Activity of venetoclax in patients with relapsed or refractory chronic lymphocytic leukaemia: analysis of the VENICE-1 multicentre, open-label, single-arm, phase 3b trial

SOHO State of the Art Updates and Next Questions | Venetoclax + Obinutuzumab Therapy in Chronic Lymphocytic Leukemia

In the past decade, the treatment paradigm for chronic lymphocytic leukemia (CLL) has markedly shifted from traditional chemoimmunotherapy towards targeted therapies.1 A fixed-duration, targeted regimen with venetoclax, a potent oral BCL-2 inhibitor, combined with obinutuzumab, a glycoengineered type II anti-CD20 monoclonal antibody (Ven-Obi), has become the standard to beat for time-limited therapy in CLL. Ven-Obi allows for the rapid induction of remissions with high rates of undetectable minimal residual disease (uMRD) in patients across different treatment settings. This strategy enables the discontinuation of therapy while maintaining treatment-free remissions for several years in many patients. With up to 6-year data now available from the pivotal phase 3 trial of this combination in CLL, this review aims to examine the evolving role of this strategy in CLL management, including updated data for safety and efficacy in randomized trials in both the frontline and relapsed/refractory (R/R) settings. We also explore real-world data for this combination, and review related issues, such as MRD monitoring, the potential for venetoclax retreatment or consolidative strategies and evaluate ongoing trials comparing this regimen as a standard of care control arm versus novel (including all-oral) therapeutic combinations.

The Impact of Minimal Residual Disease Measurement in the Management of Chronic Lymphocytic Leukemia

Background: The treatment of chronic lymphocytic leukemia (CLL) has advanced considerably in recent years. Bruton's tyrosine kinase inhibitors (BTKis) and B-cell lymphoma 2 inhibitors (BCL2is) such as venetoclax have largely supplanted chemoimmunotherapy for both frontline and relapsed CLL. With the introduction of additional innovative agents and regimens, the clinical role of measurable residual disease (MRD) has become complicated. Methods: In this article, we will review the existing literature on MRD and its utility in the management of CLL. We will review the definitions of MRD, review MRD detection methods, and discuss the use of MRD in the current CLL treatment landscape. In doing so, we will clarify the present and conceivable future roles of MRD for the treatment of CLL. Conclusions: MRD is a powerful tool to assess response to CLL therapies, and can be prognostic with certain treatment regimens, such as fixed-duration venetoclax-based treatment. While we do not recommend MRD testing in routine clinical practice, we believe it has an important role in assessing treatment response and will be utilized routinely in the future. Further studies to incorporate MRD into treatment strategies for CLL are ongoing and will help to inform how we utilize it in clinical practice.

Prognostic factors in chronic lymphocytic leukaemia - the old, the new and the future

Prognostic assessment in chronic lymphocytic leukemia (CLL) is essential for delivery of timely, personalized therapy. TP53 status, karyotype, IGHV mutational status, minimal residual disease (MRD), gene mutations and markers of cell proliferation were important prognostic tools in the era of chemo-immunotherapy (CIT). With BCL2 inhibitors (BCL2i), outcome is still impacted by IGHV status, TP53 status, complex karyotype, and achievement of undetectable MRD. On the other hand, BTK inhibitors (BTKi) are agnostic to IGHV status, rarely cause MRD negative remissions and are less clearly impacted by TP53 status. Although based on less mature data, outcomes with BCL2i/BTKi combinations are likely influenced by TP53 and IGHV status. Responses to non-covalent BTKI (ncBTKI) are impacted by the mechanism of resistance to previous covalent BTKi. Finally, responses to chimeric antigen receptor T cell therapy (CAR-T) appear independent of TP53 status, but dependent on overall T- cell fitness.

