Higher incidence of relapse with peripheral blood rather than marrow as a source of stem cells in adults with acute myelocytic leukemia autografted during the first remission

Similar efficacy outcomes with peripheral blood stem cell versus bone marrow for autologous stem cell transplantation in acute myeloid leukemia: Long-term follow-up of the EORTC-GIMEMA randomized AML-10 trial

We report here the long-term follow-up of the only prospective randomized trial of autologous hematopoietic stem cell transplantation (auto-HSCT) with peripheral blood stem cells (APBSCT) versus auto-HSCT with bone marrow (ABMT) in acute myeloid leukemia (AML) patients in first remission (CR). We observed that among patients alive and still in CR 5 years after planned auto-HSCT, approximately 10% of the patients died in the following 10 years. This stresses the need for long-term close surveillance of AML patients after auto-HSCT. Further, long-term follow-up of the trial confirms that APBSCT was comparable to ABMT in term of disease-free-survival and overall survival.

History and Development of Autologous Stem Cell Transplantation for Acute Myeloid Leukemia

This review describes the development of cryopreservation, the birth of autologous stem cell transplantation (ASCT) and its past and present use to consolidate adult patients with acute myelogenous leukemia (AML). It summarizes the first autografts in patients in relapse, the experience of autografting in complete remission (CR), using bone marrow unpurged or purged in vitro with cyclophosphamide-derivatives, and the important shift to peripheral blood stem cells. The review also discusses the results of recent studies in favor of the use of ASCT to consolidate good- and intermediate-risk patients who reach CR with no detectable minimal residual disease, and those which support the inclusion of maintenance therapy post autograft with hypomethylating agents, anti-BCL-2, and, possibly, in the future, anti AML chimeric antigen receptor-T cells. Carefully applied to well-selected patients, ASCT may regain interest, because of its simplicity, its reduced toxicity, lower non-relapse mortality and better quality of life.

Is There Still a Role for Autologous Stem Cell Transplantation for the Treatment of Acute Myeloid Leukemia?

After intensive induction chemotherapy and complete remission achievement, patients with acute myeloid leukemia (AML) are candidates to receive either high-dose cytarabine-based regimens, or autologous (ASCT) or allogeneic (allo-SCT) hematopoietic stem cell transplantations as consolidation treatment. Pretreatment risk classification represents a determinant key of type and intensity of post-remission therapy. Current evidence indicates that allo-SCT represents the treatment of choice for high and intermediate risk patients if clinically eligible, and its use is favored by increasing availability of unrelated or haploidentical donors. On the contrary, the adoption of ASCT is progressively declining, although numerous studies indicate that in favorable risk AML the relapse rate is lower after ASCT than chemotherapy. In addition, the burden of supportive therapy and hospitalization favors ASCT. In this review, we summarize current indications (if any) to ASCT on the basis of molecular genetics at diagnosis and minimal residual disease evaluation after induction/consolidation phase. Finally, we critically discuss the role of ASCT in older patients with AML and acute promyelocytic 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.

Autologous Stem Cell Transplantation Is a Viable Postremission Therapy for Intermediate-Risk Acute Myeloid Leukemia in First Complete Remission in the Absence of a Matched Identical Sibling: A Meta-Analysis

BACKGROUND

The preferred type of postremission therapy (PRT) for intermediate-risk acute myeloid leukemia (AML) in first complete remission (CR1) is a subject of continued debate. Although allogeneic stem cell transplantation (alloSCT) is regarded as a curative strategy for AML, the efficacy of autologous stem cell transplantation (autoSCT) for patients without a matched sibling donor (MSD) has remained controversial.

METHODS

To compare survival outcomes after alloSCT versus autoSCT for patients with intermediate-risk AML in CR1, we performed a meta-analysis of 11 clinical studies. The outcomes included relapse-free survival (RFS), overall survival (OS), relapse rate (RR), and treatment-related mortality (TRM).

RESULTS

Compared with autoSCT, alloSCT showed better RFS, OS, and RR benefits, but higher TRM. Subgroup analysis based on donor category (MSD and matched unrelated donor [MUD]) of alloSCT showed alloSCT from MSD rather than from MUD had better OS benefits compared to autoSCT. For fms-like tyrosine kinase 3 internal tandem duplications (FLT3-ITD) wild-type patients, alloSCT and autoSCT had comparable RFS and OS outcomes.

