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Biomedical subjects

W Plunkett

Publications and source records attributed to W Plunkett.

At least 91 records · Page 5Linked to original sources
PubMed1994

Combination of fludarabine and arabinosylcytosine for treatment of chronic lymphocytic leukemia: clinical efficacy and modulation of arabinosylcytosine pharmacology.

Previous studies have demonstrated that treatment with fludarabine 4 h prior to arabinosylcytosine (ara-C) potentiates the accumulation of the active triphosphate of ara-C (ara-CTP) in leukemic lymphocytes. The clinical efficacy of this combination was evaluated in 15 patients with chronic lymphocytic leukemia (CLL) that was advanced in their disease (median Rai stage, IV) and refractory to treatment with fludarabine. Patients received 0.5 g/m2 ara-C infused i.v. over 2 h followed at 20 h by a 30-min infusion of 30 mg/m2 fludarabine. At 24 h, an identical dose of ara-C was infused. To intensity the therapy and to determine the duration of fludarabine potentiation of ara-CTP accumulation, six additional patients with Rai stage III or IV CLL were treated with an amended 2-week protocol. On week 1, 30 mg/m2 fludarabine was infused over 30 min, followed 4 h later by a 2-h infusion of 0.5 g/m2 ara-C; on week 2, the fludarabine dose was followed 4 h later by a 4-h infusion of ara-C (1.0 g/m2). In all, 1 partial remission and 7 minor responses in 1 or more disease sites were observed in the 21 patients. The major treatment-related toxic effects were myelosuppression and infection. Comparison of the ara-CTP accumulation area under the concentration-time curve (AUC) in circulating CLL cells of patients on the amended protocol demonstrated a significant (P = 0.001) 1.6-fold (range, 1.4- to 2.0-fold) increase after fludarabine administration. Although the initial rates of ara-CTP accumulation were similar for the 2-h and 4-h infusions, ara-CTP accumulation continued for up to 4 h in four of five patients who received the longer infusion. The activity of the fludarabine and ara-C combination is being evaluated in in vitro model systems and in phase II clinical trials in combination with other drugs.

Adult↗
PubMed1994

The role of fludarabine in hematological malignancies.

Fludarabine monophosphate, a synthetic nucleoside analog, has been shown to have considerable activity in a number of lymphoid malignancies. In chronic lymphocytic leukemia the response rates can exceed 70% with a considerable proportion of complete remissions being attained. These rates are markedly superior to earlier therapies with which complete remission was uncommon. It also has significant activity in previously treated patients for whom effective salvage regimens were unsatisfactory. In addition, fludarabine shows substantial activity in low grade non-Hodgkin's lymphoma, both as initial treatment and as salvage therapy. Fludarabine is effective in Waldenstrom's macroglobulinemia and is active in other low grade lymphoid malignancies. Major toxicities are reversible myelosuppression and depletion of T lymphocytes. The use of fludarabine in hematological malignancies will be reviewed, with reference to its mode of action and future use in combination therapies.

Adult↗
PubMed1994

Fludarabine--present status and future developments in chronic lymphocytic leukemia and lymphoma.

BACKGROUND: Fludarabine monophosphate (fludarabine) is an adenine nucleoside analogue active in indolent lymphoproliferative diseases which has an increasing role in studies incorporating combinations of agents which exploit biochemical modulation, inhibition of DNA repair, and radiosensitizing effects. PATIENTS AND METHODS: Patients with lymphoma and chronic lymphocytic leukemia (CLL) treated at the M. D. Anderson Cancer Center (MDACC) and reports in the literature form the basis of this report. RESULTS: CLL has traditionally been treated with alkylating agents and corticosteroids. In this study, fludarabine has shown marked cytoreductive ability in both previously treated patients and untreated patients. In the former group, there has been a 55% response rate in 374 patients, and 79% in the untreated CLL group. Fludarabine has also been very active in the management of low-grade lymphomas, with two-thirds of patients with follicular lymphoma and half of those with other indolent lymphomas responding. Waldenstrom's macroglobulinemia is also sensitive to the effects of fludarabine. Combination regimens were developed incorporating the substantial effectiveness of fludarabine and mitoxantrone where in the previously treated low-grade lymphoma group 25 of 28 patients (89%) responded. Fludarabine has the effect of increasing the triphosphate form of cytosine arabinoside in acute and chronic leukemic cells. This modulation has now been translated into therapy for acute leukemia and combined with cisplatinum in refractory CLL. Fludarabine inhibits DNA repair and enhances cross-linking of DNA by cisplatinum. The combination of fludarabine, ara-C, and cis-platinum is now being used in refractory CLL. Fludarabine is a radiation sensitizer, inhibiting repair of DNA damage. Studies are ongoing with this combination. CONCLUSIONS: Fludarabine is a potent molecule with a wide range of biochemical effects. Optimal use of this drug alone and in combination is continuing to be explored.

