Chronic Lymphocytic Leukemia Therapy Research Articles

Human serum albumin-based drug-free macromolecular therapeutics induce apoptosis in chronic lymphocytic leukemia patient cells by crosslinking of CD20 and/or CD38 receptors.

This study explores the efficacy of human serum albumin (HSA)-based Drug-Free Macromolecular Therapeutics (DFMT) in treating Chronic Lymphocytic Leukemia (CLL), a prevalent adult leukemia subtype. DFMT, a novel strategy, employs biomimetic crosslinking of CD20 and CD38 receptors on malignant B cells without the need for low molecular weight drugs. Apoptosis is initiated via a two-step process: i) Recognition of a bispecific engager, Fab' fragment conjugated with morpholino oligonucleotide (Fab'-MORF1), by a cell surface antigen; followed by ii) crosslinking of the MORF1-decorated cells with a multivalent effector, HSA holding multiple copies of complementary MORF2, HSA-(MORF2)x. Herein we evaluated the efficacy of HSA-based DFMT in the treatment of 56 samples isolated from patients diagnosed with CLL. Fab' fragments from Obinutuzumab (OBN) and Isatuximab (ISA) were employed in the synthesis of anti-CD20 (Fab'OBN-MORF1) and anti-CD38 (Fab'ISA-MORF1) bispecific engagers. The efficacy of DFMT was significantly influenced by the expression levels of CD20 and CD38 receptors. Dual-targeting DFMT strategies (CD20 + CD38) were more effective than single-target approaches, particularly in samples with elevated receptor expression. Pretreatment of patient cells with gemcitabine or ricolinostat markedly increased cell surface CD20 and CD38 expression, respectively. Apoptosis was effectively initiated in 62.5% of CD20-targeted samples and in 42.9% of CD38-targeted samples. Our findings demonstrate DFMT's potential in personalized CLL therapy. Further research is needed to validate these outcomes in a larger number of patient samples and to explore DFMT's applicability to other malignancies.

BET inhibition reforms the immune microenvironment and alleviates T cell dysfunction in chronic lymphocytic leukemia.

Redundant tumor microenvironment (TME) immunosuppressive mechanisms and epigenetic maintenance of terminal T cell exhaustion greatly hinder functional antitumor immune responses in chronic lymphocytic leukemia (CLL). Bromodomain and extraterminal (BET) proteins regulate key pathways contributing to CLL pathogenesis and TME interactions, including T cell function and differentiation. Herein, we report that blocking BET protein function alleviates immunosuppressive networks in the CLL TME and repairs inherent CLL T cell defects. The pan-BET inhibitor OPN-51107 reduced exhaustion-associated cell signatures resulting in improved T cell proliferation and effector function in the Eμ-TCL1 splenic TME. Following BET inhibition (BET-i), TME T cells coexpressed significantly fewer inhibitory receptors (IRs) (e.g., PD-1, CD160, CD244, LAG3, VISTA). Complementary results were witnessed in primary CLL cultures, wherein OPN-51107 exerted proinflammatory effects on T cells, regardless of leukemic cell burden. BET-i additionally promotes a progenitor T cell phenotype through reduced expression of transcription factors that maintain terminal differentiation and increased expression of TCF-1, at least in part through altered chromatin accessibility. Moreover, direct T cell effects of BET-i were unmatched by common targeted therapies in CLL. This study demonstrates the immunomodulatory action of BET-i on CLL T cells and supports the inclusion of BET inhibitors in the management of CLL to alleviate terminal T cell dysfunction and potentially enhance tumoricidal T cell activity.

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

BackgroundImpact 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).MethodsCLL 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.ResultsThe 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.ConclusionIn 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.

A Review of Resistance Mechanisms to Bruton's Kinase Inhibitors in Chronic Lymphocytic Leukemia.

