Long-term outcome after intensive therapy with etoposide, melphalan, total body irradiation and autotransplant for acute myeloid leukemia

Autologous Hematopoietic Stem Cell Transplantation in Acute Myelogenous Leukemia

The clinical outcomes of autologous hematopoietic stem cell transplantation (ASCT) in acute myelogenous leukemia (AML) have improved over time. Indeed, numerous studies have demonstrated that ASCT is associated with a lower relapse rate and acceptable nonrelapse mortality compared with chemotherapy alone in patients with AML. In addition, ASCT is also associated with comparable overall survival outcomes to those of allogeneic hematopoietic stem cell transplantation in some patients with AML. To date, age, cytogenetic and molecular risk stratification, and minimal residual disease (MRD) status have been shown to be closely related to clinical outcomes following ASCT. ASCT is recommended for patients with favorable-risk and intermediate-risk AML in first complete remission and patients with acute promyelocytic leukemia in second complete remission for whom a matched sibling donor is not available. MRD status pre-ASCT is the most important factor to consider when determining whether a patient is eligible for ASCT and can effectively predict clinical outcomes after ASCT. Advanced age is not an absolute contradiction for ASCT. In this review, we describe the literature and clinical trials evaluating the outcomes of ASCT in patients with AML and discuss the indications for ASCT therapy. Because the greatest concern in ASCT recipients is early relapse, important factors that should be monitored before ASCT and future perspectives in this area are also presented.

A phase I study of targeted, dose-escalated intravenous busulfan in combination with etoposide as myeloablative therapy for autologous stem cell transplantation in acute myeloid leukemia

BACKGROUND

Busulfan and etoposide have been used as myeloablative therapy for autologous hematopoietic stem cell transplantation (HSCT) in adults with acute myeloid leukemia (AML) for > 20 years. The use of targeted intravenous (I.V.) busulfan has significantly improved the tolerability and efficacy of this regimen. We designed a dose-escalation study to examine the maximum tolerated dose (MTD) of targeted I.V. busulfan with bolus etoposide as preparative therapy for autologous HSCT in AML.

PATIENTS AND METHODS

In this single-center, phase I study, adult AML patients received I.V. busulfan targeted to either an area under the curve (AUC) of 1250 (cohort 1) or 1400 (cohort 2) μmol/min over 16 doses. Dose adjustments based on plasma pharmacokinetics occurred before doses 2 and 11. Etoposide 60 mg/kg I.V. was administered 24 hours after the last busulfan dose and 3 days before stem cell infusion.

RESULTS

Twelve patients with intermediate-risk AML in first complete remission were treated. All patients in cohort 1 and 5 patients (83%) in cohort 2 were within 10% of the target AUC. The MTD was not reached, although Grade ≥ 3 mucositis occurred in 3 patients (50%) in cohort 1 and in 4 patients (66%) in cohort 2, limiting further dose escalation. Two-year relapse-free survival was 33% in cohort 1 versus 67% in cohort 2 (P = .08).

CONCLUSION

Etoposide and targeted, dose-escalated I.V. busulfan as myeloablative therapy for autologous HSCT in AML is safe, with mucositis being the most significant toxicity. A phase II study is warranted to further evaluate the activity and safety of busulfan targeted to AUC 1400 μmol/min.

High-dose idarubicin plus busulfan as conditioning regimen to autologous stem cell transplantation: promising post-remission therapy for acute myeloid leukemia in first complete remission?

The optimal post-remission therapy (PRT) for acute myeloid leukemia (AML) remains uncertain. We reported 32 AML patients in first complete remission (CR1) undergoing autologous hematopoietic stem cell transplantation (ASCT) with a characteristic conditioning regimen, termed I-Bu, based on high-dose idarubicin plus busulfan, which considerably strengthened antileukemic activity. Most patients were in better or intermediate-risk group except that cytogenetic or molecular risk information was missing for 18.7 % of the patients. Unpurged peripheral blood stem cells were used in all the cases. The adverse effects were mild and reversible. Only one case of transplant-related mortality was observed. All the patients in this study acquired hematopoietic reconstitution after ASCT. After a median follow-up of 30 (6-119) months, 24 patients (75.0 %) were alive in which 20 (62.5 %) patients were in continuous CR. There were 11 (34.4 %) patients who relapsed after HSCT. Cumulative relapse probability was about 40 % after 24 months. Median OS and DFS have not been reached. Patients in the better and intermediate-risk group had different clinical outcomes, but the differences were not statistically significant. ASCT with I-Bu regimen is possibly promising PRT for better and intermediate-risk AML patients in CR1.

