Bendamustine in combination with Ofatumumab in relapsed or refractory chronic lymphocytic leukemia: a GIMEMA Multicenter Phase II Trial

Immune-inflammatory modulation by natural products derived from edible and medicinal herbs used in Chinese classical prescriptions

BACKGROUND

Edible and medicinal herbs1 (EMHs) refer to a class of substances with dual attribution of food and medicine. These substances are traditionally used as food and also listed in many international pharmacopoeias, including the European Pharmacopoeia, the United States Pharmacopoeia, and the Chinese Pharmacopoeia. Some classical formulas that are widely used in traditional Chinese medicine include a series of EMHs, which have been shown to be effective with obvious characteristics and advantages. Notably, these EMHs and Chinese classical prescriptions2 (CCPs) have also attracted attention in international herbal medicine research because of their low toxicity and high efficiency as well as the rich body of experience for their long-term clinical use.

PURPOSE

Our purpose is to explore the potential therapeutic effect of EMHs with immune-inflammatory modulation for the study of modern cancer drugs.

STUDY DESIGN

In the present study, we present a detailed account of some EMHs used in CCPs that have shown considerable research potential in studies exploring modern drugs with immune-inflammatory modulation.

METHODS

Approximately 500 publications in the past 30 years were collected from PubMed, Web of Science and ScienceDirect using the keywords, such as natural products, edible and medicinal herbs, Chinese medicine, classical prescription, immune-inflammatory, tumor microenvironment and some related synonyms. The active ingredients instead of herbal extracts or botanical mixtures were focused on and the research conducted over the past decade were discussed emphatically and analyzed comprehensively.

RESULTS

More than ten natural products derived from EMHs used in CCPs are discussed and their immune-inflammatory modulation activities, including enhancing antitumor immunity, regulating inflammatory signaling pathways, lowering the proportion of immunosuppressive cells, inhibiting the secretion of proinflammatory cytokines, immunosuppressive factors, and inflammatory mediators, are summarized.

CONCLUSION

Our findings demonstrate the immune-inflammatory modulating role of those EMHs used in CCPs and provide new ideas for cancer treatment in clinical settings.

Taking the Next Step in Double Refractory Disease: Current and Future Treatment Strategies for Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is a monoclonal B-cell lymphoproliferative disease with a high annual incidence in Western countries. As B-cell receptor (BCR) signaling and intrinsic apoptotic resistance play critical roles in the development and survival of CLL cells, therapeutic approaches targeting these pathways have been extensively investigated to tackle this incurable disease. Over the last decade, several Phase 3 trials have confirmed the superior efficacy of covalent Bruton tyrosine kinase inhibitors (cBTKis) and venetoclax, a selective B-cell lymphoma 2 (BCL2) inhibitor, over chemoimmunotherapy. This has been demonstrated in both the treatment-naïve and relapsed/refractory (RR) settings and includes patients with high-risk molecular features. However, these drugs are not curative, with patients continuing to relapse after treatment with both cBTKis and BCL2is, and the optimal treatment strategy for these patients has not been defined. Several novel agents with distinct mechanisms have recently been developed for CLL which have demonstrated efficacy in patients who have previously received cBTKis and BCL2i. In particular, novel BCR-signaling targeting agents have shown promising efficacy in early-phase clinical trials for RR-CLL. Furthermore, cancer immunotherapies such as bispecific antibodies and chimeric antigen receptor T-cells have also shown anti-tumor activity in patients with heavily pretreated RR-CLL. Personalised approaches with these novel agents and combination strategies based on the understanding of resistance mechanisms have the potential to overcome the clinical challenge of what to do next for a patient who has already had a cBTKi and venetoclax.

Immunotherapeutic Strategies in Chronic Lymphocytic Leukemia: Advances and Challenges

Immune-based therapeutic strategies have drastically changed the landscape of hematological disorders, as they have introduced the concept of boosting immune responses against tumor cells. Anti-CD20 monoclonal antibodies have been the first form of immunotherapy successfully applied in the treatment of CLL, in the context of chemoimmunotherapy regimens. Since then, several immunotherapeutic approaches have been studied in CLL settings, with the aim of exploiting or eliciting anti-tumor immune responses against leukemia cells. Unfortunately, despite initial promising data, results from pilot clinical studies have not shown optimal results in terms of disease control - especially when immunotherapy was used individually - largely due to CLL-related immune dysfunctions hampering the achievement of effective anti-tumor responses. The growing understanding of the complex interactions between immune cells and the tumor cells has paved the way for the development of new combined approaches that rely on the synergism between novel agents and immunotherapy. In this review, we provide an overview of the most successful and promising immunotherapeutic modalities in CLL, including both antibody-based therapy (i.e. monoclonal antibodies, bispecific antibodies, bi- or tri- specific killer engagers) and adoptive cellular therapy (i.e. CAR T cells and NK cells). We also provide examples of successful new combination strategies and some insights on future perspectives.

