Frontline low-dose alemtuzumab with fludarabine and cyclophosphamide prolongs progression-free survival in high-risk CLL

Establishment of a primary renal lymphoma model and its clinical relevance

Extranodal dissemination is an important feature of aggressive B-cell lymphoma. Owing to the lack of available animal models, the study on extranodal dissemination of lymphoma is greatly limited. Here, we identified a novel cell line, named MA-K, which originated from the Eμ-Myc;Cdkn2a-/- cell line, named MA-LN in this study. Compared to MA-LN, MA-K tended to disseminate in the kidney rather than the lymph nodes in the lymphoma transplantation model, resembling human primary renal lymphoma. The transcriptome analysis revealed that MA-K had undergone transcriptional evolution during the culture. The specialized transcriptional pattern analysis we proposed in this study identified that the FOXO1-BTG1-MYD88 pattern was formed in MA-K. Further analysis found that the translation pathway was the most enriched pathway in specially expressed genes (SEGs) in MA-K. Among the SEGs, three upregulated genes, RPLP2, RPS16, and MRPS16, and five downregulated genes, SSPN, CD52, ANKRD37, CCDC82, and VPREB3, in MA-K were identified as promising biomarkers to predict the clinical outcomes of human DLBCL. Moreover, the joint expression of the five-gene signature could effectively predict clinical outcomes of human DLBCL in three groups. These findings suggested that the MA-K cell line had strong clinical relevance with human aggressive B-cell lymphoma. Moreover, the MA-K primary renal lymphoma model, as a novel syngenetic mouse model, will be greatly useful for both basic research on lymphoma dissemination and preclinical efficacy evaluation of chemotherapy and immunotherapy.

Targeted therapies in CLL/SLL and the cumulative incidence of infection: A systematic review and meta-analysis

Background: Patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) are prone to infections.

Aims: Provide a pooled estimate of the cumulative incidence for infections that fulfilled the criteria associated with severe infectious adverse events for grade 3 or higher (including pneumonia, febrile neutropenia and sepsis) in patients who receive targeted therapies.

Methods: We searched PubMed and EMBASE for randomized controlled trials (RCT) that included patients with CLL/SLL who received targeted therapies and performed a random-effects meta-analysis to estimate the cumulative incidence of infections.

Results: Of 2,914 studies screened, we retrieved 31 which evaluated 11,660 patients. The pooled cumulative incidence of infections for patients who received treatment regimens based on a BTK inhibitors was 19.86%. For patients who received treatment based on rituximab and second generation anti-CD20 monoclonal antibodies, the pooled cumulative incidence of infections was 19.85 and 13.46%, respectively. Regarding PI3K inhibitor-based regimens the cumulative incidence of severe infections was 30.89%. BCL-2 inhibitors had a cumulative incidence of infections of 17.49% while lenalidomide and alemtuzumab had an incidence of 13.33 and 45.09%, respectively. The cumulative incidence of pneumonia ranged from 3.01 to 8.45% while febrile neutropenia ranged from 2.68 to 10.80%. Regarding sepsis, the cumulative incidence ranged from 0.9 to 4.48%.

Conclusion: Patients with CLL/SLL who receive targeted therapies may develop severe infections at significant rates that, in addition to disease stage and other complications, depend on the mechanism of action of the used drug. Surveillance for infections and development of effective prophylactic strategies are critical for patients with CLL/SLL who receive targeted therapies.

Systematic Review Registration: [https://systematicreview.gov/], identifier [registration number]

Survival, causes of death, and the prognostic role of comorbidities in chronic lymphocytic leukemia in the pre-ibrutinib era: A population-based study

OBJECTIVE

To evaluate temporal trends in survival and causes of death in patients with chronic lymphocytic leukemia (CLL) in a nationwide study.

