to the French marketing authorization in 2016 (i.e. patients with relapsed or refractory CLL or to previously untreated CLL patients with deletion 17p and/or tumor protein p53 mutations unsuitable for chemoimmunotherapy) and could have initiated ibrutinib more than 30 days prior their enrolment in the study (i.e. retrospective patients) or between 30 days before and 14 days after their enrolment (i.e. prospective patients). The results showed that in the effectiveness population (N = 388), the median progression-free survival (PFS) was 53.1 (95% CI: 44.5-60.5) months for retrospective patients and 52.9 (95% CI: 40.3-60.6) months for prospective patients and no difference was shown between the PFS of patients who had at least one dose reduction versus the PFS of patients without dose reduction (p = 0.7971 for retrospective and p = 0.3163 for prospective patients). For both retrospective and prospective patients, the median overall survival was not reached. The most frequent treatment-emergent adverse event of interest was infections (57.6% retrospective; 71.4% prospective). A total of 14.6% of the retrospective patients and 22.4% of the prospective patients had an adverse event leading to death. Our findings on effectiveness were consistent with other studies and the fact that patients with dose reductions had similar PFS than patients without dose reduction is reassuring. No additional safety concerns than those already mentioned in previous studies could be noticed.Trial registration ClinicalTrials.gov, NCT03425591. Registered 1 February 2018 - Retrospectively registered.

How receptor tyrosine kinase-like orphan receptor 1 meets its partners in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common leukemia in western societies, recognized by clinical and molecular heterogeneity. Despite the success of targeted therapies, acquired resistance remains a challenge for relapsed and refractory CLL, as a consequence of mutations in the target or the upregulation of other survival pathways leading to the progression of the disease. Research on proteins that can trigger such pathways may define novel therapies for a successful outcome in CLL such as the receptor tyrosine kinase-like orphan receptor 1 (ROR1). ROR1 is a signaling receptor for Wnt5a, with an important role during embryogenesis. The aberrant expression on CLL cells and several types of tumors, is involved in cell proliferation, survival, migration as well as drug resistance. Antibody-based immunotherapies and small-molecule compounds emerged to target ROR1 in preclinical and clinical studies. Efforts have been made to identify new prognostic markers having predictive value to refine and increase the detection and management of CLL. ROR1 can be considered as an attractive target for CLL diagnosis, prognosis, and treatment. It can be clinically effective alone and/or in combination with current approved agents. In this review, we summarize the scientific achievements in targeting ROR1 for CLL diagnosis, prognosis, and treatment.

Venetoclax Initiation in Chronic Lymphocytic Leukemia: International Insights and Innovative Approaches for Optimal Patient Care

Venetoclax, a highly selective, oral B-cell lymphoma 2 inhibitor, provides a robust targeted-therapy option for the treatment of chronic lymphocytic leukemia (CLL), including patients with high-risk del(17p)/mutated-TP53 and immunoglobulin heavy variable region unmutated CLL and those refractory to chemoimmunotherapy across all age groups. Due to the potent pro-apoptotic effect of venetoclax, treatment initiation carries a risk of tumor lysis syndrome (TLS). Prompt and appropriate management is needed to limit clinical TLS, which may entail serious adverse events and death. Venetoclax ramp-up involves gradual, stepwise increases in daily venetoclax dosing from 20 mg to 400 mg (target dose) over 5 weeks; adherence to on-label scheduling provides a tumor debulking phase, reducing the risk of TLS. The key components of safe venetoclax therapy involve assessment (radiographic evaluation and baseline blood chemistry), preparation (adequate hydration), and initiation (blood chemistry monitoring). In addition to summarizing the evidence for venetoclax's efficacy and safety, this review uses hypothetical patient scenarios based on risk level for TLS (high, medium, low) to share the authors' clinical experience with venetoclax initiation and present global approaches utilized in various treatment settings. These hypothetical scenarios highlight the importance of a multidisciplinary approach and shared decision-making, outlining best practices for venetoclax initiation and overall optimal treatment strategies in patients with CLL.

