Randomized comparison of cladribine alone or in combination with cyclophosphamide, and cyclophosphamide, vincristine and prednisone in previously untreated low‐grade B‐cell non‐Hodgkin lymphoma patients

Solute Carrier Nucleoside Transporters in Hematopoiesis and Hematological Drug Toxicities: A Perspective

Simple Summary

Anticancer nucleoside analogs are promising treatments that often result in damaging toxicities and therefore ineffective treatment. Mechanisms of this are not well-researched, but cellular nucleoside transport research in mice might provide additional insight given transport’s role in mammalian hematopoiesis. Cellular nucleoside transport is a notable component of mammalian hematopoiesis due to how mutations within it relate to hematological abnormities. This review encompasses nucleoside transporters, focusing on their inherent properties, hematopoietic role, and their interplay in nucleoside drug treatment side effects. We then propose potential mechanisms to explain nucleoside transport involvement in blood disorders. Finally, we point out and advocate for future research areas that would improve therapeutic outcomes for patients taking nucleoside analog therapies.

Abstract

Anticancer nucleoside analogs produce adverse, and at times, dose-limiting hematological toxicities that can compromise treatment efficacy, yet the mechanisms of such toxicities are poorly understood. Recently, cellular nucleoside transport has been implicated in normal blood cell formation with studies from nucleoside transporter-deficient mice providing additional insights into the regulation of mammalian hematopoiesis. Furthermore, several idiopathic human genetic disorders have revealed nucleoside transport as an important component of mammalian hematopoiesis because mutations in individual nucleoside transporter genes are linked to various hematological abnormalities, including anemia. Here, we review recent developments in nucleoside transporters, including their transport characteristics, their role in the regulation of hematopoiesis, and their potential involvement in the occurrence of adverse hematological side effects due to nucleoside drug treatment. Furthermore, we discuss the putative mechanisms by which aberrant nucleoside transport may contribute to hematological abnormalities and identify the knowledge gaps where future research may positively impact treatment outcomes for patients undergoing various nucleoside analog therapies.

A comparison of caspase 3 expression in the endocrine and exocrine parts of the pancreas after cladribine application according to the "leukemic" schema

The therapeutic effects of the immunosuppressive agent, cladribine, have been demonstrated by its toxicity to cells. However, its effects on healthy cells of the body is poorly understood. The aim of study was, hence, to, firstly, evaluate the morphology of the endocrine and exocrine pancreas after the administration of cladribine according to the "leukemic" schema, and, secondly, to assess its impact on the intensity of apoptosis. The experiment was carried out on female Wistar rats which were placed within the control group KA, and the experimental groups: A and A-bis. In the experimental groups, Cladribine was administered according to the cycle used to treat human hairy cell leukemia. In group A, the material was taken 24 hours after administration of the last dose of the drug, while in group A-bis, this was done after a 4 weeks break. The reaction was assessed to be average in 80% of all cells in group A, and in 64% of all acinar cells in group KA, while in group A-bis, the majority of the exocrine cells demonstrated a lack of immunohistochemical response (72%). Moreover, most endocrine cells (60%) in group A-bis revealed a strong reaction, while in Group A, the corresponding figure is a little over 34%. A comparison of the severity of the caspase 3 expression in both the exocrine and endocrine pancreas showed significant differentiation results between the group KA and group A-bis, and between group A and A-bis (p < 0.0001). In can be concluded that endocrine cells are more sensitive to cladribine than are exocrine cells.

Infiltration of the thyroid gland by T-cell prolymphocytic leukemia

BACKGROUND

T-cell prolymphocytic leukemia (T-PLL) is rare, accounting for only 0.06% of all malignant lymphomas, and is classified as a T-cell mature lymphoma. The disease affects mainly elderly patients and is characterized by splenomegaly, lymphadenopathy, skin infiltration, and a high leukocyte count, but thyroid filtration has never been detected as far as we could determine. We report here a case of infiltration of the thyroid gland by T-PLL.

PATIENT FINDINGS

An 89-year-old woman who had been treated for Hashimoto's thyroiditis for 20 years presented with a progressively enlarging thyroid mass accompanied by dyspnea and dysphasia. Atypical lymphocytes with irregular nuclei were observed in the peripheral blood. An open biopsy of the thyroid provided pathological evidence of T-PLL, and bone marrow examination showed infiltration by T-PLL. The diagnosis was therefore infiltration of the thyroid gland by T-PLL. Chemotherapy was initiated, but six months after termination, recurrence of neck swelling was observed. The patient was then treated with radiotherapy, but she died of a major stroke 15 months after onset.

SUMMARY AND CONCLUSION

This is the first report of T-PLL infiltration of the thyroid gland, reminding physicians to keep in mind a broad differential diagnosis when encountering a patient with diffuse thyroid lesions and abnormal lymphocytes in the peripheral blood.

