Changing paradigms in the treatment of chronic lymphocytic leukemia

The impact of low-dose carcinogens and environmental disruptors on tissue invasion and metastasis

The purpose of this review is to stimulate new ideas regarding low-dose environmental mixtures and carcinogens and their potential to promote invasion and metastasis. Whereas a number of chapters in this review are devoted to the role of low-dose environmental mixtures and carcinogens in the promotion of invasion and metastasis in specific tumors such as breast and prostate, the overarching theme is the role of low-dose carcinogens in the progression of cancer stem cells. It is becoming clearer that cancer stem cells in a tumor are the ones that assume invasive properties and colonize distant organs. Therefore, low-dose contaminants that trigger epithelial-mesenchymal transition, for example, in these cells are of particular interest in this review. This we hope will lead to the collaboration between scientists who have dedicated their professional life to the study of carcinogens and those whose interests are exclusively in the arena of tissue invasion and metastasis.

Superior efficacy of rituximab-based chemoimmunotherapy as an initial therapy in newly diagnosed patients with B cell indolent lymphomas: long-term results from a single center in China

Background

Rituximab has been confirmed to improve the survival of patients with B cell indolent non-Hodgkin lymphomas (B-iNHLs) in Western world as previously reported, however, it is rarely reported in Chinese cohort. This study is to investigate the efficacy and safety of rituximab-based chemoimmunotherapy and select subpopulations most sensitive to the regimen in Chinese B-iNHL patients.

Methods

334 B-iNHL patients from our center were retrospectively assessed.

Results

Patients received R-based chemoimmunotherapy showed significantly higher rates of overall response (OR) (93.0 % vs. 53.4 %, P < 0.001) and complete response (CR) (63.3 % vs. 16.0 %, P < 0.001) compared with the patients received other therapies. Survival analysis showed that rituximab-based chemoimmunotherapy could obviously improve the progression-free survival (PFS) (110 vs. 49 months, P = 0.001) and overall survival (OS) (120 vs. 72 months, P < 0.001) in patients with B-iNHLs. Interestingly, in chronic lymphocytic leukemia (CLL) patients, we found that the patients with β2-microglobulin (β2-MG) < 3.5 mg/L, lactate dehydrogenase (LDH) < 220 U/L, zeta-chain-associated protein kinase 70 (ZAP-70) negative, and non high-risk genetic abnormality could achieve more benefits from R-based regimens with higher CR rate (P = 0.003, 0.029, 0.013 and 0.038, respectively). Meanwhile, more CLL patients achieved minimal residual disease (MRD) negative after rituximab-based treatment (46.5 % vs. 10.3 %, P < 0.001). Moreover, CLL patients with MRD < 1 %, LDH < 220 U/L, complete remission (CR) or partial remission (PR), β2-MG < 3.5 mg/L and non high-risk cytogenetic abnormality showed superior outcome compared to the controls (P = 0.001, 0.000, 0.000, 0.001 and 0.013, respectively). No other side-effects increased in chemoimmunotherapy group except the elevation of grade 3–4 neutropenia.

Conclusions

Our results demonstrate the superior efficacy of rituximab–based chemoimmunotherapy as an initial therapy in Chinese cohort with newly diagnosed B-iNHLs and further identify subpopulations that are more sensitive to R-based chemoimmunotherapy in CLL group.

Renal human organic anion transporter 3 increases the susceptibility of lymphoma cells to bendamustine uptake

Chronic lymphatic leukemia (CLL) is often associated with nephritic syndrome. Effective treatment of CLL by chlorambucil and bendamustine leads to the restoration of renal function. In this contribution, we sought to elucidate the impact of organic anion transporters (OATs) on the uptake of bendamustine and chlorambucil as a probable reason for the superior efficacy of bendamustine over chlorambucil in the treatment of CLL. We examined the effects of structural analogs of p-aminohippurate (PAH), melphalan, chlorambucil, and bendamustine, on OAT1-mediated [(3)H]PAH uptake and OAT3- and OAT4-mediated [(3)H]estrone sulfate (ES) uptake in stably transfected human embryonic kidney-293 cells. Melphalan had no significant inhibitory effect on any OAT, whereas chlorambucil reduced OAT1-, OAT3-, and OAT4-mediated uptake of PAH or ES down to 14.6%, 16.3%, and 66.0% of control, respectively. Bendamustine inhibited only OAT3-mediated ES uptake, which was reduced down to 14.3% of control cells, suggesting that it interacts exclusively with OAT3. The IC50 value for OAT3 was calculated to be 0.8 μM. Real-time PCR experiments demonstrated a high expression of OAT3 in lymphoma cell lines as well as primary CLL cells. OAT3-mediated accumulation of bendamustine was associated with reduced cell proliferation and an increased rate of apoptosis. We conclude that the high efficacy of bendamustine in treating CLL might be partly contributed to the expression of OAT3 in lymphoma cells and the high affinity of bendamustine for this transporter.

