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Biomedical subjects

E Estey

Publications and source records attributed to E Estey.

At least 127 records · Page 7Linked to original sources
PubMed1994

Lack of effect of 2-chlorodeoxyadenosine therapy in patients with chronic lymphocytic leukemia refractory to fludarabine therapy.

BACKGROUND: Fludarabine and 2-chlorodeoxyadenosine are nucleoside analogues that have proved effective in patients with chronic lymphocytic leukemia (CLL). Although their mechanism of action is thought to be similar, a small number of patients who do not respond to fludarabine do respond to 2-chlorodeoxyadenosine. The extent to which 2-chlorodeoxyadenosine is effective in patients who do not respond to fludarabine is not known, however. METHODS: We treated 28 patients with CLL refractory to fludarabine therapy with a continuous infusion of 2-chlorodeoxyadenosine at a daily dose of 4 mg per square meter of body-surface area for seven days. The treatment could be repeated monthly. The number of treatments ranged from one to five; patients who responded continued to receive treatment until the maximal response was achieved. RESULTS: Two patients (7 percent) had partial remissions, but no patients had complete remissions. One other patient had a substantial response but had residual thrombocytopenia. The rate of response in most affected organs was 20 percent, but anemia or thrombocytopenia rarely improved. Myelosuppression was frequent, and 65 percent of the courses of 2-chlorodeoxyadenosine therapy were accompanied by febrile episodes or infections. Ten patients died within 60 days of starting therapy with 2-chlorodeoxyadenosine; eight deaths were related to infection. The median platelet count at the start of 2-chlorodeoxyadenosine therapy in these 10 patients was 24,000 per cubic millimeter, as compared with 109,000 per cubic millimeter in the other 18 patients. Five patients were alive after a median follow-up of 24 months. CONCLUSIONS: Patients with advanced CLL refractory to fludarabine therapy are unlikely to benefit from treatment with 2-chlorodeoxyadenosine. Although 20 percent of the patients have some response, thrombocytopenia and anemia are rarely corrected and may be made worse by 2-chlorodeoxyadenosine therapy.

Adult↗
PubMed1994

What is the contribution of molecular studies to the diagnosis of BCR-ABL-positive disease in adult acute leukemia?

The detection of BCR-ABL transcripts by polymerase chain reaction and hybridization protection assay was investigated in 59 adults with acute leukemia in whom the Philadelphia chromosome (Ph) abnormality was not documented by cytogenetic analysis. These included 35 patients with acute lymphocytic leukemia (ALL) and 24 with acute myelogenous leukemia (AML). Overall, three patients were found to have Ph-related molecular abnormalities; one had p190 and two had p210 disease. All three patients had ALL and were among 16 patients with insufficient metaphases by cytogenetic analysis, yielding an incidence of 19% in the latter category. Based on a 32% incidence of insufficient metaphases in our adult ALL population, we project an additional detection rate of 6% Ph-positive ALL by molecular studies and an overall incidence of 20% (14% + 6%) Ph-positive or BCR-ABL-positive ALL. None of the remaining patients with ALL and none of the 24 patients with AML investigated had BCR-ABL-positive disease. We conclude that molecular studies are useful in detecting BCR-ABL-positive disease in a subset of patients with Ph-positive ALL who are not identified by cytogenetic analysis because of insufficient metaphases.

Acute Disease↗
PubMed1994

Primary therapy of Waldenström's macroglobulinemia with 2-chlorodeoxyadenosine.

PURPOSE: To assess the activity of 2-chlorodeoxyadenosine (2CdA) as primary therapy for patients with Waldenström's macroglobulinemia. PATIENTS AND METHODS: 2CdA was given to 26 consecutive, previously untreated and symptomatic patients with Waldenström's macroglobulinemia. Two courses were administered to outpatients at a dose of 0.1 mg/kg body weight per day for a 7-day continuous infusion using a portable pump through a central venous catheter. Responding patients were followed up without further therapy and were scheduled to receive two additional treatments with 2CdA on disease relapse. RESULTS: Twenty-two of 26 patients responded to the 2CdA therapy (85%; 95% confidence interval [CI], 65% to 96%), including three patients who achieved a complete response and 19 patients who had a partial response. Treatment was well tolerated, with no acute hematologic toxicity. A marked and sustained reduction of CD4+ lymphocytes occurred in all patients and may have contributed to a fatal infection with disseminated herpes simplex in one patient. With a median follow-up of 13 months, five patients have relapsed and all re-treated patients have responded again to 2CdA. CONCLUSION: 2CdA is highly active in previously untreated patients with Waldenström's macroglobulinemia. A limited program of treatment induced responses of good quality and long duration in more than 80% of patients.

