Pentostatin and rituximab therapy for previously untreated patients with B-cell chronic lymphocytic leukemia

Targeted Silencing of NRF2 by rituximab-conjugated nanoparticles increases the sensitivity of chronic lymphoblastic leukemia cells to Cyclophosphamide

BACKGROUND

Targeting influential factors in resistance to chemotherapy is one way to increase the effectiveness of chemotherapeutics. The nuclear factor erythroid 2-related factor 2 (Nrf2) pathway overexpresses in chronic lymphocytic leukemia (CLL) cells and appears to have a significant part in their survival and chemotherapy resistance. Here we produced novel nanoparticles (NPs) specific for CD20-expressing CLL cells with simultaneous anti-Nrf2 and cytotoxic properties.

METHODS

Chitosan lactate (CL) was used to produce the primary NPs which were then respectively loaded with rituximab (RTX), anti-Nrf2 Small interfering RNA (siRNAs) and Cyclophosphamide (CP) to prepare the final version of the NPs (NP-Nrf2_siRNA-CP). All interventions were done on both peripheral blood mononuclear cells (PBMCs) and bone marrow mononuclear cells (BMNCs).

RESULTS

NP-Nrf2_siRNA-CP had satisfying physicochemical properties, showed controlled anti-Nrf2 siRNA/CP release, and were efficiently transfected into CLL primary cells (both PBMCs and BMNCs). NP-Nrf2_siRNA-CP were significantly capable of cell apoptosis induction and proliferation prevention marked by respectively decreased and increased anti-apoptotic and pro-apoptotic factors. Furthermore, use of anti-Nrf2 siRNA was corresponding to elevated sensitivity of CLL cells to CP.

CONCLUSION

Our findings imply that the combination therapy of malignant CLL cells with RTX, CP and anti-Nrf2 siRNA is a novel and efficient therapeutic strategy that was capable of destroying malignant cells. Furthermore, the use of NPs as a multiple drug delivery method showed fulfilling properties; however, the need for further future studies is undeniable. Video Abstract.

Bridging the Divide: An Onco-Nephrologic Approach to the Monoclonal Gammopathies of Renal Significance

The monoclonal gammopathies of renal significance (MGRS) are a group of disorders characterized by monoclonal Ig deposition in the kidney, but are not associated with systemic lymphoma or overt multiple myeloma. The prevailing hypothesis is that the pathogenic paraproteins in MGRS are produced by underlying B cell or plasma cell clones. However, in the MGRS literature, the yield of detecting a clone has been variable, and progression to ESRD is common. Here, we present an "onco-nephrologic" approach to the MGRS disorders by highlighting recent advances in lymphoma and multiple myeloma that can be used in the evaluation and management of these patients.

Pentostatin, cyclophosphamide and rituximab for previously untreated advanced stage, low-grade B-cell lymphomas

We conducted a prospective phase II trial of pentostatin, cyclophosphamide and rituximab as initial therapy for patients with previously untreated advanced stage low-grade or indolent B-cell lymphomas (iNHLs). Of 83 evaluable patients, 91·6% attained an overall response and 86·8% a complete or unconfirmed complete response. The 3-year progression-free survival (PFS) and overall survival rates were 73% and 93%, respectively. The 3-year PFS rate was significantly different for different diagnoses (P = 0·01): 83% [95% confidence interval (CI): 0·72, 0·96] for follicular lymphomas, 73% (95% CI: 0·54, 1·0) for marginal zone lymphomas and 61% (95% CI: 0·46, 0·81) for small lymphocytic lymphomas. The most common adverse events were haematological. Of 509 cycles of chemotherapy administered, grade 3 or 4 neutropenia was reported in 68 cycles (13% of cycles administered) and most frequently occurred during cycles 4-6. This is the first report demonstrating the effectiveness of pentostatin, cyclophosphamide and rituximab in patients with previously untreated iNHLs, including those over 60 years of age.

Rituximab, ofatumumab and other monoclonal anti-CD20 antibodies for chronic lymphocytic leukaemia

BACKGROUND

Chronic lymphocytic leukaemia (CLL) accounts for 25% of all leukaemias and is the most common lymphoid malignancy in western countries. Standard treatments include mono- or polychemotherapies, usually combined with monoclonal antibodies such as rituximab or alemtuzumab. However, the impact of these agents remains unclear, as there are hints for increased risk of severe infections.

