Chemoimmunotherapy with O-FC in previously untreated patients with chronic lymphocytic leukemia. Blood. 2011;117:6450-6458. [PMID: 21498674 DOI: 10.1182/blood-2010-12-323980]

Immune Dysfunction and Infection - Interaction between CLL and Treatment: A Reflection on Current Treatment Paradigms and Unmet Needs

BACKGROUND

Chronic lymphocytic leukemia (CLL) is a hematological malignancy characterized by immune dysfunction, which significantly contributes to increased morbidity and mortality due to infections.

SUMMARY

Advancement in therapeutic strategies based on combination chemoimmunotherapy and targeted treatment have increased life expectancy for patients affected by CLL. However, mortality and morbidity due to infection showed no improvement over the last decades. Although therapy options are highly efficient in targeting leukemic cells, several studies highlighted the interactions of different treatments with the tumor microenvironment immune components, significantly impacting their clinical efficacy and fostering increased risk of infections.

KEY MESSAGES

Given the profound immune dysfunction caused by CLL itself, treatment can thus represent a double-edged sword. Thus, it is essential to increase our understanding and awareness on how conventional therapies affect the disease-microenvironment-infection axis to ensure the best personalized strategy for each patient. This requires careful consideration of the advantages and disadvantages of efficient treatments, whether chemoimmunotherapy or targeted combinations, leading to risk of infectious complications. To this regard, our machine learning-based algorithm CLL Treatment-Infection Model, currently implemented into the local electronic health record system for Eastern Denmark, aims at early identification of patients at high risk of serious infections (PreVent-ACaLL; NCT03868722). We here review strategies for management of immune dysfunction and infections in CLL.

Emerging Therapies in CLL in the Era of Precision Medicine

Over the past decade, the treatment landscape of CLL has vastly changed from the conventional FC (fludarabine and cyclophosphamide) and FCR (FC with rituximab) chemotherapies to targeted therapies, including inhibitors of Bruton tyrosine kinase (BTK) and phosphatidylinositol 3-kinase (PI3K) as well as inhibitors of BCL2. These treatment options dramatically improved clinical outcomes; however, not all patients respond well to these therapies, especially high-risk patients. Clinical trials of immune checkpoint inhibitors (PD-1, CTLA4) and chimeric antigen receptor T (CAR T) or NK (CAR NK) cell treatment have shown some efficacy; still, long-term outcomes and safety issues have yet to be determined. CLL remains an incurable disease. Thus, there are unmet needs to discover new molecular pathways with targeted or combination therapies to cure the disease. Large-scale genome-wide whole-exome and whole-genome sequencing studies have discovered genetic alterations associated with disease progression, refined the prognostic markers in CLL, identified mutations underlying drug resistance, and pointed out critical targets to treat the disease. More recently, transcriptome and proteome landscape characterization further stratified the disease and revealed novel therapeutic targets in CLL. In this review, we briefly summarize the past and present available single or combination therapies, focusing on potential emerging therapies to address the unmet clinical needs in CLL.

SOHO State of the Art Updates and Next Questions | Infections in Chronic Lymphocytic Leukemia Patients: Risks and Management

Although chronic lymphocytic leukemia (CLL) is a malignancy characterized by accumulation of tumor cells in the blood, bone marrow, lymph nodes and secondary lymphoid tissues, the hallmark of the disease and the major cause of death for patients with CLL is actually immune dysfunction and associated infections. Despite improvement in treatment based on combination chemoimmunotherapy and targeted treatment with BTK and BCL-2 inhibitors leading to longer overall survival for patients with CLL, the mortality due to infections have not improved over the last 4 decades. Thus, infections are now the main cause of death for patients with CLL, posing threats to the patient whether during the premalignant state of monoclonal B lymphocytosis (MBL), during the watch & wait phase for treatment naïve patients, or upon treatment in terms of chemoimmunotherapy or targeted treatment. To test whether the natural history of immune dysfunction and infections in CLL can be changed, we have developed the machine learning based algorithm CLL-TIM.org to identify these patients. The CLL-TIM algorithm is currently being used for selection of patients for the clinical trial PreVent-ACaLL (NCT03868722), testing whether short-term treatment with the BTK inhibitor acalabrutinib and the BCL-2 inhibitor venetoclax can improve immune function and decrease the risk of infections for this high-risk patient population. We here review the background for and management of infectious risks in CLL.

