Defining the prognosis of early stage chronic lymphocytic leukaemia patients

Impact of Minimal Residual Disease on Progression-Free Survival Outcomes After Fixed-Duration Ibrutinib-Venetoclax Versus Chlorambucil-Obinutuzumab in the GLOW Study

PURPOSE

In GLOW, fixed-duration ibrutinib + venetoclax showed superior progression-free survival (PFS) versus chlorambucil + obinutuzumab in older/comorbid patients with previously untreated chronic lymphocytic leukemia (CLL). The current analysis describes minimal residual disease (MRD) kinetics and any potential predictive value for PFS, as it has not yet been evaluated for ibrutinib + venetoclax treatment.

METHODS

Undetectable MRD (uMRD) was assessed by next-generation sequencing at <1 CLL cell per 10,000 (<10^-4) and <1 CLL cell per 100,000 (<10^-5) leukocytes. PFS was analyzed by MRD status at 3 months after treatment (EOT+3).

RESULTS

Ibrutinib + venetoclax achieved deeper uMRD (<10^-5) rates in bone marrow (BM) and peripheral blood (PB), respectively, in 40.6% and 43.4% of patients at EOT+3 versus 7.6% and 18.1% of patients receiving chlorambucil + obinutuzumab. Of these patients, uMRD (<10^-5) in PB was sustained during the first year post-treatment (EOT+12) in 80.4% of patients receiving ibrutinib + venetoclax and 26.3% receiving chlorambucil + obinutuzumab. Patients with detectable MRD (dMRD; ≥10^-4) in PB at EOT+3 were more likely to sustain MRD levels through EOT+12 with ibrutinib + venetoclax versus chlorambucil + obinutuzumab. PFS rates at EOT+12 were high among patients treated with ibrutinib + venetoclax regardless of MRD status at EOT+3: 96.3% and 93.3% in patients with uMRD (<10^-4) and dMRD (≥10^-4) in BM, respectively, versus 83.3% and 58.7% for patients receiving chlorambucil + obinutuzumab. PFS rates at EOT+12 also remained high in patients with unmutated immunoglobulin heavy-chain variable region (IGHV) receiving ibrutinib + venetoclax, independent of MRD status in BM.

CONCLUSION

Molecular and clinical relapses were less frequent during the first year post-treatment with ibrutinib + venetoclax versus chlorambucil + obinutuzumab regardless of MRD status at EOT+3 and IGHV status. Even for patients not achieving uMRD (<10^-4), PFS rates remained high with ibrutinib + venetoclax; this is a novel finding and requires additional follow-up to confirm its persistence over time.

Proteomics-Based Regression Model for Assessing the Development of Chronic Lymphocytic Leukemia

The clinical course of chronic lymphocytic leukemia (CLL) is very ambiguous, showing either an indolent nature of the disease or having latent dangerous progression, which, if diagnosed, will require an urgent therapy. The prognosis of the course of the disease and the estimation of the time of therapy initiation are crucial for the selection of a successful treatment strategy. A reliable estimating index is needed to assign newly diagnosed CLL patients to the prognostic groups. In this work, we evaluated the comparative expressions of proteins in CLL blood cells using a label-free quantification by mass spectrometry and calculated the integrated proteomic indexes for a group of patients who received therapy after the blood sampling over different periods of time. Using a two-factor linear regression analysis based on these data, we propose a new pipeline for evaluating model development for estimation of the moment of therapy initiation for newly diagnosed CLL patients.

Prognostic models for newly-diagnosed chronic lymphocytic leukaemia in adults: a systematic review and meta-analysis

BACKGROUND

Chronic lymphocytic leukaemia (CLL) is the most common cancer of the lymphatic system in Western countries. Several clinical and biological factors for CLL have been identified. However, it remains unclear which of the available prognostic models combining those factors can be used in clinical practice to predict long-term outcome in people newly-diagnosed with CLL.

OBJECTIVES

To identify, describe and appraise all prognostic models developed to predict overall survival (OS), progression-free survival (PFS) or treatment-free survival (TFS) in newly-diagnosed (previously untreated) adults with CLL, and meta-analyse their predictive performances.

SEARCH METHODS

We searched MEDLINE (from January 1950 to June 2019 via Ovid), Embase (from 1974 to June 2019) and registries of ongoing trials (to 5 March 2020) for development and validation studies of prognostic models for untreated adults with CLL. In addition, we screened the reference lists and citation indices of included studies.

SELECTION CRITERIA

We included all prognostic models developed for CLL which predict OS, PFS, or TFS, provided they combined prognostic factors known before treatment initiation, and any studies that tested the performance of these models in individuals other than the ones included in model development (i.e. 'external model validation studies'). We included studies of adults with confirmed B-cell CLL who had not received treatment prior to the start of the study. We did not restrict the search based on study design.

DATA COLLECTION AND ANALYSIS

We developed a data extraction form to collect information based on the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies (CHARMS). Independent pairs of review authors screened references, extracted data and assessed risk of bias according to the Prediction model Risk Of Bias ASsessment Tool (PROBAST). For models that were externally validated at least three times, we aimed to perform a quantitative meta-analysis of their predictive performance, notably their calibration (proportion of people predicted to experience the outcome who do so) and discrimination (ability to differentiate between people with and without the event) using a random-effects model. When a model categorised individuals into risk categories, we pooled outcome frequencies per risk group (low, intermediate, high and very high). We did not apply GRADE as guidance is not yet available for reviews of prognostic models.

