Leukaemia cell drug resistance and prognostic factors in AML.

In 93 cases of acute myeloid leukaemia (AML) the extent to which prognostic factors mirrored the in vitro cellular chemotherapy resistance (to anthracyclines aclarubicin (Acla) and daunorubicin (Dau) as well as nucleoside analogue cytarabine (Ara-C)) was investigated using a 4-d MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay. We found that age at presentation and presence of secondary AML were significantly correlated to leukaemia cell Ara-C resistance. Thus, analysis of in vitro drug resistance data revealed that age at presentation and presence of secondary leukaemia were both independently correlated to cellular drug resistance, with older age being associated with higher Ara-C resistance in vitro (p=0.02 and 0.01 in univariate and multivariate analyses, respectively) and with secondary leukaemia being associated with higher Ara-C resistance (p=0.04 and 0.059 in univariate and multivariate analysis, respectively). Median LC-50 values (Ara-C) were: 178 ng/ml in paediatric cases, 356 ng/ml in younger adult cases, and 584 ng/ml in elderly (age > or = 60 yr) cases giving a resistance ratio between these age subgroups of 1:2.0:3.3. Median LC-50 values (Ara-C) was 381 ng/ml in de novo cases as opposed to 891 ng/ml (resistance ratio 1:2.3) in secondary cases. By contrast, cytogenetic findings, presenting leucocyte count, FAB-subtype, and gender were not consistently correlated to in vitro drug resistance to any of the three drugs. We conclude that at least two major adverse prognostic factors in AML (advanced age at presentation and presence of secondary leukaemia) are associated with increased leukaemia cell Ara-C resistance. High leucocyte count is not associated with increased cellular drug resistance towards Acla, Ara-C or Dau.     

MDR1 gene expression and drug resistance of AML cells

We investigated the cellular drug resistance to aclarubicin (Acla), cytosine arabinoside (Ara-C), daunorubicin (Dau), doxorubicin (Dox), etoposide (Etop) and mitoxantrone (Mitox) using the MTT assay at time of disease presentation in 93 cases of acute myeloid leukaemia (AML). In 31 cases we concomitantly investigated MDR1 (multiple drug resistance 1 gene) expression (semi-quantitative competitive RT-PCR) of the leukaemic cells. Drug resistance towards Dau, Dox and Etop was correlated to the MDR1 expression of the AML cells ( P  < 0.05) with high MDR1 expression being associated with high drug resistance towards these drugs. Although the data did not allow firm conclusions to be drawn on the correlation between MDR1 expression and drug resistance towards Ara-C and Mitox, the drug resistance towards Acla clearly was not correlated to, or dependent on, the MDR1 expression level of the AML blast cells. In addition, when examining the cross-activities among the six drugs distinct patterns emerged. Thus, high to very high degrees of cross-activity were found to exist between Dau, Dox, Etop and Mitox, whereas Ara-C had moderate cross-activity with the other drugs except Acla, which showed absent to moderate cross-activity with the other drugs. We conclude that MDR1 gene expression is of significance for cellular drug resistance towards specific (MDR1-related) drugs in AML, whereas it is not of significance regarding drug resistance towards other drugs, which is the case with the anthracycline Acla. We suggest that in the place of other more or less complicated ways to circumvent MDR1-mediated drug resistance, Acla may be used to replace Dau, Dox and other MDR1-related drugs if proven as potent as the drug it is to substitute.     

