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Long‐term data of chronic lymphocytic leukemia (CLL) patients with favorable risk who were treated with fludarabine, cyclophosphamide, and rituximab (FCR) within clinical trials show good efficacy. We here report long‐term data collected within the GCLLSG registry. Altogether, 417 CLL patients who received first‐line treatment with FCR were analyzed, of which 293 (70.3%) were treated outside of clinical trials. The median observation time from first‐line was 95.8 (interquartile range 58.7–126.8) months. Focusing on data of 194 (46.5%) patients who received FCR first‐line treatment after 2013 (start of data collection within GCLLSG registry), responses were documented in 85% of the patients, non‐responses in 15%, and for 3.6% the assessment was missing. Median event‐free survival (EFS, time until disease progression, subsequent treatment, or death) was 60.2 months with a 5‐year EFS‐rate of 50.6%. Patients with higher‐risk disease, characterized by unmutated IGHV (N = 78), had a median EFS of 45.4 months with a 5‐year EFS rate of 36.3%, while the median EFS was 77.5 months with a 5‐year EFS rate of 60.3% in patients with mutated IGHV (N = 40). Median overall survival was not reached with a 5‐year survival rate of 92.7%. In summary, first‐line FCR was associated with long EFS, especially in patients exhibiting a mutated IGHV status. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the safety and efficacy of different lenalidomide starting doses in patients with relapsed/refractory chronic lymphocytic leukemia (CLL). CLL patients were randomized to receive lenalidomide at initial doses of 5, 10, or 15 mg/d (N = 103). Doses were escalated by 5 mg every 28-d up to a maximum of 25 mg/d; dose reductions in up to 5 mg decrements were permitted. The most common grade ≥3 adverse events (AEs) were neutropenia and thrombocytopenia. Ten patients died during therapy (four deaths considered as related to lenalidomide); 12 patients experienced second primary malignancies. The most common cause for treatment discontinuation was AEs. Overall response rates were similar across arms. Progression-free survival and overall survival rates were longer in patients who escalated treatment (to 15 or 20 mg/d) versus those who did not. Lower starting doses allowed subsequent dose escalation of lenalidomide while maintaining an acceptable tolerability profile in patients with relapsed/refractory CLL.

Patients aged 80 years and older make up a fifth of patients with CLL but are underrepresented in clinical trials. We analyzed the outcomes of these patients treated with targeted agents in the front-line setting in six trials of the German CLL Study Group. Targeted agents included venetoclax, ibrutinib, and idelalisib, mainly used in combination with anti-CD20 antibodies. Among 716 patients, 33 matched the selection criteria (5%). Of those, the majority had relevant comorbidity, organ dysfunctions, and/or high-/very high-risk disease. The overall response rate was 73%. The median progression-free survival was 49.2 months compared with those not reached in younger patients. There were 11 documented deaths of which two were deemed related to therapy. Additional results including 40 patients treated with BTK-inhibitors from the GCLLSG registry suggest that treatment with targeted agents is feasible and effective. Dedicated studies are warranted for this particular subgroup of patients. [ABSTRACT FROM AUTHOR]

