Intensive postremission chemotherapy in adults with acute myeloid leukemia. Cancer and Leukemia Group B

High-dose chemotherapy in adult acute myeloid leukemia: rationale and results

Preclinical studies and retrospective evaluations of clinical trials of a number of cytotoxic drugs have provided a rationale for the use of high doses of chemotherapy in adults with acute myeloid leukemia (AML). To maximize cure and remission rates at an acceptable cost in toxicity, many schedules and combinations of dose-intensive chemotherapy have been tested in recent years in patients with de novo disease, cytosine arabinoside (Ara-C) being the most extensively evaluated drug. In this article we review the principal results of both randomized and non-controlled studies. Our analysis indicates that high-dose Ara-C (HIDAC) used during induction results is no substantial benefit relative to conventional doses of drug. On the other hand, consolidation with HIDAC is a major advance in the treatment of this disease. In fact, in individuals less than 60 years of age and a favorable or intermediate-risk karyotype, HIDAC-based regimens have resulted in survival estimates comparable to those of autologous or allogeneic bone marrow transplantation. Yet, the role of HIDAC is irrelevant in younger individuals with an unfavorable cytogenetic pattern and detrimental in patients greater than 60 years of age. Since recently new cytotoxic agents have expanded the armamentarium of antileukemic drugs, well conducted randomized trials of dose intensive chemotherapy still need to be performed to optimize schedules and combinations of drugs in patients with AML.

Acute pancreatitis associated with continuous infusion cytarabine therapy: a case report

BACKGROUND

While acute pancreatitis is a recognized complication of numerous drugs, cytarabine's role in causing this complication is controversial. Approximately 15 cases have been reported to the Food and Drug Administration linking cytarabine with pancreas-related toxicities. Previous case reports have been complicated by comorbid illnesses and the coadministration of other drugs associated with acute pancreatitis.

METHODS

This report describes the clinical course of a patient with acute myelogenous leukemia (AML) who developed recurrent pancreatitis associated with cytarabine therapy.

RESULTS

A male age 36 years with French-American-British M5B acute myelogenous leukemia received induction cytarabine (200 mg/m2/day) by continuous infusion for 7 days, and subsequently developed acute pancreatitis. The patient was rechallenged with intermittent, bolus, high dose cytarabine (HDAC) (3 g/m2bid administered over 3 hours) during the following intensification treatment, but did not develop clinical acute pancreatitis. Retreatment with continuous infusion cytarabine at a later time resulted in recurrence of acute pancreatitis.

CONCLUSIONS

This case illustrates that cytarabine treatment may cause acute pancreatitis, and that this toxicity may be schedule dependent. In those with known sensitivity to cytarabine, altering the administration technique may avoid this complication.

Intensive treatment of patients age 60 years and older with de novo acute myeloid leukemia: analysis of prognostic factors

BACKGROUND

This study aimed to define pre-treatment parameters with prognostic significance in elderly patients with de novo acute myeloid leukemia (AML) who were treated with aggressive regimens.

METHODS

We analyzed, retrospectively, the clinical and laboratory features of 159 consecutive patients age >60 years with AML. Ninety-two patients presenting as de novo AML were considered suitable for aggressive chemotherapy according to inclusion criteria not different from those commonly used for younger adults. They belonged to all of the French-American-British classification types except M3, and their median age was 67 years (range: 60-79). Antileukemic treatment consisted of 1 of 3 sequential protocols adopted at the S. Eugenio University Hospital of Rome between 1987 and 1993. The three therapeutic groups were similar in number and presenting characteristics. In addition to arabinosylcytosine, induction schedules included mitoxantrone (Groups I and II) or daunorubicin (Group III), and etoposide (Groups I and III). Once in complete remission (CR), patients were consolidated with two other courses of chemotherapy using reduced dosages of the same drugs given during induction.

