Expression of the multidrug resistance-associated protein (MRP) mRNA and protein in normal peripheral blood and bone marrow haemopoietic cells

We studied the expression of multidrug resistance-associated protein (MRP) in normal haemopoietic cells from peripheral blood and bone marrow. The MRP mRNA levels were estimated by RT/PCR and in situ hybridization (ISH) assay, and the protein levels by flow cytometry. 21 samples of peripheral blood and 21 samples of bone marrow (11 normal bone marrow donors, 10 patients in complete remission after chemotherapy for large cell lymphoma or acute myeloid leukaemia) were analysed. In peripheral blood the mean MRP mRNA level in CD3+ cells was statistically higher than in the other cells (3-fold by the methods used). The levels of MRP in CD3+ varied from one individual to another (4.5-34.8 units by RT/PCR and 5-23 grains/cell by ISH); however, this was proportional to the variation in all the cell lineages of same individual (r = 0.84). In bone marrow the mean MRP levels of the various cell lineages (including CD34+) were similar to the basal level in HL60 cells. Individual expression levels were again variable; however, there was no difference between untreated normal bone marrow and post chemotherapy normal bone marrow. MRP protein expression was determined by flow cytometry with the monoclonal antibody MRPm6. The CD4+ lymphocytes exhibited a higher MRP protein expression than the other cell lineages, including CD8+ cells. There was a good correlation between the three methods used (RT/PCR and ISH, P = 0.0001, r = 0.87; RT/PCR and flow cytometry, P = 0.0001, r = 0.85; ISH and flow cytometry, P = 0.002, r = 0.67).

Timed sequential chemotherapy for advanced acute myeloid leukemia

Timed sequential chemotherapy (TSC) combining mitoxantrone on days 1-3, etoposide on days 8-10 and cytarabine on days 1-3 and 8-10, was administered to 240 patients with advanced acute myelogenous leukemia (AML). Sixty one percent of patients, with a 95% confidence interval (CI) ranging from 54 to 67%, achieved complete remission (CR), including 47% (CI: 38-55%) of refractory patients and 78% (CI: 70-86%) of late first relapse patients (p < 0.0001). Thirty percent of patients did not respond to therapy and 9% died from toxicity. Median duration of neutropenia was 32 days and of thrombocytopenia 29 days. Severe non hematologic toxicity included sepsis in 45% of patients and mucositis in 27%. Post-remission therapy varied but included maintenance chemotherapy in most patients, a second course of TSC in 27, autologous stem cell transplantation in 17 and allogeneic transplantation in 20. Median survival of patients who were not transplanted was 7 months with 13% (CI: 7-19%) survival at 5 years. Median disease-free survival (DFS) was 9 months with 13% (CI: 6-20%) DFS at 5 years. Previous refractoriness was the main factor associated with poor prognosis for achieving CR, DFS and survival in a multivariate analysis. There was no difference in DFS between patients receiving the different modalities of intensive post-remission therapy. These results confirm initial reports on TSC and show that some patients with first relapse off therapy can enjoy prolonged DFS using chemotherapy only.

Sequential emergence of MRP- and MDR1-gene over-expression as well as MDR1-gene translocation in homoharringtonine-selected K562 human leukemia cell lines

To investigate the mechanism of resistance to an antineoplastic natural product homoharringtonine (HHT) in leukemic cells, we have established 5 sub-lines of human myeloid leukemia K562 cells, designated as K-H30, K-H100, K-H200, K-H300 and K-H400, which showed progressive resistance to different concentrations of HHT. These sub-lines were cross-resistant to daunorubicin, vincristine, etoposide and mitoxantrone, but not to melphalan. Immunofluorescence with monoclonal anti-Pgp antibody MRK16 and Northern-blot analysis demonstrated that resistance to HHT is related to the sequential emergence of MRP- and MDR1-gene over-expression. In the low-level-resistant K-H30 sub-line, the MDR1 gene was not over-expressed, but the MRP gene was over-expressed 2.1-fold. In the intermediate-level-resistant K-H100 and K-H200 sublines, both the MRP and the MDR1 genes were over-expressed. However, in the high-level-resistant K-H300 and K-H400 sublines, MDR1-gene over-expression predominated (20- and 21-fold respectively). On the other hand, GST pi-gene expression was decreased in all 5 sub-lines. Southern-blot analysis revealed no MRP-gene amplification in any of the 5 sub-lines, whereas the MDR1 gene was amplified in the high-level-resistant K-H300 and K-H400 sub-lines. The most interesting observation is a homogeneously staining region (HSR) found in chromosome 2 of the K-H300 and K-H400 sub-lines. Chromosome painting and in situ hybridization demonstrated that this HSR was translocated from chromosome 7 and consisted of the amplified MDR1 gene, suggesting that there is a relationship between MDR1-gene, translocation and MDR1-gene amplification.

Homoharringtonine: an effective new natural product in cancer chemotherapy

Homoharringtonine (HHT) is a cytotoxic alkaloid isolated from the evergreen tree cephalotaxus harringtonia native to the southern provinces of China. The principal mechanism of action of HHT is the inhibition of protein synthesis in a dose- and time-dependent manner by acting on the ribosomes of cancer cells. It blocks the progression of cells from G1 phase into S phase and from G2 phase into M phase. It is synergestic or additive in vitro with AraC, amsacrine, actinomycin D and dexamethasone. Clinical studies have indicated that HHT is effective in treating acute myeloid leukemia (AML), chronic myeloid leukemia (CML) and myelodysplastic syndrome (MDS), but not acute lymphoblastic leukemia (ALL) and solid tumors. The dose limiting toxicities are hypotention and myelosuppression. Homoharringtonine has relatively mild extramedullary toxicities and no anthracycline-like cardiac toxicity, which make it a suitable candidate for the treatment of aged patients. Pharmacological studies indicate that HHT belongs to the category of multidrug resistance (MDR)-related drugs. The cells resistant to HHT are cross-resistant to anthracycline, vinca alkaloids, mitoxantrone, but not cis-platine and AraC. Multiple mechanisms, including the sequential emergence of overexpression of multidrug resistance-associated protein (MRP) and MDR1 genes, are involved in the cross-resistance of tumor cells to HHT.