Bruton's Tyrosine Kinase (BTK) inhibitors have become one of the most vital drugs in the therapy of chronic lymphocytic leukemia (CLL). Inactivation of BTK disrupts the B-cell antigen receptor (BCR) signaling pathway, which leads to the inhibition of the proliferation and survival of CLL cells. BTK inhibitors (BTKi) are established as leading drugs in the treatment of both treatment-naïve (TN) and relapsed or refractory (R/R) CLL. Furthermore, BTKi demonstrate outstanding efficacy in high-risk CLL, including patients with chromosome 17p deletion, TP53 mutations, and unmutated status of the immunoglobulin heavy-chain variable region (IGHV) gene. Ibrutinib is the first-in-class BTKi which has changed the treatment landscape of CLL. Over the last few years, novel, covalent (acalabrutinib, zanubrutinib), and non-covalent (pirtobrutinib) BTKi have been approved for the treatment of CLL. Unfortunately, continuous therapy with BTKi contributes to the acquisition of secondary resistance leading to clinical relapse. In recent years, it has been demonstrated that the predominant mechanisms of resistance to BTKi are mutations in BTK or phospholipase Cγ2 (PLCG2). Some differences in the mechanisms of resistance to covalent BTKi have been identified despite their similar mechanism of action. Moreover, novel mutations resulting in resistance to non-covalent BTKi have been recently suggested. This article summarizes the clinical efficacy and the latest data regarding resistance to all of the registered BTKi.

Phosphatidylserine and Tyro3-Axl-Mertk Receptor Tyrosine Kinase level detection in plasma and on plasma-derived extracellular vesicle surface in chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is a chronic lymphoproliferative disorder characterized by monoclonal B cell proliferation. Studies carried out in recent years suggest that extracellular vesicles (EVs) may be a potential biomarker in cancer. Tyro3-Axl-Mertk (TAM) Receptor Tyrosine Kinases (RTKs) and Phosphatidylserine (PS) have crucial roles in macrophage-mediated immune response under normal conditions. In the tumor microenvironment, these molecules contribute to immunosuppressive signals and prevent the formation of local and systemic antitumor immune responses. Based on this, we aimed to evaluate the amount of PS and TAM RTK in plasma and on the surface of EVs in CLL patients and healthy volunteers in this study. In this study, 25 CLL (11 F/14 M) patients in the Rai (O-I) stage, newly diagnosed or followed up without treatment, and 15 healthy volunteers (11 F/4 M) as a control group were included. For all samples, PS and TAM RTK levels were examined first in the plasma and then in the EVs obtained from the plasma. We detected a significant decrease in plasma PS, and TAM RTK levels in CLL patients compared to the control. Besides, we determined a significant increase in TAM RTK levels on the EV surface in CLL, except for PS. In conclusion, these receptor levels measured by ELISA in plasma may not be effective for the preliminary detection of CLL. However, especially TAM RTKs on the surface of EVs may be good biomarkers and potential targets for CLL therapies.

Linc01588 deletion inhibits the malignant biological characteristics of hydroquinone-induced leukemic cells via miR-9-5p/SIRT1