Adult↗
PubMed1994

Use of granulocyte colony-stimulating factor before, during, and after fludarabine plus cytarabine induction therapy of newly diagnosed acute myelogenous leukemia or myelodysplastic syndromes: comparison with fludarabine plus cytarabine without granulocyte colony-stimulating factor.

PURPOSE: To determine whether granulocyte colony-stimulating factor (G-CSF) administered before, during, and after fludarabine plus cytarabine (ara-C; FA) chemotherapy affected complete response (CR) rate, infection rate, blood count recovery, or survival in patients with newly diagnosed acute myelogenous leukemia (AML) or myelodysplastic syndromes (MDS). PATIENTS AND METHODS: A total of 112 patients with newly diagnosed AML (n = 69) or MDS (n = 43) received G-CSF 400 micrograms/m2/d 1 day before (presenting WBC count < 50,000/microL) and/or during (all patients) fludarabine 30 mg/m2/d and ara-C 2 g/m2/d for 5 days (FLAG). G-CSF continued until a CR was achieved. Results were compared with those in 85 newly diagnosed patients (54 AML, 31 MDS) previously treated with FA without G-CSF. RESULTS: Patients in both groups were relatively old (median age of all patients, 63 years), and were likely to have prognostically unfavorable cytogenetic abnormalities (36% had abnormalities of chromosomes 5 and 7 [-5/-7]). G-CSF accelerated recovery to > or = 1,000 neutrophils (P < .0001; median, 34 days for FA, 21 days for FLAG), but logistic regression provided no evidence that the CR rate was higher with FLAG than with FA (P = .50), with unadjusted CR rates of 63% and 53%, respectively. This may reflect relatively high rates of death before neutrophil recovery in both groups. Rates of infection were similar in both groups. The follow-up duration in remission is short, and much of these data remain censored. To date, survival is similar with FA and FLAG. CONCLUSION: On average, G-CSF before, during, and after FA had no effect on CR or infection rates in this population, in which elderly patients and poor prognostic factors were prevalent. The use of FA and laminar airflow rooms rather than more usual therapy needs to be considered when analyzing the results.

Aged↗
PubMed1994

Clinical experience with fludarabine in leukaemia.

Fludarabine (Fludara) is a new purine analogue that was first entered into clinical trials in 1982. Results of initial studies with high dosages (> 96 mg/m2/day for 5 to 7 days) of fludarabine in acute leukaemia showed significant cytoreductive activity but a high incidence of severe irreversible neurotoxicity. The results of subsequent studies with lower dosages of 25 to 30 mg/m2/day for 5 days in chronic lymphocytic leukaemia (CLL) and low grade lymphomas have shown this regimen to be effective and safe, with almost no significant neurotoxicity. At present, the major role of fludarabine in leukaemia is in the management of CLL. In previously treated patients with CLL, responses are obtained in more than 50% of patients, with two-thirds of those responses being complete remissions according to the National Cancer Institute Working Group (NCIWG) criteria for complete response and partial response. The major causes of morbidity associated with fludarabine in CLL are infections and febrile episodes. These occur more frequently in previously treated patients and those with advanced stage of disease. Myelosuppression is dose limiting and a small proportion of patients with CLL develop moderate to severe and sometimes protracted myelosuppression. Administration of combined fludarabine and cytarabine (cytosine arabinoside; ara-C) alone (FA regimen) or together with granulocyte colony-stimulating factor (FLAG regimen) produced high response rates in previously treated refractory patients with acute leukaemia and previously untreated patients with acute myelogenous leukaemia or myelodysplastic syndrome. The wide range of biochemical and biological activities of fludarabine suggests that it will have an expanding role in future combinations in the treatment of both acute and chronic leukaemias.

Antineoplastic Agents↗
PubMed1994

Therapy-related leukemia and myelodysplastic syndrome in chronic lymphocytic leukemia.