METHODS

The cohort consisted of 13,009 Swedish CLL patients diagnosed 1982-2013. Relative survival (RS) and excess mortality rate ratios (EMRR) with 95% confidence intervals (95% CIs) were estimated using flexible parametric survival models. Cause-specific hazard ratios (HRs) were estimated for the linear effect of 10-year increase in year of diagnosis.

RESULTS

The excess mortality decreased comparing 2003-2013 to 1982-1992 (EMRR = 0.53, 95% CI 0.48-0.58). The 5-year RS increased between 1982 and 2012 for patients >51 years at diagnosis and improved for patients ≤51 years after 2002. The rate of CLL-specific deaths decreased over time (HR = 0.78, 95% CI 0.75-0.81). Compared to patients with no comorbidity, patients with 1 and 2+ Charlson Comorbidity Index points had HR = 1.35 (95% CI 1.25-1.45) and HR = 1.47 (95% CI 1.37-1.57) for CLL-related mortality, respectively.

CONCLUSION

Survival in CLL patients improved in the era of chemoimmunotherapy, and this was largely explained by reduced CLL-related mortality. The increased rate of CLL-related mortality in patients with comorbidities emphasizes the importance of the newer and better tolerated targeted therapy.

Transformation to plasmablastic lymphoma in CLL upon ibrutinib treatment

Chronic lymphatic leukaemia (CLL) is the most common leukaemia in the Western world. Ibrutinib, a tyrosine kinase inhibitor, is the treatment of choice on relapse or p53-dysfunction. Richter's transformation to diffuse large B cell lymphoma is most often seen. However, transformation to other aggressive lymphomas as plasmablastic lymphoma (PBL) does occur. PBL is an extremely aggressive lymphoma and is usually treated using a CHOP-like regimen (cyclophosphamide, doxorubicin, vincristine and prednisone/dexamethasone), but with poor outcome. The only curative treatment is allogeneic stem cell transplant (ASCT).We report on a case of CLL treated with ibrutinib that underwent transformation to PBL. Due to high expression of CD138, we added daratumumab to the chemotherapy with a good, but transitory response. The case did not make it to an ASCT. Targeting CD138 by daratumumab may be added to chemoimmune therapy for PBL.

Trial watch: chemotherapy-induced immunogenic cell death in immuno-oncology

The term ‘immunogenic cell death’ (ICD) denotes an immunologically unique type of regulated cell death that enables, rather than suppresses, T cell-driven immune responses that are specific for antigens derived from the dying cells. The ability of ICD to elicit adaptive immunity heavily relies on the immunogenicity of dying cells, implying that such cells must encode and present antigens not covered by central tolerance (antigenicity), and deliver immunostimulatory molecules such as damage-associated molecular patterns and cytokines (adjuvanticity). Moreover, the host immune system must be equipped to detect the antigenicity and adjuvanticity of dying cells. As cancer (but not normal) cells express several antigens not covered by central tolerance, they can be driven into ICD by some therapeutic agents, including (but not limited to) chemotherapeutics of the anthracycline family, oxaliplatin and bortezomib, as well as radiation therapy. In this Trial Watch, we describe current trends in the preclinical and clinical development of ICD-eliciting chemotherapy as partner for immunotherapy, with a focus on trials assessing efficacy in the context of immunomonitoring.

Pentostatin, Cyclophosphamide, and Rituximab Followed by Alemtuzumab for Relapsed or Refractory Chronic Lymphocytic Leukemia: A Phase 2 Trial of the ECOG-Acrin Cancer Research Group (E2903)