Treatment Approaches to Chronic Lymphocytic Leukemia With High-Risk Molecular Features

The clinical course of chronic lymphocytic leukemia (CLL) is highly variable. Over the past decades, several cytogenetic, immunogenetic and molecular features have emerged that identify patients suffering from CLL with high-risk molecular features. These biomarkers can clearly aid prognostication, but may also be capable of predicting the efficacy of various treatment strategies in subgroups of patients. In this narrative review, we discuss treatment approaches to CLL with high-risk molecular features. Specifically, we review and provide a comprehensive overview of clinical trials evaluating the efficacy of chemotherapy, chemoimmunotherapy and novel agent-based treatments in CLL patients with TP53 aberrations, deletion of the long arm of chromosome 11, complex karyotype, unmutated IGHV, B cell receptor stereotypy, and mutations in NOTCH1 or BIRC3. Furthermore, we discuss future pharmaceutical and immunotherapeutic perspectives for CLL with high-risk molecular features, focusing on agents currently under investigation in clinical trials.

Infectious Complications of Biological and Small Molecule Targeted Immunomodulatory Therapies

The past 2 decades have seen a revolution in our approach to therapeutic immunosuppression. We have moved from relying on broadly active traditional medications, such as prednisolone or methotrexate, toward more specific agents that often target a single receptor, cytokine, or cell type, using monoclonal antibodies, fusion proteins, or targeted small molecules. This change has transformed the treatment of many conditions, including rheumatoid arthritis, cancers, asthma, and inflammatory bowel disease, but along with the benefits have come risks. Contrary to the hope that these more specific agents would have minimal and predictable infectious sequelae, infectious complications have emerged as a major stumbling block for many of these agents. Furthermore, the growing number and complexity of available biologic agents makes it difficult for clinicians to maintain current knowledge, and most review articles focus on a particular target disease or class of agent. In this article, we review the current state of knowledge about infectious complications of biologic and small molecule immunomodulatory agents, aiming to create a single resource relevant to a broad range of clinicians and researchers. For each of 19 classes of agent, we discuss the mechanism of action, the risk and types of infectious complications, and recommendations for prevention of infection.

Investigational treatments for chronic lymphocytic leukemia: a focus on phase 1 and 2 clinical trials

Introduction: During recent years, the introduction of novel drugs, particularly small molecule inhibitors, has led to remarkable progress in both previously untreated and relapsed/refractory (RR) patients in chronic lymphocytic leukemia (CLL). However, further research is necessary to find an optimal cure that responds to the individual needs of the patient. Areas covered: This review discusses new agents in phase 1 and 2 clinical trials currently underway in CLL patients. A literature review of the MEDLINE database for articles in English concerning novel drugs, clinical trials, phase 1, phase 2 and CLL was conducted via PubMed. Publications from 2000 through January 2020 were scrutinized. Conference proceedings from the previous five years of the American Society of Hematology, European Hematology Association and American Society of Clinical Oncology were searched manually. Additional relevant publications were obtained by reviewing the references from the chosen articles. The search also included clinical trials registered in clinicaltrials.gov. Expert opinion: The use of BTK and PI3Kδ inhibitors and BCL-2 antagonist have changed the treatment strategy of CLL. Several clinical trials with novel, unapproved agents are currently ongoing. Their findings should define the role of these novel drugs in the treatment of patients with previously untreated and RR CLL.

Advances in targeted therapy for malignant lymphoma

The incidence of lymphoma has gradually increased over previous decades, and it ranks among the ten most prevalent cancers worldwide. With the development of targeted therapeutic strategies, though a subset of lymphoma patients has become curable, the treatment of refractory and relapsed diseases remains challenging. Many efforts have been made to explore new targets and to develop corresponding therapies. In addition to novel antibodies targeting surface antigens and small molecular inhibitors targeting oncogenic signaling pathways and tumor suppressors, immune checkpoint inhibitors and chimeric antigen receptor T-cells have been rapidly developed to target the tumor microenvironment. Although these targeted agents have shown great success in treating lymphoma patients, adverse events should be noted. The selection of the most suitable candidates, optimal dosage, and effective combinations warrant further investigation. In this review, we systematically outlined the advances in targeted therapy for malignant lymphoma, providing a clinical rationale for mechanism-based lymphoma treatment in the era of precision medicine.