Immune Dysfunctions and Immune-Based Therapeutic Interventions in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is a B-cell malignancy characterized by a wide range of tumor-induced alterations, which affect both the innate and adaptive arms of the immune response, and accumulate during disease progression. In recent years, the development of targeted therapies, such as the B-cell receptor signaling inhibitors and the Bcl-2 protein inhibitor venetoclax, has dramatically changed the treatment landscape of CLL. Despite their remarkable anti-tumor activity, targeted agents have some limitations, which include the development of drug resistance mechanisms and the inferior efficacy observed in high-risk patients. Therefore, additional treatments are necessary to obtain deeper responses and overcome drug resistance. Allogeneic hematopoietic stem cell transplantation (HSCT), which exploits immune-mediated graft-versus-leukemia effect to eradicate tumor cells, currently represents the only potentially curative therapeutic option for CLL patients. However, due to its potential toxicities, HSCT can be offered only to a restricted number of younger and fit patients. The growing understanding of the complex interplay between tumor cells and the immune system, which is responsible for immune escape mechanisms and tumor progression, has paved the way for the development of novel immune-based strategies. Despite promising preclinical observations, results from pilot clinical studies exploring the safety and efficacy of novel immune-based therapies have been sometimes suboptimal in terms of long-term tumor control. Therefore, further advances to improve their efficacy are needed. In this context, possible approaches include an earlier timing of immunotherapy within the treatment sequencing, as well as the possibility to improve the efficacy of immunotherapeutic agents by administering them in combination with other anti-tumor drugs. In this review, we will provide a comprehensive overview of main immune defects affecting patients with CLL, also describing the complex networks leading to immune evasion and tumor progression. From the therapeutic standpoint, we will go through the evolution of immune-based therapeutic approaches over time, including i) agents with broad immunomodulatory effects, such as immunomodulatory drugs, ii) currently approved and next-generation monoclonal antibodies, and iii) immunotherapeutic strategies aiming at activating or administering immune effector cells specifically targeting leukemic cells (e.g. bi-or tri-specific antibodies, tumor vaccines, chimeric antigen receptor T cells, and checkpoint inhibitors).

Survival improvement of patients with chronic lymphocytic leukemia (CLL) in routine care 1995-2017

Seven hundred and twenty-four CLL-outpatients with a median age of 67 (35-92) were analyzed. Four hundred and twenty-seven (59%) were male, 297 (41%) female. At diagnosis 556 (77%) were in Binet stage A, 91 (13%) stage B and 36 (5%) stage C. Forty-six percent received treatment during the evaluation period. Treatment consisted of purine analogs in 38%, alkylating agents in 96%, chemoimmunotherapy with anti-CD20 monoclonal antibodies in 63%, ibrutinib in 9%, venetoclax in 1% and idelalisib in 3%. 3% received allogeneic hematopoietic stem cell transplantation. Overall survival (OS) according to Binet stage was: A 13.9 years (0.1-37.4), B 9.2 years (1.4-29.3) and C 7.9 years (0.5-19.4) respectively. Median OS from the start of therapy improved over time; 1995-2001: 5.8 years, 2002-2008: 6.1 years and 2009-2017: median not reached. Survival of patients with CLL has improved in routine care and was strongly related to active disease, disease stage, performance status and whether therapy included an anti-CD20 monoclonal antibody.

[Chronic lymphocytic leukemia]

Chronic lymphocytic leukemia is the most frequent adult leukemia. Eighty per cent of the patients are asymptomatic at diagnosis and 30% of the patients will be never treated. The diagnosis is based on the blood smear examination and immunophenotyping by flow cytometry of blood lymphocytes. The first line option is immunochemotherapy in 90% of the patients without genetic abnormalities associated with chemo resistance. The use of new compounds targeting different pathways is more frequent especially in relapsing patients and could be an alternative to the chemotherapy in the future. Asymptomatic patients with a stable disease assessed by the specialist can be followed by the general practitioner with a blood count and clinical examination every six months or once a year.