Glutathione-S-transferases pi, alpha, mu and mdr1 mRNA expression in normal lymphocytes and chronic lymphocytic leukemia

Chronic B cell lymphoproliferative disorders are frequently sensitive to alkylating agents. To assess the glutathione-S-transferases (GSTs) gene expression in B tumoral lymphocytes, possibly responsible for this sensitivity, we developed a sensitive RT-PCR assay for the three isoenzymes GST pi, GST mu and GST alpha mRNA. Normal B and T lymphocytes from 11 blood donors were separated by magnetic beads and tested with this assay. The GST pi was the most abundant transferase, and was detected in all B and T cell samples. GST mu was undetectable ('null' phenotype) in 6/11 normal donors, either in B or T cells. GST alpha was very stable from donor to donor, and was highly correlated between B and T cells of the same individual (P < 0.0001). There is no correlation between the three isoenzymes, and between each isoenzyme and mdr1 gene expression. Twenty-three B lymphoproliferative disorders (20 B-CLL, 3 CD5- chronic lymphoproliferative syndromes) were tested with the same technique. An average decrease of 57% of the GST pi expression was noted in the mononuclear cells of these patients (P < 0.02), with no differences between the untreated and treated cases. The GST alpha and mdr1 mRNA levels did not differ from normal B lymphocytes, but the proportion of patients with no detectable expression of GST mu is lower than in the control (13%). Interestingly, the low content of GST pi in B-CLL could explain the frequent sensitivity of this disease to alkylating agents.

Expression of multidrug resistance-associated protein (MRP) and multidrug resistance (MDR1) genes in acute myeloid leukemia

The frequency, prognostic value and interrelation of MRP and MDR1 gene expressions were investigated by quantitative reverse transcription polymerase chain reaction (RT-PCR) in 91 cases of de novo acute myeloid leukemia (AML), of which 51 were newly diagnosed, 21 were relapsed, and 19 were refractory patients. As compared with normal bone marrow cells and peripheral granulocytes, an overexpression of MRP gene was found in 24% (22 of 91) cases of de novo AML. The incidence of MRP gene overexpression tended to be higher in relapsed patients than in newly diagnosed patients (38 vs 18%, P = 0.063). In 52 evaluable newly diagnosed and relapsed patients treated with MDR-related drugs, both MRP and MDR1 gene overexpressions correlated to a higher rate of emergence of clinical drug resistance (83 vs 22%, P = 0.005; and 67 vs 24%, P = 0.045, respectively). A positive correlation was found between MRP and MDR1 gene overexpressions (R = 0.53, P < 0.001). Analysis of 46 evaluable MDR1-negative cases revealed a trend for higher resistant disease rate in MRP-positive patients as compared with MRP-negative patients (100 vs 20%, P = 0.053). These data suggest that MRP, like MDR1, may have an important negative impact on the outcome of chemotherapy, and that there may be a common mechanism of induction for the overexpression of these two genes.

Overexpression of cyclin D2 in chronic B-cell malignancies

Tumor progression in B-cell chronic lymphocytic leukemia (B-CLL) is thought to result from the gradual accumulation of small resting G0/G1 phase lymphoid cells rather than the proliferation of actively dividing cells. The recent identification of G1 cyclins that are likely to control both the progression through G0 and G1 phase and the G1/S transition prompted us to study the mRNA expression of D-type cyclins in the peripheral blood lymphocytes from 34 patients with B-CLL, 7 patients with lymphoplasmacytic lymphoma (LPL), and 2 patients with mantle cell lymphoma (MCL). Cyclin D2 mRNA was, on average, 5- to 10-fold overexpressed in most of the samples studied (B-CLL, 29/34; LPL, 7/7; MCL, 0/2) as compared with normal resting B lymphocytes, in which cyclin D2 mRNA was barely detectable. In situ hybridization with cyclin D2 digoxigenin-labeled mRNA probe showed that all the cells from a given sample were stained with approximately the same intensity. Cyclin D3 was never detected in any of the samples tested, whereas cyclin D1 was expressed in only the 3 cases (1 LPL and 2 MCL) bearing a t(11;14) translocation. A trisomy 12 was found in 4 of 19 (21%) B-CLL or LPL cases for which cytogenetic analysis was available. Although the cyclin D2 gene has been mapped to chromosome 12p13, there was no apparent correlation between trisomy 12 and the level of cyclin D2 expression. Cell cycle analysis by flow cytometry after staining with propidium iodide consistently showed that more than 96% of the cells were in G0/G1 phase, whatever the importance of cyclin D2 overexpression was, and that cyclin D2 overexpression in B-CLL was not associated with any modifications of the cell cycle repartition. No consistent overexpression of cyclin D2 was found in acute myeloid leukemias. In conclusion, overexpression of cyclin D2 mRNA was found to be an almost constant feature in B-CLL and LPL. Therefore, it led us to hypothesize, with the support of data from some transfection experiments previously reported in murine hematopoietic cell lines, that cyclin D2 might play a role in B-CLL pathogenesis, possibly by preventing cells from programmed cell death.

P-glycoprotein in adult hematologic malignancies

The huge discrepancies in the proportion of tumors positive for P-gp observed in the literature limit any definite conclusions, except for the urgent need for standardized methods to compare results. It is well known by scientists that only positive results are published. For this reason, the frequency of P-gp expression in leukemia and lymphoma may be overestimated. The role of the MDR phenotype in clinical resistance is also not clearly demonstrated, because of the frequent association of other markers of bad prognosis on the same subset of cells (CD34, CD7 in leukemia). Hematologic malignancies are the most extensively studied tumors for drug resistance, and they could be a model for the therapeutic use of modifier agents. Many clinical trials are now ongoing in myeloma, acute leukemia, and lymphoma, with new modifier agents. The standardization of methods for P-gp, permitting large multicentric studies, and the results of randomized studies with modifier agents will help us know if mdr1 gene overexpression is of clinical importance in hematologic malignancies.

