Update on therapy of chronic lymphocytic leukemia

Treatment of Chronic Lymphocytic Leukemia in the Personalized Medicine Era

Chronic lymphocytic leukemia is a lymphoproliferative disorder marked by the expansion of monoclonal, mature CD5+CD23+ B cells in peripheral blood, secondary lymphoid tissues, and bone marrow. The disease exhibits significant heterogeneity, with numerous somatic genetic alterations identified in the neoplastic clone, notably mutated TP53 and immunoglobulin heavy chain mutational statuses. Recent studies emphasize the pivotal roles of genetics and patient fragility in treatment decisions. This complexity underscores the need for a personalized approach, tailoring interventions to individual genetic profiles for heightened efficacy. The era of personalized treatment in CLL signifies a transformative shift, holding the potential for improved outcomes in the conquest of this intricate hematologic disorder. This review plays a role in elucidating the evolving CLL treatment landscape, encompassing all reported genetic factors. Through a comprehensive historical analysis, it provides insights into the evolution of CLL management. Beyond its retrospective nature, this review could be a valuable resource for clinicians, researchers, and stakeholders, offering a window into the latest advancements. In essence, it serves as a dynamic exploration of our current position and the promising prospects on the horizon.

NOD2 silencing promotes cell apoptosis and inhibits drug resistance in chronic lymphocytic leukemia by inhibiting the NF-κB signaling pathway

Recent years have witnessed increasing studies on the effect of epigenetic silencing of genes in the progression of chronic lymphocytic leukemia (CLL). This study investigates whether the nucleotide binding oligomerization domain containing 2 (NOD2) participates in the cell apoptosis and drug resistance of CLL cells. Cells were treated with adriamycin (ADR), etoposide, aclacinomycin and daunorubicin. After treatment, drug resistance and cell proliferation were examined to detect the inhibitory effect of ADR on cell proliferation; flow cytometry to identify ADR accumulation, the cell cycle distribution and apoptosis after transfection, and rhodamine 123 accumulation and efflux tests to assess P-glycoprotein (P-gp) function. NOD2 silencing or inhibition of the nuclear factor kappa-B (NF-κB) signaling pathway suppressed the multidrug resistance level in CLL, the inhibition rate, and cell proliferation caused by ADR at concentrations of approximately 0.25-1.5 μmol/L. Greater accumulation of ADR was observed in the CLL-AAT cell line than in the CLL-AAT/A02 cell line, but NOD2 silencing or inhibition of the NF-κB signaling pathway further increased the accumulation of ADR drugs in the CLL-AAT cell line and inhibited the drug efflux pump function of P-gp. Additionally, NOD2 silencing or NF-κB signaling pathway inhibition increased the apoptotic rate. The results of this study indicate that NOD2 promotes cell apoptosis and reduces the drug resistance of CLL by inhibiting the NF-κB signaling pathway.

Mucosal-associated invariant T cells for cancer immunotherapy

Human mucosal-associated invariant T (MAIT) cells are characterized by their expression of an invariant TCR α chain Vα7.2-Jα33/Jα20/Jα12 paired with a restricted TCR β chain. MAIT cells recognize microbial peptides presented by the highly conserved MHC class I-like molecule MR1 and bridge the innate and acquired immune systems to mediate augmented immune responses. Upon activation, MAIT cells rapidly proliferate, produce a variety of cytokines and cytotoxic molecules, and trigger efficient antitumor immunity. Administration of a representative MAIT cell ligand 5-OP-RU effectively activates MAIT cells and enhances their antitumor capacity. In this review, we introduce MAIT cell biology and their importance in antitumor immunity, summarize the current development of peripheral blood mononuclear cell-derived and stem cell-derived MAIT cell products for cancer treatment, and discuss the potential of genetic engineering of MAIT cells for off-the-shelf cancer immunotherapy.

Off-the-shelf third-party HSC-engineered iNKT cells for ameliorating GvHD while preserving GvL effect in the treatment of blood cancers

Allo-HSCT is a curative therapy for hematologic malignancies owing to GvL effect mediated by alloreactive T cells; however, the same T cells also mediate GvHD, a severe side effect limiting the widespread application of allo-HSCT in clinics. Invariant natural killer T (iNKT) cells can ameliorate GvHD while preserving GvL effect, but the clinical application of these cells is restricted by their scarcity. Here, we report the successful generation of third-party HSC-engineered human iNKT (3rdHSC-iNKT) cells using a method combining HSC gene engineering and in vitro HSC differentiation. The 3rdHSC-iNKT cells closely resembled the CD4-CD8-/+ subsets of endogenous human iNKT cells in phenotype and functionality. These cells displayed potent anti-GvHD functions by eliminating antigen-presenting myeloid cells in vitro and in xenograft models without negatively impacting tumor eradication by allogeneic T cells in preclinical models of lymphoma and leukemia, supporting 3rdHSC-iNKT cells as a promising off-the-shelf cell therapy candidate for GvHD prophylaxis.

Sequential Single-Cell Transcriptional and Protein Marker Profiling Reveals TIGIT as a Marker of CD19 CAR-T Cell Dysfunction in Patients with Non-Hodgkin Lymphoma

Chimeric antigen receptor T-cell (CAR-T cell) therapy directed at CD19 produces durable remissions in the treatment of relapsed/refractory non-Hodgkin lymphoma (NHL). Nonetheless, many patients receiving CD19 CAR-T cells fail to respond for unknown reasons. To reveal changes in 4-1BB-based CD19 CAR-T cells and identify biomarkers of response, we used single-cell RNA sequencing and protein surface marker profiling of patient CAR-T cells pre- and postinfusion into patients with NHL. At the transcriptional and protein levels, we note the evolution of CAR-T cells toward a nonproliferative, highly differentiated, and exhausted state, with an enriched exhaustion profile in CAR-T cells of patients with poor response marked by TIGIT expression. Utilizing in vitro and in vivo studies, we demonstrate that TIGIT blockade alone improves the antitumor function of CAR-T cells. Altogether, we provide evidence of CAR-T cell dysfunction marked by TIGIT expression driving a poor response in patients with NHL.

SIGNIFICANCE

This is the first study investigating the mechanisms linked to CAR-T patient responses based on the sequential analysis of manufactured and infused CAR-T cells using single-cell RNA and protein expression data. Furthermore, our findings are the first to demonstrate an improvement of CAR-T cell efficacy with TIGIT inhibition alone. This article is highlighted in the In This Issue feature, p. 1825.

Evaluation of the Pharmacokinetics and Safety of a Single Dose of Acalabrutinib in Subjects With Hepatic Impairment

Acalabrutinib received approval for treatment of adult patients with mantle cell lymphoma who received at least one prior therapy and adult patients with chronic lymphocytic leukemia or small lymphocytic lymphoma. This study investigated the impact of hepatic impairment (HI) on acalabrutinib PK and safety at a single 50-mg dose in fasted subjects. This study was divided into two studies: study 1, an open-label, parallel-group study in Child-Pugh Class A or B subjects and healthy subjects, and study 2, an open-label, parallel-group study in Child-Pugh Class C subjects and healthy subjects. Baseline characteristics and safety profiles were similar across groups. Acalabrutinib exposure (area under the curve [AUC]) increased slightly (1.90- and 1.48-fold) in subjects with mild (Child-Pugh Class A) and moderate (Child-Pugh Class B) HI compared with healthy subjects. In severe HI (Child-Pugh Class C), acalabrutinib exposure (AUC and maximum concentration [C_max ]) increased approximately 5.0-fold and 3.6-fold, respectively. Results were consistent across total and unbound exposures. Severe HI did not impact total/unbound metabolite (ACP-5862) exposures; metabolite to parent ratio decreased to 0.6 - 0.8 (versus 3.1 - 3.6 in healthy subjects). In summary, single oral dose of 50 mg acalabrutinib was safe and well tolerated in subjects with mild, moderate and severe HI and in healthy control subjects. In subjects with severe HI, mean acalabrutinib exposure increased by up to 5-fold and should be avoided. Acalabrutinib does not require dose adjustment in patients with mild or moderate HI. This article is protected by copyright. All rights reserved.

