PubMed Health⌕ Search

Biomedical subjects

E Van Den Neste

Publications and source records attributed to E Van Den Neste.

18 recordsLinked to original sources
PubMed2004

High incidence of complications after 2-chloro-2'-deoxyadenosine combined with cyclophosphamide in patients with advanced lymphoproliferative malignancies.

The combination of purine analogs with alkylating agents is able to produce a synergistic antitumoral effect. However, the addition of immunosuppressive and DNA-targeting agents might increase purine analog-related complications. The risk for serious complications was evaluated in 38 patients treated with 2-chloro-2'-deoxyadenosine (CDA) and cyclophosphamide (CP). The diagnoses were chronic lymphocytic leukemia (CLL) in 15, Waldenström's macroglobulinemia in 4, mantle cell lymphoma in 6, follicular non-Hodgkin's lymphoma (NHL) in 10, and other low-grade NHL in 3 patients. All patients were pretreated (median: 2 lines, range: 1-5) and 23 (61%) were refractory. The patients received a median of two courses (range: 1-5) of 5.6 mg/m(2) CDA, followed by a median of 200 mg/m(2) CP, for 3 days. The response rate was 51% [complete remission (CR): 14%, partial remission (PR): 38%]. Grade 3/4 infections occurred in 16 (42%) patients. Dose-limiting cytopenias were seen in 22 (58%) patients. In 12 (32%) patients, autoimmune manifestations developed requiring treatment in most of them. Second cancers arose in five (13%) patients (myelodysplastic syndrome/acute myelocytic leukemia in three, lung cancer in two). Multivariate analysis showed that cytopenias, gender (F), prior radiotherapy, and age (>65 years) predicted for the complications seen after CDA-CP. To conclude, because of the high incidence of complications, caution is warranted in selecting patients with advanced lymphoid malignancies for the CDA-CP protocol.

Adult↗
PubMed2002

2-Chloro-2'-deoxyadenosine inhibits DNA repair synthesis and potentiates UVC cytotoxicity in chronic lymphocytic leukemia B lymphocytes.

2-Chloro-2'-deoxyadenosine (CdA) is a deoxyadenosine analogue which targets enzymes involved in DNA synthesis, and hence might interfere with the resynthesis step of DNA repair. We tested this hypothesis in resting B cell chronic lymphocytic leukemia (B-CLL) lymphocytes, after firstly characterizing unscheduled DNA synthesis occurring in these cells. We observed that the spontaneous incorporation of [methyl-3H]thymidine (dThd) into DNA of B-CLL cells was not completely inhibitable by hydroxyurea (HU) which blocks DNA replication. In addition, in the presence of HU, dThd incorporation could be upregulated by UVC radiation or DNA alkylation, without re-entry of the cells into S phase. CdA was found to inhibit both spontaneous and upregulated DNA synthesis in B-CLL cells. Phosphorylation of CdA was essential to exert this effect. We finally observed a strong synergistic cytotoxicity between UV light and CdA, which was correlated with activation of caspase-3 and high molecular weight DNA fragmentation, two markers of apoptosis. Taken together, these observations indicate that in B-CLL cells CdA inhibits unscheduled DNA synthesis which represents the polymerizing step of a repair process responsive to DNA aggression. Inhibition of this process by CdA, together with a combined activation of the apoptotic proteolytic cascade by CdA and UV, may explain their synergistic cytotoxicity.

Alkylating Agents↗
PubMed2001

Second primary tumors and immune phenomena after fludarabine or 2-chloro-2'-deoxyadenosine treatment.

The purine nucleoside analogs fludarabine and 2-chloro-2'-deoxyadenosine display substantial activity in the treatment of various chronic lymphoproliferative disorders. Their major toxicities are primarily immunosuppression and myelosuppression. The profound influence of these drugs on the immune system has raised questions as to the emergence of secondary neoplasms or auto-immune disorders after their use. Based on a literature review and on personal observations, this article reviews the potential clinical importance of these concerns.

