Cytogenetic complexity in chronic lymphocytic leukemia: definitions, associations, and clinical impact

Allogeneic hematopoietic cell transplantation after prior targeted therapy for high-risk chronic lymphocytic leukemia

Allogeneic hematopoietic cell transplantation (alloHCT) can cure previously treated high-risk chronic lymphocytic leukemia (CLL) patients if they are suitable for transplant through the graft-versus-leukemia effect. However, since the emergence of targeted therapies, the role of alloHCT for high-risk CLL is less clear. To address this question, we evaluated 108 high-risk CLL patients who underwent alloHCT from 2010 to 2018. Thirty patients from the period of 2013 to 2018 received targeted therapy prior to alloHCT. The median age for the targeted therapy cohort was 60 years (range, 30-71 years), and 20% and 73% had complete and partial remission, respectively: 76% had del(17p), 46.2% had 5 or more cytogenetic abnormalities, and 78.9% were IGHV unmutated. The median number of prior therapies was 4 (range, 1-9). With a median follow-up time of 36 months (range, 10-72 months), the 3-year overall (OS) and progression-free survival (PFS) were 87% and 69%, respectively. The 3-year cumulative incidence of nonrelapse mortality and relapse was 7% and 24%, respectively. For the control cohort of 78 patients who underwent alloHCT from 2010 to 2014 and received only chemoimmunotherapy prior to transplant, the 3-year OS and PFS were 69% and 58%, respectively. Patients treated with targeted therapy prior to alloHCT had a significantly higher number of circulating T and B cells and a lower ratio of CD4 regulatory T cells to CD4 conventional T cells early after transplant. In summary, despite multiple high-risk features, the clinical outcome of CLL patients who receive targeted therapy prior to transplant is excellent and alloHCT should be offered while the disease is under control.

Analytical and clinical performance of chromosomal microarrays compared with FISH panel and conventional karyotyping in patients with chronic lymphocytic leukemia

In this single center retrospective analysis on 102 CLL patients, we assessed analytical and clinical performance of CMA against a targeted FISH panel (ATM, TP53, CEP12, D13S319 and LAMP1 loci) and karyotyping. CMA yielded additional information compared to karyotype in 39 cases (38 %). On the other hand, while CMA detected aberrations were also detected by FISH in all 31 cases (30 %), aberrations with low clonal size (<30 %) detected by FISH were missed by CMA. When evaluated with National Cancer Center Network (NCCN) guidelines, the capture rate of prognostic relevant cytogenetic information for FISH only, FISH + Chromosomes and FISH + CMA analyses were 95, 96 and 100 % respectively. With Cancer Cytogenomics Consortium (CGC) Criteria, these figures for FISH only, FISH + Chromosomes and FISH + CMA were 88 %, 92 and 100 % respectively. In conclusion, CMA provides additional analytical information to FISH and karyotyping, but this information has a clinical utility only in a small number of patients. Limit of detection (LOD) issues preclude replacement of FISH by CMA, but CMA may be a viable alternative to karyotyping. Further research is warranted.

The Evolving Landscape of Chronic Lymphocytic Leukemia on Diagnosis, Prognosis and Treatment

The knowledge of chronic lymphocytic leukemia (CLL) has progressively deepened during the last forty years. Research activities and clinical studies have been remarkably fruitful in novel findings elucidating multiple aspects of the pathogenesis of the disease, improving CLL diagnosis, prognosis and treatment. Whereas the diagnostic criteria for CLL have not substantially changed over time, prognostication has experienced an expansion with the identification of new biological and genetic biomarkers. Thanks to next-generation sequencing (NGS), an unprecedented number of gene mutations were identified with potential prognostic and predictive value in the 2010s, although significant work on their validation is still required before they can be used in a routine clinical setting. In terms of treatment, there has been an impressive explosion of new approaches based on targeted therapies for CLL patients during the last decade. In this current chemotherapy-free era, BCR and BCL2 inhibitors have changed the management of CLL patients and clearly improved their prognosis and quality of life. In this review, we provide an overview of these novel advances, as well as point out questions that should be further addressed to continue improving the outcomes of patients.

Low-burden TP53 mutations in CLL: Clinical impact and clonal evolution within the context of different treatment options

Chronic lymphocytic leukemia (CLL) patients with TP53 mutations experience chemo-refractory disease and are therefore indicated for targeted therapy. However, the significance of low-burden TP53 mutations with <10% variant allele frequency (VAF) remains a matter of debate. Here we describe clonal evolution scenarios of low-burden TP53 mutations and analyzed their clinical impact in a "real-world" CLL cohort. TP53 status was assessed by targeted NGS in 511 patients entering first-line treatment with chemo/immunotherapy and 159 relapsed patients treated with targeted agents. Within the pre-therapy cohort, 16% of patients carried low-burden TP53 mutations (0.1-10% VAF). While their presence did not significantly shorten event-free survival after first-line therapy, it affected overall survival (OS). For a subgroup with TP53 mutations of 1-10% VAF, the impact on OS was only observed in patients with unmutated IGHV that had not received targeted therapy, as patients benefited from switching to targeted agents regardless of initial TP53 mutational status. Analysis of the clonal evolution of low-burden TP53 mutations showed that the highest expansion rates were associated with FCR in both first and second-line treatment (median VAF increase 14.8x and 11.8x, respectively) in contrast to treatment with less intense chemo/immunotherapy regimens (1.6x) and without treatment (0.8x). In the relapsed cohort, 33% of patients carried low-burden TP53 mutations, which did not expand significantly upon targeted treatment (median VAF change 1x). Sporadic cases of TP53-mut clonal shifts were connected with the development of resistance-associated mutations. Altogether, our data support the incorporation of low-burden TP53 variants in clinical decision-making.

Expression of BCL2 alternative proteins and association with outcome in CLL patients treated with venetoclax

Venetoclax, a BCL-2 inhibitor, is highly effective for the treatment of patients with chronic lymphocytic leukemia (CLL) and dependence on alternative proteins may result in resistance to BCL-2 inhibition. Patients with CLL treated with venetoclax as monotherapy at MD Anderson Cancer Center between 05/2012 and 01/2016 were included and pretreatment bone marrow was analyzed by immunohistochemistry (IHC) for BCL-W, BCL-XL, BCL2-A1 and MCL-1. Twenty-seven patients were included. BCL-W + and BCL-2A1+ was found in 15% and 7% of the patients, respectively. Both BCL-XL and MCL-1 were negative in all samples. A higher CR and longer PFS rates were observed in patients with BCL-W+ (p = .60, p = .46), BCL-2A1+ (p = .60, p = .29), and either BCL-W + or BCL-2A1+ (p = .33, p = .20), though not statistically significant. Pretreatment IHC expression of BCL-2 alternative proteins does not predict response to venetoclax in CLL, but may be a surrogate for an indolent biology. Sensitive techniques are needed to explore anti-apoptotic pathways.