Over-expression of cyclin D1 in chronic B-cell malignancies with abnormality of chromosome 11q13

Accurate identification of B-cell chronic malignancies is sometimes uncertain, despite careful cytologic and immunophenotypic evaluation. Cytogenetics and molecular biology studies may therefore prove useful, because some of these disorders are associated with non-random abnormalities, such as the t(11;14)(q13;q32) translocation and bcl-1 rearrangement mainly observed in mantle-cell lymphoma (MCL). We studied the expression of cyclin D1 in malignant lymphoid cells from the peripheral blood of 32 patients with various B-cell chronic lymphoproliferative disorders, using Northern blot (NB) and RNA in situ hybridization (ISH). Cytogenetic analysis was informative in 18 cases, and most of the missing karyotype data were from typical B-CLL cases where a t(11;14) is unlikely to be found. Over-expression of cyclin D1 mRNA was observed by both NB and ISH in four samples (MCL; two cases; lymphoplasmacytic lymphoma: one case, unclassified B-cell chronic disorder: one case). In each of these cases there was an abnormality of chromosome 11q13, either a t(11;14)(q13;q32) translocation (three cases) or a del(11)(q13) without evidence of chromosome 14 involvement (one case). Cytogenetic and gene rearrangement studies are not available in all institutions and have some technical pitfalls. Because of its close association with bcl-1 rearrangement and/or t(11;14), the demonstration of cyclin D1 mRNA over-expression either by NB, or, more conveniently, by ISH, may represent additional information which could be of help for the identification of B-cell malignancies.

MDR-related P170-glycoprotein modulates cytotoxic activity of homoharringtonine

Homoharringtonine (HHT) is a new drug with antileukemic activity which is currently tested for treatment of acute and chronic leukemias, either alone or in combination with other agents. Since HHT showed a low efficacy in refractory and relapsed acute leukemia and in the blastic phase of chronic myeloid leukemia (CML) which are frequently characterized by an overexpresion of the multidrug resistance (MDR)-related P170-glycoprotein, we postulated a relationship between the poor antileukemic effect of HHT in these leukemias and the expression of P170-glycoprotein. For this reason, sensitive (LOVO109 and CEM) and MDR (LOVO DX and CEM VLB) cell lines were exposed to HHT with or without some MDR modifiers, namely, Cyclosporine A (CyA), the Cyclosporine derivative SDZ PSC 833 (PSC), and the D-isomer of Verapamil (DVRP). It was found that MDR cells were about 15 times more resistant to HHT than non-MDR cells, and that resistance to HHT was significantly decreased by all the MDR modifiers that were tested. This in vitro study showed that HHT belongs to the category of MDR-related drugs, like anthracyclines, vinca alkaloids, epipodophylline derivatives, and taxol.

[Piperacilline/tazobactam combination+amikacin versus ceftazidime+amikacin in patients with neutropenia and fever. An open multicenter study. Groupe d'étude des Aplasies Fébriles]

OBJECTIVES

To evaluate the toxicity and effectiveness of piperacillin+tazobactam and amikacin compared with a reference treatment with ceftazidime and amikacin given as first line therapy in neutropenic patients with fever.

METHODS

A multicentric randomized trial was conducted in 222 adults who had fever (38 degrees C for > 3 h) during a period of aplasia (white cell count < 0.5.10(9)/l for 22.9 +/- 10.4 days) induced by chemotherapy for acute leukaemia (68.1%) or by bone marrow autograft for lymphoma, myeloma or solid tumour (30.3%). 109 patients were assigned to the piperacillin (12 g/d)/tazobactam (1.5 g/d)+amikacin group and 113 to the ceftazidime (3 g/d)+amikacin group. Evaluation criteria were the frequency of apyrexia after a 72-hour antibiotic regimen and major infectious events defined as death due to infection and severe infections causing a delay in the chemotherapy protocol.

RESULTS

Data obtained in 188 patients who fulfilled all the protocol criteria were evaluated. The episode of fever was controlled better with the piperacillin/tazobactam+amikacin combination (apyrexia achieved in 60.6% of the patients vs 44.7% in the ceftazidime+amikacin group, p = 0.028) and there were fewer superinfections (23% vs 41% respectively, p < 0.008). Tolerance was similar in the two groups. In vitro, 56% of the strains resistant to piperacillin and isolated prior to treatment were sensitive to the piperacillin/tazobactam combination. Among the strains isolated (41 Gram-, 61 Gram+), 72% were sensitive to ceftazidime and 84% were sensitive to the piperacillin/tazobactam combination. There were 16 deaths due to infection (8.5%) with no difference according to antibiotic regimen. There was no difference in toxicity.

CONCLUSION

Tolerance was similar in the two groups. A combined regimen of piperacillin/tazobactam can be proposed as first line treatment for neutropenic patients with fever.

[Trials of modulating the MDR1 phenotype in malignant hemopathies]

The first trials with modifier agents and chemotherapy were conducted in myeloma, with verapamil and VAD. The objective responses observed could not be undoubtfully rapported to the addition of modifier agent. The cyclosporin A could be given at 10 to 18 mg/kg/d by IV route during few days, without nephrotoxicity. A bone marrow toxicity was due to the modification of cytostatic pharmacokinetics. The remissions observed with addition of cyclosporin A or quinine in acute leukemia could be due to either the high dose of ara-C given with daunorubicin or mitoxantrone, or to the drug pharmacokinetic modifications, or the P-gp inhibition on leukemic cells (or probably a combination of these factors). Randomized trials are now going on.