MAIN RESULTS

From 52 eligible studies, we identified 12 externally validated models: six were developed for OS, one for PFS and five for TFS. In general, reporting of the studies was poor, especially predictive performance measures for calibration and discrimination; but also basic information, such as eligibility criteria and the recruitment period of participants was often missing. We rated almost all studies at high or unclear risk of bias according to PROBAST. Overall, the applicability of the models and their validation studies was low or unclear; the most common reasons were inappropriate handling of missing data and serious reporting deficiencies concerning eligibility criteria, recruitment period, observation time and prediction performance measures. We report the results for three models predicting OS, which had available data from more than three external validation studies: CLL International Prognostic Index (CLL-IPI) This score includes five prognostic factors: age, clinical stage, IgHV mutational status, B2-microglobulin and TP53 status. Calibration: for the low-, intermediate- and high-risk groups, the pooled five-year survival per risk group from validation studies corresponded to the frequencies observed in the model development study. In the very high-risk group, predicted survival from CLL-IPI was lower than observed from external validation studies. Discrimination: the pooled c-statistic of seven external validation studies (3307 participants, 917 events) was 0.72 (95% confidence interval (CI) 0.67 to 0.77). The 95% prediction interval (PI) of this model for the c-statistic, which describes the expected interval for the model's discriminative ability in a new external validation study, ranged from 0.59 to 0.83. Barcelona-Brno score Aimed at simplifying the CLL-IPI, this score includes three prognostic factors: IgHV mutational status, del(17p) and del(11q). Calibration: for the low- and intermediate-risk group, the pooled survival per risk group corresponded to the frequencies observed in the model development study, although the score seems to overestimate survival for the high-risk group. Discrimination: the pooled c-statistic of four external validation studies (1755 participants, 416 events) was 0.64 (95% CI 0.60 to 0.67); 95% PI 0.59 to 0.68. MDACC 2007 index score The authors presented two versions of this model including six prognostic factors to predict OS: age, B2-microglobulin, absolute lymphocyte count, gender, clinical stage and number of nodal groups. Only one validation study was available for the more comprehensive version of the model, a formula with a nomogram, while seven studies (5127 participants, 994 events) validated the simplified version of the model, the index score. Calibration: for the low- and intermediate-risk groups, the pooled survival per risk group corresponded to the frequencies observed in the model development study, although the score seems to overestimate survival for the high-risk group. Discrimination: the pooled c-statistic of the seven external validation studies for the index score was 0.65 (95% CI 0.60 to 0.70); 95% PI 0.51 to 0.77.

AUTHORS' CONCLUSIONS

Despite the large number of published studies of prognostic models for OS, PFS or TFS for newly-diagnosed, untreated adults with CLL, only a minority of these (N = 12) have been externally validated for their respective primary outcome. Three models have undergone sufficient external validation to enable meta-analysis of the model's ability to predict survival outcomes. Lack of reporting prevented us from summarising calibration as recommended. Of the three models, the CLL-IPI shows the best discrimination, despite overestimation. However, performance of the models may change for individuals with CLL who receive improved treatment options, as the models included in this review were tested mostly on retrospective cohorts receiving a traditional treatment regimen. In conclusion, this review shows a clear need to improve the conducting and reporting of both prognostic model development and external validation studies. For prognostic models to be used as tools in clinical practice, the development of the models (and their subsequent validation studies) should adapt to include the latest therapy options to accurately predict performance. Adaptations should be timely.

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.

Machine learning can identify newly diagnosed patients with CLL at high risk of infection

Infections have become the major cause of morbidity and mortality among patients with chronic lymphocytic leukemia (CLL) due to immune dysfunction and cytotoxic CLL treatment. Yet, predictive models for infection are missing. In this work, we develop the CLL Treatment-Infection Model (CLL-TIM) that identifies patients at risk of infection or CLL treatment within 2 years of diagnosis as validated on both internal and external cohorts. CLL-TIM is an ensemble algorithm composed of 28 machine learning algorithms based on data from 4,149 patients with CLL. The model is capable of dealing with heterogeneous data, including the high rates of missing data to be expected in the real-world setting, with a precision of 72% and a recall of 75%. To address concerns regarding the use of complex machine learning algorithms in the clinic, for each patient with CLL, CLL-TIM provides explainable predictions through uncertainty estimates and personalized risk factors.

Chronic lymphocytic leukemia is an indolent disease, and many patients succumb to infection rather than the direct effects of the disease. Here, the authors use medical records and machine learning to predict the patients that may be at risk of infection, which may enable a change in the course of their treatment.

Telomere length predicts for outcome to FCR chemotherapy in CLL

We have previously shown that dividing patients with CLL into those with telomeres inside the fusogenic range (TL-IFR) and outside the fusogenic range (TL-OFR) is powerful prognostic tool. Here, we used a high-throughput version of the assay (HT-STELA) to establish whether telomere length could predict for outcome to fludarabine, cyclophosphamide, rituximab (FCR)-based treatment using samples collected from two concurrent phase II studies, ARCTIC and ADMIRE (n = 260). In univariate analysis, patients with TL-IFR had reduced progression-free survival (PFS) (P < 0.0001; HR = 2.17) and shorter overall survival (OS) (P = 0.0002; HR = 2.44). Bifurcation of the IGHV-mutated and unmutated subsets according to telomere length revealed that patients with TL-IFR in each subset had shorter PFS (HR = 4.35 and HR = 1.48, respectively) and shorter OS (HR = 3.81 and HR = 2.18, respectively). In addition, the OS of the TL-OFR and TL-IFR subsets were not significantly altered by IGHV mutation status (P = 0.61; HR = 1.24 and P = 0.41; HR = 1.47, respectively). In multivariate modeling, telomere length was the dominant co-variable for PFS (P = 0.0002; HR = 1.85) and OS (P = 0.05; HR = 1.61). Taken together, our data suggest that HT-STELA is a powerful predictor of outcome to FCR-based treatment and could be used to inform the design of future risk-adapted clinical trials.