Patients with relapsed/refractory (R/R) chronic lymphocytic leukemia (CLL) may benefit from salvage chemoimmunotherapy (CIT). To explore further the use of CIT in the pre-novel agent era, ECOG-ACRIN undertook a phase 2 trial (E2903) for R/R CLL utilizing pentostatin, cyclophosphamide, and rituximab (PCR) followed by a consolidation course of alemtuzumab. This trial enrolled 102 patients with a median age of 64 years. Treatment consisted of 6 cycles of PCR followed by alemtuzumab for either 4 or 18 weeks depending on the initial response to PCR. The overall response after PCR (complete remission, CR, nodular partial remission, nPR, and partial remission, PR) was 55%. Major responses (CR or nPR) were achieved in 6%. The median overall survival (OS) and the median progression-free survival were 28 and 12 months, respectively. The most serious nonlethal adverse events were myelosuppression, febrile neutropenia, fatigue, nausea, and hyponatremia. PCR is an effective and well-tolerated nucleoside-based regimen for heavily pretreated CLL patients with R/R disease. The addition of alemtuzumab to CLL patients with a minor response (PR) or stable disease did not result in a significant number of higher responses (CR or nPR) nor an improvement in OS.

Mechanisms of Resistance to Targeted Therapies in Chronic Lymphocytic Leukemia

Even if treatment options for Chronic Lymphocytic Leukemia (CLL) patients have changed dramatically in the past few years, with the approval of targeted therapeutic agents, the disease remains incurable. Beside intrinsic genetic features characterizing the leukemic cell, signals coming from the microenvironment have a key role in promoting cell survival and in protecting CLL cells from the action of drugs. Consequently, the identification of previously unrecognized genetic lesions is important in risk-stratification of CLL patients and is progressively becoming a critical tool for choosing the best therapeutic strategy. Significant efforts have also been dedicated to define microenvironment-dependent mechanisms that sustain leukemic cells favoring survival, proliferation, and accumulation of additional genetic lesions. Furthermore, understanding the molecular and biological mechanisms, potentially driving disease progression and chemoresistance, is the first step to design therapies that could be effective in high-risk patients. Significant progress has been made in the identification of the different mechanisms through which patients relapse after "new" and "old" therapies. These studies have led to the development of targeted strategies to overcome, or even prevent, resistance through the design of novel agents or their combination.In this chapter we will give an overview of the main therapeutic options for CLL patients and review the mechanisms of resistance responsible for treatment failure. Potential strategies to overcome or prevent resistance will be also discussed.

Canadian evidence-based guideline for the first-line treatment of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (cll) is the most common adult leukemia in North America. In Canada, no unified national guideline exists for the front-line treatment of cll; provincial guidelines vary and are largely based on funding. A group of clinical experts from across Canada developed a national evidence-based treatment guideline to provide health care professionals with clear guidance on the first-line management of cll. Consensus recommendations based on available evidence are presented for the first-line treatment of cll.

Immunogenic cell death in anticancer chemotherapy and its impact on clinical studies

The traditional view holds that apoptosis is non-immunogenic and does not induce an inflammatory response. However, recent studies have suggested that certain chemotherapeutic drugs that induce tumor cell apoptosis can induce immunogenic cell death (ICD) in cancer cells. This process is characterized by not only up-regulation of a series of signaling molecules in cancer cells, including expose of calreticulin (CRT), secretion of adenosine triphosphate (ATP) and release of high mobility group box 1 (HMGB1). In this review, we summarize recent progress in identifying and classifying ICD inducers; concepts and molecular mechanisms of ICD; and the impact and potential applications of ICD in clinical studies. We also discuss the contributions of ICD inducers in combination with other anticancer drugs in clinical applications.

Trial watch: Immunogenic cell death induction by anticancer chemotherapeutics

The expression "immunogenic cell death" (ICD) refers to a functionally unique form of cell death that facilitates (instead of suppressing) a T cell-dependent immune response specific for dead cell-derived antigens. ICD critically relies on the activation of adaptive responses in dying cells, culminating with the exposure or secretion of immunostimulatory molecules commonly referred to as "damage-associated molecular patterns". Only a few agents can elicit bona fide ICD, including some clinically established chemotherapeutics such as doxorubicin, epirubicin, idarubicin, mitoxantrone, bleomycin, bortezomib, cyclophosphamide and oxaliplatin. In this Trial Watch, we discuss recent progress on the development of ICD-inducing chemotherapeutic regimens, focusing on studies that evaluate clinical efficacy in conjunction with immunological biomarkers.