OBJECTIVES

The objectives of this review are to provide an evidence-based answer regarding the clinical benefits and harms of monoclonal anti-CD20 antibodies (such as rituximab, ofatumumab, GA101) compared to no further therapy or to other anti-leukaemic therapies in patients with CLL, irrespective of disease status.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 12, 2011), MEDLINE (from January 1990 to 4 January 2012), and EMBASE (from 1990 to 20 March 2009) as well as conference proceedings (American Society of Hematology, American Society of Clinical Oncology, European Hematology Association and European Society of Medical Oncology) for randomised controlled trials (RCTs).

SELECTION CRITERIA

We included RCTs examining monoclonal anti-CD20 antibodies compared to no further therapy or to anti-leukaemic therapy such as chemotherapy or monoclonal antibodies in patients with newly diagnosed or relapsed CLL.

DATA COLLECTION AND ANALYSIS

We used hazard ratios (HR) as effect measures for overall survival (OS), progression-free survival (PFS) and time to next treatment, and risk ratios (RR) for response rates, treatment-related mortality (TRM) and adverse events (AEs). Two review authors independently extracted data and assessed quality of trials.

MAIN RESULTS

We screened a total of 1150 records. Seven RCTs involving 1763 patients were identified, but only five could be included in the two separate meta-analyses we performed. We judged the overall the quality of these trials as moderate to high. All trials were randomised and open-label studies. However, two trials were published as abstracts only, therefore we were unable to assess the potential risk of bias for these trials in detail.Three RCTs (N = 1421) assessed the efficacy of monoclonal anti-CD20 antibodies (i.e. rituximab) plus chemotherapy compared to chemotherapy alone. The meta-analyses showed a statistically significant OS (HR 0.78, 95% confidence interval (CI) 0.62 to 0.98, P = 0.03, the number needed to treat for an additional beneficial effect (NNTB) was 12) and PFS (HR 0.64, 95% CI 0.55 to 0.74, P < 0.00001) advantage for patients receiving rituximab. In the rituximab-arm occurred more AEs, World Health Organization (WHO) grade 3 or 4 (3 trials, N = 1398, RR 1.15, 95% CI 1.08 to 1.23, P < 0.0001; the number needed to harm for an additional harmful outcome (NNTH) was 9), but that did not lead to a statistically significant difference regarding TRM (3 trials, N = 1415, RR 1.19, 95% CI 0.70 to 2.01, P = 0.52).Two trials (N = 177) evaluated rituximab versus alemtuzumab. Neither study reported OS or PFS. There was no statistically significant difference between arms regarding complete response rate (CRR) (RR 1.21, 95% CI 0.94 to 1.58, P = 0.14) or TRM (RR 0.31, 95% CI 0.06 to 1.51, P = 0.15). However, the CLL2007FMP trial was stopped early owing to an increase in mortality in the alemtuzumab arm. More serious AEs occurred in this arm (43% with alemtuzumab versus 22% with rituximab; P = 0.006).Two trials assessed different dosages or time schedules of monoclonal anti-CD20 antibodies. One trial (N = 104) evaluated two different rituximab schedules (concurrent arm: fludarabine plus rituximab (Flu-R) plus rituximab consolidation versus sequential arm: fludarabine alone plus rituximab consolidation). The comparison of the concurrent versus sequential regimen of rituximab showed a statistically significant difference of the CRR with 33% in the concurrent-arm and 15% in the sequential-arm (P = 0.04), that did not lead to statistically significant differences regarding OS (HR 1.14, 95% CI 0.20 to 6.65, P = 0.30) or PFS (HR 0.96, 95% CI 0.43 to 2.15, P = 0.11). Furthermore results showed no differences in occurring AEs, except for neutropenia, which was more often observed in patients of the concurrent arm. The other trial (N = 61) investigated two different dosages (500 mg and 1000 mg) of ofatumumab in addition to FluC. The arm investigating ofatumumab did not assess OS and a median PFS had not been reached owing to the short median follow-up of eight months. It showed no statistically significant differences between arms regarding CRR (32% in the FCO500 arm versus 50% in the FCO1000 arm; P = 0.10) or AEs (anaemia, neutropenia, thrombocytopenia).

