High-dose cytarabine and daunorubicin as consolidation therapy for acute myeloid leukemia in first remission: long-term follow-up and results

Survival in 86 patients, aged 15-60, with primary acute myelogenous leukemia, treated with a common program in the Norwegian health regions I, III, IV and V in the period 1990-1995

Eighty-six patients between 15 and 60 yr with primary acute myelogenous leukemia in health regions I, III, IV and V in Norway were treated according to a common protocol from 21 January 1990 until 1 September 1995 (until 1 January 1993 for health region IV). Seventy-one percent of the patients reached complete remission (CR) and went on to receive consolidation treatment. In addition to chemotherapy, 18 patients under the age of 52, i.e. 28% of all patients in this age group, received allogeneic bone marrow transplantation. A follow-up analysis was performed by 1 September 1996. The median overall survival was 15 months, estimated 3-yr survival 30% and estimated survival at 5 yr was 26%. The median duration of 1st CR was 19 months, and the leukemia-free survival at 3 yr was 29%. At follow-up 26/86 patients were alive, 18 in 1st CR (4 after BMT) and 8 in 2nd CR (5 after BMT in 2nd, 1 after BMT in early 1st relapse). These results are comparable to many previously published studies, but may be inferior to the results obtained with more intensive consolidation treatment, including high dose Ara C.

Post-remission therapy of adult acute myeloid leukaemia: one cycle of high-dose versus standard-dose cytarabine. Leukaemia Project Group of the Swiss Group for Clinical Cancer Research (SAKK)

BACKGROUND

Intensification of post-remission therapy improves the cure rate of acute myeloid leukemia (AML) but is often accompanied by unacceptable toxicity. From 1985 to 1992 the Swiss Group for Clinical Cancer Research (SAKK) performed a randomized phase III trial to evaluate the effectiveness of one single postremission course of high-dose cytarabine (HDAC) in terms of leukaemia-free and overall survival in adults with de novo AML.

PATIENTS AND METHODS

Adult (15-65 years) AML patients in remission after two induction courses were randomly assigned to one consolidation course either with standard (SDAC: 100 mg/sqm 24 hours infusion over seven days) or with high-dose cytarabine (HDAC: 3000 mg/sqm every 12 hours as one-hour-infusion for six days). In addition, both arms included daunorubicin (45 mg/sqm daily on days 1 to 3). Thereafter, patients were observed without maintenance until relapse.

RESULTS

After two induction courses 208/276 eligible patients achieved remission (CR: 169, 61%, PR: 39, 14%), 41 were resistant (15%) and 20 died early (7%). Seventy-one patients in remission were not randomized. One hundred thirty-seven were randomized in CR/PR (67 SDAC, 70 HDAC). 4/70 patients randomized to HDAC did not receive it. Treatment-related mortality in HDAC was 1.4% (1/66). WHO grade 3-4 toxicities occurred in 14/67 SDAC and in 38/66 HDAC patients (P < 0.0001). The median event free survival was 10.8 (SDAC) vs. 12.2 months (HDAC; P = 0.18). The median overall survival was 24.6 (SDAC) vs. 32.6 months (HDAC; P = 0.07). Although statistically uncertain, HDAC reduced the hazard of progression (hazard ratio: 0.69, P = 0.08) and of death (hazard ratio: 0.70, P = 0.13). For 112 patients stratified as CR the estimated four-year disease-free survival was 25% (+/-6%) with SDAC and 37% (+/-6%) with HDAC (P = 0.09). The overall survival rates at four years were 38% (+7%) and 48% (+7%), respectively (P = 0.10). In multivariate analysis HDAC significantly reduced the hazard of relapse by 39% compared to SDAC (hazard ratio = 0.61, 95% CI: 0.37-0.99; P = 0.049).

CONCLUSIONS

We conclude that early consolidation of adult AML in CR with a single course of HDAC is superior in terms of outcome to one cycle of SDAC. The results of our intensive, single course HDAC group compare favourably with less intensive, repetitive HDAC cycles, suggesting that Ara-C dose intensity may be more important than total dosage. In addition, our treatment strategy is much less toxic and less expensive.

Etoposide and mitoxantrone as a second cycle of consolidation therapy following high dose cytosine arabinoside and daunorubicin in patients with acute non-lymphocytic leukemia in remission: a pilot study

High dose cytosine arabinoside (ARA-C) has produced long term relapse free survival in 26% to 49% of patients when used as consolidation therapy of acute non-lymphocytic leukemia (ANLL) in first remission. However, the optimal consolidation regimen has not been defined. In this pilot study we attempted to confirm and extend our previous studies of high dose consolidation therapy by administering two cycles of consolidation chemotherapy to patients with ANLL in first remission. The first cycle was high dose ARA-C 3 gm/m2 over 1 hour every 12 hours for 12 doses followed by daunorubicin 45 mg/m2/day for three days. The second cycle was etoposide 75 mg/m2/day for 10 days and mitoxantrone 12 mg/m2/day for three days. Twenty-three patients received high dose consolidation chemotherapy, 13 of whom received the proposed two cycles. The major reason for not receiving the planned second consolidation cycle was life threatening toxicity, primarily fungal infection, during the first consolidation cycle. By actuarial estimate, 46% of patients receiving consolidation chemotherapy were projected to be relapse free at 36 months. There were no deaths during consolidation. Survival was not improved in patients receiving etoposide and mitoxantrone as the second cycle of consolidation therapy as compared to patients receiving only one cycle of consolidation therapy.

