Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cladribine is an effective therapy for hairy cell leukaemia (HCL), but the standard regime is frequently complicated by neutropenic fever and prolonged T-cell depression. We studied 102 patients with active HCL following treatment with various doses of cladribine given for 7 d. Two patients received 1 mg cladribine/m2/d without toxicity or effect. Eight subsequent patients received 2 mg cladribine/m2/d, and normalized cytopenia as quickly as 94 control patients receiving a standard dose (3.4 mg/m2 or 0.085 mg/kg), with significantly less lymphopenia and a similar complete remission rate.
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PMID:Low-dose cladribine for symptomatic hairy cell leukaemia. 773 67

2-Chlorodeoxyadenosine (2-CdA) has recently established itself as an extremely effective therapy for patients with hairy cell leukemia. To date, the issue of how to treat patients relapsing after 2-CdA has not been adequately addressed. In our initial study, 41 of 46 patients achieved an objective response (complete or partial remission). The only persistent toxicity associated with this agent appears to be significant suppression of CD4+ lymphocyte counts, albeit without evidence of clinical sequelae at a median follow-up of 30 months (range, 7-43). Eight patients have developed recurrent disease 3-23 months (median, 16 months) after 2-CdA. Because of progressive cytopenias, three of these patients were treated with interferon-alpha (IFN-alpha) (3 x 10(6) units subcutaneously three times per week), commencing 2, 9 and 16 months after the documentation of relapse. All three patients have shown an objective response with reduction of marrow hairy cells and amelioration of neutropenia and thrombocytopenia (two patients, complete remission; one patient, partial remission). Responses were maintained while on IFN-alpha, but two patients relapsed shortly (3 and 4 months, respectively) after discontinuation of IFN. There was no significant toxicity. Prior to commencing IFN-alpha, 22-36 months after 2-CdA, these patients' absolute CD4+ counts were suppressed (mean 211/microliters, s.d. +/- 85/microliters), but have not significantly changed after 10, 11 and 18 months of IFN-alpha therapy (mean 225/microliters, s.d. +/- 93/microliters). These results suggest that in hairy cell leukemia patients relapsing after 2-CdA, IFN-alpha may be a reasonable therapeutic option, especially if persistent CD4+ lymphocytopenia is present.
Leukemia 1995 May
PMID:Response to interferon-alpha in patients with hairy cell leukemia relapsing after treatment with 2-chlorodeoxyadenosine. 776 59

Serial bone-marrow biopsies were obtained from 46 hairy cell leukaemia (HCL) patients at different time intervals during the course of their disease. The patients were treated according to the following schemes: 14 received alpha-lymphoblastoid interferon (alpha-IFN), 11 2-Chlorodeoxyadenosine (2CdA), and 21 alpha-IFN first, followed by 2CdA. All the biopsies were studied by immunohistochemical means for the detection of minimal residual disease. The administration of 2CdA produced the highest reduction of both the tumor burden and HC index, with residual hairy cells (HCs) being undetectable at conventional light microscopy in most cases. In addition, 2CdA induced a higher degree of hypocellularity than alpha-IFN: the reduction in the amount of normal bone-marrow, however, was less pronounced in patients who had alpha-IFN before 2CdA. Of 9 patients who received both alpha-IFN and 2CdA and were followed for more than 2 years, 3 relapsed, while the remaining 6 continued to show rare HCs 2 years after 2CdA administration.
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PMID:Bone-marrow biopsy in hairy cell leukaemia (HCL) patients. Histological and immunohistological analysis of 46 cases treated with different therapies. 782 56

We have previously reported that the chain-terminating nucleoside analogue 2',3'-dideoxyadenosine (ddA) is specifically cytotoxic for TdT-positive cells in the co-presence of the adenosine deaminase (ADA) inhibitor coformycin (CF). Further studies with ddA/CF revealed that cytotoxicity occurs only if ddA is supplied from the Calbiochem or Fluka companies. ddA supplied from other commercial sources (Pharmacia, Sigma) or the NCI Pharmaceutical Resources Branch is non-cytotoxic. To explore the basis for this difference, ddA from various sources was subjected to reverse-phase high-pressure liquid chromatography (HPLC) analysis. The Calbiochem and Fluka ddA had a unique HPLC peak, with a retention time of 12.8 min, representing a contaminant of less than 0.1% of the bulk material applied to the C-18 HPLC column. Study of all HPLC peaks resolved from the bulk material showed cytotoxic activity in only the 12.8 min peak. To identify the nature of the unknown compound, we compared HPLC characteristics of the synthetic intermediates and byproducts of ddA synthesis to the peak eluting at 12.8 min. Of these, only 3'-deoxyadenosine (cordycepin) had similar HPLC characteristics. In addition, in the co-presence of CF, cordycepin was specifically cytotoxic (IC50 < 0.5 microM) for all TdT-positive cell lines tested. Cytotoxicity was seen in TdT-negative cells only at concentrations 10-100-fold higher. We conclude that our previous report on ddA/CF as a TdT-specific cytotoxic combination was due to contamination of the ddA supplied by Calbiochem by cordycepin. ddA itself is non-cytotoxic for TdT-positive cells. Cordycepin in the co-presence of an ADA inhibitor may be effective in the treatment of TdT-positive hematological malignancies.
Leukemia 1995 Jan
PMID:2',3'-Dideoxyadenosine killing of TdT-positive cells is due to a trace contaminant. 784 29