Antineoplastic Agents↗
PubMed2001

Resistance to 2-chloro-2'-deoxyadenosine of the human B-cell leukemia cell line EHEB.

The effects of 2-chloro-2'-deoxyadenosine (CdA, cladribine), an adenosine deaminase-resistant analogue toxic for both proliferating and resting lymphoid cells, were investigated in the human leukemia cell line EHEB, which was derived from a patient with B-cell chronic lymphocytic leukemia. These cells were found to be less sensitive to CdA than B-cell chronic lymphocytic leukemia lymphocytes (approximately 25-fold) and other human lymphoblastic cell lines (10-1000-fold). Phosphorylation of CdA by deoxycytidine kinase and intracellular accumulation of 2-chloro-2'-deoxyadenosine triphosphate (CdATP) were similar in EHEB cells and in other CdA-sensitive cell lines. In contrast, the inhibitory effect of CdA on ribonucleotide reductase activity, which was investigated in situ by the conversion of cytidine into deoxyribonucleotides and its incorporation into DNA, was much less pronounced in EHEB cells than in other human lymphoblastic cells. Accordingly, concentrations of deoxynucleoside triphosphates did not decrease and even tended to rise. Unexpectedly, incorporation of thymidine and deoxycytidine into DNA was increased severalfold after a 24-h incubation with CdA. CdA also increased the activities of deoxycytidine kinase and thymidine kinase approximately 4-fold. Analysis of the cell cycle by flow cytometry showed that after 24 h, CdA provoked an increase in the proportion of cells in S phase, synthesizing DNA. We conclude that the EHEB cell line is resistant to the cytotoxic action of CdA not only because of a lack of inhibition of ribonucleotide reduction but also because CdA, in contrast with its known effects, provokes in this cell line an increase in the proportion of cells replicating their DNA. Unraveling of the mechanism of this effect may shed light on clinical resistance to CdA.

Antineoplastic Agents↗
PubMed2000

Metabolism and cytotoxic effects of 2-chloroadenine, the major catabolite of 2-chloro-2'-deoxyadenosine.

EHEB cells, a continuous cell line derived from a patient with B cell chronic lymphocytic leukemia (B-CLL), synthesized, when incubated with tritiated 2-chloro-2'-deoxyadenosine (CdA), labeled mono-, di-, and triphosphate ribonucleosides at a much higher rate than CdA deoxyribonucleotides. Further analysis revealed that these ribonucleotides were formed from labeled 2-chloroadenine (CAde), which contaminated commercial tritiated CdA at a proportion of 2-3%. Since CAde is the major catabolite of CdA measured in plasma after oral or intravenous administration of CdA to patients, its metabolism and in particular its potential cytotoxicity were investigated both in EHEB cells and in B-CLL lymphocytes. Phosphorylation of CAde was inhibited by adenine, indicating that its initial metabolism most probably proceeds via adenine phosphoribosyltransferase (EC 2.4.2.7). In both cell types, chloro-ATP was the major metabolite formed from CAde and its concentration increased proportionally at least up to 50 microM CAde. At high concentration, CAde metabolism was accompanied by a decrease in intracellular ATP. Cytotoxicity of CAde, evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, showed an IC(50) of 16 microM in EHEB cells and 5 microM in B-CLL lymphocytes. At cytotoxic concentrations, apopain/caspase-3 activation and high molecular weight DNA fragmentation were observed, indicating that CAde cytotoxicity results from induction of apoptosis. However, since CAde cytotoxicity requires higher concentrations than CdA, it probably does not play a role in the therapeutic effect of CdA in the treatment of hematologic malignancies.

Adenine↗
PubMed2000

Phase I/II study of 2-chloro-2'-deoxyadenosine with cyclophosphamide in patients with pretreated B cell chronic lymphocytic leukemia and indolent non-Hodgkin's lymphoma.