From Biomarkers to Models in the Changing Landscape of Chronic Lymphocytic Leukemia: Evolve or Become Extinct

Simple Summary

Chronic lymphocytic leukemia (CLL) is characterized by a highly variable clinical course. Thus, predicting the outcome of patients with this disease is a topic of special interest. The rapidly changing treatment landscape of CLL has questioned the value of classical biomarkers and prognostic models. Herein we examine the current state-of-the-art of prognostic and predictive biomarkers in the setting of new oral targeted agents with special focus on the most controversial findings over the last years. We also discuss the available information on the role of “old” and “new” prognostic models in the era of oral small molecules.

Abstract

Chronic lymphocytic leukemia (CLL) is an extremely heterogeneous disease. With the advent of oral targeted agents (Tas) the treatment of CLL has undergone a revolution, which has been accompanied by an improvement in patient’s survival and quality of life. This paradigm shift also affects the value of prognostic and predictive biomarkers and prognostic models, most of them inherited from the chemoimmunotherapy era but with a different behavior with Tas. This review discusses: (i) the role of the most relevant prognostic and predictive biomarkers in the setting of Tas; and (ii) the validity of classic and new scoring systems in the context of Tas. In addition, a critical point of view about predictive biomarkers with special emphasis on 11q deletion, novel resistance mutations, TP53 abnormalities, IGHV mutational status, complex karyotype and NOTCH1 mutations is stated. We also go over prognostic models in early stage CLL such as IPS-E. Finally, we provide an overview of the applicability of the CLL-IPI for patients treated with Tas, as well as the emergence of new models, generated with data from patients treated with Tas.

Bioinformatic strategies for the analysis of genomic aberrations detected by targeted NGS panels with clinical application

Molecular profiling of tumor samples has acquired importance in cancer research, but currently also plays an important role in the clinical management of cancer patients. Rapid identification of genomic aberrations improves diagnosis, prognosis and effective therapy selection. This can be attributed mainly to the development of next-generation sequencing (NGS) methods, especially targeted DNA panels. Such panels enable a relatively inexpensive and rapid analysis of various aberrations with clinical impact specific to particular diagnoses. In this review, we discuss the experimental approaches and bioinformatic strategies available for the development of an NGS panel for a reliable analysis of selected biomarkers. Compliance with defined analytical steps is crucial to ensure accurate and reproducible results. In addition, a careful validation procedure has to be performed before the application of NGS targeted assays in routine clinical practice. With more focus on bioinformatics, we emphasize the need for thorough pipeline validation and management in relation to the particular experimental setting as an integral part of the NGS method establishment. A robust and reproducible bioinformatic analysis running on powerful machines is essential for proper detection of genomic variants in clinical settings since distinguishing between experimental noise and real biological variants is fundamental. This review summarizes state-of-the-art bioinformatic solutions for careful detection of the SNV/Indels and CNVs for targeted sequencing resulting in translation of sequencing data into clinically relevant information. Finally, we share our experience with the development of a custom targeted NGS panel for an integrated analysis of biomarkers in lymphoproliferative disorders.

The future of laboratory testing in chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is a malignant lymphoproliferative disorder characterised by the accumulation of dysfunctional B-lymphocytes in the blood and lymphoid tissues. It is a clonally complex disease with a high degree of both intra-tumoural and inter-patient heterogeneity. This variability leads to a wide range of clinical outcomes and highlights the critical need for accurate prognostic tests in CLL. With the advent of a range of new targeted agents for CLL in recent years, there is also a clinical need for improved predictive tests to therapy. This review of laboratory testing in CLL focuses on emerging technologies for prognostication including single nucleotide polymorphism microarray for karyotypic analysis, targeted next generation sequencing analysis of the immunoglobulin heavy chain variable region gene as well as genes recurrently mutated in the disease such as TP53, and detection of minimal residual disease.

T Cells in Chronic Lymphocytic Leukemia: A Two-Edged Sword

Chronic lymphocytic leukemia (CLL) is a malignancy of mature, antigen-experienced B lymphocytes. Despite great progress recently achieved in the management of CLL, the disease remains incurable, underscoring the need for further investigation into the underlying pathophysiology. Microenvironmental crosstalk has an established role in CLL pathogenesis and progression. Indeed, the malignant CLL cells are strongly dependent on interactions with other immune and non-immune cell populations that shape a highly orchestrated network, the tumor microenvironment (TME). The composition of the TME, as well as the bidirectional interactions between the malignant clone and the microenvironmental elements have been linked to disease heterogeneity. Mounting evidence implicates T cells present in the TME in the natural history of the CLL as well as in the establishment of certain CLL hallmarks e.g. tumor evasion and immune suppression. CLL is characterized by restrictions in the T cell receptor gene repertoire, T cell oligoclonal expansions, as well as shared T cell receptor clonotypes amongst patients, strongly alluding to selection by restricted antigenic elements of as yet undisclosed identity. Further, the T cells in CLL exhibit a distinctive phenotype with features of “exhaustion” likely as a result of chronic antigenic stimulation. This might be relevant to the fact that, despite increased numbers of oligoclonal T cells in the periphery, these cells are incapable of mounting effective anti-tumor immune responses, a feature perhaps also linked with the elevated numbers of T regulatory subpopulations. Alterations of T cell gene expression profile are associated with defects in both the cytoskeleton and immune synapse formation, and are generally induced by direct contact with the malignant clone. That said, these abnormalities appear to be reversible, which is why therapies targeting the T cell compartment represent a reasonable therapeutic option in CLL. Indeed, novel strategies, including CAR T cell immunotherapy, immune checkpoint blockade and immunomodulation, have come to the spotlight in an attempt to restore the functionality of T cells and enhance targeted cytotoxic activity against the malignant clone.

Incorporating molecular biomarkers into the continuum of care in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a mature B-cell malignancy characterized by marked heterogeneity. Discoveries in disease biology over the past two decades have helped explain clinical variability and heralded the arrival of the targeted therapy era. In this article, we review improvements in risk stratification which have coincided with this progress, including individual biomarkers and their incorporation into prognostic models. Amidst an ever-expanding list of biomarkers, we seek to bring focus to the essential tests to improve patient care and counseling at particular times in the disease course, beginning with prognosis at diagnosis. The majority of patients do not require treatment at the time of diagnosis, making time-to-first-treatment a key initial prognostic concern. Prognostic and predictive biomarkers are then considered at subsequent major junctures, including at the time of treatment initiation, while on therapy, and at the time of relapse on novel agents.