Direct targeting of cancer cells with antibodies: What can we learn from the successes and failure of unconjugated antibodies for lymphoid neoplasias?

Following approval in 1997 of the anti-CD20 antibody rituximab for the treatment of B-NHL and CLL, many other unconjugated IgG1 MAbs have been tested in pre-clinical and clinical trials for the treatment of lymphoid neoplasms. Relatively few have been approved however and these are directed against a limited number of target antigens (CD20, CD52, CCR4, CD38, CD319). We review here the known biological properties of these antibodies and discuss which factors may have led to their success or may, on the contrary, limit their clinical application. Common factors of the approved MAbs are that the target antigen is expressed at relatively high levels on the neoplastic targets and their mechanism of action is mostly immune-mediated. Indeed most of these MAbs induce ADCC and phagocytosis by macrophages, and many also activate complement, leading to target cell lysis. In contrast direct cell death induction is not a common feature but may enhance efficacy in some cases. Interestingly, a key factor for the success of several MAbs appears to be their capacity to skew immunity towards an anti-tumour mode, by inhibiting/depleting suppressor cells and/or activating immune cells within the microenvironment, independently of FcγRs. We also expose here some of the strategies employed by industry to expand the clinical use of these molecules beyond their original indication. Interestingly, due to the central role of lymphocytes in the control of the immune response, several of the antibodies are now successfully used to treat many different autoimmune diseases and have also been formally approved for some of these new indications. There is little doubt that this trend will continue and that the precise mechanisms of therapeutic MAbs will be further dissected and better understood in the context of both tumour immunology and autoimmunity.

Treatment of Del17p and/or aberrant TP53 chronic lymphocytic leukemia in the era of novel therapies

More effective therapies are emerging, with better toxicity profiles, and are being incorporated into modern treatment algorithms of chronic lymphocytic leukemia at various stages of the disease, including for patients harboring Del17p and/or aberrant TP53. Ibrutinib, an inhibitor of Bruton's tyrosine kinase, has demonstrated impressive response rates in the relapsed/refractory setting, including in the setting of Del17p and/or TP53 mutations. Venetoclax, an inhibitor of BCL-2 known to play an important role in regulating cell death, has been approved recently for treatment of patients with chronic lymphocytic leukemia with Del17p who have received at least one prior therapy. Unfortunately, a cure remains unattainable unless eligible patients are offered an allogeneic hematopoietic cell transplant. However, hematopoietic cell allografting is limited by the availability of suitable donors and significant morbidity and mortality. Recent clinical practice recommendations by the American Society for Blood and Marrow Transplantation have relegated the role of transplantation to later stages of the disease. In patients with evidence of Richter syndrome, frontline consolidation allogeneic hematopoietic cell transplantation remains the most desirable approach owing to the limited activity of ibrutinib or other novel therapies. Further therapeutic advances would require enrolling these patients in large clinical trials that evaluate novel therapies alone or in combination with traditional chemotherapies or even in the setting of posttransplant consolidation/maintenance.

Soluble CD52 is an indicator of disease activity in chronic lymphocytic leukemia

CD52 is a glycoprotein expressed on normal as well as leukemic immune cells and shed as soluble CD52 (sCD52). We studied sCD52 levels in three CLL cohorts: the 'early', the 'high-risk', and the 'ibrutinib-treated'. The 'high-risk' patients had significantly higher sCD52 levels than the 'early' patients. For the 'early' patients, high sCD52 levels were associated with a significantly shorter time to first treatment. Regarding prognostic factors, no clear correlations with stage, IGHV, or beta-2-microglobulin were found; in a cox multivariate analysis of the 'early' patients, sCD52 and IGHV both had independent prognostic value. Following chemo-immunotherapy, sCD52 decreased in parallel with leukocytes while during ibrutinib treatment and ibrutinib-induced ymphocytosis, sCD52 decreased along with lymph node reductions. In vitro IgM stimulation of CLL cells led to increased sCD52 levels in the medium. Our findings indicate that sCD52 reflects disease activity and potentially treatment efficacy in CLL.