RESULTS

Induction treatment achieved a 52.2% CR rate, with median remission duration and event free survival (EFS) of 35 and 27 weeks, respectively. Because no significant differences between the results of the three therapeutic groups were observed, all cases were pooled to evaluate the prognostic factors. In univariate analysis, the only presenting characteristic significantly associated with failure of induction treatment was age >67 years (P=0.007). Factors associated with an increased likelihood of shorter remission duration were CD7 expression on leukemic cells (P=0.007) and an abnormal karyotype (P=0.010; those predicting shorter EFS were a chromosomal status other than normal (P=0.002) and detection of CD14 antigen (P=0.008). Logistic regression results identified age and CD14 expression as the variables with independent prognostic impact on CR achievement. In a stepwise proportional hazards general linear model, CD7 and karyotype retained their predictive value regarding remission duration, whereas the karyotypic pattern at diagnosis and CD14 antigen expression were the most important determinants of EFS, with age showing a borderline statistical value. A simple "risk factor score" was developed that would allow for stratification of patients into prognostic groups.

CONCLUSIONS

Cytogenetic analysis and immunophenotyping might help to select elderly patients with AML who have little benefit from current therapeutic strategies and with whom new approaches might be experimented.

Bone Marrow Transplantation for Cancer—An Update

The number of allogeneic and autologous bone marrow transplants continues to grow worldwide. Bone marrow transplantation (BMT) has become standard therapy for many patients with leukemia, lymphoma, multiple myeloma and testicular cancer. Encouraging results of autologous BMT in treating patients with poor-risk breast cancer have led to this approach being tested in nationwide randomized trials. In order to increase availability and efficacy of BMT, other sources of hematopoietic cells are explored for transplantation, such as from HLA-matched unrelated volunteer donors, partially matched related donors, placental/umbilical cord blood and allogeneic peripheral blood. Relapse of original malignancy remains the main obstacle for the success of BMT. Recent clinical investigations have demonstrated that donor-derived peripheral blood leukocytes are effective in inducing remissions in patients with hematological malignancies who relapse after allogeneic BMT. BMT procedures are associated with significant complexity and should be carried out only in transplant units that meet adequate standards. In order to better define the role of BMT in treating cancer, more phase III clinical trials are needed. The future of BMT will depend on further improvements in its efficacy and economic constraints.

Treatment and prognostic factors in acute myeloid leukaemia

Current induction chemotherapy regimens afford a complete remission in 60 to 80% of patients less than 60 years of age who are diagnosed with acute myelogenous leukaemia. Patients who undergo consolidation with high dose Ara-C or with autologous or allogeneic bone marrow transplantation can expect a long-term disease free survival of 30 to 45%. Which mode of consolidation is preferable is still being investigated in randomized studies. Many disease characteristics have been put forward as prognostic variables in treatment outcome and as understanding of the biology of AML has continued to expand, cytogenetic and molecular markers have assumed greater importance in disease characterization, but the ultimate role that these play in prognosis remains incompletely defined. Once AML has relapsed, bone marrow transplantation may result in prolonged disease free survival as compared to use of salvage chemotherapy regimens. Because the long-term survival of all patients diagnosed with AML is only in the order of 10 to 20%, new treatment approaches to this disease are required. Current clinical and research efforts have focused on modulation of the immune system, modulation of drug resistance phenotypes, and understanding of the response of leukaemic cells to haematopoietic growth factors.