Curative chemotherapy for acute myeloid leukemia: the development of high-dose ara-C from the laboratory to bedside

In the bench to bedside development of drugs to treat patients with cancer, the common guide to dose and schedule selection is toxicity to normal organs patterned after the preclinical profile of the drug. An understanding of the cellular pharmacology of the drug and specifically the cellular targets linked to the drug's effect is of substantial value in assisting the clinical investigator in selecting the proper dose and schedule of drug administration. The clinical development of ara-C for the treatment of acute myeloid leukemia (AML) provides a useful paradigm for the study of this process. An understanding of the cellular pharmacology, cytokinetics and pharmacokinetics of ara-C in leukemic mice showed substantial schedule-dependency. Exposure to high doses for a short duration (C x t) resulted in a palliative therapeutic outcome. In marked contrast, exposure to lower doses for a protracted period (c x T) was curative. Clinical use of ara-C in patients with AML patterned after the murine experience, c x T approach, has been of limited benefit in terms of long-term disease-free survival. Studies with human leukemia blasts from patients have shown that for the majority of patients, the initial rate-limiting step is membrane transport, the characteristics of which are substantially affected by extracellular drug concentration (dose). This pharmacologic impediment is eliminated with the blood levels attained during the infusion of gram doses (1-3 gm/m2) of the drug (high-dose ara-C, HiDaC) for shorter periods of time, a C x t approach. Clinical confirmation of these pharmacologic observations is evident in the therapeutic efficacy of HiDaC in patients with relapsed or SDaC-refractory acute leukemia. This is further emphasized by the significantly improved leukemia-free survival of patients with AML treated with HiDaC intensification during remission compared to those patients treated with milligram doses typical of SDaC protocols. Thus, the identification and monitoring of important parameters of drug action in tumors during the course of a clinical trial can be of substantial assistance in optimizing drug dose and schedule so as to attain the best therapeutic index.

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.

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.

Bone marrow transplantation vs. high-dose cytorabine-based consolidation chemotherapy for acute myelogenous leukemia. A long-term follow-up study of quality-of-life measures of survivors

Thirty patients previously treated for acute leukemia were studied on the average of 5-6.5 years postdiagnosis in regard to issues of quality of life. Of these 30, 11 were treated with bone marrow transplantation, 19 were treated with conventional chemotherapy. Overall, significant differences were not found between the two groups in regard to evidence of depression symptoms, multifocal psychiatric symptomatology, or on any subscale of a test evaluating problems and rehabilitation needs of cancer patients. A step-wise regression was done, controlling for baseline covariates that included type of medical treatment, months since diagnosis, type of induction chemotherapy protocol, sex of patient, and age of patient. Significant differences in quality of life were not found between the treatment groups.

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.

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.

rHuGM-CSF after high-dose chemotherapy in post-remission acute leukemia

Post-remission high-dose chemotherapy has been an important advance in the treatment of adult acute leukemia (AAL). Without the use of colony-stimulating factors (CSFs) in this program, the mortality rate varies from 5 to 17%, and infectious complications arise in more than 50%. These findings limit the widespread use of such forms of therapy. The use of high-dose ara-C (HIDAC) alone or in combination with other drugs is the most common regimen studied, however neither other drug combinations nor the addition of supporting CSFs have been extensively explored. For this reason we studied the effect of high-dose cyclosphosphamide-etoposide (CECY) plus recombinant human granulocyte-macrophage (rHuGM)-CSF with the intention of decreasing morbimortality and prolonging disease-free survival (DFS). Since 1992 we have included 51 complete remission patients with AAL in the CECY plus rHuGM-CSF protocol. The maximal myelosuppression occurred in a mean of 6.4 days, and the mean days required for absolute neutrophil count recovery was 13 days and for platelets 21 days (p < 0.0001). No toxic deaths occurred and only two serious infectious complications were seen. After two years of follow-up, 50% of de novo acute myelogenous leukemia patients had relapsed at 13 months, and 50% of de novo adult acute lymphocytic leukemia patients had relapsed at 15 months. In a recent update, we have not seen a significant difference when compared to historic groups. The CECY protocol does not appear to be superior in prolonging DFS compared to HIDAC as a post-remission strategy for newly diagnosed AAL. The main difference was the absence of toxic deaths and minimal serious infectious complications in the CECY protocol. Therefore, we suggest that the use of rHuGM-CSF in post-remission programs should be included in future studies.

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.

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

BACKGROUND

About 65 percent of previously untreated adults with primary acute myeloid leukemia (AML) enter complete remission when treated with cytarabine and an anthracycline. However, such responses are rarely durable when conventional postremission therapy is administered. Uncontrolled trials have suggested that intensive postremission therapy may prolong these complete remissions.

METHODS

We treated 1088 adults with newly diagnosed AML with three days of daunorubicin and seven days of cytarabine and randomly assigned patients who had a complete remission to receive four courses of cytarabine at one of three doses: 100 mg per square meter of body-surface area per day for five days by continuous infusion, 400 mg per square meter per day for five days by continuous infusion, or 3 g per square meter in a 3-hour infusion every 12 hours (twice daily) on days 1, 3, and 5. All patients then received four courses of monthly maintenance treatment.

RESULTS

Of the 693 patients who had a complete remission, 596 were randomly assigned to receive postremission cytarabine. After a median follow-up of 52 months, the disease-free survival rates in the three treatment groups were significantly different (P = 0.003). Relative to the 100-mg group, the hazard ratios were 0.67 for the 3-g group (95 percent confidence interval, 0.53 to 0.86) and 0.75 for the 400-mg group (95 percent confidence interval, 0.60 to 0.94). The probability of remaining in continuous complete remission after four years for patients 60 years of age or younger was 24 percent in the 100-mg group, 29 percent in the 400-mg group, and 44 percent in the 3-g group (P = 0.002). In contrast, for patients older than 60, the probability of remaining disease-free after four years was 16 percent or less in each of the three postremission cytarabine groups.

CONCLUSIONS

These data support the concept of a dose-response effect for cytarabine in patients with AML who are 60 years of age or younger. The results with the high-dose schedule in this age group are comparable to those reported in similar patients who have undergone allogeneic bone marrow transplantation during a first remission.