Nitrogen Mustards as Anticancer Chemotherapies: Historic Perspective, Current Developments and Future Trends

Nitrogen mustards, a family of DNA alkylating agents, marked the start of cancer pharmacotherapy. While traditionally characterized by their dose-limiting toxic effects, nitrogen mustards have been the subject of intense research efforts, which have led to safer and more effective agents. Even though the alkylating prodrug mustards were first developed decades ago, active research on ways to improve their selectivity and cytotoxic efficacy is a currently active topic of research. This review addresses the historical development of the nitrogen mustards, outlining their mechanism of action, and discussing the improvements on their therapeutic profile made through rational structure modifications. A special emphasis is made on discussing the nitrogen mustard prodrug category, with Cyclophosphamide (CPA) serving as the main highlight. Selected insights on the latest developments on nitrogen mustards are then provided, limiting such information to agents that preserve the original nitrogen mustard mechanism as their primary mode of action. Additionally, future trends that might follow in the quest to optimize these invaluable chemotherapeutic medications are succinctly suggested.

Renal involvement in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most commonly diagnosed adult leukemia in the USA and Western Europe. Kidney disease can present in patients with CLL as a manifestation of the disease process such as acute kidney injury with infiltration or with a paraneoplastic glomerular disease or as a manifestation of extra renal obstruction and tumor lysis syndrome. In the current era of novel targeted therapies, kidney disease can also present as a complication of treatment. Tumor lysis syndrome associated with novel agents such as the B-cell lymphoma 2 inhibitor venetoclax and the monoclonal antibody obinutuzumab are important nephrotoxicities associated with these agents. Here we review the various forms of kidney diseases associated with CLL and its therapies.

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.

BENDAMUSTINE: AN OLD DRUG IN THE NEW ERA FOR PATIENTS WITH NON-HODGKIN LYMPHOMAS AND CHRONIC LYMPHOCYTIC LEUKEMIA

- The aim of this review is to present data on bendamustine, a non-cross resistant alkylating agent, alone or in combination for treatment of non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL). Bendamustine is currently approved for rituximab-resistant indolent NHL and CLL in patients not fit for conventional chemotherapy. Recent studies have shown superiority of bendamustine combination with rituximab (B-R) in first line treatment of indolent NHLs and mantle cell lymphoma, suggesting a shift of the standard of care in this setting. B-R regimen has also shown efficacy in relapsed setting suggesting the possible treatment option for patients failing conventional chemotherapy. In rituximab-resistant NHL, the recent GADOLIN study exploring the addition of obinutuzumab to bendamustine has yielded impressive result changing the standard of care in this hard-to-treat population. Concerning CLL, despite inferiority to the standard of care in young fit patients, as defined in CLL10 study, B-R has yielded a more beneficial toxicity profile and its use in first line treatment should be decided individually. In relapsed setting, the addition of ibrutinib to B-R has shown superior results compared to B-R alone, possibly changing the paradigm of treatment of relapsed CLL. In conclusion, bendamustine as a single agent or in combinations has shown activity with acceptable toxic profile in the treatment of patients with indolent NHLs or CLL without del(17p) mutation.

Efficacy of bendamustine and rituximab as first salvage treatment in chronic lymphocytic leukemia and indirect comparison with ibrutinib: a GIMEMA, ERIC and UK CLL FORUM study

We performed an observational study on the efficacy of ben-damustine and rituximab (BR) as first salvage regimen in chronic lymphocytic leukemia (CLL). In an intention-to-treat analysis including 237 patients, the median progression-free survival (PFS) was 25 months. The presence of del(17p), unmutated IGHV and advanced stage were associated with a shorter PFS at multivariate analysis. The median time-to-next treatment was 31.3 months. Front-line treatment with a chemoimmunotherapy regimen was the only predictive factor for a shorter time to next treatment at multivariate analysis. The median overall survival (OS) was 74.5 months. Advanced disease stage (i.e. Rai stage III-IV or Binet stage C) and resistant disease were the only parameters significantly associated with a shorter OS. Grade 3-5 infections were recorded in 6.3% of patients. A matched-adjusted indirect comparison with ibrutinib given second-line within Named Patient Programs in the United Kingdom and in Italy was carried out with OS as objective end point. When restricting the analysis to patients with intact 17p who had received chemoimmunotherapy in first line, there was no difference in OS between patients treated with ibrutinib (63% alive at 36 months) and patients treated with BR (74.4% alive at 36 months). BR is an efficacious first salvage regimen in CLL in a real-life population, including the elderly and unfit patients. BR and ibrutinib may be equally effective in terms of OS when used as first salvage treatment in patients without 17p deletion.

