Characterizing and prognosticating chronic lymphocytic leukemia in the elderly: prospective evaluation on 455 patients treated in the United States

The Five "Ws" of Frailty Assessment and Chronic Lymphocytic Leukemia: Who, What, Where, Why, and When

Chronic lymphocytic leukemia (CLL) is a disease of the elderly, but chronological age does not accurately discriminate frailty status at the inter-individual level. Frailty describes a person's overall resilience. Since CLL is a stressful situation, it is relevant to assess the patient´s degree of frailty, especially before starting antineoplastic treatment. We are in the era of targeted therapies, which have helped to control the disease more effectively and avoid the toxicity of chemo (immuno) therapy. However, these drugs are not free of side effects and other aspects arise that should not be neglected, such as interactions, previous comorbidities, or adherence to treatment, since most of these medications are taken continuously. The challenge we face is to balance the risk of toxicity and efficacy in a personalized way and without forgetting that the most frequent cause of death in CLL is related to the disease. For this purpose, comprehensive geriatric assessment (GA) provides us with the opportunity to evaluate multiple domains that may affect tolerance to treatment and that could be improved with appropriate interventions. In this review, we will analyze the state of the art of GA in CLL through the five Ws.

Mapping comorbidity in chronic lymphocytic leukemia: impact of individual comorbidities on treatment, mortality, and causes of death

Comorbid conditions are highly prevalent in chronic lymphocytic leukemia (CLL), nevertheless, detailed information on the association of specific comorbidities with CLL prognosis is missing. Using Danish, nation-wide registers, we followed consecutive patients from CLL-diagnosis in 1997-2018, until death or end of follow-up. Sub-grouping of comorbidities was defined using a modified Charlson comorbidity index. Patients were matched on sex, date of birth (±1 month), and region of residency with up to ten comparators from the general population. In total, 9170 patients with CLL were included in the study, with a median of 5.0 years of follow-up. All comorbid conditions studied were individually associated with increased mortality, and many also with increased cause-specific mortality, related or unrelated to CLL. Comorbidity correlated with increased mortality from infections and cardiovascular disease. CLL patients, particularly older, had a significant loss of lifetime compared with the general population. This study highlights a large subgroup of comorbid CLL patients with an unmet treatment-need and missing efficacy and safety data on treatment, who are under-prioritized in clinical trials. Also, studies assessing interventions that may provide better tolerability of treatment in older or comorbid patients, with cancer in general, and CLL in particular, are warranted.

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.

The Connect CLL Registry: final analysis of 1494 patients with chronic lymphocytic leukemia across 199 US sites

Optimal treatment of chronic lymphocytic leukemia (CLL) remains unclear. The Connect CLL Registry, a United States-based multicenter prospective observational cohort study, enrolled 1494 patients between 2010 and 2014 from predominantly community-based settings. Patients were grouped by line of therapy (LOT) at enrollment. With a median follow-up of 46.6 months (range, 0-63.0 months), median overall survival (OS) was not reached in LOT1, 63.0 months (95% confidence interval [CI], 46.0-63.0 months) in LOT2, and 38.0 months (95% CI, 33.0-47.0 months) in LOT≥3. Bendamustine and rituximab (BR; 33.5%); fludarabine, cyclophosphamide, and rituximab (FCR; 21.4%); and rituximab monotherapy (18.5%) were the most common regimens across LOTs. Median event-free survival (EFS) was similar in patients treated with BR (59.0 months) and FCR (55.0 months) in LOT1; median OS was not reached. In multivariable analysis, BR or FCR vs other treatments in LOT1 was associated with improved EFS (hazard ratio [HR], 0.60; P < .0001) and OS (0.67; P = .0162). Using the Kaplan-Meier product limit, ibrutinib vs other treatments improved OS in LOT2 (HR, 0.279; P = .009), LOT3 (0.441; P = .011), and LOT≥4 (0.578; P = .043). Prognostic modeling of death at 2 years postenrollment identified 3 risk groups: low (mortality rate, 6.2%), medium (14.5%), and high (27.4%). The most frequent adverse events across LOTs were pneumonia (11.6%) and febrile neutropenia (6.2%). These data suggest that advantages of LOT1 FCR over BR seen in clinical trials may not translate to community practice, whereas receiving novel LOT2 agents improved outcomes. This trial was registered at www.clinicaltrials.gov as NCT01081015.