Because of their substantial in vitro synergy, we conducted a dose-escalation study of cyclophosphamide (CP) added to 2-chloro-2'-deoxyadenosine (CdA) in patients with previously treated chronic lymphocytic leukemia and non-Hodgkin's lymphoma. CdA was given at a fixed dose (5.6 mg/m2/day) as a 2-h intravenous (i.v.) infusion, immediately followed by a 1-h i.v. infusion of CP, for 3 days. The initial daily CP dose was 200 mg/m2, and was escalated by 100 mg/m2 increments in successive cohorts of three to six patients to determine the maximum-tolerated dose (MTD). Additional patients were included at the MTD to extend toxicity and response analysis. Twenty-six patients received 68 cycles of chemotherapy. The MTD of CP after CdA 5.6 mg/m2, was 300 mg/m2. Acute neutropenia was the dose-limiting toxicity of this regimen, which was otherwise well tolerated. Delivery of repeated cycles was not feasible in eight patients (31%) because of prolonged thrombocytopenia. Severe infections were seen in three of 68 cycles (4%). The overall response rate was 58% (15 of 26; 95% CI, 36-76%), with 15% complete responses and 42% partial responses. These data show the feasibility of the association of CdA with CP. Given the response rate observed, further studies of this regimen are warranted in untreated patients, in particular with chronic lymphocytic leukemia and with Waldenström macroglobulinemia.

Adult↗
PubMed2000

Inhibition of RNA transcription: a biochemical mechanism of action against chronic lymphocytic leukemia cells by fludarabine.

Fludarabine is a nucleotide analog effective in the clinical treatment of chronic lymphocytic leukemia (CLL) and other indolent lymphocytic malignancies. Although the incorporation of fludarabine into DNA is a key event in causing cytotoxicity in proliferating leukemia cells, the precise mechanisms by which fludarabine kills CLL cells remain unclear because of the quiescent nature of this malignancy. The present study demonstrated that inhibition of RNA transcription correlated significantly with the cytotoxic action of fludarabine in CLL cells. In contrast, suppression of the low level of DNA synthesis did not affect the survival of the leukemia cells. In addition, inhibition of fludarabine incorporation into cellular DNA through repair synthesis in CLL cells did not alter the cytotoxicity of this drug. Rather, inhibition of RNA synthesis by fludarabine led to a specific diminishment of certain cellular proteins from CLL cells. The combination of fludarabine with another RNA synthesis inhibitor, actinomycin D, or with the protein synthesis inhibitor, puromycin, substantially enhanced the cytotoxic activity against CLL cells. These results suggest that termination of mRNA transcription and the consequent depletion of proteins required for cell survival may be a novel biochemical mechanism of action of fludarabine in CLL cells. Thus, inhibition of RNA/protein synthesis may provide a new therapeutic strategy for the treatment of CLL patients.

Antineoplastic Agents↗
PubMed2000

A phase I and pharmacokinetic study of docetaxel administered in combination with continuous intravenous infusion of 5-fluorouracil in patients with advanced solid tumors.

Encouraged by preclinical synergism between docetaxel and 5-fluorouracil (5FU), we conducted a Phase I study of docetaxel in combination with continuous i.v. infusion of 5FU in patients with advanced solid tumors to determine the maximum tolerated dose, the recommended dose for Phase II studies, and the safety and pharmacokinetic profiles of this combination. Forty-two patients with advanced solid tumors, most of whom had been previously treated, received docetaxel on day 1 as a 1-h i.v. infusion, immediately followed by a 5-day continuous i.v. infusion of 5FU, every 3 weeks without hematopoietic growth factor support. All patients were premedicated with methylprednisolone. Dose levels of docetaxel/SFU studied were (daily dose, in mg/m2) 60/300, 75/300, 75/500, 75/750, 85/750, 85/1000, and 75/1000. Forty-one patients were assessable for toxicity. The maximum tolerated dose determined during the first cycle was 1000 mg/m2/day for 5 days of 5FU with either 75 or 85 mg/m2 docetaxel. Dose-limiting toxicities at these dose levels were reversible secretory diarrhea (4 of 12 evaluable patients), stomatitis (2 patients), and febrile neutropenia (2 patients). Overall, grade 3/4 neutropenia and febrile neutropenia were seen in 63.4% and 9.8% of the patients, respectively. Four patients experienced grade 3/4 infection, which led to toxic death in one of them. There were five early deaths: (a) one was clearly treatment related; (b) two others were possibly treatment related or remotely treatment related; and (c) two deaths were not related to the study drugs. Partial responses were documented in 5 of 39 evaluable patients. Pharmacokinetic results of both drugs were consistent with those from single-agent studies. The recommended dose of this combination, which showed acceptable toxicity and antitumoral activity at various dose levels, is 85 mg/m2 docetaxel given as a 1-h i.v. infusion on day 1 immediately followed by a 5-day continuous i.v. infusion of 5FU (750 mg/m2/day). This study has been extended by adding cisplatin on day 1 of the combination of docetaxel and 5FU.