Genomic arrays identify high-risk chronic lymphocytic leukemia with genomic complexity: a multi-center study

Complex karyotype (CK) identified by chromosome-banding analysis (CBA) has shown prognostic value in chronic lymphocytic leukemia (CLL). Genomic arrays offer high-resolution genome-wide detection of copy-number alterations (CNAs) and could therefore be well equipped to detect the presence of a CK. Current knowledge on genomic arrays in CLL is based on outcomes of single center studies, in which different cutoffs for CNA calling were used. To further determine the clinical utility of genomic arrays for CNA assessment in CLL diagnostics, we retrospectively analyzed 2293 arrays from 13 diagnostic laboratories according to established standards. CNAs were found outside regions captured by CLL FISH probes in 34% of patients, and several of them including gains of 8q, deletions of 9p and 18p (p<0.01) were linked to poor outcome after correction for multiple testing. Patients (n=972) could be divided in three distinct prognostic subgroups based on the number of CNAs. Only high genomic complexity (high-GC), defined as ≥5 CNAs emerged as an independent adverse prognosticator on multivariable analysis for time to first treatment (Hazard ratio: 2.15, 95% CI: 1.36-3.41; p=0.001) and overall survival (Hazard ratio: 2.54, 95% CI: 1.54-4.17; p<0.001; n=528). Lowering the size cutoff to 1 Mb in 647 patients did not significantly improve risk assessment. Genomic arrays detected more chromosomal abnormalities and performed at least as well in terms of risk stratification compared to simultaneous chromosome banding analysis as determined in 122 patients. Our findings highlight genomic array as an accurate tool for CLL risk stratification.

Case Report: Chronic Lymphocytic Leukemia With a Rare Translocation t(14;19)(q32;q13) Involving IGH/BCL3 Rearrangements: Report of Three Chinese Cases and Literature Review

Background

A translocation t(14;19)(q32;q13) leading to a fusion of IGH and BCL3 which is a rare cytogenetic abnormality in CLL patients, has a more aggressive clinical course with a shorter time to first treatment (TTT) and worse overall survival (OS). To date, there is no literature reporting the identification of the t(14;19) in Chinese CLL patients and the reviewing the characteristic of all patients with this abnormality reported previously in the literature.

Patients and Methods

We first demonstrate three cases of t(14;19) translocation among the 200 CLL patients from 2017 to 2019 in our hospital. We investigated several aspects such as clinicopathologic features, cytogenetic analysis, IGHV mutations, next-generation sequencing technology (NGS), and histopathological characteristics in order to clearly define the features of this entity in Chinese patients and compare them with patients reported previously in western countries.

Results

The clinical and pathological features of our three cases resemble those of earlier reports. All patients had atypical morphologic features and atypical immunophenotypes with low CLL scores detected by flow cytometry. All cases were unmutated in the IGHV mutations. Two cases showed complex karyotype and one case demonstrate missense mutations of TP53 and FBXW7.

Conclusion

In conclusion, this is the first report on IGH/BCL3-positive B-CLLs in Chinese people, which provided a comprehensive analysis of clinical and pathological characteristics. In addition to some similar clinical and laboratory features reported in the previous literature, we first found that CLL with t(14;19) has a higher possibility of being accompanied with high complex karyotype (high-CK), which is now regarded as a novel negative prognostic marker. Early identification of this abnormality in CLL patients is so important that patients can benefit from the more aggressive treatments at the onset of the disease.

Venetoclax Plus Rituximab in Relapsed Chronic Lymphocytic Leukemia: 4-Year Results and Evaluation of Impact of Genomic Complexity and Gene Mutations From the MURANO Phase III Study

PURPOSE

In previous analyses of the MURANO study, fixed-duration venetoclax plus rituximab (VenR) resulted in improved progression-free survival (PFS) compared with bendamustine plus rituximab (BR) in patients with relapsed or refractory chronic lymphocytic leukemia (CLL). At the 4-year follow-up, we report long-term outcomes, response to subsequent therapies, and the predictive value of molecular and genetic characteristics.

PATIENTS AND METHODS

Patients with CLL were randomly assigned to 2 years of venetoclax (VenR for the first six cycles) or six cycles of BR. PFS, overall survival (OS), peripheral-blood minimal residual disease (MRD) status, genomic complexity (GC), and gene mutations were assessed.

RESULTS

Of 389 patients, 194 were assigned to VenR and 195 to BR. Four-year PFS and OS rates were higher with VenR than BR, at 57.3% and 4.6% (hazard ratio [HR], 0.19; 95% CI, 0.14 to 0.25), and 85.3% and 66.8% (HR, 0.41; 95% CI, 0.26 to 0.65), respectively. Undetectable MRD (uMRD) at end of combination therapy (EOCT) was associated with superior PFS compared with low MRD positivity (HR, 0.50) and high MRD positivity (HR, 0.15). Patients in the VenR arm who received ibrutinib as their first therapy after progression (n = 12) had a reported response rate of 100% (10 of 10 evaluable patients); patients subsequently treated with a venetoclax-based regimen (n = 14) had a reported response rate of 55% (six of 11 evaluable patients). With VenR, the uMRD rate at end of treatment (EOT) was lower in patients with GC than in those without GC (P = .042); higher GC was associated with shorter PFS. Higher MRD positivity rates were seen with BIRC3 and BRAF mutations at EOCT and with TP53, NOTCH1, XPO1, and BRAF mutations at EOT.

CONCLUSION

Efficacy benefits with fixed-duration VenR are sustained and particularly durable in patients who achieve uMRD. Salvage therapy with ibrutinib after VenR achieved high response rates. Genetic mutations and GC affected MRD rates and PFS.

Incorporating acalabrutinib, a selective next-generation Bruton tyrosine kinase inhibitor, into clinical practice for the treatment of haematological malignancies

Greater understanding of the mechanisms involved in the disease progression of haematological malignancies has led to the introduction of novel targeted therapies with reduced toxicity compared with chemotherapy-based regimens, which has expanded the treatment options for patients with mantle cell lymphoma (MCL) and chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL). Ibrutinib is a first-in-class Bruton tyrosine kinase (BTK) inhibitor indicated for the treatment of patients with CLL/SLL or relapsed/refractory MCL. However, next-generation BTK inhibitors have been developed with improved specificity and the potential to reduce the off-target toxicity observed with ibrutinib. Acalabrutinib is a highly selective, next-generation BTK inhibitor, which was granted accelerated approval by the US Food and Drug Administration in 2017 for the treatment of adult patients with MCL who have received at least one prior therapy. In November 2019, it was also granted approval for the treatment of adult patients with CLL/SLL on the basis of two phase 3 clinical trials. This review describes the current understanding of acalabrutinib according to clinical study data for the treatment of MCL and CLL/SLL and shares recommendations from our practice on how it should be used when treating patients in the clinic, including dosing, administration and management of adverse events.