Benefit of high-dose cytarabine-based consolidation chemotherapy for adults with acute myelogenous leukemia

Despite consolidation and/or maintenance chemotherapy most patients with newly diagnosed acute myelogenous leukemia relapse such that only 20-30% survive free of recurrence at five years. To evaluate the long-term effects of dose-intensive consolidation, we analysed 123 consecutive patients, age 16 to 84 (median 48 years), who received high-dose cytarabine-based consolidation chemotherapy. After a median follow-up of 88 months (range 26 to 126 months), 38 patients remain alive, with 26 in continued remission from 45 to 126+ months. Median remission duration for all eligible patients is 14 months (range 1.3 to 126 months) and actuarial leukemia-free survival at five years is 24 +/- 8%. Median survival from remission is 24 months (range 1.3 to 126 months) and actuarial survival from remission is 31 +/- 9%. Eighty-two patients (67%) have relapsed with an actuarial risk of relapse of 71 +/- 9% at five years. Adverse prognostic factors were age over 45 and male gender. When compared to historical controls (P = 0.02), dose-intensive consolidation produced improved leukemia-free survival for patients age < 45, but compliance and enhanced toxicity in the older age groups may limit further dose intensification.

Treatment of advanced acute leukaemia with allogeneic bone marrow transplantation from unrelated donors

Bone marrow transplantation from a histocompatible sibling donor may produce complete remission in patients with induction failure or relapsed acute leukaemia. Through the National Marrow Donor Program, histocompatible bone marrow from unrelated donors has become available for high-risk patients. In this study we analyse the results of matched unrelated bone marrow transplant in 55 patients with highly advanced acute myelogenous and acute lymphoblastic leukaemia. 28 patients with advanced acute lymphoblastic leukaemia and 27 patients with advanced acute myelogenous leukaemia, age 2-51, were treated with high-dose chemoradiotherapy and transplantation of 6/6 HLA matched (n = 46) or one antigen mismatched (n = 9) unrelated donor bone marrow. After a median follow-up of 36 months, 13 patients remain alive 17-74 months after transplant for a 2-year actuarial disease-free and overall survival of 23 +/- 12% (median disease-free survival 3.5 months). The actuarial risk of relapse is 24 +/- 16% at 1 year. Moderate to severe graft-versus-host disease occurred in 27/47 evaluable patients (57%). Significant prognostic factors for poor leukaemia-free survival include age > 21, abnormal karyotype, and active leukaemia at the time of transplant. Other pretreatment characteristics such as gender or type of leukaemia were not significant prognostic factors. Our results show that matched unrelated bone marrow transplant for patients with advanced acute leukaemia may provide long-term leukaemia-free survival, but transplant-related complications produce a significant impact on survival with older age and adverse disease characteristics predicting for poor prognosis.

Long-term outcome of postremission chemotherapy for adults with acute myeloid leukemia using different dose-intensities

The long-term results of postremission chemotherapy for 122 consecutive, unselected adults (15-65 years) with acute myeloid leukemia (AML) were assessed in two sequential prospective studies involving an identical 3/7-type induction regimen, and in those achieving remission, another course for early consolidation using 1 day of daunorubicin instead of three. Forty-one patients reaching C.R. during the first study period, were treated with an intensive ablative maintenance ("IM") program for a period of 9 months. They were randomized to either 6 cycles of induction-type regimen or to 6 cycles of an alternating-type regimen consisting of high-dose (HD)-Ara C/AMSA or 5-azacytidine/AMSA every 6 weeks. There was no difference in disease-free survival (DFS) or survival. Results are compared with 27 patients reaching C.R. on the subsequent protocol where IM was replaced by intensive, short-term consolidation ("IC") using 1 cycle of intermediate-dose Ara C plus AMSA and 1 cycle of HD-AraC/AMSA. Fifteen patients received both courses of IC as scheduled, 12 refused the second cycle. There was no significant difference in DFS or survival. Seventeen out of the 122 patients refused either IM or IC following early consolidation ("refusals"). They received no further treatment and served as control. Fourteen percent of all patients underwent autologous or allogeneic bone marrow transplantation (BMT) at different stages of their disease, equally distributed amongst the IM and IC-group. Median DFS was 3.3 months in the refusal group, 12.4 months in the IM-group, and 18.4 months in the IC-group when censored for BMT (p = 0.01) with 6%, 12%, and 40% in C.C.R. at 50 months. Accordingly, median survival was 5.4, 20 and 47 months (p = 0.001) with 6%, 15%, and 45% of patients alive at 5 years. There was a definite trend (p = 0.14) for a higher proportion of long-term survivors in the IM-group when BMT was performed (not censored), while long-term survival was identical in the IC-group whether BMT was considered for analyses (not censored) or not (censored). Median follow-up for both studies is 5.6 years, the longest, 10 years. In conclusion, progressive increments in the intensity of postremission therapy yields in a graded, significant improvement of remission duration and survival.

Acute myeloid leukemia in Manitoba. The consequences of standard "7 + 3" remission-induction therapy followed by high dose cytarabine postremission consolidation for myelosuppression, infectious morbidity, and outcome

BACKGROUND

To the authors' knowledge, the natural history of myelosuppression and infectious complications associated with the use of standard cytarabine (ARA-C) plus daunorubicin ("7 + 3") remission-induction therapy for adult acute myeloid leukemia (AML) and high dose ARA-C (HDARA-C) consolidation has not been described completely.

METHODS

A retrospective study of untreated adult AML patients receiving standard 7 + 3 induction followed by "5 + 2" and HDARA-C consolidation was undertaken to describe the relationship of the myelosuppression profiles, blood product use, and infectious morbidity, and to correlate this finding with the outcome of antileukemic therapy. Multivariate techniques were used to evaluate variables of prognostic importance.