B‐cell receptor (BCR) signaling is central for the pathomechanism of chronic lymphocytic leukemia (CLL), and inhibitors of BCR signaling have substantially improved treatment options. To model malignant and nonmalignant BCR signaling, we quantified five components of BCR signaling (ZAP70/SYK, BTK, PLCγ2, AKT, ERK1/2) in single cells from primary human leukemic cells and from nonmalignant tissue. We measured signaling activity in a time‐resolved manner after stimulation with BCR crosslinking by anti‐IgM and/or anti‐CD19 and with or without inhibition of phosphatases with H2O2. The phosphorylation of BCR signaling components was increased in malignant cells compared to nonmalignant cells and in IGHV unmutated CLL cells compared to IGHV mutated CLL cells. Intriguingly, inhibition of phosphatases with H2O2 led to higher phosphorylation levels of BCR components in CLL cells with mutated IGHV compared to unmutated IGHV. We modeled the connectivity of the cascade components by correlating signal intensities across single cells. The network topology remained stable between malignant and nonmalignant cells. To additionally test for the impact of therapeutic compounds on the network topology, we challenged the BCR signaling cascade with inhibitors for BTK (ibrutinib), PI3K (idelalisib), LYN (dasatinib) and SYK (entospletinib). Idelalisib treatment resulted in similar effects in malignant and nonmalignant cells, whereas ibrutinib was mostly active on CLL cells. Idelalisib and ibrutinib had complementary effects on the BCR signaling cascade whose activity was further reduced upon dasatinib and entospletinib treatment. The characterization of the molecular circuitry of leukemic BCR signaling will allow a more refined targeting of this Achilles heel. [ABSTRACT FROM AUTHOR]

The type II anti-CD20 antibody obinutuzumab has structural and mechanistic features that distinguish it from the first anti-CD20 antibody, rituximab, which have translated into improved efficacy in phase III trials in indolent non-Hodgkin lymphoma and chronic lymphocytic leukemia (CLL). These gains have been shown through improvements in, and/or increased durability of, tumor response, and increases in progression-free survival in patients with CLL or follicular lymphoma (FL). Ongoing research is focusing on the use of biomarkers and the development of chemotherapy-free regimens involving obinutuzumab. phase II trials of such treatment regimens have shown promise for CLL, FL and mantle cell lymphoma, while phase III trials have highlighted obinutuzumab as the antibody partner of choice for novel agents in first-line CLL treatment. [ABSTRACT FROM AUTHOR]

Summary: Chronic lymphocytic leukaemia (CLL) is associated with alterations in T cell number, subset distribution and function. Among these changes, an increase in CD4+ T cells was reported. CD4+ T cells are a heterogeneous population and distinct subsets have been described to exert pro‐ and anti‐tumour functions. In CLL, controversial reports describing the dominance of IFNγ‐expressing Th1 T cells or of IL‐4‐producing Th2 T cells exist. Our study shows that blood of CLL patients is enriched in Th1 T cells producing high amounts of IFNγ. Moreover, we observed that their frequency remains relatively stable in CLL patients over a time course of five years. Furthermore, we provide evidence for an accumulation of Th1 T cells in the Eµ‐TCL1 mouse model of CLL. As TBET (encoded by Tbx21) is a crucial transcription factor for Th1 polarization, we generated Tbx21−/− bone marrow chimaeric mice which showed a lower number of IFNγ‐producing Th1 T cells, and used them for adoptive transfer of Eµ‐TCL1 leukaemia. Disease development in these mice was, however, comparable to that in wild‐type controls, excluding a major role for TBET‐expressing Th1 cells in Eµ‐TCL1 leukaemia. Collectively, our data highlight that Th1 T cells accumulate in CLL but reducing their number has no impact on disease development. [ABSTRACT FROM AUTHOR]

Summary: Clinical management of chronic lymphocytic leukaemia (CLL) in patients aged ≥80 years is based on limited evidence due to the lack of published information. Therefore, we analysed CLL patients aged ≥80 years using data from seven phase III clinical trials of the German CLL Study Group. Among 3552 participants, 152 were ≥80 years old at initiation of first‐line study treatment. Median age was 82 years (range 80–90). Concomitant diseases were present in 99% of the patients, with a median cumulative illness rating scale score of 8 (0–18). Chemoimmunotherapy with chlorambucil‐obinutuzumab (CLB‐OB) or chlorambucil‐rituximab (CLB‐R) was administered to 61 (40%) and 56 (37%) patients. The remaining patients received CLB (n = 19) or fludarabine (F, n = 10), F/cyclophosphamide (FC, n = 1), FC/rituximab (FCR, n = 2) or bendamustine/rituximab (BR, n = 3). Rates of grade 3 or 4 neutropenia and infections were 35% and 13%. Overall response rate was 77% with 13% complete remissions. Median progression‐free survival and treatment‐free survival were 17·2 and 32·3 months, respectively. Median overall survival was 48·3 months; adverse events (22%) and progressive CLL (16·4%) were the most frequent causes of death. These findings suggest that anti‐leukaemic treatment including chemoimmunotherapy is feasible and efficacious in ≥80‐year‐old CLL patients. However, this group of patients lives for a shorter time than age‐matched controls of the general population. [ABSTRACT FROM AUTHOR]