Limited value of routine follow-up visits in chronic lymphocytic leukemia managed initially by watch and wait: A North Denmark population-based study

INTRODUCTION

The majority of newly diagnosed chronic lymphocytic leukemia (CLL) patients are followed initially by watch and wait (WAW). Clinical practice varies and the value of frequent follow-up visits remains unclear. Thus, in this study we investigated the clinical value of follow-up visits for patients with CLL.

METHODS

We collected data from diagnosis and follow-up visits for patients diagnosed with CLL and managed by WAW in the North Denmark Region between 2007-2014. High- and low-risk group patients were determined by Binet stage, IgVH status, and cytogenetics at diagnosis. The effect of risk group allocation on the probability of receiving CLL-directed treatment within two years was included in a multivariable logistic regression model adjusted for age and blood test results.

RESULTS

273 patients were included in the study with a median follow-up of 3 years (IQR: 1.6-5.4). Overall, the median interval between follow-up visits was 98 days (95% CI: 96-100) (high-risk patients: 91 days [95% CI: 86-95] vs. low-risk patients: 105 days [95% CI: 100-110]). Among 2,312 follow-up visits, only 387 (17%) were associated with interventions. At the following time points: 6 months, 1 year, and 1.5 years, patients with low-risk CLL had significantly lower odds of initiating treatment compared to patients with high-risk CLL.

CONCLUSION

WAW plays an important role in managing CLL. Interventions at follow-up visits were infrequent and low-risk patients had significantly lower risk of treatment initiation. We question the value of routine follow-up in CLL in the absence of changes in symptoms and/or blood test results.

Reproducible diagnosis of chronic lymphocytic leukemia by flow cytometry: An European Research Initiative on CLL (ERIC) & European Society for Clinical Cell Analysis (ESCCA) Harmonisation project

The diagnostic criteria for CLL rely on morphology and immunophenotype. Current approaches have limitations affecting reproducibility and there is no consensus on the role of new markers. The aim of this project was to identify reproducible criteria and consensus on markers recommended for the diagnosis of CLL. ERIC/ESCCA members classified 14 of 35 potential markers as “required” or “recommended” for CLL diagnosis, consensus being defined as >75% and >50% agreement, respectively. An approach to validate “required” markers using normal peripheral blood was developed. Responses were received from 150 participants with a diagnostic workload >20 CLL cases per week in 23/150 (15%), 5–20 in 82/150 (55%), and <5 cases per week in 45/150 (30%). The consensus for “required” diagnostic markers included: CD19, CD5, CD20, CD23, Kappa, and Lambda. “Recommended” markers potentially useful for differential diagnosis were: CD43, CD79b, CD81, CD200, CD10, and ROR1. Reproducible criteria for component reagents were assessed retrospectively in 14,643 cases from 13 different centers and showed >97% concordance with current approaches. A pilot study to validate staining quality was completed in 11 centers. Markers considered as “required” for the diagnosis of CLL by the participants in this study (CD19, CD5, CD20, CD23, Kappa, and Lambda) are consistent with current diagnostic criteria and practice. Importantly, a reproducible approach to validate and apply these markers in individual laboratories has been identified. Finally, a consensus “recommended” panel of markers to refine diagnosis in borderline cases (CD43, CD79b, CD81, CD200, CD10, and ROR1) has been defined and will be prospectively evaluated. © 2017 International Clinical Cytometry Society

The mutational landscape of chronic lymphocytic leukemia and its impact on prognosis and treatment

The typical genome of chronic lymphocytic leukemia (CLL) carries ∼2000 molecular lesions. Few mutations recur across patients at a frequency >5%, whereas a large number of biologically and clinically uncharacterized genes are mutated at lower frequency. Approximately 80% of CLL patients carry at least 1 of 4 common chromosomal alterations, namely deletion 13q14, deletion 11q22-23, deletion 17p12, and trisomy 12. Knowledge of the CLL genome has translated into the availability of molecular biomarkers for prognosis and treatment prediction. Prognostic biomarkers do not affect treatment choice, and can be integrated into prognostic scores that are based on both clinical and biological variables. Molecular predictive biomarkers affect treatment choice, and currently include TP53 disruption by mutation and/or deletion and IGHV mutation status. TP53 disruption by gene mutation and/or deletion associates with chemoimmunotherapy failure and mandates treatment with innovative drugs, including ibrutinib, idelalisib, or venetoclax. The mutation status of IGHV genes represents a predictive biomarker for identifying patients that may benefit the most from chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab. Assessment of these biomarkers at the time of treatment requirement is recommended by most current guidelines for CLL management. Other molecular predictors are under investigation, but their application in clinical practice is premature.

Chronic lymphocytic leukemia: A prognostic model comprising only two biomarkers (IGHV mutational status and FISH cytogenetics) separates patients with different outcome and simplifies the CLL-IPI

Rai and Binet staging systems are important to predict the outcome of patients with chronic lymphocytic leukemia (CLL) but do not reflect the biologic diversity of the disease nor predict response to therapy, which ultimately shape patients' outcome. We devised a biomarkers-only CLL prognostic system based on the two most important prognostic parameters in CLL (i.e., IGHV mutational status and fluorescence in situ hybridization [FISH] cytogenetics), separating three different risk groups: (1) low-risk (mutated IGHV + no adverse FISH cytogenetics [del(17p), del(11q)]); (2) intermediate-risk (either unmutated IGHV or adverse FISH cytogenetics) and (3) high-risk (unmutated IGHV + adverse FISH cytogenetics). In 524 unselected subjects with CLL, the 10-year overall survival was 82% (95% CI 76%-88%), 52% (45%-62%), and 27% (17%-42%) for the low-, intermediate-, and high-risk groups, respectively. Patients with low-risk comprised around 50% of the series and had a life expectancy comparable to the general population. The prognostic model was fully validated in two independent cohorts, including 417 patients representative of general CLL population and 337 patients with Binet stage A CLL. The model had a similar discriminatory value as the CLL-IPI. Moreover, it applied to all patients with CLL independently of age, and separated patients with different risk within Rai or Binet clinical stages. The biomarkers-only CLL prognostic system presented here simplifies the CLL-IPI and could be useful in daily practice and to stratify patients in clinical trials.