Anti-CD20 monoclonal antibodies: reviewing a revolution

Since the inception of rituximab in the 1990s, anti-CD20 monoclonal antibodies have revolutionised the treatment of B cell hematological malignancies and have become a cornerstone of modern gold-standard practice. Additionally, the potent efficacy of these agents in depleting the B cell compartment has been used in the management of a broad array of autoimmune diseases. Multiple iterations of these agents have been investigated and are routinely used in clinical practice. In this review, we will discuss the physiology of CD20 and its attractiveness as a therapeutic target, as well as the pharmacology, pre-clinical and clinical data for the major anti-CD20 monoclonal antibodies: rituximab, obinutuzumab and ofatumumab.

The use of ofatumumab in the treatment of B-cell malignancies

Ofatumumab has been extensively studied in the treatment of B-cell malignancies. Currently, it has been approved for the treatment of chronic lymphocytic leukemia in a number of different situations. However, there is still no compelling evidence confirming the superiority of ofatumumab over rituximab in vivo. In this article, we summarize the currently available clinical data supporting the use of ofatumumab in the treatment of B-cell malignancies. The clinical studies were searched from clinicaltrials.gov with the key words ofatumumab, HuMax-CD20. Out of 115 trials available, studies for B-cell malignancies were selected, followed by selection of completed studies with results and active ongoing studies. The results from completed studies were thoroughly analyzed and active ongoing studies were listed in tables.

Current Treatment of Chronic Lymphocytic Leukemia

OPINION STATEMENT

A number of new treatment options have recently emerged for chronic lymphocytic leukemia (CLL) patients, including the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib, phosphatidylinositol-3-kinase (PI3K) delta isoform inhibitor idelalisib combined with rituximab, the Bcl-2 antagonist venetoclax, and the new anti-CD20 antibodies obinutuzumab and ofatumumab. Most of these agents are already included into treatment algorithms defined by international practice guidelines, but more clinical investigations are needed to answer still remaining questions. Ibrutinib was proven as a primary choice for patients with the TP53 gene deletion/mutation, who otherwise have no active treatment available. Idelalisib with rituximab is also an active therapy, but due to increased risk of serious infections, its use in first-line treatment is limited to patients for whom ibrutinib is not an option. A new indication for ibrutinib was recently approved for older patients with comorbidities, as an alternative to the already existing indication for chlorambucil with obinutuzumab. The use of kinase inhibitors is already well established in recurrent/refractory disease. Immunochemotherapy with fludarabine, cyclophosphamide, rituximab (FCR) remains a major first-line option for many CLL patients without the TP53 gene deletion/mutation, and who have no significant comorbidities or history of infections, and is particularly effective in patients with favorable features including mutated IGHV status. There are a number of issues regarding novel therapies for CLL that need further investigation such as optimum duration of treatment with kinase inhibitors, appropriate sequencing of novel agents, mechanisms of resistance to inhibitors and response to class switching after treatment failure, along with the potential role of combinations of targeted agents.

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.

Dancing partners at the ball: Rational selection of next generation anti-CD20 antibodies for combination therapy of chronic lymphocytic leukemia in the novel agents era

The anti-CD20 antibodies represent a major advancement in the therapeutic options available for chronic lymphocytic leukemia. The addition of rituximab, ofatumumab and obinutuzumab to various chemotherapy regimens has led to considerable improvements in both response and survival. Ocaratuzumab, veltuzumab and ublituximab are currently being explored within the trial setting. We review the current status of these antibodies, and discuss how their mechanisms of action may impact on the choice of combinations with novel small molecule agents.

Ofatumumab combined with chlorambucil for previously untreated chronic lymphocytic leukemia: a phase I/II, open-label study in Japan

Elderly/comorbid patients with chronic lymphocytic leukemia (CLL) require low-toxicity treatments. Internationally, the standard treatment for such patients is chlorambucil and an anti-CD20 therapy; however, chlorambucil is not approved in Japan. The aim of the present study was to evaluate the safety, efficacy and pharmacokinetics of ofatumumab in combination with chlorambucil in Japanese patients with previously untreated CLL who were inappropriate for fludarabine-based therapy. Ten patients were enrolled and treated in this study, all of whom received at least one dose of the study drugs. The tolerability of the treatment was confirmed initially with three patients. The overall response rate was 50%, as determined by the Independent Review Committee (IRC) with computerized tomography. All patients were alive at follow-up, and only one patient had progressive disease. The most common treatment-related adverse events (AEs) were thrombocytopenia (n = 10), neutropenia (n = 9) and rash (n = 6). One grade 3 serious AE related to the study drug occurred (hypoxia). The results indicate that ofatumumab combined with chlorambucil is an effective treatment for Japanese CLL patients, with a manageable safety profile.