Upgrade of an old drug: Auranofin in innovative cancer therapies to overcome drug resistance and to increase drug effectiveness

Auranofin is an oral gold(I) compound, initially developed for the treatment of rheumatoid arthritis. Currently, Auranofin is under investigation for oncological application within a drug repurposing plan due to the relevant antineoplastic activity observed both in vitro and in vivo tumor models. In this review, we analysed studies in which Auranofin was used as a single drug or in combination with other molecules to enhance their anticancer activity or to overcome chemoresistance. The analysis of different targets/pathways affected by this drug in different cancer types has allowed us to highlight several interesting targets and effects of Auranofin besides the already well-known inhibition of thioredoxin reductase. Among these targets, inhibitory-κB kinase, deubiquitinates, protein kinase C iota have been frequently suggested. To rationalize the effects of Auranofin by a system biology-like approach, we exploited transcriptomic data obtained from a wide range of cell models, extrapolating the data deposited in the Connectivity Maps website and we attempted to provide a general conclusion and discussed the major points that need further investigation.

Gold Cluster Capped with a BCL-2 Antagonistic Peptide Exerts Synergistic Antitumor Activity in Chronic Lymphocytic Leukemia Cells

Chronic lymphocytic leukemia (CLL) is still incurable by conventional chemotherapy due to the resistance to apoptosis. We have previously found that a peptide-capped gold cluster (Au₂₅Sv₉) can target on the aberrant oxidative stress in CLL cells to specially inhibit thioredoxin reductase (TrxR) activity, resulting in significant apoptosis. However, the required doses of the gold cluster for inducing apoptosis are high, restricting its potential for further applications. Notably, the most recent studies suggested that CLL cells overexpressed antiapoptotic BCL-2 protein to prevent chemotherapy-induced apoptosis, indicating that BCL-2 could be a promising target for CLL therapy. Regrettably, the nonmitochondrial-targeted Au₂₅Sv₉ has little effect on BCL-2. In this study, we successfully screened a modified BADBH3 peptide (B1P) that could antagonize BCL-2 protein in CLL cells. We found that B1P could effectively sensitize MEC-1 cells to a subliminal dose of Au₂₅Sv₉. To simplify the treatment regimen, we directly fabricated a gold cluster capped with the B1P peptides by one-step synthesis to integrate the BCL-2 antagonistic activity into the gold the cluster, named BGC. We already found that low doses of BGC could significantly induce more apoptosis in MEC-1 cells than equivalent doses of the Au₂₅Sv₉ cluster or B1P peptide alone. Mechanistically, in addition to the inherent inhibitory effect of gold clusters on TrxR activity, BGC could bind to BCL-2 on mitochondria and activate the BCL-2 family-mediated mitochondrial apoptosis cascade more effectively. These results demonstrated that antagonizing the overexpressed BCL-2 in CLL cells, together with inhibiting TrxR simultaneously by a single gold cluster, is a promising strategy for the treatment of CLL cells. This study will provide a paradigm and reference for the development of functionalized gold clusters with rationally designed peptides, and opens up a new opportunity for the treatment of CLL in clinical settings.

MicroRNA-425 inhibits proliferation of chronic lymphocytic leukaemia cells through regulation of the Bruton's tyrosine kinase/phospholipase Cγ2 signalling pathway

The present study aimed to investigate the effects of microRNA (miR)-425 on the proliferation of chronic lymphocytic leukaemia (CLL) cells and the possible underlying mechanisms. The expression of miR-425 was determined in the B lymphocytes of CLL patients and in normal B lymphocytes by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). In addition, MEC-1 cells transfected with miR-425 negative control (NC) or miR-425 mimic were examined. The cell proliferation of different groups was evaluated using an MTT assay, and cell cycle distribution was evaluated using flow cytometry analysis. A dual-luciferase reporter assay was used to verify whether Bruton's tyrosine kinase (BTK) was a target of miR-425. Furthermore, the expression levels of BTK, phospholipase Cγ2 (PLCγ2), Ki-67 and proliferating cell nuclear antigen (PCNA) were determined by RT-qPCR and western blotting. The results revealed that the expression of miR-425 was significantly downregulated in B lymphocytes obtained from CLL patients as compared with that in normal B lymphocytes. When cells were transfected with miR-425 mimic, the proliferation of MEC-1 cells was significantly inhibited at 24, 48 and 72 h compared with the proliferation of control cells. Additionally, the ratio of G0/G1 cells was significantly increased and the ratio of G2/M cells was significantly decreased in miR-425-overexpressing cells compared with that in control cells. The luciferase reporter assay revealed that miR-425 binds to the 3'-untranslated region of BTK mRNA. Finally, BTK, PLCγ2, Ki-67 and PCNA expression was significantly inhibited at the mRNA and protein level in cells where miR-425 was upregulated. In conclusion, miR-425 inhibits the proliferation of MEC-1 cells, potentially by inhibiting BTK/PLCγ2 signalling, and Ki-67 and PCNA expression levels. These results provide a deeper insight for understanding the development of CLL and suggest a potential novel target for the treatment of CLL patients.

A laboratory-based scoring system predicts early treatment in Rai 0 chronic lymphocytic leukemia

We present a laboratory-based prognostic calculator (designated CRO score) to risk stratify treatment-free survival in early stage (Rai 0) chronic lymphocytic leukemia (CLL) developed using a training-validation model in a series of 1,879 cases from Italy, the United Kingdom and the United States. By means of regression analysis, we identified five prognostic variables with weighting as follows: deletion of the short arm of chromosome 17 and unmutated immunoglobulin heavy chain gene status, 2 points; deletion of the long arm of chromosome 11, trisomy of chromosome 12, and white blood cell count >32.0x103/microliter, 1 point. Low-, intermediate- and high-risk categories were established by recursive partitioning in a training cohort of 478 cases, and then validated in four independent cohorts of 144 / 395 / 540 / 322 cases, as well as in the composite validation cohort. Concordance indices were 0.75 in the training cohort and ranged from 0.63 to 0.74 in the four validation cohorts (0.69 in the composite validation cohort). These findings advocate potential application of our novel prognostic calculator to better stratify early-stage CLL, and aid case selection in risk-adapted treatment for early disease. Furthermore, they support immunocytogenetic analysis in Rai 0 CLL being performed at the time of diagnosis to aid prognosis and treatment, particularly in today's chemofree era.

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.