Adrenal Cortex Hormones↗
PubMed1994

High-dose mercaptopurine followed by intermediate-dose cytarabine in relapsed acute leukemia.

PURPOSE: This phase I/II study was designed to explore the feasibility, toxicity, and potential efficacy of administering high-dose continuous intravenous mercaptopurine (6MP) followed by intermediate-dose continuous intravenous cytarabine (Ara-C) to children with relapsed or unresponsive acute leukemia. PATIENTS AND METHODS: Twenty-three children with relapsed or unresponsive acute leukemia (13 myeloid, 10 lymphoid) were entered onto the study. After initial hydration and alkalinization, 1,000 or 1,250 mg/m2 of 6MP was administered by continuous intravenous infusion over 24 hours. Following another period of hydration, 500 mg/m2 of Ara-C was administered by continuous intravenous infusion daily for 4 days. In 17 children, plasma concentrations of 6MP were measured at hours 4, 24, and 27 of the 6MP infusions. Plasma concentrations of Ara-C were measured at hours 8, 24, 48, 72, and 96 of the Ara-C infusions. Intracellular Ara-C triphosphate (Ara-CTP) concentrations were measured in peripheral-blood leukemia cells of the five patients with sufficient cells for measurement. Children who developed remission received repeated courses of this regimen every 3 to 4 weeks until relapse or completion of 12 courses. RESULTS: Of 13 children with acute myeloid leukemia (AML), six developed complete remissions (CRs) lasting 7 months to nearly 4 years. Two children remain in CR with normal growth, development, and health 3 years after cessation of treatment. Of 10 children with acute lymphoid leukemia (ALL), one had a CR of 2 months' duration. Dose-limiting toxicity consisted of severe hematosuppression with fever, neutropenia, and serious infection. There were two toxic deaths. The mean steady-state plasma concentrations of 6MP were approximately 4 mumol/L and of Ara-C approximately 3 mumol/L. The median Ara-CTP concentration in peripheral-blood leukemia cells was 308 mumol/L at hour 8 of the Ara-C infusion. CONCLUSION: High-dose continuous intravenous 6MP followed by intermediate-dose intravenous Ara-C produced CRs of longer than 6 months in approximately half of children with relapsed or unresponsive AML. Further study of this drug regimen is justified.

Acute Disease↗
PubMed1994

Evolution of the arabinosides and the pharmacology of fludarabine.

An understanding of the pharmacokinetics of a drug is essential to the optimal design of the dose and schedule of chemotherapy protocols. As an extension, knowledge of the mechanism of drug action is necessary to construct the optimal strategy for combination chemotherapy. Nucleoside antimetabolites such as arabinosylcytosine, arabinosyladenine, and fludarabine are prodrugs that must enter cells and be phosphorylated to the respective triphosphates before they can elicit biological activity. DNA synthesis is the major metabolic target for this class of compounds. Common to members of the arabinosyl nucleoside class is the finding in experimental systems of a relationship between incorporation of each drug into DNA and the loss of clonogenicity. Although additional inhibitory mechanisms have been identified, they all require formation of the respective triphosphate. Thus, knowledge of the pharmacokinetics of the triphosphates in target cells and an understanding of the mechanisms by which these active forms of arabinosyl nucleosides kill cells are indispensable to the rational design of treatment protocols. This article considers the clinical development of arabinosyl nucleosides with respect to investigations of their pharmacokinetics and mechanisms of action. An understanding of these elements of arabinosyl nucleoside metabolism should provide a rationale for combinations with other chemotherapeutic agents and anticancer modalities.