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.

Ofatumumab plus fludarabine and cyclophosphamide in relapsed chronic lymphocytic leukemia: results from the COMPLEMENT 2 trial

In this multicenter, open-label, phase III study, patients with relapsed chronic lymphocytic leukemia (CLL) were randomized (1:1) to receive ofatumumab plus fludarabine and cyclophosphamide (OFA + FC) or FC alone; the primary endpoint being progression-free survival (PFS) assessed by an independent review committee (IRC). Between March 2009 and January 2012, 365 patients were randomized (OFA + FC: n = 183; FC: n = 182). Median IRC-assessed PFS was 28.9 months with OFA + FC versus 18.8 months with FC (hazard ratio = 0.67; 95% confidence interval, 0.51-0.88; p = .0032). Grade ≥3 adverse events (≤60 days after last dose) were reported in 134 (74%) OFA + FC-treated patients compared with 123 (69%) FC-treated patients. Of these, neutropenia was the most common (89 [49%] vs. 64 [36%]). OFA + FC improved PFS with manageable safety for patients with relapsed CLL compared with FC alone, thus providing an alternative treatment option for patients with relapsed CLL.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT00824265).

A phase 2, multicenter study investigating ofatumumab and bendamustine combination in patients with untreated or relapsed CLL

The purpose of this study is to assess the safety and efficacy of the combination of ofatumumab and bendamustine in patients with previously untreated or relapsed chronic lymphocytic leukemia. Patients received IV ofatumumab (cycle 1: 300 mg day 1 and 1,000 mg day 8; cycles 2-6: 1,000 mg on day 1 every 28 days) and IV bendamustine 90 mg m(-2) (previously untreated) or 70 mg m(-2) (relapsed) on days 1 and 2 of each 28-day cycle, for up to 6 cycles. Forty-four previously untreated and 53 relapsed patients were enrolled. Median age was 62.5 years (previously untreated) and 68 years (relapsed); relapsed patients had received a median of 1 (range 1-11) prior therapy. The investigator-assessed overall response rate was 95% (43% complete response [CR]) for the previously untreated, and 74% (11% CR) for the relapsed patients. The regimen was well tolerated with 89% (previously untreated) and 85% (relapsed patients) receiving all 6 cycles. No unexpected toxicities were reported. Grade 3/4 events occurred in 57% of previously untreated, and 72% of relapsed patients. At ∼29 months' follow-up, the median progression-free survival (PFS) was not reached for the previously untreated population, and the 28-month PFS estimate was 72.3%. The median PFS for the relapsed population was 22.5 months (95% CI: 14.0-27.3 months). The combination of ofatumumab and bendamustine was well tolerated and effective in these previously untreated or relapsed populations. Am. J. Hematol. 91:900-906, 2016. © 2016 Wiley Periodicals, Inc.

Associations of ofatumumab exposure and treatment outcomes in patients with untreated CLL receiving chemoimmunotherapy

Relationships between patient characteristics, ofatumumab pharmacokinetics, and treatment outcomes were investigated in this phase 2 trial of ofatumumab plus fludarabine and cyclophosphamide (FC) in untreated chronic lymphocytic leukemia. Patients were randomized 1:1 to receive 500 or 1000 mg ofatumumab (Cycle 1; 300 mg) plus FC every 4 weeks for six cycles. Median C_max and C_trough values were similar at Cycle 1 regardless of the ultimate clinical outcome. At later doses, these values were higher for patients with complete response (CR) than for other patients. Higher C_max and C_trough values at Cycles 3 and 6 were significantly associated with an increased likelihood of CR, whereas ofatumumab pharmacokinetics were not associated with an objective response (OR) on the basis of univariate analyses. Multivariate analyses indicated that baseline patient/disease factors were predominantly associated with CR (17p status) or OR (bulky lymphadenopathy, gender, and serum thymidine kinase), rather than ofatumumab pharmacokinetics.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT00410163).

