Postremission therapy in older patients with de novo acute myeloid leukemia: a randomized trial comparing mitoxantrone and intermediate-dose cytarabine with standard-dose cytarabine

Development of farnesyltransferase inhibitors for clinical cancer therapy: focus on hematologic malignancies

Farnesyltransferase inhibitors (FTIs) target and inhibit the peptide prenylating enzyme farnesyltransferase. This new class of signal transduction inhibitors is being tested clinically in diverse malignancies, with encouraging results in hematololgic malignancies and breast cancer in particuarl. Critical questions have yet to be answered, for example, optimal dose and schedule, disease subgroups most likely to respond, and appropriate combinations with standard cytotoxics and new biologics. Gene profiling studies of malignant target cells obtained during FTI clinical trials will help to identify patients who are likely to respond to FTIs and to develop mechanisms for overcoming FTI resistance. Clinical trials and correlative laboratory studies in progress and under development will define the optimal roles of FTIs in cancer patients.

Treatment of older patients with acute myeloid leukemia

In recent years, major advances have been made in the treatment of acute myeloid leukemia (AML) in younger patients, but the prognosis for elderly AML patients remains poor. This review focuses on current and emerging data on the treatment of AML in the elderly. Most elderly patients are not considered for induction therapy. Cytarabine and anthracycline combination therapies induce remission in up to 50% of cases of newly diagnosed AML, and the median survival duration ranges between 5 and 10 months. Targeted therapies such as monoclonal antibodies (gemtuzumab ozogamicin), farnesyltransferase inhibitors (tipifarnib), tyrosine kinase inhibitors (lestaurtinib) and hypomethylating agents (decitabine and valproic acid) are being investigated in elderly patients with AML. Autologous and reduced-intensity allogeneic stem cell transplantation has been used in selected patients.

The role of post-remission chemotherapy for older patients with acute myelogenous leukemia

Standard practice in older patients with acute myeloid leukemia (AML) is induction chemotherapy (ICT) followed by post-remission chemotherapy (PRT). We previously reported a median disease-free survival (DFS) and overall survival (OS) for patients in complete remission (CR) of 7.5 and 13.5 months, respectively, in 30 older patients treated with standard ICT and PRT (study A). We designed a subsequent trial excluding PRT (study B). Forty patients with AML age > or =60 years were treated with ICT consisting of standard dose cytosine arabinoside and mitoxantrone followed with granulocyte-macrophage colony-stimulating factor subcutaneously starting day 11 if the bone marrow aspirate and biopsy was hypocellular. Median age was 68 years. Myelodysplasia preceded AML in 37% of patients. Favourable, normal, and unfavourable karyotypes were seen in 7.5%, 55%, and 37.5% of patients, respectively. Twenty-one patients (52.5%) achieved CR. Median DFS and OS for patients in CR were 6.2 and 10.8 months, respectively. Study A and B differed by the addition of PRT in study A. However, DFS and OS did not differ significantly between patients treated in study A or study B (P = 0.21 and P = 0.15, respectively). PRT has not clearly improved survival in older patients with AML, and therefore the routine addition of chemotherapy to older patients in complete remission is not indicated.

Sequential response-adapted induction and consolidation regimens idarubicin/cytarabine and mitoxantrone/etoposide in adult acute myelogenous leukemia: 10 year follow-up of a study by the Canadian Leukemia Studies Group

PURPOSE

The Canadian Leukemia Studies Group (CLSG) sought to test the safety and efficacy of response-adapted, non-cross resistant chemotherapy in de novo acute myeloid leukemia (AML). The combinations of idarubicin 12 mg/m(2)/d on days 1 - 3 and Ara-C (200 mg/m(2)/d) on days 1 - 7 (IDAC) followed by mitoxantrone 10 mg/m(2)/day, and etoposide 100 mg/m(2)/day, on days 1 - 5 (NOVE) were used according to patient response to induction and consolidation.

PATIENTS AND METHODS

In this multi-centre open-label phase II study, 140 patients up to age 80 were given induction with IDAC. Patients were entered between March 1993 and August 1995. If patients had persistent blasts at day 14 or on recovery, they were given NOVE. As consolidation, patients achieving complete remission (CR) with IDAC were given 1 further cycle of IDAC and 1 cycle of NOVE. Patients achieving CR after NOVE were given 2 further cycles of NOVE.

RESULTS

76% of all patients achieved remission after IDAC +/- NOVE, 81% in patients aged < or =60 years and 67% in patients aged >60. Overall, induction mortality was 11% and toxicity was similar to other cooperative group studies. Median follow-up was 104.0 months with 95% CI: (100.0, 105.2). Median overall survival (OS) in responding patients < or =60 was not reached: of the 79 responders < or =60, 35 died. The median disease free survival (DFS) in these responding patients was 22.7 (14.9, na) months. Median OS and DFS in responding patients >60 was 10.0 (7.3, 15.2) months and 7.5 (6.2, 15.2) months, respectively.

CONCLUSION

The results of this trial are very encouraging and suggest that there may be long-term benefit to this method. On the basis of these results, a randomized phase III trial has been performed.

Adding low-dose gemtuzumab ozogamicin to fludarabine, Ara-C and idarubicin (MY-FLAI) may improve disease-free and overall survival in elderly patients with non-M3 acute myeloid leukaemia: results of a prospective, pilot, multi-centre trial and comparison with a historical cohort of patients

We report the final results of a prospective multi-centre trial testing the combination of chemotherapy (fludarabine, cytosine arabinoside and idarubicin; FLAI) followed by low-dose gemtuzumab ozogamicin (GO), for induction treatment of patients with CD33+ acute myeloid leukaemia (AML). Forty-six consecutive patients were treated: the median age was 66 (range: 60-80) years; the karyotype was unfavourable in 12 patients (26%), intermediate in 33 (71%) and favourable in one (3%). Eleven major infectious complications were recorded. There was one early death. Of the 45 evaluable patients, 24 achieved a complete response (CR; 52%), 66% and 33% in good-intermediate/poor karyotype patients. Median duration of CR was 7 (3-24) months. The cumulative incidence of relapse was 37% with an actuarial 2-year survival of 54%. These results were compared with 47 patients matched for age and karyotype who received FLAI, without GO. The proportion of patients achieving CR was comparable. However, patients with de novo AML receiving GO (n = 26) had a significantly lower risk of relapse at 2 years when compared with patients not receiving GO (n = 35) (40% vs. 80%, P = 0.01) and significantly better overall 2-year survival (40% vs. 14%P = 0.02). Patients with secondary AML had comparable outcome whether or not they received GO. This GO-based induction chemotherapy has a good toxicity profile. In keeping with a recent prospective randomised trial, the addition of GO seems to prolong disease-free survival.