The complex karyotype and chronic lymphocytic leukemia: prognostic value and diagnostic recommendations

Chromosomal abnormalities are frequently observed in patients with chronic lymphocytic leukemia (CLL) and have prognostic value. Deletions of the short arm of chromosome 17 (and/or mutations TP53) predict resistance to chemoimmunotherapy and shorter progression-free survival after targeted therapies. Although the complex karyotype (CK) is strongly predictive of a poor prognosis in hematologic malignancies such acute myeloid leukemia or myelodysplastic syndrome, its value in CLL is subject to debate. Here, we review the literature on the CK in CLL and examine its prognostic value with different treatments. We also propose a standardized method for defining a CK in all types of hematopoietic neoplasm.

Time to first treatment and P53 dysfunction in chronic lymphocytic leukaemia: results of the O-CLL1 study in early stage patients

Chronic lymphocytic leukaemia (CLL) is characterised by a heterogeneous clinical course. Such heterogeneity is associated with a number of markers, including TP53 gene inactivation. While TP53 gene alterations determine resistance to chemotherapy, it is not clear whether they can influence early disease progression. To clarify this issue, TP53 mutations and deletions of the corresponding locus [del(17p)] were evaluated in 469 cases from the O-CLL1 observational study that recruited a cohort of clinically and molecularly characterised Binet stage A patients. Twenty-four cases harboured somatic TP53 mutations [accompanied by del(17p) in 9 cases], 2 patients had del(17p) only, and 5 patients had TP53 germ-line variants. While del(17p) with or without TP53 mutations was capable of significantly predicting the time to first treatment, a reliable measure of disease progression, TP53 mutations were not. This was true for cases with high or low variant allele frequency. The lack of predictive ability was independent of the functional features of the mutant P53 protein in terms of transactivation and dominant negative potential. TP53 mutations alone were more frequent in patients with mutated IGHV genes, whereas del(17p) was associated with the presence of adverse prognostic factors, including CD38 positivity, unmutated-IGHV gene status, and NOTCH1 mutations.

Prediction of Outcome in Patients With Chronic Lymphocytic Leukemia Treated With Ibrutinib: Development and Validation of a Four-Factor Prognostic Model

PURPOSE

Randomized trials established the superiority of ibrutinib-based therapy over chemoimmunotherapy in chronic lymphocytic leukemia. Durability of progression-free survival (PFS) with ibrutinib can vary by patient subgroup. Clinical tools for prognostication and risk-stratification are needed.

PATIENTS AND METHODS

Patients treated with ibrutinib in phase II and III trials provided the discovery data set and were subdivided into discovery and internal validation cohorts. An external validation cohort included 84 patients enrolled in our investigator-initiated phase II trial. Univariable analysis of 18 pretreatment parameters was performed using PFS and overall survival (OS) end-points. Multivariable analysis and machine-learning algorithms identified four factors for a prognostic model that was validated in internal and external cohorts.

RESULTS

Factors independently associated with inferior PFS and OS were as follows: TP53 aberration, prior treatment, β-2 microglobulin ≥ 5 mg/L, and lactate dehydrogenase > 250 U/L. Each of these four factors contributed one point to a prognostic model that stratified patients into three risk groups: three to four points, high risk; two points, intermediate risk; zero to one point, low risk. The 3-year PFS rates for all 804 patients combined were 47%, 74%, and 87% for the high-, the intermediate-, and the low-risk group, respectively (P < .0001). The 3-year OS rates were 63%, 83%, and 93%, respectively (P < .0001). The model remained significant when applied to treatment-naïve and relapsed/refractory cohorts individually. For 84 patients in the external cohort, BTK and PLCG2 mutations were tested cross-sectionally and at progression. The cumulative incidences of mutations were strongly correlated with the model. In the external cohort, Richter's transformation occurred in 17% of the high-risk group, and in no patient in the low-risk group.

CONCLUSION

Patients at increased risk of ibrutinib failure can be identified at treatment initiation and considered for clinical trials.

Diagnosis and Treatment of Chronic Lymphocytic Leukemia: Recommendations of the French CLL Study Group (FILO)

As a result of significant recent developments, the management of patients with chronic lymphocytic leukemia (CLL) is changing, and new therapeutic options will continue to emerge in the near future. The recommendations of the French Innovative Leukemia Organization (FILO-CLL) group presented here are intended to provide practical recommendations for physicians taking care of CLL patients, taking into account the availability of both biological tests and therapies in daily practice in France at the time of publication. This text details the documented information and guidelines on diagnosis, indications for treatment, infectious complications and therapeutic strategies in frontline and relapsed CLL as well as in particular conditions such as autoimmune cytopenia or Richter syndrome.

Recent progress of prognostic biomarkers and risk scoring systems in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most prevalent adult leukemia with high heterogeneity in the western world. Thus, investigators identified a number of prognostic biomarkers and scoring systems to guide treatment decisions and validated them in the context of immunochemotherapy. A better understanding of prognostic biomarkers, including serum markers, flow cytometry outcomes, IGHV mutation status, microRNAs, chromosome aberrations and gene mutations, have contributed to prognosis in CLL. Del17p/ TP53 mutation, NOTCH1 mutation, CD49d, IGHV mutation status, complex karyotypes and microRNAs were reported to be of predictive values to guide clinical decisions. Based on the biomarkers above, classic prognostic models, such as the Rai and Binet staging systems, MDACC nomogram, GCLLSG model and CLL-IPI, were developed to improve risk stratification and tailor treatment intensity. Considering the presence of novel agents, many investigators validated the conventional prognostic biomarkers in the setting of novel agents and only TP53 mutation status/del 17p and CD49d expression were reported to be of prognostic value. Whether other prognostic indicators and models can be used in the context of novel agents, further studies are required.

Chronic lymphocytic leukemia: from molecular pathogenesis to novel therapeutic strategies

Chronic lymphocytic leukemia is a well-defined lymphoid neoplasm with very heterogeneous biological and clinical behavior. The last decade has been remarkably fruitful in novel findings elucidating multiple aspects of the pathogenesis of the disease including mechanisms of genetic susceptibility, insights into the relevance of immunogenetic factors driving the disease, profiling of genomic alterations, epigenetic subtypes, global epigenomic tumor cell reprogramming, modulation of tumor cell and microenvironment interactions, and dynamics of clonal evolution from early steps in monoclonal B cell lymphocytosis to progression and transformation into diffuse large B-cell lymphoma. All this knowledge has offered new perspectives that are being exploited therapeutically with novel target agents and management strategies. In this review we provide an overview of these novel advances and highlight questions and perspectives that need further progress to translate into the clinics the biological knowledge and improve the outcome of the patients.