Ofatumumab plus chlorambucil as a first-line therapy in less fit patients with chronic lymphocytic leukemia: analysis of COMPLEMENT1 and other monoclonal antibodies association data

The management of patients with chronic lymphocytic leukemia (CLL) has radically improved over the last few years with the addition of anti-CD20 monoclonal antibodies (MoAbs) to chemotherapy. Chlorambucil has been considered for decades as a suitable therapeutic option for frail patients. Taking into account the advantage offered by the addition of MoAbs to chemotherapy, different studies up to now have explored the feasibility of chlorambucil-based chemoimmunotherapies in treatment-naïve CLL. COMPLEMENT1 is a prospective, randomized, open-label trial evaluating the efficacy and safety of ofatumumab added to chlorambucil, compared with chlorambucil in monotherapy, in the setting of untreated patients with CLL considered unsuitable for a fludarabine-based approach. Progression-free survival was significantly longer in the chemoimmunotherapy arm when compared with the single-agent chlorambucil (22.4 months versus 13.1 months). Response rate and quality were also improved in the combination arm. Furthermore, the addition of ofatumumab did not lead to an unmanageable toxicity. While the employment of anti-CD20 antibodies represents an advantage in the treatment of the CLL symptomatic population, at present different patient selection and treatment schedules do not allow a reliable comparison between chlorambucil-based regimens. The addition of ofatumumab to chlorambucil represents a further therapeutic gain in CLL. Longer follow up and direct comparison with other MoAbs are warranted to establish the preferred first-line treatment in elderly and unfit patients.

Chronic lymphocytic leukemia: a clinical review including Korean cohorts

Only 5th decade ago, chronic lymphocytic leukemia (CLL) was only recognized as disease group of presenting features like peripheral lymphocytosis, organomegaly including of splenomegaly. As understanding of disease biology and molecular diagnostic tools are getting improved gradually, characterization of variation in CLL's clinical courses was facilitated, resulting in better risk stratification and targeted treatments. Consequently multiple new targeted agents have been used in treatment of CLL, it makes improved clinical outcome. Rituximab containing chemoimmunotherapy (combination of rituximab, fludarabine, and cyclophosphamide) have shown better overall response rate and progression-free survival on fit patients' group in front-line setting, result in standard first-line therapeutic option for CLL. Furthermore, after introducing that the B-cell receptor is crucial for the evolution and progression of CLL, emerging treatments targeting highly activated surface antigens and oncogenic signaling pathways have been associated with several successes in recent decades. These include new anti-CD 20 monoclonal antibody (obinutuzumab), the bruton tyrosine kinase inhibitor (ibrutinib), the phosphatidylinositol 3-kinase inhibitor (idelalisib), and B-cell CLL/lymphoma 2 inhibitor (ABT-199 and ABT-263). So, we discuss not only general pathophysiology of CLL, but also rapidly advancing treatment strategies that are being studied or approved for treatment of CLL.

Chronic lymphocytic leukemia (CLL)-Then and now

The field of chronic lymphocytic leukemia (CLL) has witnessed considerable change since the time clinical staging was introduced in clinical practice in 1975. Over the years, the prognostication in CLL has expanded with the addition in late 90s of mutational status of variable region of immunoglobulin heavy chain (IGHV), and chromosomal analyses using fluorescent in situ hybridization (FISH). More recently, stereotypy of BCR (B cell receptor) and whole exome sequencing (WES) based discovery of specific mutations such as NOTCH1, TP53, SF3B1, XPO-1, BIRC3, ATM, and RPS15 further refined the current prognostication system in CLL. In therapy, the field of CLL has seen major changes from oral chlorambucil and steroids prior to 1980s, to chemo-immunotherapy (CIT) with fludarabine, cyclophosphamide, rituximab (FCR) to the orally administered targeted therapeutic agents inhibiting kinases in the B cell receptor (BCR) signaling pathway such as Ibrutinib (BTK inhibitor) and Idelalisib (p110 PI3Kδ inhibitor) and novel anti-CD20 mAb's (monoclonal antibodies) such as obinutuzumab. This progress is continuing and other targeted therapeutics such as Bcl2 antagonists (Venetoclax or ABT-199) and finally chimeric antigen receptor against T cells (CART) are in the process of being developed. This review is an attempt to summarize the major benchmarks in the prognostication and in the therapy of CLL. The topic allocated to us by Dr Ayalew Tefferi and Dr Carlo Brugnara is very appropriate to reminisce what our understanding of chronic lymphocytic leukemia (CLL) was in 1976 and how rapidly have the advances occurring in this field affected the patients with CLL.