IN VITRO RESISTANCE TO CYTOSINE ARABINOSIDE, NOT TO DAUNORUBICIN, IS ASSOCIATED WITH THE RISK OF RELAPSE IN DE NOVO ACUTE MYELOID LEUKAEMIA

The efficacy of chemotherapy in acute myeloid leukaemia (AML) is limited by clinical drug resistance. We determined in vitro resistance to cytosine arabinoside (ARA-C), daunorubicin (DNR), mitoxantrone (MITOX), m-amsacrine (AMSA) and etoposide (VP16) in 49 adults with de novo AML using the MTT assay. Results showed that non- responders to chemotherapy were, in vitro , 2.9-fold more resistant to DNR, but not more resistant to ARA-C, compared to complete responders. However, complete responders who were in vitro resistant to ARA-C had a 4-fold higher risk of relapse (95% CI 1.3–12.5-fold) compared to complete responders in vitro sensitive to ARA-C. With a mean follow-up of 12 months the probability of continuous complete remission (CCR) for patients in vitro sensitive to ARA-C was 61% at 34 months (95% CI 28–82%), whereas all patients in vitro resistant to ARA-C relapsed within 18 months from diagnosis. This difference appeared to be independent of other clinical features such as sex, age, white blood cell count, FAB classification, and CD34 expression. In vitro resistance to DNR was not related to the probability of CCR. We conclude that in vitro drug resistance assessed with the MTT assay appears to be associated with short- and long-term clinical outcome in AML. Confirmatory studies comprising a sufficient number of patients for multivariate analyses should prove whether in vitro resistance to ARA-C will appear to be an independent risk factor.     

Factors affecting the outcome of allogeneic bone marrow transplantation for adult patients with refractory or relapsed acute leukaemia

We evaluated the outcome of allogeneic bone marrow transplantation (BMT) for advanced acute myeloid leukaemia (AML) and acute lymphoblastic leukaemia (ALL) in 383 adult patients in nine Australian adult BMT centres between 1981 and 1997. The median overall survival for the group was 4.8 months, with an estimated 5-year survival of 18%. 28% of patients died of transplant-related toxicities within the first 100 d. Progressive disease was responsible for 48% of deaths. Multi-factor analysis demonstrated that AML (v ALL), disease status (second complete remission [CR2] v others), age (< 40 years) and duration of prior first complete remission (CR1) (> 6 months) were pre-transplant variables significantly associated with improved survival. Acute graft-versus-host disease (GVHD) of any grade reduced the rate of relapse in both AML and ALL, but only grades I-II were associated with improved survival. Both limited and extensive chronic GVHD were associated with increased survival. Only patients with AML in untreated first relapse or CR2, with a duration of CR1 > 6 months, or patients with T ALL, had a 5-year survival > 20%. Transplants for AML in induction failure or pre-B ALL in untreated first relapse or CR2 had an intermediate outcome, with 5-year survival of 10-20%. A 5-year survival of < 10% was observed for patients transplanted for ALL in induction failure or for pre-B ALL or AML in refractory first relapse or beyond CR2. These results suggest that for most adult patients with advanced acute leukaemia an allograft offers only a small chance of cure.     

Acute myelogenous leukaemia in older patients at St Bartholomew's Hospital: outcome with mitoxantrone and cytarabine

Elderly patients (age >60 years) with AML who are selected for curative treatment frequently receive anthracycline/cytarabine containing regimens. The anthracendione mitoxantrone (MTN) in combination with cytarabine (Ara-C) produces comparable complete remission rates to other regimens and may be less toxic. Over a 12 year period, 75 patients (median age 67 years, range 60-83 years) referred with newly diagnosed AML were treated with MTN and ara-C. MTN was administered at 12 mg/m(2)/day intravenously for three days in the first 26 patients, and 10 mg/m(2)/day intravenously for five days in a subsequent 49 patients. Ara-C was administered at a dose of 100 mg/m(2) twice daily intravenously for seven days. Complete remission (CR) was achieved in 34 out of 75 patients (45%). The median disease-free survival overall was 7.5 months (one month to nine and a half years). The median survival was one year for patients in whom CR was achieved, compared to four months in patients whom treatment failed (P=0.001). Age alone was predictive of achievement of CR, whilst presentation karyotype, serum LDH and patient age correlated with overall survival. These results confirm that although elderly patients have a poor outcome, prognostic factors can be identified that influence treatment outcome in this important group of patients.     