Obinutuzumab activates FcγRI more potently than other anti-CD20 antibodies in chronic lymphocytic leukemia (CLL)

Treatment with monoclonal antibodies has revolutionized clinical medicine, especially in the fields of cancer and immunology. One of the oldest antibodies, which is widely used for the treatment of lymphomas and autoimmune diseases, is the anti-CD20 antibody rituximab. In recent years, new antibodies against CD20 have been developed including ofatumumab and obinutuzumab. An important mechanism of action of therapeutic monoclonal antibodies is activation of immune cells via Fc receptors (FcγRs). However, surprisingly, little is known about triggering of FcγRs by different therapeutic antibodies in general and anti-CD20 antibodies in particular. Here we establish a reporter assay to assess whether a particular antibody activates a certain Fc receptor. Using this assay we corroborated previous reports demonstrating obinutuzumab's ability to highly activate FcγRIIIa (CD16a). Importantly, we discovered that obinutuzumab also activates FcγRI (CD64) significantly more than rituximab and ofatumumab in response to chronic lymphocytic leukemia (CLL) cells obtained from patients. Mechanistically we show that this is due to the lack of FcγRIIb-mediated internalization of obinutuzumab following binding to CD20. Moreover, we show that obinutuzumab induces increased phagocytosis by primary macrophages in an FcγRI-dependent manner. Beyond the discovery of a new mechanism of obinutuzumab activity, the reporter assay can be applied to other therapeutic antibodies and may assist in developing antibodies with improved immunological properties.

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.

Tumor Lysis Syndrome in Chronic Lymphocytic Leukemia with Novel Targeted Agents

Tumor lysis syndrome (TLS) is an uncommon but potentially life-threatening complication associated with the treatment of some cancers. If left untreated, TLS may result in acute renal failure, cardiac dysrhythmia, neurologic complications, seizures, or death. Tumor lysis syndrome is most commonly observed in patients with hematologic malignancies with a high proliferation rate undergoing treatment with very effective therapies. In chronic lymphocytic leukemia (CLL), historically, TLS has been observed less often, owing to a low proliferation rate and slow response to chemotherapy. New targeted therapies have recently been approved in the treatment of CLL, including the oral kinase inhibitors, idelalisib and ibrutinib, and the B-cell lymphoma-2 protein inhibitor, venetoclax. Several others are also under development, and combination strategies of these agents are being explored. This review examines the diagnosis, prevention, and management of TLS and summarizes the TLS experience in CLL clinical trials with newer targeted agents. Overall, the risk of TLS is small, but the consequences may be fatal; therefore, patients should be monitored carefully. Therapies capable of eliciting rapid response and combination regimens are increasingly being evaluated for treatment of CLL, which may pose a higher risk of TLS. For optimal management, patients at risk for TLS require prophylaxis and close monitoring with appropriate tests and appropriate management to correct laboratory abnormalities, which allows for safe and effective disease control.

IMPLICATIONS FOR PRACTICE

Tumor lysis syndrome (TLS) is a potentially fatal condition observed with hematologic malignancies, caused by release of cellular components in the bloodstream from rapidly dying tumor cells. The frequency and severity of TLS is partly dependent upon the biology of the disease and type of therapy administered. Novel targeted agents highly effective at inducing rapid cell death in chronic lymphocytic leukemia (CLL) may pose a risk for TLS in patients with tumors characterized by rapid growth, high tumor burden, and/or high sensitivity to treatment. In this review, prevention strategies and management of patients with CLL who develop TLS are described.

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.

Pharmacotherapy of relapsed/refractory chronic lymphocytic leukemia

INTRODUCTION

The treatment of relapsed/refractory (RR) CLL has been revolutionized by the advent of the new oral inhibitors of B-cell receptor (BCR) signaling and the pro-survival protein, B-cell lymphoma 2 (BCL2). Additionally, new and more potent monoclonal antibodies against CD20 have replaced/may replace rituximab in many settings. Areas covered: Herein, we review the entire therapeutic landscape of RR CLL, with particular attention to the new small-molecule kinase inhibitors and BH3-mimetics. We discuss preclinical data with these agents in CLL, cover available efficacy and safety information, and examine potential resistance mechanisms and possible rational combinations to circumvent them. Expert opinion: The availability of potent and selective inhibitors of BCR signaling and of the anti-apoptotic functions of BCL2 has enormously enhanced our therapeutic armamentarium, with unprecedented efficacy now observed in patients who historically had poor outcomes with chemoimmunotherapy (CIT), e.g., those with deletion 17p/11q and/or IGHV-unmutated disease. The next challenge is to optimally sequence these agents and develop rational combinations that will hopefully lead to deeper and more durable remissions than ever seen before. Indeed, long term relapse free survival, already achievable with CIT in patients with genetically favorable-risk disease, now appears to be a realistic possibility for most patients with CLL.