An update on current and prospective immunotherapies for chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common leukemia. Combined agent chemotherapy is the current standard front-line treatment for physically fit patients with CLL. Use of chemotherapy can be complicated by significant toxicity, especially in patients with advanced age or comorbid conditions. Moreover, patients may relapse and become refractory to further chemotherapy. Immunotherapy targets the aberrant immunological processes in CLL without the toxicity of chemotherapy. Immunotherapeutic strategies can also be combined with chemotherapy to improve response rates in this incurable disease. In this review, we evaluate current and future immune-based options in the treatment of CLL.

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.

New developments in the management of chronic lymphocytic leukemia: role of ofatumumab

Ofatumumab is one of the three anti-CD20 monoclonal antibodies currently available for the treatment of chronic lymphocytic leukemia (CLL). The US Food and Drug Administration (FDA) approved the use of ofatumumab in patients with CLL refractory to fludarabine and alemtuzumab in 2009, and the European Medicines Agency (EMA) granted approval for the same indication in 2010. Subsequent positive results of ofatumumab in combination with chlorambucil in treatment-naïve patients led the FDA in April 2014 to approve the use of this combination for first-line treatment of patients with CLL for whom fludarabine-based therapy is considered inappropriate. Later that year, the EMA approved the use of ofatumumab in combination with chlorambucil or bendamustine for the same indication. Ofatumumab has also shown potential as maintenance therapy for patients with relapsed CLL; an application to broaden the label for ofatumumab as maintenance therapy was submitted earlier this year to the EMA and FDA. Finally, ofatumumab has shown promising activity in combination with ibrutinib or idelalisib in relapsed/refractory CLL patients; combinations of ofatumumab with B-cell-receptor pathway inhibitors could represent another potential use of this antibody in the near future.

Safety and efficacy of different lenalidomide starting doses in patients with relapsed or refractory chronic lymphocytic leukemia: results of an international multicenter double-blinded randomized phase II trial

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

Targeted therapy for chronic lymphocytic leukemia: current status and future directions

The majority of patients with chronic lymphocytic leukemia (CLL) respond to chemo-immunotherapy. However, long-term remission remains elusive and the majority of patients will die of complications related to CLL. In this review we discuss the recent developments in targeted therapy for CLL. Targeted therapy has evolved beyond the cell surface targeting of CD20 with rituximab. Our review focuses on the evolution of antibody therapy in CLL, strategies to target effector T cells to the tumor, inhibition of the B-cell receptor signaling pathway, and finally targeting the mediators of apoptosis. With our improved understanding of the biology of CLL, the evolution of targeted therapy has resulted in significant clinical responses in patients who are refractory to traditional treatment options and holds the potential for a future where we can manage this disease without chemotherapy.

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.

Development of Novel Anti-Cd20 Monoclonal Antibodies and Modulation in Cd20 Levels on Cell Surface: Looking to Improve Immunotherapy Response

Rituximab has been revolutionized and validated CD20 targeting monoclonal antibody. Although, it is widely used for lymphoma therapy and many patients have been benefited. However significant numbers of patients are refractory or developed resistance to current therapies due to low level of CD20 expression and/or availability on cells surface. Thus development of novel anti-CD20 mAbs with great cell killing ability and enhance CD20 levels on cell surface can potentially exploit lymphoma therapy. In this scenario, we are summarizing the recently developed mAbs against CD20 and compounds that have ability to induce CD20 expression at significant level. We also are providing information regarding combination strategy for use of radiation and anti-CD20 mAbs in vitro. However, it will need to be determined by rigorous at pre-clinical and clinic testing. We hope this review will be beneficial for current research in the area of immunotherapy or radio-immunotherapy.

Clinical utility and patient considerations in the use of ofatumumab in chronic lymphocytic leukemia

Treatment aim for chronic lymphocytic leukemia has been radically changed over the past years from providing only a palliative approach to reaching disease eradication and improving survival. Ofatumumab is a monoclonal humanized antibody with peculiar in vitro and in vivo properties, at present approved for double fludarabine and alemtuzumab refractory chronic lymphocytic leukemia. Its efficacy in this subset of patients, who typically have an unfavorable prognosis, facilitated its use in different Phase II and III trials. Ofatumumab as single agent or combined with chemotherapeutic or biologic agents, led to sundry results in the setting of both previously treated or untreated patients. Its role in maintenance therapy is also under investigation. Further advances concerning ofatumumab administration as first line therapy in combination with chlorambucil, came recently from the COMPLEMENT 1 study. Results from this trial will open the door to new perspectives of its use in treatment-naïve patients. Ofatumumab was well tolerated in almost all the studies, with the main adverse events relating mostly to infusion reaction. Hematologic toxicity, especially neutropenia, was also common. A significant improvement in patients' quality of life was reported following ofatumumab treatment and this was mainly due to its effect on constitutional symptoms. Nevertheless, some concerns remain regarding the long-term efficacy of the drug in terms of response duration and survival. The real strength of this drug needs to be confirmed by further studies and direct comparative trials.