Low Humoral Immune Response and Ineffective Clearance of SARS-Cov-2 in a COVID-19 Patient With CLL During a 69-Day Follow-Up

Background: A recent outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2), which began in Wuhan, China, with a high level of human-to-human transmission has been reported. There are limited data available on Coronavirus Disease 2019 (COVID-19) patients with hematological malignancies with more than 60 days of follow-up. This study describes the clinical characteristics, including multiple recurrences of COVID-19, in a patient with chronic lymphocytic leukemia (CLL) during 69 days of follow-up.

Case Presentation: A 72-year-old female was admitted to hospital isolation after being infected with COVID-19 as part of a family cluster on January 30, 2020. Apart from SARS-Cov-2 virus infection, laboratory results revealed lymphocytosis of uncertain etiology and abnormal distribution of T lymphocytes. On blood smears, small blue lymphocytes with scant cytoplasm were observed, and the presence of high levels of circulating clonal B cells was also demonstrated by flow cytometry. The patient was diagnosed with COVID-19 and CLL. Among her family members, she had the highest viral loads and the fastest progression on lung injury and developed severe pneumonia. Serological results showed she had both 2019-nCoV-specific IgM and IgG antibodies; however, only IgG antibodies were detected in her husband's plasma.

Results: A combination regimen of antiviral therapy and high-dose intravenous immunoglobulin (IVIG) in the early stage seemed to be effective for treating CLL and SARS-Cov-2 infection. Because of the low humoral immune response, the CLL patient could not effectively clear the SARS-Cov-2 infection and suffered from recurrence twice during the 69-day follow-up.

Conclusion: In CLL, a neoplastic antigen-specific B-cell clone proliferates, and the progeny cells accumulate and outgrow other B cells, leading to immune deficiency. Considering the low humoral immune response and ineffective clearance of SARS-Cov-2 in CLL patients, the follow-up and home quarantine period should be extended. We need further studies to clarify suspending or continuing CLL therapy during COVID infection. For those patients who are prone to progression to severe disease, administering humoral immunity therapies can help to prevent disease progression and quickly meet the cure criteria.

TP53 dysfunction in chronic lymphocytic leukemia: clinical relevance in the era of B-cell receptors and BCL-2 inhibitors

INTRODUCTION

Patients with TP53 dysfunction, assessed by del(17p) or TP53 mutations, respond poorly to chemo-immunotherapy and fare better with the new therapies (BCR and BCL-2 inhibitors); however, it is unclear whether their response is similar to that of patients without anomalies or whether there is currently an adequate determination of TP53 dysfunction.

AREA COVERED

A literature search was undertaken on clinical trials and real-world experience data on patients with TP53 dysfunction treated with different protocols. Moreover, data on the TP53 biological function and on the tests currently employed for its assessment were reviewed.

EXPERT OPINION

Although TP53 dysfunction has less negative influence on the new biological therapies, patients with these alterations, particularly those with biallelic inactivation of TP53, have a worst outcome with these therapies than those without alterations. At present, a determination of TP53, particularly with next generation sequencing (NGS) methodologies, may be sufficient for the identifications of the patients unsuitable for chemo-immunotherapy, although integration with del(17p) would be advisable. For the future, more extensive determinations of the TP53 status, including functional assays, may become part of the current armamentarium for a better patient stratification and treatment with newer protocols.

In chronic lymphocytic leukaemia, SLAMF1 deregulation is associated with genomic complexity and independently predicts a worse outcome

In a series of 349 patients with chronic lymphocytic leukaemia (CLL), we found lower levels of signalling lymphocytic activation molecule family member 1 (SLAMF1) expression in cases with highly complex karyotypes, as defined by the presence of five or more chromosomal abnormalities (CK5; P < 0·001) and with major chromosomal structural abnormalities (P < 0·001). SLAMF1 downregulation was significantly associated with advanced Binet Stage (P = 0·001), CD38 positivity (P < 0·001), high β₂ -microglobulin levels (P < 0·001), immunoglobulin heavy chain variable region gene (IGHV) unmutated status (P < 0·001), 11q deletion (P < 0·001), tumour protein p53 (TP53) disruption (P = 0·011) and higher risk CLL International Prognostic Index categories (P < 0·001). Multivariate analysis showed that downregulated SLAMF1 levels had independent negative prognostic impact on time-to-first treatment (P < 0·001) and overall survival (P < 0·001).

Genomic and Epigenomic Alterations in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia is a common disease in Western countries and has heterogeneous clinical behavior. The relevance of the genetic basis of the disease has come to the forefront recently, with genome-wide studies that have provided a comprehensive view of structural variants, somatic mutations, and different layers of epigenetic changes. The mutational landscape is characterized by relatively common copy number alterations, a few mutated genes occurring in 10-15% of cases, and a large number of genes mutated in a small number of cases. The epigenomic profile has revealed a marked reprogramming of regulatory regions in tumor cells compared with normal B cells. All of these alterations are differentially distributed in clinical and biological subsets of the disease, indicating that they may underlie the heterogeneous evolution of the disease. These global studies are revealing the molecular complexity of chronic lymphocytic leukemia and provide new perspectives that have helped to understand its pathogenic mechanisms and improve the clinical management of patients.

Evolution in the management of chronic lymphocytic leukemia in Japan: should MRD negativity be the goal?

Advances in the molecular biology of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and development of molecularly targeted therapies have resulted in treatment innovations. Therapeutic approaches for previously untreated CLL/SLL patients are changing from chemoimmunotherapy (CIT) to molecularly targeted drugs. The aim of therapy for CLL patients has been to control the disease; however, FCR (fludarabine, cyclophosphamide, rituximab) has improved outcomes and reduced the high incidence of undetectable minimum/measurable residual disease (MRD) in previously untreated CLL patients with no 17p deletion/TP53 disruption and mutated immunoglobulin heavy chain gene (IGHV). Patients achieving undetectable MRD in the bone marrow are expected to be cured. BTK inhibitors and BCL-2 inhibitors are effective for CLL/SLL patients. However, atrial fibrillation and bleeding are associated with the BTK inhibitor, ibrutinib, while tumor lysis syndrome is an adverse event (AE) of the BCL-2 inhibitor, venetoclax. Although these novel targeted drugs are very useful, they are also expensive. Emergence of resistant clones of CLL cells must also be addressed. Therefore, treatments of indefinite duration until progression have been replaced by fixed-duration treatments. This review introduces advances in the treatment of previously untreated CLL/SLL patients in Europe and the United States.