Clinicohematological parameters and outcomes in a cohort of chronic lymphocytic leukemia patients with Deletion 17p from Pakistan

Background

Chronic lymphocytic leukemia (CLL) exhibits profound heterogeneity in its clinical course. Its clinicohematological and cytogenetic features play a significant role in determining the clinical course and in predicting the treatment response and prognosis. In this context, 17p deletion is known to predict a poor prognosis, as these cases are refractory to conventional therapy. This study aimed to evaluate the clinicohematological characteristics, outcomes, and prognostic factors among CLL patients with and without del 17p in Pakistan.

Methods

This prospective observational study was conducted at the Department of Haematology, Armed Forces Institute of Pathology (Rawalpindi, Pakistan) between January 2013 and December 2017. Patients were diagnosed based on the International Workshop on Chronic Lymphocytic Leukaemia IWCLL criteria, their clinicohematological parameters were recorded, and cytogenetic analyses were performed. The time from diagnosis to treatment and the 2-year overall survival rate were also evaluated.

Results

We evaluated 130 CLL cases, including 24 patients (18.5%) with del 17p, who included 18 men (75%) and 6 women (25%). The median age was 68 years. Binet stage C was detected at the presentation in 16 patients (67%). Treatment was administered to 14 patients (70%) at a median interval of 11 months (range, 0-28 mo) after diagnosis. The overall response rate was 64.3%, the median event-free survival was 9 months (range, 1-23 mo), and the 2-year overall survival rate was 65%.

Conclusion

Del 17p is relatively common in Pakistan, and patients harboring this deletion had poor treatment response and survival outcomes.

Selecting Frontline Therapy for CLL in 2018

The treatment landscape of chronic lymphocytic leukemia (CLL) has changed dramatically in the last few years. The role of chemoimmunotherapy has declined significantly for patients with CLL. Fludarabine, cyclophosphamide, rituximab chemotherapy remains the standard frontline therapy for young fit patients with CLL, especially if IGHV mutated. For older adults, ibrutinib has been shown to be superior to chlorambucil. Hence, the role of chlorambucil monotherapy in the current era in the management of CLL is limited. The combination of chlorambucil and obinutuzumab is an alternative option for patients with comorbidities. For patients with del(17p), ibrutinib has become the standard treatment in the frontline setting. Several phase 3 trials with novel targeted agents, either as monotherapy or in combination, are either ongoing or have completed accrual. The results of many of these trials are expected in the next 1 to 2 years, and they will further help refine the frontline treatment strategy.

The phase 3 DUO trial: duvelisib vs ofatumumab in relapsed and refractory CLL/SLL

Duvelisib (also known as IPI-145) is an oral, dual inhibitor of phosphatidylinositol 3-kinase δ and γ (PI3K-δ,γ) being developed for treatment of hematologic malignancies. PI3K-δ,γ signaling can promote B-cell proliferation and survival in clonal B-cell malignancies, such as chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). In a phase 1 study, duvelisib showed clinically meaningful activity and acceptable safety in CLL/SLL patients. We report here the results of DUO, a global phase 3 randomized study of duvelisib vs ofatumumab monotherapy for patients with relapsed or refractory (RR) CLL/SLL. Patients were randomized 1:1 to oral duvelisib 25 mg twice daily (n = 160) or ofatumumab IV (n = 159). The study met the primary study end point by significantly improving progression-free survival per independent review committee assessment compared with ofatumumab for all patients (median, 13.3 months vs 9.9 months; hazard ratio [HR] = 0.52; P < .0001), including those with high-risk chromosome 17p13.1 deletions [del(17p)] and/or TP53 mutations (HR = 0.40; P = .0002). The overall response rate was significantly higher with duvelisib (74% vs 45%; P < .0001) regardless of del(17p) status. The most common adverse events were diarrhea, neutropenia, pyrexia, nausea, anemia, and cough on the duvelisib arm, and neutropenia and infusion reactions on the ofatumumab arm. The DUO trial data support duvelisib as a potentially effective treatment option for patients with RR CLL/SLL. This trial was registered at www.clinicaltrials.gov as #NCT02004522.

Au nanoclusters suppress chronic lymphocytic leukaemia cells by inhibiting thioredoxin reductase 1 to induce intracellular oxidative stress and apoptosis

Chronic lymphocytic leukaemia (CLL) is a rare blood cancer that always relapses as refractory disease and eventually leads to death. To date, therapeutic options for CLL patients are scarce and there is an urgent need to develop novel chemotherapeutics that are both effective and safe. Gold-containing compounds induce a lethal oxidative and endoplasmic reticulum stress response in cultured and primary CLL cells via inhibition of thioredoxin reductase (TrxR). However, traditional gold-containing medicines have revealed side effects during clinical applications. Therefore, safer gold-containing drugs are needed to overcome this challenge. In this study, a novel peptide templated gold cluster Au₂₅Sv₉ was synthesized and its therapeutic effect on CLL cells was evaluated. This nanocluster could induce cell apoptosis in MEC-1 cells in a dose-dependent manner which correlated with the uptake amount of clusters in cells. As expected, increasing intracellular reactive oxidative species (ROS) in MEC-1 cells was exhibited with the increase of cluster dosage. Further analyses demonstrated the underlying mechanism that the nanoclusters suppress the activity of TrxR1, increase the level of intracellular ROS, destroy the mitochondrial membrane potential and finally trigger the mitochondrial apoptotic pathway in MEC-1 cells. Furthermore, the direct interaction between Au₂₅Sv₉ clusters and TrxR1 was confirmed for the first time by isothermal titration calorimetry. These findings explored the preclinical efficacy and potential mechanism of gold clusters in CLL therapy and provided a fundamental reference for the development of other novel gold-containing chemotherapeutics to treat CLL.

Economic Burden of Chronic Lymphocytic Leukemia in the Era of Oral Targeted Therapies in the United States

Purpose Oral targeted therapies represent a significant advance for the treatment of patients with chronic lymphocytic leukemia (CLL); however, their high cost has raised concerns about affordability and the economic impact on society. Our objective was to project the future prevalence and cost burden of CLL in the era of oral targeted therapies in the United States. Methods We developed a simulation model that evaluated the evolving management of CLL from 2011 to 2025: chemoimmunotherapy (CIT) as the standard of care before 2014, oral targeted therapies for patients with del(17p) and relapsed CLL from 2014, and for first-line treatment from 2016 onward. A comparator scenario also was simulated where CIT remained the standard of care throughout. Disease progression and survival parameters for each therapy were based on published clinical trials. Results The number of people living with CLL in the United States is projected to increase from 128,000 in 2011 to 199,000 by 2025 (55% increase) due to improved survival; meanwhile, the annual cost of CLL management will increase from $0.74 billion to $5.13 billion (590% increase). The per-patient lifetime cost of CLL treatment will increase from $147,000 to $604,000 (310% increase) as oral targeted therapies become the first-line treatment. For patients enrolled in Medicare, the corresponding total out-of-pocket cost will increase from $9,200 to $57,000 (520% increase). Compared with the CIT scenario, oral targeted therapies resulted in an incremental cost-effectiveness ratio of $189,000 per quality-adjusted life-year. Conclusion The increased benefit and cost of oral targeted therapies is projected to enhance CLL survivorship but can impose a substantial financial burden on both patients and payers. More sustainable pricing strategies for targeted therapies are needed to avoid financial toxicity to patients.