High-dose cytosine arabinoside and amsacrine or mitoxantrone in relapsed and refractory acute myeloid leukaemia: a prospective randomized study

52 patients with refractory or relapsed acute myeloid leukaemia (AML) were randomly assigned to receive a combination of high-dose cytosine arabinoside (HD Ara-C), 3 g/m2/d and either mitoxantrone (MTX), 7 mg/m2/d (5 mg if older than 60 yr) or m-amsacrine (AMSA), 120 mg/m2/d (90 mg if older than 60 yr) for 5 d. The overall response rate was 50% and did not differ significantly in the two groups (46% for AMSA and 56% for MTX, p = 0.415). The median survival was 11 months (8 months for AMSA and 12 months for MTX, p = 0.326) and the median duration of complete remission (CR) was 11 months for AMSA and 12 months for MTX (p = 0.643). In relapsed patients, the only significant predictive factor for obtaining a complete response was the length of first complete remission. Patients with a first CR shorter than 6 months had a CR rate of 36% while it was 65% if the first CR lasted more than 6 months (p = 0.03). Severe (WHO grade III-IV) gastro-intestinal toxicity was more frequent in the AMSA group (27% vs 4%, p = 0.021). Treatment-related death occurred in 4 patients in the AMSA group and in 2 patients in the MTX group (p = 0.097). We conclude that neither of these two treatment modalities was shown to be superior in terms of CR rate and survival, with a better tolerance for MTX.     

Treatment of de novo acute myeloid leukaemia in Hong Kong: a twenty-year experience (1975 to 1996)

Background : Small patient numbers and short follow-up are common in some acute myeloid leukaemia (AML) studies and data on secondary malignancies after treatment of AML are rare.
Aims : To determine the prognostic factors and long-term treatment results.
Methods : A retrospective study of patients with de novo AML under the age of 60 over a 20-year period in which two induction therapy regimens: 7:3 (1975–1983) and 7:3:7 (1984–1996) and three consolidation chemotherapy regimens: 5:2 (1975–1983), 5:2:5 (1984–1990) and Ara-C/mitoxantrone (1991–1996) were used. Disease-free (DFS), overall survivals (OS) and prognostic factors were analysed.
Results : Two-hundred and two of 276 (73%) patients attained complete remission (CR). The CR rates of 7:3 and 7:3:7 regimens were 70.5% and 74.5% respectively ( p =0.92). The median DFS was 12 months and the projected DFS at 10- and 20-years were 23% and 21% respectively. For patients consolidated with 5:2, 5:2:5 and Ara-C/ mitoxantrone, the median DFS was 15 m, 12 m and 11 m respectively and the projected ten-year DFS were 27%, 21% and 18% respectively ( p =0.2). Ninety per cent of relapses occurred within two years from remission but there were two late relapses at 109 m and 120 m respectively. Young age and FAB M3 subtype were favourable prognostic factors to OS ( p =0.04) and DFS ( p =0.006) respectively. There was no secondary solid tumour in the long-term survivors.
Conclusion : Our experience confirmed the efficacy of standard-dose Ara-C/daunorubicin and the prognostic value of age and FAB subtype. Median and projected DFS were similar to western studies.     

High-dose cytarabine in upfront therapy for adult patients with acute lymphoblastic leukaemia

Summary. In this national study, we have evaluated a new intensive chemotherapy protocol for adult patients with untreated acute lymphoblastic leukaemia (ALL). One hundred and fifty-three patients with median age 42 years received induction therapy with high-dose cytarabine (Ara-C), cyclophosphamide, daunorubicin, vincristine and betamethasone. A high complete remission (CR) rate (90%) was achieved in patients < 60 years compared with 70% in patients > 60 years ( P  = 0·004). The estimated 3 year overall survival for all patients was 29% (CI 21–36%) and the estimated continuous complete remission (CCR) at 3 years for the patients achieving CR according to the protocol was 36% (CI 27–45%). A favourable pretreatment characteristic was pre-B phenotype, especially for patients < 40 years without any high-risk factor, with an estimated CCR at 3 years of 62% (CI 41–82%). Stem cell transplantation (SCT) as post-remission therapy, mainly for high-risk patients, gave an estimated 3 year disease free survival (DFS) after SCT of 39% (CI 24–54%). No significant differences in DFS could be found between autologous, related or unrelated donor transplantation. We conclude that this intensive protocol resulted in a high CR rate combined with acceptable side-effects and a favourable CCR for patients with pre-B ALL.     