Evaluation of bendamustine in combination with fludarabine in primary chronic lymphocytic leukemia cells

The fludarabine and cyclophosphamide couplet has become the backbone of the chronic lymphocytic leukemia (CLL) standard of care. Although this is an effective treatment, it results in untoward toxicity. Bendamustine is a newly approved and better-tolerated alkylating agent. We hypothesized that similar to cyclophosphamide, bendamustine-induced DNA damage will be inhibited by fludarabine, resulting in increased cytotoxicity. To test this hypothesis and the role of the stromal microenvironment in this process, we treated CLL lymphocytes in vitro with each drug alone and in combination. Simultaneous or prior addition of fludarabine to bendamustine resulted in maximum cytotoxicity assayed by 3,3'-dihexyloxacarbocyanine iodine negativity, annexin positivity, and poly (adenosine 5'-diphosphate-ribose) polymerase cleavage. Cytotoxicity elicited by combination of both agents was similar in these malignant B cells cultured either in suspension or on marrow stroma cells. Cell death was associated with DNA damage response, which was determined by phosphorylation of H2AX and unscheduled DNA synthesis. H2AX activation was maximum with the drug combination, and unscheduled DNA synthesis induced by bendamustine was blocked by fludarabine. In parallel, ATM, Chk2, and p53 were phosphorylated and PUMA was induced. Cell death was caspase independent; however, caspases did decrease levels of Mcl-1 survival protein. These data provide a rationale for combining fludarabine with bendamustine for patients with CLL.

Immunotherapy for chronic lymphocytic leukemia in the era of BTK inhibitors

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

The changing paradigm of chronic lymphocytic leukemia management

B cell-chronic lymphocytic leukemia (CLL), the commonest adult leukemia in western world, is today most often diagnosed at early-stage, following the accidental detection of lymphocytosis during a routine blood analysis. Moreover, the expectations of CLL patients have dramatically changed in the past decade and for the first time a significant overall survival improvement has been demonstrated in the disease--at least in the younger and fit patients--with the use of the FCR regimen, which combines rituximab fludarabine and cyclophosphamide. New drugs and new regimens are currently being developed for the relapsed patients and for those too old or too frail to receive aggressive treatments. Some of these promising compounds will likely be part of the future front-line treatments. Additionally, the increasing knowledge on the molecular features that predict the clinical outcome may soon result in a molecular classification of the disease. These acquisitions are producing a migration from palliative care to a curative and individually-tailored approach. In this review we tried to summarize the advances achieved in the past decade and help the specialists in internal medicine and the general practitioners to understand the completely changed scenario in which the disease should nowadays be managed.

Reduction of complement factor H binding to CLL cells improves the induction of rituximab-mediated complement-dependent cytotoxicity

A main effector mechanism of rituximab (RTX) is the induction of complement-dependent cytotoxicity (CDC). However, this effector function is limited, because CLL cells are protected from complement-induced damage by regulators of complement activation (RCAs). A prominent RCA in fluid phase is factor H (fH), which has not been investigated in this context yet. Here, we show that fH binds to CLL cells and that human recombinant fH-derived short-consensus repeat 18–20 (hSCR18–20) interferes with this binding. In complement-based lysis assays, CLL cells from therapy-naive patients were differently susceptible to RTX-induced CDC and were defined as CDC responder or CDC non-responder, respectively. In CDC responders, but notably also in non-responders, hSCR18–20 significantly boosted RTX-induced CDC. Killing of the cells was specific for CD20⁺ cells, whereas CD20⁻ cells were poorly affected. CDC resistance was independent of expression of the membrane-anchored RCAs CD55 and CD59, although blocking of these RCAs further boosted CDC. Thus, inhibition of fH binding by hSCR18–20 sensitizes CLL cells to CDC and may provide a novel strategy for improving RTX-containing immunochemotherapy of CLL patients.