CD69 expression potentially predicts response to bendamustine and its modulation by ibrutinib or idelalisib enhances cytotoxic effect in chronic lymphocytic leukemia

Clinical responses to bendamustine in chronic lymphocytic leukemia (CLL) are highly heterogeneous and no specific markers to predict sensitivity to this drug have been reported. In order to identify biomarkers of response, we analyzed the in vitro activity of bendamustine and the gene expression profile in primary CLL cells. We observed that mRNA expression of CD69 (CD69) and ITGAM (CD11b) constitute the most powerful predictor of response to bendamustine. When we interrogated the predictive value of the corresponding cell surface proteins, the expression of the activation marker CD69 was the most reliable predictor of sensitivity to bendamustine. Importantly, a multivariate analysis revealed that the predictive value of CD69 expression was independent from other clinico-biological CLL features. We also showed that when CLL cells were co-cultured with distinct subtypes of stromal cells, an upregulation of CD69 was accompanied by a reduced sensitivity to bendamustine. In agreement with this, tumor cells derived from lymphoid tumor niches harbored higher CD69 expression and were less sensitive to bendamustine than their peripheral blood counterparts. Furthermore, pretreatment of CD69 ^high CLL cases with the B-cell receptor (BCR) pathway inhibitors ibrutinib and idelalisib decreased CD69 levels and enhanced bendamustine cytotoxic effect. Collectively, our findings indicate that CD69 could be a predictor of bendamustine response in CLL patients and the combination of clinically-tested BCR signaling inhibitors with bendamustine may represent a promising strategy for bendamustine low responsive CLL cases.

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.

A Patient with Abnormal Kidney Function and a Monoclonal Light Chain in the Urine

Monoclonal gammopathy is increasingly recognized as a cause of kidney injury. These renal conditions behave differently than ones without monoclonal gammopathy and require specific treatment. To avoid misdiagnosis, testing for paraprotein should be performed in addition to vasculitis and autoimmune diseases serologies in adults with unexplained AKI or proteinuria. Because the prevalence of monoclonal gammopathy is much more common than glomerular diseases, the nephrotoxicity of the monoclonal protein must be confirmed before cytotoxic therapy is initiated. This can only be done by a kidney biopsy. After a monoclonal gammopathy of renal significant is verified, the evaluation should then focus on the identification of the pathologic clone, because therapy is clone specific. We present this patient to illustrate the clinical presentation of a patient with renal dysfunction and a monoclonal gammopathy. This patient is also used to discuss the diagnostic process in detail when monoclonal gammopathy-associated renal disease is suspected.

The CLL12 trial protocol: a placebo-controlled double-blind Phase III study of ibrutinib in the treatment of early-stage chronic lymphocytic leukemia patients with risk of early disease progression

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.

CD126 and Targeted Therapy with Tocilizumab in Chronic Lymphocytic Leukemia

PURPOSE

IL6 promotes tumor growth and signal transduction via both its membrane-bound (CD126) and soluble receptors (sCD126). We aimed to study whether the levels of CD126 expression in chronic lymphocytic leukemic (CLL) cells can predict in vitro and in vivo treatment response.

EXPERIMENTAL DESIGN

The levels of membrane-bound CD126 expression were determined on freshly isolated CLL B cells (n = 58) using flow cytometry. These CLL cells were treated with chlorambucil or fludarabine with or without anti-CD126 antibody tocilizumab for 24 hours and IL6-mediated STAT3 transcriptional activity and cell-cycle alteration were evaluated.

RESULTS

CD126 surface expression was found in all cases and positively correlated with the levels of in vivo constitutive STAT3 activity. The levels of CD126 expression were significantly and positively correlated with the resistance of CLL cells to in vitro treatment with chlorambucil or fludarabine and poor in vivo treatment response of CLL patients. Blocking IL6 signaling with the anti-CD126 antibody, tocilizumab, had profound effects on STAT3-mediated survival and growth signals: decreased Mcl-1 and Bcl-xL, favoring an apoptotic profile; and decreased p27 with increased cyclin E and CDK2 expression, leading to cell-cycle shift from G0-G1 These tocilizumab-mediated changes induced chemosensitization in resistant CLL cells, with the greatest effect seen in cells with higher CD126 expression (P < 0.001).

CONCLUSIONS

CLL cells with higher CD126 expression are more resistant to treatment in vivo and in vitro via IL6-CD126-STAT3 axis. Blocking CD126 using tocilizumab sensitizes CLL cells to chemotherapy. Clin Cancer Res; 22(10); 2462-9. ©2015 AACR.

The HELIOS trial protocol: a phase III study of ibrutinib in combination with bendamustine and rituximab in relapsed/refractory chronic lymphocytic leukemia

Ibrutinib is an orally administered, covalent inhibitor of Bruton's tyrosine kinase with activity in B-cell malignancies based on Phase I/II studies. We describe the design and rationale for the Phase III HELIOS trial (trial registration: EudraCT No. 2012-000600-15; UTN No. U1111-1135-3745) investigating whether ibrutinib added to bendamustine and rituximab (BR) provides benefits over BR alone in patients with relapsed/refractory chronic lymphocytic leukemia/small lymphocytic lymphoma. Eligible patients must have relapsed/refractory disease measurable on CT scan and meet ≥ 1 International Workshop on Chronic Lymphocytic Leukemia criterion for requiring treatment; patients with del(17p) are excluded. All patients receive BR (maximum six cycles) as background therapy and are randomized 1:1 to placebo or ibrutinib 420 mg/day. Treatment with ibrutinib or placebo will start concomitantly with BR and continue until disease progression or unacceptable toxicity. The primary end point is progression-free survival. Secondary end points include safety, objective response rate, overall survival, rate of minimal residual disease-negative remissions, and patient-reported outcomes. Tumor response will be assessed using the International Workshop on Chronic Lymphocytic Leukemia guidelines.

A critical appraisal of ibrutinib in the treatment of mantle cell lymphoma and chronic lymphocytic leukemia

Although chemo-immunotherapy remains at the forefront of first-line treatment for mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL), small molecules, such as ibrutinib, are beginning to play a significant role, particularly in patients with multiply relapsed or chemotherapy-refractory disease and where toxicity is an overriding concern. Ibrutinib is a first-in-class, oral inhibitor of Bruton's tyrosine kinase, which functions by irreversible inhibition of the downstream signaling pathway of the B-cell receptor, which normally promotes cell survival and proliferation. Early clinical trials have demonstrated excellent tolerability and a modest side-effect profile even in elderly and multiply pretreated patient cohorts. Although the majority of disease responses tend to be partial, efficacy data have also been encouraging with more than two-thirds of patients with CLL and MCL demonstrating a durable response, even in the high-risk disease setting. Resistance mechanisms are only partially understood and appear to be multifactorial, including the binding site mutation C481S, and escape through other common cell-signaling pathways. This article appraises the currently available data on safety and efficacy from clinical trials of ibrutinib in the management of MCL and CLL, both as a single agent and in combination with other therapies, and considers how this drug is likely to be used in future clinical practice.