Treatment of chronic lymphocytic leukemia with monoclonal antibodies, where are we heading?

Chronic lymphocytic leukemia (CLL) is the most prevalent leukemia in the western world and monoclonal antibodies (mAbs) are important part of CLL treatment. The goal of this article was to summarize current literature on the position of mAbs in CLL treatment and to mention factors influencing effectiveness of mAbs in CLL. Several new mAbs have been developed and investigated in CLL over the past few years. Mainly anti-CD20 monoclonal antibodies are still used routinely in CLL therapy. Unfortunately, the clinical application of mAbs needs to be further improved. Novel combinations and sequences of mAbs with other compounds need to be studied in clinical trials in order to increase overall response rate and prolong remission duration. Mechanisms of action of mAbs or mechanisms of resistance to mAbs have to be also investigated to predict effectiveness of mAb in particular patient.

A review of monoclonal antibody therapies in lymphoma

Monoclonal antibodies (moAb) represent a novel way of delivering therapy through specific target antigens expressed on lymphoma cells and minimizes the collateral damage that is common with conventional chemotherapy. The paradigm of this approach is the targeting of CD20 by rituximab. Since its FDA approval in 1997, rituximab has become the standard of care in almost every line of therapy in most B-cell lymphomas. This review will briefly highlight some of the key rituximab trials while looking more closely at the evidence that is bringing other antibodies, including next generation anti-CD20 moAbs, and anti-CD30 moAbs, among others to the forefront of lymphoma therapy.

Ibrutinib: a paradigm shift in management of CLL

B-cell receptor (BCR) signaling plays a vital role in B-cell malignancies; Bruton tyrosine kinase is a critical mediator of this signaling. BCR signaling, either constitutively or following antigen binding, leads to activation of several downstream pathways involved in cell survival, proliferation and migration. The efficacy observed in studies of the Bruton tyrosine kinase inhibitor, ibrutinib, confirms that BCR signaling is critical for the growth of B-cell malignancies. Ibrutinib characteristically induces redistribution of malignant B cells from tissues into the peripheral blood and rapid resolution of adenopathy. Furthermore, ibrutinib therapy results in normalization of lymphocyte counts and improvement in cytopenias. Ibrutinib has been shown to have an excellent safety profile and does not cause myelosuppression. Early data from combination studies of ibrutinib with anti-CD20 monoclonal antibodies have shown more rapid responses compared to those seen with ibrutinib monotherapy. Current data strongly support continued clinical evaluation of ibrutinib in B-cell malignancies.

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.

Ofatumumab in poor-prognosis chronic lymphocytic leukemia: a phase IV, non-interventional, observational study from the European Research Initiative on Chronic Lymphocytic Leukemia

We report the largest retrospective, phase IV non-interventional, observational study of ofatumumab therapy in heavily pre-treated patients with poor-prognosis chronic lymphocytic leukemia. Total number of patients was 103; median age was 65 years (range 39-85). Median number of prior lines of therapy was 4 (range 1-13), including, in most cases, rituximab-, fludarabine- and alemtuzumab-based regimens; 13 patients had been allografted. Of 113 adverse events, 28 (29%) were considered to be directly related to ofatumumab. Grade 3-4 toxicities included neutropenia (10%), thrombocytopenia (5%), anemia (3%), pneumonia (17%), and fever (3%). Two heavily pre-treated patients developed progressive multifocal leukoencephalopathy. On an intention-to-treat analysis, the overall response rate was 22% (3 complete response, 1 incomplete complete response). Median progression-free and overall survival times were 5 and 11 months, respectively. This study confirms in a daily-life setting the feasibility and acceptable toxicity of ofatumumab treatment in advanced chronic lymphocytic leukemia. The complete response rate, however, was low. Therefore, treatment with ofatumumab should be moved to earlier phases of the disease. Ideally, this should be done in combination with other agents, as recently approved for ofatumumab plus chlorambucil as front-line treatment for patients unfit for fludarabine. This study is registered at clinicaltrials.gov identifier:01453062.