Continuous complete remission in adult patients with acute lymphocytic leukaemia at a median observation of 12 years after autologous bone marrow transplantation

We report our long-term experience with autologous bone marrow transplantation (ABMT) for 32 adult patients with acute lymphocytic leukaemia (ALL) in second or later remission (CR), or in first CR but with high-risk. Bone marrow was purged with mafosfamide (n = 25) or with immunomagnetic beads and monoclonal antibodies (n = 7). Retrospective analysis showed that 12 out of 32 patients were in continuous complete remission (CCR) at a median of 143 months (range 66-181 months). A plateau was reached at 50 months and the disease-free and overall survival rates were both 37.5%. It was notable that durable CCR could be achieved for patients in second (three out of nine) or third (one out of six) CR. ABMT could produce durable CCR and the long-term outcome compared favourably with those reported for allogeneic transplantation.     

Impaired glucose tolerance after autologous bone marrow transplantation

In this study we investigated glucose tolerance in relation to autologous bone marrow transplantation (ABMT). In 13 adult patients with acute myeloblastic (AML) or lymphoblastic (ALL) leukaemia in complete remission (CR), intravenous glucose tolerance test (IVGTT) was performed 1 month before and 6 months after ABMT. Patients with AML in CR received, as myeloablative therapy, cyclophosphamide combined with busulphan or total body irradiation (TBI). ALL patients received total body irradiation in combination with vincristine, daunorubicin, Ara-C, cyclophosphamide and prednisone. Before ABMT all patients, in spite of the intensive chemotherapy given for remission induction and consolidation, had a normal glucose tolerance. However, 6 months after the transplantation the k-value (rate of glucose elimination) for this group of patients had decreased (p less than 0.01). The trend towards impaired glucose tolerance was correlated with lower peak insulin values during IVGTT (p less than 0.05). Thus, the myeloablative therapy in connection with ABMT caused an impairment of pancreatic beta-cell function. No patient has hitherto developed clinical diabetes mellitus.     

Multicentre phase III trial on fludarabine, cytarabine (Ara-C), and idarubicin versus idarubicin, Ara-C and etoposide for induction treatment of younger, newly diagnosed acute myeloid leukaemia patients

Fludarabine plus cytarabine (Ara-C) and idarubicin (FLAI) is an effective and well-tolerated induction regimen for the treatment of acute myeloid leukaemia (AML). This phase III trial compared the efficacy and toxicity of FLAI versus idarubicin plus Ara-C and etoposide (ICE) in 112 newly diagnosed AML patients <60 years. Fifty-seven patients received FLAI, as the first induction-remission course, and 55 patients received ICE. Post-induction treatment consisted of high-dose Ara-C (HDAC). After HDAC, patients in complete remission (CR) received a second consolidation course (mitoxantrone, etoposide, Ara-C) and autologous stem cell transplantation (auto-SCT) or allogeneic (allo)-SCT, according to the age, disease risk and donor availability. After a single induction course, CR rate was 74% in the FLAI arm and 51% in the ICE arm (P = 0.01), while death during induction was 2% and 9% respectively. Both haematological (P = 0.002) and non-haematological (P = 0.0001) toxicities, especially gastrointestinal (i.e. nausea, vomiting, mucositis and diarrhoea), were significantly lower in FLAI arm. In both arms, relapses were more frequent in patients who were not submitted to allo-SCT. After a median follow-up of 17 months, 30% and 38% of the patients are in continuous CR in FLAI and ICE arm respectively. Our prospective randomised study confirmed the anti-leukaemic effect and the low toxic profile of FLAI as induction treatment for newly diagnosed AML patients.     