Cladribine is a synthetic purine nucleoside with demonstrated activity in hairy cell leukemia and acute myeloid leukemia. We have studied the pharmacokinetics of this drug in 25 pediatric patients with acute leukemia treated with cladribine as a single agent, 8.9 mg/m2/24 h, for 5 days by continuous i.v. infusion. Twelve patients were in relapse, and acute myeloid leukemia was newly diagnosed in 13 patients. Plasma, urine, and cerebrospinal fluid cladribine concentrations were determined by a radioimmunoassay with a limit of detection of 1 nM. An open two-compartment model was fit to the plasma concentration data. The mean (SD) clearance was 39.4 (12.4) liters/h/m2 and ranged from 14.4-55.4 liters/h/m2. When clearance was normalized to body weight (liters/h/kg) it was negatively correlated with age, with older patients having slower clearances per unit of body weight. However, when clearance was normalized to body surface area, no significant correlation with age was observed. The mean (SD) steady-state plasma concentration (predicted 120-h concentration) was 37.7 (17.3) nM and ranged from 23.2-84.5 nM. The terminal phase half-life in 22 patients ranged from 14.3-25.8 h, with a mean (SD) of 19.7 (3.4) h. The volume of distribution at steady state was highly variable, with a mean (SD) of 356.6 (225.2) liters/m2. None of these parameters was significantly different between patients in relapse and patients with newly diagnosed disease. Renal clearance was determined in 7 patients and ranged from 34.6-643.6 ml/min/m2, with a mean (SD) of 317.9 (208.7) ml/min/m2. Renal clearance as a percentage of total systemic clearance ranged from 11.0-85.1%, with a mean of 51.0%. In 11 patients, the mean (SD) cerebrospinal fluid concentration was 6.1 (3.97) nM, a mean of 18.2% of the steady-state plasma concentration. The CSF:plasma concentration ratio was significantly higher on day 5 (22.7% in 7 patients) than on day 4 (7.6% in 3 patients; P = 0.03). Additional studies are needed to further define the metabolic fate of cladribine. In this paper we provide the first comprehensive description of the pharmacokinetics of this drug in children and provide data which suggest that cladribine may be useful in the treatment of patients with meningeal leukemia or malignancies of the central nervous system.
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PMID:Pharmacokinetics of cladribine (2-chlorodeoxyadenosine) in children with acute leukemia. 790 99

We used a recently established stroma-supported tissue culture technique that allows long-term culture of acute lymphoblastic leukemia (ALL) cells to study 2-chloro-2'-deoxyadenosine (2CdA) cytotoxicity to leukemic lymphoblasts. In the 20 cases of ALL studied, the number of cells recovered after 7 days of culture on allogeneic stromal layers were 58-192% (median, 95.5%) of those originally seeded. In parallel cultures with 2CdA (100 nM), 74- > 99% (median, 97.5%) of leukemic lymphoblasts were killed. The cytotoxicity of 2CdA extended to all ten samples with either the t(9;22) (q34;q11) or 11q23 chromosomal abnormalities, karyotypes associated with an extremely poor outcome, as well as to two samples collected at the time of relapse. The effects of 2CdA were dose-dependent, and were due to triggering of apoptosis as shown by typical morphologic changes and occurrence of DNA fragmentation. Stromal layers were apparently not affected by 2CdA treatment, even when used at 1000 nM. We also tested 2CdA cytotoxicity to multidrug resistant subclones of the CCRF-CEM ALL cell line. CEM/VLB100 expresses P-glycoprotein, whereas CEM/VM-1 and CEM/VM-1-5 have topoisomerase II mutations that are associated with resistance to topoisomerase II inhibitors. Overexpression of P-glycoprotein or alterations in topoisomerase II did not protect cells from 2CdA cytotoxicity. We conclude that 2CdA is cytotoxic in most cases of ALL. The method used in this study may be applied to evaluate leukemic blast cell sensitivity to compounds with potential anti-leukemic activity, and to select patients for entry into clinical trials.
Leukemia 1994 Jul
PMID:Use of stroma-supported cultures of leukemic cells to assess antileukemic drugs. II. Potent cytotoxicity of 2-chloro-deoxyadenosine in acute lymphoblastic leukemia. 791 12