BTK inhibitors and anti-CD20 monoclonal antibodies for treatment-naïve elderly patients with CLL

Older patients account for the majority of patients with chronic lymphocytic leukemia (CLL), and so strategies for managing CLL in this population is of upmost importance. Inhibition of Bruton’s tyrosine kinase (BTK) has been a successful therapeutic strategy in CLL, and the first-generation BTK inhibitor ibrutinib has been shown to be superior to standard chemoimmunotherapy in multiple studies specifically targeting older patients. A second-generation BTK inhibitor, acalabrutinib, has also been studied in CLL, and has recently been granted breakthrough designation by the United States Food and Drug Administration. One ongoing question is whether the addition of anti-CD20 monoclonal antibodies improve response or response durability with BTK inhibitors. In this review, we will discuss clinical trials of ibrutinib and acalabrutinib in older patients with CLL, and the possible contributions of anti-CD20 antibodies to these therapies.

Prognostic model for newly diagnosed CLL patients in Binet stage A: results of the multicenter, prospective CLL1 trial of the German CLL study group

The heterogeneity of early stage CLL challenges prognostication, and refinement of prognostic indices for risk-adapted management in this population is essential. The aim of the multicenter, prospective CLL1 trial was to explore a novel prognostic model (CLL1-PM) developed to identify risk groups, separating patients with favorable from others with dismal prognosis. A cohort of 539 clinically, biochemically, and genetically characterized Binet stage A patients were observed until progression, first-line treatment, or death. Multivariate analysis identified six independent factors associated with overall survival (OS) and time-to-first treatment (TTFT): del(17p), unmutated IGHV, del(11q), ß2-microglobulin >3.5 mg/dL, lymphocyte doubling time (LDT) <12 months, and age >60 years. These factors were integrated into the CLL1-PM, which stratified patients into four risk groups. The CLL1-PM was prognostic for OS and TTFT, e.g., the risk of treatment at 5 years was 85.9, 51.8, 27.6, and 11.3% for very low (0-1.5), low (2-4), high (4.5-6.5), and very high-risk (7-14) scores, respectively (P < 0.001). Notably, in addition to factors comprising CLL-IPI, we substantiated del(11q) and LDT as prognostic factors in early CLL. Altogether, our findings would be useful to effectively stratify Binet stage A patients, particularly within the scope of clinical trials evaluating novel agents.

Relapsed disease and aspects of undetectable MRD and treatment discontinuation

Continuous treatment vs fixed duration of monotherapies and combinations of targeted agents are treatment options in relapsed chronic lymphocytic leukemia. The optimal choice of relapse treatment is dependent on the prior frontline therapy, duration of remission after frontline, genetic markers, and patients' condition, including age and comorbidities. Combination therapies may result in deep responses with undetectable minimal residual disease (uMRD). Although uMRD is an excellent predictive marker for disease progression, it is rarely used in clinical practice and needs additional evaluation in clinical trials before discontinuation of therapy should be guided according to uMRD.

Association of gene mutations with time-to-first treatment in 384 treatment-naive chronic lymphocytic leukaemia patients

This study correlated somatic mutation results and known prognostic factors with time-to-first treatment (TTFT) in 384 treatment-naïve (TN) chronic lymphocytic leukaemia (CLL) patients to help determine disease-specific drivers of early untreated CLL. CLL DNA from either peripheral blood or bone marrow underwent next generation targeted sequencing with a 29-gene panel. Gene mutation data and concurrent clinical characteristics, such as Rai/Binet stage, fluorescence in situ hybridisation (FISH), ZAP70/CD38, karyotype and IGHV mutation, status were analysed in univariable and multivariable analyses to identify associations with TTFT. TTFT was defined as time from diagnosis to initial treatment. In univariable analyses, mutated ATM (P < 0·001), NOTCH1 (P < 0·001) and SF3B1 (P = 0·002) as well as unmutated IGHV (P < 0·001), del(11q) (P < 0·001) and trisomy 12 (P < 0·001) by hierarchal FISH and advanced Rai (P = 0·05) and Binet (P < 0·001) stages were associated with shorter TTFT. Importantly, del(17p), mutated TP53 and complex karyotype were not associated with shorter TTFT. In a reduced multivariable analysis, mutated ATM (P < 0·001) and unmutated IGHV status (P < 0·001) remained significant, showing their importance in early leukaemogenesis. High-risk prognostic markers such as del(17p), mutated TP53 and complex karyotype, were not correlated with TTFT, suggesting that these abnormalities have limited roles in early disease progression but are more important in relapsed CLL.

Sequential and combination treatments with novel agents in chronic lymphocytic leukemia

Chemoimmunotherapy has been the standard of care for patients with chronic lymphocytic leukemia for a long time. However, over the last few years, novel agents have produced unprecedented outcomes in treatment-naïve and relapsed/refractory chronic lymphocytic leukemia. With the advent of these targeted agents, treatment options have diversified very considerably and new questions have emerged. For example, it is unclear whether these novel agents should be used as sequential monotherapies until disease progression or whether they should preferably be combined in time-limited treatment regimens aimed at achieving deep and durable remissions. While both approaches yield high response rates and long progression-free and overall survival, it remains challenging to identify patients individually for the optimal concept. This review provides guidance in this decision process by presenting evidence on sequential and combined use of novel agents and discussing the advantages and drawbacks of these two approaches.

Cytogenetic landscape in 1012 newly diagnosed chronic lymphocytic leukemia

BACKGROUND

Chronic lymphocytic leukemia (CLL) stratification mainly relies on FISH markers according to Döhner's hierarchical model which includes high-risk FISH markers, intermediate FISH, or low-risk FISH. Recently, complex karyotype (CK) has been demonstrated as an independent negative prognostic factor in CLL.

METHODS

A series of 1012 untreated CLL patients have been investigated with both FISH and chromosome banding analysis (CBA) on the same pellet obtained from interleukin IL-2-CPG DSP30 oligonucleotide-stimulated cultured cells.

RESULTS

Combining both FISH and CBA has led to refine prognostic categories with identification of 30% of CK in low-risk and intermediate FISH group. This raises the issue of switching them to a high-risk group. While this series confirmed the significant association between CK and high-risk FISH (P = .003), 33% of CK present no ATM or TP53 deletion. Three groups characterized by significant association between FISH markers and CBA have emerged: CK with TP53 loss and monosomy 15; CK with ATM loss and 14q32 translocation; and CK without ATM or TP53 losses but trisomies 12, 18, and 19 or t(14;18)(q32;q21).

CONCLUSION

We have observed that in addition to FISH analysis, the CBA allows detection of many abnormalities with potential impact on patient follow-up and treatment, mainly CK.