A retrospective analysis was performed to determine the incidence and clinical features of acute myelogenous leukemia/myelodysplastic syndrome (AML/MDS) developing in chronic lymphocytic leukemia (CLL) patients. AML/MDS occurred in 3/1374 CLL patients seen at a single institution between 1972 and 1992. The median follow-up exceeded 7 years and 72% of these patients had received prior alkylating agent therapy. The expected number of AML/MDS developing in a general population of the same size was 1.2 as calculated from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program data (observed-to-expected ratio = 2.49; 95% confidence interval = 0.9-7.3; p = 0.12). Although, not included in the incidence calculation, four patients with CLL were referred at the time of development of AML/MDS. CLL and AML/MDS were diagnosed concurrently in two patients. Three of the patients had received no prior alkylating agents. The median survival was 17 months in patients who had received no prior treatment, and 5 months in those who had received prior chemotherapy. Our results suggest that patients with CLL in whom AML/MDS develops have similar prognoses to other patients with AML/MDS. Furthermore, this analysis does not provide evidence for a heightened risk of AML/MDS in CLL patients, despite treatment with known leukemogenic agents.

Aged↗
PubMed1994

Abnormalities in the long arm of chromosome 11 (11q) in patients with de novo and secondary acute myelogenous leukemias and myelodysplastic syndromes.

Leukemias with abnormalities in chromosome 11q23 occur frequently after exposure to topoisomerase II-reactive drugs. We investigated the characteristics and outcome of patients with de novo or secondary acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS) with abnormalities in chromosome 11q. Sixty-one patients had 11q abnormalities. Alterations involved 11q23 in 38 patients and other 11q abnormalities in 23. Sixteen patients had secondary disease, 12 involving 11q23, and four with other 11q abnormalities; 26 patients with de novo disease had 11q23 abnormalities and 19 other 11q abnormalities. The most common 11q23 abnormality was t(9;11), significantly more common in secondary (9/12) than in de novo (6/26) leukemias (p = 0.003). There were no significant differences in clinical characteristics between de novo and secondary groups involving 11q23. Five of 12 patients (42%) with secondary and 20/26 (77%) with de novo disease achieved complete remission (p = 0.05). Median survival was 6 weeks in the secondary group and 71 weeks in the de novo group (p = 0.001). There were no long-term survivors in either group. Results are similar when other 11q abnormalities are included. Adults with AML or MDS with 11q abnormalities secondary to prior chemotherapy have a worse prognosis than patients presenting de novo. However, 11q abnormalities define a population with a poor prognosis even when presenting de novo.

Adolescent↗
PubMed1994

Characteristics and outcome of patients with acute lymphocytic leukemia and myeloperoxidase-positive blasts by electron microscopy.

The purpose of the study was to analyze the clinical and laboratory characteristics of patients with acute lymphocytic leukemia (ALL) who exhibited myeloperoxidase-positive blasts by electron microscopy (EM-MPO-positive), and assess their response to therapy and their prognosis. Since 1988, 21 adults with newly-diagnosed ALL and EM-MPO-positive blasts were referred to our service. In addition to documentation of their clinical and hematopathologic characteristics, patients underwent cytogenetic, immunophenotypic, molecular, and electron-microscopic evaluations. Twenty patients were treated with the vincristine-Adriamycin-dexamethasone (VAD) regimen, and one patient was induced with amsacrine and high-dose cytosine arabinoside (ara-C). The 21 patients were among 141 patients with ALL (15%) seen during the same period. Their median age was 46 years (range 15 to 77 years). The immunophenotype was T-cell ALL in 12 patients (57%). Karyotypic studies did not demonstrate specific recurrent abnormalities. The median percentage of EM-MPO-positive blasts was 15% (range 3% to 45%). Eighteen patients (85%) had high-risk ALL. With induction chemotherapy 15 of 20 (75%) receiving VAD therapy achieved a complete remission (CR). However, the median CR duration was 18 months, and the median survival was 18 months with a 3-year disease-free survival rate of 25%. There were eight relapses and one lineage switch to acute myelogenous leukemia (AML). Patients with ALL and EM-MPO-positive disease are a unique subgroup with long-term poor prognosis on conventional anti-ALL therapy, and may benefit from intensification treatments with agents effective against AML.

Adolescent↗
PubMed1994

Inhibition of acute myelogenous leukemia progenitor proliferation by macrophage inflammatory protein 1-alpha.