The safety profile of monoclonal antibodies for chronic lymphocytic leukemia

INTRODUCTION

Monoclonal antibodies (MoAbs), non-chemotherapeutic agents targeting the antigens present on chronic lymphocytic leukemia (CLL) lymphocytes, are being implemented increasingly more often as treatment options. Areas covered: This article reviews the similarities and differences in the structure, mechanism of action, efficacy and safety profile of commercially-available MoAbs and prevents new agents potentially useful for CLL treatment. Publications in English before June 2016 were surveyed on the MEDLINE database for articles. Proceedings of the American Society of Hematology held during the last five years were also included. Expert opinion: MoAbs, especially those targeting CD20, are highly effective biological options for first-line and salvage treatment of CLL, particularly in chemoimmunotherapy, and possibly also as maintenance therapy. Treatment with MoAbs is associated with reduced risk of such adverse events as cytopenias, infections and secondary neoplasias and is generally well tolerated. Depending on antibody type, the most common adverse events are usually transient and limited to grade 1 and 2 infusion-related reactions. In addition to commercially available MoAbs, several other antibodies exist which are targeted against different antigens studied in the clinical trials.

Sequencing of chronic lymphocytic leukemia therapies

It is an unprecedented time for the treatment of patients with chronic lymphocytic leukemia (CLL) with the recent approval of several targeted agents for use in frontline, relapsed, refractory, and high-risk disease. Traditionally, frontline management of CLL has been a combination of chemotherapy (fludarabine, cyclophosphamide, bendamustine, or chlorambucil) with an anti-CD20 monoclonal antibody (rituximab, ofatumumab, obinutuzumab). The current landscape is rapidly evolving with the advent of therapies that demonstrate selective inhibition of important pathways necessary for CLL proliferation and survival. Despite considerable progress, much is still unknown and optimal treatment selection and sequence is still debatable. None of the new agents have been compared against each other and the impact of adding an additional agent to monotherapy is not yet fully elucidated. In routine clinical practice, the choice of therapy is based on nonrandomized comparisons, presence of comorbidities, and toxicity considerations. These recently approved drugs (ibrutinib, idelalisib, and venetoclax) are reporting excellent outcomes, including patients with high-risk disease such as 17p deletion (17p-) or TP53 mutations (TP53mut). Ibrutinib and venetoclax have been approved for use in 17p- patients (frontline and relapsed, respectively). Ibrutinib is currently moving into the frontline space given recent regulatory approvals. This review will summarize and interpret the limited therapeutic sequencing data available, highlighting the need for additional studies to optimize combination strategies and treatments after failure or discontinuation of these novel agents.

National trends in incidence and survival of chronic lymphocytic leukemia in Norway for 1953-2012: a systematic analysis of population-based data

Chronic lymphocytic leukemia is a disease of the elderly, and despite major advances in treatment, remains incurable. The Cancer Registry of Norway has registered data on patients with chronic lymphocytic leukemia since 1953. We aimed to analyze trends in incidence and survival of chronic lymphocytic leukemia in Norway. We identified 7664 patients reported with chronic lymphocytic leukemia to the registry between 1953 and 2012. We gathered information on sex, age at diagnosis, date of death and basis for diagnosis. The age‐standardized incidence increased from 0.6/100.000 person‐years in 1953 to 3.1/100,000 person‐years in 2012. We found a significant decrease in median age between 1993–2002 and 2003–2012 (75 vs. 72 years, 95%CI: 2.52–3.98, P < 0.001). Men were diagnosed at a significantly younger age than women. Immunophenotyping has become the most important diagnostic method after 2002. Median observed survival increased from 3 years in 1952–1963 to 8.5 years in 2003–2012. Five‐ and 10‐year age‐standardized net survival increased throughout the whole period across age groups and reached 79% and 57%, respectively. Median observed survival was significantly shorter in men than in women in 1993–2002 (4.9 vs. 6.1 years, P < 0.001). The gap between survival rates for men and women was diminishing in 2003–2012 in patients younger than 60 years while it remained considerable in older patients. Despite an aging Norwegian population, chronic lymphocytic leukemia (CLL) patients become younger at diagnosis. A fourfold increase in incidence, a prolonged survival, and major changes in diagnostic methods in Norway were observed.

