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F-18-clofarabine, a nucleotide purine analog, is a substrate for deoxycytidine kinase (dCK), a key enzyme in the deoxyribonucleoside salvage pathway. F-18-clofarabine might be used to measure dCK expression and thus serve as a pre...
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F-18-clofarabine, a nucleotide purine analog, is a substrate for deoxycytidine kinase (dCK), a key enzyme in the deoxyribonucleoside salvage pathway. F-18-clofarabine might be used to measure dCK expression and thus serve as a predictive biomarker for tumor responses to dCK-dependent prodrugs or small-molecule dCK inhibitors, respectively. As a prerequisite for clinical translation, we determined the human whole-body and organ dosimetry of F-18-clofarabine. Methods: Five healthy volunteers were injected intravenously with 232.4 +/- 1.5 MBq of F-18-clofarabine. Immediately after tracer injection, a dynamic scan of the entire chest was acquired for 30 min. This was followed by 3 static whole-body scans at 45, 90, and 135 min after tracer injection. Regions of interest were drawn around multiple organs on the CT scan and copied to the PET scans. Organ activity was determined and absorbed dose was estimated with OLINDA/EXM software. Results: The urinary bladder (critical organ), liver, kidney, and spleen exhibited the highest uptake. For an activity of 250 MBq, the absorbed doses in the bladder, liver, kidney, and spleen were 58.5, 6.6, 6.3, and 4.3 mGy, respectively. The average effective dose coefficient was 5.1 mSv. Conclusion: Our results hint that F-18-clofarabine can be used safely in humans to measure tissue dCK expression. Future studies will determine whether F-18-clofarabine may serve as a predictive biomarker for responses to dCK-dependent prodrugs or small-molecule dCK inhibitors.
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Background Clofarabine is a nucleoside analogue with activity in children with acute lymphoblastic leukemia (ALL). Based on the hypothesis that clofarabine inhibits DNA repair after exposure to DNA-damaging agents, we designed a p...
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Background Clofarabine is a nucleoside analogue with activity in children with acute lymphoblastic leukemia (ALL). Based on the hypothesis that clofarabine inhibits DNA repair after exposure to DNA-damaging agents, we designed a phase I and extension study to evaluate the combination of clofarabine and cyclophosphamide in adult patients with relapsed/refractory ALL. Methods The continual reassessment method (CRM) was used to define the maximum tolerated dose (MTD). Results Fifty patients with a median age of 30 years (range, 21-72 years) were enrolled, 30 of whom were part of the phase I group. Clofarabine 40 mg/m2 intravenously daily × 3 days and cyclophosphamide 200 mg/m2 intravenously every 12 hours × 3 days were established as the MTDs. Dose limiting toxicity (DLT) included diarrhea, transaminase elevations, and skin rashes. The response rate of the whole study group was 14%, including 10% of patients who achieved complete remission (CR) or CR without platelet recovery (CRp). Three responses occurred in patients with primary refractory disease. Early mortality (< 30 days) was 6%. The median duration of response was 69 days (range, 5-315 days). Median overall survival was about 3 months. Compared with day 1 (cyclophosphamide alone), H2AX phosphorylation was increased on day 2 when clofarabine and cyclophosphamide were administered as a couplet (n = 8). Conclusion The combination of clofarabine plus cyclophosphamide at the doses used in this study in a group of heavily pretreated patients with ALL is only moderately effective. Other doses, alternative schedules, or a more favorable patient population may achieve better results.
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Relapse after allogeneic hematopoietic stem cell transplantation (alloHSCT) remains one of the leading causes of mortality in patients with leukemia. Treatment options in this population remain limited, with concern for both incre...