Leukemia caused by environmental chemical pollutants has attracted great attention, the malignant leukemic transformation model of TK6 cells induced by hydroquinone (HQ) has been previously found in our team. However, the type of leukemia corresponding to this malignant transformed cell line model needs further study and interpretation. Furthermore, the molecular mechanism of malignant proliferation of leukemic cells induced by HQ remains unclear. This study is the first to reveal the expression of aberrant genes in leukemic cells of HQ-induced malignant transformation, which may correspond to chronic lymphocytic leukemia (CLL). The expression of Linc01588, a long non-coding RNA (lncRNA), was significantly up-regulated in CLL patients and leukemic cell line model which previously described. After gain-of-function assays and loss-of-function assays, feeble cell viability, severe apoptotic phenotype and the increased secretion of TNF-α were easily observed in malignant leukemic TK6 cells with Linc01588 deletion after HQ intervention. The tumors derived from malignant TK6 cells with Linc01588 deletion inoculated subcutaneously in nude mice were smaller than controls. In CLL and its cell line model, the expression of Linc01588 and miR-9–5p, miR-9–5p and SIRT1 were negative correlation respectively in CLL and cell line model, while the expression of Linc01588 and SIRT1 were positive correlation. The dual-luciferase reporter assay showed that Linc01588 & miR-9–5p, miR-9–5p & SIRT1 could bind directly, respectively. Furthermore, knockdown of miR-9–5p successfully rescued the severe apoptotic phenotype and the increased secretion of TNF-α caused by the Linc01588 deletion, the deletion of Linc01588 in human CLL cell line MEC-2 could also inhibit malignant biological characteristics, and the phenotype caused by the deletion of Linc01588 could also be rescued after overexpression of SIRT1. Moreover, the regulation of SIRT1 expression in HQ19 cells by Linc01588 and miR-9–5 P may be related to the Akt/NF-κB pathway. In brief, Linc01588 deletion inhibits the malignant biological characteristics of HQ-induced leukemic cells via miR-9–5p/SIRT1, and it is a novel and hopeful clue for the clinical targeted therapy of CLL.

Challenges associated with the use of Bruton's tyrosine kinase inhibitors: A life‑saving therapy for chronic lymphocytic leukemia (Review)

Challenges associated with the use of Bruton's tyrosine kinase inhibitors: A life‑saving therapy for chronic lymphocytic leukemia (Review)

A decade of chronic lymphocytic leukaemia therapy in Germany: Real-world treatment patterns and outcomes (2010-2022).

Pharmacotherapy options for chronic lymphocytic leukaemia (CLL) have expanded significantly in recent years. These options include chemotherapy, chemoimmunotherapy and signalling pathway inhibitors. A notable shift in the treatment landscape began with the widespread adoption of ibrutinib in 2016. This analysis of claims data focuses on understanding how the use of novel therapies has evolved in clinical practice over the past decade in Germany. Anonymized claims data (2010-2022) from German statutory health insurance was used, covering patient demographics, treatments, and prescriptions. The study population included patients with two confirmed CLL diagnoses. Treatment patterns were analysed, and survival outcomes were compared using time-to-event analyses. In the analysed cohort of 2983 incident CLL patients, 1041 started first-line therapy between 2011 and 2022, with a median duration of 18 months from diagnosis to the first prescription. Chemoimmunotherapy, the predominant 1L therapy until 2019, decreased significantly, while targeted therapy usage increased from 3% in 2015 to 77% in 2022. Targeted therapies became dominant in patients receiving treatment for relapsed or refractory disease after 2016. Median treatment durations were: 122 days for chemo, 176 days for chemo-immuno, and 373 days for targeted therapy. The overall survival for patients diagnosed in or after 2016 was significantly better (hazard ratio 0.56, 95% confidence interval, 0.44-0.69)). The adoption of targeted therapies like ibrutinib and venetoclax has transformed CLL treatment in Germany, leading to improved patient outcomes. Additionally, we demonstrate successful adherence to evolving clinical guidelines.

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.

Abstract 3849: Frontline ibrutinib-based therapy enhances CART cell functions in patients with CLL: Analysis of the phase 3 randomized clinical trial ECOG-ACRIN E1912