Biphenotypic acute leukaemia: a case series

Biphenotypic acute leukaemia (BAL) is a rare type of leukaemia. Whether patients with BAL should be treated with regimens designed for acute myeloid leukaemia (AML), acute lymphocytic leukaemia (ALL) or both remain unclear. We have reviewed the clinical data for 31 BAL patients. Most patients co-expressed B-lymphoid and myeloid markers. No specific chromosomal abnormality was identified. The majority of the patients were treated with regimens devised for treating ALL. Seven patients were treated with regimens designed for AML. Complete remission (CR) rates of 78% and 57% were noted respectively. The overall survival probability at 2 years was 60%.     

Magnetic resonance imaging of femoral marrow predicts outcome in adult patients with acute myeloid leukaemia in complete remission

Accurate assessment of residual disease is important for the prediction of outcome in patients with acute leukaemia in complete remission (CR). To investigate whether abnormalities on magnetic resonance (MR) images of femoral marrow in adult patients with acute myeloid leukaemia (AML) in CR can predict outcome, 28 newly diagnosed patients with AML underwent MR imaging when bone marrow aspiration or biopsy was performed to verify the state of CR after induction therapy. MR abnormalities on short TI (inversion time) inversion recovery (STIR) techniques persisted in all four patients who did not achieve CR. In 13 CR patients abnormalities on STIR images resolved, to result in normal appearance at the time CR was achieved. All 13 patients remained in CR for 3-104 months (median, 73 months). In the other 11 CR patients, STIR abnormalities persisted at the time CR was achieved. Seven of them relapsed between 1 and 28 months (median, 3 months) after MR evaluation. Disease-free survival of patients with persistent abnormal STIR images was significantly shorter than that of patients with normal STIR images (P < 0.01). MR imaging of femoral marrow may predict outcome in adult patients with AML in CR.     

MDR 1 expression is an independent prognostic factor for response and survival in de novo acute myeloid leukaemia

The Multidrug Resistance gene (MDR 1) is frequently expressed in acute myeloid leukaemia (AML). MDR 1 is associated with resistance to chemotherapy in vitro and with a poor response rate in AML. We have investigated the prognostic value of MDR 1 expression in relation to other patient characteristics with respect to response and survival.
One hundred and thirty patients aged 0–88 years were treated for de novo AML with standard induction and consolidation chemotherapy. MDR 1 expression was determined by immunocytochemistry. Univariate and multivariate analyses were conducted to identify prognostic factors for reaching complete remission (CR) and for overall survival from diagnosis, in order to compare MDR 1 with known prognostic factors. Univariate analysis showed that higher MDR 1 expression was an adverse prognostic factor for CR ( P  < 0.001), as was higher age ( P  < 0.001) and unfavourable karyotype ( P  < 0.01). These factors were also negative prognostic factors for overall survival ( P  < 0.001, P  < 0.05 and P  < 0.005, respectively). In the multivariate analysis MDR 1 ( P  < 0.001), higher age ( P  < 0.001) and karyotype ( P  < 0.01) were independent adverse prognostic factors for CR as well as for overall survival ( P  < 0.001, P  < 0.005, P  < 0.001, respectively). Our data indicate that MDR 1 expression is a disease-related unfavourable prognostic factor which has a significant impact on complete remission and overall survival in AML. Analysis of MDR 1 may be used to determine prognosis in individual patients.     

Contrasting in vitro effects for the combination of fludarabine, cytosine arabinoside (Ara-C) and granulocyte colony-stimulating factor (FLAG) compared with daunorubicin and Ara-C in P-glycoprotein-positive and P-glycoprotein-negative acute myeloblastic leukaemia