CONCLUSION

Our results suggest that, in the absence of an available MSD, autoSCT remains a viable PRT alternative for intermediate-risk AML in CR1, especially for FLT3-ITD wild-type patients.

Revisiting autologous transplantation in acute myeloid leukemia

PURPOSE OF REVIEW

Autologous hematopoietic cell transplantation (auto-HCT) has been evaluated as a consolidation treatment for acute myeloid leukemia (AML) in the 1980s and 1990s. These prospective studies from large trials compared auto-HCT with chemotherapy. A comparison was made also with allogeneic hematopoietic cell transplantation (allo-HCT). These studies reported a lower relapse rate with auto-HCT compared with chemotherapy, but without impact on the overall survival. A high transplant-related mortality in that era confounded the relevance of these data.

RECENT FINDINGS

Several prospective studies and a plethora of retrospective registry data have confirmed the potent antileukemic therapy of auto-HCT compared with chemotherapy and, in some instances, have even challenged the presumed superiority of allo-HCT as the definitive therapy for certain patients with AML.

SUMMARY

The aggregate of recent data, prospective and retrospective, strongly suggests an important role for auto-HCT, at least as the most potent nonimmunologic antileukemia therapy. The transplant-related mortality in 2017 is close to that expected from standard consolidation therapy leading to the conclusion that the role of auto-HCT needs to be rigorously revisited, preferably in prospective studies, to establish its precise role in the current era.

Autologous Transplantation for Older Adults with AML

While the majority of patients with acute myeloid leukemia (AML) are above the age of 65 years at diagnosis, the outcome of older AML patients remains disappointing. Even if standard intensive chemotherapy induces morphologic complete remission (CR1), relapses in older AML patients are common leading to poor long-term survival outcomes. Since autologous hematopoietic stem cell transplantation (HCT) offers distinct anti-leukemic effectiveness while avoiding graft-versus-host disease associated with allogeneic transplantation, it represents an option for consolidation treatment in selected older AML patients. However, prospective studies in older AML patients assessing the benefit of autologous HCT compared to chemotherapy consolidation or allogeneic transplantation are lacking. Consequently, clinicians face the dilemma that there is considerable ambiguity on the most appropriate consolidation treatment for older AML patients in CR1. This review highlights the possible role of autologous HCT for consolidation in older AML patients reaching CR1 after induction treatment.

Analyses and treatment of simultaneous bi-lineage malignancies of myeloid leukemia and lymphoma: Two case reports and a literature review

The present study reports two cases of concurrently diagnosed T-lymphoblastic lymphoma (T-LBL) and chronic myeloid leukemia (CML). The literature review revealed that myeloid leukemia may appear secondary to Hodgkin lymphoma or non-Hodgkin lymphoma. However, simultaneous bi-lineage hematologic malignancies are rarely seen and the prognosis is worse than single lineage lymphoma or myeloid leukemia. There were no standard therapies. All simultaneous bi-lineage malignancies of myeloid leukemia and lymphoma reported in Pubmed were combined with the present two cases, to analyses its pathogenesis, features and treatment. It was concluded that the prognosis of bi-lineage hematologic malignancies was poor, however allogeneic hematopoietic stem cell transplantation could improve survival (P=0.033).

Autologous hematopoietic cell transplantation for adult acute myeloid leukemia: An obsolete or resurfacing concept?

Improving long-term outcomes of adult acute myeloid leukemia (AML) patients remains a challenge. Major scientific and clinical advances have led to a better understanding of the disease biology, and the majority of patients achieve a complete remission (CR) after induction therapy. Relapse risk, however, remains considerable and is the leading cause of death in this patient population. Significant efforts to improve outcomes emphasize use of post-remission therapies such as hematopoietic cell transplantation (HCT), an increasingly utilized modality. Improvement in transplantation techniques, understanding of donor:recipient histocompatibility, and increased availability of alternative donors have resulted in greater use of allogeneic HCT. Despite a graft-versus-leukemia effect and lower post-HCT relapse rates, allogeneic HCT continues to be plagued by treatment-related mortality (TRM) and chronic graft-versus-host disease. Better understanding of AML risk stratification and issues relating to minimal residual disease (MRD) as well as extremely low TRM rates with autografts have prompted clinicians to re-explore use of autologous HCT in subsets of favorable and intermediate-risk CR1 AML patients. Herein, we highlight the evolving literature and treatment outcomes for autologous HCT in AML. We provide recommendations for considering this therapeutic modality for treatment intensification in AML.