Aim: Four Phase II trials (clinical trials numbers: NCT02345863, NCT02401503, NCT02445131 and NCT02689141) evaluate a different combination of targeted agents in an all-comer population of approximately 60 patients with chronic lymphocytic leukemia irrespective of prior treatment, physical fitness and genetic risk factors. Patients with a higher tumor load start with a debulking treatment with bendamustine. The subsequent induction and maintenance treatment with an anti-CD20 antibody (obinutuzumab or ofatumumab) and a targeted oral agent (ibrutinib, idelalisib or venetoclax) are continued until achievement of a complete response and minimal residual disease negativity.Conclusion: This strategy represents a new era of chronic lymphocytic leukemia therapy where chemotherapy is increasingly replaced by targeted agents and treatment duration is tailored to the patient's individual tumor load and response. [ABSTRACT FROM AUTHOR]

Over the last few years, dramatic changes have occurred in the treatment of chronic lymphocytic leukemia (CLL). The current standard for young and fit patients with CLL remains chemoimmunotherapy, namely the fludarabine, cyclophosphamide, and rituximab (FCR) regimen. However, novel oral therapies are presently being introduced and represent a considerable breakthrough concerning effectiveness and safety profile. In particular, the very high-risk group of CLL patients, defined by the genetic aberration del(17p) and/or TP53 mutation, benefit from the new agents. These genetic abnormalities are the most relevant negative prognostic markers in the context of chemoimmunotherapy. New targeted therapies allow different approaches to improve outcomes. [ABSTRACT FROM AUTHOR]

Inhibitor of apoptosis (IAP) proteins are highly expressed in chronic lymphocytic leukemia (CLL) cells and contribute to evasion of cell death and poor therapeutic response. Here, we report that Smac mimetic BV6 dose-dependently induces cell death in 28 of 51 (54%) investigated CLL samples, while B-cells from healthy donors are largely unaffected. Importantly, BV6 is significantly more effective in prognostic unfavorable cases with, e.g., non-mutated VH status and TP53 mutation than samples with unknown or favorable prognosis. The majority of cases with 17p deletion (10/12) and Fludarabine refractory cases respond to BV6, indicating that BV6 acts independently of p53. BV6 also triggers cell death under survival conditions mimicking the microenvironment, e.g., by adding CD40 ligand or conditioned medium. Gene expression profiling identifies cell death, NF-κB and redox signaling among the top pathways regulated by BV6 not only in CLL but also in core-binding factor (CBF) acute myeloid leukemia (AML). Consistently, BV6 stimulates production of reactive oxygen species (ROS), which are contributing to BV6-induced cell death, since antioxidants reduce cell death. While BV6 causes degradation of cellular inhibitor of apoptosis (cIAP)1 and cIAP2 and nuclear factor-kappaB (NF-κB) pathway activation in primary CLL samples, BV6 induces cell death independently of caspase activity, receptor-interacting protein (RIP)1 activity or tumor necrosis factor (TNF)α, as zVAD.fmk, necrostatin-1 or TNFα-blocking antibody Enbrel fail to inhibit cell death. Together, these novel insights into BV6-regulated cell death in CLL have important implications for developing new therapeutic strategies to overcome cell death resistance especially in poor prognostic CLL subgroups. [ABSTRACT FROM AUTHOR]