Abstract Introduction: Despite the remarkable activity of CD19-directed chimeric antigen receptor T cell therapy (CART19), durable remissions remain low, especially in chronic lymphocytic leukemia (CLL). Ibrutinib is an oral irreversible inhibitor of Bruton’s tyrosine kinase and is a first line therapy for CLL. Preclinical and early clinical data indicate that ibrutinib plus CART19 may be synergistic through inhibition of IL2-inducible T cell kinase. To systematically study the effects of prior ibrutinib treatment on subsequent CART functions, we utilized blood samples from the pivotal clinical trial E1912 (NCT02048813). E1912 was a phase 3 randomized trial comparing treatment with ibrutinib/rituximab (IR) to fludarabine/cyclophosphamide/rituximab (FCR) in previously untreated patients with CLL, which led to the FDA approval of ibrutinib as a first-line therapy in CLL. Methods: We evaluated the ex vivo expansion and effector functions of T cells and CART19 generated from patients (n=12) with CLL progression following treatment with IR or FCR. We generated CART19 from longitudinal samples obtained at baseline (pretreatment), 6 months post-treatment, 12 months post-treatment, and disease progression. Isolated T cells were lentivirally transduced to express CD28- or 41BB-costimulated CAR19. To assess antigen specific killing and proliferation, untransduced T cells or CART19 were co-cultured at a 1:1 ratio with the CD19+ cell line, JeKo-1, as a surrogate for CLL cells. Results: Ex vivo T cell expansion increased from an average of 1.5-fold at baseline to 6.7-fold at 6 months, 11.6-fold at 12 months, and 16.9-fold at progression, following ibrutinib-based therapy (p = 0.02, 0.04, and 0.04, respectively). Improved T cell expansion was independent of disease burden (p = 0.89, 0.73, and 0.54 for expansion vs B cell count at 6 months, 12 months, and progression). T cell expansion significantly worsened following treatment with FCR-based therapy compared to ibrutinib-based therapy (0.6- vs 11.6-fold at 12 months and 0.9- vs 16.9-fold at progression; p = 0.031 and 0.039, respectively). Starting at 6 months post-IR, CART19 demonstrated improved antitumor activity and antigen-specific proliferation against JeKo-1. There was no significant difference in the expansion of 41BB- vs CD28-costimulated CART19 following ibrutinib treatment. However, 41BB-CART19 showed enhanced antigen-specific proliferation upon stimulation with JeKo-1 (p = 0.008, 0.02, and 0.02 at 6 months, 12 months, and progression). Conclusion: Our results indicate significant improvement in T cell expansion and CART19 cell functions in patients with CLL following frontline ibrutinib-based therapy, and worsening T cell functions after FCR treatment. Improvement in T cell functions is independent of malignant B cell eradication and is more significant in 41BB-costimulated CART19. Citation Format: Truc Ngoc Huynh, Victoria Wang, Tait Shanafelt, Elizabeth L. Siegler, Carli M. Stewart, Kun Yun, Long K. Mai, Olivia Sirpilla, James H. Girsch, Claudia Manriquez-Roman, Jennifer M. Feigin, Makena Rodriguez, Brooke L. Kimball, Hong Xia, Reona L. Sakemura, Ismail Can, Omar L. Gutierrez-Ruiz, Ekene J. Ogbodo, Erin E. Tapper, Lionel A. Fonkoua, Mehrdad T. Hefazi, Michael W. Ruff, Sameer Parikh, Neil E. Kay, Saad J. Kenderian. Frontline ibrutinib-based therapy enhances CART cell functions in patients with CLL: Analysis of the phase 3 randomized clinical trial ECOG-ACRIN E1912 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3849.

An unappreciated cell survival-independent role for BAFF initiating chronic lymphocytic leukemia.