Evaluation of the clinical relevance of the anionic glutathione-s-transferase (GST pi) and multidrug resistance (mdr-1) gene coexpression in leukemias and lymphomas

By using RNA slot-blot technique, the frequency and the degree of GST pi and mdr-1 gene coexpression were investigated in 23 AML patients, 9 ALL, 9 CLL and 11 cases of NHL in an attempt to study their clinical and prognostic relevance. GST pi and mdr-1 levels were expressed as arbitrary units (U) with respect to the negative controls (U = 0), MCF7 and HL60 sensitive cell lines, and the positive controls (U = 10), MCF7/DOXO and HL60/DNR resistant cell lines. The concomitant GST pi/mdr-1 gene overexpression showed a negative prognostic value in the set of newly diagnosed AML pts (10 cases), furthermore higher GST pi and mdr-1 mRNA levels were averagely detected in the relapsed/resistant ALL pts (4 cases), and in CLL (7 cases) and NHL (8 cases) heavily pretreated patients who were unresponsive to chemotherapy and with a disease progression. These preliminary data show that two different mechanisms of drug resistance can be coexpressed at the same time in those leukemias and lymphomas with a clinically unfavourable course.

Early cytoreduction: a major prognostic factor in adult acute lymphoblastic leukemia

Prognostic factors in acute lymphoblastic leukemia (ALL) are used for treatment stratification of ALL. Definition of simple parameters such as the presence or absence of peripheral leukemic cells after one week of treatment could help for stratification. A retrospective study was conducted on 79 previously untreated adult patients with ALL followed in the Hematology department of Hotel Dieu from 1981 to 1991. 84% of patients achieved complete remission (CR), 7% were refractory to induction treatment, and 7 patients (9%) died during the first month after diagnosis. After multivariate analysis the only independent statistically significant factors for achieving CR were the absence of peripheral blast cells at day 7 (PBC D7) (p = 0.009) and age (< 50 years) (p = 0.03). For CR duration the same independent statistically significant factors were found (PBC D7 = 0 versus > 0, p = 0.008; and age < or > or = 30 years, p = 0.045). The PBC D7 value was more significant when circulating blast cells were present at diagnosis. In patients with more than 50,000 PBC at diagnosis, the 10- years event free disease was 62% +/- 20% when PBC were absent at day 7 versus 0% when PBC were present (p < 0.002). All 20 patients with prolonged DFS had PBC D7 = 0 achieving CR by 28 days. The persistence of PBC at Day 7 could be used as a factor to identify a subgroup of poor prognosis adults with ALL.

Flow cytometric monitoring of anthracycline accumulation after anti-neoplastic ether phospholipid treatment

Ether phospholipids are new anti-neoplastic drugs that have been found active against a variety of tumor cell lines, including drug-resistant sublines. We have characterized the antiproliferative activity of three ether phospholipids, i.e. ET-18-OCH3 (Edelfosine), BM 41.440 (limofosine) and a new aza-derivative (BN 52205), on three leukemic cell lines, i.e. K562 (chronic myeloid leukemia, blast crisis), HL60 (promyelocytic acute leukemia) and CEM (T cell leukemia), and their respective drug-resistant sublines, i.e. K562-ADR (adryamicin resistant), HL60-DNR [daunorubicin (DNR) resistant] and CEM-VLB (vinblastin resistant). These resistant sublines have been found to express the multidrug-resistant phenotype, revealed by the presence of the P-glycoprotein (PgP) using different monoclonal antibodies. Increased cellular accumulation of the fluorescent anthracycline has been found in both sensitive and resistant cell lines after different ether phospholipid treatment times. In resistant cells, the ether phospholipid effect on DNR accumulation has also been found after blocking the PgP function by verapamil and cyclosporin A. These results confirm that the ether phospholipid action is closely linked with the membrane biochemical composition and that these new anti-tumor drugs are able to change the dynamic structural organization of the tumor cell membrane.

Coexpression of anionic glutathione-S-transferase (GST pi) and multidrug resistance (mdr1) genes in acute myeloid and lymphoid leukemias

By using RNA slot-blot technique the frequency and degree of GST pi and mdr1 gene coexpression was investigated in 23 patients with acute myeloid leukemia (AML), and nine patients with acute lymphoid leukemia (ALL). With respect to the negative controls, MCF7 and HL-60 cell lines, increased GST pi and mdr1 mRNA levels, expressed as arbitrary units (U), were respectively detected both in AML and in ALL patients. A positive and significant correlation between GST pi and mdr1 gene expression was found in the group of AML patients, while in the smaller group of ALL patients only a trend could be shown. These data show that two different mechanisms of drug resistance can be coexpressed at the same time in patients with acute myeloid and lymphoid leukemia. From this evidence many important clinical and therapeutic questions arise.

[Pregnancy and hematologic malignancies: a therapeutic approach]

Pregnancy coexisting with evolutive malignant blood disease (Hodgkin's disease, acute leukemia, non-Hodgkin's lymphoma, chronic myeloproliferative disorder) is a therapeutic dilemma because of possible adverse reactions associated with the use of cytostatic agents. Therapeutic abortion, when needed, must be proposed only after a careful evaluation of the following parameters: the emergency of treatment, the prognosis of the disease, the term of pregnancy, the risks of therapy for the foetus and the mother, and the psychosocial context. From the clinical data published so far, the teratogenicity of cytostatic drugs seems to be minimal after the second trimester, and the outcome of pregnancy is often favorable, whatever the hemopathy. Radiation therapy must be used very cautiously and only in supradiaphragmatic areas. An overview of specific problems is done for each category of malignant blood disease.