Update on the management of relapsed/refractory chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) predominantly affects older adults, characterized by a relapsing and remitting pattern with sequential treatments available for many patients. Identification of progressive/relapsed CLL should prompt close monitoring and early discussion about the next therapies when treatment indications are present. The intervening period represents an opportunity to optimize patient health, including establishing adequate vaccination and surveillance for second primary malignancies, and treating non-CLL-related comorbidities which may impact well-being and CLL therapy. We now see patients with relapsed/refractory (RR) CLL in the clinic who have been previously treated with chemoimmunotherapy (CIT) and/or one or more novel therapies. Continuous covalent inhibitors of Bruton's tyrosine kinase (cBTKi) and fixed-duration venetoclax (Ven)-anti-CD20 monoclonal antibody (mAb) are preferred over CIT given the survival advantages associated with these therapies, although have never been evaluated head-to-head. While both classes are effective for RR CLL, potential side effects and the logistics of administration differ. Few randomized data demonstrate the sequential use of cBTKi and fixed-duration Ven-anti-CD20 mAb; however, they may be used in either sequence. Newer non-covalent BTKi, active against BTK C481 resistance mutations emerging with continuous cBTKi exposure, and novel approaches such as BTK degraders, bispecific antibodies, and chimeric antigen receptor T-cell therapies demonstrate impressive efficacy. In this review of RR CLL we explore relevant investigations, consideration of broader CLL- and non-CLL-related health needs, and evidence for efficacy and safety of B-cell receptor inhibitors and Ven, including available data to support drug sequencing or switching. We describe novel approaches to RR CLL, including rechallenging with fixed-duration therapies, allogeneic stem cell transplant indications in the novel therapy era, and highlight early data supporting the use of T-cell directing therapies and novel drug targets.

Chronic Lymphocytic Leukemia: Time-Limited Therapy in the First-Line Setting and Role of Minimal Residual Disease

PURPOSE OF REVIEW

In this review, we provide an overview of different time-limited combination therapies of chronic lymphocytic leukemia (CLL) and summarize the data of pivotal clinical studies. Furthermore, we discuss the relevance of MRD in clinical trials and summarize the challenges that arise in routine clinical care. Finally, we provide an outlook on studies and datasets needed to optimize the use of time-limited treatment strategies and MRD assessments in modern CLL management.

RECENT FINDINGS

In recent years, first-line treatment of CLL has undergone a considerable transformation, with targeted substances having largely replaced chemoimmunotherapy (CIT) as a time-limited strategy in the frontline setting. BTK inhibitors were the first class of targeted agents introduced in CLL, which achieved longer progression-free survival (PFS) and in some cases also overall survival (OS) than CIT. However, this required an indefinite drug intake until disease progression, while CIT is generally administered over the course of few months. In contrast to BTK inhibitors, BCL2 inhibitors, another class of targeted agents, can achieve high rates of undetectable minimal residual disease (uMRD) levels and induce deep molecular remissions with the potential to stop treatment while maintaining remissions. Combinations of BCL2 inhibitors with CD20 antibodies or with BTK inhibitors have been explored to establish time-limited treatment strategies with targeted agents. In this context, one of the strongest predictors of long-term outcomes is MRD status at the end of treatment, which has been shown to correlate closely with PFS and OS in most cases.

Absence of BTK, BCL2, and PLCG2 Mutations in Chronic Lymphocytic Leukemia Relapsing after First-Line Treatment with Fixed-Duration Ibrutinib plus Venetoclax

PURPOSE

Mutations in BTK, PLCG2, and BCL2 have been reported in patients with progressive disease (PD) on continuous single-agent BTK or BCL2 inhibitor treatment. We tested for these mutations in samples from patients with PD after completion of first-line treatment with fixed-duration ibrutinib plus venetoclax for chronic lymphocytic leukemia (CLL) in the phase II CAPTIVATE study.

PATIENTS AND METHODS

A total of 191 patients completed fixed-duration ibrutinib plus venetoclax (three cycles of ibrutinib then 12-13 cycles of ibrutinib plus venetoclax). Genomic risk features [del(11q), del(13q), del(17p), trisomy 12, complex karyotype, unmutated IGHV, TP53 mutated] and mutations in genes recurrently mutated in CLL (ATM, BIRC3, BRAF, CHD2, EZH2, FBXW7, MYD88, NOTCH1, POT1, RPS15, SF3B1, XPO1) were assessed at baseline in patients with and without PD at data cutoff; gene variants and resistance-associated mutations in BTK, PLCG2, or BCL2 were evaluated at PD.