AUTHORS' CONCLUSIONS

This meta-analysis showed that patients receiving chemotherapy plus rituximab benefit in terms of OS as well as PFS compared to those with chemotherapy alone. Therefore, it supports the recommendation of rituximab in combination with FluC as an option for the first-line treatment as well as for the people with relapsed or refractory CLL. The available evidence regarding the other assessed comparisons was not sufficient to deduct final conclusions.

Therapeutic advancement of chronic lymphocytic leukemia

Despite the combinations of chemotherapy with monoclonal antibodies have further improved response rates, chronic lymphocytic leukemia (CLL) remains an incurable disease with an extremely variable course. This article reviews the ongoing clinical advances in the treatment of CLL in both previously untreated and relapsed disease and focuses on the benefit of different therapeutic strategies, the most effective therapy combinations and the potential activity of novel agents. Novel agents and combination therapies have been investigated by several studies in both the upfront and relapsed setting, particularly for patients with 17p deletion, TP53 mutation and fludarabine-refractory CLL. While these agents and combination therapies have improved initial response rates, ongoing studies are continued to determine and improve the efficacy and safety. Despite advancements in the treatment of CLL have led to high response rates, allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only curative option and reduced-intensity conditioning (RIC) allo-HSCT must be strongly considered whenever feasible. As such, ongoing studies of these agents and other novel approaches in clinical development are needed to expand and improve treatment options for CLL patients.

Choosing first-line therapy for chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) exhibits a highly variable natural history, but the addition of genomic risk stratification to traditional clinical staging systems has begun to explain the heterogeneous clinical course. Overall response to treatment has significantly improved over the past three decades and for the first time, a survival benefit has been demonstrated with the use of monoclonal antibodies in combination with cytotoxic chemotherapy. Newer therapeutic strategies have abrogated the adverse prognosis associated with some higher risk features, but other genetic subgroups remain at high risk for rapid disease progression and early mortality. Patients at advanced age or with significant comorbidity constitute a large proportion of the CLL population and present unique clinical challenges. This article will discuss the evolution of contemporary therapeutic approaches to the initial treatment of CLL, and highlight the ways in which risk-adapted therapeutic strategies are improving clinical outcomes.

Management of patients with chronic lymphocytic leukemia with a high risk of adverse outcome: the Mayo Clinic approach

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) is usually an incidental diagnosis in patients with early-intermediate stage disease. However, most patients with a diagnosis of CLL will subsequently have significant morbidity and die from their disease and its complications. For these patients, CLL is not the 'good leukemia' with a predictably 'benign' outcome. Indeed, we can now identify a cohort of patients with high-risk CLL at diagnosis who will have rapid disease progression, poor response to treatment, and poor survival based on prognostic methods developed from an improved understanding of the biology of CLL. The concomitant development of improved treatments has led to risk-adjusted management approaches that could improve outcomes. We discuss the clinical and laboratory components of comprehensive risk evaluation of patients with CLL and our approach to the management of patients with a high to very high risk of disease progression and poor outcome. In addition, we review the challenges and prospects for improving prognostic precision and the development of new drugs to improve the treatment of patients with CLL with a high risk of adverse outcome.

Rituximab in chronic lymphocytic leukemia

Rituximab (Rituxan; iogen Idec, San Diego, CA, USA) is a human-mouse chimeric monoclonal antibody specific for CD20, a surface glycoprotein expressed on B lymphocytes. Administration of rituximab as a single agent to patients with chronic lymphocytic leukemia (CLL) has limited clinical activity, but generally does not eradicate leukemia from the marrow. However, when administered in combination with chemotherapy, rituximab can improve the survival of patients relative to those treated with chemotherapy alone. As a result of this, the US Food and Drug Administration approved the use of rituximab in previously untreated and previously treated CD20-positive CLL in combination with fludarabine monophosphate and cyclophosphamide. The results of clinical studies evaluating the activity of rituximab when used alone or in combination with other antileukemia agents for the treatment of this disease are reviewed here.