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Relapse after allogeneic hematopoietic stem cell transplantation (alloHSCT) remains one of the leading causes of mortality in patients with leukemia. Treatment options in this population remain limited, with concern for both increased toxicity and further relapse. We treated 18 patients with acute leukemia for marrow +/- extramedullary relapse after a previous alloHSCT with a myeloablative cytoreductive regimen including clofarabine, melphalan, and thiotepa followed by a second or third transplantation from the same or a different donor. All patients were in remission at the time of the second or third transplantation. All evaluable patients engrafted. The most common toxicity was reversible transaminitis associated with clofarabine. Two patients died from transplantation-related causes. Seven patients relapsed after their second or third transplanation and died of disease. Nine of 18 patients are alive and disease free, with a 3-year 49% probability of overall survival (OS). Patients whose remission duration after initial alloHSCT was >6 months achieved superior outcomes (3-year OS, 74%, 95% confidence interval, 53% to 100%), compared with those relapsing within 6 months (0%) (P <.001). This new cytoreductive regimen has yielded promising results with acceptable toxicity for second or third transplantations in patients with high-risk acute leukemia who relapsed after a prior transplantation, using various graft and donor options. This approach merits further evaluation in collaborative group studies. (C) 2016 American Society for Blood and Marrow Transplantation.
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We investigated protracted low-dose oral Clofarabine for the treatment of myelodysplastic syndromes (MDS). Adults with an International Prognostic Scoring System (IPSS) score of INT-1 or higher who had failed first line therapy we...
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We investigated protracted low-dose oral Clofarabine for the treatment of myelodysplastic syndromes (MDS). Adults with an International Prognostic Scoring System (IPSS) score of INT-1 or higher who had failed first line therapy were eligible. INT-1 patients had to be transfusion-dependent. We started with oral Clofarabine at 5 mg (fixed dose) daily for 10 consecutive days on a 28-day cycle. Toxicity prompted a modification to 1 mg PO daily for 10 days and then 1 mg PO daily for 7 days. Patients received treatment indefinitely until loss of response or unacceptable toxicity. Nine patients (5 women) were enrolled and evaluable (median age 65 years; range 55-81). A 10-day regimen of oral Clofarabine at 5 mg/day induced Grade IV pancytopenia. A dose of 1 mg/day for 7128 days was very well tolerated without significant toxicity. Three patients had responses (2 with responses lasting up to 21 and 51 cycles) defined as stable disease in spite of no significant change on bone marrow evaluation. Low-dose oral Clofarabine (1 mg daily for 7128 days) proved both effective and safe for patients with MDS who had failed prior therapy. This patient population is particularly sensitive to more protracted Clofarabine treatment schedules. (C) 2015 Elsevier Ltd. All rights reserved.
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This experiment aims to develop and validate the RP-HPLC method for clofarabine in a bulk and pharmaceutical dosage form. Chromatographic separation was achieved on Inertsil ODS 3V (150x 4.6 mn) diameter column. The mobile phase c...
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This experiment aims to develop and validate the RP-HPLC method for clofarabine in a bulk and pharmaceutical dosage form. Chromatographic separation was achieved on Inertsil ODS 3V (150x 4.6 mn) diameter column. The mobile phase comprised of phosphate buffer (pH 4.0): methanol (40:60) at a flow rate of 1 mL min~-1 and all eluents were detected at 270 nm. The runtime was 10 minutes. Calibration curves at five levels for clofarabine were linear in the range of 10-30 ug mL~-1. Accuracy for clofarabine was studied in the range of 50-150 % quality control standard levels. A validated method was found to be accurate, reproducible, linear, precise, and robust.
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Pediatric patients with refractory multisystem Langerhans cell histiocytosis (LCH) have a poor prognosis despite aggressive chemotherapy. Salvage therapy with cytarabine and cladribine has shown promise as an effective treatment b...
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Pediatric patients with refractory multisystem Langerhans cell histiocytosis (LCH) have a poor prognosis despite aggressive chemotherapy. Salvage therapy with cytarabine and cladribine has shown promise as an effective treatment but is associated with significant toxicity. A previous report described two patients with refractory LCH who had a rapid response to single-agent clofarabine with minimal toxicity. In this report, we describe four children with refractory, risk-organ-positive LCH who were treated with clofarabine and provide follow-up for the two previously reported cases. The results support development of a formal trial evaluating clofarabine as front-line salvage for refractory LCH.