RESULTS

Of 191 patients completing fixed-duration ibrutinib plus venetoclax, with median follow-up of 38.9 months, 29 (15%) developed PD. No baseline risk feature or gene mutation was significantly associated with development of PD. No previously reported resistance-associated mutations in BTK, PLCG2, or BCL2 were detected at PD in 25 patients with available samples. Of the 29 patients with PD, 19 have required retreatment (single-agent ibrutinib, n = 16, or ibrutinib plus venetoclax, n = 3); 17 achieved partial response or better, 1 achieved stable disease, and 1 is pending response assessment.

CONCLUSIONS

First-line fixed-duration combination treatment with ibrutinib plus venetoclax may mitigate development of resistance mechanisms associated with continuous single-agent targeted therapies, allowing for effective retreatment. See related commentary by Al-Sawaf and Davids, p. 471.

Treatment of Double-Refractory Chronic Lymphocytic Leukemia-An Unmet Clinical Need

Recent years have seen significant improvement in chronic lymphocytic leukemia (CLL) management. Targeting B-cell lymphoma (BCL-2) and Bruton's kinase (BTK) have become the main strategies to restrain CLL activity. These agents are generally well tolerated, but the discontinuation of these therapies happens due to resistance, adverse effects, and Richter's transformation. A growing population of patients who have previously used both BTK inhibitors and BCL2 suffer from the constriction of the following regimens. This review explores the resistance mechanisms for both ibrutinib and venetoclax. Moreover, we present innovative approaches evaluated for treating double-refractory CLL.

Chronic Lymphocytic Leukemia Therapy Guided by Measurable Residual Disease

BACKGROUND

The combination of ibrutinib and venetoclax has been shown to improve outcomes in patients with chronic lymphocytic leukemia (CLL) as compared with chemoimmunotherapy. Whether ibrutinib-venetoclax and personalization of treatment duration according to measurable residual disease (MRD) is more effective than fludarabine-cyclophosphamide-rituximab (FCR) is unclear.

METHODS

In this phase 3, multicenter, randomized, controlled, open-label platform trial involving patients with untreated CLL, we compared ibrutinib-venetoclax and ibrutinib monotherapy with FCR. In the ibrutinib-venetoclax group, after 2 months of ibrutinib, venetoclax was added for up to 6 years of therapy. The duration of ibrutinib-venetoclax therapy was defined by MRD assessed in peripheral blood and bone marrow and was double the time taken to achieve undetectable MRD. The primary end point was progression-free survival in the ibrutinib-venetoclax group as compared with the FCR group, results that are reported here. Key secondary end points were overall survival, response, MRD, and safety.

RESULTS

A total of 523 patients were randomly assigned to the ibrutinib-venetoclax group or the FCR group. At a median of 43.7 months, disease progression or death had occurred in 12 patients in the ibrutinib-venetoclax group and 75 patients in the FCR group (hazard ratio, 0.13; 95% confidence interval [CI], 0.07 to 0.24; P<0.001). Death occurred in 9 patients in the ibrutinib-venetoclax group and 25 patients in the FCR group (hazard ratio, 0.31; 95% CI, 0.15 to 0.67). At 3 years, 58.0% of the patients in the ibrutinib-venetoclax group had stopped therapy owing to undetectable MRD. After 5 years of ibrutinib-venetoclax therapy, 65.9% of the patients had undetectable MRD in the bone marrow and 92.7% had undetectable MRD in the peripheral blood. The risk of infection was similar in the ibrutinib-venetoclax group and the FCR group. The percentage of patients with cardiac serious adverse events was higher in the ibrutinib-venetoclax group than in the FCR group (10.7% vs. 0.4%).

CONCLUSIONS

MRD-directed ibrutinib-venetoclax improved progression-free survival as compared with FCR, and results for overall survival also favored ibrutinib-venetoclax. (Funded by Cancer Research UK and others; FLAIR ISRCTN Registry number, ISRCTN01844152; EudraCT number, 2013-001944-76.).

Targeting TP53 disruption in chronic lymphocytic leukemia: Current strategies and future directions

In the modern era of Chronic Lymphocytic Leukemia (CLL) targeted therapy, the loss of p53 function due to genetic abnormalities remains a significant challenge. This is because even targeted agents, which are currently the mainstay of treatment for CLL, do not directly target p53 or restore its disrupted pathway. Consequently, resistance to therapy and unfavorable clinical outcomes often accompany these p53-related abnormalities. An essential goal of future clinical research should be to address the ostensibly "undruggable" p53 pathway. Currently, multiple therapeutic approaches are being explored to tackle TP53 dysfunction and improve outcomes in high-risk CLL. These approaches include the use of oncoprotein murine double minute 2 inhibitors, small-molecule p53 reactivators, exportin 1 (XPO1) inhibitors, and ataxia-telangiectasia mutated and Rad3-related (ATR) inhibitors. Combinations of these p53-targeting strategies, along with established novel therapies such as B-cell receptor or B-cell lymphoma-2 (BCL-2) inhibitors, may shape the future of therapeutic trials in this challenging-to-treat disease.