Impact of socioeconomic status and distance from treatment center on survival in patients receiving remission induction therapy for newly diagnosed acute myeloid leukemia

BACKGROUND

While socioeconomic status (SES) and the distance patients travel to a treatment center (DTC) impact survival of certain solid tumors, little is known of their influence in acute myeloid leukemia (AML).

METHODS

We retrospectively reviewed patients receiving remission induction therapy for AML at the Cleveland Clinic between January 1997 and December 2005. Demographic data were obtained from medical records. Income and DTC were determined using online databases. Known prognostic factors (age, WBC count at diagnosis, cytogenetics, AML etiology) were collected and controlled for in Cox proportional hazards analysis.

RESULTS

Induction chemotherapy was administered to 281 patients; 91% were Caucasian (C), 8% were African American (AA), and 1% were neither (non-AA non-C). The median DTC was 24 miles (range, 0.9-2058), and median annual household income was USD 38,972 (range, USD17,496-143,220). With a median follow up of 22.6 months, the median overall survival (OS) was 11.3 months. In multivariable analyses, age >or=60 years, unfavorable cytogenetics, initial WBC count and secondary AML significantly influenced survival (p<0.001, p<0.001, p=0.035, and p=0.010, respectively). OS was similar for AAs and non-AA non-Cs compared to Cs (HR=1.12, 95% CI=.61-2.07, p=.71, and HR=0.87, CI=0.21-3.62, p=.84, respectively). Neither DTC (HR=1.00, 95%CI=0.98-1.01, p=.96 per 20 mile increment) nor SES (HR=1.02, 95%CI=0.92-1.13, p=.77 per USD10,000 annual income increase) had an impact on OS.

CONCLUSION

Unlike with many solid tumors, SES and DTC are not predictive of outcome in AML patients.

Blood and marrow transplantation in elderly acute myeloid leukaemia patients - older certainly is not better

Acute myeloid leukaemia in the elderly is a disease with distinct biological properties, commonly associated with leukaemic cell treatment resistance and with an increased number of high-risk features, including concomitant myelodysplasia and poor-risk cytogenetic abnormalities such as monosomy 5 and 7. Complete remission rates after standard induction chemotherapy in patients above age 60 years are less than 50%, with long-term survival rates below 10%. Post-remission stem cell transplant therapies have not been studied extensively. Autologous transplants can result in an acceptable 3-year leukaemia-free survival rate of up to 47%, yet this procedure is applicable only to a small minority of patients. Myeloablative allogeneic transplants similarly show feasibility in selected few patients and in general are very toxic. Non-myeloablative allogeneic transplants are associated with reduced toxicity, but are plagued by an increased relapse rate. The latter strategy appears promising, but must be validated in larger, multi-centre prospective trials, in which outcomes are compared to non-transplant approaches.

International Society of Geriatric Oncology Chemotherapy Taskforce: evaluation of chemotherapy in older patients--an analysis of the medical literature

The elderly comprise the majority of patients with cancer and are the recipients of the greatest amount of chemotherapy. Unfortunately, there is a lack of data to make evidence-based decisions with regard to chemotherapy. This is due to the minimal participation of older patients in clinical trials and that trials have not systematically evaluated chemotherapy. This article reviews the available information with regard to chemotherapy and aging provided by a task force of the International Society of Geriatric Oncology (SIOG). Due to the lack of prospective data, the conclusions and recommendations made are a consensus of the participants. Extrapolation of data from younger to older patients is necessary, particularly to those patients older than 80 years, for which data is almost entirely lacking. The classes of drugs reviewed include alkylators, antimetabolites, anthracyclines, taxanes, camptothecins, and epipodophyllotoxins. Clinical trials need to incorporate an analysis of chemotherapy in terms of the pharmacokinetic and pharmacodynamic effects of aging. In addition, data already accumulated need to be reanalyzed by age to aid in the management of the older cancer patient.

Therapeutic strategy of untreated de novo acute myeloid leukemia in the elderly: the efficacy of continuous drip infusion with low dose cytarabine and etoposide

PURPOSE

To evaluate the efficacy and safety of a novel low dose chemotherapy as a remission induction regimen for elderly de novo AML patients ineligible for intensive chemotherapy.

METHOD

Fifty consecutive patients, aged 60 to 85, with untreated de novo AML were enrolled. Patients with poor PS or defined non-hematological complications were given continuous drip infusion of low dose cytarabine (Ara-C), 20 mg/body and etoposide (VP-16), 50 mg/body for 10 days (AV group). Patients without those comorbidities were given intensive induction therapy (S group). After achieving complete remission (CR), S group patients and those with improved PS in AV group received consolidation chemotherapy with intensive regimen (S-S or AV-S group), and other patients received AV regimen repeatedly (AV-AV group).

RESULTS

Eighteen (64%; 95% confidence interval (CI), 0.47-0.82) of 28 patients in AV group and 16 (73%; 95% CI, 0.54-0.91) of 22 patients in S group achieved CR, respectively. The 1-year OS rates of the patients in the AV-AV group (n = 9), AV-S group (n = 9), and S-S group (n = 16) were 22, 81, and 78%, respectively. Although the sample size was small, no significant difference was observed for the 1-year OS rate between the AV-S and S-S groups. Regimen related death were 4 patients in S group, while no patient in AV group.

CONCLUSION

Therapeutic strategy consisting of remission induction using AV regimen and consolidation using intensive regimen after improving PS is beneficial in the management of elderly AML patients who have difficulty in tolerating for intensive induction chemotherapy.

Impact of conditioning regimen intensity on outcome of allogeneic hematopoietic cell transplantation for advanced acute myelogenous leukemia and myelodysplastic syndrome

We reviewed 136 patients with advanced acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) undergoing allogeneic transplantation to assess the impact of conditioning regimen intensity on outcome. Thirty-nine patients receiving nonmyeloablative stem cell transplantation (NST) were compared with 97 patients receiving myeloablative transplantation. Patients receiving NST were at high risk for treatment-related complications given that they were older, 57 vs 43 years (P < .001), and more likely had received previous or myeloablative transplantation (54% vs 2%; P < .0001). The cumulative risk of relapse was higher for patients after NST (61% vs 38%; P = .02). The 100-day mortality was less after NST (15% vs 32%) Overall survival (OS) at 2 years was 28% for NST and 34% for myeloablative transplantation (P = .89). Progression-free survival (PFS) at 2 years was 20% for NST and 31% for myeloablative transplantation (P = .31). Cox regression analysis showed that the intensity of the conditioning regimen had no effect on either OS or PFS. Despite the high-risk features of patients with advanced AML or MDS undergoing NST, OS and PFS in these patients was similar to those in patients receiving myeloablative transplantation. These results demonstrate that dose intensity plays a significant role in control of disease after transplantation, but that this benefit is negated by increasing treatment-related mortality. These results suggest that NST is a reasonable alternative for patients with advanced AML and MDS at high risk for complications after myeloablative transplantation.