Treatment patterns, adverse events, and economic burden in a privately insured population of patients with chronic lymphocytic leukemia in the United States

INTRODUCTION

Contemporary data describing treatment patterns, adverse events (AEs), and outcomes in patients with chronic lymphocytic leukemia (CLL) in clinical practice are lacking. We conducted a retrospective cohort study and assessed treatment patterns, AEs, health-care resource use (HCRU), and costs in patients with diagnosis of CLL.

METHODS

Using a nationally representative population of privately insured patients in the US, adult patients with CLL diagnosis (July 2012-June 2015) were selected if they had continuous health plan enrollment for ≥12 months before the first CLL diagnosis without any evidence of any CLL-directed treatment. Treatment patterns up to four lines of therapy (LOT) and occurrence of AEs during CLL therapies were assessed. Mean per-patient monthly HCRU and costs were assessed overall and by number of unique AEs.

RESULTS

Of all patients meeting the selection criteria (n = 7,639; median age, 66 years), 18% (n = 1,379) received a systemic therapy during study follow-up. Of these, bendamustine/rituximab (BR) was the most common first observed regimen (28.1%), while ibrutinib was the most common therapy in the second (20.8%) and third (25.5%) observed regimens. The mean monthly all-cause and CLL-related costs, among patients treated with a systemic therapy, were $7,943 (SD = $15,757) and $5,185 (SD = $9,935), respectively. Mean monthly all-cause costs increased by the number of AEs (from $905 [SD = $1,865] among those with no AEs to $6,032 [SD = $13,290] among those with ≥6 AEs).

CONCLUSIONS

Chemoimmunotherapy, particularly BR, was the most common first observed therapy for CLL, whereas ibrutinib was most preferred in the second and third observed lines of therapy during the study period. Findings demonstrate that the economic burden of AEs in CLL is substantial.

Prognostic Factors in the Era of Targeted Therapies in CLL

PURPOSE OF REVIEW

Chronic lymphocytic leukemia is heterogeneous disease characterized by a variable clinical course that is greatly influenced by various patient and disease characteristics. Over the last two decades, advent of new diagnostic methodologies has led to the identification of several factors of prognostic and predictive relevance. Furthermore, recent advances in next-generation sequencing techniques has identified recurrent novel mutations in NOTCH1, SF3B1, BIRC3, and ATM genes whose role as prognostic and predictive markers is currently being investigated. These biologic markers carry new prognostic information and their incorporation into prognostic scoring systems will likely lead to refined multi-parameter risk models.

RECENT FINDINGS

While the prognostic impact of many of the most commonly used markers on clinical outcomes in patients treated with chemo-immunotherapy is well documented, it is important to review their predictive and prognostic role in the era of novel targeted therapies. This article will discuss the currently available information on the clinical relevance of prognostic markers in patients treated with novel targeted therapies.

Management of unfit elderly patients with chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a disease characterized by an increasing incidence with age reaching 35/100,000 in patients over 85 years. Elderly CLL patients carry several challenges, which have to be considered particularly in advanced stages including a higher risk of infections and individual differences in comorbidities and geriatric syndromes. Although no specific tool for geriatric evaluation in CLL has been developed so far, several of them (e.g. CIRS or Charlson-Score) have been tested in CLL patients. Several treatment options exist for frontline and relapse therapy in unfit CLL patients. Less intensive chemoimmunotherapy with engineered CD20 antibodies (e.g. obinutuzumab) is one of the treatment options, if TP53 mutation or deletion has been ruled out by genetic testing. Single agent treatment with the Btk-inhibitor ibrutinib is not only approved in relapsed CLL; but also for frontline therapy. The kinase inhibitor idelalisib (plus rituximab) and the bcl2 inhibitor venetoclax are other novel compounds, which showed great efficacy in relapsed CLL even in unfit patients. Treatment decisions in unfit patients have to take patient-related as well as disease-related risk factors into consideration.