RESULTS

Fifty-nine percent of the patients achieved remission after a median of 35 days; almost half (48%) of these patients required more than one 7 + 3 induction course. For one, two, and three induction courses, the mean number of days the patients experienced severe neutropenia (< 0.5 x 10(9)/l) were 22.5 +/- 10.9, 39.3 +/- 14.3, and 47.4 +/- 9.7 days (P < 0.001), respectively, and the infection rates were 1.45, 2.45, and 3 infections per course (P < 0.0001), respectively. The pattern of blood product use was similar. HDARA-C consolidation was the most significant factor related to prolonged disease free survival, however the myelosuppression profiles and infection rates were surprisingly similar to those for the single 7 + 3 induction courses.

CONCLUSIONS

The 7 + 3 induction regimen used in this center provided only limited antileukemic activity, while requiring multiple induction courses in a high proportion of patients. The use of multiple induction courses had consequences of prolonged myelosuppression, increased blood product use, and incremental risks of infectious complications. HDARA-C consolidation for those who experienced complete remission appeared to improve disease free survival with myelosuppression comparable with that of patients who received primary induction therapy. The infection risk was acceptable, with only a marginal increase in bacteremic and fungal infections.

Plasma and leukemic cell pharmacokinetics of high-dose N4-behenoyl-1-beta-D-arabinofuranosylcytosine in acute leukemia patients

The pharmacokinetics of N4-behenoyl-1-beta-D-arabinofuranosylcytosine (BHAC), a lipophilic antitumor analog of 1-beta-D-arabinofuranosylcytosine (ara-C), was investigated, by assay of plasma and leukemic cells of ten acute leukemic patients receiving 60-minute intravenous (IV) infusion of 700 mg/m2 BHAC, for BHAC and 1-beta-D-arabinofuranosylcytosine 5'-triphosphate (ara-CTP) by high-performance liquid chromatography, ara-C by radioimmunoassay, and 1-beta-D-arabinofuranosyluracil (ara-U) by gas chromatography-mass fragmentography. The plasma concentration of BHAC reached a maximum (173.4 +/- 75.3 micrograms/mL) at the end of the infusion and then declined in a biphasic pattern with an initial-phase half-life (t1/2 alpha) of 1.00 +/- .36 hours and a second-phase half-life (t1/2 beta) of 4.28 +/- 2.35 hours. That of ara-C similarly reached a maximum (102.2 +/- 39.9 mg/mL) at the end of the infusion and then declined with t1/2 alpha of 1.37 +/- 1.11 hours and t1/2 beta of 11.2 +/- 4.31 hours. Intracellular ara-CTP concentration increased in a linear-accumulation manner for the first 4 hours after the infusion, reached a maximum of .081 +/- .112 micrograms/10(7) cells at approximately 7 hours, and then declined very slowly in accordance with a one-compartment model with t1/2 of 13.56 +/- 9.62 hours.

Mitoxantrone and 5-azacytidine for refractory/relapsed ANLL or CML in blast crisis: a leukemia intergroup study

In an effort to determine if cell cycle active agents are augmented when given after non-cell cycle active agents, 104 patients with either multiply relapsed or refractory acute nonlymphocytic leukemia or blast crisis of chronic myelogenous leukemia were treated with mitoxantrone. Patients whose bone marrow did not show significant cytoreduction received 5-azacytidine. Twenty-seven of the 93 evaluable patients (23%) with ANLL achieved a complete remission. A total of 28% of patients receiving mitoxantrone alone achieved remission compared to 15% for those receiving mitoxantrone and 5-azacytidine. Relapsed patients had a higher CR rate (36%) than refractory patients (15%). Nausea, vomiting, and stomatitis were common but rarely severe. The median duration of remission was 3.7 months and patients with abnormal karyotypes had longer remission durations than those with normal karyotypes. In this patient population, there was no evidence that 5-azacytidine given after mitoxantrone increased the complete remission rate.

Long-term outcome of patients with acute myelogenous leukemia: the role of maintenance therapy, consolidation therapy and the predictive value of two in vitro assays

Three successive strategies used to treat acute myelogenous leukemia (AML) patients who entered complete remission are compared with respect to their long term efficacy (> 5 years). Additionally, the ability of two in vitro assays to identify patients who would be long term remitters was assessed. With respect to the proportion of patients in long term remission, 5 years of maintenance therapy, intensive consolidation therapy plus 3 years of additional therapy, and 4 courses of consolidation therapy produced equivalent results with 18 to 22% of patients in remission at 7 years. Patients whose leukemia cells retained high levels of cytosine arabinoside triphosphate (araCTP) and who received maintenance therapy were less likely to experience early relapse than comparably treated patients whose leukemia cells failed to retain araCTP. The failure of leukemia cells to clone in vitro was also associated with a lower early relapse rate for patients who received maintenance therapy. Neither the ability of leukemia cells to retain araCTP nor their ability to clone in vitro were of prognostic significance for patients treated with 4 courses of intensive consolidation therapy.

Induction therapy for acute myelogenous leukemia in patients over 60 years with intermediate-dose cytosine arabinoside, mitoxantrone and etoposide

Twenty-three patients greater than age 60 years with acute myelogenous leukemia (AML) received induction therapy with continuous infusion cytosine arabinoside (1.5 g/m2/day, day 1-3), mitoxantrone (10 mg/m2/day, day 1-3) and etoposide (800 mg/m2, day 4). Patients entering complete remission (CR) were eligible to receive an identical consolidation cycle. Eighteen of the 23 patients (78%; 95% confidence interval 56% to 93%) entered CR. Twelve of these received consolidation therapy and 4 of these remain in remission at 3 to 20 months. Hematologic toxicity of the regimen was acceptable; only 1 patient died following therapy (having attained a CR). Non-hematologic toxicity was mostly mild (grade 2 or less) with one episode of grade 3 cerebellar toxicity. While this regimen induces a high CR rate in patients > age 60 years, relapses remain common and overall survival is too early to assess.