Bendamustine and its role in the treatment of unfit patients with chronic lymphocytic leukaemia: a perspective review

With a median age of 72 years at first diagnosis, chronic lymphocytic leukaemia (CLL) is a disease of the elderly. At this age, many patients cannot bear an intensive chemoimmunotherapy like fludarabine, cyclophosphamide and rituximab (FCR), and therapeutic decisions are commonly complicated by a high burden of accompanying comorbidities. Clinical trials, on the other hand, are mostly designed to include a far healthier and younger trial population, with a median age in most studies well below 70 years, leading to an insufficient reflection of clinical reality. With the introduction of new targeted therapies, treatment of CLL is currently undergoing a profound change. New compounds like ibrutinib or idelalisib have enlarged the therapeutic options in treating CLL. However, so far, these oral medications imply continuous intake by the patient, which will at some point lead to the issue of adherence in most patients. In addition, long-term experiences are largely missing. In this setting, one of the oldest chemoactive substances remains a viable option for many CLL patients and their treating physicians: bendamustine, a nitrogen-mustard derivative, has proven to be a safe and efficient agent for treatment of CLL in the first- and second-line setting. In particular, there is some evidence that the substance is relatively well tolerated in elderly and unfit patients. In this review, we summarize the current data on bendamustine in the treatment of elderly and unfit patients with CLL and aim to provide a concise analysis and outlook on the current and future role of this substance in the era of new targeted agents.

Venetoclax in Patients with Previously Treated Chronic Lymphocytic Leukemia

Venetoclax is the first BCL2 inhibitor to enter routine clinical practice. It is an orally bioavailable small molecule that binds BCL2 very specifically. Acting as a pharmacologic mimic of the proteins that initiate apoptosis (a so-called BH3 mimetic), venetoclax rapidly induces apoptosis in chronic lymphocytic leukemia (CLL) cells, which express high levels of BCL2 and rely on it to maintain their survival. As a single agent, daily venetoclax treatment induced durable responses in 79% of patients with relapsed or refractory CLL or small lymphocytic lymphoma in a phase I study, including complete remissions in 20% of patients. Its use was approved by the FDA in April 2016 for patients with previously treated del(17p) CLL on the basis of a single-arm phase II trial demonstrating a 79% response rate and an estimated 1-year progression-free survival of 72% with 400 mg/day continuous therapy. This review focuses on venetoclax, its mechanism of action, pharmacology, and clinical trial data and seeks to place it in the context of rapid advances in therapy for patients with relapsed CLL, especially those with del(17p) CLL. Clin Cancer Res; 23(16); 4527-33. ©2017 AACR.

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.

Chemotherapy plus Ofatumumab at Standard or Mega dose in relapsed CLL (COSMIC) trial: study protocol for a phase II randomised controlled trial

Background

Chronic lymphocytic leukaemia (CLL) is the most common adult leukaemia. Combination immunochemotherapy such as fludarabine, cyclophosphamide and rituximab is the standard first line therapy in fit patients, but there is limited evidence regarding the optimal treatment of patients after relapse. Ofatumumab as monotherapy has been proven to be effective in the treatment of relapsed, refractory CLL, and as it is not myelotoxic, it is an ideal drug to combine with chemotherapy. However, the optimal dose of ofatumumab in this setting is not known. The Chemotherapy plus Ofatumumab at Standard or Mega dose in relapsed CLL (COSMIC) trial will assess the efficacy and safety of standard and high (mega) doses of ofatumumab combined with bendamustine or a combination of fludarabine and cyclophosphamide to determine which, if either, schedule should progress to a phase III trial.

