Low-dose fludarabine increases rituximab cytotoxicity in B-CLL cells by triggering caspases activation in vitro

Frontline Management of Waldenström Macroglobulinemia with Chemoimmunotherapy

Despite the introduction of effective novel agents, chemoimmunotherapy (CIT), with its widespread use, retains relevance and is one of the 2 vastly disparate strategies to treat Waldenström macroglobulinemia (WM), the alternative being the Bruton tyrosine kinase inhibitor (BTKi)-based approach. Considerable evidence over the past decades supports the integration of the monoclonal anti-CD20 antibody, rituximab, to the CIT backbone in WM, a CD20+ malignancy. Besides substantial efficacy, the finite duration of the treatment, coupled with lower rates of cumulative and long-term, clinically significant adverse effects and greater affordability, make CIT appealing, notwithstanding the lack of quality-of-life data with such an approach in WM. A phase 3 randomized controlled trial reported substantially higher efficacy and a more favorable safety profile of the bendamustine-rituximab (BR) doublet compared with R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) among patients with WM. Subsequent studies reaffirmed its high efficacy and tolerability, making BR the mainstay of managing treatment-naïve patients with WM. High-quality evidence supporting the use of BR over Dexamethasone, Rituximab, and Cyclophosphamide (DRC), another commonly used regimen, is lacking, as is its comparison with the continuous BTKi-based approach. However, DRC appeared less potent than BR in cross-trial comparisons and retrospective series involving treatment-naïve patients with WM. Additionally, a recent retrospective, international study demonstrated comparable outcomes with fixed-duration BR and continuous ibrutinib monotherapy among previously untreated, age-matched patients exhibiting MYD88^L265P mutation. However, unlike ibrutinib, BR appears effective irrespective of the MYD88 mutation status. CIT, preferably BR, is well suited to serve as the control arm (comparator) regimen against which novel targeted agents may be evaluated as frontline therapies for WM in high-quality trials. Purine analog-based CIT has been extensively evaluated in WM, although its use has waned, even in the multiply relapsed patient population, as effective and safer alternatives emerge.

Towards the Application of Atorvastatin to Intensify Proapoptotic Potential of Conventional Antileukemic AgentsIn Vitro

It has been previously revealed that statins used at high concentrations display antileukemic potential towards chronic lymphocytic leukemia (CLL) cells. However, their usage alone in clinical practice may be limited due to possible side effects of high doses of these drugs. On the other hand, combined treatment of leukemia with statins and the conventional chemotherapeutics is questionable because of unknown influence of the first on the standard treatment results. This study has revealed thatin vitroatorvastatin increases the proapoptotic potential of cladribine and mafosfamide in CLL cells isolated from peripheral blood of patients. Moreover, a preincubation with the above statin sensitizes leukemic cells to CM-induced apoptosis even at small concentrations of the drug. The usage of atorvastatin together with or followed by the conventional chemotherapy should be considered as therapeutic option for the treatment for this leukemia. Interestingly, CM-resistant patients might have the biggest benefits from atorvastatin administration.

Current and future therapeutic approach for Waldenström's macroglobulinemia

Waldenström's macroglobulinemia is a rare B-cell malignancy defined by medullar infiltration by clonal lymphoplasmocytic cells and monoclonal IgM secretion. Treatment is reserved for symptomatic patients. The main first-line treatment strategies combine immunotherapy (principally the anti-CD20 monoclonal antibody rituximab) with chemotherapeutic agents, including alkylating agents, purine analogs and/or bortezomib. The overall response rate to these conventional treatments is between 70 and 90%, but a cure cannot be expected. For patients with relapsed or refractory disease, drugs that were not used for first-line treatment and other agents such as immunomodulators can be tried, but the response rate is generally lower and the responses are shorter lived. Recently, advances in our understanding of the biology of Waldenström's macroglobulinemia have led to the development of new drugs targeting hyperactive pathways. This review focuses on current treatment options and on new therapeutic developments.