1-Beta-arabinofuranosylcytosine in therapy of leukemia: preclinical and clinical overview

Although the mechanisms of therapeutic efficacy of cytosine arabinoside (Ara-C) are multifactorial, the pharmacodynamic basis for its cytotoxicity and therapeutic efficacy lies in its intracellular metabolism and the retention of the active metabolite, Ara-C triphosphate (Ara-CTP), which is a competitive inhibitor of DNA polymerase. Additional determinants of tumor cell sensitivity include Ara-CMP incorporation into cellular DNA, the size of the competing normal metabolite, deoxycytidine/5'-triphosphate pool, and the heterogeneity in growth kinetics of tumor cells, S-phase vs cells in other phases of the cell cycle. With high-dose Ara-C, substantial amounts of Ara-CTP are formed in phases of the cell cycle. The presence of high intracellular concentration with prolonged retention of Ara-CTP could lead to the inhibition of cell growth of the cells entering S-phase as a consequence of inhibition of DNA-polymerase and/or incorporation into cellular DNA, resulting in a chain termination. Pharmacokinetically, Ara-C is rapidly eliminated from plasma. In mice, pharmacokinetic parameters of Ara-C are not sufficient predictors for the observed differences in their in vivo antitumor activity. Although these mice were bearing different tumor types (L1210 Ara-C sensitive or P-388 relatively more resistant), the observed differences in tumor response were achieved under identical plasma Ara-C concentrations and area under the concentration time curve. The observed antitumor activity in L1210 cells is primarily associated with higher Ara-CTP pools and retention (T1/2 > 4 hr) in tumor cells as compared with normal bone marrow cells. In the least responsive tumor (P-388), although Ara-CTP pools were sufficiently high, retention of the drug in tumor cells and in normal cells is poor with a T1/2 < 2 hr. Thus, unlike mice bearing leukemia L1210 cells, alteration of the mode and dose of administration of Ara-C in mice bearing P-388 could only result in increased host toxicity with no therapeutic gain. Similarly in patients with acute nonlymphocyte leukemia (ANLL), there is no significant correlation between plasma Ara-C concentration and the intracellular concentrations or retentions of Ara-CTP. In some patients the highest Ara-CTP pools in leukemic myeloblast cells are achieved at a lower level of plasma Ara-C and decrease further with the increase of plasma Ara-C. Thus, in the in vivo model system and in ANLL patients with no prior chemotherapy, Ara-CTP retention is a critical factor associated with response to this agent, in particular its direct association with duration of complete response.(ABSTRACT TRUNCATED AT 400 WORDS)

Intensive sequential post-induction therapy for adults with acute myelogenous leukemia in first remission: long-term follow-up and results

We designed a post-induction therapy including intensive sequential therapy with non-cross-resistant drugs in an effort to prolong disease-free survival (DFS) for adults with acute myelogenous leukemia. Forty-five patients entered this study and 33 of 35 patients entering complete remission received the post-induction therapy. With a median follow-up for survivors of 3.5 years from complete remission, the actuarial 5-year DFS was 46% +/- 19% (95% confidence interval). The five-year DFS for patients over 45 years of age was comparable to that for patients under 45 years of age (50% +/- 26% vs 47% +/- 28%). Furthermore, the actuarial 5-year DFS for patients who required two courses of induction therapy was comparable to that for patients who required only one course of induction therapy (45% +/- 29% vs 50% +/- 25%). The toxicity of post-induction therapy was tolerable and no patients died during complete remission.

High-dose cytosine arabinoside intensification for acute nonlymphocytic leukemia in patients over 56 years of age

One hundred and nine consecutive patients with de novo acute nonlymphocytic leukemia aged over 56 years were admitted with the intention of administering high-dose cytosine arabinoside (HD Ara-C) intensification. After remission induction, the patients were consolidated with a course of daunorubicin (30 mg/m2/day, days 1-3) and Ara-C (100 mg/m2/day, days 1-7), followed by the intensification (Ara-C, 2 g/m2/12 h, days 1-4). The planned induction course was not started in 13 patients because of cardiac failure or unsatisfactory general status. Remission was achieved in 55% (53/96) of the patients. Twenty-seven patients (28%) had refractory disease, seven died early during induction therapy, five died of hemorrhage and three of infection during the hypoplasia that followed induction treatment. Thirty-nine patients started consolidation and 32 had the planned intensification. In these last patients the 3-year leukemia-free survival (LFS) probability was 29% (SE, 8%). No patient died as a consequence of intensification. The relapse rate of the intensified patients did not differ from the relapse rate of those patients who did not receive the planned intensification (p = 0.12). The only pretreatment variables significantly associated with a better LFS were younger age (p = 0.02) and a low WBC at diagnosis (p = 0.04). For the whole patient group, the 3-year survival probability was 15% (SE, 4%). This study shows that elderly patients can tolerate HD Ara-C. The patients completing consolidation-intensification have a currently acceptable LFS. To what extent HD Ara-C contributed to the length of the remissions remains unclear.

A randomized study of the efficacy of postconsolidation therapy in adult acute nonlymphocytic leukemia: a report of the Italian Cooperative Group GIMEMA

The Italian Co-operative Group GIMEMA conducted a randomized trial in adult acute nonlymphocytic leukemia (ANLL) to assess the role of postconsolidation treatment. Of 448 evaluable patients entered into the study, 305 (68%) achieved a complete remission after a standard induction with daunorubicin and cytosine arabinoside (3 + 7; 2 + 5). Those in remission after a consolidation therapy including 4 courses of daunorubicin, cytosine arabinoside, and 6-thioguanine (DAT) were allocated to one of three arms: no treatment, conventional maintenance, or intensive postconsolidation therapy. The median disease-free survival (DFS) was 13 months, and the median survival was 14 months, with 26% surviving at 6.5 years. There was no difference in survival and in disease-free survival among the three postconsolidation arms. In conclusion our study, as others, suggests that the critical period of ANLL treatment is within the first 5-6 months.