Identifying High-Risk Chronic Lymphocytic Leukemia: A Pathogenesis-Oriented Appraisal of Prognostic and Predictive Factors in Patients Treated with Chemotherapy with or without Immunotherapy

Chronic lymphocytic leukemia (CLL) displays an extremely variable clinical behaviour. Accurate prognostication and prediction of response to treatment are important in an era of effective first-line regimens and novel molecules for high risk patients. Because a plethora of prognostic biomarkers were identified, but few of them were validated by multivariable analysis in comprehensive prospective studies, we applied in this survey stringent criteria to select papers from the literature in order to identify the most reproducible prognostic/predictive markers. Each biomarker was analysed in terms of reproducibility across the different studies with respect to its impact on time to first treatment (TTFT), progression free survival (PFS), overall survival (OS) and response to treatment. We were able to identify the following biomarkers as the most reliable in guiding risk stratification in the daily clinical practice: 17p-/TP53 mutations, IGHV unmutated configuration, short telomeres and 11q-. However, the method for measuring telomere length was not validated yet and 11q- was predictive of inferior OS only in those patients who did not receive FCR-like combinations. Stage and lymphocytosis were predictive of shorter TTFT and age, high serum thymidine kinase levels and poor performance status were predictive of shorter OS. Using our criteria no parameter was found to independently predict for inferior response to treatment.

Heightened BTK-dependent cell proliferation in unmutated chronic lymphocytic leukemia confers increased sensitivity to ibrutinib

In chronic lymphocytic leukemia (CLL), patients with unmutated immunoglobulin heavy chain variable region gene (UM-CLL) have worse outcomes than mutated CLL (M-CLL) following chemotherapy or chemoimmunotherapy. However, in the era of BCR-targeted therapies, the adverse prognostic impact of unmutated IGHV seems to be diminishing, and there are clinical datasets showing unexpected improved responses in UM-CLL. We investigated the biological differences of BTK activity between these subgroups and further compared the impact of ibrutinib on molecular and cellular behaviors. Immunoblotting analysis revealed that phosphorylated active BTK is significantly higher in UM-CLL. Moreover, UM-CLL, compared to M-CLL, displayed a much higher proliferative capacity that was correlated with higher phospho-BTK and greater sensitivity to ibrutinib. In addition, BTK depletion with siRNA led to a more prominent reduction in the proliferation of UM-CLL, suggesting that elevated BTK activity is responsible for increased cell proliferation. Further, cell signaling activity by multiple measurements was consistently higher in UM-CLL accompanied by a higher sensitivity to ibrutinib. These studies link UM-CLL to elevated BCR signaling, heightened BTK-dependent cell proliferation and increased sensitivity to ibrutinib. The prognostic significance of IGHV mutation should be reevaluated in the era of new therapies targeting BCR signaling.

Key Molecular Drivers of Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is an adult neoplastic disease of B cells characterized by variable clinical outcomes. Although some patients have an aggressive form of the disease and often encounter treatment failure and short survival, others have more stable disease with long-term survival and little or no need for theraphy. In the past decade, significant advances have been made in our understanding of the molecular drivers that affect the natural pathology of CLL. The present review describes what is known about these key molecules in the context of their role in tumor pathogenicity, prognosis, and therapy.

Should IGHV status and FISH testing be performed in all CLL patients at diagnosis? A systematic review and meta-analysis

Since the first description of the natural history of chronic lymphocytic leukemia (CLL) by David Galton in 1966, the considerable heterogeneity in the disease course has been well recognized. The Rai and Binet staging systems described ∼40 years ago have proven to be robust prognostic tools. Over the past 2 decades, several novel biological, genetic, and molecular markers have been shown to be useful adjuncts to the Rai and Binet staging systems. In this systematic review, we examined the role of immunoglobulin heavy-chain variable region gene (IGHV) mutation status and genetic abnormalities determined by interphase fluorescence in situ hybridization (FISH) in patients with newly diagnosed CLL. The cumulative evidence presented in this systematic review is sufficient to recommend that FISH and IGHV be performed as standard clinical tests for all patients with newly diagnosed CLL in those countries with the resources to do so. In addition to clinical stage, these parameters could represent the minimal standard initial prognostic evaluation for patients with CLL. This approach will allow the application of powerful, recently developed prognostic indices (all of which are dependent on IGHV and FISH results) to all patients with newly diagnosed CLL.

Prognostic indices in chronic lymphocytic leukaemia: where do we stand how do we proceed?