Postremission treatment of elderly patients with acute myeloid leukemia in first complete remission after intensive induction chemotherapy: results of the multicenter randomized Acute Leukemia French Association (ALFA) 9803 trial

In elderly patients with acute myeloid leukemia (AML) treated intensively, no best postremission strategy has emerged yet. This clinical trial enrolled 416 patients with AML aged 65 years or older who were considered eligible for standard intensive chemotherapy, with a first randomization comparing idarubicin with daunorubicin for all treatment sequences. After induction, an ambulatory postremission strategy based on 6 consolidation cycles administered monthly in outpatients was randomly compared with an intensive strategy with a single intensive consolidation course similar to induction. Complete remission (CR) rate was 57% with 10% induction deaths, and estimated overall survival was 27% at 2 years and 12% at 4 years, without notable differences between anthracycline arms. Among the 236 patients who reached CR, 164 (69%) were randomized for the postremission comparison. In these patients, the multivariate odds ratio in favor of the ambulatory arm was 1.51 for disease-free survival (P.05) and 1.59 for overall survival from CR (P.04). Despite repeated courses of chemotherapy associated with a longer time under treatment, the ambulatory arm was associated with significantly shorter rehospitalization duration and lower red blood cell unit and platelet transfusion requirements than observed in the intensive arm. In conclusion, more prolonged ambulatory treatment should be preferred to intensive chemotherapy as postremission therapy in elderly patients with AML reaching CR after standard intensive remission induction.

Impact of remission induction chemotherapy on survival in older adults with acute myeloid leukemia

BACKGROUND

Significant controversy surrounds the use of remission induction chemotherapy (IC) in older adults with acute myeloid leukemia (AML). Earlier clinical trials have yielded conflicting results and possibly a minor survival benefit, often offset by a longer hospitalization time.

METHODS

To evaluate the role of IC in patients with AML, a case control study of patients 60 years or older treated at the Cleveland Clinic Taussig Cancer Center between 1997 and 2005 was conducted. Forty-four patients who did not receive IC were matched by a propensity analysis to 138 patients who received an anthracycline-based regimen.

RESULTS

The unadjusted median survival of patients who did not receive IC was 53 days, compared with 197 days (P < .001) for those who did. After further adjusting for age, gender, race, leukocyte count at presentation, AML cytogenetics, history of prior hematologic disorder, and assessing for comorbidities, not receiving IC was still associated with worse survival (hazards ratio of 1.88; 95% confidence interval, 1.15-3.05 [P = .01]). Additional predictors of poor outcomes in older adults with AML included higher leukocyte count at presentation, poor-risk cytogenetics, and African-American race (compared with Caucasians).

CONCLUSIONS

The study suggests improved outcomes in older adults with AML who undergo remission induction therapy.

Prognostic Factors in Elderly Patients with AML and the Implications for Treatment

The outcome of older patients with acute myeloid leukemia (AML) has not improved in the last three decades. These patients are more likely to have comorbid illness, poor performance status, and impaired organ function. These clinical features limit their ability to tolerate intensive cytotoxic chemotherapy and result in greater early mortality. The AML seen in elderly patients is also more likely to have evolved from a prior hematologic disorder, and the leukemic blasts are more likely to have poor-risk structural and numeric cytogenetic abnormalities and expression of multidrug resistance protein (MDR1). These blast features have been associated with greater resistance to therapy. Attempts to improve outcome have generally been unsuccessful. Priming of leukemic blasts with granulocyte colony-stimulating factors during cytarabine therapy, granulocyte colony-stimulating factor support to speed neutrophil recovery following induction therapy, inhibition of the MDR1 p-glycoprotein efflux pump, the use of alternative anthracyclines, and the addition of high-dose cytarabine have all been investigated in the last three decades. Further manipulation of standard cytotoxic chemotherapy alone is unlikely to improve the outcome for the majority of patients with AML. Incorporation of molecularly targeted therapies may prove to be less toxic and/or more efficacious. However, patient selection for clinical trials will continue to confound the interpretation of treatment outcomes on clinical trials of older patients with AML.

A phase 2 study of the farnesyltransferase inhibitor tipifarnib in poor-risk and elderly patients with previously untreated acute myelogenous leukemia

Outcomes for older adults with acute myelogenous leukemia (AML) are poor due to both disease and host-related factors. In this phase 2 study, we tested the oral farnesyltransferase inhibitor tipifarnib in 158 older adults with previously untreated, poor-risk AML. The median age was 74 years, and a majority of patients had antecedent myelodysplastic syndrome. Complete remission (CR) was achieved in 22 patients (14%); partial remission or hematologic improvement occurred in 15 patients, for an overall response rate of 23%. The median duration of CR was 7.3 months and the median survival of complete responders was 18 months. Adverse karyotype, age 75 years or older, and poor performance status correlated negatively with survival. Early death in the absence of progressive disease was rare, and drug-related nonhematologic serious adverse events were observed in 74 patients (47%). Inhibition of farnesylation of the surrogate protein HDJ-2 occurred in the large majority of marrow samples tested. Baseline levels of phosphorylated mitogen-activated protein kinase and AKT did not correlate with clinical response. Tipifarnib is active and well tolerated in older adults with poor-risk AML and may impart a survival advantage in those patients who experience a clinical response.