Time-to-progression after front-line fludarabine, cyclophosphamide, and rituximab chemoimmunotherapy for chronic lymphocytic leukaemia: a retrospective, multicohort study

BACKGROUND

Fludarabine, cyclophosphamide, and rituximab (FCR) has become a gold-standard chemoimmunotherapy regimen for patients with chronic lymphocytic leukaemia. However, the question remains of how to treat treatment-naive patients with IGHV-unmutated chronic lymphocytic leukaemia. We therefore aimed to develop and validate a gene expression signature to identify which of these patients are likely to achieve durable remissions with FCR chemoimmunotherapy.

METHODS

We did a retrospective cohort study in two cohorts of treatment-naive patients (aged ≥18 years) with chronic lymphocytic leukaemia. The discovery and training cohort consisted of peripheral blood samples collected from patients treated at the University of Texas MD Anderson Cancer Center (Houston, TX, USA), who fulfilled the diagnostic criteria of the International Workshop on Chronic Lymphocytic Leukemia, had received at least three cycles of FCR chemoimmunotherapy, and had been treated between Oct 10, 2000, and Oct 26, 2006 (ie, the MDACC cohort). We did transcriptional profiling on samples obtained from the MDACC cohort to identify genes associated with time to progression. We did univariate Cox proportional hazards analyses and used significant genes to cluster IGHV-unmutated samples into two groups (intermediate prognosis and unfavourable prognosis). After using cross-validation to assess robustness, we applied the Lasso method to standardise the gene expression values to find a minimum gene signature. We validated this signature in an external cohort of treatment-naive patients with IGHV-unmutated chronic lymphocytic leukaemia enrolled on the CLL8 trial of the German Chronic Lymphocytic Leukaemia Study Group who were treated between July 21, 2003, and April 4, 2006 (ie, the CLL8 cohort).

FINDINGS

The MDACC cohort consisted of 101 patients and the CLL8 cohort consisted of 109 patients. Using the MDACC cohort, we identified and developed a 17-gene expression signature that distinguished IGHV-unmutated patients who were likely to achieve a long-term remission following front-line FCR chemoimmunotherapy from those who might benefit from alternative front-line regimens (hazard ratio 3·83, 95% CI 1·94-7·59; p<0·0001). We validated this gene signature in the CLL8 cohort; patients with an unfavourable prognosis versus those with an intermediate prognosis had a cause-specific hazard ratio of 1·90 (95% CI 1·18-3·06; p=0·008). Median time to progression was 39 months (IQR 22-69) for those with an unfavourable prognosis compared with 59 months (28-84) for those with an intermediate prognosis.

INTERPRETATION

We have developed a robust, reproducible 17-gene signature that identifies a subset of treatment-naive patients with IGHV-unmutated chronic lymphocytic leukaemia who might substantially benefit from treatment with FCR chemoimmunotherapy. We recommend testing the value of this gene signature in a prospective study that compares FCR treatment with newer alternative therapies as part of a randomised clinical trial.

FUNDING

Chronic Lymphocytic Leukaemia Global Research Foundation and the National Institutes of Health/National Cancer Institute.

Profiling of biological and environmental risk factors in immunogenetic subgroups of chronic lymphocytic leukemia - Czech national study

AIMS

This is a nation-wide survey of chronic lymphocytic leukemia (CLL) patients at six large hematology centers in the Czech Republic. The aim was to identify specific populations, social, and health characteristics of CLL subgroups divided according to the immunogenetic features of their B cell receptors (BCRs) and clonality.

PATIENTS AND METHODS

Questionnaires directed to specific health, social, and environmental conditions were collected in a cohort of 573 CLL patients. For these patients, immunoglobulin heavy chain gene rearrangements were also analyzed in order to gain information about their clonality, IGHV mutational status, and the presence of stereotyped BCRs. Data extracted from the questionnaires were analyzed statistically in the context of immunogenetic features of the cohort.

RESULTS

There were no statistically significant differences in the data collected in the survey between patients with mutated and patients with unmutated IGHV. However, patients with oligoclonal CLL reported health conditions such as hypercholesterolemia, hypertension, herpes simplex, tumors, and also, separately, CLL in 1^st degree relatives, more often than their monoclonal counterparts. In patients with stereotyped BCRs, we found more frequent alcohol consumption and gastric infections in subset #1 cases and frequent cholecystectomies and familial CLL in subset #2 cases.

CONCLUSION

To the best of our knowledge, this study is the first to investigate CLL immunogenetic features and clonality in the context of epidemiological data. We reported statistically significant associations suggesting the influence of certain health and social conditions on a number of clonal populations expanding in CLL and also on characteristic BCR features, especially stereotypy.

Genomic alterations in high-risk chronic lymphocytic leukemia frequently affect cell cycle key regulators and NOTCH1-regulated transcription

To identify genomic alterations contributing to the pathogenesis of high-risk chronic lymphocytic leukemia (CLL) beyond the well-established role of TP53 aberrations, we comprehensively analyzed 75 relapsed/refractory and 71 treatment-naïve high-risk cases from prospective clinical trials by single nucleotide polymorphism arrays and targeted next-generation sequencing. Increased genomic complexity was a hallmark of relapsed/refractory and treatment-naïve high-risk CLL. In relapsed/refractory cases previously exposed to the selective pressure of chemo(immuno)therapy, gain(8)(q24.21) and del(9)(p21.3) were particularly enriched. Both alterations affect key regulators of cell-cycle progression, namely MYC and CDKN2A/B. While homozygous CDKN2A/B loss has been directly associated with Richter transformation, we did not find this association for heterozygous loss of CDKN2A/B. Gains in 8q24.21 were either focal gains in a MYC enhancer region or large gains affecting the MYC locus, but only the latter type was highly enriched in relapsed/refractory CLL (17%). In addition to a high frequency of NOTCH1 mutations (23%), we found recurrent genetic alterations in SPEN (4% mutated), RBPJ (8% deleted) and SNW1 (8% deleted), all affecting a protein complex that represses transcription of NOTCH1 target genes. We investigated the functional impact of these alterations on HES1, DTX1 and MYC gene transcription and found derepression of these NOTCH1 target genes particularly with SPEN mutations. In summary, we provide new insights into the genomic architecture of high-risk CLL, define novel recurrent DNA copy number alterations and refine knowledge on del(9p), gain(8q) and alterations affecting NOTCH1 signaling. This study was registered at ClinicalTrials.gov with number NCT01392079.

Complex karyotype as a predictor of high-risk chronic lymphocytic leukemia: A single center experience over 12 years

OBJECTIVES

A complex karyotype (CK) is considered a poor prognostic marker in chronic lymphocytic leukemia (CLL).

METHODS

The study analyzed 644 untreated CLL patients (pts) using conventional/molecular cytogenetics to reveal the presence of a CK and its composition and to assess its predictive value. The mutational status ofTP53 was detected by next generation sequencing.