Chronic Lymphocytic Leukemia (CLL) is characterized by the expansion of CD19+ CD5+ B cells but its origin remains debated. Mutated CLL may originate from post-germinal center B cells and unmutated CLL from CD5+ mature B cell precursors. Irrespective of precursor types, events initiating CLL remain unknown. The cytokines BAFF and APRIL each play a significant role in CLL cell survival and accumulation, but their involvement in disease initiation remains unclear. We generated novel CLL models lacking BAFF or APRIL. In vivo experiments were conducted to explore the impact of BAFF or APRIL loss on leukemia initiation, progression, and dissemination. Additionally, RNA-seq and quantitative real-time PCR were performed to unveil the transcriptomic signature influenced by BAFF in CLL. The direct role of BAFF in controlling the expression of tumor-promoting genes was further assessed in patient-derived primary CLL cells ex-vivo. Our findings demonstrate a crucial role for BAFF, but not APRIL, in the initiation and dissemination of CLL cells. In the absence of BAFF or its receptor BAFF-R, the TCL1 transgene only increases CLL cell numbers in the peritoneal cavity, without dissemination into the periphery. While BAFF binding to BAFF-R is dispensable for peritoneal CLL cell survival, it is necessary to activate a tumor-promoting gene program, potentially linked to CLL initiation and progression. This direct role of BAFF in controlling the expression of tumor-promoting genes was confirmed in patient-derived primary CLL cells ex-vivo. Our study, involving both mouse and human CLL cells, suggests that BAFF might initiate CLL through mechanisms independent of cell survival. Combining current CLL therapies with BAFF inhibition could offer a dual benefit by reducing peripheral tumor burden and suppressing transformed CLL cell output.

Combination of Ibrutinib and Venetoclax in the Therapy of Chronic Lymphocytic Leukemia: A Review of the Latest Data from Clinical Studies

New Bruton’s tyrosine kinase (BTK) inhibitors caused drastic modifications in the therapy of chronic lymphocytic leukemia (CLL). Ibrutinib, the first in its class BTK inhibitor, showed high efficacy in many clinical studies. However, the treatment with BTK inhibitors as monotherapy must not be discontinued. Ibrutinib monotherapy inevitably leads to BTK inhibitor resistance and severe adverse events, which often results in treatment failure. Inhibitor BCL-2 venetoclax combined with BTK inhibitor can increase the therapy efficacy due to the synergetic effect of these agents on different CLL cell populations. Combined therapy potentially providing fixed-duration treatment can yield deeper responses. The present review focuses on ibrutinib and venetoclax combination, summarizes the latest data from clinical studies, and deals with feasibility of combined therapy in terms of its efficacy and safety profile.

Эффективность ибрутиниба в первой линии терапии у пациентов из группы высокого риска и во второй, третьей линиях при резистентном течении хронического лимфоцитарного лейкоза

Risk stratification appears to be the most valid criterion in decision-making regarding optimal specific therapy in chronic lymphocytic leukemia (CLL). The CLL International Prognostic Index takes account of unfavorable cytogenetic abnormalities (del(17p)/del(11q) and/or TP53 gene mutations) as well as the mutation status of immunoglobulin heavy chain variable (IGHV) region genes. Unmutated V(H)-status is commonly associated with such prognostically unfavorable genetic markers as del(17p)/del(11q), trisomy 12, and TP53 mutation. The combination of unmutated V(H)-status with unfavorable karyotype abnormalities (del(17p)/del(11q)) negatively affects the prognosis and overall survival rate. Besides, in high-risk CLL, the efficacy of therapy is rather low, and the development of refractoriness is possible. Targeted therapy (Bruton tyrosine kinase inhibitors) both in first line and in resistant CLL considerably increases the probability of achieving long-term remission. The present paper provides the comparative analysis of clinical and hematological efficacy and tolerability of ibrutinib in first-line CLL therapy of high-risk patients as well as second- and third-line therapies of resistant CLL. Ibrutinib shows high efficacy and low toxicity. First-line ibrutinib treatment results in a faster response and effectively reduces the probability of CLL progression. Second- and third-line ibrutinib treatment allows to overcome CLL resistance without impairing patients’ quality of life.