The remarkable clinical heterogeneity in chronic lymphocytic leukaemia (CLL) has highlighted the need for prognostic and predictive algorithms that can be employed in clinical practice to assist patient management and therapy decisions. Over the last 20 years, this research field has been rewarding and many novel prognostic factors have been identified, especially at the molecular genetic level. Whilst detection of recurrent cytogenetic aberrations and determination of the immunoglobulin heavy variable gene somatic hypermutation status have an established role in outcome prediction, next-generation sequencing has recently revealed novel mutated genes with clinical relevance (e.g. NOTCH1, SF3B1 and BIRC3). Efforts have been made to combine variables into prognostic indices; however, none has been universally adopted. Although a unifying model for all groups of patients and in all situations is appealing, this may prove difficult to attain. Alternatively, focused efforts on patient subgroups in the same clinical context and at certain clinically relevant 'decision points', that is at diagnosis and at initiation of first-line or subsequent treatments, may provide a more accurate approach. In this review, we discuss the advantages and disadvantages as well as the clinical applicability of three recently proposed prognostic models, the MD Anderson nomogram, the integrated cytogenetic and mutational model and the CLL-international prognostic index. We also consider future directions taking into account novel aspects of the disease, such as the tumour microenvironment and the dynamics of (sub)clonal evolution. These aspects are particularly relevant in view of the increasing number of new targeted therapies that have recently emerged.

Management of chronic lymphocytic leukemia

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) is usually diagnosed in asymptomatic patients with early-stage disease. The standard management approach is careful observation, irrespective of risk factors unless patients meet the International Workshop on CLL (IWCLL) criteria for "active disease," which requires treatment. The initial standard therapy for most patients combines an anti-CD20 antibody (such as rituximab, ofatumumab, or obinutuzumab) with chemotherapy (fludarabine/cyclophosphamide [FC], bendamustine, or chlorambucil) depending on multiple factors including the physical fitness of the patient. However, patients with very high-risk CLL because of a 17p13 deletion (17p-) with or without mutation of TP53 (17p-/TP53mut) have poor responses to chemoimmunotherapy and require alternative treatment regimens containing B-cell receptor (BCR) signaling pathway inhibitors. The BCR signaling pathway inhibitors (ibrutinib targeting Bruton's tyrosine kinase [BTK] and idelalisib targeting phosphatidyl-inositol 3-kinase delta [PI3K-delta], respectively) are currently approved for the treatment of relapsed/refractory CLL and all patients with 17p- (ibrutinib), and in combination with rituximab for relapsed/refractory patients (idelalisib). These agents offer great efficacy, even in chemotherapy refractory CLL, with increased tolerability, safety, and survival. Ongoing studies aim to determine the best therapy combinations with the goal of achieving long-term disease control and the possibility of developing a curative regimen for some patients. CLL is associated with a wide range of infectious, autoimmune, and malignant complications. These complications result in considerable morbidity and mortality that can be minimized by early detection and aggressive management. This active monitoring requires ongoing patient education, provider vigilance, and a team approach to patient care.

Evaluation of serum markers in the LRF CLL4 trial: β2-microglobulin but not serum free light chains, is an independent marker of overall survival

Chronic lymphocytic leukemia (CLL) is characterized by heterogeneous clinical behavior and there is a need for improved biomarkers. The current study evaluated the prognostic significance of serum free light chains (sFLC, kappa, and lambda) and other serum markers (bar, serum thymidine kinase (sTK), soluble CD23, and LDH) together with established biomarkers in 289 patients enrolled into the LRF CLL4 trial. In a multivariable analysis of serum markers alone, higher big and kappa light chains were statistically significant in predicting disease progression and higher blg, and sTK in predicting mortality. In multivariable analysis for overall survival the following were independently significant: β2M levels, immunoglobulin gene (IGHV) mutational status (>98% homology), age, 17p13 deletions (>10%), and CD38 expression. β2M is the only serum marker that retained clear independent value as a biomarker in the LRF CLL4 trial and remains powerfully prognostic requiring evaluation in any future method of risk stratifying patients.

Genomic Features: Impact on Pathogenesis and Treatment of Chronic Lymphocytic Leukemia

Genomic markers are among the strongest prognostic factors in chronic lymphocytic leukemia (CLL). Chromosomal aberrations, IGHV and TP53 mutation status are well-established and essential to discriminate between a more indolent course of disease and a high-risk CLL, which requires an alternative treatment regimen. In addition, a variety of gene mutations with unclear prognostic value have been identified: SF3B1, ATM, and BIRC3 may describe CLL with adverse outcome, whereas NOTCH1 is predictive for resistance against CD20 antibodies. Integration of novel drivers into a small set of key pathways forms the basis for future pathogenetic and therapeutic implications.

Prognostic markers and standard management of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is usually diagnosed in early stage, asymptomatic patients, and, although a wealth of prognostic parameters have been identified, the standard approach is a “watch and wait” strategy irrespective of risk factors. Therapy is only indicated if “active disease” criteria (International Workshop on Chronic Lymphocytic Leukemia guidelines) are met, and the routine upfront treatment is a combination of CD20 antibody (rituximab, ofatumumab or obinutuzumab) and chemotherapy (fludarabine /cyclophosphamide, bendamustine, chlorambucil), with the choice mainly determined by physical fitness of the patient. The major subgroup in which this approach does not result into satisfactory efficacy is in CLL with 17p deletion (17p−) or TP53 mutation (TP53mut). Likewise, patients with a short initial response duration (i.e., <24-26 months) have a dismal outcome with chemoimmunotherapy salvage. Therefore, these patients have been referred to as “ultra high risk,” and, in these subgroups, novel agents such as signaling kinase inhibitors (also termed B-cell receptor signaling inhibitors; e.g., ibrutinib targeting Bruton tryosine kinase, idelalisib targeting phosphoinositide 3-kinase) and BCL2 antagonists (venetoclax, formerly ABT-199/GDC-0199) have shown dramatic efficacy. Ibrutinib and idelalisib are currently approved for the treatment of relapsed or refractory CLL or frontline treatment of 17p−/TP53mut CLL regardless of fitness. Therefore, these agents are challenging the concept of adjusting treatment to fitness and TP53 status, because they offer remarkable efficacy combined with exceptional tolerability. Nevertheless, it appears that 17p−/TP53mut retains an adverse prognostic impact, making additional improvement a primary research goal aimed at the development of the best combinations and/or sequences of these new agents, as well as prognostic and predictive markers guiding their use.