Macrophage inflammatory protein-alpha (MIP-1 alpha), an 8-kDa peptide produced by stimulated macrophages, has been recently sequenced and cloned. In addition to its inflammatory effects, MIP-1 alpha inhibits proliferation of immature hematopoietic progenitors both in vitro and in vivo. Because the gene coding for MIP-1 alpha is expressed in peripheral blood cells obtained from patients with acute myelogenous leukemia (AML), we sought to evaluate the effect of MIP-1 alpha on AML precursors. We studied bone marrow samples from 21 AML patients using both the AML blast colony assay and the delta suspension culture assay. We found that recombinant human (rh) MIP-1 alpha significantly inhibits early and mature AML progenitors with sample-to-sample variability, by up to 79% at concentrations ranging from 40 to 1600 ng/ml. These results were obtained in the presence of fetal calf serum either alone or with granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor, or interleukin-3. In contrast, rhMIP-1 alpha (400 ng/ml) did not significantly affect normal colony-forming unit granulocyte-macrophage (CFU-GM), or burst-forming unit-erythroid (BFU-E) proliferation. These data prompted us to delineate the inhibitory mechanism of MIP-1 alpha. Consequently, we used the thymidine suicide technique to measure DNA synthesis in AML progenitors and the enzyme-linked immunosorbent assay to quantify intracellular levels of interleukin-1 beta in AML blasts following incubation with MIP-1 alpha. We found that whereas MIP-1 alpha prevented AML progenitors from entering the proliferative phase of the cell cycle, it had no effect on interleukin-1 beta levels. Taken together, our data suggest that MIP-1 alpha may have clinical benefits in therapy for AML and should be considered for evaluation in a clinical setting.

Adolescent↗
PubMed1993

Granulocyte colony-stimulating factor supportive treatment following intensive chemotherapy in acute lymphocytic leukemia in first remission.

BACKGROUND: The efficacy of granulocyte colony-stimulating factor (G-CSF) in reducing neutropenia and its associated complications in adults with acute lymphocytic leukemia (ALL) undergoing intensive chemotherapy in first remission was evaluated. METHODS: Fourteen adult patients with ALL in first remission received intensive chemotherapy consisting of mitoxantrone 5 mg/m2 intravenously (IV) over 1 hour daily for 3 days, cytosine arabinoside (ara-C) 3 g/m2 IV over 2 hours every 12 hours x 4 on days 1 and 2, vincristine 2 mg IV on day 1, solumedrol 50 mg IV twice daily for 5 days, and G-CSF 5 micrograms/kg subcutaneously daily starting on day 4 until granulocyte recovery. Their outcome was compared with that of 14 consecutive patients who received the same intensification chemotherapy, but without G-CSF. The latter patients had been entered on the same ALL protocol from April 1990 through June 1991. RESULTS: G-CSF administration was associated with a significant shortening in the duration of neutropenia. The number of days to granulocyte recovery above 0.5 x 10(3)/microliters was 14 in the G-CSF group versus 18 days in the historical group (P < 0.001). Two episodes of documented infections were observed in the G-CSF group compared with four episodes in the historical group. Death during intensification therapy occurred in 2 of 14 patients in the historical group, but in none of the 14 patients receiving G-CSF. CONCLUSIONS: G-CSF as an adjunct to intensive chemotherapy in adults with ALL in first remission yielded positive results. Future studies incorporating growth factors supportive care during remission, induction, and consolidation may reduce treatment-related morbidity and mortality, increase the dose-intensity delivery of therapy, and potentially improve patient outcome.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Fludarabine and cytosine arabinoside in the treatment of refractory or relapsed acute lymphocytic leukemia.

BACKGROUND: The objectives of the study were to evaluate the antileukemic efficacy and toxicity profiles of the combination of fludarabine and intermediate-dose cytosine arabinoside (ara-C) in refractory or relapsed adult acute lymphocytic leukemia (ALL). PATIENTS AND METHODS. Thirty adults with refractory or relapsed ALL were treated. Their median age was 45 years, 60% were in second or subsequent relapse, and 37% had Philadelphia chromosome-positive disease. Treatment consisted of ara-C 1 g/m2 during a period of 2 hours daily for 6 days, and fludarabine 30 mg/m2 during a period of 30 minutes daily for 5 days on days 2-6. Fludarabine was given 4 hours before ara-C to increase the rate of ara-C 5'-triphosphate (ara-CTP) accumulation in leukemic cells. Courses were repeated every 3 weeks or longer, depending on patient response and side effects. RESULTS: Nine (30%) patients achieved a complete remission (CR), 8 (27%) died during remission induction, and 13 (43%) had resistant disease. The median CR duration was 22 weeks, and the median survival was 12 weeks for all patients, and 34 weeks for those who had a response to treatment. Except for low platelet counts, which predicted shorter survival time, no other prognostic factors were demonstrated, considering the small number of patients treated. Myelosuppression-associated febrile episodes were the most common side effects, occurring in 28 (93%) patients. Neurotoxicity was noted in two (7%) patients. CONCLUSIONS: Fludarabine and ara-C are an active and relatively safe antileukemic combination in refractory or relapsed ALL. Future studies will incorporate other anti-ALL agents, such as topoisomerase II-reactive drugs, to improve the overall efficacy, and growth factors, to reduce myelosuppression-related complications.