Observation (watch and wait) is the standard of care for patients with asymptomatic Binet stage A chronic lymphocytic leukemia (CLL). However, the clinical course of these patients is very heterogeneous with some patients requiring treatment rather soon and others not progressing for ages. The clinical staging does not reflect this high variability of the clinical course of CLL. Published data demonstrate that the comprehensive use of several risk factors dramatically improves the accuracy of prognostication independent of clinical stage. The treatment of CLL underwent considerable changes with the introduction of kinase-inhibitors, including ibrutinib, an orally administered, well-tolerated and potent inhibitor of Bruton's tyrosine kinase. This is the first prospective, multicenter, placebo-controlled, double-blind, Phase III study to compare efficacy and safety of ibrutinib to a watch-and-wait approach in Binet stage A CLL with risk of disease progression defined by the comprehensive CLL score. [ABSTRACT FROM AUTHOR]

Abstract: Recurrent losses or gains of genomic material as well as mutations of key tumor suppressors (ATM and TP53) have been identified in chronic lymphocytic leukemia (CLL). These aberrations are important “drivers” of the disease and some of its clinical characteristics. There is a remarkable heterogeneity in the clinical course between patient subgroups with distinct genetic features. While some mutations are associated with poor outcome (particularly 17p− and TP53 mutation and to a lesser extend 11q−) others are linked to a favorable outcome (13q− as sole aberration; mutated IGHV). Our improved understanding of the clinical course of specific genetic subgroups is beginning to be translated into genotype specific treatment approaches where genetic subgroups (e.g. 17p−) are channeled into separate treatment protocols. This review will summarize the most important genetic aberrations in CLL and how our improved knowledge of the genetic make-up of leukemic cells may translate into improved treatment results. [Copyright &y& Elsevier]

The article reports on a study analyzing the mutations of the TNFAIP3 (A20) tumor suppressor gene in chronic lymphocytic leukemia (CLL), which is the most common leukemia in adults of the Western countries. In the study, 48 CLL, including at least 12 cases with a deletion of one allele of TNFAIP3, were analyzed. The study found that A20 inactivation plays no significant role in the pathogenesis of CLL.

The article discusses the study on the presence of activating mutations in spleen tyrosine kinase (SYK) that contribute to improved B-cell receptor (BCR) signaling in patients with chronic lymphocytic leukemia (CLL). It states that the investigation describe mutations in the region of protein coding of SYK that could contribute to the pathogenesis of CLL. It mentions that the gain-of-function point mutation was not the caused of improved SYK kinase activity.

Many prognostic factors have been identified in chronic lymphocytic leukaemia (CLL). Based on the assessment of B cell receptor (BCR) structure and function, a subdivision into subtypes is possible (e.g., immunoglobulin heavy chain variable gene segment (IGHV) unmutated and mutated, V3-21 usage) with distinct biological and clinical characteristics. Recurrent genomic aberrations (i.e., 11q and 17p deletion) and gene mutations (i.e., TP53 and ATM) help to define biological and clinical subgroups. In addition, serum markers (e.g., thymidine kinase (TK) and ß2-microglobulin (ß2-MG)), cellular markers (e.g., CD38 and ZAP70) and clinical staging have an impact on outcome in CLL. The biological characterisation of CLL has not only led to progress in outcome prediction but also has begun to be translated into novel treatment strategies. Nonetheless, most factors associated with prognosis have not been thoroughly interrogated for their predictive value in the light of different therapeutic approaches. With a growing number of agents acting on specific biological targets and being used in different clinical situations, the future is likely to bring the identification of predictive factors in CLL. [Copyright &y& Elsevier]