Primary care management of early stage chronic lymphocytic leukaemia is safe and effective

BACKGROUND

Chronic lymphocytic leukaemia (CLL) is the commonest leukaemia in western society. Most patients are detected incidentally at an early stage and require 'watch and wait' follow-up. In the UK, management of Stage A0 CLL varies with some centres advising regular outpatient haematology follow-up, whereas others recommend management within primary care. The safety and effectiveness of these two management options are currently unknown.

METHODS

An observational retrospective cohort study in outpatient Haematology clinics at Queen Elizabeth Hospital Birmingham (QEH) and Birmingham Heartlands Hospital (BHH) and primary care practices in West Midlands, UK. All patients diagnosed with stable stage A0 CLL since 2002 at BHH or QEH were identified. At BHH, patients were discharged to primary care follow-up, whilst QEH patients remained under haematology for follow-up. Evidence of disease progression, need for treatment and overall mortality was documented.

RESULTS

Two hundred and forty-six Stage A0 CLL patients were identified. One hundred and five (43%) patients were discharged to primary care, whilst 141 (57%) patients were followed up in haematology outpatient clinics. No difference in mortality or need for treatment was found between the two groups. Of those discharged, 93 (66%) remained in primary care.

CONCLUSION

The management of stable-stage A0 CLL within primary or secondary care leads to equivalent clinical outcomes. The prevalence of early-stage CLL is expected to increase with the ageing population and management within primary care should be considered as a potentially effective approach.

Prognostic signature and clonality pattern of recurrently mutated genes in inactive chronic lymphocytic leukemia

An increasing numbers of patients are being diagnosed with asymptomatic early-stage chronic lymphocytic leukemia (CLL), with no treatment indication at baseline. We applied a high-throughput deep-targeted analysis, especially designed for covering widely TP53 and ATM genes, in 180 patients with inactive disease at diagnosis, to test the independent prognostic value of CLL somatic recurrent mutations. We found that 40/180 patients harbored at least one acquired variant with ATM (n=17, 9.4%), NOTCH1 (n=14, 7.7%), TP53 (n=14, 7.7%) and SF3B1 (n=10, 5.5%) as most prevalent mutated genes. Harboring one ‘sub-Sanger' TP53 mutation granted an independent 3.5-fold increase of probability of needing treatment. Those patients with a double-hit ATM lesion (mutation+11q deletion) had the shorter median time to first treatment (17 months). We found that a genomic variable: TP53 mutations, most of them under the sensitivity of conventional techniques; a cell phenotypic factor: CD38-positive expression; and a classical marker as β2-microglobulin, remained as the unique independent predictors of outcome. The high-throughput determination of TP53 status, particularly in this set of patients frequently lacking high-risk chromosomal aberrations, emerges as a key step, not only for prediction modeling, but also for exploring mutation-specific therapeutic approaches and minimal residual disease monitoring.

CD49d is the strongest flow cytometry-based predictor of overall survival in chronic lymphocytic leukemia

PURPOSE

Although CD49d is an unfavorable prognostic marker in chronic lymphocytic leukemia (CLL), definitive validation evidence is lacking. A worldwide multicenter analysis was performed using published and unpublished CLL series to evaluate the impact of CD49d as an overall (OS) and treatment-free survival (TFS) predictor.

PATIENTS AND METHODS

A training/validation strategy was chosen to find the optimal CD49d cutoff. The hazard ratio (HR) for death and treatment imposed by CD49d was estimated by pooled analysis of 2,972 CLLs; Cox analysis stratified by center and stage was used to adjust for confounding variables. The importance of CD49d over other flow cytometry-based prognosticators (eg, CD38, ZAP-70) was ranked by recursive partitioning.

RESULTS

Patients with ≥ 30% of neoplastic cells expressing CD49d were considered CD49d+. Decrease in OS at 5 and 10 years among CD49d+ patients was 7% and 23% (decrease in TFS, 26% and 25%, respectively). Pooled HR of CD49d for OS was 2.5 (2.3 for TFS) in univariate analysis. This HR remained significant and of similar magnitude (HR, 2.0) in a Cox model adjusted for clinical and biologic prognosticators. Hierarchic trees including all patients or restricted to those with early-stage disease or those age ≤ 65 years always selected CD49d as the most important flow cytometry-based biomarker, with negligible additional prognostic information added by CD38 or ZAP-70. Consistently, by bivariate analysis, CD49d reliably identified patient subsets with poorer outcome independent of CD38 and ZAP-70.

CONCLUSION

In this analysis of approximately 3,000 patients, CD49d emerged as the strongest flow cytometry-based predictor of OS and TFS in CLL.

ZAP70 in B-CLL cells related to the expression in NK cells is a surrogate marker for mutational status

The strongest prognostic factor in chronic B-cell lymphocytic leukemia (CLL) is the mutational status of the immunoglobulin heavy chain variable region (IGHV) genes. Determination of this mutational status is laborious and therefore not applied in routine diagnostics. A search for "surrogate markers" has been conducted over the past few years. One of the most promising surrogate markers is ZAP70, but standardization of the measurement of ZAP70 has proven to be difficult. Conventionally, ZAP70 expression in CLL cells is related to ZAP70 expression in T cells. We propose a new method in which ZAP70 expression in NK cells is used as reference (new NK-MFI method). We have measured ZAP70 expression in samples of 45 previously untreated CLL patients. ZAP70 in CLL cells related to ZAP70 in NK cells correlated better to cytogenetic risk profile and mutational status than the conventional methods. Negativity of both ZAP70 (new NK-MFI method) and CD38 resulted in a probability of 90% for mutated IGHV genes. In conclusion, ZAP70 expression in CLL cells related to ZAP70 expression in NK cells is a better surrogate marker for mutational status than the conventional T cell related methods.