Treatment of the elderly patient with acute myeloid leukaemia

Individuals of 60 years living in western countries generally have a mean life expectancy of 20 years at least. Therefore, when aged individuals present with AML, it is a necessity and a challenge to treat them as efficiently as possible. AML is mainly a disease of the elderly and accounts for more than 50% of its incidence among the general population. The treatment of older individuals with AML has remained difficult and its success is still limited. While in adults with AML of less than 60 years complete responses above 65% and survival rates of 35% are commonly obtained, progress in the treatment of elderly patients has been relatively small. As of today, approximately 50% of older patients may be induced into remission with chemotherapy, and, among these complete responders, only approximately 1 in 10 will survive free of leukaemia beyond 4 years after diagnosis. In fact, on one hand, these results represent the rationale and motivation for offering chemotherapy to the older population. On the other hand, they emphasize that major obstacles to better cure rates still exist. These stumbling blocks apparently relate to the restricted tolerance of older subjects to the exposure of chemotherapy and probably also a greater probability of unresponsiveness of the leukaemia to cytotoxic therapy. The haematopoietic growth factors still hold some promise and may improve outcome, but for the time being there is insufficient direct evidence to indicate a defined and established role. It is evident that new avenues should be pursued and trials specifically designed for elderly people with AML be conducted. These trials would need to address questions related to the choice of chemotherapeutic drugs (e.g. idarubicin versus mitoxantrone), their dose and schedule selection, the use of multidrug resistance modulators (to overcome intrinsic drug non-responsiveness), and the optimal clinical use of haematopoietic growth factors, including thrombopoietin. Since trials addressing specific questions regarding the development of treatment of elderly patients with AML have remained scarce, the initiation of these studies is sorely needed. One may hope that these clinical trials will provide some of the necessary answers and new clues, and will be useful to advance future therapy of elderly AML patients.

Five year leukaemia-free survival of 72% and 77% for early stage acute and chronic myeloid leukaemia treated by HLA-identical sibling bone marrow transplantation

BACKGROUND

HLA-identical sibling bone marrow transplantation is an accepted treatment for patients with acute myeloid leukaemia (AML) and chronic myeloid leukaemia (CML). We have recently reported improving results in HLA-identical sibling transplant over the ten year period 1981-1990. In this report we described the outcome in patients transplanted at St Vincent's Hospital, Sydney between 1989 and 1993.

AIMS

To determine the leukaemia-free survival, transplant-related mortality rate, and relapse rate for patients with AML or CML given HLA-identical sibling marrow transplants between 1989 and 1993.

METHODS

Sixty-two patients with AML or CML received high dose busulphan/cyclophosphamide chemotherapy followed by infusion of T replete, HLA-identical sibling bone marrow. Cyclosporin/short methotrexate was utilised as prophylaxis for graft-versus-host disease, ganciclovir as prophylaxis for cytomegalovirus disease and cotrimoxazole as prophylaxis for Pneumocystis carinii pneumonia. Low dose intravenous heparin was used as prophylaxis for hepatic veno-occlusive disease.

RESULTS

The five year disease-free survival for patients with AML transplanted in first complete remission was 72% and for those with CML transplanted in first chronic phase was 77%. The relapse rate for AML transplanted in first complete remission was 15% and for CML in first chronic phase 0%. The transplant-related mortality for AML transplanted in first complete remission was 16% and for CML transplanted in first chronic phase 23%. In contrast, the disease-free survival, relapse rate and transplant-related mortality for patients with AML transplanted outside first complete remission and for CML transplanted beyond first chronic phase was 17%, 57% and 57% respectively.

CONCLUSIONS

The outcome for patients transplanted for early AML or early CML continues to improve and exceeds that obtainable by conventional therapy. The salvage rate is so low for patients transplanted in later stages of AML or CML that all patients less than 55 years of age with these diseases, who have a HLA-identical sibling donor, should be offered bone marrow transplantation early in their disease course.

The need for cytoprotection

The toxicity associated with chemotherapy is significant and dose limiting. Multiple organ systems can be affected, with both acute and chronic side effects producing adverse effects. The concept of cytoprotection, or the selective protection of normal tissues is a strategy now being investigated in preclinical and clinical models. Systemic approaches have included the use of compounds such as sodium thiosulphate, diethyldithiocarbamate and amifostine. The most promising results have been obtained with the organic thiophosphate compound amifostine (Ethyol, WR-2721).