Methods/design

COSMIC is a phase II, multi-centre, randomised, open, parallel group trial for patients with relapsed CLL who are not refractory to fludarabine-based chemotherapy. Participants will be randomised to receive either standard dose or mega dose ofatumumab. Both doses will be given in combination with either bendamustine or fludarabine and cyclophosphamide chemotherapy backbone. The primary objective is to assess the proportion of participants achieving a complete remission following therapy with the two treatment arms (mega versus standard), as assessed at 3 months post treatment. The treatment groups will be assessed independently to determine whether the level of response is acceptable in relation to pre-specified criteria. If both treatment groups show an acceptable level of response, selection criteria will be used to determine which to take forward to a confirmatory phase III trial. A key secondary objective is to assess the dynamics of minimal residual disease (MRD) levels in relapsed disease. Eighty-two participants are planned to be recruited from 18 research centres in the UK.

Discussion

Currently there is limited evidence regarding the optimal treatment of patients with relapsed or refractory CLL, and so suitable therapies are urgently needed. The COSMIC trial will identify whether ofatumumab given in combination with chemotherapy is safe and effective in this population, and will identify the optimal doses for further investigation.

Trial registration

ISRCTN51382468. Registered on 21 September 2011.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1581-0) contains supplementary material, which is available to authorized users.

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.

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.

Optimal use of bendamustine in hematologic disorders: Treatment recommendations from an international consensus panel - an update

Bendamustine has achieved widespread international regulatory approval and is a standard agent for the treatment for chronic lymphocytic leukemia (CLL), indolent non-Hodgkin lymphoma and multiple myeloma. Since approval, the number of indications for bendamustine has expanded to include aggressive non-Hodgkin lymphoma and Hodgkin lymphoma and novel targeted therapies, based on new bendamustine regimens/combinations, are being developed against CLL and lymphomas. In 2010, an international panel of bendamustine experts met and published a set of recommendations on the safe and effective use of bendamustine in patients suffering from hematologic disorders. In 2014, this panel met again to update these recommendations since the clarification of issues including optimal dosing and management of bendamustine-related toxicities. The aim of this report is to communicate the latest consensus on the use of bendamustine, permitting the expansion of its safe and effective administration, particularly in new combination therapies.

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.

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.

Recommendations on the clinical use of bendamustine in lymphoproliferative syndromes and multiple myeloma

Bendamustine is an increasingly used hybrid alkylating agent that is active in lymphoid neoplasias via a novel mechanism of action. There are some pending questions about its use in clinical practice because of its developmental features. A consensus panel of several leading Spanish hematologists with broad experience in the clinical use of bendamustine has established recommendations for the management and treatment of hematological patients with bendamustine based on available clinical data and the experience of the participants. These recommendations address the dose and treatment regimen for different clinical indications, the management of toxicity, and support therapy. This article contains the conclusions of this consensus panel, which are intended to serve as guidelines for the use of bendamustine.

Safety and activity of BTK inhibitor ibrutinib combined with ofatumumab in chronic lymphocytic leukemia: a phase 1b/2 study

Ibrutinib represents a therapeutic advance in chronic lymphocytic leukemia (CLL) but as monotherapy produces few complete remissions in previously treated patients. Anti-CD20 antibodies have improved response and progression-free survival (PFS) when combined with chemotherapy. We evaluated the safety and activity of adding ofatumumab to ibrutinib in 3 different administration sequences. Patients with CLL/small lymphocytic lymphoma (SLL), prolymphocytic leukemia, or Richter's transformation who failed ≥2 prior therapies were enrolled. Patients received ibrutinib 420 mg daily and 12 doses of ofatumumab 300/2000 mg in 3 schedules: ibrutinib lead-in (group 1; n = 27), concurrent start (group 2; n = 20), or ofatumumab lead-in (group 3; n = 24). Seventy-one patients were treated; most had high-risk disease including del(17)(p13.1) (44%) or del(11)(q22.3) (31%). The most frequent adverse events (any grade) were diarrhea (70%), infusion-related reaction (45%), and peripheral sensory neuropathy (44%). Overall response rates in CLL/SLL patients (n = 66) were 100%, 79%, and 71% in groups 1, 2, and 3, respectively. Estimated 12-month PFSs for all patients were 89%, 85%, and 75%, respectively. Four patients in group 3 progressed prior to receiving ibrutinib. This study demonstrates the tolerability and clinical activity of this combination with quicker time to best response than single-agent ibrutinib and with durable responses. This trial was registered at www.clinicaltrials.gov as #NCT01217749.