Treatment of Chronic Lymphocytic Leukemia in the Personalized Medicine Era

Chronic lymphocytic leukemia is a lymphoproliferative disorder marked by the expansion of monoclonal, mature CD5+CD23+ B cells in peripheral blood, secondary lymphoid tissues, and bone marrow. The disease exhibits significant heterogeneity, with numerous somatic genetic alterations identified in the neoplastic clone, notably mutated TP53 and immunoglobulin heavy chain mutational statuses. Recent studies emphasize the pivotal roles of genetics and patient fragility in treatment decisions. This complexity underscores the need for a personalized approach, tailoring interventions to individual genetic profiles for heightened efficacy. The era of personalized treatment in CLL signifies a transformative shift, holding the potential for improved outcomes in the conquest of this intricate hematologic disorder. This review plays a role in elucidating the evolving CLL treatment landscape, encompassing all reported genetic factors. Through a comprehensive historical analysis, it provides insights into the evolution of CLL management. Beyond its retrospective nature, this review could be a valuable resource for clinicians, researchers, and stakeholders, offering a window into the latest advancements. In essence, it serves as a dynamic exploration of our current position and the promising prospects on the horizon.

Dual-targeted regimens for the frontline treatment of CLL

The treatment landscape of chronic lymphocytic leukemia (CLL) has evolved considerably over the past decade due to the development of effective novel agents with varying mechanisms of action, including Bruton tyrosine kinase (BTK) and B-cell lymphoma 2 (BCL2) inhibitors. Extrapolating upon the success of anti-CD20-directed chemoimmunotherapy, a dual-targeted approach has been explored in treatment-naive patients with CLL. Anti-CD20 monoclonal antibody combinations with BTK inhibitors as well as BCL2 inhibitors have demonstrated superiority over traditional cytotoxic chemoimmunotherapy regimens such as fludarabine, cyclophosphamide, and rituximab; bendamustine-rituximab; and obinutuzumab-chlorambucil. Impressive clinical benefit is seen in both younger and older patients, those with comorbidities, and, most importantly, those with poor prognostic features. Given this success, combinations of BTK inhibitors and venetoclax have been explored in clinical trials. These dual-targeted regimens provide remarkable efficacy while allowing for an all-oral approach and fixed duration of treatment. Current investigations under way are evaluating the utility of a triplet approach with the addition of obinutuzumab in comparison to a doublet approach.

Fixed-duration ibrutinib-venetoclax versus chlorambucil-obinutuzumab in previously untreated chronic lymphocytic leukaemia (GLOW): 4-year follow-up from a multicentre, open-label, randomised, phase 3 trial

BACKGROUND

In the GLOW study, fixed-duration ibrutinib-venetoclax showed superior progression-free survival versus chlorambucil-obinutuzumab in patients with previously untreated chronic lymphocytic leukaemia who were older or had comorbidities, or both, at a median follow up of 27·7 months. In this Article, we report updated outcomes from GLOW after a 46-month median follow-up.

METHODS

GLOW was a randomised, multicentre, phase 3 study done at 67 hospital centres across 14 countries. Patients aged 65 years and older or 18-64 years with previously untreated chronic lymphocytic leukaemia and a cumulative illness rating scale score of more than 6 or creatinine clearance less than 70 mL/min, or both, and an Eastern Cooperative Oncology Group performance status of 2 or less were randomly assigned (1:1) via an interactive web system with permuted blocks (block size of four) and stratified by IGHV mutational status and the presence of del11q aberration to the ibrutinib-venetoclax group (three cycles of ibrutinib lead-in [420 mg/day, orally], followed by 12 cycles of ibrutinib plus venetoclax [400 mg/day, orally, including a 5-week dose ramp-up]) or the chlorambucil-obinutuzumab group (six cycles of chlorambucil [0·5 mg/kg, orally, on days 1 and 15 of each cycle], and obinutuzumab [1000 mg, intravenously, on days 1 (or 100 mg on day 1 and 900 mg on day 2), 8, and 15 of cycle 1 and day 1 of cycles 2-6]). The primary endpoint was progression-free survival in the intention-to-treat population, assessed by an independent review committee. The safety population included all randomised patients who received at least one dose of the study treatment. This study is registered with ClinicalTrials.gov (NCT03462719) and the EU Clinical Trials Register (EudraCT 2017-004699-77).