RESULTS

A CK was detected in 79 pts (12.3%). Patients with a CK showed shorter overall survival (OS) compared to those without a CK (77 months vs. 115 months, p < 0.0001). Chromosomes most frequently included in a CK were 13, 11, 17, 8, 2, and 6. The most common aberrations in a CK were translocations, numerical changes and dicentric chromosomes (with no effect on OS). Patients with aberrations ofTP53 and ATM were shown to have adverse prognosis comparable to patients with a CK without these abnormalities. A stronger impact of a CK on OS of female and older CLL patients was observed.

CONCLUSIONS

The determining of the presence of a CK is essential in modern clinical CLL practice. According to recent studies, the presence of a CK affects clinical and treatment decision-making.

Predicting the outcome of patients with chronic lymphocytic leukemia: Progress and uncertainty

Because chronic lymphocytic leukemia is a heterogeneous disease, there are considerable efforts underway to develop increasingly accurate and precise analytics with which to estimate the probability of future events such as the need for and probability of response to therapy, progression-free survival, and survival. These analytics typically are constructed from clinical and laboratory variables. These variables often are combined into scores or staging systems, some of which are prognostic (therapy-independent), whereas others are predictive (therapy-dependent). Predictive variables differ with different therapies. Because response to therapy is a necessary condition for the improvement of survival, predictive biomarkers are extremely important. However, despite some progress to identify new predictive biomarkers, del(17p)/TP53 mutation remains the only widely accepted variable used to guide therapy. New laboratory techniques and analytical tools may contribute to improvements in the precision and accuracy of outcome indicators. However, there are inherent limitations when applying cohort-based estimates to individuals within the cohort. The accuracy and precision of prediction also are limited by measurement error and chance. Ultimately, estimating outcomes requires a careful balance between clinical experience, imperfect prediction, and uncertainty.

Examination of clonal evolution in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is one of the most frequent lymphoproliferative diseases. CLL is characterized by unusual heterogeneity, which probably reflects its biological and genetic lack of homogeneity. Clonal chromosome aberrations belong to the most important prognostic and predictive factors in CLL. This research was aimed at observing clonal evolution in CLL at the chromosomal level, and assessing its clinical significance in relation to selected prognostic factors. The study involved 72 untreated patients with CLL. The preliminary investigations using cytogenetic banding analysis (CBA) and FISH were performed at the time of diagnosis, and again after about 24 months to observe clonal changes (clonal evolution). In addition, other parameters were evaluated, i.e., the expression of ZAP-70 kinase, CD38 antigen, and the mutation statuses of IGVH and NOTCH1 genes. Classic prognostic factors, i.e., categorized ZAP70 and CD38 expressions as well as mutations in IGVH and NOTCH1 genes did not influence the course of clonal evolution in the examined group of patients. Clonal evolution was detected in 45.8% of patients by means of CBA, and in 19.4% patients with FISH. Analysis of chromosomal aberrations in the examined group of patients showed that the incidence of 17p deletions and translocations in karyotypes has a negative impact on overall survival. CE was found to be a risk factor for the occurrence of disease progression (OR = 2.22). Our observations indicate that combined CBA and FISH are the most optimal techniques for monitoring clonal evolution in the course of CLL.

The combination of complex karyotype subtypes and IGHV mutational status identifies new prognostic and predictive groups in chronic lymphocytic leukaemia

BACKGROUND

Complex karyotype (CK) is a heterogeneous category with a negative impact in chronic lymphocytic leukaemia (CLL). Our group has recently reported that CK patients with major structural abnormalities (i.e. CK2) are characterised by a worse prognosis, as compared to other lesions within CK(CK1).

METHODS

We performed a multicentre retrospective study to test whether the combination of CK subtypes with IGHV status could be a relevant prognostic and predictive tool.

RESULTS

Among 522 patients 13% harboured CK2, 41% CK1 and/or U-IGHV (U-CK1) and 46% M-IGHV without any CK subtypes (M-noCK). After a median follow-up of 5.8 years, CK2 patients had the shortest TTFT (5-year TTFT 31%, 39 and 81%, p < 0.0001) and OS (5-year OS 67%, 85 and 93%, p < 0.0001) as compared to U-CK1 or M-noCK cases, regardless of TP53 abnormalities. CK2 patients also had the worst outcome after chemoimmunotherapy. In fact, the median TTNT after FCR or BR was 1.86 and 4.79 years for CK2 and U-CK1, but not reached for M-noCK patients (p < 0.0005).

CONCLUSIONS

We herein suggest that the combined assessment of the IGHV mutational status and CK subtypes refines the prognostication of CLL, allowing to identify M-IGHV patients without any CK subtypes who are characterised by an indolent disease and excellent outcome after chemoimmunotherapy.

Gain of the short arm of chromosome 2 (2p gain) has a significant role in drug-resistant chronic lymphocytic leukemia

The different types of drug resistance encountered in chronic lymphocytic leukemia (CLL) cannot be fully accounted for by the 17p deletion (and/or TP53 mutation), a complex karyotype (CK), immunoglobulin heavy‐chain variable region genes (IGHV) status and gene mutations. Hence, we sought to assess the associations between recurrent genomic abnormalities in CLL and the disease's development and outcome. To this end, we analyzed 64 samples from patients with CLL and gain of the short arm of chromosome 2 (2p+), which is frequent in late‐stage and relapsed/refractory CLL. We found that fludarabine/cyclophosphamide/rituximab (a common first‐line treatment in CLL) is not effective in removing the 2p+ clone ‐ even in samples lacking a CK, the 17p deletion or unmutated IGHV. Our results suggest strongly that patients with CLL should be screened for 2p+ (using karyotyping and fluorescence in situ hybridization) before a treatment option is chosen. Longer follow‐up is now required to evaluate bendamustine‐rituximab, ibrutinib, and idelalisib‐rituximab treatments.

The importance of complex karyotype in prognostication and treatment of chronic lymphocytic leukemia (CLL): a comprehensive review of the literature

Cytogenetic examination and the detection of chromosomal aberrations in chronic lymphocytic leukemia (CLL) is an integral part of prognostic stratification and treatment decisions. Improvements in cytogenetic methods, notably the introduction of the cell stimulation method, have led to the detection of chromosomal aberrations in 80% of CLL cases. A comprehensive analysis of cytogenetic aberrations recently showed that complex karyotypes (CKs) defined as the detection of either three or more or five or more chromosomal changes in a karyotype have a poor prognostic impact. The current efforts at the international level are focused on the goal of including CK assessment among prognostic markers for CLL patients at diagnosis as well as after treatment. This review of the literature documents the clinical importance of CK findings in CLL and the necessity of including this factor in other poor prognostic indicators.