Therapy of acute myelogenous leukemia

Treatment of acute myelogenous leukemia (AML) is divided into remission induction and post-remission therapy. Remission induction is usually with cytarabine and an anthracycline. Daunorubicin is commonly used but recent data suggest idarubicin or mitoxantrone are equally effective, possibly better. High-dose cytarabine has also been used for remission induction but is not proven superior. Post-remission treatment is typically with two or more courses of drugs similar to those used for remission induction. Other studies use non-cross resistant drugs and/or high-dose cytarabine. Although some data favor use of high-dose cytarabine, no approach is clearly superior. There is considerable controversy whether persons in first remission and with an HLA-identical sibling should receive a bone marrow transplant immediately or after relapse. Although transplant results appear superior, especially in persons less than 20 years of age, the most effective strategy may be reserving transplants for persons failing chemotherapy. This strategy also applies to persons receiving autologous transplants or transplants from alternative donors, like HLA-matched related or unrelated persons.

Mayo Clinic experience with allogeneic and syngeneic bone marrow transplantation, 1982 through 1990

Between April 1982 and July 1990, 101 patients underwent allogeneic or syngeneic bone marrow transplantation at the Mayo Clinic. This patient population consisted of 30 with acute nonlymphocytic leukemia, 25 with acute lymphoblastic leukemia, 29 with chronic granulocytic leukemia, and 17 with other diseases (aplastic anemia in 7, myelodysplastic syndrome in 5, and lymphoma in 5). The results achieved in our patients who underwent transplantation in first complete remission of both acute nonlymphocytic leukemia and acute lymphoblastic leukemia compare favorably with previously reported results. Only 1 of 15 patients (7%) with acute nonlymphocytic leukemia and 2 of 8 patients (25%) with acute lymphoblastic leukemia who underwent transplantation in first complete remission had a relapse. Thus, we recommend early bone marrow transplantation during initial complete remission for patients with either of these disorders who have adverse prognostic factors. In contrast, of 12 patients with either acute nonlymphocytic leukemia or acute lymphoblastic leukemia who underwent transplantation during relapse, 11 died within 6 months. Therefore, such patients should be offered new experimental treatments. Our patients with chronic granulocytic leukemia fared better when they underwent transplantation early during the course of their disease rather than during the accelerated or blast phase. Prospective studies are needed to determine the best approach in these patients.

Use of high-dose cytarabine in autologous bone marrow transplantation in acute myeloid leukemia

Autologous bone marrow transplantation is widely used as late intensification therapy for patients with AML in remission without an HLA identical donor or who are older than 40-45 years. We report our experience in 21 AML patients in 1st or 2nd CR transplanted with a regimen including HD-ARA-C in addition to Cyclophosphamide (CY) and TBI. The median age was 32 years (3-50). Fourteen patients were transplanted in 1st CR and 7 in 2nd CR. In all but one patient BM harvesting and ABMT were done in the same remission status and after at least 3 courses of consolidation therapy. Two patients (9.5%) died from treatment related toxicity on Day +15 and Day +31. The median time to reach 1000 WBC and 50,000 platelets per cmm was 23 (13-55) and 55 (22-790) days respectively. Only 4 (21%) of the 19 evaluable patients (median observation time of 32 months) relapsed, at 3, 8, 18 and 26 months from ABMT. The projected event free survival curve shows survival of 67% at 96 months with a relapse rate of 26%.

Treatment of resistant acute myeloid leukemia

Although combination cytotoxic chemotherapy induces complete remission in 60-80% of adults with previously untreated acute myeloid leukemia, most patients will ultimately relapse and die from leukemia. Strategies which have been developed for patients with relapsed leukemia include the use of active non-cross-resistant chemotherapeutic agents, allogeneic or autologous bone marrow transplantation, or combined sequential therapy with hematopoietic growth factors and chemotherapy. Most salvage chemotherapeutic regimens use high-dose cytarabine; other agents which have activity include idarubicin, mitoxantrone, etoposide, and high-dose cyclophosphamide. Bone marrow transplantation represents the preferred approach for patients with resistant leukemia offering a likelihood of prolonged disease-free survival. Unique combinations of high-dose chemotherapy and growth factors may provide an alternative therapeutic role in the treatment of resistant leukemia.

Enhancement of anti-neoplastic activity of cytosine arabinoside against human HL-60 myeloid leukemic cells by 3-deazauridine

Drug resistance is one of the major reasons for failure of chemotherapy of acute leukemia with cytosine arabinoside (ARA-C). In order to overcome this problem we have investigated the interaction of ARA-C with 3-deazauridine (3-DU) against HL-60 myeloid leukemic cells. 3-DU is an interesting agent to use in combination with ARA-C, since drug-resistant cells that are deficient in deoxycytidine kinase are very sensitive to this uridine analogue. We have observed that for both short and long drug exposure there was a potent synergistic interaction between ARA-C and 3-DU with respect to their cytotoxic effects on HL-60 leukemic cells. This synergy could be explained by an increased cellular uptake of ARA-C to ARA-CTP by the leukemic cells in the presence of 3-DU, due to the reduction in the pool of dCTP produced by this latter analogue. Since dCTP is a potent feedback inhibitor of the phosphorylation of ARA-C by deoxycytidine kinase, the reduction in the dCTP produced by 3-DU results in an increased rate of phosphorylation of the arabinosyl analogue. Our results suggest that ARA-C and 3-DU may be an interesting drug combination to circumvent drug resistance in the chemotherapy of acute leukemia.