Adult↗
PubMed1993

Results of fludarabine and prednisone therapy in 264 patients with chronic lymphocytic leukemia with multivariate analysis-derived prognostic model for response to treatment.

Two hundred sixty-four patients with chronic lymphocytic leukemia were treated with fludarabine 30 mg/m2 intravenously for 30 minutes each day for 5 days and with prednisone 30 mg/m2 orally each day for 5 days. Courses were repeated monthly. Of the 264 patients. 125 patients (47%) had Rai stage III-IV disease; 169 patients (64%) were previously treated with a median of 3 prior regimens; and 138 of them (82%) were refractory to therapy with alkylating agents. The overall response (OR) and complete response (CR) rates in the 169 previously-treated patients were 52% and 37%; these were 74% and 63%, respectively, in Rai stage O-II patients and declined to 64% and 46%, respectively, in Rai III-IV disease. Among the previously untreated patients, the OR and CR rates were 79% and 63%, these being 85% and 70%, respectively, in Rai O-II patients, and declining to 64% and 46%, respectively, in Rai III-IV disease. The incidence of minor infections or fever of unknown origin was similar in all patient groups and occurred in 22% of courses. The incidence of sepsis and/or pneumonia was significantly correlated with the extent of prior therapy and with Rai stage, and ranged from 3% of courses in the previously untreated Rai O-II patients, to 13% of courses in the previously treated Rai III-IV patients. Listeria sepsis or Pneumocystis carinii pneumonia was noted in 14 patients. With therapy, CD4 levels were uniformly depressed from a median 1,015/microL pretreatment to a median 159/microL after 3 months of fludarabine therapy. Median time to progression in previously treated patients was 22 months. In previously untreated patients, median time to progression was 30 months for patients who achieved a partial remission and has not been reached in patients who achieved a CR with a median follow-up of 2 years. The median survival was 18 months for previously treated patients and has not been reached for previously untreated patients. Response rates in previously treated and untreated patients, as well as infection rates, were identical to those seen in 110 patients treated with the same dose schedule of fludarabine alone. Logistic regression analysis selected 4 factors to be significantly associated with worse response: Rai III-IV stage disease, prior therapy, older age, and low albumin levels. The regression equation was used to derive a probability of response based on the 4 characteristics. When the model was applied to the same population, patients could be divided into 4 prognostic groups with different outcomes.

Antigens, CD↗
PubMed1993

Long-term follow-up of patients with chronic lymphocytic leukemia treated with fludarabine as a single agent.

The clinical response and survival of 113 patients with at least 3-year follow-up after treatment with fludarabine as a single agent for chronic lymphocytic leukemia has been evaluated. Seventy-eight patients were previously treated and 35 were untreated. The response to therapy and survival were strongly correlated with the degree of previous therapy, the stage of disease, and whether or not the patients were refractory to alkylating agents. Other characteristics associated with survival were the age of the patient and the serum albumin level at the start of therapy. The median time to progression of responders who had not received prior therapy was 33 months and was 21 months for previously treated patients. Survival after progression of disease was also strongly correlated with the degree of prior therapy. No successful salvage regimen after initial fludarabine therapy was shown for patients refractory to alkylating agents, although fludarabine achieved further remissions in patients who had received fludarabine as their initial treatment or were not refractory to alkylating agents. The morbidity of patients in unmaintained remission on discontinuation of fludarabine was low, with less than one episode of infection per patient-year at risk. The morbidity during this time was correlated with clinical response and whether the patients had received prior therapy. Although fludarabine is a very effective cytoreductive regimen, most patients, including those who achieved true complete remissions, will have recurrent disease. Longer follow-up and comparative trials are required before the effect of fludarabine on survival is shown.

Adult↗
PubMed1993

Treatment of Waldenstrom macroglobulinemia with 2-chlorodeoxyadenosine.