Loss of a critical region in 13q14.3 [del(13q)] is the most common genomic aberration in chronic lymphocytic leukemia (CLL), occurring in more than 50% of patients (Stilgenbauer et al., Oncogene 1998;16:1891 - 1897, Dohner et al., N Engl J Med 2000;343:1910 - 1916). Despite extensive investigations, no point mutations have been found in the remaining allele that would inactivate one of the candidate tumor suppressor genes and explain the pathomechanism postulated for this region. However, the genes in the region are significantly down-regulated in CLL cells, more than would be expected by gene dosage, and recently a complex epigenetic regulatory mechanism was identified for 13q14.3 in non-malignant cells that involves asynchronous replication timing and monoallelic expression of candidate tumor suppressor genes. Here, we propose a model of a multigenic pathomechanism in 13q14.3, where several tumor suppressor genes, including the miRNA genes miR-16-1 and miR-15a, are co-regulated by the two long non-coding RNA genes DLEU1 and DLEU2 that span the critical region. Furthermore, we propose these co-regulated genes to be involved in the same molecular pathways, thereby also forming a functional gene cluster. Elucidating the molecular and cellular function of the 13q14.3 candidate genes will shed light on the underlying pathomechanism of CLL. [ABSTRACT FROM AUTHOR]

The importance of studying p53 pathway defects in chronic lymphocytic leukemia (CLL) has been promoted by the demonstration of the fundamentally different clinical course of patients with 17p deletion. The observation of resistance to chemotherapy and mutation of the remaining TP53 allele explain the clinical presentation of CLL with 17p deletion. Here we review recent evidence that cases with TP53 mutation in the absence of the deletion of 17p have a similar clinical and biological course as cases carrying the deletion 17p. In addition, other principal components of the DNA damage pathway reportedly are de-regulated by mutation (ATM), deletion (ATM) or potentially more complex down-regulation (miR-34a) in CLL. Nonetheless, challenges remain because we can only explain resistance in a proportion of the cases that are resistant to first line treatment. This is of particular practical interest because our armamentarium of drugs in clinical use that acts independent of the DNA damage pathway is growing, for example antibody-based treatment (alemtuzumab), immuno-modulating drugs (lenalidomide), CDK inhibitors (flavopiridol) and steroids. [ABSTRACT FROM AUTHOR]

The clinical staging systems developed by Rai and Binet have remained the mainstay for clinical decision-making in patients with chronic lymphocytic leukemia (CLL). However, there is substantial heterogeneity in the course of the disease. In recent years molecular and cellular markers have helped to predict the prognosis of patients with CLL. Ig VH status and genomic aberrations subdivide CLL into distinct clinical subgroups. Fluorescence in-situ hybridization (FISH) can identify genomic aberrations in approximately 80% of CLL cases. The most frequent aberrations are deletions in 13q, 11q, or 17p, and trisomy 12. Apart from providing insights into the pathogenesis, genomic aberrations identify subgroups of patients with distinct clinical pictures: lymphadenopathy (11q–) or resistance to therapy (17p–). Deletions at 11q and particularly 17p are associated with rapid disease progression or inferior survival. Patients with these genetic abnormalities may be candidates for clinical trials investigating alternative treatments and stem-cell transplantation. [Copyright &y& Elsevier]

AbstractIn chronic lymphocytic leukemia (CLL), TP53 mutations or deletions on chromosome 17p lead to adverse prognosis and reduced levels of miR-34a, which targets NOTCH1. Also, hyperactivated NOTCH1 signaling is crucial for CLL progression. Here we explored the interaction between p53, miR-34a, and NOTCH1 in CLL. We investigated the effect of p53 and miR-34a on NOTCH1 signaling and expression in CLL cells with altered TP53. Our results indicate that miR-34a reduces NOTCH1 3’ UTR activity but might not be a mediator between p53 signaling and NOTCH1. p53 activation increases miR-34a expression and NOTCH1 protein levels, correlating with decreased NOTCH1 and miR-34a levels in primary CLL cells with TP53 alterations. Some samples with high NOTCH1 levels presented increased BCL-2, suggesting an anti-apoptotic mechanism of a potentially direct p53-NOTCH1 relation in CLL. This study deepens the understanding of the p53-miR-34a-NOTCH1 signaling network, providing insights that could guide future therapeutic strategies for CLL. [ABSTRACT FROM AUTHOR]