Ибрутиниб в лечении хронического лимфолейкоза у пациентов старше 60 лет из групп высокого и очень высокого риска

Aim. To assess the efficacy and tolerability of ibrutinib in chronic lymphocytic leukemia (CLL) therapy for high- and very-high-risk patients over 60 years of age.
 Materials & Methods. The study enrolled 18 CLL patients aged 60 and older. The patients were stratified by age: group 1 included 10 patients aged 60–70 years (median age 64.5 years) and group 2 included 8 patients aged ≥ 71 years (median age 75.8 years); there was equal number of men and women. All patients were subjected to molecular genetic analysis to identify poor prognosis factors and determine the IGHV gene mutation status. The cytogenetic analysis revealed karyotypic abnormalities including 17p deletion in 3 female patients aged 60, 66, and 77 years, respectively. All the patients had CLL without mutation in IGHV genes. They received ibrutinib 420 mg/day per os as first- and second-line therapies.
 Results. All patients showed aggravated comorbidity. The median follow-up was 28 months (range 18–42 months) in age group 1 and 46 months (range 12–78 months) in group 2. In group 1, a complete remission in 2 patients with del(17p) and a partial remission (PR) in 3 patients were achieved. PR with lymphocytosis was reported in the rest of 5 patients treated with ibrutinib for 12 months. In group 2, PR with the management of autoimmune complications in 5 out of 8 patients and PR with lymphocytosis in 3 patients were reported. The drug was well tolerated in both groups. No signs of severe hematological toxicity were observed in either of them.
 Conclusion. The choice of ibrutinib for high- and very-high-risk CLL patients aged 60 and older appeared to be optimal. This is also proved by the ease of administration of oral capsules, high efficacy, absence of tumor lysis syndrome, good tolerability, and acceptable toxicity profile.

Maintenance therapy for chronic lymphocytic leukaemia.

Maintenance therapy for chronic lymphocytic leukaemia.

Five-year follow-up of a phase 2 study of ibrutinib plus fludarabine, cyclophosphamide, and rituximab as initial therapy in CLL

AbstractWe previously reported high rates of undetectable minimal residual disease <10−4 (uMRD4) with ibrutinib plus fludarabine, cyclophosphamide, and rituximab (iFCR) followed by 2-year ibrutinib maintenance (I-M) in treatment-naïve chronic lymphocytic leukemia (CLL). Here, we report updated data from this phase 2 study with a median follow-up of 63 months. Of 85 patients enrolled, including 5 (6%) with deletion 17p or TP53 mutation, 91% completed iFCR and 2-year I-M. Five-year progression-free survival (PFS) and overall survival were 94% (95% confidence interval [CI], 89%-100%) and 99% (95% CI, 96%-100%), respectively. No additional deaths have occurred with this extended follow-up. No difference in PFS was observed by immunoglobulin heavy-chain variable region gene status or duration of I-M. High rates of peripheral blood (PB) uMRD4 were maintained (72% at the end of iFCR, 66% at the end of 2-year I-M, and 44% at 4.5 years from treatment initiation). Thirteen patients developed MRD conversion without clinical progression, mostly (77%) after stopping ibrutinib. None had Bruton tyrosine kinase (BTK) mutations. One patient had PLCG2 mutation. Six of these patients underwent ibrutinib retreatment per protocol. Median time on ibrutinib retreatment was 34 months. The cumulative incidence of atrial fibrillation was 8%. Second malignancy or nonmalignant hematologic disease occurred in 13%, mostly nonmelanoma skin cancer. Overall, iFCR with 2-year I-M achieved durably deep responses in patients with diverse CLL genetic markers. Re-emergent clones lacked BTK mutation and retained sensitivity to ibrutinib upon retreatment. This trial is registered at www.clinicaltrials.gov as #NCT02251548.

Chronic Lymphocytic Leukemia Therapy Guided by Measurable Residual Disease

BackgroundThe 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.MethodsIn 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.ResultsA 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%).ConclusionsMRD-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.)

Overcoming Resistance in Chronic Lymphocytic Leukemia-Maybe Less Is More?

Acquired mutations in BTK, PLCG2, and BCL2 are associated with resistance to continuous targeted agent therapy in chronic lymphocytic leukemia (CLL). Here, we discuss new evidence that limiting the duration of CLL therapy may prevent the evolution of such resistance mutations, potentially facilitating effective retreatment strategies. See related article by Jain et al., p. 498.