Demographics, treatment patterns, safety, and real-world effectiveness in patients aged 70 years and over with chronic lymphocytic leukemia receiving bendamustine with or without rituximab: a retrospective study

OBJECTIVES

Bendamustine is a unique cytotoxic agent active against various human malignancies, including chronic lymphocytic leukemia (CLL). In vitro studies suggest that cytotoxic activity of bendamustine on CLL-derived cells is synergized by rituximab. A retrospective chart review was conducted to characterize treatment-naïve outpatients and those with relapsed disease aged 70 years and over with CLL receiving bendamustine (with or without rituximab) and to evaluate real-world patterns of care, safety, and effectiveness.

METHODS

Using McKesson Specialty Care/US Oncology Network iKnowMed databases, 91 outpatients with at least two recorded visits and at least two cycles of bendamustine monotherapy or bendamustine-rituximab combination therapy were identified and included. Mean age at diagnosis and start of first therapy was 70.3 and 77.4 years respectively, and 63.7% of patients were men.

RESULTS

Observed overall response rate was 56.3% in pooled treatment-naïve patients [n = 9; complete response (CR) 18.8%; partial response (PR) 37.5%; nodular partial response (nPR) 0%] and 58.7% in pooled patients with relapsed disease (n = 44; CR 13.3%; PR 44.0%; nPR 1.3%). Median time to progressive disease has not been reached for the 16 treatment-naïve patients (median follow up 15.1 months), and was 18.4 months for those with relapsed disease (n = 73). No unexpected toxicities were observed. Overall rate of blood/bone marrow toxicities (all grades) was 40.7%; grade 3/4 rates were 18.8% in treatment-naïve patients and 25.3% in those with relapsed disease. Most frequent nonhematologic adverse events were fatigue and rash.

CONCLUSION

In this retrospective chart review of 91 outpatients with CLL aged 70 years and over, bendamustine (with or without rituximab) was an effective therapeutic option with manageable toxicity.

High expression of hematopoietic cell specific Lyn substrate-1 (HS1) predicts poor survival of B-cell chronic lymphocytic leukemia patients

B-cell chronic lymphocytic leukemia (B-CLL) is the most common leukemia in adults in western countries. HS1 protein regulates leukemic cell migration and homing, and can indirectly promote disease progression and influence patient survival. The aim of this study was to evaluate HS1 expression in CLL patients in connection with other known prognostic factors and patients' survival.

METHODS

90 untreated CLL patients were included into the study. The control group consisted of 28 healthy matched people. HS1 detection was performed by western-blotting. Mutational status of IgVH, as well as CD38 and ZAP70 expression was also analyzed.

RESULTS

HS1 expression was significantly higher in CLL patients comparing to controls. Positive correlation was shown between HS1 and: age (p=0.0454), Rai stage (p=0.0412), leukocytosis (p=0.0129) and beta-2-microglobulin (p=0.0342). Patients with lymphocyte doubling time shorter or equal to 6 months had higher expression of HS1. Patients with higher HS1 expression had shorter survival than those with lower HS1 expression (p=0.0329).

CONCLUSIONS

We showed, that high HS1 expression predicts poor survival of chronic lymphocytic leukemia patients.

Monoclonal antibodies for non-Hodgkin's lymphoma: state of the art and perspectives

Monoclonal antibodies have been the most successful therapeutics ever brought to cancer treatment by immune technologies. The use of monoclonal antibodies in B-cell Non-Hodgkin's lymphomas (NHL) represents the greatest example of these advances, as the introduction of the anti-CD20 antibody rituximab has had a dramatic impact on how we treat this group of diseases today. Despite this success, several questions about how to optimize the use of monoclonal antibodies in NHL remain open. The best administration schedules, as well as the optimal duration of rituximab treatment, have yet to be determined. A deeper knowledge of the mechanisms underlying resistance to rituximab is also necessary in order to improve the activity of this and of similar therapeutics. Finally, new antibodies and biological agents are entering the scene and their advantages over rituximab will have to be assessed. We will discuss these issues and present an overview of the most significant clinical studies with monoclonal antibodies for NHL treatment carried out to date.