Outcomes and charges of elderly patients with acute myeloid leukemia

A retrospective database analysis was conducted to evaluate hospitalization outcomes and charges among elderly acute myeloid leukemia (AML) patients. The data source was a longitudinal (2000-2003) inpatient database from 28 US hospitals. Data on 275 AML patients aged 60 and older were analyzed for demographic and treatment characteristics, hospital mortality, length of stay (LOS), overall days of stay (DOS), and charges across multiple admissions. Multivariate modeling was performed to determine factors that influenced outcomes. Overall, 115 (41.8%) patients received inpatient chemotherapy (CT); most (90.4%) received it on the first admission. Of all initial CT regimens 40.9% consisted of a single agent. The mean LOS for initial hospitalization was 23.0 (SD 21.8) days for patients who received CT and 6.7 (SD 7.5) days for those who did not. One quarter (25.3%) of initial hospitalizations resulted in death. On initial hospitalization, mean total charges were $113,118 (SD $220,417) for patients who received CT and $43,999 (SD $190,533) for those who did not; for both groups mean charges were higher than respective subsequent admission charges. Overall, in-hospital mortality did not differ significantly between on-CT and off-CT groups (43.5 and 38.8%, respectively). In multivariate modeling, CT was significantly associated (P < 0.0001) with increased charges and LOS. Elderly patients with AML incurred substantial hospital charges and inpatient mortality. The highest charges and a substantial number of deaths occurred during first admission. Although treatment with CT was associated with increased charges and days in-hospital, inpatient mortality in the two groups was found to be similar.

Fifty Years of Clinical Research by the Leukemia Committee of the Cancer and Leukemia Group B

Progress in the care of patients with leukemia has been one of the great success stories in the field of oncology, and clinical research in leukemia has been the "flagship" of the Cancer and Leukemia Group B since the inception of this organization. Lessons learned from the founders' emphasis on childhood and adult leukemia have been extended broadly over the past 50 years to virtually all types of malignant diseases, and the Leukemia Committee has continued to provide leadership and key contributions. The Leukemia Committee is focused on the individualization of treatment based on distinctive biological and clinical characteristics with the aim of increasing efficacy and decreasing nonspecific toxicity. Our clinical trials in leukemia and myeloma have shifted from primarily empirically derived comparisons of different chemotherapeutic regimens to testing novel concepts such as the role of dose intensity, inhibition of specific mechanisms of drug resistance, the use of hematopoietic growth factors and monoclonal antibodies, and the utility of targeted agents. The Cancer and Leukemia Group B was the pioneer among the cooperative groups in the creation of centralized tissue repositories and the incorporation of correlative laboratory studies as an integral feature of clinical trials, a practice now termed "translational research." Considerable effort has focused on the identification of important pretreatment characteristics, such as morphologic features, immunophenotype, chromosomal abnormalities, and molecular defects, which are significantly associated with outcome in multivariable analyses and which enhance our understanding for the complex biology of these diseases.

Immunologic Approaches to Acute Leukemia in the Elderly

The outcome of older patients with acute leukemia remains poor with few long-term survivors, indicating the need for treatment approaches that target pro-apoptotic pathways not influenced by chemotherapy resistance. For a long time, natural killer (NK) cells have held promise for cancer immunotherapy because, unlike T lymphocytes, they can kill tumor cells without the need for tumor-specific antigen recognition. In the treatment of acute leukemia, NK cell-based therapies have focused on in vivo expansion and activation with cytokines with only modest success. However, recent understanding of the importance of NK receptors for the recognition and lysis of leukemia cells suggests novel therapeutic strategies. The balance of inhibitory and activating signals through surface receptors, recognizing major histocompatibility complex (MHC) class I and class I-like molecules on target cells, determines whether NK cells activate killing. In this review, we discuss the biologic rationale for therapeutic strategies harnessing NK cells and focus on novel directions for their future use in elderly patients with acute leukemia.

Long-term Outcome of Autologous Transplantation of Peripheral Blood Progenitor Cells as Postremission Management of Patients ≥60 Years with Acute Myelogenous Leukemia

The optimal postremission treatment for elderly patients with acute myelogenous leukemia (AML) is presently unknown, but recent studies report the feasibility of autologous stem cell transplantation in this population. To better understand the long-term outcome of autologous transplantation in AML patients > or =60 years of age, we evaluated high-dose chemoradiotherapy preparative conditioning followed by transplantation of peripheral blood progenitor cells procured after a single cycle of cytarabine-based consolidation chemotherapy as postremission therapy in 27 patients aged 60 to 71 years (median age, 65 years) with newly diagnosed AML in first complete remission (CR). The median follow-up from CR for all patients was 13.6 months (range, 6.0-123.1 months). The median follow-up from remission for surviving patients was 81 months (range, 41.4-123.1 months). Seven patients are alive in continuous CR, 19 died from relapse, and 1 died as a result of treatment-related infection. Leukemia-free survival and overall survival are 10.3 and 13.4 months, respectively. Actuarial leukemia-free and overall survival at 3 years are 25% +/- 9% and 28% +/- 9%, respectively. Our results demonstrate that autologous transplantation of peripheral blood progenitor cells is well tolerated and feasible for patients > or =60 years of age with AML in first CR. Future investigation should focus on a randomized study evaluating a larger group of elderly patients in first CR comparing autologous stem cell transplantation with conventional cytarabine-based consolidation chemotherapy to identify the optimal postremission therapy.

Standard induction chemotherapy followed by attenuated consolidation in elderly patients with acute myeloid leukemia

The benefits of intensive post-remission chemotherapy have not been verified in elderly patients with acute myeloid leukemia (AML). To reduce fatal complications caused by intensive post-remission therapy, we performed a prospective phase II multicenter trial of standard induction chemotherapy ('7+3' of cytarabine plus daunorubicin), followed by two cycles of attenuated consolidation therapy ('5+1' of cytarabine plus daunorubicin) for elderly patients with AML, excluding those with M3. Of the 41 patients enrolled in the study, 24 (58.5%) attained CR. Of these 24, 17 (70.8%) completed both planned cycles of consolidation therapy. After a median follow-up of 566 days (range, 63-1190 days) among surviving patients, 15 relapsed, with an actuarial 3-year disease-free survival rate of 22.5%. There were no fatal complications during consolidation therapy. Actuarial 3-year overall survival was 17.0%. These findings suggest that, when compared with previous findings using more intensive consolidation therapy, attenuated consolidation therapy does not compromise outcomes in elderly AML patients.