Animals↗
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

Fludarabine inhibits DNA replication: a rationale for its use in the treatment of acute leukemias.

Fludarabine is a prodrug that must enter cells and be phosphorylated to the nucleoside triphosphate, F-ara-ATP, to elicit biological activity. F-ara-ATP serves as an inhibitory alternative substrate in several key processes involved in DNA synthesis. The enzymes required in DNA synthesis and affected by F-ara-ATP are ribonucleotide reductase, DNA primase, DNA polymerases, 3'-5' exonuclease activity of DNA polymerases delta and epsilon, and DNA ligase I. The action of fludarabine on DNA replication provides a compelling rationale to use this agent for leukemias where target cells are actively synthesizing DNA, for example acute myelogenous leukemia. Additionally, the role of F-ara-ATP to potentiate the activity of deoxycytidine kinase makes it an appropriate candidate to use in combination with other nucleoside analogs which require deoxycytidine kinase for their activation. The present article reviews the effect of fludarabine on enzymes involved in DNA synthesis and the role of fludarabine in combination with arabinosylcytosine for the treatment of diseases other than indolent leukemias.

Acute Disease↗
PubMed1994

Long-term results following treatment of newly-diagnosed acute myelogenous leukemia with continuous-infusion high-dose cytosine arabinoside.

The long-term results in 130 patients with newly diagnosed acute myelogenous leukemia treated with continuous infusion high-dose ara-C (1.5 gm/m2/day x 4 days, CIHDAC) were compared with those in 264 patients treated in previous studies with standard dose ara-C (70-90 mg/m2/d x 7 days) plus either adriamycin (Ad-OAP), or amsacrine (AMSA-OAP). All patients have been followed at least 5 years. Patients in first CR at 5 years (FCR5) treated on protocols prior to CIHDAC had only 5% chance of relapse (median subsequent follow-up of 9 years). Therefore, we considered patients in FCR5 potentially cured. The two groups were similar with respect to known prognostic factors and CR rates. Although remission duration and survival were shorter with CIHDAC than Ad-OAP/AMSA-OAP, the percent of patients potentially cured was similar (10 vs. 15%). Marked differences between regimens were seen in inv(16) and t(15;17) patients. CIHDAC was better for patients with inv(16) with more patients in FCR5 (80 vs. 38%), longer remission duration and survival, and lower incidence of CNS relapse (0 vs. 43%). The Ad-OAP/AMSA-OAP protocols were superior in patients with t(15;17). We also measured steady-state ara-CTP concentrations (ara-CTPss) in 54 CIHDAC-treated patients presenting with high-blast count. While there was no correlation between ara-CTPss and response duration, all five patients in FCR5 in whom ara-CTPss was measured had high concentrations. These data support the concept that patients with AML should be treated differently according to cytogenetics. Inv(16) patients should be treated with high-dose ara-C while t(15;17) should rely more on anthracycline exposure.

Adolescent↗
PubMed1994

Effect of granulocyte-macrophage colony-stimulating factor on the metabolism of arabinosylcytosine triphosphate in blasts during therapy of patients with chronic myelogenous leukemia.