Updated results of the CLL8 trial confirm that the addition of rituximab to chemotherapy with fludarabine and cyclophosphamide (FC) leads to a prolongation of progression-free (PFS) and overall survival (OS) in first-line treatment of physically fit patients. After a median observation time of 47 months, median PFS was 57.9 months for patients treated with FC and rituximab (FCR) and 32.9 months for patients treated with FC alone (hazard ratio 0.56, 95% confidence interval 0.465-0.673; p < 0.001). A total of 232 patients were treated for relapse, among them 91 of 408 (22%) initially treated with FCR and 141 of 409 (35%) initially treated with FC. The drugs most frequently used either alone or in combination were rituximab (52% of all second-line therapies), fludarabine (21%), bendamustine (21%) and alemtuzumab (12%). The regimens chosen for second-line treatment after FC or FCR were heterogeneous, which underlines a need for further trials in order to define treatment recommendations for patients with relapsed chronic lymphocytic leukemia. [ABSTRACT FROM AUTHOR]

The advent of highly effective treatments targeting the disease biology of chronic lymphocytic leukemia (CLL) has transformed the therapeutic field tremendously. However, transformation into an aggressive B-cell lymphoma, called Richter syndrome (RS), remains highly challenging since the treatment options for this condition are still insufficient. Exploratory drug testing and experimental studies are restricted by the lack of satisfactory models. We have established U-RT1, a cell line derived from a highly proliferating RS clonally related to the patient's underlying CLL. The cell line shows morphological features and an immunophenotype of RS-DLBCL (non-GCB). Molecular analysis revealed a complex karyotype with driver aberrations characteristic for RS such as loss of TP53 and CDKN2A. Furthermore, U-RT1 displays a chromosomal gain of the NOTCH1 gene locus and strong immunoreactivity for BCL-2. These features suggest that U-RT1 is the first eligible model system for investigations on the pathogenesis of RS and novel treatment options. [ABSTRACT FROM AUTHOR]

T cell exhaustion limits anti-tumor immunity and responses to immunotherapy. Here, we explored the microenvironmental signals regulating T cell exhaustion using a model of chronic lymphocytic leukemia (CLL). Single-cell analyses identified a subset of PD-1hi, functionally impaired CD8+ T cells that accumulated in secondary lymphoid organs during disease progression and a functionally competent PD-1int subset. Frequencies of PD-1int TCF-1+ CD8+ T cells decreased upon Il10rb or Stat3 deletion, leading to accumulation of PD-1hi cells and accelerated tumor progression. Mechanistically, inhibition of IL-10R signaling altered chromatin accessibility and disrupted cooperativity between the transcription factors NFAT and AP-1, promoting a distinct NFAT-associated program. Low IL10 expression or loss of IL-10R-STAT3 signaling correlated with increased frequencies of exhausted CD8+ T cells and poor survival in CLL and in breast cancer patients. Thus, balance between PD-1hi, exhausted CD8+ T cells and functional PD-1int TCF-1+ CD8+ T cells is regulated by cell-intrinsic IL-10R signaling, with implications for immunotherapy. [Display omitted] • Heterogeneous PD-1 expression identifies CD8+ T cells with distinct functions in CLL • IL-10 prevents activation-induced exhaustion of CD8+ T cells and reduces CLL development • By altering chromatin in CD8+ T cells, IL-10R blockade disrupts NFAT:AP-1 cooperativity • IL-10R loss correlates with T cell exhaustion and poor survival of cancer patients T cell exhaustion limits anti-tumor immunity and responses to immunotherapy. Using a model of chronic lymphocytic leukemia, Hanna, Llaó-Cid, et al. reveal that the balance between PD-1hi, exhausted CD8+ T cells and functional PD-1int CD8+ T cells that are associated with tumor progression or tumor control, respectively, is regulated by cell-intrinsic IL-10R signaling. [ABSTRACT FROM AUTHOR]