Initial treatment of CLL: integrating biology and functional status

A better understanding of the biology of chronic lymphocytic leukemia (CLL) has led to significant advances in therapeutic strategies for patients with CLL. Chemoimmunotherapy (CIT) has been the standard first-line therapy for CLL. Age and comorbidities can help decide which patients may benefit from a CIT approach. FCR (fludarabine, cyclophosphamide, and rituximab) is the current standard treatment option for younger patients with CLL. For older patients and for patients with renal dysfunction, bendamustine and rituximab may be a better option. For older patients with comorbidities who may not be able to tolerate intensive CIT, the combination treatment of chlorambucil and obinutuzumab or ofatumumab is an option. For patients with del(17p), ibrutinib is the treatment of choice. Several ongoing phase 3 clinical trials with novel therapies will further refine the frontline therapy of CLL.

Trial Watch: Proteasomal inhibitors for anticancer therapy

The so-called "ubiquitin-proteasome system" (UPS) is a multicomponent molecular apparatus that catalyzes the covalent attachment of several copies of the small protein ubiquitin to other proteins that are generally (but not always) destined to proteasomal degradation. This enzymatic cascade is crucial for the maintenance of intracellular protein homeostasis (both in physiological conditions and in the course of adaptive stress responses), and regulates a wide array of signaling pathways. In line with this notion, defects in the UPS have been associated with aging as well as with several pathological conditions including cardiac, neurodegenerative, and neoplastic disorders. As transformed cells often experience a constant state of stress (as a result of the hyperactivation of oncogenic signaling pathways and/or adverse microenvironmental conditions), their survival and proliferation are highly dependent on the integrity of the UPS. This rationale has driven an intense wave of preclinical and clinical investigation culminating in 2003 with the approval of the proteasomal inhibitor bortezomib by the US Food and Drug Administration for use in multiple myeloma patients. Another proteasomal inhibitor, carfilzomib, is now licensed by international regulatory agencies for use in multiple myeloma patients, and the approved indications for bortezomib have been extended to mantle cell lymphoma. This said, the clinical activity of bortezomib and carfilzomib is often limited by off-target effects, innate/acquired resistance, and the absence of validated predictive biomarkers. Moreover, the antineoplastic activity of proteasome inhibitors against solid tumors is poor. In this Trial Watch we discuss the contribution of the UPS to oncogenesis and tumor progression and summarize the design and/or results of recent clinical studies evaluating the therapeutic profile of proteasome inhibitors in cancer patients.

The casein kinase 2 inhibitor, CX-4945, as an anti-cancer drug in treatment of human hematological malignancies

The casein kinase 2 (CK2) protein kinase is a pro-survival kinase and therapeutic target in treatment of various human cancers. CK2 overexpression has been demonstrated in hematological malignancies, including chronic lymphocytic leukemia, chronic myeloid leukemia, acute lymphoblastic leukemia, acute myeloid leukemia, and multiple myeloma. CX-4945, also known as Silmitasertib, is an orally administered, highly specific, ATP-competitive inhibitor of CK2. CX-4945 induces cytotoxicity and apoptosis and is currently being evaluated in clinical trials for treatment of many cancer types. In the past 2 years, the focus on the therapeutic potential of CX-4945 has shifted from solid tumors to hematological malignancies. CX-4945 exerts anti-proliferative effects in hematological tumors by downregulating CK2 expression and suppressing activation of CK2-mediated PI3K/Akt/mTOR signaling pathways. Furthermore, combination of CX-4945 with other inhibitors yielded synergistic effects in cell death induction. These new findings demonstrate that CK2 overexpression contributes to blood cancer cell survival and resistance to chemotherapy. Combinatorial use of CX-4945 is a promising therapeutic tool for treatment of hematological malignancies.

The Bruton tyrosine kinase inhibitor ibrutinib with chemoimmunotherapy in patients with chronic lymphocytic leukemia

The safety and efficacy of ibrutinib, an oral inhibitor of Bruton tyrosine kinase, were evaluated with chemoimmunotherapy (CIT) in a multicenter phase 1b study. Patients with relapsed/refractory chronic lymphocytic leukemia received bendamustine and rituximab (BR) or fludarabine, cyclophosphamide, and rituximab (FCR) for up to 6 cycles with daily ibrutinib (420 mg) until progressive disease or unacceptable toxicity. Enrollment to FCR-ibrutinib closed early due to a lack of fludarabine-naïve previously treated patients. No patients treated with BR-ibrutinib (n = 30) or FCR-ibrutinib (n = 3) experienced prolonged hematologic toxicity in cycle 1 (primary end point). Tolerability was as expected with either CIT or single-agent ibrutinib. The overall response rate (ORR) with BR-ibrutinib was 93.3%, including 16.7% complete responses (CRs) initially, which increased to 40% with the extension period. Including 1 patient with partial response with lymphocytosis, the best ORR was 96.7%. Sixteen of 21 patients with baseline cytopenias had sustained hematologic improvement. At 12 and 36 months, 86.3% and 70.3% remained progression-free, respectively. All 3 patients treated with ibrutinib-FCR achieved CR. Ibrutinib may enhance CIT efficacy without additive toxicities, providing the rationale for studying this combination in an ongoing phase 3 trial. The study is registered to www.clinicaltrials.gov as #NCT01292135.

Allogeneic stem cell transplant in patients with chronic lymphocytic leukemia with 17p deletion: consult-transplant versus consult- no-transplant analysis

Allogeneic stem cell transplant (alloSCT) can overcome the adverse prognosis of chronic lymphocytic leukemia with 17p deletion (17p- CLL). However, its applicability remains unclear. Since 2007, our leukemia service has referred patients with 17p- CLL for alloSCT at presentation. In this study, the outcomes of these patients were reviewed retrospectively to determine whether they underwent alloSCT and why patients did not undergo alloSCT. Fifty-two patients with 17p- CLL who were referred to the transplant service from 2007 to 2010 were identified. Of these patients, 32 (62%) did not undergo alloSCT, mainly because of treatment- or disease-related complications (n = 15). The 2-year post-referral overall survival rates of the alloSCT and non-SCT groups were 64% and 25%, respectively (p = 0.001). These findings suggest that while alloSCT is an effective therapy in patients with 17p- CLL, pre-SCT complications may preclude a significant proportion of patients from undergoing the procedure.

The effect of food on the pharmacokinetics of oral ibrutinib in healthy participants and patients with chronic lymphocytic leukemia

Purpose

To assess ibrutinib pharmacokinetics under fasted and fed conditions, impact of food-intake timing, and the safety and tolerability.

Methods

Three studies were analyzed. Study 1 was a randomized, open-label, single-dose, four-way crossover study in 44 healthy participants. Study 2 was a randomized, repeat-dose crossover study in 16 patients with previously treated chronic lymphocytic leukemia (CLL). Ibrutinib dose was 420 mg in both studies. Study 3 was an open-label, sequential study to assess the effect of a standard breakfast on ibrutinib 560 mg in eight healthy participants.

Results

Administration of single-dose ibrutinib under fasting conditions (study 1) resulted in approximately 60 % of exposure compared with drug intake either 30 min before, 30 min after (fed), or 2 h after a high-fat meal. Similar food effect was observed (study 3) when ibrutinib was given 30 min before meal. In CLL patients (study 2), the C_max and AUC under fasting conditions were 43 and 61 %, respectively, relative to fed conditions. When administered once-daily in uncontrolled food-intake conditions (≥30 min before or 2 h after), exposures were slightly (≈30 %) lower than in fed condition. When corrected for repeated dosing, pharmacokinetic parameters in healthy participants and patients were comparable. Ibrutinib was generally well tolerated in all settings studied.