Bendamustine with or without rituximab in the treatment of relapsed chronic lymphocytic leukaemia: an Italian retrospective study

To retrospectively assess the efficacy of bendamustine alone and with rituximab (R-B), 109 patients with relapsed chronic lymphocytic leukaemia (CLL) were enrolled in 24 Italian centres. The median age was 66 years (range 39-85). Forty-three percent of patients had relapsed and 57% were resistant (median previous therapies = 3; range 1-8). Twenty-two patients received bendamustine alone and 87 patients received R-B (median B dosage: 100 mg/m(2) per day, range 90-130 mg/m(2) per day). The overall response rate was 69·6% (complete response 28·6%; partial response 41%), and was significantly higher in patients treated with R-B (P = 0·014) and in those responsive to the previous treatment (P=0·04). After a median follow-up of 7·9 months (range 1-148), the median progression-free survival was 16 months and the median duration of response was 13 months. Median overall survival (OS) was 16·8 months for the whole cohort; patients not responding to the treatment had a significantly worse outcome than those who attained a response (P = 0·0001). In multivariate analysis, only resistant disease status at start of bendamustine treatment (HR 3·2, 95% CI 1·4-7·3, P = 0·006) had an independent prognostic value for OS. Toxicity was manageable and mostly haematological. In conclusion, in our experience R-B was an effective and well-tolerated treatment for relapsed/refractory CLL patients, producing a remarkable high CR rate and mild toxicity.

Rituximab: a review of its use in chronic lymphocytic leukaemia, low-grade or follicular lymphoma and diffuse large B-cell lymphoma

Rituximab (MabThera, Rituxan) is a chimeric mouse anti-human CD20 monoclonal antibody. This article reviews the use of intravenous rituximab in the treatment of chronic lymphocytic leukaemia (CLL), low-grade or follicular lymphoma, and diffuse large B-cell lymphoma. The addition of rituximab to fludarabine plus cyclophosphamide significantly prolonged progression-free survival both in previously untreated patients with CLL and in those with relapsed or refractory CLL, according to the results of two randomized, open-label, multicentre trials. In patients with previously untreated advanced follicular lymphoma, the addition of rituximab to chemotherapy (cyclophosphamide, doxorubicin, vincristine and prednisone [CHOP], cyclophosphamide, vincristine and prednisone [CVP], mitoxantrone, chlorambucil and prednisolone, or cyclophosphamide, doxorubicin, etoposide and prednisolone) was generally associated with better outcomes than chemotherapy alone in randomized, multicentre trials. In a similarly designed trial, progression-free survival was significantly longer in previously untreated patients with follicular lymphoma, other indolent lymphomas or mantle-cell lymphoma who received rituximab plus bendamustine than in those receiving rituximab plus CHOP. Monotherapy with rituximab also demonstrated efficacy in patients with relapsed or refractory low-grade or follicular lymphoma, according to the results of noncomparative trials. In terms of maintenance therapy, progression-free survival was significantly prolonged with rituximab maintenance therapy versus observation alone in patients with advanced indolent lymphoma who had not progressed following first-line therapy with CVP and in patients with relapsed or refractory follicular lymphoma who had responded to CHOP (with or without rituximab), according to the results of randomized, open-label, multicentre trials. In four randomized, open-label, multicentre trials in younger or elderly patients with previously untreated diffuse large B-cell lymphoma, event-free survival, failure-free survival, progression-free survival and overall survival were generally improved to a significant extent by the addition of rituximab to CHOP or CHOP-like chemotherapy. Intravenous rituximab was generally well tolerated in patients with CLL, low-grade or follicular lymphoma, or diffuse large B-cell lymphoma, both as monotherapy and when administered in combination with chemotherapy. Infusion reactions were one of the most commonly occurring adverse events in patients receiving intravenous rituximab. The results of pharmacoeconomic modelling analyses demonstrated that rituximab appears to be cost effective in patients with previously untreated follicular lymphoma, in patients with follicular lymphoma receiving rituximab maintenance therapy following treatment for relapsed or refractory disease and in patients with previously untreated diffuse large B-cell lymphoma. In conclusion, rituximab remains a valuable therapy in patients with CLL, low-grade or follicular lymphoma and diffuse large B-cell lymphoma and, in a variety of treatment settings, represents the standard of care.