Fludarabine and cytosine are less effective than standard ADE chemotherapy in high-risk acute myeloid leukemia, and addition of G-CSF and ATRA are not beneficial: results of the MRC AML-HR randomized trial

The optimum chemotherapy schedule for reinduction of patients with high-risk acute myeloid leukemia (relapsed, resistant/refractory, or adverse genetic disease) is uncertain. The MRC AML (Medical Research Council Acute Myeloid Leukemia) Working Group designed a trial comparing fludarabine and high-dose cytosine (FLA) with standard chemotherapy comprising cytosine arabinoside, daunorubicin, and etoposide (ADE). Patients were also randomly assigned to receive filgrastim (G-CSF) from day 0 until neutrophil count was greater than 0.5 x 10(9)/L (or for a maximum of 28 days) and all-trans retinoic acid (ATRA) for 90 days. Between 1998 and 2003, 405 patients were entered: 250 were randomly assigned between FLA and ADE; 356 to G-CSF versus no G-CSF; 362 to ATRA versus no ATRA. The complete remission rate was 61% with 4-year disease-free survival of 29%. There were no significant differences in the CR rate, deaths in CR, relapse rate, or DFS between ADE and FLA, although survival at 4 years was worse with FLA (16% versus 27%, P = .05). Neither the addition of ATRA nor G-CSF demonstrated any differences in the CR rate, relapse rate, DFS, or overall survival between the groups. In conclusion these findings indicate that FLA may be inferior to standard chemotherapy in high-risk AML and that the outcome is not improved with the addition of either G-CSF or ATRA.

Development of the farnesyltransferase inhibitor tipifarnib for therapy of hematologic malignancies

Farnesyltransferase inhibitors (FTIs) represent a new class of signal transduction inhibitors that block the processing of cellular polypeptides that have cysteine terminal residues and, by doing so, interdict multiple pathways involved in proliferation and survival of diverse malignant cell types. Tipifarnib is an orally bioavailable, nonpeptidomimetic methylquinolone FTI that is being tested clinically in diverse hematologic malignancies, in particular myeloid malignancies and myeloma. FTI therapy is accompanied by a relatively low toxicity profile, thereby providing an important alternative to traditional cytotoxic approaches for elderly patients who are not likely to tolerate or even benefit from aggressive chemotherapy. Current laboratory and clinical studies continue to define the determinants of FTI antitumor activity and resistance. The full development of FTIs for the therapy of hematologic malignancies will require the design and testing of rational combinations of cytotoxic, biologic and immunomodulatory agents in the laboratory and the clinic.

Clinical trial of valproic acid and all-trans retinoic acid in patients with poor-risk acute myeloid leukemia

BACKGROUND

Valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, induced in vitro differentiation of primary acute myeloid leukemia (AML) blasts, an effect enhanced by all-trans retinoic acid (ATRA). Clinical responses to VPA were recently observed in patients with myelodysplastic syndrome (MDS). Herein, the authors have described results of a clinical trial with VPA plus ATRA in 26 patients with poor-risk AML.

METHODS

VPA (5-10 mg/kg starting dose) and ATRA (45 mg/m(2)) were administered orally. Low-dose AraC or hydroxyurea were permitted to control leukocytosis. Biologic activity of VPA was confirmed by serial analysis of HDAC2 protein levels in peripheral blood (PB) mononuclear cells.

RESULTS

Nineteen of 26 patients completed at least 4 weeks of VPA/ATRA treatment; 7 patients were withdrawn prematurely because of rapidly progressive disease (n = 3) or unacceptable neurologic and cardiovascular toxicity (n = 4). Additional cytoreductive treatment was required in 58% of patients enrolled. Median treatment duration was 3 months. No patient achieved complete remission, one with de novo AML had a minor response, and two patients with secondary AML arising from myeloproliferative disorder (MPD) achieved a partial remission and clearance of PB blasts, respectively. The latter responses were accompanied by profound granulocytosis and erythrocytosis in both patients, reminiscent of the response pattern known from ATRA treatment of acute promyelocytic leukemia. However, cytogenetic analysis of isolated CD34(+) cells and granulocytes did not reveal terminal differentiation of leukemic blasts.

CONCLUSIONS

Treatment with VPA/ATRA results in transient disease control in a subset of patients with AML that has evolved from a myeloproliferative disorder but not in patients with a primary or MDS-related AML.

Fas, Fas-Associated Death Domain-Like Interleukin 1β -Converting Enzyme-Like Inhibitory Protein, and Apoptotic Features of Elderly Acute Myeloid Leukemia Based on Response to Induction Chemotherapy

A study was performed to examine the clinical outcome of triple-combination induction chemotherapy in 26 elderly Korean acute myeloid leukemia (AML) patients and to investigate apoptotic responses during and after treatment to determine whether the responses can be used as prognostic markers. Patients who had Western blot or polymerase chain reaction analysis findings of higher expression levels of Fas-associated death domain-like interleukin 1beta-converting enzyme-like inhibitory protein (FLIP) on day 7 after chemotherapy were more likely to have complete remission, but there was less or no correlation with Fas or a proapoptosis/apoptosis reaction. Expression of FLIP molecules may be, at least in part, an early prognostic indicator in the treatment of elderly AML patients.

Treatment of older patients with AML

Undertreatment of the older patients with AML can explain, in part, their inferior outcome when compared with that in younger patients. In analogy to the benefit of patients under the age of 60 years from high-dose AraC there are dosage related therapeutic effects in the patients over 60 years in particular for daunorubicin in the induction treatment, and for maintenance versus no maintenance in the post-remission treatment. Utilizing these effects can partly overcome the mostly unfavorable disease biology in older age AML, whereas the role of risk factors involved is not completely understood and the concept of dose-response needs to be requestioned. We recommend an adequate dosage of 60 mg/(m2day) daunorubicin for 3 days in a combination with standard dose AraC and 6-thioguanine given for induction and consolidation and followed by a prolonged monthly maintenance chemotherapy. Further improvements in supportive care may help delivering additional anti-leukemic cytotoxicity. As a novel approach, reduced toxicity preparative regimens may open up allogeneic transplantation for older patients with AML. Other new options like MDR modulators, antibody targeted therapies and tyrosine kinase inhibitors are under clinical investigation. A questionnaire study in patients with AML showed that according to patients' self-assessment intensive and prolonged treatment did not result in decreasing quality of life. This finding did not vary by age under or above 60 years. Given the actual median age in this disease being more than 60 years the adequate management of older age AML remains as the major challenge.

Nonmyeloablative Stem Cell Transplantation for Myelodysplastic Syndrome or Acute Myeloid Leukemia in Patients 60 Years or Older

We analyzed the outcomes of 24 consecutive patients aged >or=60 years with poor-prognosis myelodysplastic syndrome or acute myeloid leukemia undergoing transplantation with nonmyeloablative conditioning using fludarabine (125 mg/m2) and low-dose total body irradiation (2 Gy) followed by allogeneic peripheral blood stem cell grafts from HLA-identical sibling donors. Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and mycophenolate mofetil. The median age of the patients was 64 years (range, 60-71 years). In addition to age, 88% of patients had 1 or more adverse biological features of the disease. With a median follow-up of 21 months, 12 patients are alive, 11 of whom are disease free. The probabilities of 2-year overall and progression-free survival were 52% and 44%, respectively. The cumulative probabilities of relapse and of acute and chronic GVHD were 27%, 45%, and 74%, respectively. Nonrelapse mortality at 100 days and 2 years was 8% and 25%, respectively. Of the 15 patients with extensive chronic GVHD, 1 patient relapsed. These data suggest that nonmyeloablative stem cell transplantation is a feasible treatment option in patients aged >or=60 years with poor-prognosis myelodysplastic syndrome or acute myeloid leukemia. The reasonable disease control with nonmyeloablative transplantation in this high-risk group of patients merits further investigation.