Conclusions

Ibrutinib administered in fasted condition reduces exposure to approximately 60 % as compared with dosing in proximity to food-intake, regardless of timing/type of meal. Because repeated drug intake in fasted condition is unlikely, no food restrictions may be needed to administer ibrutinib.

Electronic supplementary material

The online version of this article (doi:10.1007/s00280-015-2708-9) contains supplementary material, which is available to authorized users.

Apoptosis inducers in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is characterized by a typical defect in apoptosis and is still an incurable disease. Numerous apoptosis inducers have been described. These synthetic compounds and natural products (mainly derived from plants) display antileukemic properties in vitro and in vivo and some have even been tested in the clinic in CLL. They act through several different mechanisms. Most of them involve proteins of the Bcl-2 family, which are the key regulators in triggering the mitochondrial pathway of caspase-dependent apoptosis. Thus, the Mcl-1/Noxa axis appeared as a target. Here I overview natural and synthetic apoptosis inducers and their mechanisms of action in CLL cells. Opportunities for developing novel, apoptosis-based therapeutics are presented.

Targeting chronic lymphocytic leukemia using CIGB-300, a clinical-stage CK2-specific cell-permeable peptide inhibitor

Chronic lymphocytic leukemia (CLL) remains an incurable malignancy, urging for the identification of new molecular targets for therapeutic intervention. CLL cells rely on overexpression and hyperactivation of the ubiquitous serine/threonine protein kinase CK2 for their viability in vitro. CIGB-300 is a cell-permeable selective CK2 inhibitor peptide undergoing clinical trials for several cancers. Here, we show that CIGB-300 promotes activation of the tumor suppressor PTEN and abrogates PI3K-mediated downstream signaling in CLL cells. In accordance, CIGB-300 decreases the viability and proliferation of CLL cell lines, promotes apoptosis of primary leukemia cells and displays antitumor efficacy in a xenograft mouse model of human CLL. Our studies provide pre-clinical support for the testing and possible inclusion of CK2 inhibitors in the clinical arsenal against CLL.

Harnessing the fcμ receptor for potent and selective cytotoxic therapy of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a B-cell malignancy in need of new, effective, and safe therapies. The recently identified IgM receptor FcμR is overexpressed on malignant B cells in CLL and mediates the rapid internalization and lysosomal shuttling of IgM via its Fc fragment (Fcμ). To exploit this internalization and trafficking pathway for targeted drug delivery, we engineered an IgM-derived protein scaffold (Fcμ) and linked it with the cytotoxic agent monomethylauristatin F. This Fcμ-drug conjugate was selectively toxic for FcμR-expressing cell lines in vitro and for CLL cells but not autologous normal T cells ex vivo. Notably, the cytotoxic activity of the Fcμ-drug conjugate was maintained in CLL cells carrying a 17p deletion, which predicts resistance to standard chemotherapy. Next, we tested the possible therapeutic application of the Fcμ-drug conjugate in immunodeficient NOD/SCID/IL-2Rγ(null) (NSG) mice engrafted with peripheral blood cells from patients with leukemia. Three intravenous injections of the Fcμ-drug conjugate over a 10-day period were well tolerated and selectively killed the human CLL cells but not the coengrafted autologous human T cells. In summary, we developed a novel strategy for targeted cytotoxic therapy of CLL based on the unique properties of FcμR. FcμR-targeted drug delivery showed potent and specific therapeutic activity in CLL, thus providing proof of concept for FcμR as a valuable therapeutic target in CLL and for IgM-based antibody-drug conjugates as a new targeting platform.

Paradigm shifts in the management of poor-risk chronic lymphocytic leukemia

With the growing complexity of treatment options for chronic lymphocytic leukemia (CLL) and variables that influence the underlying biology of this disease, providing allogeneic stem cell transplant (alloSCT) to appropriate candidates poses a challenge for transplant physicians. Novel small molecule inhibitors hold unprecedented promise for poor-risk subgroups, which will likely alter decision-making and referral patterns for transplant. In this review, we analyze what is known and may still remain true about indications for transplant based on outcomes reported in the literature recently and over the last decade.

Targeting mTORC1-mediated metabolic addiction overcomes fludarabine resistance in malignant B cells

MTOR complex-1(mTORC1) activation occurs frequently in cancers, yet clinical efficacy of rapalogs is limited because of the associated activation of upstream survival pathways. An alternative approach is to inhibit downstream of mTORC1; therefore, acquired resistance to fludarabine (Flu), a purine analogue and antimetabolite chemotherapy, active agent for chronic lymphocytic leukemia (CLL) was investigated. Elevated phospho-p70S6K, also known as RPS6KB1 (ribosomal protein S6 kinase, 70kDa, polypeptide 1) (T389), an mTORC1 activation marker, predicted Flu resistance in a panel of B-cell lines, isogenic Flu-resistant (FluR) derivatives, and primary human CLL cells. Consistent with the anabolic role of mTORC1, FluR cells had higher rates of glycolysis and oxidative phosphorylation than Flu-sensitive (FluS) cells. Rapalogs (everolimus and rapamycin) induced moderate cell death in FluR and primary CLL cells, and everolimus significantly inhibited glycolysis and oxidative phosphorylation in FluR cells. Strikingly, the higher oxidative phosphorylation in FluR cells was not coupled to higher ATP synthesis. Instead, it contributed primarily to an essential, dihydroorotate dehydrogenase catalyzed, step in de novo pyrimidine biosynthesis. mTORC1 promotes pyrimidine biosynthesis by p70S6 kinase-mediated phosphorylation of CAD (carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase; Ser1859) and favors S-phase cell-cycle progression. We found increased phospho-CAD (S1859) and higher S-phase population in FluR cells. Pharmacological inhibition of de novo pyrimidine biosynthesis using N-phosphonacetyl-l-aspartate and leflunomide, RNAi-mediated knockdown of p70S6K, and inhibition of mitochondrial respiration were selectively cytotoxic to FluR, but not FluS, cells. These results reveal a novel link between mTORC1-mediated metabolic reprogramming and Flu resistance identifying mitochondrial respiration and de novo pyrimidine biosynthesis as potential therapeutic targets.

IMPLICATIONS

This study provides the first evidence for mTORC1/p70S6K-dependent regulation of pyrimidine biosynthesis in a relevant disease setting.

Ofatumumab: a novel, fully human anti-CD20 monoclonal antibody for the treatment of chronic lymphocytic leukemia

Ofatumumab is a fully human, IgG anti-CD20 monoclonal antibody codeveloped by GlaxoSmithKline (Brentford, UK) and Genmab (Copenhagen, Denmark). In preclinical studies, ofatumumab exhibited more potent in vitro activity than rituximab against B-cell malignancies and prolonged survival in in vivo animal models compared with rituximab. Ofatumumab is clinically well tolerated with initial infusion reactions being the predominant associated toxicity. Ofatumumab has demonstrated efficacy in relapsed/refractory chronic lymphocytic leukemia (CLL) and has received regulatory approval in both Europe and the USA for treatment of fludarabine and alemtuzumab refractory disease. Single-agent ofatumumab has resulted in overall response rates of 42-51% in relapsed/refractory CLL and up to 80% when combined with chemotherapy. In de novo CLL, overall response rates of 77-78% have been achieved.