What is the best frontline therapy for patients with CLL and 17p deletion?

Chronic lymphocytic leukemia (CLL) is a lymphoproliferative disease with significant variation in disease progression, response to therapy, and survival outcome. Deletions of 17p or mutations of TP53 have been identified as one of the poorest prognostic factors, being predictive of short time for disease progression, lack of response to therapy, short response duration, and short overall survival. The treatment of patients with CLL has improved significantly with the development of chemoimmunotherapy, but this benefit was not pronounced in patients with 17p deletion. We compare various treatment strategies used in these patients, including FCR-like chemoimmunotherapy, alemtuzumab, other antibody combinations, or novel targeted therapies with promising results. Allogeneic stem cell transplantation offers the possibility for long-term disease control in these patients and should be considered early in younger, transplant-eligible patients. The current state of therapy is far from optimal and resources should be applied to studying therapeutic options for patients who have CLL with loss of p53 function.

Role of rituximab in first-line treatment of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a biologically heterogeneous illness that primarily afflicts the elderly. For many decades, the initial therapy for most patients requiring treatment was limited to single-agent alkylator therapy. Within the last two decades, we have seen remarkable progress in understanding the biology of CLL and the development of more effective treatment strategies that have employed monoclonal antibodies, such as rituximab (anti-CD20). Furthermore, recognition of the synergy between fludarabine, cyclophosphamide, and rituximab (FCR) prompted investigators to explore the clinical activity of FCR in Phase II and III trials in patients with relapsed/refractory or previously untreated CLL. On the basis of these findings, the US Food and Drug Administration (FDA) recently approved rituximab in combination with fludarabine and cyclophosphamide for the treatment of patients with relapsed/refractory or previously untreated CD20-postive CLL. Recent data from a randomized Phase III trial has confirmed improved overall survival with FCR in patients with previously untreated CLL. However, FCR is not for everyone. More tolerable regimens using rituximab for the elderly and less fit patients are being pursued in clinical trials. Recent Phase II trials have explored potentially less myelosuppressive approaches by using lower doses of fludarabine and cyclophosphamide, replacing fludarabine with pentostatin, and combining rituximab with chlorambucil. Furthermore new biomarkers predictive of early disease progression have prompted investigators to explore the benefits of early treatment with rituximab combined with other agents. In addition to the proven utility of rituximab as a frontline agent for CLL, rituximab has a favorable toxicity profile both as a single agent and in combination with chemotherapy. The majority of adverse events are Grade 1 and 2 infusion-related reactions (fevers, chills, and rigors) and occur with the first dose of rituximab. The improved tolerability observed with second and subsequent infusions allows for shorter infusion times. Rituximab's proven activity and favorable toxicity profile has made it an ideal agent for expanding treatment options for patients with CLL, the majority of whom are elderly.

The spectrum of use of rituximab in chronic lymphocytic leukemia

The monoclonal chimeric anti-CD20 antibody, rituximab, has considerably improved therapeutic outcome in B-cell chronic lymphocytic leukemia. Rituximab has limited clinical activity when used as a single agent. The combination of the monoclonal antibody with fludarabine-based regimens clearly demonstrated, in Phase II and randomized trials, an increase in clinical efficacy in previously untreated and pretreated patients. Furthermore the addition of rituximab enabled the eradication of minimal residual disease, which is correlated with the prognosis in a high proportion of patients. Although the combination of rituximab with fludarabine-based regimens increased myelosuppression and immunosuppression, incidence of infections did not increase. The benefit of adding rituximab to other purine analogs or other chemotherapeutic combination regimens has also been explored. Moreover there could be a role for achieving better quality of responses with the combination of different monoclonal antibodies, considering that they target different antigens and exert different mechanism of action. Although the role of rituximab as maintenance therapy in low grade non-Hodgkin's lymphomas has been determined, the benefit and optimal schedule in chronic lymphocytic leukemia are still under investigation. This review brings together knowledge of the pharmacokinetics, mechanism of action and clinical use of rituximab in chronic lymphocytic leukemia.