Multiple productive immunoglobulin heavy chain gene rearrangements in chronic lymphocytic leukemia are mostly derived from independent clones

In chronic lymphocytic leukemia, usually a monoclonal disease, multiple productive immunoglobulin heavy chain gene rearrangements are identified sporadically. Prognostication of such cases based on immunoglobulin heavy variable gene mutational status can be problematic, especially if the different rearrangements have discordant mutational status. To gain insight into the possible biological mechanisms underlying the origin of the multiple rearrangements, we performed a comprehensive immunogenetic and immunophenotypic characterization of 31 cases with the multiple rearrangements identified in a cohort of 1147 patients with chronic lymphocytic leukemia. For the majority of cases (25/31), we provide evidence of the co-existence of at least two B lymphocyte clones with a chronic lymphocytic leukemia phenotype. We also identified clonal drifts in serial samples, likely driven by selection forces. More specifically, higher immunoglobulin variable gene identity to germline and longer complementarity determining region 3 were preferred in persistent or newly appearing clones, a phenomenon more pronounced in patients with stereotyped B-cell receptors. Finally, we report that other factors, such as TP53 gene defects and therapy administration, influence clonal selection. Our findings are relevant to clonal evolution in the context of antigen stimulation and transition of monoclonal B-cell lymphocytosis to chronic lymphocytic leukemia.

Prognostic markers and their clinical applicability in chronic lymphocytic leukemia: where do we stand?

Chronic lymphocytic leukemia (CLL) is a clinically and biologically heterogeneous disease where the majority of patients have an indolent disease course, while others may experience a far more aggressive disease, treatment failure and poor overall survival. During the last two decades, there has been an intense search to find novel biomarkers that can predict prognosis as well as guide treatment decisions. Two of the most reliable molecular prognostic markers, both of which are offered in routine diagnostics, are the immunoglobulin heavy chain variable (IGHV) gene mutational status and fluorescence in situ hybridization (FISH) detection of prognostically relevant genomic aberrations (e.g. 11q-, 13q-, +12 and 17p-). In addition to these markers, a myriad of additional biomarkers have been postulated as potential prognosticators in CLL, on the protein (e.g. CD38, ZAP70, TCL1), the RNA (e.g. LPL, CLLU1, micro-RNAs) and the genomic (e.g. TP53, NOTCH1, SF3B1 and BIRC3 mutations) level. Efforts are now being made to test these novel markers in larger patient cohorts as well as in prospective trials, with the ultimate goal to combine the "best" markers in a "CLL prognostic index" applicable for the individual patient. Although it is clear that these studies have significantly improved our knowledge regarding both prognostication and the biology of the disease, there is still an immediate need for recognizing biomarkers that can predict therapy response, and efforts should now focus on addressing this pertinent issue. In the present article, we review the extensive literature in the field of prognostic markers in CLL, focus on the most clinically relevant markers and discuss future directions regarding biomarkers in CLL.

The utility of two prognostic models for predicting time to first treatment in early chronic lymphocytic leukemia patients: results of a comparative analysis

The use of both traditional and novel prognostic parameters combined in a statistical model for predicting patient clinical outcome has been recently proposed by both MD Anderson Cancer Center (MDACC) and German chronic lymphocytic leukemia (CLL) group. Using time to first treatment (TTFT) as end-point, we performed a comparative external validation of MDACC score versus a modified version of German score, which excluded thymidine kinase measurement, in a prospective, multicenter, community-based cohort consisting of 328 patients who had asymptomatic, early stage CLL. With both models a significant correlation between higher score and shorter TTFT could be found. As a matter of fact, patients with total point score ≥25 according to MDACC model (HR, 3.27; 95% CI, 2.07-5.18; P<0.0001) or ≥2 according to modified German model (HR, 2.02; 95% CI, 1.29-3.16; P=0.002) were more likely to receive therapy. Both models provided similar results in terms of sensitivity (MDACC score, 61.5%; modified German score, 57.7%; P=0.79), whereas specificity was significantly higher for MDACC score (72.1% versus 63%; P=0.02). The prognostic utility of either MDACC or modified German score was assessed by time-dependent Receiver Operating Characteristic (ROC) analysis. Results of this comparative analysis showed that after the 2nd year area under curve (AUC) for TTFT was higher than 0.60 for both models and kept unmodified this trend over the time. Results of this study suggest that in CLL both MDACC and modified German score group should be considered the benchmarking of comparison for any novel prognostic proposal having as endpoint TTFT in CLL and including both traditional and newer prognostic parameters.

External validation on a prospective basis of a nomogram for predicting the time to first treatment in patients with chronic lymphocytic leukemia

BACKGROUND

A nomogram that incorporates traditional and newer prognostic factors to identify patients with chronic lymphocytic leukemia (CLL) who are at high risk of receiving therapy was developed by investigators at The University of Texas M. D. Anderson Cancer Center (MDACC). Because the model required validation before its extensive use could be recommended, the authors sought to externally validate the nomogram in an independent, community-based cohort of patients with CLL.

METHODS

In total, 328 previously untreated patients with newly diagnosed, asymptomatic, Binet stage A CLL from different primary hematology centers who were registered on a prospective basis during 2006 to 2010 on an observational database of the Italian Lymphoma Study Group were considered suitable for external validation of the model.