Salvage outcomes in patients with first relapse after fludarabine, cyclophosphamide, and rituximab for chronic lymphocytic leukemia: the French intergroup experience

The optimal management of patients with relapsed chronic lymphocytic leukemia (CLL) is dictated by the type of prior therapy, duration of prior response, presence of genomic aberrations, age, and comorbidities. The patterns of relapses and the clinical outcomes of second-line options after fludarabine-cyclophosphamide-rituximab (FCR) is given as a frontline treatment are currently unknown. In this retrospective and non-randomized study, we report the outcomes of 132 patients from databases of 14 French CLL study group centers who needed a second-line treatment after FCR frontline. Bendamustine + rituximab (BR) was the most frequently used second-line regimen, followed by alemtuzumab-based regimens, R-CHOP, and FCR. Median progression-free survival (PFS) was 18 months after BR with a median overall survival (OS) not reached. We also found that response durations of < 36 months and the presence of del(17p) are critical factors that contribute to poor overall survival. BR appears to be an effective salvage regimen in our series, both in terms of progression-free and overall survival. Patients who relapsed less than 36 months after FCR have a poor outcome, not significantly different in this study from patients with early relapses less than 12 or 24 months.

Ofatumumab added to dexamethasone in patients with relapsed or refractory chronic lymphocytic leukemia: Results from a phase II study

The treatment of relapsed/refractory chronic lymphocytic leukemia (CLL) remains a challenging clinical issue. An important treatment option is the use of high-dose corticosteroids. The purpose of this clinical trial was to determine the efficacy and toxicity of an ofatumumab-dexamethasone (O-Dex) combination in relapsed or refractory CLL. The trial was an open-label, multicenter, nonrandomized, Phase II study. The O-Dex regimen consisted of intravenous ofatumumab (Cycle 1: 300 mg on day 1, 2,000 mg on days 8, 15, and 22; Cycles 2-6: 1,000 mg on days 1, 8, 15, and 22) and oral dexamethasone (40 mg on days 1-4 and 15-18; Cycles 1-6). The O-Dex regimen was given until best response, or a maximum of six cycles. Thirty-three patients (pts) were recruited. Twenty-four (73%) pts completed at least three cycles of therapy. The remaining nine pts were prematurely discontinued owing to Grade 3/4 infections (seven pts), disease progression (one pt), or uncontrollable diabetes mellitus (one pt). Overall response rates/complete remissions (ORR/CR) were achieved in 22/5 pts (67/15%). The median progression-free survival (PFS) was 10 months. In pts with p53 defects (n = 8), ORR/CR were achieved in 5/2 pts (63/25%) with a median PFS of 10.5 months. The median overall survival (OS) was 34 months. The Grades 3-5 infectious toxicity in 33% of pts represented the most frequent side effect during the treatment period. In conclusion, the O-Dex regimen shows a relatively high ORR and CR with promising findings for PFS and OS. The study was registered at www.clinicaltrials.gov (NCT01310101).

The efficacy and safety of rituximab in treating childhood refractory nephrotic syndrome: a meta-analysis

Rituximab is considered to be a promising drug for treating childhood refractory nephrotic syndrome. However, the efficacy and safety of rituximab in treating childhood refractory nephrotic syndrome remain inconclusive. This meta-analysis aimed to investigate the efficacy and safety of rituximab treatment compared with other immunosuppressive agents in children with refractory nephrotic syndrome. Three randomized controlled trials and two comparative control studies were included in our analysis. The included studies were of moderately high quality. Compared with other immunotherapies, rituximab therapy significantly improved relapse-free survival (hazard ratio = 0.49, 95% confidence interval [CI], 0.26–0.92, P = 0.03). Rituximab also achieved a higher rate of complete remission (risk ratio,1.62; 95% CI, 0.92 to 2.84, P = 0.09) and reduced the occurrence of proteinuria (mean difference = −0.25, 95% CI = −0.29 to −0.21, P < 0.00001); however, a more targeted rituximab treatment did not significantly increase serum albumin levels and did not significantly reduce adverse events. Rituximab might be a promising treatment for childhood refractory nephrotic syndrome; however, the long-term effects and cost-effectiveness of rituximab treatment were not fully assessed, and there were limited studies that evaluated the clinical benefits of a concurrent infusion of rituximab plus a steroid compared with an infusion of rituximab only. Additional studies are required to address these issues.