TP53 dysfunction in CLL: Implications for prognosis and treatment

Despite the availability of novel targeted agents, TP53 defects remain the most important adverse prognostic factor in chronic lymphocytic leukemia (CLL). Detection of deletion of TP53 locus (17p deletion) by fluorescent in situ hybridization (FISH) has become standard and performed prior to every line of treatment as the incidence dramatically increases as relapses occur. As monoallelic mutations of TP53 equally affect outcome, novel methods are being developed to improve detection of TP53 defects and include next-generation sequencing (NGS) and functional assays. TP53 defects highly affect outcome of immunochemotherapy but also alter response durations of tyrosine kinase inhibitors. Although BCR-targeting agents and Bcl-2-inhibitos have achieved durable responses in some patients with TP53 defects, long-term follow-up is currently lacking. In this review biological and clinical consequences of TP53 dysfunction as well as applicability of currently available methods to detect TP53 defects are described. In addition, proposed novel therapeutic strategies specifically for patients with TP53 dysfunction are discussed. In summary, the only curative treatment option for TP53-defective CLL is still allogeneic hematopoietic stem cell transplantation. Other treatment strategies such as rationale combinations of agents with different (TP53 independent) targets, including kinase inhibitors and inhibitors of anti-apoptotic molecules but also immunomodulatory agents need to be further explored.

The HOVON68 CLL trial revisited: performance status and comorbidity affect survival in elderly patients with chronic lymphocytic leukemia

In the HOVON68 CLL trial, patients 65 to 75 years of age had no survival benefit from the addition of low-dose alemtuzumab to fludarabine and cyclophosphamide (FC) in contrast to younger patients. The reasons are explored in this 5-year trial update using both survival analysis and competing risk analysis on non-CLL-related mortality. Elderly FCA patients died more frequently from causes not related to CLL, and more often related to comorbidity (mostly cardiovascular) than to infection. In a Cox multivariate analysis, del(17p), performance status >0, and comorbidity were associated with a higher non-CLL-related mortality in the elderly independent of the treatment modality. Thus, while the 'fit' elderly with no comorbidity or performance status of 0 might potentially benefit from chemo-immunotherapy with FC, caution is warranted, when considering alemtuzumab treatment in elderly patients with cardiovascular comorbidity.

Initial therapy of chronic lymphocytic leukemia

Only chronic lymphocytic leukemia (CLL) patients with active or symptomatic disease or with advanced Binet or Rai stages require therapy. Prognostic risk factor profile and comorbidity burden are most relevant for the choice of treatment. For physically fit patients, chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab remains the current standard therapy. For unfit patients, treatment with an anti-CD20 antibody (obinutuzumab or rituximab or ofatumumab) plus milder chemotherapy (chlorambucil) may be applied. Patients with a del(17p) or TP53 mutation should be treated with the kinase inhibitors ibrutinib or a combination of idelalisib and rituximab. Clinical trials over the next several years will determine, whether kinase inhibitors, other small molecules, immunotherapeutics, or combinations thereof will further improve outcomes for patients with CLL.