It has been suggested that the FLAG remission induction regimen comprising fludarabine (F-ara), cytosine arabinoside (Ara-C) and granulocyte colony-stimulating factor (G-CSF) may be capable of overcoming P-glycoprotein (P-gp)-related multidrug resistance (MDR) in patients with acute myeloblastic leukaemia (AML). We have investigated the in vitro response of P-gp-positive and -negative AML clones to FLAG and compared this with their response to treatment with Ara-C and daunorubicin (DNR). Twenty-four cryopreserved samples from patients with AML were studied using a flow cytometric technique for the enumeration of viable (7-amino actinomycin D negative) cells. Samples consisted of 12 P-gp-positive and 12 P-gp-negative cases, as measured by the MRK16 antibody. The results were analysed by calculating the comparative drug resistance (CDR), i.e. the percentage cell death caused by Ara-C + DNR subtracted from the percentage cell death, caused by FLAG after 48 h incubation in suspension culture. P-gp-positive clones were shown to have a significantly higher CDR than P-gp-negative clones (P = 0. 001). Furthermore, a significant positive correlation (r2 = 0.40, P < 0.01) was found between P-gp protein expression and CDR. However, P-gp function, measured using cyclosporin modulation of rhodamine 123 (R123) uptake, was not associated with the CDR, demonstrating that there are other properties of P-gp, besides its role in drug efflux, that modulate the responsiveness of AML blasts to chemotherapy. These results are consistent with a potential benefit for FLAG in P-gp-positive AML, but not P-gp-negative AML, compared with standard anthracycline and Ara-C therapy.     

Allogeneic haematopoietic cell transplantation for adult acute myeloid leukaemia in second remission: a retrospective study of the Adult Acute Myeloid Leukaemia Working Group of the Japan Society for Haematopoietic Cell Transplantation (JSHCT)

To evaluate the outcomes and prognostic factors following allogeneic haematopoietic cell transplantation (HCT) for adult acute myeloid leukaemia (AML) in second complete remission (CR2), we retrospectively analysed the Japanese registration data of 1080 adult AML patients in CR2 who had received allogeneic HCT. The probability of overall survival and the cumulative incidence of relapse at 3 years was 66% and 19%, respectively. In multivariate analysis, older age, poor cytogenetics and shorter duration of first complete remission were significantly associated with a higher overall mortality. Our data demonstrated the significant efficacy of allogeneic HCT for adult AML in CR2.     

Improved outcome after relapse in children with acute myeloid leukaemia

In the Nordic Society for Paediatric Haematology and Oncology paediatric study acute myeloid leukaemia (AML) 93, event-free survival was 50% and overall survival was 66%, indicating that many patients were cured following relapse. Factors influencing outcome in children with relapsed AML were investigated. The study included all 146 children in the Nordic countries diagnosed with AML between 1988 and 2003, who relapsed. Data on disease characteristics and relapse treatment were related to outcome. Sixty-six percentage achieved remission with survival after relapse (5 years) 34 +/- 4%. Of 122 patients who received re-induction therapy, 77% entered remission with 40 +/- 5% survival. Remission rates were similar for different re-induction regimens but fludarabine, cytarabine, granulocyte colony-stimulating factor-based therapy had low treatment-related mortality. Prognostic factors for survival were duration of first complete remission (CR1) and stem cell transplantation (SCT) in CR1. In early relapse (<1 year in CR1), survival was 21 +/- 5% compared with 48 +/- 6% in late relapse. For children receiving re-induction therapy, survival in early relapse was 29 +/- 6% and 51 +/- 6% in late. Patients treated in CR1 with SCT, autologous SCT or chemotherapy had a survival of 18 +/- 9, 5 +/- 5 and 41 +/- 5%, respectively. Survival was 62 +/- 6% in 64 children given SCT as part of their relapse therapy. A significant proportion of children with relapsed AML can be cured, even those with early relapse. Children who receive re-induction therapy, enter remission and proceed to SCT can achieve a cure rate of 60%.     