Autologous bone marrow transplantation for acute myeloid leukemia

Despite progress over the past three decades, most patients with acute myeloid leukemia (AML) treated with conventional chemotherapy alone relapse and die of recurrent leukemia. Treatments used to improve outcome include allogeneic (alloBMT) and autologous bone marrow transplantation (ABMT). Indications for transplantation and the relative merits of alloBMT and ABMT remain unclear. In this review, we evaluate evidence supporting a role of ABMT in AML and compare the results with outcomes after alloBMT. In addition, we discuss areas of controversy including the optimal timing for ABMT, the role of bone marrow purging, the place of peripheral blood stem cell collection, the high dose regimen, and post-transplant immunotherapy to reduce relapse.

Postremission therapy with two different dose regimens of cytarabine in adults with acute myelogenous leukemia

Sixty-seven out of 105 (64%) adults with de novo acute myelogenous leukemia (AML), achieving complete remission after induction chemotherapy, entered two successive postremission treatment protocols. Between 1987 and 1989, 35 patients received an intermediate dose of cytarabine (IDAC) along with other drugs. Between 1990 and 1993, 32 patients received high dose cytarabine (HIDAC) with similar other drugs. Patients treated with IDAC had a median survival of 13.8 months (95% CI 11.2-23.1 months) and a 2 year survival of 34.3 +/- 8.0%. Patients receiving HIDAC had a median survival of 35.5 months (95% CI, lower limit 29.8 months) and a 2 year survival of 71.6 +/- 9.4% (P < 0.002). The 2 year actuarial leukemia-free survival (LFS) was 17.8 +/- 6.6% in the IDAC group and 67.3 +/- 10.0% months in the HIDAC group (P = 0.004). The HIDAC group had a significant 2 year survival advantage over the IDAC group only in patients younger than 45 years. The 2 year survival in the first group was 83.3 +/- 10.8% versus 23.5 +/- 10.3% in the IDAC group (P = 0.0001). In patients older than 45 years, no significant differences in 2 year survival was noticed (52.9 +/- 15.78 versus 44.4 +/- 11.7, P = 0.8). Censoring the 21 patients who underwent bone marrow transplantation (BMT) at BMT did not change significantly the survival analysis of the patients in each group. This study is consistent with previous reports favoring HIDAC intensification in the postremission treatment of young patients with AML.

MEC (mitoxantrone, etoposide and intermediate dose cytarabine): an effective induction regimen for previously untreated acute non-lymphocytic leukemia

Twenty-three patients with acute non lymphocytic leukemia (ANLL), were treated with a single-6 day course of Mitoxantrone 6mg/m2/day, Etoposide 80mg/m2/day and intermediate dose Cytarabine (ara-C) 1g/m2/day (MEC). Patients who achieved complete remission (CR) were submitted to a 4-day-course of MEC as consolidation. Seventeen patients (73.9%) obtained CR, five patients (22.7%) were resistant to the treatment and one patient died during induction. Median remission duration was 11 months; overall median survival was 16 months. Relapses occurred in 11 patients; eight patients are still alive: 6 in 1st, 2 in 2nd CR (mean survival 20.1 months, range 17-26). All patients experienced severe myelosuppression comparable to that observed after classical induction cycles including ara-C in continuous intravenous infusion; none, however, died of infection. Non-hematologic toxicity was minimal; in particular, neurotoxicity was not observed. According to our results, the MEC regimen, which was previously demonstrated to be active in refractory patients, represents an effective induction treatment in ANLL, with an acceptable toxicity.

High-dose cytosine arabinoside and daunorubicin postremission therapy in adults with de novo acute myeloid leukemia. Long-term follow-up of a prospective multicenter trial

