Total Daunorubicin Research Articles

Disposition of liposomal daunorubicin during cotreatment with cytarabine in patients with leukaemia.

To investigate the pharmacokinetics and pharmacodynamics of liposomal daunorubicin (DaunoXome) 80 or 100 mg/m(2) on days 1, 2 and 3 coadministered with standard or high-dose cytarabine to patients with poor-risk acute leukaemia. Unblinded pharmacokinetic-pharmacodynamic study. Twenty-three adult patients with acute leukaemia. Blood, bone marrow and urine samples were collected at appropriate intervals on days 1-6. Total daunorubicin and daunorubicinol concentrations in plasma, bone marrow, peripheral blood cells and urine were measured by high performance liquid chromatography. Liposomal daunorubicin exhibited a markedly different pharmacokinetic behaviour from the free drug due to a slow distribution of the liposomal moiety into the body. The ratio of area under the concentration-time curve (AUC) for metabolite to parent drug was lower for liposomal daunorubicin than for free daunorubicin, mainly due to higher concentrations of the parent drug in plasma, whereas daunorubicinol exposure was more or less comparable, if not higher. After liposomal daunorubicin at both 80 and 100 mg/m(2), total daunorubicin concentrations in leukaemic cells were at least similar to those observed for free daunorubicin, and significant accumulation was also observed in bone marrow blast cells. Nineteen of 23 patients obtained a complete remission, although 13 had P-glycoprotein-overexpressing blast cells. Grade 3-4 mucositis was found only in three patients with very high AUCs for total daunorubicin and daunorubicinol. Liposomal daunorubicin at both 80 and 100 mg/m(2) in combination with cytarabine may represent a valid treatment for high-risk acute leukaemia. Liposomal daunorubicin may be helpful in overcoming multidrug resistance, since it shows significant accumulation into tumour target cells, irrespective of P-glycoprotein expression. The tolerability profile suggests that toxicity may be related to exposure to both the parent drug and the metabolite.

Recent advances in pediatric acute lymphoblastic and myeloid leukemia.

Acute leukemia is the most common form of childhood cancer and is the primary cause of cancer-related mortality in children. In the United approximately 3250 cases are diagnosed annually in children and adolescents younger than 20 years, of whom 2400 have acute lymphoblastic leukemia (ALL). Treatment results in childhood ALL continue to improve, and the expected current cure rates approach 75 to 80% of all children with ALL, including T-ALL and mature B-cell ALL, the two variants that, not too long ago, had a considerably poorer prognosis compared with the common form of BpALL. The most significant new development in the past 2 years has been the development of further evidence for fetal origin of childhood leukemias, and additional evidence to support the notion that postnatal events modulating the events of immune-mediated elimination of these leukemic clones play a major role in the eventual development of clinical disease. Other epidemiologic developments include (1) increased appreciation of the role of drug-metabolizing enzymes, both in determining the predisposition to leukemia and response to therapy; and (2) both clinical observations and gene expression studies seeming to identify a new approach to the evaluation and treatment of children with MLL (11q23) rearrangements. A most remarkable new development in the induction therapy of childhood leukemia and lymphoma in the United States is the use of urate oxidase for prevention of tumor lysis syndrome and the associated uric acid nephropathy. Drug resistance, determined either on leukemic blast cells in vitro or by studies of MRD, is being looked at critically in an effort to improve the treatment results further. Consolidation with HDMTX has gained wider popularity with the realization that effective CNS prophylaxis can be achieved with intrathecal therapy plus HDMTX for consolidation. In contrast to ALL, the progress in the therapy of acute myeloid leukemia (AML) lags behind, with cure rates of approximately 40 to 50%. There is no convincing evidence for substitution of daunorubicin with other anthracyclines, nor evidence for using high-dose cytarabine during induction in childhood AML. Rather, a 3 + 10 regimen with total daunorubicin 180 mg/m2 and cytarabine 100 to 200 mg/2 for 10 days appears to yield the best results. The most important component of the postremission chemotherapy continues to be several courses of high-dose cytarabine. The results from the MRC 10, LAME 89/91 studies and the recent BFM 93 trial with high-dose cytarabine and mitoxantrone suggest that there may be some benefit to including this combination in the postremission phase of AML. Despite these improvements in chemotherapy, allogeneic BMT from a matched family donor remains the best option for most patients (excluding Down syndrome, APL, and possibly those with inv16). Newer prognostic markers of interest include FLT3/ITD and minimal residual disease at the end of induction therapy.

Kinetics of daunorubicin transport by P-glycoprotein of intact cancer cells.

Drug permeation across the plasma membrane of multidrug-resistant cells depends on the kinetics of the P-glycoprotein-mediated pump activity as well as on the passive permeation of the drug. We here demonstrate a method to characterize kinetically the pump in intact cells. To this purpose, we examined the membrane-transport properties of daunorubicin in various sensitive cancer cell lines and in their multidrug resistant (MDR) counterparts. First, we determined the passive permeability coefficient for daunorubicin. Then, using a flow-through system, the drug flux into the cell was measured after inhibition of the P-glycoprotein-mediated efflux pump. Combining the two results allowed us to calculate the intracellular free concentration of the drug. In the steady-state, the pump rate must equal the net rate of passive diffusion of the drug and, therefore, the same experiments gave us the pumping rate of daunorubicin. These experiments were then repeated at various extracellular drug concentrations. By plotting the pumping rate versus the intracellular drug concentration, we then characterized the P-glycoprotein kinetically. Four independent methods were used to measure the passive permeability coefficient for the cell line A2780. Similar values were obtained. Maximal pump rates (Vmax) showed a good correlation with the amount of P-glycoprotein in the cell lines used. We obtained saturation curves for the variation of the pump rates with the intracellular daunorubicin concentrations. These curves were typical for positive cooperativity, which provides evidence that at least two binding sites for daunorubicin are present on the active transport system of daunorubicin. The apparent Km values for P-glycoprotein-mediated transport, the intracellular free cytosolic daunorubicin concentrations at half-maximal velocity for the cell lines used, were approximately 1.5 microM. Except for the cell lines with the highest amount of P-glycoprotein, the passive efflux rate of daunorubicin proved to be a substantial part of the total daunorubicin efflux rate for the cell lines used. In cell lines with relatively low levels of P-glycoprotein, passive daunorubicin efflux was even the main route of daunorubicin transport from the cells, determining the intracellular steady-state concentrations of daunorubicin.

Anthracycline cardiomyopathy in childrenReport of two cases

Two children with leukemia are presented, each demonstrating an unusual aspect of anthracycline-induced cardiomyopathy. In the first patient (a 7-month-old female with acute monocytic leukemia) extremely young age and previous chemotherapy with a podophyllotoxin derivative, VP-16, may have prediposed the patient to fatal congestive heart failure at a total Daunorubicin dose of only 225 mg/m2. In the second patient, a delay of 4 1/2 years was not sufficient in preventing congestive heart failure resulting from the administration of additional anthracycline chemotherapy. We conclude that extremely young age and, possibly, prior therapy with VP-16 may be addition risk factors in the development of anthracycline cardiomyopathy. Also, we suggest that once an anthracycline agent has reached a toxic threshold for the myocardium, the heart may always be at risk to injury from additional Adriamycin or Daunorubicin therapy.