Human organic cation transporter 1 (hOCT1) as a mediator of bendamustine uptake and cytotoxicity in chronic lymphocytic leukemia (CLL) cells

Bendamustine is used in the treatment of chronic lymphocytic leukemia (CLL). Routes for bendamustine entry into target cells are unknown. This study aimed at identifying transporter proteins implicated in bendamustine uptake. Our results showed that hOCT1 is a bendamustine transporter, as bendamustine could cis-inhibit the uptake of a canonical hOCT1 substrate, with a Ki in the micromolar range, consistent with the EC50 values of the cytotoxicity triggered by this drug in HEK293 cells expressing hOCT1. hOCT1 polymorphic variants determining impaired bendamustine-transporter interaction, consistently reduced bendamustine cytotoxicity in HEK293 cells stably expressing them. Exome genotyping of the SLC22A1 gene, encoding hOCT1, was undertaken in a cohort of 241 CLL patients. Ex vivo cytotoxicity to bendamustine was measured in a subset of cases and shown to correlate with SLC22A1 polymorphic variants. In conclusion, hOCT1 is a suitable bendamustine transporter, thereby contributing to its cytotoxic effect depending upon the hOCT1 genetic variants expressed.

Clinical study of the novel cyclin-dependent kinase inhibitor dinaciclib in combination with rituximab in relapsed/refractory chronic lymphocytic leukemia patients

PURPOSE

Dinaciclib is a novel selective inhibitor of cyclin-dependent kinase (CDK)1, CDK2, CDK5, and CDK9. We conducted a phase I study to investigate the effects of dinaciclib when administered with rituximab.

METHODS

In this phase I nonrandomized dose-escalation 3 + 3 trial, patients with relapsed/refractory chronic lymphocytic leukemia (CLL) were treated with dinaciclib and rituximab. Dinaciclib was administered intravenously (IV) over 2 h on days 1, 8 and 15 in cycles 2-13 (28-day cycles). Rituximab 375 mg/m(2) was administered IV on days 1, 8, 15 and 22 in cycle 1 (28-day cycle) and on day 1 during cycle 3-13. Rituximab was not administered in cycle 2. Rituximab and dinaciclib were given alone in cycles 1 and 2, respectively, and in combination in cycles 3-13. Primary objectives included determination of the recommended phase II dose of dinaciclib and evaluation of pharmacokinetics (PK) when administered with rituximab.

RESULTS

Five patients completed the study due to early termination. All presented with drug-related adverse events (AEs), but no dose-limiting toxicities were observed. The most commonly observed toxicities included hematological, digestive and metabolic AEs. However, no tumor lysis syndrome has been reported in the study. Four patients achieved stable disease, and one patient achieved complete response according to 2008 iwCLL criteria at cycle 3. PK samples were collected from 5 patients, and no obvious interaction between dinaciclib and rituximab was observed.

CONCLUSIONS

Limited data from this study shows dinaciclib in combination with rituximab was well tolerated and revealed encouraging clinical activity in relapsed/refractory CLL patients.

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.

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.

Anti-CD20 monoclonal antibodies and associated viral hepatitis in hematological diseases

Over the past decade, the administration of anti-CD20 monoclonal antibodies such as rituximab has demonstrated various degrees of effectiveness and has improved patients’ outcomes during the treatment of autoimmune hematological disorders and hematological malignancies. However, the depletion of B-cells, the distribution of T-cell populations, and the reconstruction of host immunity resulting from the use of anti-CD20 monoclonal antibodies potentially lead to severe viral infections, such as hepatitis B virus (HBV), hepatitis C virus (HCV), parvovirus B19, and herpes viruses, in patients who are undergoing immune therapy or immunochemotherapy. Of these infections, HBV- and HCV-related hepatitis are a great concern in endemic areas because of the high morbidity and mortality rates in untreated patients. As a result, prophylaxis against HBV infection is becoming a standard of care in these areas. Parvovirus B19, a widespread pathogen that causes red blood cell aplasia in immunocompromised hosts, also causes hepatitis in healthy individuals. Recently, its association with hepatitis was recognized in a patient treated with rituximab. In addition, adenovirus, varicella-zoster virus, hepatitis E virus, and rituximab itself have been linked to the occurrence of hepatitis during or after rituximab treatments. The epidemiologies and pathogeneses of these etiologies remain unknown. Because of the increasing use of anti-CD20 monoclonal antibodies for the treatment of hematological malignancies or autoimmune hematological disorders, it is imperative that physicians understand and balance the risks of hepatotropic virus-associated hepatitis against the benefits of using anti-CD20 monoclonal antibodies.