The challenge of targeting key drivers of CLL and sequencing therapy in an era of experimental therapeutics

Treatment of chronic lymphocytic leukemia (CLL) has been revolutionized with the introduction of small molecule inhibitors targeting both the B-cell receptor (BCR) signaling pathway and B-cell lymphoma-2 (BCL-2) family of proteins. Inhibitors of Bruton's tyrosine kinase (BTK) and the BH3 mimetic venetoclax are bothcurrently used as the standard of care for patients in the frontline and relapsed/refractory setting of CLL. With the clinical success of both these classes of therapies, sequencing of these agents has become a major challenge in treatment of CLL. In this review we will discuss the current data available for both classes of agents in the front-line and relapsed/refractor setting, considerations when giving these agents, and how we can continue to improve the treatment landscape for CLL.

Real-world outcomes after discontinuation of covalent BTK inhibitor-based therapy in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma

This study described real-world treatment patterns and outcomes among patients with CLL/SLL in the post-cBTKi setting. Included were patients who received at least one cBTKi and subsequent line of therapy (LOT) within the Flatiron Health nationwide electronic health record-derived de-identified database (FHD; N = 1,479) and Optum's de-identified Clinformatics® Data Mart Database (CDM; N = 1,020). Frequently observed post-cBTKi treatments in both databases included cBTKi monotherapy (23-30%), anti-CD20 mab monotherapy (∼10%), BCL2i monotherapy (∼9%), BCL2i + anti-CD20 mab (∼9%), cBTKi + BCL2i (∼3%), and cBTKi + anti-CD20 mab (5-7%). From start of immediate LOT following cBTKi discontinuation, median time-to-treatment-discontinuation ranged across databases between 6 and 9 months; median time-to-next-treatment and median overall survival ranged between 18-23 months and 36-57 months, respectively. Observed heterogeneity in treatment patterns and outcomes in two cohorts of patients with CLL/SLL suggests lack of clarity in clinical evidence for treatment choice, and there remains a need for treatment options that deliver improved outcomes in the post-cBTKi setting.

Consensus recommendations from the 2024 Lymphoma Research Foundation workshop on treatment selection and sequencing in CLL or SLL

ABSTRACT

Over the past decade, treatment recommendations for patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) have shifted from traditional chemoimmunotherapy to targeted therapies. Multiple new therapies are commercially available, and, in many cases, a lack of randomized clinical trial data makes selection of the optimal treatment for each patient challenging. Additionally, many patients continue to receive chemoimmunotherapy in the United States, suggesting a gap between guidelines and real-world practice. The Lymphoma Research Foundation convened a workshop comprising a panel of CLL/SLL experts in the United States to develop consensus recommendations for selection and sequencing of therapies for patients with CLL/SLL in the United States. Herein, the recommendations are compiled for use as a practical clinical guide for treating providers caring for patients with CLL/SLL, which complement existing guidelines by providing a nuanced discussion relating how our panel of CLL/SLL experts in the United States care for patients in a real-world environment.

Evidence-based investigation of the efficacy and safety of venetoclax-containing regimens versus chemoimmunotherapy in chronic lymphocytic leukemia

Randomized controlled trials (RCTs) comparing the treatment outcomes and adverse events of venetoclax-containing regimens with chemoimmunotherapy in chronic lymphocytic leukemia (CLL) are scarce, and the available data are heterogeneous. We carried out a meta-analysis and systematic review to explore the efficacy and safety of these novel venetoclax combination therapies in CLL patients. Five RCTs (11 articles) involving 2481 CLL patients were included. Through a detailed pooled odds ratio analysis, it was revealed that, in terms of 1-year to 5-year progression-free survival (PFS) and overall survival (OS), venetoclax combination therapy demonstrated an obvious superiority over chemoimmunotherapy. In patients with unmutated immunoglobulin heavy chain variable region gene (IGHV), the 1-year to 5-year PFS was notably better with venetoclax combination therapy. In those with mutated IGHV, the 1-year to 4-year PFS was also improved with the use of venetoclax-containing regimens, although the 5-year PFS was comparable between the two treatment regimens. In patients with del(17p) and/or TP53 mutations, the 2-year, 3-year, and 4-year PFS were significantly superior with venetoclax-containing regimens. There were no significant differences between venetoclax-containing regimens and chemoimmunotherapy in all grade 3 or 4 adverse events, neutropenia, thrombocytopenia, infections, pneumonia, sepsis, infusion-related reactions, or tumor lysis syndrome. Venetoclax-containing regimens were associated with a decreased risk of anemia, leukopenia, febrile neutropenia, and pyrexia, but an increased risk of diarrhea and hypertension. Our results demonstrate the superiority of venetoclax-containing regimens in CLL patients, particularly in those with unmutated IGHV and del(17p) and/or TP53 mutations.