Mdr1 gene expression in childhood acute lymphoblastic leukemias and lymphomas: a critical evaluation by four techniques

Expression of the multidrug resistance gene mdr1 is reported to be an important determinant of responsiveness to therapy and survival in some cancers. Many different methods have been used to evaluate mdr1 expression in these studies. This paper compares four methods for determination of mdr1 expression. We studied the mdr1 gene expression in 36 freshly established cell lines from 28 children with acute lymphoblastic leukemia (16 T-ALL, six BCP-ALL, two B-ALL (L3), two biphenotypic leukemias, two Burkitt's lymphomas). Leukemic specimens were obtained at the time of diagnosis in 16 cases, and after chemotherapy in 20 cases. In all the samples, mdr1 mRNA was measured by slot blotting and reverse transcriptase polymerase chain reaction (rt-PCR), and the presence of the mdr1 product, P-glycoprotein, was detected by immunohistochemistry with the MRK-16 monoclonal antibody. In situ mdr1 RNA hybridization was performed in 30 cases. Complete agreement was noted between all the techniques in 14 cases (39%). Results differed on a single test result in another 39% of the cases. These 78% of cases were considered assessable, and the consensus result was presumed to be correct. By this consensus criterion, immunohistochemistry yields both false negative (11%), and false positive (11%) results. RNA slot blotting has a high (21%) false positive rate. In situ mRNA hybridization and rt-PCR have the highest concordance, 80%. The 28 patients from whom these cell lines were derived appear to represent a very poor prognosis group, since there are only two patients (with Burkitt's lymphoma) who are long-term survivors. Nonetheless, a complete clinical response to therapy was correlated with absence of mdr1 expression in assessable cases (p = 0.04). These four methods of determining mdr1 expression often yield discordant results. Therefore, the use of at least two methods for evaluating mdr1 expression is advisable. Rt-PCR is recommended because of its relative simplicity and specificity. This should be supplemented by a technique (immunohistochemistry or flow cytometry) able to detect heterogeneity of P-glycoprotein expression among cells.

Acute myelogenous leukaemia in the elderly: retrospective study of 235 consecutive patients

A retrospective analysis was performed on 235 elderly acute myelogenous leukaemia (AML) patients aged 60 years or more, consecutively admitted to a single haematological department during a 10-year period from 1980 to 1989. 46% of patients received only conventional induction chemotherapy. The rate of inclusion in EORTC cooperative clinical trials was significantly lower than for younger patients despite specific protocols proposed for the elderly since 1983, thus confirming the important selection bias of most published series on elderly AML patients. Compared with treatment results in patients < 60 years, complete remission (CR) rate was lower (33.3% v 65.4%, P < 0.0001), with a marked drop in patients older than 70, and induction death rate was higher (21.3% v 12.5%, P = 0.04). Intrinsic characteristics of leukaemic cells, especially expression of the MDR1 gene, in vitro growth of the leukaemic clonogenic cells and sensitivity to daunorubicin-(+)cytosine arabinoside, did not differ according to age, except that there was a higher incidence of previous myelodysplastic syndromes and a lower incidence of good prognostic cytogenetics in the elderly patients. Thus, treatment failure in elderly AML patients appears to be mainly due to host-related factors (especially performance status and age < or > or = 70 years), and to inadequate treatments. Some elderly patients may have been undertreated because of the planned anthracycline dose reduction, resulting in a higher rate of 'resistant' AML, i.e. patients surviving the induction period without entering into CR, than in younger patients (45.4% v 22.1%, P < 0.0001). 11 patients (4.7%) with untreated or 'resistant' AML survived more than 1 year, while receiving only supportive care. These slowly progressive AML patients were characterized by a good performance status, and lower circulating blast cells and bone marrow blast counts.

Expression of resistance genes in acute leukemia

To evaluate the frequency and the prognostic value of different mechanisms of drug resistance in acute leukemias, we investigated the expression of mdr1 by immunocytochemistry, mRNA slot blot or RT-PCR in 182 cases of adult acute myeloid and 37 cases of adult lymphoblastic leukemia. Before treatment, 39% of de novo AML, 38% of secondary AML, and 7% of de novo ALL exhibited a high level of mdr1 mRNA. After chemotherapy, the frequency of mdr1 gene expression in ALL raised dramatically to 60% (P < 0.005), while no significant change was found for AML cases. In 91 patients treated with MDR-related drugs, mdr1 gene expression was related to the failure of chemotherapy (P < 0.0001). The overexpression of multidrug resistance-associated protein (mrp) and anionic glutathione S-transferase (GST pi) was also investigated in 38 and 61 AML patients respectively. An overexpression of mrp gene was noted in 39% of the cases. For GST pi gene, the frequency of overexpression was 28%. A positive and significative correlation was found among mdr1, mrp and GST pi genes expression.

[Treatment of high malignancy lymphoma with intensive short-term chemotherapy using the MACOP-B regimen]

We present our results of a MACOP-B regimen in a series of 46 patients with high-grade NHL. The complete remission rate was 74% for patients with advanced stage disease. The excellent tolerance allowed this regimen to be given on an outpatient basis in the majority of cases. The median follow-up for the living patients is 28 months. Although some patients received additional treatment that could influence the results, the predicted DFS (disease-free survival) at 45 months of 57% compares favorably with the best results published so far with more toxic regimens.

In vitro effect of rGM-CSF on proliferation and maturation of leukemic cells from patients with acute myelogenous leukemia

We investigated the effect of rGM-CSF on the proliferation/differentiation balance of the leukemic cells maintained in liquid cultures during 7 days, from 16 patients with acute myelogenous leukemia (AML). Cell proliferation was measured by tritiated thymidine (3HT) incorporation, and by the plating efficiency (PE) observed after 7 days of culture. Differentiation was measured by the ability of cells to reduce nitroblue tetrazolium (NBT) and by the percentage of immature myeloid cells. After 7 days of culture without rGM-CSF, an increase of 3HT incorporation (p = 0.01 compared to control) was observed in 8 cases. In these patients, an absence of PE was noted in only one case. Among the 8 patients with decreased 3HT incorporation (p = 0.01 compared to control), 6 exhibited functional maturation (increase of % of NBT + cells, p = 0.01), and 4 showed no PE. Seven days exposure to 50 ng/ml rGM-CSF increased the leukemic cell proliferation in 9 cases, induced complete functional differentiation in 4, and enhanced the CFU-L recovery in 6 cases. These effects were mainly observed in the "proliferative" group, where 7 of the cases had an increase of 3H-T. However, two of the "non proliferative" cases were also stimulated by GM-CSF. An absence of proliferation was generally accompanied by functional maturation.