The role of chemotherapy in managing chronic lymphocytic leukemia: optimizing combinations with targeted therapy

For many years, alkylating agents were the standard treatment for chronic lymphocytic leukemia (CLL). The advent of purine analogs improved response rates, but not overall survival, and although the monoclonal antibody rituximab is generally active against B-cell malignancies, it has demonstrated limited benefits as monotherapy for the treatment of CLL. However, specific combinations of chemotherapy, antibodies and targeted therapies have demonstrated additive or synergistic activity in CLL cells and deliver substantial clinical benefits. A greater understanding of the actions of chemotherapies and targeted agents on cellular pathways will advance the development of rationally designed combinations corresponding to individual patients' disease profiles.

Toward personalized therapy for chronic lymphocytic leukemia: DSC and cDNA microarray assessment of two cases

The differences in clinical course of chronic lymphocytic leukemia could have an impact on variations in a patient's response to therapy. Our published results revealed that thermal transition (95 ± 5°C) in differential scanning calorimetry profiles appear to be characteristic for the advanced stage of CLL. Moreover, a decrease/loss of this transition in nuclei from leukemic cells exposed to drugs ex vivo could indicate their diverse efficacy. It seems that the lack of changes in thermal profile could predict patient's drug resistance. In this study, we demonstrate the results obtained after drug treatment of leukemic cells by calorimetry, apoptosis-related parameters involved in expression of genes using cDNA microarray and western blot. These data were compared with the patients' clinical parameters before and after RCC therapy (rituximab + cladribine + cyclophosphamide). The complementary analysis of studied cases with opposite clinical response (CR or NR) revealed a strong relationship between clinical data, differences in thermal scans and apoptosis-related gene expression. We quantified expression of eight of apoptosis-related 89 genes, i.e., NOXA, PUMA, APAF1, ESRRBL1, CASP3, BCL2, BCL2A1 and MCL1. Particular differences in NOXA and BCL2 expression were revealed. NOXA expression in cells of patients who achieved a complete response to RCC therapy was 0.44 times higher in comparison to control ones. Interestingly, in the case of patients who did not respond to immunotherapy, NOXA expression was highly downregulated (RQ = 4.39) as compared with untreated cells. These results were confirmed by distinct cell viability, protein expression as well as by differences in calorimetry profiles.

Fludarabine-containing chemotherapy for patients with previously untreated low-grade non-Hodgkin's lymphoma

BACKGROUND

The clinical efficacy and safety of fludarabine combination chemotherapy was investigated for the treatment of previously untreated patients with low-grade (NHL).

METHODS

Twenty-five patients who were newly diagnosed as low-grade NHL were treated with fludarabine combination chemotherapy. Fludarabine combination regimens consisted of fludarabine, mitoxantrone and dexamethasone or fludarabine, cyclophosphamide and mitoxantrone with or without rituximab and repeated every 4 weeks.

RESULTS

The median age was 60 years (range, 35-77 years), with 13 of 25 patients (52%) ≥60 years of age. Seven of 25 patients (28%) with an intermediate risk follicular lymphoma international prognostic index (FLIPI) and 9 of 25 patients (36%) with a high risk FLIPI were enrolled in this study. The delivered median number of chemotherapy was six (range, 2-9 cycles). The overall response rate with fludarabine-based treatment was 88%, including 52% complete remission and 36% partial remission. During the median follow-up of 19 months, the estimated 2-year event-free survival was 63±10% (95% CI, 43-83) and the 2-year overall survival was 78±9% (95% CI, 60-96). Fludarabine combination chemotherapy was frequently associated with grade 3 or 4 neutropenia in 84% patients. However, neutropenic infection was observed in only one (4%) patient. Four patients (16%) showed grade 3 or more non-hematologic toxicities, such as acute coronary syndrome, intracranial hemorrhage, anaphylaxis and gastric cancer.

CONCLUSION

Fludarabine-combination treatment was a highly active regimen with well toleration in untreated low-grade NHL.

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.