Marginal zone lymphoma: old, new, targeted, and epigenetic therapies

Marginal zone lymphoma (MZL) is an indolent B-cell lymphoma arising from marginal zone B-cells present in lymph nodes and extranodal tissues. MZL comprises 5-17% of all non-Hodgkin's lymphomas in adults. The World Health Organization categorizes MZL into three distinct types based on their site of impact: (1) splenic marginal zone lymphoma (SMZL); (2) nodal marginal zone lymphoma (NMZL); (3) extranodal mucosa-associated lymphoid tissue (MALT) lymphoma, which can be subdivided into gastric and nongastric. The subgroups of MZL share some common features but are different in their biology and behavior. Owing to the rarity of MZL there are few randomized trials available comparing various treatment options and therefore treatment is controversial, lacking standard guidelines. Treatment should be patient tailored and can range from a 'watchful waiting' approach for asymptomatic patients without cytopenias to surgery or localized radiation therapy. Rituximab in combination with chemotherapy has resulted in longer failure-free survival than chemotherapy alone in patients with SMZL. Helicobacter pylori positive gastric MALT shows a good response rate to triple antibiotic therapy. Newer therapies such as bendamustine, everolimus, lenalidomide, vorinostat and phosphoinositide 3-kinase inhibitors are in clinical trials for patients with relapsed or refractory MZL and have shown promising results. We are presently conducting clinical trials testing the efficacy of the epigenetic activity of cladribine as a hypomethylating agent in combination with the histone deacetylase inhibitor (HDACi) vorinostat and rituximab in patients with MZL. Further studies with the newer agents should be done both in newly diagnosed or relapsed/refractory MZL to streamline the care and to avoid the use of toxic chemotherapies as initial treatment.

(-)-Epigallocatechin-3-O-gallate induces nonapoptotic cell death in leukemia cells independent of the 67 kDa laminin receptor

The 67 kDa laminin receptor (67 LR) mediates (-)-epigallocatechin-3-O-gallate (1; EGCG)-67 LR direct action only at physiological concentrations. The relevancy of biological effects of 1 at physiological concentrations to 67 LR was investigated in myeloid and lymphoid leukemia cells using flow cytometric analysis. It was shown that physiological concentrations of 1 suppressed the cell growth of HL60 myeloid leukemia cells and Raji lymphoid leukemic cells independent of 67 LR expression. Moreover, there was no discernible change in the levels of intracellular reactive oxygen species, characteristics of apoptosis such as phosphatidylserine translocation and activated caspase-3. The activity of 1 at physiological concentrations does not depend on direct 67 LR-mediated actions, and this compound induces necrosis-like death of promyelocytic leukemia and non-Hodgkin's lymphoma cells.

Identification of potential surrogate end points in randomized clinical trials of aggressive and indolent non-Hodgkin's lymphoma: correlation of complete response, time-to-event and overall survival end points

BACKGROUND

The correlation between efficacy end points in randomized controlled trials (RCTs) of systemic therapy for non-Hodgkin's lymphoma (NHL) was investigated to identify an appropriate surrogate end point for overall survival (OS).

METHODS

RCTs of previously untreated NHL published from 1990 to 2009 were identified. Associations between absolute differences in efficacy end points were determined using nonparametric Spearman's rank correlation coefficients (r(s)).

RESULTS

Thirty-eight RCTs representing 85 treatment arms for aggressive NHL and 20 RCTs representing 42 arms for indolent NHL were included. For aggressive NHL, differences in 3-year progression-free survival (PFS)/event-free survival (EFS) were high correlated with differences in 5-year OS {r(s) of 0.90 [95% confidence interval (CI) 0.73-0.96]} and linear regression determined that a 10% improvement in 3-year EFS or PFS would predict for a 7% ± 1% improvement in 5-year OS. For indolent histology disease, differences in complete response were strongly correlated with differences in 3-year EFS [r(s) 0.86 (95% CI 0.35-0.97)], but there was no correlation between 3-year time-to-event end points and 5-year OS.

CONCLUSIONS

Improvements in 3-year EFS/PFS are highly correlated with improvements in 5-year OS in aggressive NHL and should be explored as a candidate surrogate end point. Definition of these relationships may inform future clinical trial design and interpretation of interim trial data.

Cladribine combined with rituximab (R-2-CdA) therapy is an effective salvage therapy in relapsed or refractory indolent B-cell non-Hodgkin lymphoma