Lenalidomide and rituximab for the initial treatment of patients with chronic lymphocytic leukemia: a multicenter clinical-translational study from the chronic lymphocytic leukemia research consortium

PURPOSE

Lenalidomide is an immunomodulatory agent with therapeutic activity in chronic lymphocytic leukemia (CLL). In preclinical models, lenalidomide acted synergistically with rituximab. The CLL Research Consortium initiated a phase II study to evaluate this combination in treatment-naive patients.

PATIENTS AND METHODS

Lenalidomide was initiated at 2.5 mg/day and was escalated based on treatment tolerability to a maximum of 10 mg/day, for 21 days/cycle, for a maximum of seven cycles. Rituximab was administered at the end of cycle 1 and was continued for seven cycles. Patients received allopurinol and aspirin for prophylaxis.

RESULTS

Sixty-nine patients enrolled onto one of two age-specific strata; patients' median age was 56 and 70 years for arms A and B, respectively. Patients in the older-patient stratum more frequently had elevated serum beta-2 microglobulin levels, high-risk Rai stage, and were less likely to complete the maximum planned therapy. Adverse events were similar in the two arms. Nonhematologic toxicity was predominantly at grade 1/2, and neutropenia was the most common hematologic adverse event. The response rate for arm A was 95%, with 20% complete responses (CRs) and 20% nodular partial responses. Of arm B patients, 78% achieved a response, of which 11% were CRs. Median progression-free survival (PFS) was 19 months for the younger cohort and 20 months for the older cohort.

CONCLUSION

Intrapatient dose-escalation was safe. The majority of patients reached the maximum lenalidomide dose and experienced a response to a defined seven-cycle course of lenalidomide and rituximab therapy. Despite differences in baseline characteristics and the response rate between the two strata, the PFS did not differ.

Idelalisib and rituximab in relapsed chronic lymphocytic leukemia

BACKGROUND

Patients with relapsed chronic lymphocytic leukemia (CLL) who have clinically significant coexisting medical conditions are less able to undergo standard chemotherapy. Effective therapies with acceptable side-effect profiles are needed for this patient population.

METHODS

In this multicenter, randomized, double-blind, placebo-controlled, phase 3 study, we assessed the efficacy and safety of idelalisib, an oral inhibitor of the delta isoform of phosphatidylinositol 3-kinase, in combination with rituximab versus rituximab plus placebo. We randomly assigned 220 patients with decreased renal function, previous therapy-induced myelosuppression, or major coexisting illnesses to receive rituximab and either idelalisib (at a dose of 150 mg) or placebo twice daily. The primary end point was progression-free survival. At the first prespecified interim analysis, the study was stopped early on the recommendation of the data and safety monitoring board owing to overwhelming efficacy.

RESULTS

The median progression-free survival was 5.5 months in the placebo group and was not reached in the idelalisib group (hazard ratio for progression or death in the idelalisib group, 0.15; P<0.001). Patients receiving idelalisib versus those receiving placebo had improved rates of overall response (81% vs. 13%; odds ratio, 29.92; P<0.001) and overall survival at 12 months (92% vs. 80%; hazard ratio for death, 0.28; P=0.02). Serious adverse events occurred in 40% of the patients receiving idelalisib and rituximab and in 35% of those receiving placebo and rituximab.

CONCLUSIONS

The combination of idelalisib and rituximab, as compared with placebo and rituximab, significantly improved progression-free survival, response rate, and overall survival among patients with relapsed CLL who were less able to undergo chemotherapy. (Funded by Gilead; ClinicalTrials.gov number, NCT01539512.).

Ibrutinib (PCI-32765) in chronic lymphocytic leukemia

B-cell receptor (BCR) signaling is essential for chronic lymphocytic leukemia (CLL) cell survival. Many kinases in the BCR signaling pathway are being studied as potential therapeutic targets. Ibrutinib (PCI-32765) is a novel first-in-class selective inhibitor of Bruton tyrosine kinase. Preclinical evidence suggests that ibrutinib inhibits CLL cell survival and proliferation and affects CLL cell migration and homing. Early clinical data in patients with CLL and non-Hodgkin lymphoma is encouraging. It is likely that ibrutinib and other drugs targeting the BCR pathway will become an integral component of CLL therapy.

Auranofin induces lethal oxidative and endoplasmic reticulum stress and exerts potent preclinical activity against chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) exhibits high remission rates after initial chemoimmunotherapy, but with relapses with treatment, refractory disease is the most common outcome, especially in CLL with the deletion of chromosome 11q or 17p. In addressing the need of treatments for relapsed disease, we report the identification of an existing U.S. Food and Drug Administration-approved small-molecule drug to repurpose for CLL treatment. Auranofin (Ridaura) is approved for use in treating rheumatoid arthritis, but it exhibited preclinical efficacy in CLL cells. By inhibiting thioredoxin reductase activity and increasing intracellular reactive oxygen species levels, auranofin induced a lethal endoplasmic reticulum stress response in cultured and primary CLL cells. In addition, auranofin displayed synergistic lethality with heme oxygenase-1 and glutamate-cysteine ligase inhibitors against CLL cells. Auranofin overcame apoptosis resistance mediated by protective stromal cells, and it also killed primary CLL cells with deletion of chromosome 11q or 17p. In TCL-1 transgenic mice, an in vivo model of CLL, auranofin treatment markedly reduced tumor cell burden and improved mouse survival. Our results provide a rationale to reposition the approved drug auranofin for clinical evaluation in the therapy of CLL.

Immunotherapy for chronic lymphocytic leukemia in the era of BTK inhibitors

Understanding the pathogenesis of CLL has uncovered a plethora of novel targets for human application of monoclonal antibodies, engineered T cells, or inhibitors of signal transduction pathways. The B-cell receptor signaling pathway is being actively explored as a therapeutic target in CLL. Ibrutinib, an inhibitor of Bruton's tyrosine kinase is showing impressive responses in heavily pre-treated high-risk CLL, whether alone or in combination with MoAbs or chemotherapy. Other key components of the BCR pathway, namely PI3K-δ, are also being targeted with novel therapies with promising results as well. Future trials would likely evaluate ibrutinib in the front-line setting. Moreover, improvements in allogeneic HCT mostly by continuing to reduce associated toxicity as well as incorporating cellular therapies such as autologous CLL tumor vaccines, among others, will continue to expand. This is also the case for the next generation of chimeric antigen receptor therapy for CLL once genetically modified T cells are available at broad scale and with improved efficacy. As our ability to further refine and integrate these therapies continues to improve, and we gain further knowledge from gene sequencing, we anticipate that treatment algorithms will continue to be revised to a more personalized approach to treat this disease with improved efficacy and devoid of unnecessary toxicity.