Because in vitro studies have indicated that granulocyte-macrophage colony-stimulating factor (GM-CSF) stimulates arabinosylcytosine (ara-C) metabolism in leukemia blasts, we analyzed the pharmacokinetics of ara-C triphosphate (ara-CTP) in the blasts of patients with chronic myelogenous leukemia who were undergoing therapy with GM-CSF and ara-C. Patients received a 2-h infusion of 1.0 g/m2 ara-C followed by daily infusions of GM-CSF (125 micrograms/m2/day i.v. over 6 h) for 2-4 days. After the last GM-CSF infusion, a second, identical dose of ara-C was administered. The cellular pharmacokinetics of ara-CTP in circulating blasts were determined during and after each ara-C dose, and the area under the accumulation and elimination curve (AUC) measured over 12 h was compared before and after GM-CSF. Ara-CTP accumulation peaked within 1 h after the end of each ara-C infusion. Comparison of the AUC of ara-CTP before and after GM-CSF administration suggested that in the blasts of three of four patients, GM-CSF treatment decreased the ara-CTP AUC; the AUC values were altered only slightly in a fourth patient. Studies of these patients' blasts incubated in vitro with ara-C before and after clinical infusion of GM-CSF revealed similar ara-CTP accumulation patterns. Together, these studies suggest that 2-4 days of GM-CSF administration does not increase the accumulation of ara-CTP in the circulating blasts from patients in the blastic phase of chronic myelogenous leukemia.

Arabinofuranosylcytosine Triphosphate↗
PubMed1993

Regulation of thymidine kinase and thymidylate synthase in intact human lymphoblast CCRF-CEM cells.

It has been reported that thymidylate synthase (TS) is a component of a multienzyme complex associated with DNA replication based on observations that enzyme activity was decreased when cells were treated with various DNA synthesis inhibitors (Plucinski, T. M., Fager, R. S., and Reddy, G. P. V. (1990) Mol. Pharmacol. 38, 114-120). The veracity of the TS assay (known as the tritium release assay) employed in these experiments may be compromised, however, because it requires the S phase-specific enzyme thymidine kinase (TK) to phosphorylate the substrate [5-3H]dUrd. In our study, this problem was further illustrated as the phosphorylated products of [14C]dCyd and [6-3H]dUrd were simultaneously quantitated to determine the activities of TS, TK, and dCyd kinase in intact CCRF-CEM cells. TS and dCyd kinase were unaffected by aphidicolin, hydroxyurea, and 1-beta-D-arabinofuranosylcytosine, whereas TK was strongly inhibited by these agents. Elevation of the cellular dTTP pool that accompanied drug treatment was not the primary mechanism affecting TK activity because incubation of cells with dCyd elevated the dTTP pool to similar levels, but did not inhibit TK to the same extent as did the drugs. Furthermore, after cells were washed from aphidicolin, [6-3H]dCyd incorporation, which primarily labels dTMP in DNA, proceeded at a linear rate, whereas a lag period of 15 min was observed before [3H]dThd was incorporated at a linear rate. These results suggest that TK activity is affected by more than one mechanism in intact cells. Because the activities of dCyd kinase and dCMP deaminase do not fluctuate as much as that of TK in response to changes in DNA synthesis activity and cell cycle, dCyd incorporation appears to be a more reliable assay of TS in intact cells than does dUrd incorporation. Our findings also imply that [3H]dThd incorporation assays may overestimate inhibition of DNA synthesis.

Aphidicolin↗
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

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

Phase I study of Topotecan, a new topoisomerase I inhibitor, in patients with refractory or relapsed acute leukemia.

The purpose of this study was to define, in a phase I study in leukemia, the maximally tolerated dose (MTD), major toxicities, and possible antitumor activity of Topotecan, a new topoisomerase I (topo I) inhibitor. Topotecan was delivered by a 5-day continuous infusion every 3 to 4 weeks to patients with refractory or relapsed acute leukemia, at doses ranging from 3.5 mg/m2 to 18 mg/m2 per course. Twenty-seven patients were treated, including 17 patients with acute myelogenous or undifferentiated leukemia, 7 with acute lymphocytic leukemia, and 3 with chronic myelogenous leukemia in blastic phase. Severe mucositis was the dose-limiting toxicity occurring in two of five patients treated with Topotecan 11.8 mg/m2 per course; a third patient had prolonged myelosuppression. At the MTD of 10 mg/m2 per course, 1 of 12 patients had severe mucositis and 5 had mild-to-moderate mucositis. Nausea, vomiting, diarrhea, and prolonged myelosuppression were uncommon. Three patients (11%) achieved a complete response, two (7%) had a partial response, and one (4%) had a hematologic improvement. The overall complete plus partial response rate was 19%, and 24% in acute myelogenous or undifferentiated leukemia. A novel in vitro assay that quantifies Topotecan-stabilized topo I-DNA complexes in patient samples was used, which demonstrated heterogeneity in the ability of Topotecan to interact with topo I, the intracellular target of Topotecan. This phase I study defined the MTD of Topotecan to be 10 mg/m2 by continuous infusion over 5 days every 3 to 4 weeks in patients with refractory or relapsed acute leukemia. Severe mucositis was the dose-limiting toxicity. Future studies will define the precise activity of Topotecan in different leukemia subsets, its efficacy in combination with other antileukemic drugs, and correlations between Topotecan-induced topo I-DNA complex formation and individual patient response to Topotecan.