RESULTS

A total point score was calculated for each patient using a formula proposed by MDACC investigators, and the median score was 19.9 (range, 0-69.5). Furthermore, when the score was evaluated as continuous variable (ie, by measuring the risk of each point increase), the total point score was associated with the time to first treatment (hazard ratio [HR], 1.04; 95% confidence interval [CI], 1.02-1.05; P < .0001). Receiver operating characteristic analysis identified a point score of 25 (area under curve; 0.64; sensitivity, 61.5; specificity, 72.1; P < .0001) as the best threshold capable of separating patients who needed therapy from patients who did not (HR, 3.27; 95% CI, 2,07-5.18; P < .0001). The prognostic index category also remained a predictor of the time to first treatment when the analysis was limited to patients with Rai stage 0 disease (HR, 4.05; 95% CI, 2.25-7.52; P < .0001). Finally, a goodness-of-fit test demonstrated that the nomogram model had a significantly good fit at 2 years (correlation coefficient [r(2) ] = 0.966; P = .002).

CONCLUSIONS

The current results confirmed the ability of a newly developed prognostic index to predict the time to first treatment among previously untreated patients with CLL who had early disease and extended the utility of the model to those with Rai stage 0 disease. In addition, the actual and predicted time to first treatment outcomes revealed good agreement, suggesting that, externally, the results provided by the model are well calibrated. Cancer 2013. © 2012 American Cancer Society.

Pitfalls and limitations of ZAP-70 detection in chronic lymphocytic leukemia

Zeta-associated protein of 70 kDa (ZAP-70) is a tyrosine kinase that plays a role in signal transduction from the T-cell receptor. ZAP-70 is expressed in normal T-cells and NK-cells. Increased expression of ZAP-70 has been identified in chronic lymphocytic leukemia (CLL). CLL patients with increased ZAP-70 expression have significantly worse prognosis in terms of both progression-free survival and overall survival. There are several methods to quantify ZAP-70: polymerase chain reaction (PCR), immunoblotting, immunohistochemistry, and flow cytometry. Use of flow cytometry for ZAP-70 detection seems to be advantageous as this technique enables us to assess the presence of ZAP-70 separately on CLL clone, T-cells, and NK-cells. On the other hand, detection of ZAP-70 by flow cytometry is substantially influenced by many variables. The principal drawback of flow cytometry is the absence of consensus regarding selection of optimal anti-ZAP-70 antibody, fluorochrome conjugate, the most reliable staining technique, and optimal positivity threshold. This article summarizes pitfalls of flow cytometric analysis of ZAP-70 in CLL.

Addition of granulocyte macrophage colony stimulating factor does not improve response to early treatment of high-risk chronic lymphocytic leukemia with alemtuzumab and rituximab

Thirty-three previously untreated patients with high-risk chronic lymphocytic leukemia (CLL) were treated before meeting standard criteria with alemtuzumab and rituximab. Granulocyte macrophage colony stimulating factor (GM-CSF) was added to the regimen to determine whether it would improve treatment efficacy without increasing toxicity. High risk was defined as at least one of the following: 17p13-; 11q22.3-; unmutated IGHV (or use of VH3-21) together with elevated expression of ZAP-70 and/or CD38. Treatment was subcutaneous GM-CSF 250 μg Monday-Wednesday-Friday for 6 weeks from day 1, subcutaneous alemtuzumab 3 mg-10 mg-30 mg from day 3 and then 30 mg Monday-Wednesday-Friday for 4 weeks, and intravenous rituximab (375 mg/m(2)/week) for 4 weeks from day 8. Patients received standard supportive care and were monitored weekly for cytomegalovirus (CMV) reactivation. Using standard criteria, 31 (94%) patients responded to treatment, with nine (27%) complete responses (one with persistent cytopenia) and nine (27%) nodular partial responses. Median progression-free survival was 13.0 months and time to next treatment was 33.5 months. No patient died during treatment, seven (21%) had grade 3-4 toxicities attributable to treatment, and 10 (30%) had CMV viremia. Addition of GM-CSF to therapy with alemtuzumab and rituximab decreased treatment efficacy and increased the rate of CMV reactivation compared to a historical control.

Molecular testing in melanoma

Melanoma is the deadliest form of skin cancer and is increasing in incidence. Recent treatment advances have been made, but there remains a need for continued development of effective therapy options, as treatment rarely leads to cure. Many melanomas contain somatic mutations involved in tumor pathogenesis. Accurate identification of these mutations is necessary to stratify patients for the purpose of treatment and potential for clinical trials, given the absence or presence of a specific mutation. There are a number of techniques available that will identify genetic mutations and genomic aberrations present within melanoma tumor samples which are reviewed here. The type of mutation and sample number will drive selection of a given mutation detection strategy. The strengths and weaknesses, along with limitations, of the various methods will also be discussed. The discovery of somatic mutations integral in melanoma will increase our understanding of tumor pathogenesis and should facilitate identification of mutations relevant to clinical treatment decisions, advancing progress toward personalized medicine.

Predicting clinical outcome in B-chronic lymphocytic leukemia

B-Chronic lymphocytic leukemia (CLL) is a relatively common B-cell malignancy that has a very heterogeneous clinical course, despite carrying the designation of "chronic," which is a gross oversimplification. Being able to give some estimate of the rates of disease progression and overall survival (OS) at first diagnosis is, therefore, important in CLL. The ability to accurately predict response to therapy, as well as subsequent duration of response to therapy, is required given the variability of current therapies to induce and sustain treatment responses. The holy grail of prognostics would be to state with accuracy which therapy or types of therapy are best for a given patient. Although there is no complete answer to prognostic counseling, there is a continued development of markers specific to the CLL B cell and/or to its environment, as well as of testing of prognostic models. These models use both traditional and novel prognostic markers that can aid in the dissection of outcome for early-stage CLL in terms of progression risk and time to therapy. This has resulted in significant enhancement of our ability to guide and predict outcome for our patients with CLL.