Adult↗
PubMed1999

Digital clubbing in a patient with progressive mantle cell lymphoma.

Digital clubbing with or without hypertrophic osteoarthropathy may occur in a variety of neoplastic diseases. We present the first description of digital clubbing in a patient with progressive mantle cell lymphoma, in the absence of any other apparent etiology. We suggest that clubbing might be a paraneoplastic manifestation in mantle cell lymphoma. The literature on digital clubbing in hematological neoplasms is reviewed.

Diagnosis, Differential↗
PubMed1999

Potentiation of antitumor effects of cyclophosphamide derivatives in B-chronic lymphocytic leukemia cells by 2-chloro-2'-deoxyadenosine.

Because 2-chloro-2'-deoxyadenosine (CdA) is active in B-chronic lymphocytic leukemia (B-CLL), and may interfere with DNA repair, we investigated the potentiating effect of CdA on the cytotoxicity induced in vitro in B-CLL lymphocytes by cyclophosphamide (CP) derivatives, which induce DNA damage by DNA cross-linking. Exposure to CdA at clinically achievable concentrations for 2 h, followed by mafosfamide (MAF) or 4-hydroxycyclophosphamide (4HC) for 22 h, resulted in synergistic cytotoxicity in the majority of B-CLL samples tested. Synergy between CdA and MAF was observed in cell samples of sensitive/untreated patients, as well as in cells of resistant/pretreated patients, particularly at the highest concentrations of MAF. In the cells treated with CdA and MAF, we observed loss in ATP and hallmarks of apoptosis, as evidenced by cellular morphology and high molecular weight DNA fragmentation. The synergy could be explained neither by an influence of MAF on the phosphorylation of CdA, nor by an increase in the incorporation of CdA into DNA in the presence of MAF. The in vitro synergy between CdA and CP derivatives provides a rationale for the use of this association in B-CLL patients.

Antineoplastic Agents, Alkylating↗
PubMed1999

Myelodysplastic syndrome with monosomy 5 and/or 7 following therapy with 2-chloro-2'-deoxyadenosine.

A few cases of secondary neoplasms occurring after treatment with 2-chloro-2'-deoxyadenosine (2CdA) have been reported, mostly in patients previously exposed to other anti-cancer drugs including alkylating agents (AA). Here we report on the occurrence of a myelodysplastic syndrome (MDS) with monosomy 5 and/or 7 in two patients after 2CdA treatment, without or prior to other toxic exposure. In light of a literature review and given the involvement of chromosomes frequently abnormal in secondary leukaemias, we suggest that 2CdA may induce therapy-related MDS (t-MDS).

Adult↗
PubMed1998

2-Chlorodeoxyadenosine with or without daunorubicin in relapsed or refractory acute myeloid leukemia.