Interactions between comorbidity and treatment of chronic lymphocytic leukemia: results of German Chronic Lymphocytic Leukemia Study Group trials

This study investigated the impact of comorbidity in 555 patients with chronic lymphocytic leukemia enrolled in two trials of the German Chronic Lymphocytic Leukemia Study Group on first-line treatment with fludarabine plus cyclophosphamide, fludarabine, or chlorambucil. Patients with two or more comorbidities and patients with less than two comorbidities differed in overall survival (71.7 versus 90.2 months; P<0.001) and progression-free survival (21.0 versus 31.5 months; P<0.01). After adjustment for other prognostic factors and treatment, comorbidity maintained its independent prognostic value in a multivariate Cox regression analysis. Chronic lymphocytic leukemia was the major cause of death in patients with two or more comorbidities. Disease control in patients with two or more comorbidities was better with fludarabine plus cyclophosphamide than with fludarabine treatment, but not with fludarabine compared to chlorambucil treatment. These results give insight into interactions between comorbidity and therapy of chronic lymphocytic leukemia and suggest that durable control of the hematologic disease is most critical to improve overall outcome of patients with increased comorbidity. The registration numbers of the trials reported are NCT00276848 and NCT00262795.

Poly(ADP-ribose) polymerase inhibitor CEP-8983 synergizes with bendamustine in chronic lymphocytic leukemia cells in vitro

DNA repair aberrations and associated chromosomal instability is a feature of chronic lymphocytic leukemia (CLL). To evaluate if DNA repair insufficiencies are related to methylation changes, we examined the methylation of nine promoter regions of DNA repair proteins by bisulfide sequencing in 26 CLL primary samples and performed quantitative PCR on a subset of samples to examine BRCA1 expression. We also investigated if changes in cytogenetic or expression level of DNA repair proteins led to changes in sensitivity to a novel PARP inhibitor, CEP-8983, alone and in combination with bendamustine. No changes in promoter methylation were identified in BRCA1, BRCA2, FANC-C, FANC-F, FANC-L, ATM, MGMT, hMLH1 and H2AX except for two cases of minor BRCA1 hypermethylation. CLL samples appeared to have reduced BRCA1 mRNA expression uniformly in comparison to non-malignant lymphocytes irrespective of promoter hypermethylation. CEP-8983 displayed single agent cytotoxicity and the combination with bendamustine demonstrated synergistic cytotoxicity in the majority of CLL samples. These results were consistent across cytogenetic subgroups, including 17p deleted and previously treated patients. Our results provide rationale for further exploration of the combination of a PARP inhibitor and DNA damaging agents as a novel therapeutic strategy in CLL.

Ibrutinib as initial therapy for elderly patients with chronic lymphocytic leukaemia or small lymphocytic lymphoma: an open-label, multicentre, phase 1b/2 trial

BACKGROUND

Chemoimmunotherapy has led to improved numbers of patients achieving disease response, and longer overall survival in young patients with chronic lymphocytic leukaemia; however, its application in elderly patients has been restricted by substantial myelosuppression and infection. We aimed to assess safety and activity of ibrutinib, an orally administered covalent inhibitor of Bruton tyrosine kinase (BTK), in treatment-naive patients aged 65 years and older with chronic lymphocytic leukaemia.

METHODS

In our open-label phase 1b/2 trial, we enrolled previously untreated patients at clinical sites in the USA. Eligible patients were aged at least 65 years, and had symptomatic chronic lymphocytic leukaemia or small lymphocytic lymphoma requiring therapy. Patients received 28 day cycles of once-daily ibrutinib 420 mg or ibrutinib 840 mg. The 840 mg dose was discontinued after enrolment had begun because comparable activity of the doses has been shown. The primary endpoint was the safety of the dose-fixed regimen in terms of frequency and severity of adverse events for all patients who received treatment. This study is registered with ClinicalTrials.gov, number NCT01105247.

FINDINGS

Between May 20, 2010, and Dec 18, 2012, we enrolled 29 patients with chronic lymphocytic leukaemia and two patients with small lymphocytic lymphoma. Median age was 71 years (range 65-84), and 23 (74%) patients were at least 70 years old. Toxicity was mainly of mild-to-moderate severity (grade 1-2). 21 (68%) patients had diarrhoea (grade 1 in 14 [45%] patients, grade 2 in three [10%] patients, and grade 3 in four [13%] patients). 15 (48%) patients developed nausea (grade 1 in 12 [39%] patients and grade 2 in three [10%] patients). Ten (32%) patients developed fatigue (grade 1 in five [16%] patients, grade 2 in four [13%] patients, and grade 3 in one [3%] patient). Three (10%) patients developed grade 3 infections, although no grade 4 or 5 infections occurred. One patient developed grade 3 neutropenia, and one developed grade 4 thrombocytopenia. After a median follow-up of 22.1 months (IQR 18.4-23.2), 22 (71%) of 31 patients achieved an objective response (95% CI 52.0-85.8); four patients (13%) had a complete response, one patient (3%) had a nodular partial response, and 17 (55%) patients had a partial response.

INTERPRETATION

The safety and activity of ibrutinib in elderly, previously untreated patients with symptomatic chronic lymphocytic leukaemia, or small lymphocytic lymphoma is encouraging, and merits further investigation in phase 3 trials.

FUNDING

Pharmacyclics, Leukemia and Lymphoma Society, D Warren Brown Foundation, Mr and Mrs Michael Thomas, Harry Mangurian Foundation, P50 CA140158 to Prof J C Byrd MD.

CAR-modified anti-CD19 T cells for the treatment of B-cell malignancies: rules of the road

INTRODUCTION

Malignancies of the B lymphocyte or its precursor include B-cell non-Hodgkin lymphoma as well as chronic and acute lymphoid leukemias. These are among the most common hematologic malignancies and many patients with B-cell malignancies are incurable. Although most patients initially respond to first-line treatment, relapse is frequent and is associated with a poor prognosis. T cells that are genetically engineered to express chimeric antigen receptors (CARs) recognizing the B-cell-associated molecule CD19 have emerged as a potentially potent and exciting therapeutic modality in recent years.

AREAS COVERED

This review explores the current peer-reviewed publications in the field and a discussion of expert opinion.

EXPERT OPINION

Genetic engineering of T cells has become clinically feasible and appears to be safe. Here we provide an insight into the process of patient selection, engineered T-cell production, infusion procedure, expected toxicities and efficacy of this exciting approach as it is practiced in the treatment of B-cell malignancies. Anti-CD19-redirected T cells likely represent the vanguard of an exciting new approach to treating cancer.

Rituximab-based chemoimmunotherapy prolongs survival of patients with chronic lymphocytic leukemia independently of the time of administration

BACKGROUND

The combination of purine analogues (PA) and rituximab (chemoimmunotherapy) is considered the treatment of choice for CLL. The aim of this study was to determine whether chemoimmunotherapy prolonged the overall survival in patients with CLL from a single center.

PATIENTS AND METHODS

From 1980 to 2010, 273 patients with CLL received: (1) PA (n = 159); and (2) PA plus rituximab (PA+R) (n = 114). All treated patients were included in the analysis, regardless of time at which treatment was administered, duration of therapy, and response.

RESULTS

Patients from the PA and PA+R groups were well balanced for demographic, clinical, and biologic features. At 8 years, the survival from diagnosis of the PA+R group was 88% (95% confidence interval [CI], 82-94%) compared with 68% (95% CI, 60-76%) for the PA group (P < .001). When survival of patients treated with PA+R was analyzed according to the time of treatment administration (first- [n = 55] vs. second or more lines [n = 59]), no significant differences were observed (8-year overall survival 89% vs. 87%, respectively; P = .8).

CONCLUSION

Chemoimmunotherapy prolonged the survival of patients with CLL and this effect was independent of the phase of the disease at which treatment was given.