A total of 149 consecutive de novo AML patients aged 50 years or less (median age = 37 years) were enrolled in this prospective multicenter trial initiated in May 1985. All patients received the same induction and early consolidation therapy with daunorubicin (DNR), cytosine arabinoside (Ara-C), and etoposide (DAV). High-dose Ara-C/DNR therapy included Ara-C at 3 g/m2, in 12 doses (HD-Ara-C/DNR I) and eight doses (HD-Ara-C/DNR II), followed by DNR 30 mg/m2 for 3 days. A complete remission (CR) was achieved in 104 (70%) patients; 61 complete responders received at least one cycle with HD-Ara-C/DNR. If those patients who were transplanted in first CR (n = 26), were not considered, the median relapse-free-survival (MRFS) of the remaining 78 patients was 15 months, with a probability of relapse-free survival (RFS) at 116 months of 30% (95% CI, 20-40%) after a median follow-up of 95 months. The MRFS of the HD-Ara-C/DNR consolidated patients was 25 months, with a probability of RFS at 116 months of 37% (95% CI, 24-50%). If all patients who were transplanted (n = 44) were not considered, the median survival time (MST) was 18 months with a probability of being alive at 118 months of 24% (95% CI, 16-33%). MST of the HD-Ara-C/DNR consolidated patients was 58 months with a survival probability of 46% (95% CI, 31-60%) at 118 months. Prognostic factor analysis did not reveal any significant influence of age, sex, FAB subtype, white blood cell count, hemoglobin level, thrombocyte count, LDH, or response to the first induction course on RFS of the HD-Ara-C/DNR consolidated patients. In summary, HD-Ara-C/DNR consolidation can improve the long-term outcome of a subgroup of de novo AML patients. Further improvement of the outcome seems to depend on the identification of patients with an inferior outcome under that strategy who might benefit from alternative treatment strategies.

Clinical pharmacology of cytarabine in patients with acute myeloid leukemia: a cancer and leukemia group B study

The pharmacokinetics of cytarabine (ara-C) were determined in 265 patients with acute myeloid leukemia (AML) receiving ara-C (200 mg/m2 per day for 7 days as a continuous infusion) and daunorubicin during induction therapy. The mean (standard deviation) ara-C concentration at steady-state (Css) and systemic clearance (Cl) were 0.30 (0.13) microM and 134 (71) l/h per m2 respectively. Males had a significantly faster ara-C Cl (139 vs 131 l/h per m2, P = 0.025) than females. Significant correlations were noted between ara-C Cl and the pretreatment, peripheral white blood cell count (P = 0.005) and pretreatment blast count (P = 0.020). No significant differences in ara-C Css or Cl were noted in patients achieving complete remission compared with those failing therapy (P = 0.315, P = 0.344, respectively). No significant correlations were observed between ara-C pharmacokinetic parameters and several indices of patient toxicity. Our findings indicate that variability in ara-C disposition in plasma at this dosage level does not correlate with remission status or toxicity in patients with AML receiving initial induction therapy with ara-C and daunorubicin.

Mitoxantrone and cytosine arabinoside as treatment for acute myeloblastic leukemia in older patients

The majority of patients with acute myeloid leukemia (AML) are elderly, and their response to chemotherapy is poorer than that of younger patients. The combination of mitoxantrone (MTN) and cytosine arabinoside (Ara-C) is a possible alternative to an anthracycline/Ara-C combination for the treatment of AML in these patients. Of 52 older patients (> 59 years) referred over a 3.5-year period, 33 patients (age range 60-78 years, median 67 years) received MTN and Ara-C as therapy for newly diagnosed AML. MTN was administered at a dose of 12 mg/m2/day, intravenously, for 3 days (23 patients), or 10 mg/m2/day for 5 days (10 patients), and Ara-C at a dose of 100 mg/m2 twice daily, intravenously, for 7 days. Complete remission (CR) was achieved in 16/33 patients (48%). The median remission duration was 6 months (range 1-37 months). The median survival was 14 months for those who achieved CR compared with 9 months for those with resistant disease. Two patients remain in first CR after 13 and 37 months, but three patients died whilst receiving consolidation therapy. In selected elderly patients with AML, the combination of MTN and Ara-C provides an acceptable alternative to an anthracycline/Ara-C regimen, with a higher CR rate than historical controls. However, the CR rate and remission duration remain low compared with those of younger patients, supporting the need to investigate new approaches to treatment in this population.