In haematopoietic SCT for acute leukemia TBI impacts on relapse but not survival: results of a multicentre observational study

The aim of this study was to determine whether parameters related to TBI impacted upon OS and relapse in patients with acute leukemia in CR who underwent haematopoietic SCT (HSCT) in 11 Italian Radiation Oncology Centres. Data were analysed from 507 patients (313 males; 194 females; median age 15 years; 318 with ALL; 188 with AML; 1 case not recorded). Besides 128 autologous transplants, donors included 192 matched siblings, 74 mismatched family members and 113 unrelated individuals. Autologous and allogeneic transplants were analysed separately. Median follow-up was 40.1 months. TBI schedules and HSCT type were closely related. Uni- and multi-variate analyses showed no parameter was significant for OS or relapse in autologous transplantation. Multivariate analysis showed type of transplant and disease impacted significantly on OS in allogeneic transplantation. Disease, GVHD and TBI dose were risk factors for relapse. This analysis illustrates that Italian Transplant Centre use of TBI is in line with international practice. Most Centres adopted a hyperfractionated schedule that is used worldwide (12 Gy in six fractions over 3 days), which appears to have become standard. TBI doses impacted significantly upon relapse rates.

Autologous blood cell transplantation versus HLA-identical sibling transplantation for acute myeloid leukemia in first complete remission: a registry study from the Center for International Blood and Marrow Transplantation Research

The optimal post-remission treatment for acute myeloid leukemia in first complete remission remains uncertain. Previous comparisons of autologous versus allogeneic hematopoietic cell transplantation noted higher relapse, but lower treatment-related mortality though using bone marrow grafts, with treatment-related mortality of 12-20%. Recognizing lower treatment-related mortality using autologous peripheral blood grafts, in an analysis of registry data from the Center for International Blood and Transplant Research, we compared treatment-related mortality, relapse, leukemia-free survival, and overall survival for patients with acute myeloid leukemia in first complete remission (median ages 36-44, range 19-60) receiving myeloablative HLA-matched sibling donor grafts (bone marrow, n=475 or peripheral blood, n=428) versus autologous peripheral blood (n=230). The 5-year cumulative incidence of treatment-related mortality was 19% (95% confidence interval, 16-23%), 20% (17-24%) and 8% (5-12%) for allogeneic bone marrow, allogeneic peripheral blood and autologous peripheral blood stem cell transplant recipients, respectively. The corresponding figures for 5-year cumulative incidence of relapse were 20% (17-24%), 26% (21-30%) and 45% (38-52%), respectively. At 5 years, leukemia-free survival and overall survival rates were similar: allogeneic bone marrow 61% (56-65%) and 64% (59-68%); allogeneic peripheral blood 54% (49-59%) and 59% (54-64%); autologous peripheral blood 47% (40-54%) and 54% (47-60%); P=0.13 and P=0.19, respectively. In multivariate analysis the incidence of treatment-related mortality was lower after autologous peripheral blood transplantation than after allogeneic bone marrow/peripheral blood transplants [relative risk 0.37 (0.20-0.69); P=0.001], but treatment failure (death or relapse) after autologous peripheral blood was significantly more likely [relative risk 1.32 (1.06-1.64); P=0.011]. The 5-year overall survival, however, was similar in patients who received autologous peripheral blood (n=230) [relative risk 1.23 (0.98-1.55); P=0.071] or allogeneic bone marrow/peripheral blood (n=903). In the absence of an HLA-matched sibling donor, autologous peripheral blood may provide acceptable alternative post-remission therapy for patients with acute myeloid leukemia in first complete remission.

Relative survival of long-term hematopoietic cell transplant recipients approaches general population rates

Whether the annual mortality rates of long-term hematopoietic cell transplant (HCT) survivors ever return to that of the general population is unclear. This study sought to determine the annual long-term mortality rates of allogeneic and autologous HCT recipients who had survived 5 years or more disease-free posttransplant and calculate their relative survival rates. Patients were included if they had a first allogeneic or syngeneic HCT for acute leukemia, chronic myelogenous leukemia (CML) or myelodysplastic syndromes (MDS), or autologous HCT for acute myelogenous leukemia (AML) or lymphoma in Australia or New Zealand between 1992 and 2001, recorded on the Australasian Bone Marrow Transplant Recipient Registry (ABMTRR) database, and were known to have survived, disease free, 5 years or more posttransplant. The annual mortality rates of 5-year transplant survivors were compared to standard Australian and New Zealand populations using relative survival. A total of 1461 HCT survivors (688 postallograft, 773 postautograft) were included in this study. The 10-year survival probability for 5-year allograft survivors was slightly higher than that of 5-year autologous survivors (93.4% versus 89.6%, P=.06). The relative survival of both allogeneic and autologous 5-year survivors was never <97% of that of the general population. However, it was statistically significantly lower than expected in the sixth to ninth years posttransplant, with no obvious pattern of either improvement or deterioration from 6 to 10 years posttransplant. This study indicates that annual relative survival rates of long-term survivors of allogeneic HCT performed in Australia and New Zealand for acute lymophoblastic leukemkia (ALL), AML, CML, and MDS are slightly, but significantly lower than population rates in the 6th to 10th years posttransplant. Annual relative survival rates of long-term survivors of autologous HCT performed in Australia and New Zealand for AML and lymphomas are also slightly lower than population rates up to the 10th year posttransplant. Late deaths from transplant and disease-related causes are unusual, but continue to occur for many years post-HCT.