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Clofarabine triphosphate is an intracellular active metabolite of clofarabine. In the present study, we developed and validated a rapid, sensitive, and selective liquid chromatography-tandem mass spectrometry method (LC-MS/MS) for...
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Clofarabine triphosphate is an intracellular active metabolite of clofarabine. In the present study, we developed and validated a rapid, sensitive, and selective liquid chromatography-tandem mass spectrometry method (LC-MS/MS) for quantifying clofarabine triphosphate concentrations in human peripheral blood mononuclear cells (PBMCs). PBMCs were isolated from blood using the Ficoll gradient centrifugation method. Chromatographic separation was performed on a CN column using an isocratic mobile phase comprising acetonitrile/5 mM ammonium acetate with 0.001% ammonium hydroxide (20/80, v/v) at a flow rate of 0.60 mL/min. Detection was carried out by MS/MS in the multiple reaction monitoring mode using a negative electrospray ionization interface. The method was validated in concentration ranges of 1.25-100 ng/10(7) cells with acceptable accuracy and precision using 50 mu L of cell extract. Clofarabine triphosphate was stable in a series of stability studies with bench-top, auto-sampler, and repeated freeze-thaw cycles. The validated method was successfully used to measure the concentrations of clofarabine triphosphate in PBMCs from cancer patients treated with clofarabine (C) 2014 Elsevier B.V. All rights reserved.
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We conducted a phase I-II study of transplantation conditioning with clofarabine-melphalan-alemtuzumab for patients with advanced hematologic malignancies. Ten patients were accrued to the phase I portion, which utilized an accele...
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We conducted a phase I-II study of transplantation conditioning with clofarabine-melphalan-alemtuzumab for patients with advanced hematologic malignancies. Ten patients were accrued to the phase I portion, which utilized an accelerated titration design. No dose-limiting toxicity was observed, and clofarabine 40 mg/m 2 × 5, melphalan 140 mg/m 2 × 1, and alemtuzumab 20 mg × 5 was adopted for the phase II study, which accrued 72 patients. Median age was 54 years. There were 44 patients with acute myelogenous leukemia or myelodysplastic syndromes, 27 with non-Hodgkin lymphoma, and nine patients with other hematologic malignancies. The largest subgroup of 35 patients had American Society for Blood and Marrow Transplantation high-risk, active disease. All evaluable patients engrafted with a median time to neutrophil and platelet recovery of 10 and 18 days, respectively. The cumulative incidence of treatment-related mortality was 26% at 1 year. Cumulative incidence of relapse was 29% at 1 year. Overall survival was 80% (95% confidence interval [CI], 71-89) at 100 days and 59% (95% CI, 47-71) at 1 year. Progression-free-survival was 45% (95% CI, 33-67) at 1 year. Rapid-onset renal failure was the main toxicity in the phase II study and more frequent in older patients and those with baseline decrease in glomerular filtration rate. Grade 3-5 renal toxicity was observed in 16 of 74 patients (21%) treated at the phase II doses. Clofarabine-melphalan-alemtuzumab conditioning yields promising response and duration of response, but renal toxicity poses a considerable risk particularly in older patients.
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There is no commonly agreed-on therapeutic regimen for acute myeloid leukemia patients with a contraindication to receiving anthracyclines (eg, because of cardiac dysfunction or prior exposure to anthracyclines). Our study compare...
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There is no commonly agreed-on therapeutic regimen for acute myeloid leukemia patients with a contraindication to receiving anthracyclines (eg, because of cardiac dysfunction or prior exposure to anthracyclines). Our study compared 3 anthracycline-free regimens currently used in France. Despite the poor outcome of these patients, topotecan plus cytarabine is effective and safe in these patients.
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