Disease biology rather than age is the most important determinant of survival of patients ≥ 60 years with acute myeloid leukemia treated with uniform intensive therapy

BACKGROUND

The objectives of the current study were to evaluate the outcome of patients > or = 60 years with acute myeloid leukemia (AML) treated uniformly with high-dose daunorubicin containing induction and modified high-dose cytosine arabinoside containing postremission therapy, and to identify factors predictive of complete disease remission (CR) and survival.

METHODS

Between 1998 and 2002, the authors treated 117 newly diagnosed patients (acute promyelocytic leukemia excluded) with AML > or = 60 years (median, 67 years; range, 60-82 years). Karyotype (Medical Research Council classification) at diagnosis was categorized as good risk (n = 3), intermediate risk (n = 69), adverse risk (n = 26), and suboptimal/not done (n = 19). A normal karyotype was seen in 41 patients and 40 (34%) had secondary AML.

RESULTS

The outcome of induction included the following: CR, 62 (53%); early death, 5 (4%); death during hypoplasia, 14 (12%); and resistant disease, 36 (31%). The 3-year event-free (EFS) and overall survival (OS) rates were 9% (95% confidence interval [95% CI], 3-16%) and 17% (95% CI, 9-29%), respectively. In a univariate analysis, cytogenetics, lactate dehydrogenase level, leukocyte count, and performance status were the significant factors for EFS and OS. Age was not a significant prognostic factor for either CR or survival. In a multivariate model, adverse-risk cytogenetics, previous history of myelodysplastic syndrome or antecedent hematologic disorder, and high leukocyte count (> 30 x 10(9)/L) were independent adverse prognostic factors for survival. The impact of adverse karyotype on EFS and OS was time dependent and was observed after 50 and 150 days, respectively.

CONCLUSIONS

The authors concluded that candidacy for intensive therapy in older patients should be based on biologic features of disease and fitness, rather than on age.

A Novel Effective and Safe Consolidation for Patients Over 60 Years with Acute Myeloid Leukemia

PURPOSE

High-dose intermittent cytarabine is an effective postremission treatment for patients with acute myeloid leukemia (AML). This regimen is a safe approach in patients < 60 years but produced severe neurotoxicity in the elderly.

EXPERIMENTAL DESIGN

We have established a dose-reduced age-adapted consolidation using intermediate dose (IDAC; 2 x 1 g/m(2) i.v., days 1, 3, and 5) for AML patients >/= 60 years. Forty-seven de novo AML patients in complete remission (CR; median age, 70 years) were scheduled to receive four consolidation cycles of IDAC.

RESULTS

In 25 of 47 patients (53%), all four cycles were administered: 9 (19%) received three cycles; 7 (15%) received two cycles; and 6 patients (12%) one cycle. Treatment was well tolerated without neurotoxicity. The median number of days with severe neutropenia (absolute neutrophil count < 500/microl) was 9. Neutropenic fever occurred in 22 of 47 patients (49%) during the first cycle, in 24 of 41 (60%) during the second, in 15 of 34 (44%) during the third, and in 18 of 25 (72%) during the fourth cycle. Only 1 patient died during consolidation (cardiac failure). The median overall survival, disease-free survival, and continuous CR were 10.6, 15.5, and 15.9 months, respectively. The probability of overall survival, disease-free survival, and continuous CR at 5 years were 18, 22, and 30%, respectively.

CONCLUSIONS

IDAC is a safe and effective postremission therapy for elderly patients with AML.

In vivo genotoxicity of atrazine to anuran larvae

Atrazine has been an environmental contaminant for more than two decades. While there can be little dispute as to the presence of atrazine in non-target watersheds, the debate has centered on the consequences of this contamination. The purpose of this study was to determine if atrazine is genotoxic to developing anurans. Anurans are one of the groups that have the highest potential for being affected by watershed contamination. In initial studies, larvae from two anuran species were exposed to known genotoxic agents. Upon flow cytometric analysis, those organisms exposed to the genotoxic agents resulted in a statistically significant increase in nuclear heterogeneity. Having demonstrated that flow cytometric analysis could be used to detect genotoxicity in anuran larvae, the larvae of the two species were exposed to different levels of atrazine for various durations. The concentrations and lengths of exposure were consistent (albeit on the higher side) with conditions found in the Midwestern US. In neither species was an increase in nuclear heterogeneity observed. Thus, atrazine at levels and time of exposure representing conditions found contaminating Midwestern watersheds does not appear to be genotoxic to developing anurans.

6-Thioguanine, cytarabine, and daunorubicin (TAD) and high-dose cytarabine and mitoxantrone (HAM) for induction, TAD for consolidation, and either prolonged maintenance by reduced monthly TAD or TAD-HAM-TAD and one course of intensive consolidation by sequential HAM in adult patients at all ages with de novo acute myeloid leukemia (AML): a randomized trial of the German AML Cooperative Group

PURPOSE

To examine the efficacy of prolonged maintenance chemotherapy versus intensified consolidation therapy for patients with acute myeloid leukemia (AML).

MATERIALS AND METHODS

Eight hundred thirty-two patients (median age, 54 years; range, 16 to 82 years) with de novo AML were randomly assigned to receive 6-thioguanine, cytarabine, and daunorubicin (TAD) plus cytarabine and mitoxantrone (HAM; cytarabine 3 g/m2 [age < 60 years] or 1 g/m2 [age > or = 60 years] x 6) induction, TAD consolidation, and monthly modified TAD maintenance for 3 years, or TAD-HAM-TAD and one course of intensive consolidation with sequential HAM (S-HAM) with cytarabine 1 g/m2 (age < 60 years) or 0.5 g/m2 (age > or = 60 years) x 8 instead of maintenance.