Auto-SCT for AML in second remission: CALGB study 9620

We studied the feasibility and efficacy of a two-step approach to Auto-SCT for patients with AML in second remission. Step 1 consisted of consolidation chemotherapy using cytarabine 2000 mg/m(2) i.v. every 12 h for 4 days plus etoposide 40 mg/kg total dose by continuous i.v. infusion over the same 4 days. PBSC were collected after G-CSF stimulation during recovery from this chemotherapy. Step 2, auto-SCT, used a preparative regimen of oral BU 16 mg/kg over 4 days followed by etoposide 60 mg/kg i.v. Of the 50 patients entered on Step 1, two died from treatment complications, and seven failed to proceed to transplantation. A median CD34+ cell dose of 5.9 x 10(6)/kg was collected in a median of three collections. With a median follow-up of 8.2 years, 5-year disease-free survival (DFS) is 28%. The most important prognostic factor was cytogenetics, with acute promyelocytic leukemia (APL) patients having a 5-year DFS of 67% compared with 16% for others. We conclude that this two-step approach to autologous transplantation produces good CD34+ mobilization and that this approach has cured some patients. Results in patients with APL are especially promising.

The role of cytotoxic therapy with hematopoietic stem cell transplantation in the therapy of acute myelogenous leukemia in adults: an evidence-based review

Clinical research examining the role of hematopoietic stem cell transplantation (HSCT) in the therapy of acute myelogenous leukemia (AML) in adults is presented and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the treatment recommendations. Treatment recommendations based on the evidence are presented in Table 3, entitled Summary of Treatment Recommendations Made by the Expert Panel for Adult Acute Myelogenous Leukemia, and were reached unanimously by a panel of AML experts. The identified priority areas of needed future research in adult AML include: (1) What is the role of HSCT in treating patients with specific molecular markers (eg, FLT3, NPM1, CEBPA, BAALC, MLL, NRAS, etc.) especially in patients with normal cytogenetics? (2) What is the benefit of using HSCT to treat different cytogenetic subgroups? (3) What is the impact on survival outcomes of reduced intensity or nonmyeloablative versus conventional conditioning in older (>60 years) and intermediate (40-60 years) aged adults? (4) What is the impact on survival outcomes of unrelated donor HSCT vesus chemotherapy in younger (<40 years) adults with high risk disease?

Predictors of response to reinduction chemotherapy for patients with acute myeloid leukemia who do not achieve complete remission with frontline induction chemotherapy

Eighty-one patients with acute myeloid leukemia who had persistent leukemia following standard induction therapy with cytarabine plus daunorubicin (7+3 regimen) underwent reinduction therapy with a combination of mitoxantrone, etoposide, and high-dose cytarabine (HiDAC). Patients achieving complete remission (CR) then received consolidation therapy with HiDAC plus mitoxantrone. Patients with matched sibling donors were referred for allogeneic bone marrow transplantation (BMT) in CR-1. The overall response rate to reinduction was 53%. The major adverse predictors of CR on multivariate analysis were poor risk cytogenetics, a higher % bone marrow blasts prior to reinduction therapy and increased age. The median relapse-free survival (RFS) was 9 months and the estimated 2-year RFS was 30%. No significant predictors of RFS or overall survival (OS) were found among the patients achieving CR. Patients undergoing allogeneic BMT in CR-1 after double induction had a 50% 2-year OS. Patients relapsing after achieving CR with double induction had a poor outcome with a 4% 1-year OS. The results indicate that patients with poor risk cytogenetics or marrow blast percentage >or= 60% following 7+3 induction have a low probability of achieving CR with reinduction and should be considered for novel approaches to improve CR rates. Patients achieving CR are at high risk of relapse and should be considered for allogeneic BMT or novel strategies to attempt to reduce relapse rates.

Feasibility and safety of autotransplants with noncryopreserved marrow or peripheral blood stem cells: a systematic review

The objective of this systematic review is to examine the feasibility and safety of autologous noncryopreserved stem-cell transplants. This technique avoids the cost of establishing and maintaining a cryopreservation facility and may be of value for transplant centers in regions with limited economic resources. The primary outcome was the graft failure rate. In addition, a detailed description of the high-dose therapy regimens employed was undertaken. Secondary outcomes were transplant-related mortality and neutrophil and platelet engraftments times. Sixteen well-conducted nonrandomized studies met the eligibility criteria. Only two cases of graft failure (0.36%) occurred among 560 assessable patients receiving high-dose therapy and autotransplant for non-Hodgkin's lymphoma, Hodgkin's lymphoma, multiple myeloma, germ-cell tumors and acute leukemias. The most traditional high-dose schedules were used, although often modified to shorter regimens. High-dose melphalan appeared especially useful given its short half-life and was used to treat multiple myeloma by most groups. Secondary outcomes were comparable to those reported in the most relevant studies addressing standard (cryopreserved) autotransplant. According to this study, the use of autologous noncryopreserved hematopoietic progenitors to support patients undergoing high-dose therapy is feasible and safe.