Daunorubicin uptake by leukemic cells: correlations with treatment outcome and mdr1 expression

The in vitro daunorubicin (DNR) cell uptake was investigated by flow cytometry in K562/DOX resistant cell line and in 42 patients with acute myeloid leukemia (AML). The proportion of cells able to take up DNR was higher in untreated patients (50% +/- 30) than in previously treated patients (31% +/- 31) (p = 0.04). We noted a good correlation (p < 0.001) between the drug uptake after exposure to 0.1 microM DNR and achievement of complete remission. Cyclosporin A (CsA, 1 microgram/ml) and verapamil (5 micrograms/ml), but not cefoperazone (10 mM), completely reversed (CsA) or partially reversed (verapamil) the DNR efflux from K562/DOX mdr1(+) cell line. CsA significantly increased (p < 0.01) the DNR uptake of fresh leukemic cells, but not consistently, with no relationship to mdr1 mRNA cellular level. This absence of correlation was explained by the fact that several patients with no mdr1 gene expression exhibited a low in vitro DNR uptake, showing that the MDR phenotype is not the only mechanism responsible for the alteration of DNR pharmacokinetics in AML.

Treatment of chronic myelogenous leukemia in blast crisis and in accelerated phase with high- or intermediate-dose cytosine arabinoside and amsacrine

Twenty-two patients (mean age 41 years) in blast crisis or accelerated phase (AP) of chronic myelogenous leukemia (CML) were treated with cytosine arabinoside (Ara-C) 500 mg/m2 [intermediate dose] or 1000 mg/m2 [high dose] twice a day for 6 days and amsacrine (AMSA) 120 mg/m2 for 3 days. Twenty-one cases were of myeloid type and one was a lymphoid BC. The mean duration of aplasia (neutrophils < 0.5 x 10(9)/l) was 21.5 days. Four patients (18%) died of infection during aplasia and minor toxicities were noted for the remainders. Nine patients (41%) achieved a complete remission (CR) and 4 (18%) a partial response. Various additional therapies were proposed after induction treatment including allogeneic bone marrow transplantation (2 patients), Ara-C and AMSA maintenance or other regimens with or without alpha-interferon (9 patients). Median survival for the entire cohort was 20 weeks (wks), significantly superior for complete responders (37 wks) than for others (7 wks) (p = 0.008). In this study, age, sex, initial platelet or basophil counts, interval between diagnosis of CML and blast crisis were not predictive of response. Although inducing a high CR rate and associated with acceptable toxicity, this regimen did not improve the survival of patients with BC or CML, strengthening the need for alternate approaches to be defined.

Effect of differentiating agents on modulation of MDR1 gene expression in multidrug-resistant hematopoietic HL60/DNR cell line

The phenomenon of multidrug resistance (MDR) is frequently encountered in clinical situations, and could contribute to the failure of chemotherapy in acute leukemia. Preliminary studies have suggested that MDR1 gene expression in normal hematopoietic stem cells might be downregulated during differentiation. In the present study, we induced a multidrug-resistant promyelocytic leukemia cell line, HL60/DNR, to myeloid differentiation by exposure to all-trans retinoid acid and dimethyl sulfoxide (DMSO). We found that HL60/DNR cells retained the ability to respond to the differentiation stimulus. However, although MTT assays revealed a slight decrease of IC50 in differentiated cells, neither efflux of daunorubicin (DNR), nor expression of P-glycoprotein (P-gp), nor quantity of MDR1 mRNA has been downregulated in differentiated cells. We can conclude, therefore, that MDR1 gene expression in this multidrug-resistant myeloid cell line is not modified by induction of its differentiation.

Cyclosporin A as a modifier agent in the salvage treatment of acute leukemia (AL)

Sixteen adult patients with relapsed (7 patients) or refractory (9 patients) acute leukemia received mitoxantrone (10 mg/m2 per day for 3 days) and etoposide (200 mg/m2 per day for 3 days) with escalating dose of cyclosporin A (CsA) from a loading dose of 2 mg to 6.5 mg/kg per 2 h followed by 3 days continuous infusion of 5-15 mg/kg per day. The major toxicities were stomatitis and prolonged aplasia, occurring for 15 mg/kg per day of CsA. Transient conjugated hyperbilirubinemia occurred in all patients, and was CsA dose-dependent (r = 0.7). Adequate serum levels of CsA (> 1 microgram/ml) were obtained in 3/6 patients treated with 10 mg/kg per day and 4/4 patients with 15 mg/kg per day. The pharmacokinetic of mitoxantrone showed an unusual increase of carboxylic metabolites, parallel to CsA levels. We observed six responses (two complete and four partial remissions), and eight resistances. Two patients died at days 3 and 8 from sepsis. Before treatment, 7/16 patients tested for P-gp with C219 were positive (> 10% positive cells). 3/6 responders were P-gp-positive. At time of leukemic regrowth, cells expressing P-gp before therapy reverted to P-gp-negative cells.

Treatment of relapsing and refractory adult acute myeloid leukemia according to in vitro clonogenic leukemic cell drug sensitivity

In an attempt to improve the results of treatment in patients with relapsing or refractory acute myeloid leukemia (AML), we conducted a pilot study using a two-drug salvage regimen according to the in vitro clonogenic leukemic cell (CFU-L) drug sensitivity. Fourteen patients were included in the study, 10 with relapsing and 4 with refractory AML. Drug exposure was assessed for daunorubicin, cytosine arabinoside, etoposide, mitoxantrone and amsacrine. The two drugs with the best inhibitory effect on CFU-L were selected for the treatment. A complete remission was achieved in only 4 patients and a partial remission in 3 patients. Although the number of patients is too small for appropriate statistical analysis and for a definite conclusion to be drawn, the observed response rate with directed therapy did not appear better than that expected from empiric salvage regimen.

Should vancomycin be used empirically in febrile patients with prolonged and profound neutropenia? Results of a randomized trial

OBJECTIVES

We conducted a randomized trial with ceftazidine alone or associated with amikacin or vancomycin to investigate the efficacy of the daily 3 g dosage of ceftazidime and the efficacy of monotherapy with ceftazidime and to determine if vancomycin should be added empirically.