Acute myeloid leukemia in the elderly: biological features and search for adequate treatment

AML in elderly patients is a heterogeneous disease which is characterized by a number of unfavorable features such as development, cytogenetics, blast cell differentiation, and poor treatment response. Specifically, the association between a higher incidence of unfavorable cytogenetic abnormalities in elderly patients and poor prognosis has been well documented. Low treatment response may be due to the specific biology of AML in this patient group, but also to host-specific factors such as higher treatment-related morbidity and mortality. Treatment tolerance cannot be judged on grounds of chronological age alone; risk factor analysis with regard to performance status, organ function, and underlying systemic disease need to be considered as well. For effective induction treatment in elderly patients, instant and intensive chemotherapy appears to be necessary, while delayed treatment or administration of supportive care alone provide unsatisfactory results. Standard-dose ara-C/anthracycline-containing regimens are the treatment of choice in patients with good performance status. However, patients with a WHO grading of greater than 3 might rather benefit from reduced regimens such as low-dose ara-C. At present, greatest improvement of AML treatment in elderly patients can be expected from an improvement of supportive care.

Terminal transferase expression in acute myeloid leukaemia: biology and prognosis

Clinical and biological features were assessed in 114 consecutive previously untreated adult acute myeloid leukaemia (AML) patients whose diagnosis was based on FAB criteria and detailed immunophenotyping. All patients received standard intensive chemotherapy. The main purpose of this study was to establish the prognostic value, if any, of terminal transferase (TdT) expression in myeloid leukaemia. TdT positive cells (7-80% of total blast cells) were detected in 40% of the cases. Among clinical characteristics, a low lactate dehydrogenase (LDH) (less than 250 I.U.) (P = 0.003), a low initial white blood cell count (less than 10 x 10(9)/l) (P = 0.002), and an absolute neutrophil count (less than 5 x 10(9)/l) (P = 0.02) were associated with TdT-positivity. FAB classification was not predictive of TdT expression, and there was no difference in the distribution of FAB subtypes between the groups. Multivariate analysis combining clinical and laboratory data indicated that a low expression of the monocytic antigen CD14 was predictive of TdT positivity in AML (P = 0.01). Karyotyping showed no difference in the pattern of occurrence of specific abnormalities between the TdT+ and the TdT- group. When clinical and immunophenotype data were included in a prognostic model, the patient's age was highly predictive of response (P less than 0.001), and only the CDw65 antigen contributed to the response model (P = 0.07). TdT+ patients with a low expression of CD11b achieved a higher frequency of response at a borderline level of significance (P = 0.06). Frequency of response to chemotherapy, the response duration or overall survival were not influenced by TdT expression.

Long-term outcome of adults with acute myelogenous leukaemia: results of a prospective, randomized study of chemotherapy with a minimal follow-up of 7 years

In a prospective study running between 1981 and 1983, a group of 156 adult (under 60 years of age) patients with de-novo acute myelogenous leukaemia were randomly assigned to receive a daunorubicin, cytosine arabinoside and thioguanine combination or a regimen containing lower dosages of these drugs but also containing etoposide and vindesine. Patients who entered complete remission received maintenance therapy for 2 years. The survival and remission duration curves of the two groups were exactly superimposable and for this long-term analysis all patients have been considered together. The follow-up times range between 84 and 104 months. Actual survival at 7 years is 15% (95% confidence intervals 9-20%), with a stable curve thereafter. Actual probability of continuous complete remission at 7 years is 22% (95% C.I. 13-31%) with a stable curve beyond that point. These findings, similar to those of the few other studies of chemotherapy with comparable follow-up times, suggest that only a small fraction of adult patients become long-term survivors, irrespective of the precise type or amount of antineoplastic agents administered.

Cytosine arabinoside in the treatment of acute myeloid leukemia: the role and place of high-dose regimens

Cytosine arabinoside (AraC) is one of the most active drugs in the treatment of acute leukemias and is widely applied at all phases of therapy. In spite of extensive clinical and experimental investigations, its intracellular metabolism and especially its mechanism of action are still not fully elucidated. Controversy also continues about the most appropriate way and dose of administration; which differs by more than 100 fold in clinical studies ranging from low-dose, over standard and intermediate dose regimens, to high-dose protocols. The present review is focused on the role and place of high-dose AraC treatment in acute myeloid leukemia (AML). Based on available clinical and experimental data, the following conclusions can be drawn: Not considering possible but not yet demonstrated beneficial long-term effects, the incorporation of high-dose AraC into induction therapy has not resulted in an improvement of overall remission rate, with the possible exception of patients with slow initial cytoreduction after a first course of conventional treatment. Promising results, however, emerge from high-dose AraC-based consolidation protocols, which need confirmation in prospectively randomized comparative trials. In relapsed and refractory AML, higher than conventional doses undoubtedly enhance the efficacy of AraC salvage therapy. The question of whether the antileukemic activity of intermediate-dose regimens with 500-1,000 mg/m2 AraC is equivalent to that of high-dose protocols applying 2,000-3,000 mg/m2 AraC, however, remains open but may soon be answered by ongoing controlled clinical and pharmacologic investigations.

Bone marrow transplantation or chemotherapy as post-remission treatment of adult acute myelogenous leukemia

We compared three consolidation regimens in patients with acute myelogenous leukemia in first remission. Thirty-four patients received only intensive consolidation chemotherapy (SIC); 28 patients were scheduled to undergo an autologous bone marrow transplant (auto-BMT) and 44 patients an allogeneic BMT (allo-BMT). Twenty-seven of them were referred in first remission for allo-BMT. Nineteen patients achieved a complete remission after salvage treatment. All other patients obtained a remission after one or two courses of a standard combination of cytosine arabinoside and daunorubicin. Except for the patients who were referred in remission, all patients received intermediate dose cytosine arabinoside and amsacrine as a first consolidation treatment. The median ages of the three groups were 48 (SIC), 39 (auto-BMT) and 33 years (allo-BMT). Two patients relapsed before auto-BMT and 1 before allo-BMT. The median interval from the date of complete remission to the auto- or allo-BMT was 3 months. In total, 80% of the patients of the SIC group relapsed, compared to 50% of the patients belonging to the auto-BMT group and 35% of the 44 patients who were scheduled to receive an allo-BMT. The overall median disease-free survival was 14 months, 30% of the patients being alive and disease-free at 3 years. The disease-free survival rate at three years was 25% for the SIC group, 30% for the allo-BMT group and 40% for the ABMT group (P = 0.45). Our study shows no benefit for bone marrow transplantation over intensive consolidation treatment. However, large randomized trials are required to define the real value of these treatment modalities.