RESULTS

A total of 69.2% patients went into complete remission (CR). Median relapse-free survival (RFS) was 19 months for patients on the maintenance arm, with 31.4% of patients relapse-free at 5 years, versus 12 months for patients on the S-HAM arm, with 24.7% of patients relapse-free at 5 years (P =.0118). RFS from maintenance was superior in patients with poor risk by unfavorable karyotype, age > or = 60 years, lactate dehydrogenase level greater than 700 U/L, or day 16 bone marrow blasts greater than 40% (P =.0061) but not in patients with good risk by complete absence of any poor risk factors. Although a survival benefit in the CR patients is not significant (P =.085), more surviving patients in the maintenance than in the S-HAM arm remain in first CR (P =.026).

CONCLUSION

We conclude that TAD-HAM-TAD-maintenance first-line treatment has a higher curative potential than TAD-HAM-TAD-S-HAM and improves prognosis even among patients with poor prognosis.

Decision-making and quality of life in older adults with acute myeloid leukemia or advanced myelodysplastic syndrome

Older patients with acute myeloid leukemia (AML) and advanced myelodysplastic syndrome (aMDS) must decide between receiving intensive induction chemotherapy (IC) or nonintensive chemotherapy/best supportive care (NIC). Little information exists about what factors influence treatment decisions and what quality of life (QOL) is associated with treatment choices. We prospectively examined 43 patients 60 years or older who were interviewed at diagnosis and periodically over 1 year. IC choice was associated with younger age (66 vs 76 years, P=0.01) and AML diagnosis, but not with performance status, comorbidities, or QOL. In total, 63% of all patients reported not being offered other treatment options despite physician documentation of alternatives. Patient and physician estimates of cure differed significantly: 74% of patients estimated their chance of cure to be 50% or greater, yet for 89% of patients physician estimates of cure were 10% or less. IC patients experienced decreased QOL at 2 weeks, but rebounded to baseline and to NIC levels by 6 weeks. Initial QOL is not associated with treatment choice in older AML and aMDS patients. Regardless of treatment choice, patients report not being offered treatment options and overestimate their chances of cure. In IC patients, QOL decreases during hospitalization but rebounds after discharge.

Increased remissions from one course for intermediate-dose cytosine arabinoside and idarubicin in elderly acute myeloid leukaemia when combined with cladribine. A randomized population-based phase II study

Cladribine has single-drug activity in acute myeloid leukaemia (AML), and may enhance the formation of the active metabolite (ara-CTP) of cytosine arabinoside (ara-C). To evaluate the feasibility of adding intermittent cladribine to intermediate-dose ara-C (1 g/m2/2 h) b.i.d. for 4 d with idarubicin (CCI), we performed a 2:1 randomized phase II trial in AML patients aged over 60 years. Primary endpoints were time to recovery from cytopenia and need for supportive care following the first course. Sixty-three patients (median 71 years, range 60-84 years) were included, constituting 72% of all eligible patients. Toxicity was limited, with no differences between the treatment arms. The early toxic death rate was 11%. The median time to recovery from neutropenia and thrombocytopenia was 22 and 17 d from the start of course no. 1, respectively, and the requirement for platelet and red cell transfusions was four and eight units respectively. Patients had a median of 8 d with fever over 38 degrees C, and 17 d with intravenous antibiotic treatment. The overall complete remission (CR) rate was 62%, with 51% CR from one course of CCI in comparison with 35% for the two-drug therapy (P = 0.014). The median survival with a 2-year follow-up was 14 months, and the 2-year survival was over 30%, with no differences between the treatment arms. Considering the median age and our population-based approach, the overall results are encouraging.

Granulocyte-macrophage colony-stimulating factor to increase efficacy of mitoxantrone, etoposide and cytarabine in previously untreated elderly patients with acute myeloid leukaemia: a Swedish multicentre randomized trial

A total of 110 patients, aged 64 years or over, with de novo acute myeloid leukaemia (AML) and white blood cell counts <50 x 109/l were treated with 3 d of cytarabine 1 g/m2 twice daily, mitoxantrone 12 mg/m2 and etoposide 200 mg/m2, randomized with or without the addition of granulocyte-macrophage colony-stimulating factor (GM-CSF) 200 microg/m2. The primary aim was to evaluate the effect of GM-CSF on the remission rate. Secondary aims included comparison of duration of remission, survival and infectious complications and the impact of maintenance therapy with thioguanine. Complete remission (CR) was achieved by 64% of patients without GM-CSF, and by 65% of patients who received GM-CSF, the median remission duration was 13 vs. 6 months, the median overall survival (OS) was 14 vs. 9 months, the mean time to neutrophil recovery was 25 vs. 17 d (P = 0.03) and the number of positive blood cultures was 46 vs. 39 (P = 0.05) respectively. The impact of thioguanine remains unanswered since only 30 patients remained in CR after consolidation therapy. We conclude that induction therapy is feasible with acceptable toxicity in elderly patients with AML, albeit with a high relapse rate and short OS. GM-CSF prior to, and in combination with, induction treatment reduced the time to neutrophil recovery and the number of neutropenic septicaemia cases but did not improve the OS of AML in the elderly.

Farnesyltransferase inhibitors in hematologic malignancies: new horizons in therapy

Farnesyltransferase inhibitors (FTIs) are small-molecule inhibitors that selectively inhibit farnesylation of a number of intracellular substrate proteins such as Ras. Preclinical work has revealed their ability to effectively inhibit tumor growth across a wide range of malignant phenotypes. Many hematologic malignancies appear to be reasonable disease targets, in that they express relevant biologic targets, such as Ras, mitogen-activated protein kinase (MAPK), AKT, and others that may depend on farnesyl protein transferase (FTase) activity to promote proliferation and survival. A host of phase 1 trials have been recently launched to assess the applicability of FTIs in hematologic malignancies, many of which demonstrate effective enzyme target inhibition, low toxicity, and some clinical responses. As a result, phase 2 trials have been initiated in a variety of hematologic malignancies and disease settings to further validate clinical activity and to identify downstream signal transduction targets that may be modified by these agents. It is anticipated that these studies will serve to define the optimal roles of FTIs in patients with hematologic malignancies and provide insight into effective methods by which to combine FTIs with other agents.

Treatment concepts for elderly patients with acute myeloid leukemia

The majority of patients with acute myeloid leukemia (AML) are over 60 years of age at diagnosis. Unlike treatment options for younger adults, those for older patients are limited to non-myeloablative therapy, and many patients are not treatable because of poor performance status. In those who are treatable, long-term survival can be achieved using intensive induction and consolidation chemotherapy. Such curative treatment can be administered in about 70% of elderly patients with AML. In responding patients (up to 60%) the disease-free survival may be almost comparable to that of younger adults. However, treatment-related toxicity results in a higher mortality rate in the elderly patients. Moreover, aggressive chemotherapy cannot be used for 30% of the patients, due to their poor performance status. Currently, palliative cytoreductive treatment and supportive care are considered appropriate for these patients. Recently, however, targeting antileukemic antibodies and inhibitors of signal transduction have been introduced as promising new treatment options. The therapeutic efficiency and toxicity-profiles of these novel drugs are currently under investigation in clinical trials.