METHODS

Patient inclusion criteria were: age over 10 years, therapeutically-induced neutropenia and fever for at least three hours above 38.5 degrees C in absence of a clear non-infectious aetiology. Patients were randomized into three groups: group C, ceftazidime alone 3 g/day; group CA, ceftazidime 3 g/day plus amikacin 15 mg/kg/day; or group C, ceftazidime 3 g/day plus vancomycin 1.5 g/day.

RESULTS

Results from one hundred and two episodes of fever were analyzed. The underlying diseases were haematological malignancies (89 patients) and solid tumours (13 patients). The median duration of neutropenia (< 0.5 x 10(9) PMN/L) was 18 days and the minimum duration of 7 days. The main criterion for the analysis of efficacy was the onset of a major infectious event, i.e. death related to documented or suspected infection and any infectious event considered life-threatening or hindering future treatment of the underlying disease. Eight (22%) patients in group C developed major infectious events compared with four (13%) in group CA and none in group CV (p < 0.01). Major infectious events were mainly due to Gram-positive organisms, particularly Streptococcus species.

CONCLUSION

We conclude that: 1) ceftazidime alone and in association with amikacin is effective in preventing Gram-negative major infectious events; and 2) vancomycin should not be added only when a Gram-positive infection is documented, but used empirically.

Granulocyte-macrophage colony-stimulating factor in association to timed-sequential chemotherapy with mitoxantrone, etoposide, and cytarabine for refractory acute myelogenous leukemia

Recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF), given intravenously 5 micrograms/kg per day, was administered on days 4-8 of timed-sequential chemotherapy (TSC) with mitoxantrone, 12 mg/m2 per day on days 1-3, etoposide, 200 mg/m2 per day on days 8-10 and cytarabine, 500 mg/m2 per day on days 1-3 and 8-10, in 22 patients aged < 60 years with refractory acute myelogenous leukemia in an attempt to increase recruitment of leukemic cells in S phase before the second sequence of TSC. Thirty-eight patients treated with TSC without GM-CSF in a previous trial served as historical controls. In GM-CSF-treated patients, median duration of neutropenia < 0.5 x 10(9)/1 was 33 days and of platelet transfusion requirement 30 days, without any increase by comparison with controls. WHO grade 3 or more extra-hematologic toxicity included sepsis in 60% of patients, vomiting in 30%, diarrhea in 15%, hyper-bilirubinemia in 15%, and mucositis in 10%, without any difference with controls. Among 20 evaluable patients six individuals (30%), with a 95% confidence interval (CI) ranging from 12-54% achieved complete remission, 11 (55%, CI 31-77%) did not respond to therapy and three (15%, CI 3-38%) died from infection. There was no demonstrable in vivo proliferation of leukemic cells during the 5 days of administration of GM-CSF. The average percentage of bone marrow cells in S phase in five patients was 4.0 +/- 2.8 on day 4 and 7.0 +/- 7.2 on day 8 (p = NS). In this cohort of patients refractory to cytarabine, addition of GM-CSF did not increase efficacy of TSC by comparison with historical controls.

Cyclin A expression in human hematological malignancies: a new marker of cell proliferation

Several in vitro studies have shown that the cyclin A gene is expressed and plays an important role in both the S and G2-M phases of the cell cycle. We analyzed cells from the blood and bone marrow of patients with various, mostly neoplastic, hematological disorders to determine whether (a) the cyclin A protein level correlated with that of cyclin A RNA and (b) cell distribution among the different phases of the cell cycle correlated with cyclin A RNA expression. Thirty-eight patients were studied by means of dot blot and Western blot techniques for cyclin A RNA and protein accumulation, and 21 were also studied for cell cycle distribution by using flow cytometric analysis. Semiquantitative studies were based on densitometric computerized evaluation of dot and Western blots. There was a very strong positive correlation between cyclin A RNA and protein expression (r = 0.99; P < 0.00005), indicating that cyclin A accumulation is regulated in these cells at a transcriptional level. There was also a highly significant positive correlation between cyclin A RNA expression and the cumulative percentage of cells in S plus G2-M phase (r = 0.98; P < 0.00005). Therefore, this in vivo study shows that the expression of cyclin A RNA and protein in human hematological malignancies correlates with the percentage of cells in S plus G2-M phase and identifies cyclin A as a new potential cell proliferation index in oncology.

[Management of caustic burns of the esophagus in children]

The authors describe their therapeutic approach to caustic burns of the esophagus in pediatric patients. Initially, early endoscopic evaluation is carried out under general anesthesia using a stiff tube then a fiberoptic endoscope. During this procedure, severity of esophageal damage is determined: stage I: mild burn requiring no treatment; stages II and III: severe burn with a risk of subsequent esophageal stricture requiring insertion of a nasogastric stent. A repeat endoscopy is performed after approximately 25 days to evaluate healing. If healing has occurred, the nasogastric tube is removed and dynamic esophagography is performed 2 to 7 days later. Patients with strictures should be treated with repeated endoscopic dilatation at gradually increasing intervals. Surgery is indicated only in patients with complications or multiple strictures after failure of dilatation; trans-mediastinal colon esophagoplasty with removal of the burned esophagus is the method of choice.

[A program for medical use of information systems. Validity of calculation of direct costs for the initial treatment of acute myeloblastic leukemia]

In order to validate the information systems medicalization program used since 1984 at the Hôtel-Dieu hospital, Paris, the direct costs given by this program were compared with those calculated from the medical records of 10 adult patients hospitalized for diagnosis and treatment of acute myeloblastic leukaemia. The mean direct cost of an 8 to 81 days hospital stay was estimated at 75.393 +/- 41.260 French francs by the program and 84.969 +/- 52.288 FF by calculations from the records. A fairly good correlation (r2 = 0.72; P = 0.002) was found between the 2 evaluations. There was no statistically significant difference between the figures obtained by the 2 methods, except for pharmaceutical expenditures (P = 0.005) which were grossly underevaluated by the program. A better correlation could be obtained if an attribution of drugs and transfusions per patient was entered in the program.