Granulocyte-macrophage colony-stimulating factor after initial chemotherapy for elderly patients with primary acute myelogenous leukemia. Cancer and Leukemia Group B

BACKGROUND

Elderly patients with primary acute myelogenous leukemia (AML) are less likely to enter remission than younger adults, in part because of a higher mortality rate related to severe myelosuppression. Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been shown to shorten the duration of neutropenia and decrease infectious complications when administered after chemotherapy to patients with lymphomas and solid tumors.

METHODS

We randomly assigned 388 patients 60 years of age or older who had newly diagnosed primary AML to receive placebo or GM-CSF (5 micrograms per kilogram of body weight per day intravenously over a period of six hours) in a double-blind manner, beginning the day after the completion of three days of daunorubicin (45 mg per square meter of body-surface area per day) and seven days of cytarabine (200 mg per square meter per day by continuous intravenous infusion). If leukemia cells persisted in the marrow three weeks after the initiation of chemotherapy, further daunorubicin (two days) and cytarabine (five days) were administered. GM-CSF or placebo was given daily until the neutrophil count was at least 1000 per cubic millimeter, there was evidence of the regrowth of leukemia, or severe toxic effects attributable to the study infusion occurred. Patients who had a complete remission were then randomly assigned to receive one of two intensification regimens.

RESULTS

Of 388 patients (median age, 69 years), 193 were randomly assigned to receive GM-CSF and 195 to placebo. The rate of complete remission was 51 percent (95 percent confidence interval, 44 to 59 percent) among those assigned to GM-CSF and 54 percent (95 percent confidence interval, 47 to 61 percent) among those assigned to receive placebo (P = 0.61). The reasons for failure (early death, death during marrow hypoplasia, and persistent leukemia), the incidence of severe or lethal infection, and the incidence of the regrowth of leukemia (2 percent overall) were similar in the two groups. The median duration of neutropenia was slightly shorter (P = 0.02) in the patients who received GM-CSF (15 days) than in those who received placebo (17 days), but the clinical importance of this result was minimal because the growth factor failed to lower the treatment-related mortality rate or improve the rate of complete remission.

CONCLUSIONS

GM-CSF, in the dose and schedule we used, does not stimulate the regrowth of leukemia, but it also does not decrease the severe myelosuppressive consequences of initial chemotherapy or improve the response rate in patients 60 years of age or older with primary AML. It should not be recommended for use in such patients.

Morphologic characteristics of erythroleukemia (acute myeloid leukemia; FAB-M6): a CALGB study

We have reviewed the clinical, morphologic, immunophenotypic, and cytogenetic features of 52 patients with erythroleukemia (FAB Cooperative Group; AML-M6) studied by the Cancer and Leukemia Group B (CALGB). The purpose of this study was to correlate morphology with the clinical features, immunophenotypes, and karyotypes of neoplastic cells, and with the response to therapy of patients with AML-M6. Thirty-three patients (63%) were male, median age 59 (range 16-81) years, 47 patients (90%) were white, and 42 patients (81%) had a performance status of < 2. Myelodysplastic changes were observed in at least 1 cell lineage in all cases, and in 2 cell lineages in 45 of 52 (86%) cases. Fifty percent or more of cases studied were positive for CD11b, CD13, CD15, CD33, glycophorin-A, and HLA-DR markers. Fourteen of 27 cases (52%) in whom karyotypic analyses were conducted had cytogenetic abnormalities. Five (19%) were simple (< 3 karyotypic abnormalities), while 9 (33%) were complex (> or = 3 abnormalities). We observed either a complete or partial loss of chromosomes 5, 7, or 12p, or the presence of trisomy 8, in 11 of 27 (41%) patients. Cases of AML-M6 were divided into group 1 (14 patients with bone marrow proerythroblasts and basophilic erythroblasts > 25% of all erythroblasts) and group 2 (38 patients with proerythroblasts and basophilic erythroblasts < or = 25% of all erythroblasts). We observed no significant differences between groups 1 and 2 in regard to sex, age, race, performance status, percentage of blood erythroblasts or myeloblasts, percentage of bone marrow erythroblasts, and periodic acid-Schiff (PAS) or myelodysplasia scores. Six of 6 (100%) patients of group 1, and 7 of 21 (33%) patients of group 2, had normal karyotypes (P = .006). Nine of 13 (69%) patients of group 1 and 15 of 33 (45%) patients of group 2 had a complete remission (CR) (P = .2). Eight of 11 (73%) cytogenetically normal patients achieved CR: 5 of 6 (83%) in group 1, and 3 of 5 (60%) in group 2. Five of 12 (42%) cytogenetically abnormal patients achieved CR. No difference in duration of survival (group 1, median = 4.6 months vs. group 2, median = 10.2 months; P = .93) was observed between the 2 groups. We conclude that AML-M6 is typified by multilineage involvement of hematopoietic cells. The morphology of erythroblasts in patients with AML-M6 may correlate with cytogenetic abnormalities and rate of CR.