Long-term follow-up of patients with acute myeloid leukemia surviving and free of disease recurrence for at least 2 years after autologous stem cell transplantation: A report from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation

BACKGROUND

Leukemia recurrence is a major cause of treatment failure after autologous stem cell transplantation for acute myeloid leukemia (AML). It usually occurs within the first 2 years after transplantation. The goal of the current retrospective study was to assess the follow-up of and characterize risk factors for outcome among patients who survived free of disease recurrence after this period.

METHODS

The analysis included 3567 adults (median age, 45 years) with AML who underwent autografting during the first (86% of patients) or second (14% of patients) complete remission between 1990 and 2008. The stem cell source was the bone marrow in 32% of patients or the peripheral blood in 68% of patients. The median follow-up was 6.9 years.

RESULTS

At 5 years and 10 years after transplantation, the probability of leukemia-free survival was 86% and 76%, respectively; the recurrence incidence was 11% and 16%, respectively; and the nonrecurrence mortality rate was 3% and 8%, respectively. The observed survival was decreased compared with the expected survival of the general European population. In a multivariate analysis, decreased probability of leukemia-free survival was demonstrated for patients who underwent peripheral blood autologous stem cell transplantation; had French-American-British subtypes M0, M6, or M7; and were of an older age. The same factors were found to be associated with an increased risk of disease recurrence. Nonrecurrence mortality was found to be affected by older age.

CONCLUSIONS

The results of the current analysis indicate that late recurrences remain a major concern after autologous stem cell transplantation among patients with AML, indicating the need for close monitoring of minimal residual disease and additional leukemic control measures after transplantation. Cancer 2016;122:1880-7. © 2016 American Cancer Society.

Comparable outcomes between autologous and allogeneic transplant for adult acute myeloid leukemia in first CR

Although allogeneic hematopoietic stem cell transplantation from an HLA-matched sibling donor (MSD) is a potentially curative post-remission treatment for adults with acute myeloid leukemia (AML) in their first CR, transplant-related morbidity and mortality remains a major drawback. We retrospectively compared the outcomes of patients who underwent autologous peripheral blood stem cell transplantation (auto-PBSCT; n=375) with those who underwent allogeneic bone marrow transplantation (allo-BMT; n=521) and allo-PBSCT (n=380) from MSDs for adults with AML/CR1, in which propensity score models were used to adjust selection biases among patients, primary physicians and institutions to overcome ambiguity in the patients' background information. Both the multivariate analysis and propensity score models indicated that the leukemia-free survival rate of auto-PBSCT was not significantly different from that of allo-BMT (hazard ratio (HR), 1.23; 95% confidence interval (CI), 0.92 to 1.66; P=0.16) and allo-PBSCT (HR, 1.13; 95% CI, 0.85-1.51; P=0.40). The current results suggest that auto-PBSCT remains a promising alternative treatment for patients with AML/CR1 in the absence of an available MSD.

Autologous stem cell transplantation for adult acute leukemia in 2015: time to rethink? Present status and future prospects

The use of autologous stem cell transplantation (ASCT) as consolidation therapy for adult patients with acute leukemia has declined over time. However, multiple randomized studies in the past have reported lower relapse rates after autologous transplantation compared with chemotherapy and lower non-relapse mortality rates compared with allogeneic transplantation. In addition, quality of life of long-term survivors is better after autologous transplantation than after allogeneic transplantation. Further, recent developments may improve outcomes of autograft recipients. These include the use of IV busulfan and the busulfan+melphalan combination, better detection of minimal residual disease (MRD) with molecular biology techniques, the introduction of targeted therapies and post-transplant maintenance therapy. Therefore, ASCT may nowadays be reconsidered for consolidation in the following patients if and when they reach a MRD-negative status: good- and at least intermediate-1 risk acute myelocytic leukemia in first CR, acute promyelocytic leukemia in second CR, Ph-positive acute lymphocytic leukemia. Conversely, patients with MRD-positive status or high-risk leukemia should not be considered for consolidation with ASCT.