Expression of multidrug resistance gene mdr1 mRNA in a subset of normal bone marrow cells

The multidrug resistance gene mdr1, encoding P-glycoprotein (P-gp), can be expressed at high levels in tumour cells derived from normal tissues with constitutive high expression of this gene. In myelogenous leukaemia, the incidence of increased expression of mdr1 gene contrasts with the low expression of this gene in normal bone marrow (b.m.). To detect cells expressing mdr1 gene in normal and post-chemotherapy b.m., we used in situ RNA hybridization and RNA phenotyping by the polymerase chain reaction for mdr1 mRNA detection. The presence of P-gp was evaluated by immunocytochemistry with MRK16. Fifteen b.m. (eight normal and seven post chemotherapy) were tested by in situ hybridization and either PCR (three b.m.) or immunocytochemistry (11 b.m.) or both (one b.m.). With in situ mRNA hybridization, a subset (7.7% +/- 3.1%) of b.m. cells expressed mdr1 mRNA in all cases tested, with no significant differences between normal b.m. and post chemotherapy b.m. 18% of myeloid recognizable cells and 7% of the cells with lymphoid morphology expressed mdr1 mRNA. By RNA phenotyping, the four samples tested for in situ hybridization and two additional post chemotherapy b.m. expressed mdr1. MRK16 was unable to detect a significant number of cells expressing P-gp either by immunocytochemistry in the 12 b.m. tested for in situ hybridization (0% in nine cases; 0.4%, 1% and 3% of positive cells in three cases), or by flow cytometry in six additional normal b.m. (0-1.4% positive cells).

Relevance of mdr1 gene expression in acute myeloid leukemia and comparison of different diagnostic methods

In an attempt to determine the incidence and clinical relevance of mdr1 gene expression in acute myeloid leukemia (AML), we examined 126 specimens obtained from adult patients with de novo AML by slot blot and immunocytochemistry. We found a high incidence of mdr1 gene expression in newly diagnosed patients (27% by immunocytochemistry and 43% by slot blot). No difference was observed between newly diagnosed patients and relapsed patients. However, patients with resistant disease showed statistically higher incidence of mdr1 gene expression compared to the untreated and relapsing patients (60% versus 27% by immunocytochemistry, p 0.005; and 73% versus 45% by slot blot, p less than 0.05). The expression of mdr1 gene correlated significantly with clinical drug resistance: 62% of patients positive for mdr1-mRNA and 68% of patients positive for P-glycoprotein (P-gp) eventually developed resistance to chemotherapy, while this was the case for a lower percentage of patients who did not express mdr1 gene (only 23% by slot blot analysis, p = 0.0052, or 24% by immunocytochemistry, p = 0.0009). A combined parameter, mdr1-mRNA/P-gp, had a very high prognostic value in terms of specificity and sensitivity. All nine patients (100%) who were mdr1-mRNA+/P-gp+ progressed to clinical drug resistance afterward, whereas 11 of 13 (85%) patients who were mdr1-mRNA-1 P-gp- entered complete remission and only two patients later developed drug resistance (p = 0.0005). It could thus be used as a reliable parameter in clinical settings.

Modulation of multidrug-resistant multiple myeloma by cyclosporin. The Leukaemia Group of the EORTC and the HOVON

Resistance to chemotherapy in refractory multiple myeloma is frequently associated with expression of multidrug resistance (MDR). In resistant cells, intracellular accumulation of doxorubicin and vincristine does not occur because the MDR-1 gene product, a membrane glycoprotein (PgP), is an energy-dependent efflux pump. Cyclosporin is one of several non-cytotoxic drugs that can block the function of PgP. In a prospective study, we assessed the possibility that cyclosporin could be used clinically to modulate MDR. We studied 21 patients with multiple myeloma; disease had progressed during primary chemotherapy in 6 and was resistant to VAD (vincristine, doxorubicin, dexamethasone) in 15. The patients received cyclosporin by continuous infusion during VAD treatment; there were three cyclosporin dosage groups (5, 7.5, 10 mg/kg daily). Serum cyclosporin concentrations adequate for MDR modulation were reached in all patients receiving 7.5 or 10 mg/kg daily. 47% (7) of the VAD-refractory patients and 48% (10) of the whole group responded to VAD. Before treatment, MDR-1 expression was present in 12 patients. After VAD plus cyclosporin, no MDR-1-positive plasma cells were present in 6 of 8 patients tested. The response rate in MDR-1-positive patients was 58% compared with 33% in all our patients. Toxic effects were mild and reversible and did not include nephrotoxic or serious cardiovascular side-effects. 12 months after the start of treatment, survival was 85%, and disease-free survival at a median of 9 months after the response was 65%. Thus, in multiple myeloma clinical resistance to VAD can be circumvented by cyclosporin, which enables the cytotoxic drugs to eliminate resistant myeloma cells.

Cost of complete remission induction in acute myeloblastic leukemia: evaluation of the cost-effectiveness of a new drug

The use of new drugs in the treatment of AML could dramatically increase the cost of induction chemotherapy. To evaluate the cost-effectiveness of such new drugs, the overall cost to achieve complete remission (CR) with treatments including these drugs has to be compared to the cost of the daunorubicin-cytosine arabinoside (DNR-AraC) association, considered as the reference treatment. A retrospective analysis of charts from 15 patients treated with DNR-AraC was used to identify 228 items of cost, including general cost, diagnostic, supportive care, and chemotherapy. Eleven patients underwent CR after one course of chemotherapy for a cost of US$16,701 +/- 4451, and four patients achieved CR after two courses for a cost of US$37,130 +/- 4923. The chemotherapy represented only 1.4% of the total cost, supportive care 25% and general cost 56%. According to these data, the projective cost of a treatment with mitoxantrone instead of DNR was simulated in 40 untreated patients with AML. The better rate of CR obtained after one course of chemotherapy leads to a saving of 9% (US$1261) per patient, despite the higher cost of chemotherapy. Cost-effectiveness evaluation should be included in the clinical study of trials with new drugs.