Targeted therapies for CLL: Practical issues with the changing treatment paradigm

Chemoimmunotherapy (CIT) such as FCR (fludarabine, cyclophosphamide, rituximab) has been the standard first-line therapy for younger patients with CLL. In the last few years, several novel targeted therapies have been developed for patients with CLL. These include B-cell receptor (BCR) inhibitors such as Bruton tyrosine kinase (BTK) inhibitors, PI3 kinase inhibitors, and Syk inhibitors, novel anti-CD20 monoclonal antibodies such as ofatumumab and obinutuzumab, and Bcl-2 antagonists such as venetoclax (ABT-199). Strategies targeting the immune system such as lenalidomide, chimeric antigen receptor (CAR) T cells, and more recently, checkpoint inhibitors, are in clinical development. Ibrutinib and idelalisib are already approved for patients with relapsed and refractory CLL. Ibrutinib is also approved for first-line treatment of CLL patients with del(17p). Several ongoing phase III clinical trials with novel therapies will further define the role of targeted agents in CLL.

Advances in first-line treatment of chronic lymphocytic leukemia: current recommendations on management and first-line treatment by the German CLL Study Group (GCLLSG)

The management of patients with CLL is undergoing significant changes; during the last decade, the outcome of first-line therapies has been markedly improved with the addition of anti-CD20 antibodies to chemotherapy. Today, chemoimmunotherapy for physically fit patients ≤ 65 years should consist of fludarabine, cyclophosphamide, and rituximab (FCR). The combination of bendamustine and rituximab (BR) should be considered in physically fit patients > 65 years and in patients with a higher risk of infections. Patients with reduced fitness and/or relevant comorbidity should receive chlorambucil with a CD20 antibody, preferably obinutuzumab. Regardless of their fitness, patients with CLL carrying genetic aberrations such as del(17p) and/or TP53 mutation poorly respond to chemoimmunotherapy and therefore require different therapeutic approaches. An increasing understanding of the disease biology has led to the development of targeted drugs for the treatment of CLL, such as the BTK inhibitor ibrutinib and PI3K inhibitor idelalisib. These agents have shown efficacy in high-risk and relapsed/refractory patients and are currently being evaluated in clinical trials for first-line therapy. It is anticipated that these compounds and further other novel agents will profoundly change the therapy of CLL.

Assessment of p53 and ATM functionality in chronic lymphocytic leukemia by multiplex ligation-dependent probe amplification

The ATM-p53 DNA-damage response (DDR) pathway has a crucial role in chemoresistance in CLL, as indicated by the adverse prognostic impact of genetic aberrations of TP53 and ATM. Identifying and distinguishing TP53 and ATM functional defects has become relevant as epigenetic and posttranscriptional dysregulation of the ATM/p53 axis is increasingly being recognized as the underlying cause of chemoresistance. Also, specific treatments sensitizing TP53- or ATM-deficient CLL cells are emerging. We therefore developed a new ATM-p53 functional assay with the aim to (i) identify and (ii) distinguish abnormalities of TP53 versus ATM and (iii) enable the identification of additional defects in the ATM-p53 pathway. Reversed transcriptase multiplex ligation-dependent probe amplification (RT-MLPA) was used to measure ATM and/or p53-dependent genes at the RNA level following DNA damage using irradiation. Here, we showed that this assay is able to identify and distinguish three subgroups of CLL tumors (i.e., TP53-defective, ATM-defective and WT) and is also able to detect additional samples with a defective DDR, without molecular aberrations in TP53 and/or ATM. These findings make the ATM-p53 RT-MLPA functional assay a promising prognostic tool for predicting treatment responses in CLL.

Emerging immunological drugs for chronic lymphocytic leukemia

INTRODUCTION

Over the last few years, several new immunological drugs, particularly monoclonal antibodies (mAbs), immunomodulatory drugs and B-cell receptor (BCR) pathway inhibitors have been developed and investigated in chronic lymphocytic leukemia (CLL). This article summarizes recent discoveries regarding their mechanism of action, pharmacological properties, clinical activity and toxicity, as well as the emerging role of these agents in CLL.