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.

Racial and Socioeconomic Disparities Among Patients with Chronic Lymphocytic Leukemia (CLL) Treated in the US Community Oncology Setting

Background: Since the first targeted therapy for CLL was approved by the Food and Drug Administration in 2014, new therapies and clinical practices have improved the care for patients with CLL. There is increased attention to racial disparities in healthcare. Objectives: To describe characteristics and outcomes of patients with CLL and assess whether there is equitable benefit from contemporary CLL therapies across racial and socioeconomic groups by analyzing real-world data collected in a large community oncology setting in the US. Methods: Patients with CLL treated in the US Oncology Network (The Network) from January 2015 through June 2023 were included. Data were sourced from structured data fields in iKnowMed™ (iKM), an oncology-specific electronic health record (EHR) system that captures outpatient practice encounters, including data on demographic and relevant clinical information for nearly 40% of US community oncology practices. iKM records are updated daily, and deterministically linked to supplementary Datavant mortality data and social determinants of health (SDoH) EHR data. Kaplan-Meier methods, univariate and multivariable cox regression were used to analyze overall survival (OS) and to determine the adjusted hazard ratio (HR) of OS. Considering that estimating the OS from initial diagnosis date is subject to immortal time bias, we performed the following two analyses: (1) time from the first visit date at a Network practice on or after the diagnosis date to OS, and (2) time from the initial diagnosis date among those newly diagnosed patients. In the primary analysis of OS, patients without a death date were censored at their last visit at The Network. In a sensitivity analysis, all follow-up data were censored at July 1, 2023. Results: The study included 12,253 CLL patients across all 4 census regions in the US, 60% were male. Of the 10,521 (86%) patients with race reported, 91.0% were white, 5.1% Black, and 3.9% were Other race. The median (Q1, Q3) age was 69 (61, 76) with Black patients 1.2 years younger than White patients (median: 69.0 versus 67.8, P=0.004). The initial CLL diagnosis was available for 11,576 (94%) patients and the majority (6,874; 59%) either had their initial diagnosis in The Network or had their first visit in The Network within 30 days after their initial diagnosis elsewhere. The median time from initial diagnosis to the first visit in The Network was slightly shorter for Black patients (2.4 weeks) as compared to White (3.9 weeks, p=0.001). At the initial diagnosis, more Black patients had Rai Stage III or IV than White patients (54% versus 46%, P=0.002). Death dates were available for 2,231 (18%) of patients. The analysis of time from first visit to death showed that the 8-year death rate was significantly higher for Black patients (61%) than White patients (43%, P=0.002) with statistically significant HR (95% confidence interval [CI]) of 1.34 (1.11, 1.61), P=0.002 in the univariate analysis. The median (95% CI) OS was 7.5 (6.4, not estimable) years for Black patients. The median OS was not estimable for White patients for this study because the study was designed to use data in the last 8 years and the median survival for White patients was longer than 8 years. After adjusting for education level and income, the race effect was no longer significant 1.25 (0.76, 2.05), P=0.37. The wider CI was due to SDoH data being only available for 2,928 (24%) of patients. Even with reduced statistical power, income of &amp;lt;$30k was significantly associated with higher risk of a shorter time to death with HR (95% CI) of 1.78 (1.32, 2.41), P&amp;lt;0.001 as compared to &amp;gt;$75k in the adjusted model. The analysis of time from the initial diagnosis date to OS among those newly diagnosed patients and the sensitivity analyses showed similar trends. Conclusion: This study identifies racial disparities in this modern era of CLL therapy using real-world data from a large community setting in the US. Black race and low income are prognostic of less favorable OS in CLL. Further research is needed to determine whether racial and income disparities in CLL are due to differences in access to therapy, quality of care, disease biology, comorbidities or other factors. This research may contribute to developing interventions to ensure that progress in CLL therapy benefits all patients.