Timed sequential therapy of acute myelogenous leukemia in adults: a phase II study of retinoids in combination with the sequential administration of cytosine arabinoside, idarubicin and etoposide

Clinical outcome in acute myeloid leukemia (AML) is unsatisfactory. One strategy to augment cytotoxicity is TST. All-trans retinoic acid (ATRA) down-regulates bcl-2 expression and heightens AML sensitivity to cytosine arabinoside (ara-C)-induced apoptosis in vitro. We designed a trial of ATRA plus ara-C-based TST in an attempt to enhance drug-induced apoptosis and clinical outcome. Between January 1998 and February 2000, 63 patients received induction TST (oral ATRA days 1-6, ara-C and idarubicin days 2-4, VP-16 days 9-11) followed by consolidation TST (ATRA, ara-C and idarubicin followed by a second ara-C infusion days 11-13). Complete remission (CR) was 60%, with higher rates for patients of <60 years (79%), de novo AML (70%), and non-adverse cytogenetics (81%). Median disease-free survival (DFS) for CR patients was 11.2 months (32% at 3+ years). For patients <60 years with de novo AML and non-adverse cytogenetics who underwent two-cycle TST, DFS was 67% at 3+ years. However, patients of age equal to 60 years and those with poor-risk disease features still have poor CR and DFS, despite the addition of ATRA.

The diphtheria toxin/urokinase fusion protein (DTAT) is selectively toxic to CD87 expressing leukemic cells

Diphtheria fusion proteins are a novel class of agents for the treatment of chemotherapy resistant acute myelogenous leukemia (AML). We prepared diphtheria toxin/urokinase fusion protein (DTAT) composed of the amino terminal fragment of the urokinase-type plasminogen activator (uPA) fused to the catalytic and translocation domains of diphtheria toxin (DT) and assessed its activity on leukemic cell lines. The number of uPA receptors (uPAR or CD87) was measured using a phycoerythrin conjugated monoclonal antibody to CD87 and flow cytometry. Seven of 23 cell lines (30%) showed CD87 expression (> or =5000 receptors/cell). DTAT cytotoxicity (IC(50)< or =30pM) was observed in all seven of these samples and none of the 16 samples with low or absent CD87 expression. There was a significant correlation between DTAT sensitivity and CD87 density (P=0.0007). These results show that specific CD87 binding is one factor important in the sensitivity of patient's leukemic blasts to DTAT and demonstrate for the first time that the CD87/uPAR can be used as a target for fusion protein therapy of AML.

Older adults with acute myeloid leukemia

Acute myeloid leukemia (AML) occurs most frequently in older adults, with a median age range from 65 to 70 years. Both the disease and its treatment are distinct from their counterparts in young patients. Herein we characterize the intrinsic biologic features of AML as it occurs in the older population, review currently available therapeutic approaches, and discuss therapeutic strategies in development.

Treatment of acute myeloid leukemia: state-of-the-art and future directions

Despite major recent advances in the understanding of the molecular biology of the disease, the treatment of acute myeloid leukemia (AML) in adults remains challenging. For the 75% of AML patients older than 60 years, currently available treatments produce significant toxicity with poor overall response rates and survival. In younger patients, standard regimens using cytarabine and an anthracycline for induction followed by some form of intensive postremission therapy can produce response rates of 70% with 5-year relapse-free survival rates of 25% to 40%. Chromosomal analyses define three prognostic categories with favorable, intermediate, and unfavorable risk. In older adults, AML appears to be an intrinsically resistant disorder of proximal pluripotent hematopoietic stem cells. A variety of targeted therapies currently in development include modulators of MDR1-mediated drug resistance, immunotherapeutics, angiogenesis inhibitors, proapoptotic antisense oligonucleotides, and specific small molecule inhibitors of tyrosine kinase and farnesyltransferase. For example, oral farnesyltransferase inhibitors have demonstrated activity and tolerability in patients with refractory AML and are now in phase II testing. Such targeted therapeutics offer the promise of novel antileukemic activity combined with an improved therapeutic index.

Acute myeloid leukemia: treatment over 60

Undertreatment of older patients with acute myeloid leukemia (AML) can explain, in part, their inferior outcome when compared to that of younger patients. In agreement with the benefit seen by patients under age 60 from high-dose cytosine arabinoside (Ara-C), there are dose effects in the over 60s, in particular for daunorubicin, in induction treatment and for the duration of postremission treatment. The use of these effects can partly overcome the mostly unfavorable disease biology in older age AML, as expressed by the absence of favorable and the over-representation of adverse chromosomal abnormalities as well as the expression of drug resistance. We recommend an adequate dosage of 60 mg/m2 daunorubicin on 3 days in combination with standard dose Ara-C and 6-thioguanine given for induction and consolidation, and followed by a prolonged monthly maintenance chemotherapy for at least 1 year's duration. Further improvements in supportive care may help to deliver additional antileukemic cytotoxicity. As a novel approach, nonmyeloablative preparative regimens may open up the possibility of allogeneic transplantation for older patients with AML. Other new options like multidrug resistance modulators, antibody targeted therapies and molecular targeting are under clinical investigation. A questionnaire study in patients with AML showed that, according to patients' self-assessment, intensive and prolonged treatment did not result in a diminished quality of life. This finding did not vary by age, under or over 60 years. As the median age in this disease is more than 60 years, the adequate management of AML in older patients remains the major challenge.

The challenge of acute myeloid leukemia in older patients

Acute myeloid leukemia is a disease predominantly affecting older adults, with a median age at diagnosis of 65 years. Compared with younger adults or children with AML, older adults have a poor prognosis and represent a discrete population in terms of disease features, treatment-related complications, and overall outcome. Management of AML in this population often includes intensive, anthracycline-based chemotherapy, which can effect a 1.5- to 4-month survival advantage compared with nonintensive therapy but at a cost of early deaths, long length of hospital stay, and substantial transfusional support. Nonintensive therapy or palliative care remains an important option for many patients. Aggressive postremission therapy or the use of hematopoietic growth factor support does not appear to improve survival. Future directions include therapies targeted at immunomodulation, at angiogenesis, and in particular against intracellular signals that promote proliferation at the expense of differentiation.