FINDINGS

Between May 4, 2018, and April 5, 2019, 211 patients (122 [58%] were male and 89 [42%] were female) were randomly assigned to receive ibrutinib-venetoclax (n=106) or chlorambucil-obinutuzumab (n=105). At a median of 46 months (IQR 43-47) of follow-up, progression-free survival remained superior for the ibrutinib-venetoclax group (hazard ratio 0·214 [95% CI 0·138-0·334]; p<0·0001); 42-month progression-free survival rates were 74·6% (95% CI 65·0-82·0) for ibrutinib-venetoclax and 24·8% (16·5-34·1) for chlorambucil-obinutuzumab. Following the primary analysis, one patient in the chlorambucil-obinutuzumab group had a serious adverse event of myelodysplastic syndrome. Treatment-related deaths were reported in one patient receiving ibrutinib-venetoclax (cardiac failure, pneumonia, and sinus node dysfunction) and in one patient receiving chlorambucil-obinutuzumab (pneumonia). There were 15 deaths in the ibrutinib-venetoclax group (of which three were due to post-treatment infections) and 30 deaths in the chlorambucil-obinutuzumab group (of which 10 were due to post-treatment infections).

INTERPRETATION

After 4 years of follow-up, ibrutinib-venetoclax continues to significantly prolong progression-free survival (vs chemoimmunotherapy) in patients with previously untreated chronic lymphocytic leukaemia, supporting its use as a first-line option.

FUNDING

Janssen Research & Development and Pharmacyclics.

CAR-modified Cellular Therapies in Chronic Lymphocytic Leukemia: Is the Uphill Road Getting Less Steep?

The clinical development of chimeric antigen receptor (CAR) T-cell therapy has been more challenging for chronic lymphocytic leukemia (CLL) compared to other settings. One of the main reasons is the CLL-associated state of immune dysfunction that specifically involves patient-derived T cells. Here, we provide an overview of the clinical results obtained with CAR T-cell therapy in CLL, describing the identified immunologic reasons for the inferior efficacy. Novel CAR T-cell formulations, such as lisocabtagene maraleucel, administered alone or in combination with the Bruton tyrosine kinase inhibitor ibrutinib, are currently under investigation. These approaches are based on the rationale that improving the quality of the T-cell source and of the CAR T-cell product may deliver a more functional therapeutic weapon. Further strategies to boost the efficacy of CAR T cells should rely not only on the production of CAR T cells with an improved cellular composition but also on additional changes. Such alterations could include (1) the coadministration of immunomodulatory agents capable of counteracting CLL-related immunological alterations, (2) the design of improved CAR constructs (such as third- and fourth-generation CARs), (3) the incorporation into the manufacturing process of immunomodulatory compounds overcoming the T-cell defects, and (4) the use of allogeneic CAR T cells or alternative CAR-modified cellular vectors. These strategies may allow to develop more effective CAR-modified cellular therapies capable of counteracting the more aggressive and still incurable forms of CLL.

Real-life diagnostic and therapeutic approach to CLL: a 2022 update from an expert panel in Tuscany

A panel of chronic lymphocytic leukemia (CLL) experts from Tuscany propose a real-life diagnostic and therapeutic approach CLL that considers the role of genomic and somatic prognostic factors in risk stratification and treatment decisions. Safety and efficacy of new agents has been demonstrated now not only in clinical trials but also in many real-world series. The BTK inhibitors, ibrutinib and acalabrutinib, and BH3 mimetic venetoclax are now indicated as first-line therapy and chemoimmunotherapy can be spared to the majority of CLL patients, thus preventing unnecessary hematological and non-hematological toxicity and second primary tumors. For treatment, FISH for 17 p and P53 mutational status are essential. IGHV mutation can be done at diagnosis or before treatment. Echography is the gold standard radiological investigation in CLL, at both diagnosis and response evaluation. Chemotherapy is virtually abandoned. Age, genetic risk, and patient comorbidities have to be carefully evaluated for treatment decision. With the availability of different drugs, there is a need for a uniform and shared approach in daily therapeutic choice. The proposed approach is based on current evidence and guidelines as well as results from clinical trials and daily clinical experience.