Autologous or allogeneic bone marrow transplantation compared with intensive chemotherapy in acute myelogenous leukemia. European Organization for Research and Treatment of Cancer (EORTC) and the Gruppo Italiano Malattie Ematologiche Maligne dell'Adulto (GIMEMA) Leukemia Cooperative Groups

BACKGROUND

Allogeneic or autologous bone marrow transplantation and intensive consolidation chemotherapy are used to treat acute myelogenous leukemia in a first complete remission.

METHODS

After induction treatment with daunorubicin and cytarabine, patients who had a complete remission received a first course of intensive consolidation chemotherapy, combining intermediate-dose cytarabine and amsacrine. Patients with an HLA-identical sibling were assigned to undergo allogeneic bone marrow transplantation; the others were randomly assigned to undergo autologous bone marrow transplantation (with unpurged bone marrow) or a second course of intensive chemotherapy, combining high-dose cytarabine and daunorubicin. Comparisons were made on the basis of the intention to treat.

RESULTS

A total of 623 patients had a complete remission; 168 were assigned to undergo allogeneic bone marrow transplantation, and 254 were randomly assigned to one of the other two groups. Of these patients, 343 completed the treatment assignment: 144 in the allogeneic-transplantation group, 95 in the autologous-transplantation group, and 104 in the intensive-chemotherapy group. The relapse rate was highest in the intensive-chemotherapy group and lowest in the allogeneic-transplantation group, whereas the mortality rate was highest after allogeneic transplantation and lowest after intensive chemotherapy. The projected rate of disease-free survival at four years was 55 percent for allogeneic transplantation, 48 percent for autologous transplantation, and 30 percent for intensive chemotherapy. However, the overall survival after complete remission was similar in the three groups, since more patients who relapsed after a second course of intensive chemotherapy had a response to subsequent autologous bone marrow transplantation. Other differences were also observed, especially with regard to hematopoietic recovery (it occurred later after autologous transplantation) and the duration of hospitalization (it was longer with bone marrow transplantation).

CONCLUSIONS

Autologous as well as allogeneic bone marrow transplantation results in better disease-free survival than intensive consolidation chemotherapy with high-dose cytarabine and daunorubicin. Transplantation soon after a relapse or during a second complete remission might also be appropriate.

Rationale for high-dose chemotherapy and application of haematopoietic growth factors in acute myeloid leukaemia

High-dose chemotherapy in acute myeloid leukaemia (AML) is more effective and not associated with a higher risk of lethal complications during the induction phase as compared with less intensive regimens. This seemingly paradoxical finding is explained by the more rapid reduction of the leukaemic cell mass and the faster restoration of normal haematopoesis. In the most recent study on double induction therapy by the German AML Cooperative Group involving 665 adult patients with AML the rate of complete remission was 66%-73%. Haematopoietic growth factors used as part of the anti-tumour regimen offer a number of advantages. These include acceleration of haematopoietic recovery and the potential to enhance the sensitivity of leukaemic blasts when given prior to and during cytostatic therapy. New perspectives to further enhance the intensity of antileukaemic therapy may emerge from the introduction of peripheral stem cell transplantation into the treatment strategy.