Chimeric Antigen Receptor-T Cells in the Modern Era of Chronic Lymphocytic Leukemia Treatment

Pathway inhibitors targeting Bruton tyrosine kinase (BTK) and B-cell lymphoma-2 (BCL-2) have dramatically changed the treatment landscape for both treatment-naïve and relapsed/refractory chronic lymphocytic leukemia (CLL). However, with increased utilization, a growing number of patients will experience progressive disease on both agents. This subgroup of "double refractory" patients has limited treatment options and poor prognosis. Chimeric antigen receptor (CAR)-T cells have transformed the treatment of relapsed/refractory B-cell malignancies. Although the earliest success of CAR-T cell therapy was in CLL, the clinical application of this modality has lagged until the recent approval of the first CAR-T cell product for CLL. In this review, we describe the current treatment options for upfront and subsequent therapies and the unmet need for novel agents highlighted by the burgeoning role and challenges of CAR-T cell therapy.

Molecular Composition and Kinetics of B Cells During Ibrutinib Treatment in Patients with Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of B cells due to constitutive B-cell receptor (BCR) signaling, leading to apoptosis resistance and increased proliferation. This study evaluates the effects of the Bruton Tyrosine Kinase (BTK) inhibitor ibrutinib on the molecular composition, clonality, and kinetics of B cells during treatment in CLL patients. Employing a multi-omics approach of up to 3.2 years of follow-up, we analyzed data from 24 CLL patients, specifically focusing on nine patients treated with ibrutinib monotherapy. In this study, clonal stability was observed within the ibrutinib-treated group following an effective initial clinical response, where clonotype frequencies of residual CLL cells remained high and stable, ranging from 74.9% at 1.5 years to 87.7% at approximately 3 years. In contrast, patients treated with the B-cell lymphoma 2 (BCL2) inhibitor venetoclax exhibited substantial reductions in clonal frequencies, approaching molecular eradication. Deep whole-exome sequencing revealed minimal genomic progression in the ibrutinib group, maintaining somatic drivers and variant allele frequencies (VAF) above 0.2 throughout treatment. At the single-cell level, the NF-κB pathway inhibition and apoptotic signals were detected or even augmented during treatment in ibrutinib-treated patients. These findings may corroborate the role of ibrutinib in stabilizing the genomic landscape of CLL cells, preventing significant genomic evolution despite maintaining a high clonal burden within the residual B-cell compartment.

BCL2i-Based Therapies and Emerging Resistance in Chronic Lymphocytic Leukemia

Overexpression of the anti-apoptotic protein BCL-2 is a key factor in the pathogenesis of chronic lymphocytic leukemia (CLL) and is associated with poor clinical outcomes. Therapeutic activation of apoptosis in cancer cells using the BCL-2 inhibitor (BCL2i) venetoclax has shown remarkable efficacy in clinical trials, both as monotherapy and combination regimens. However, patients with CLL experience a highly variable clinical course, facing significant challenges in advanced stages due to disease relapse and the emergence of resistant clones. Resistance mechanisms include acquired BCL-2 mutations, alteration of pro-apoptotic and anti-apoptotic proteins, metabolic reprogramming, epigenetic changes, and aberrant signaling pathways. To address this complex disease and improve progression-free survival, strategies targeting multiple signaling pathways and mechanisms have been explored. Randomized clinical trials of venetoclax in combination with Bruton tyrosine kinase (BTK) inhibitors or CD20 monoclonal antibodies have significantly outperformed traditional chemoimmunotherapy in both treatment-naïve and relapsed patients, achieving undetectable minimal residual disease (uMRD) and durable remissions. This review explores the intricate balance between BCL-2 family proteins and their role in the intrinsic apoptosis pathway, discusses venetoclax resistance mechanisms, and highlights the evolving role of venetoclax and other BCL2i-based combination therapies in CLL treatment.