Short-term remission induction and consolidation therapy for adult acute myelogenous leukemia

One hundred and ninety two adults (median age 44 years) with de novo or secondary (n = 17) acute myelogenous leukemia (AML) were managed with a maximum of six intended courses with adriamycin 25 mg/m2/d for three days, plus cytarabine 200 mg/m2/d and 6-thioguanine 200 mg/m2/d for seven days (short-term therapy, STT). Twenty eight patients not in remission after the first course were given cytarabine 2 g/m2/bd for six days, a treatment that was highly toxic and gave a low CR rate. One hundred and twenty-six patients overall (66 per cent) achieved a complete remission (CR), 117/164 (71 per cent) after one to three standard courses (median 1), and 9/28 (32 per cent) after high-dose cytarabine. Median CR duration was 12 months. By multivariate analysis, younger age, blast count less than or equal to 50 x 10(9)/L, and de novo AML were associated with a better outcome (p less than 0.05). CR duration correlated favourably with FAB M3 morphology and total number (five or six) of cycles (p less than 0.05). In patients receiving five or six total courses, median CR length resulted 15.5 months and leukemia-free survival at 3 years 37 per cent. Therapy was curtailed in one fourth of CR patients because of unacceptable toxicity, and there were nine early deaths attributable to therapy-related complications among 126 CR cases. STT may be a worthwhile form of treatment for patients with de novo non-hyperleukocytic AML that are able to tolerate five or six consecutive induction-like chemotherapy courses.

Treatment strategies in acute myeloid leukemia (AML). A. First-line chemotherapy

Chemotherapy remains the backbone of treatment in AML. Of all adult patients 65% go into remission and have a chance of longer survival and of even being cured. Among the responders, 25% can be cured by intensive and long-term chemotherapy. Since the effect of chemotherapy appears not to be limited to a special period of time, its antileukemic and curative potential could be further exploited by multiple-step chemotherapy combining double induction, intensified consolidation and long-term maintenance. Improved antimicrobial treatment and the use of hematopoietic growth factors may help making multiple-step chemotherapy practicable, thereby increasing the cure rate in AML.

Therapy of acute myelogenous leukemia in patients over the age of 50: a randomized Southeastern Cancer Study Group trial

In a randomized trial, 299 evaluable patients with acute myelogenous leukemia, age greater than or equal to 51, were initially randomized to cytosine arabinoside, 100 mg/m2/day, by continuous intravenous infusion for seven days, plus either daunorubicin 45 mg/m2/day x 3 (DA), or m-AMSA 200 mg/m2/day x 3 days (MA). Complete remission (CR) rates were not significantly different, 47% for DA and 42% for MA. Toxicities were similar except that severe hepatic toxicity, serum bilirubin greater than or equal to 7 mg/dl, was more frequent in patients receiving MA (10%) than in patients receiving DA (4%), p less than 0.05. Deaths during induction were significantly more frequent in patients receiving MA (38%) than in patients receiving DA (25%), p = 0.018. Patients achieving a CR received thioguanine, cytosine arabinoside, and daunorubicin (TAD) for three cycles as consolidation. Among evaluable patients, 82/102 (80%) stayed in CR during these three cycles. Patients were then randomized to either no maintenance or to DA every 13 weeks x 4 cycles, at a dose slightly lower than used for induction. Remission duration was similar for the two maintenance programs, 10.7 months for no maintenance and 8.5 months for DA. The percentage of patients evaluable for maintenance achieving three year relapse-free survival was similar for the two maintenance programs, 28% for no maintenance and 21% for DA. However, overall survival was significantly greater (40 vs 12 months, p = 0.007) for patients receiving no maintenance therapy, due to greater survival after recurrence in these patients. At each phase of the study there were substantial numbers of non-evaluable cases, often due to incomplete evaluation of remission status. Of the 379 patients initially entered into the trial, 35% obtained a complete remission. Of all the patients who achieved a complete remission, 61% were both evaluable and in remission upon completion of the maintenance phase. Of these patients who completed the maintenance phase in remission, 15% were relapse free survivors three years following initiation of maintenance therapy. Overall, only 3.2% of patients who entered the trial (35% x 61% x 15%) were continuous relapse-free survivors three years into the maintenance phase.

Comparison of antineoplastic activity of cytosine arabinoside and 5-aza-2'-deoxycytidine against human leukemic cells of different phenotype

A comparison of the cellular and molecular pharmacology of the deoxycytidine analogues cytosine arabinoside (Ara-C) and 5-aza-2'-deoxycytidine (5-AZA-CdR) on human myeloid (HL-60), T-cell (Molt-3) and B-cell (RPMI-8392) leukemic cell lines was investigated. Ara-C was a more potent inhibitor of growth than 5-AZA-CdR. In a colony assay, 5-AZA-CdR was a more potent cytotoxic agent than Ara-C for both the myeloid and B-cell leukemic cells, but not for the T-cell leukemic cells. The total cellular uptake of 5-AZA-CdR was greater than Ara-C for the myeloid and B-cell leukemic cells, whereas for the T-cells the uptake of the arabinosyl analogue was greater. Ara-C produced a potent inhibition of DNA synthesis, whereas no inhibition was detected with 5-AZA-CdR during a short incubation. In contrast, 5-AZA-CdR produced a potent inhibition of DNA methylation whereas Ara-C produced a slight increase in the methylation of DNA. This study shows that there are significant differences in the antineoplastic activity of Ara-C and 5-AZA-CdR against human leukemic cell lines of different phenotype and that these differences are related to differences in the metabolism of these two deoxycytidine analogues and to their effects on DNA synthesis and methylation.