2-Chlorodeoxyadenosine (2-CdA) is a purine analogue which has proved to be active in acute myeloid leukemia (AML), especially in children. In adults, results yielded by 2-CdA alone or with ara-C were less encouraging. Here we report on the efficacy of 2-CdA with or without daunorubicin (DNR) in 19 relapsing or refractory adult AML patients, with a median age of 57 years. 2-CdA was administered as a continuous infusion to all patients at a dose of 0.1 mg/kg per day for 7 days. For 14 patients, DNR was added at a dose of 50 mg/m2 per day on days 5, 6, and 7. Antileukemic activity was observed in all the patients, but no single complete remission was achieved. One patient had a long-lasting partial response (response rate=5%). The remaining patients died of progressive AML (n=7), uncontrollable infection with persistent disease (n=10), and cerebral hemorrhage (n=1). Median survival from start of 2-CdA therapy was 56 days. Long-lasting neutropenia and transfusion-dependent thrombopenia were encountered in all 16 evaluable patients. Grade 4 hepatic toxicity occurred in one patient. Other side effects included nausea in six, mucositis in three, and mental disturbances in three patients. Compared with 2-CdA alone, the addition of DNR to 2-CdA changed neither the response rate nor the toxicities. In conclusion, our data do not support the use of 2-CdA +/- DNR for relapsing or refractory adult AML patients, at least as used in the present regimen.

Adolescent↗
PubMed1996

Infectious complications after 2-chlorodeoxyadenosine therapy.

Infection is a common adverse event after therapy with nucleoside analogs, including 2-chlorodeoxyadenosine (CdA). However, the incidence of CdA-related infections has been poorly documented. In this study we compare, in the same patient population, the incidence of infectious episodes during the 6-month period before CdA to their incidence during the 6 months after initiating therapy. Ninety-five patients with hematological malignancies were studied. The incidence of infectious episodes almost doubled after CdA (0.87 vs. 0.47 during the pre-CdA period). The following factors were associated with an increased risk of infection after therapy: a history of previous chemotherapy, infection during the pre-CdA period and a diagnosis of chronic lymphocytic leukemia or of non-Hodgkin's lymphoma. Age, neutrophil and lymphocyte count at onset of CdA and time interval between diagnosis and therapy with CdA did not correlate with the infectious risk. The pattern of infections was modified after therapy with an increase of herpes virus infections ( 1 vs. 8 episodes, p=0.04) and of fever of unknown origin (6 vs. 17 episodes, p=0.03). In conclusion, a population at high risk for developing infectious complications after CdA therapy can be identified. Specific measures aimed at reducing the incidence of infectious events should concentrate on this population.

Adult↗
PubMed1996

Limited activity of mini-dose interferon alpha-2a in the treatment of myelodysplastic syndrome.

Impairment in marrow function often characterizes the evolution of myelodysplastic syndrome. As a differentiating agent, interferon alpha 2a (INF alpha) has been shown to be active in the correction of cytopenias related to myelodysplastic syndromes (MDS). We report the clinical course of 9 patients with MDS treated with low-dose subcutaneous INF alpha (1 x 10(6), 3 times per week). A significant effect on anemia was only demonstrated in one patient (11%). In the other, eight, therapy was totally ineffective and four of them could not receive the complete treatment due to worsening cytopenias or leukemic transformation. In conclusion, in our study, INF alpha had only limited activity in the treatment of myelodysplastic syndrome.

Drug Evaluation↗
PubMed1995

Cyclosporin A in the treatment of refractory B chronic lymphocytic leukemia (B-CLL).

Partial tumoral responses have been described after cyclosporin A treatment in refractory B-chronic lymphocytic leukemia patients. We report the effect of this therapy in five patients prospectively treated with oral conventional dose of cyclosporin A. Antitumoral efficiency was marginal (one sustained partial response among five patients) which, added to a potential worsening of natural and therapy-related immunodepression, limits its use in this instance.

Adult↗
PubMedDate not supplied

Donor cell leukemia developing after hematopoietic stem cell transplantation for multiple myeloma.

The development of secondary leukemia in donor cells after allogeneic stem cell transplantation is a rare event. We describe the occurrence of acute myeloid leukemia in donor cells 4 years after a stem cell transplantation for multiple myeloma. The multiple myeloma was relapsing at the time of the onset of acute myeloid leukemia. Secondary leukemia in donor cells after transplantation for multiple myeloma has not yet been reported.

Adult↗