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.

Immunophenotyping of Peripheral Blood Cells in Patients with Chronic Lymphocytic Leukemia Treated with Ibrutinib

Chronic lymphocytic leukemia (CLL) is a B-cell-derived hematologic malignancy whose progression depends on active B-cell receptor (BCR) signaling. Despite the spectacular efficacy of Ibrutinib, an irreversible inhibitor of Bruton tyrosine kinase (BTK), resistance can develop in CLL patients, and alternative therapeutic strategies are therefore required. Cancer immunotherapy has revolutionized cancer care and may be an attractive approach in this context. We speculated that characterizing the immune responses of CLL patients may highlight putative immunotherapeutic targets. Here, we used high-dimensional spectral flow cytometry to compare the distribution and phenotype of non-B-cell immune populations in the circulating blood of CLL patients treated with Ibrutinib displaying a complete response or secondary progression. Although no drastic changes were observed in the composition of their immune subsets, the Ibrutinib-resistant group showed increased cycling of CD8+ T cells, leading to their overabundance at the expense of dendritic cells. In addition, the expression of 11 different surface checkpoints was similar regardless of response status. Together, this suggests that CLL relapse upon Ibrutinib treatment may not lead to major alterations in the peripheral immune response.

Integrative Analysis of Multi-Omics Data to Identify Deregulated Molecular Pathways and Druggable Targets in Chronic Lymphocytic Leukemia

Chronic Lymphocytic Leukemia (CLL) is the most common B-cell malignancy in the Western world, characterized by frequent relapses despite temporary remissions. Our study integrated publicly available proteomic, transcriptomic, and patient survival datasets to identify key differences between healthy and CLL samples. We exposed approximately 1000 proteins that differentiate healthy from cancerous cells, with 608 upregulated and 415 downregulated in CLL cases. Notable upregulated proteins include YEATS2 (an epigenetic regulator), PIGR (Polymeric immunoglobulin receptor), and SNRPA (a splicing factor), which may serve as prognostic biomarkers for this disease. Key pathways implicated in CLL progression involve RNA processing, stress resistance, and immune response deficits. Furthermore, we identified three existing drugs-Bosutinib, Vorinostat, and Panobinostat-for potential further investigation in drug repurposing in CLL. We also found limited correlation between transcriptomic and proteomic data, emphasizing the importance of proteomics in understanding gene expression regulation mechanisms. This generally known disparity highlights once again that mRNA levels do not accurately predict protein abundance due to many regulatory factors, such as protein degradation, post-transcriptional modifications, and differing rates of translation. These results demonstrate the value of integrating omics data to uncover deregulated proteins and pathways in cancer and suggest new therapeutic avenues for CLL.

Chronic Lymphocytic Leukemia: Prognostic Factors in the Era of Novel Drugs

Novel drugs have profoundly changed the outcomes in chronic lymphocytic leukemia (CLL) patients, and the traditional prognostic factors that were identified in the era of chemoimmunotherapy need to be validated in the context of these new targeted therapies. Currently, the most important prognostic genetic biomarkers are the immunoglobulin heavy chain variable (IGHV) mutational status, genetic aberrations including del(17p)/TP53 abnormalities, and the complex karyotype. In this review, we discuss the prognostic role of these genomic markers in relation to novel treatments. Moreover, we present and discuss new scoring systems that were elaborated and validated in the era of new drugs. In routine clinical practice, the application of an extensive genomic work-up with validated prognostic markers could improve the identification of "very high-risk" CLL patients who could benefit from novel, more effective targeted treatments.