OBJECTIVE: To evaluate the activity of 2-chlorodeoxyadenosine (2CdA) in the treatment of patients with Waldenstrom macroglobulinemia. DESIGN: Uncontrolled phase II trial. SETTING: Tertiary, referral cancer center. PATIENTS: Twenty-nine consecutive, symptomatic patients with Waldenstrom macroglobulinemia, of whom 9 were previously untreated. INTERVENTION: 2-Chlorodeoxyadenosine was administered as a continuous intravenous infusion at a dose of 0.1 mg/kg body weight per day for 7 days. Only two courses of 2CdA were given and responding patients were then followed without further treatment. MEASUREMENTS AND MAIN RESULTS: A total of 17 (59%) patients responded, including all of those who were newly diagnosed and 40% of those who had failed previous therapies. Treatment was well tolerated except for one death in a patient who had presented with severe pancytopenia. With a median follow-up of 7 months, only one responding patient has relapsed. CONCLUSION: 2-Chlorodeoxyadenosine is a nucleoside analog that was effective in most patients with Waldenstrom macroglobulinemia and was associated with little toxicity.

Adult↗
PubMed1993

An open trial of cefoperazone plus sulbactam for the treatment of fever in cancer patients.

Cancer patients received cefoperazone plus sulbactam for 673 febrile episodes presumed to be caused by infection. Overall, 415 (76%) of the 545 evaluable episodes responded. There were 213 responses (84%) amongst the 254 fevers of unknown origin and 202 responses (69%) amongst the 291 documented infections. Fifty-one (61%) of the 83 episodes pneumonia and 74 (64%) of the 115 episodes of bacteraemia responded. Only 39 (58%) of the 67 infections caused by Gram-positive bacteria responded compared with 55 (86%) of 64 Gram-negative infections which included seven of eight caused by Pseudomonas aeruginosa. Eighteen (67%) of 27 polymicrobial infections responded to the regimen. Response rates were significantly lower amongst the 125 patients whose neutrophil counts decreased during therapy than amongst the 158 patients whose neutrophil counts increased. Adverse events which were possibly or probably related to antibiotic therapy were observed during 73 of the episodes; the most commonly reported side-effects were diarrhoea and skin rash. Six patients developed a coagulopathy without haemorrhage and two experienced anaphylactic reactions. In this open trial cefoperazone plus sulbactam proved to be an effective regimen for initial therapy of fever in cancer patients. It should be combined with a glycopeptide in those institutions where infections caused by methicillin-resistant staphylococci are frequently encountered.

Adolescent↗
PubMed1993

Fludarabine potentiates metabolism of cytarabine in patients with acute myelogenous leukemia during therapy.

PURPOSE: A protocol was designed to test the hypothesis that fludarabine infusion before arabinosylcytosine (cytarabine [ara-C]) would increase the accumulation of the active metabolite ara-C triphosphate (ara-CTP) in acute myelogenous leukemia (AML) blasts during therapy. PATIENTS AND METHODS: Patients (n = 5) received 1 g/m2 of ara-C infused intravenously (IV) for 2 hours, followed at 20 hours by 30 mg/m2 of fludarabine for 30 minutes. At 24 hours, another identical dose of ara-C was infused. To determine the optimal duration of ara-C infusion following fludarabine, five additional patients were treated on an amended protocol in which the ara-C infusion was extended to 3 g/m2 infused over 6 hours. RESULTS: Comparison of ara-CTP pharmacokinetics in circulating AML cells demonstrated that the area under the curve (AUC) of ara-CTP increased significantly (median, 1.8-fold; range, 1.6 to 2.4; P = .004) after fludarabine infusion. Neither the median plasma ara-C concentrations, the levels of its deamination product arabinosyluracil, nor the rate of ara-CTP elimination from circulating blasts was affected by fludarabine infusion. However, the rate of ara-CTP accumulation by AML cells was increased by a median of 2.0-fold (range, 1.8 to 2.2; P = .001) after fludarabine; the peak occurred within 1 hour of the end of the infusion. In vitro incubation of these cells with arabinosyl-2-fluoroadenine (F-ara-A) before ara-C also produced a median 1.7-fold increase in the ara-CTP accumulation rate. Pharmacology studies in patients receiving 6-hour infusions of ara-C demonstrated that the rate of ara-CTP accumulation was potentiated beyond 2 hours, but not for 6 hours. CONCLUSION: Infusion of fludarabine before ara-C augments the rate of ara-CTP synthesis in circulating AML blasts during therapy. Evaluation of 6-hour ara-C infusions demonstrated that potentiation of ara-CTP synthesis is maximal up to 4 hours in most patients; this pharmacologically optimized regimen should be considered for combination with other antileukemia drugs.

Adolescent↗