Inhibited apoptosis and drug resistance in acute myeloid leukaemia

Despite extensive investigation into mechanisms of drug resistance in acute myeloid leukaemia (AML), the aetiology of therapeutic resistance is unclear. We found that five leukaemia cell lines (K562, HL-60, CEM, CEM induced to overexpress bcl-2, and REH) displayed parallel sensitivity to four antileukaemia drugs with different mechanisms of action, with K562 generally being the least sensitive and REH being the most sensitive. The amount of spontaneous apoptosis in the cell lines after serum-free culture paralleled their drug sensitivity: K562 cells displayed the least apoptosis at 24 h (2.50 ± 0.24%) and REH the most (24.47 ± 8.22%). The extent of spontaneous apoptosis of leukaemic blasts from 39 patients with newly diagnosed de novo AML also correlated with the success of the intensive, infusional cytarabine-based induction therapy. There was a median of 19.5% (range 3.6–64%) apoptotic AML cells after 24 h of serum-free culture in patients who entered a complete remission compared with 4.2% (1.8–7.0%) apoptotic AML cells in patients who did not achieve a complete remission ( P  = 0.0007). Thus, inhibited apoptosis was associated with both in vitro and in vivo pan-resistance to antileukaemic chemotherapy. The cause of inhibited apoptosis in AML is probably a function of interactions among multiple signals that influence apoptosis. Assessment of spontaneous apoptosis may serve as an important prognostic factor for AML.     

P-Glycoprotein Expression in Acute Myeloid Leukaemia Cells at Diagnosis: Its relationship to Daunorubicin or Idarubicin Induction Therapy and Survival; Malignancy

We investigated the expression of P-glycoprotein (P-gp) in 50 adults with de novo diagnosed acute myeloid leukaemia (AML) and the relationship between presence of P-gp in leukaemic cells and efficacy, as remission induction and survival rate, of two different anthracyclines, daunorubicin (DNR) and idarubicin (IDR). We found that 30 out of 50 patients (60%) were negative (Group 1) and 20 (40%) were positive (Group 2) for P-gp expression evaluated by mean of MRK16 MoAb using a cut-off of 10% positive cells. Thirty-five out of 50 patients (70%) obtained complete remission (CR); depending on P-gp expression, the CR rate was 80% for group 1 and 45% for group 2 (p < 0.005). The median duration of overall survival was 20 months for patients in Group 1 as compared with 10 months for patients of Group 2 (p < 0.005). Regarding the anthracycline used, no significant difference in CR was observed in patients of Group 1 (75% of CR with DNR vs. 90% with IDR); Group 2 obtained 40% of CR with DNR vs. 70% with IDR (p < 0.005). The median duration of overall survival (OS) with the two regimens was comparable in Group 1, while it was significantly longer in patients of Group 2 treated with IDR compared with DNR regimen (p < 0.005). These results confirm the prognostic value of P-gp expression in AML at first appearance and we suggest that idarubicin could be a valid anthracycline drug in the treatment of AML to be evaluated as potential drug of choice in patients with primary or drug-induced multidrug resistance.     

Autologous bone marrow transplantation for patients with acute myeloid leukaemia and acute lymphoblastic leukaemia--a comparison

Forty-two patients with acute leukaemia were treated with autologous bone marrow transplantation (ABMT) using a combination chemotherapy protocol for bone marrow ablation. The response to high-dose chemotherapy and ABMT and its associated morbidity and mortality have been compared in 24 patients with acute myeloid leukaemia (AML) and 18 patients with acute lymphoblastic leukaemia (ALL). In 16 patients with AML treated with ABMT during first complete remission (CR), ten patients (62.5%) remain in unmaintained remission; median follow up is 32 months. In eight patients with ALL treated in first CR, only one remains in remission 32 months post-ABMT, with three patients dying non-leukaemic deaths. Fourteen of 18 patients (AML and ALL) treated after first remission have died of recurrent leukaemia, two died non-leukaemic deaths and two remain well 31 and 55 months post-ABMT; both have ALL. The length of hospital stay and the amount of blood product support were similar in both groups. Haematological recovery post-ABMT was delayed in patients with AML compared to patients with ALL but this difference was not significant. Rapidly progressive lung infection was thought to be the cause of four early deaths (4/18) in patients with ALL but none in patients with AML. Severe gram-negative infections were significantly more common in patients with AML.