AREAS COVERED

A literature review of mAbs, BCR pathway inhibitors and immunomodulating drugs was conducted of the MEDLINE database via PubMed for articles in English. Publications from 2000 through February 2015 were scrutinized. The search terms used were alemtuzumab, BI 836826, duvelisib ibrutinib, idelalisib, lenalidomide, monoclonal antibodies, MEDI-551, MOR208, obinutuzumab, ocaratuzumab, ofatumumab, ONO-4059, otlertuzumab, spebrutinib, veltuzumab and XmAb5574 in conjunction with CLL. Conference proceedings from the previous 5 years of the American Society of Hematology, European Hematology Association, American Society of Clinical Oncology, and ACR/ARHP Annual Scientific Meetings were searched manually. Additional relevant publications were obtained by reviewing the references from the chosen articles.

EXPERT OPINION

The use of mAbs, BCR inhibitors and immunomodulating drugs is a promising new strategy for chemotherapy-free treatment of CLL. However, definitive data from ongoing and future clinical trials will aid in better defining the status of immunological drugs in the treatment of this disease.

Inflammation and pyroptosis mediate muscle expansion in an interleukin-1β (IL-1β)-dependent manner

Muscle inflammation is often associated with its expansion. Bladder smooth muscle inflammation-induced cell death is accompanied by hyperplasia and hypertrophy as the primary cause for poor bladder function. In mice, DNA damage initiated by chemotherapeutic drug cyclophosphamide activated caspase 1 through the formation of the NLRP3 complex resulting in detrusor hyperplasia. A cyclophosphamide metabolite, acrolein, caused global DNA methylation and accumulation of DNA damage in a mouse model of bladder inflammation and in cultured bladder muscle cells. In correlation, global DNA methylation and NLRP3 expression was up-regulated in human chronic bladder inflammatory tissues. The epigenetic silencing of DNA damage repair gene, Ogg1, could be reversed by the use of demethylating agents. In mice, demethylating agents reversed cyclophosphamide-induced bladder inflammation and detrusor expansion. The transgenic knock-out of Ogg1 in as few as 10% of the detrusor cells tripled the proliferation of the remaining wild type counterparts in an in vitro co-culture titration experiment. Antagonizing IL-1β with Anakinra, a rheumatoid arthritis therapeutic, prevented detrusor proliferation in conditioned media experiments as well as in a mouse model of bladder inflammation. Radiation treatment validated the role of DNA damage in the NLRP3-associated caspase 1-mediated IL-1β secretory phenotype. A protein array analysis identified IGF1 to be downstream of IL-1β signaling. IL-1β-induced detrusor proliferation and hypertrophy could be reversed with the use of Anakinra as well as an IGF1 neutralizing antibody. IL-1β antagonists in current clinical practice can exploit the revealed mechanism for DNA damage-mediated muscular expansion.

A new hope: novel therapeutic approaches to treatment of chronic lymphocytic leukaemia with defects in TP53

Chronic lymphocytic leukaemia (CLL) is an indolent B-cell malignancy with heterogeneous outcomes. Chromosomal abnormalities in CLL are predictive of the natural disease course; del(11q) and del(17p) are recognized as high risk genetic lesions. Del(17p) is associated with an impaired function of TP53, a key tumour suppressor, and is particularly problematic. Such patients respond poorly to chemo-immunotherapy and have significantly shorter survival compared to patients with standard and low-risk cytogenetics. While TP53 pathway defects are rare at initial diagnosis, their frequency increases in relapsed CLL. Until very recently, this group of patients represented an unmet clinical need with few therapeutic options. However, the advent of targeted therapies has expanded the drug armamentarium and introduced new hope for these highly refractory patients. Agents that target B-cell receptor signalling, BH3-mimetics and others induce apoptosis of the neoplastic B-cells in a TP53-independent manner. Their use in the clinic is associated with remarkable activity in patients with del(17p). In this review we discuss the frequency and clinical significance of del(17p) and genetic mutations leading to disrupted TP53, the putative role of other TP53 homologues, and the results of key clinical trials involving both conventional chemotherapy and novel agents.