Acute Disease↗
PubMed1993

Induction of apoptotic cell death in chronic lymphocytic leukemia by 2-chloro-2'-deoxyadenosine and 9-beta-D-arabinosyl-2-fluoroadenine.

2-Chloro-2'-deoxyadenosine (CldAdo) and 9-beta-D-arabinosyl-2-fluoroadenine (F-ara-A) have shown marked activity in the treatment of indolent lymphoid malignancies. Based on the susceptibility of various lymphocyte populations to apoptosis, we investigated whether CldAdo or F-ara-A would induce this process in lymphocytes from patients with chronic lymphocytic leukemia (CLL). In vitro exposure of leukemic lymphocytes to CldAdo or F-ara-A for 24 to 72 hours elicited features of apoptosis visible by light and electron microscopy. Analysis of DNA integrity showed DNA cleavage into nucleosomal-sized multimers. Using a quantitative assay, drug-induced DNA fragmentation was both time and dose dependent. Inhibition of active macromolecular synthesis did not prevent drug-induced fragmentation; however, both drug-induced and spontaneous DNA fragmentation were prevented by intracellular calcium chelation. In vitro culture with phorbol ester generally decreased drug-induced DNA cleavage. After prolonged incubation, CLL cells exhibited spontaneous cleavage; albeit, at significantly lower rates than drug-treated cells. Heterogeneity was observed for spontaneous and drug-induced DNA fragmentation and was significantly lower in B-leukemic cells obtained from patients with high-risk and refractory disease. We conclude that CldAdo and F-ara-A are potent inducers of apoptotic death in CLL and that this feature correlates with the disease status.

Adenosine Triphosphate↗
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↗
PubMed1993

Chronic lymphocytic leukemia--correlation of response and survival.

Chronic lymphocytic leukemia (CLL) is considered to be an incurable hematologic malignancy using conventional therapy. Complete remissions (CR) were unusual with conventional approaches such as chlorambucil with or without prednisone or cyclophosphamide, vincristine, and prednisone (CVP). Pathologic complete remissions including negative bone marrow biopsies were seldom mentioned in the literature. Two parameter flow cytometry has demonstrated that CLL cells co-express CD5 and pan-B cell antigens such as CD19 and CD20. In addition, immunoglobulin gene rearrangement occurs predictably in B-cell CLL and can be used as a further marker of completeness of remission. The National Cancer Institute (NCI) has published criteria for complete remission which allow persistent lymphoid nodules to be present on the bone marrow biopsy and the patient can be considered in complete remission. Our group has considered these patients to have a nodular CR (Nod CR) to separate them from having a true remission on bone marrow biopsy (CR-bx). Thus bone marrow biopsy criteria, two parameter flow cytometry, and immunoglobulin gene rearrangement are now available for routine clinical application to re-define completeness of remission in CLL. With the use of fludarabine monophosphate (Fludara), complete and partial responses are obtained in 50-55% of previously treated patients with CLL and 75-80% of patients with previously untreated CLL. There was a strong correlation of probability of response with degree of previous therapy, stage of disease, age, hemoglobin level, platelet count, serum albumin and beta 2-microglobulin, and bone marrow infiltration with lymphocytes. Patients can be identified as being at high/low risk of achieving a complete or partial response.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Agents↗