Hairy cell leukaemia is a rare chronic lymphoproliferative disease, characterized by splenomegaly, pancytopenia and recurrent infection. The characteristic 'hairy cells', present in the peripheral blood and bone marrow, are the hallmark of this leukaemia. The disease has a chronic, progressive course, and the majority of patients afflicted by it require therapy. The most common reason to initiate treatment is neutropenia with or without associated infectious complications, or the development of severe thrombocytopenia. Therapeutic options in hairy cell leukaemia include splenectomy, interferon administration, or the use of chemotherapeutic agents such as pentostatin (2'-deoxycoformycin) and 2-chlorodeoxyadenosine. Splenectomy is still indicated in the treatment of young patients with significant splenomegaly and only minimal bone marrow involvement. Interferon treatment induces remission in approximately 90% of patients with hairy cell leukaemia, but complete remission is obtained in only 5-10%. The development of antibodies against interferon was initially considered a major problem, but longer follow-up of patients who developed antibodies has shown that it is transient and does not have a significant impact on the overall response to treatment. Pentostatin induces complete remission in 60-70% of patients and partial remission in 20-40%. 2-Chlorodeoxyadenosine is a very promising drug in the treatment of this rare leukaemia, inducing long-lasting complete remission in approximately 80% of patients. While interferon does not cure the disease, it is possible that a subset of patients treated with pentostatin or 2-chlorodeoxyadenosine are cured. Longer follow-up of these patients will determine whether this is true.
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PMID:Hairy cell leukaemia. 791 37

Patients with hairy cell leukemia (HCL) are susceptible to opportunistic intracellular infections, suggesting defects in cellular immunity. Prior studies have indicated an association between failure of IFN-alpha generation by peripheral blood mononuclear cells (MNC) and susceptibility to such infections. We here present results on IFN-alpha generation in HCL patients pre- and post-therapy. Prior to treatment with 2-chloro-2'-deoxyadenosine (CdA), MNC from 24 HCL patients with active disease produced little or not IFN-alpha (geometric mean < 40 IU/ml) compared with controls (n = 140, geometric mean 1730 IU/ml, p < 0.0005). After treatment with CdA, IFN-alpha generation was studied in 16 patients, with a geometric mean value of 650 IU/ml (p < 0.0005 compared with pre-CdA levels). The severe depression of IFN-alpha generation improved progressively following CdA therapy-induced clinical remission. We propose that deficiency of IFN-alpha production may play a role in the susceptibility to intracellular infections of patients with active HCL.
Leukemia 1994 Sep
PMID:Impaired interferon alpha response in hairy cell leukemia is corrected by therapy with 2-chloro-2'-deoxyadenosine: implications for susceptibility to opportunistic infections. 791 89

The semiautomated fluorometric microculture cytotoxicity assay (FMCA), based on the measurement of fluorescence generated from cellular hydrolysis of fluorescein diacetate (FDA) to fluorescein in microtiter plates, was used for in vitro evaluation of Cladribine (2-chlorodeoxyadenosine, CdA) interactions with five standard antileukemic drugs: amsacrine (Am), etoposide (VP16), daunorubicin (Dnr), cytosine arabinoside (AraC), and mitoxantrone (Mit). Samples from 31 patients with acute myelocytic leukemia (AML) were tested with continuous drug exposure. A large heterogeneity with respect to cell kill was observed for all combinations tested. An additive model provided a significantly better fit of the data compared to the effect of the most active single agent of the combination (Dmax) only for CdA+AraC. When the frequency of additive and synergistic interactions were calculated according to the multiplicative concept for drug interactions, the highest frequencies were observed for CdA+AraC and CdA+Dnr. This interaction pattern was confirmed by isobologram analysis. Cross-resistance analysis revealed high correlations between CdA and AraC whereas the correlations were weaker between CdA and the other drugs. The highest frequency of synergistic interactions was obtained for AraC+CdA, despite their cross-resistance. Of the non-cross-resistant drugs tested, Dnr appears to be the most effective adjunct to CdA in terms of interactions at the cellular level.
Leukemia 1994 Oct
PMID:Interactions between cladribine (2-chlorodeoxyadenosine) and standard antileukemic drugs in primary cultures of human tumor cells from patients with acute myelocytic leukemia. 793 68

2-Chlorodeoxyadenosine (CdA) is a deaminase-resistant purine analogue which has shown clinical activity against various haematological tumours, and is currently undergoing phase II trials. In the present study, the semiautomated fluorometric microculture cytotoxicity assay (FMCA) was used for in vitro evaluation of CdA activity in cell suspensions from both haematological and solid tumours. A total of 133 samples from various diagnoses were successfully tested with continuous drug exposure. CdA showed high in vitro activity against samples from chronic and acute lymphocytic leukaemia and acute myelocytic leukaemia, but little or no response was observed in the solid tumour groups. Cross-resistance analysis with standard drugs revealed the following rank order of correlation coefficients: cytosine arabinoside (AraC) > daunorubicin > doxorubicin > vincristine > prednisolone > 4-hydroperoxycyclophosphamide > etoposide > cisplatin. The high correlation between CdA and AraC was maintained even if the analysis was based only on the haematological tumours. The results indicate that CdA is differentially active against haematological tumours with little or no activity against solid tumours. CdA also appears highly cross resistant with AraC. If this disease-specific information is substantiated in further clinical trials and extended to other phase I-II drugs, non-clonogenic drug resistance assays such as the FMCA may become useful in new drug evaluation, and in targeting specific diagnoses and patients for phase II trials.
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PMID:In vitro activity of 2-chlorodeoxyadenosine (CdA) in primary cultures of human haematological and solid tumours. 794 67


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