Transplantation in chronic lymphocytic leukemia: does it still matter in the era of novel targeted therapies?

Allogeneic stem cell transplantation (HSCT) offers the only potentially curative approach in chronic lymphocytic leukemia (CLL). However, this applies only to a minority of patients, and is associated with significant treatment-related mortality and morbidity. HSCT must therefore always be considered in view of other, potentially less toxic therapies. Several new agents demonstrate impressive and durable responses in high-risk patients who might be candidates for HSCT. Therefore the choice of HSCT versus a novel agent is one that must be gauged on a patient-by-patient basis; this will change as data mature on the use of these novel agents in CLL.

New antibody approaches to lymphoma therapy

The CD20-directed monoclonal antibody rituximab established a new era in lymphoma therapy. Since then other epitopes on the lymphoma surface have been identified as potential targets for monoclonal antibodies (mAb). While most mAbs eliminate lymphoma cells mainly by antibody-dependent cellular cytotoxicity, complement-dependent cytotoxicity or direct cell death, others counter mechanisms utilized by malignant cells to evade immune surveillance. Expression of PD-L1 on malignant or stromal cells in the tumor environment for example leads to T-cell anergy. Targeting either PD-1 or PD-L1 via mAbs can indirectly eliminate cancer cells by unblocking the host intrinsic immune response. Yet another mechanism of targeted therapy with mAbs are bi-specific T-cell engagers (BiTE) such as blinatumomab, which directly engages the host immune cells. These examples highlight the broad spectrum of available therapies targeting the lymphoma surface with mAbs utilizing both passive and active immune pathways. Many of these agents have already demonstrated significant activity in clinical trials. In this review we will focus on novel CD20-directed antibodies as well as mAbs directed against newer targets like CD19, CD22, CD40, CD52 and CCR4. In addition we will review mAbs unblocking immune checkpoints and the BiTE blinatumomab. Given the success of mAbs and the expansion in active and passive immunotherapies, these agents will play an increasing role in the treatment of lymphomas.

Ofatumumab and bendamustine in previously treated chronic lymphocytic leukemia and small lymphocytic lymphoma

Despite initial responses > 90% with fludarabine and rituximab-based regimens, patients with chronic lymphocytic leukemia (CLL) invariably relapse and require further treatment. Ofatumumab and bendamustine have each shown efficacy in relapsed/refractory CLL with overall response rates (ORRs) of 58% and 76%, respectively. Given excellent data with bendamustine and rituximab in relapsed/refractory CLL/small lymphocytic lymphoma (SLL), this phase II study evaluated the combination of ofatumumab and bendamustine in previously treated patients. Patients received ofatumumab 300 mg intravenously (IV) day - 7, followed by ofatumumab 1000 mg IV day 1 and bendamustine 70 mg/m(2) days 1 and 2 of each 28-day cycle. Patients received 4-6 cycles depending on number of prior therapies, as long as well-tolerated or until progression. Of 10 patients enrolled, the ORR was 40% and complete response rate was 20%. The median progression-free and overall survivals were 8.1 months and 16.2 months. Three patients developed Richter transformation. The study was closed early due to unexpected adverse events including infusion-related reactions, infection and neurotoxicity.

Advances in treating chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most prevalent type of leukemia, affects mostly elderly CLL patients, and is incurable without allogeneic transplantation. Although classic chemo(immuno)therapy is still the standard of care for patients in need of treatment, this paradigm might change in the near future with the advent of new therapeutic agents targeting major pathogenic pathways in CLL.

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.

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.

Management of chronic lymphocytic leukemia

In the last decade, the management of chronic lymphocytic leukemia has undergone profound changes that have been driven by an improved understanding of the biology of the disease and the approval of several new drugs. Moreover, many novel drugs are currently under evaluation for rapid approval or have been approved by regulatory agencies, further broadening the available therapeutic armamentarium for patients with chronic lymphocytic leukemia. The use of novel biological and genetic parameters combined with a careful clinical evaluation allows us to dissect some of the heterogeneity of the disease and to distinguish patients with a very mild onset and course, who often will not need any treatment, from those with an intermediate prognosis and a third group with a very aggressive course (high-risk leukemia). On this background, it becomes increasingly challenging to select the right treatment strategy. In this paper, we describe our own approach to the management of different patients with chronic lymphocytic leukemia.