Although cladribine has been reported to be an active purine analog against indolent B-cell non-Hodgkin lymphoma (B-NHL), there are few reports of combination use of cladribine and rituximab. This multicenter phase II study evaluated the efficacy and toxicity of cladribine with rituximab (R-2-CdA) therapy in relapsed or refractory indolent B-NHL. Twenty patients with the median age of 58.5 yrs (range, 42-72) were enrolled and received R-2-CdA therapy from April 2005 to July 2007. The median number of prior regimens was 2 (range, 1-3), and fifteen patients (75%) were previously treated with rituximab-containing regimens. Disease histology included follicular lymphoma in 16 patients, MALT lymphoma in two patients, nodal marginal B-cell lymphoma in one patient, and lymphoplasmacytic lymphoma in one patient. The overall response rate (ORR) was 90%, with a complete response rate (CRR) of 70%. Estimated median progression-free survival (PFS) time was 22.4 months (95%CI, 10.9-32.6 months) at a median follow-up time of 27 months (range, 12-43). Two-year PFS and 2-yr overall survival (OS) were 52.6% (95%CI, 31.0-73.2%) and 89.5% (95%CI, 66.1-97.3%), respectively. Grade 3 or grade 4 toxicities were neutropenia in 74% and thrombocytopenia in 11%. R-2-CdA therapy was demonstrated to have a high activity with durable PFS and acceptable toxicity in relapsed or refractory indolent B-NHL mostly pretreated with rituximab-containing therapy. Although a large-scale trial is needed for confirmation, R-2-CdA therapy could be a good salvage therapy option in relapsed or refractory indolent B-NHL.

Beyond hairy cell: the activity of cladribine in other hematologic malignancies

Before the contemporary development of rationally designed antineoplastic therapies, cladribine was identified as a lymphocyte-specific agent. Its profound impact on the natural history of hairy cell leukemia, with responses approaching 100% and a median duration of response of nearly a decade after only a single 7-day course, is well known and revolutionized the treatment of hairy cell leukemia. However, cladribine's impressive activity in other lymphoproliferative disorders has been generally underappreciated. Multiple single-arm phase 2 trials have demonstrated cladribine's potency across the full spectrum of lymphoid malignancies. In a limited number of phase 3 trials and cross-study analyses, cladribine compared favorably with fludarabine, another purine nucleoside analog that is more commonly used in the treatment of indolent lymphoid malignancies. Cladribine has been noted to have particular activity among lymphoid disorders with few effective therapies, specifically, chronic lymphocytic leukemia, lymphoplasmacytic lymphoma, marginal zone lymphoma, and mantle cell lymphoma. Recently approved novel agents may act in synergy with cladribine for these conditions and should be incorporated into future clinical studies.

Cladribine: not just another purine analogue?

Cladribine was synthesized as a purine analogue drug that inhibited adenosine deaminase. It received FDA approval in the 1980s for treatment of hairy cell leukemia. Given its toxicity towards lymphocytes and its corresponding immunosuppressive effects, it has been studied and found efficacious in a variety of hematologic malignancies and autoimmune conditions, most recently multiple sclerosis. This review highlights pharmacological, toxicological and clinical data for the use of cladribine. It also discusses existing and new mechanisms that may contribute to its unique clinical activity. Emerging data show that in addition to its known purine nucleoside analogue activity, cladribine possesses epigenetic properties, inhibiting S-adenosylhomocysteine hydrolase and DNA methylation. This may contribute to its efficacy and highlights the importance of studying combination therapy with other epigenetic or targeted agents. Clinical trials are underway in a variety of malignant and nonmalignant conditions.

Safety profile of IBD: lymphoma risks

This article describes the cancer risks of commonly used inflammatory bowel disease (IBD) medications, with an emphasis on hematologic malignancy risks. The increasing use of immunosuppressant therapies in the treatment of IBD has raised this question to an even greater importance. Studies evaluating these medications are complicated due to varying disease severity and concomitant use of other immunosuppressant medication. The potential risks of all therapies must be weighed against the benefits these therapies can offer these patients.

Safety profile of IBD: lymphoma risks

This article describes the cancer risks of commonly used inflammatory bowel disease (IBD) medications, with an emphasis on hematologic malignancy risks. The increasing use of immunosuppressant therapies in the treatment of IBD has raised this question to an even greater importance. Studies evaluating these medications are complicated due to varying disease severity and concomitant use of other immunosuppressant medication. The potential risks of all therapies must be weighed against the benefits these therapies can offer these patients.

Current status of older and new purine nucleoside analogues in the treatment of lymphoproliferative diseases

For the past few years more and more new cytotoxic agents active in the treatment of hematological malignancies have been synthesized and become available for either in vitro studies or clinical trials. Among them the class of antineoplastic drugs belonging to the purine nucleoside analogues group (PNAs) plays an important role. Three of them: pentostatin (DCF), cladribine (2-CdA) and fludarabine (FA) were approved by Food and Drug Administration (FDA) for the treatment of hematological malignancies. Recently three novel PNAs: clofarabine (CAFdA), nelarabine (ara-G) and forodesine (immucillin H, BCX-1777) have been synthesized and introduced into preclinical studies and clinical trials. These agents seem to be useful mainly for the treatment of human T-cell proliferative disorders and they are currently undergoing clinical trials in lymphoid malignancies. However, there are also several studies suggesting the role of these drugs in B-cell malignancies. This review will summarize current knowledge concerning the mechanism of action, pharmacologic properties, clinical activity and toxicity of PNAs accepted for use in clinical practice, as well as new agents available for clinical trials.