T-cell-replete haploidentical transplantation versus autologous stem cell transplantation in adult acute leukemia: a matched pair analysis

Adult patients with acute leukemia in need of a transplant but without a genoidentical donor are usually considered upfront for transplantation with stem cells from any other allogeneic source, rather than autologous stem cell transplantation. We used data from the European Society for Blood and Marrow Transplantation and performed a matched pair analysis on 188 T-cell-replete haploidentical and 356 autologous transplants done from January 2007 to December 2012, using age, diagnosis, disease status, cytogenetics, and interval from diagnosis to transplant as matching factors. "Haploidentical expert" centers were defined as having reported more than five haploidentical transplants for acute leukemia (median value for the study period). The median follow-up was 28 months. Multivariate analyses, including type of transplant categorized into three classes ("haploidentical regular", "haploidentical expert" and autologous), conditioning intensity (reduced intensity versus myeloablative conditioning) and the random effect taking into account associations related to matching, showed that non-relapse mortality was higher following haploidentical transplants in expert (HR: 4.7; P=0.00004) and regular (HR: 8.98; P<10(-5)) centers. Relapse incidence for haploidentical transplants was lower in expert centers (HR:0.39; P=0.0003) but in regular centers was similar to that for autologous transplants. Leukemia-free survival and overall survival rates were higher following autologous transplantation than haploidentical transplants in regular centers (HR: 1.63; P=0.008 and HR: 2.31; P=0.0002 respectively) but similar to those following haploidentical transplants in expert centers. We conclude that autologous stem cell transplantation should presently be considered as a possible alternative to haploidentical transplantation in regular centers that have not developed a specific expert program.

High numbers of mobilized CD34+ cells collected in AML in first remission are associated with high relapse risk irrespective of treatment with autologous peripheral blood SCT or autologous BMT

The faster hematopoietic recovery after autologous peripheral blood SCT (APBSCT) in patients with AML may be offset by an increased relapse risk as compared with autologous BMT (ABMT). The EORTC and GIMEMA Leukemia Groups conducted a trial (AML-10) in which they compared, as second randomization, APBSCT and ABMT in first CR patients without an HLA compatible donor. A total of 292 patients were randomized. The 5-year DFS rate was 41% in the APBSCT arm and 46% in the ABMT arm with a hazard ratio (HR) of 1.17; 95% confidence interval=0.85-1.59; P=0.34. The 5-year cumulative relapse incidence was 56% vs 49% (P=0.26), and the 5-year OS 50% and 55% (P=0.6) in the APBSCT and ABMT groups, respectively. APBSCT was associated with significantly faster recovery of neutrophils and platelets, shorter duration of hospitalization, reduced need of transfusion packed RBC and less days of intravenous antibiotics. In both treatment groups, higher numbers of mobilized CD34+ cells were associated with a significantly higher relapse risk irrespective of the treatment given after the mobilization. Randomization between APBSCT and ABMT did not result in significantly different outcomes in terms of DFS, OS and relapse incidence.

Higher percentage of CD34 + CD38- cells detected by multiparameter flow cytometry from leukapheresis products predicts unsustained complete remission in acute myeloid leukemia

Relapse in acute myeloid leukemia (AML) after chemotherapy reflects the persistence of resistant leukemia stem cells (LSCs). These cells have been described in the CD34 + CD38- cell fraction. Leukapheresis products were harvested in 123 patients in morphological complete remission and analyzed by multiparameter flow cytometry. The CD34 + CD38- cell population showed a prognostic impact on survival. Median event-free survival (EFS) was 8.2 months (3-year EFS: 29%) for those with a higher percentage of CD34 + CD38- versus 91.9 months (3-year EFS: 62%) for those with a lower percentage for the entire cohort. These differences were confirmed in patients undergoing autologous stem cell transplant, with median EFS of 7.3 months versus 91.1 months (3-year EFS: 31% vs. 70%). Higher proportions of CD34 + CD38- cells were associated with adverse cytogenetics and with earlier relapses. Higher percentages of CD34 + CD38- cells in apheresis products reflect inadequate in vivo purging and reliably distinguish samples enriched in LSCs from those involving mainly normal cells.

Wilms' tumor gene 1 transcript levels in leukapheresis of peripheral blood hematopoietic cells predict relapse risk in patients autografted for acute myeloid leukemia

Autologous hematopoietic stem cell transplantation (ASCT) is a curative option alternative to allogeneic transplantation for patients with acute myeloid leukemia (AML). Relapse after ASCT can be due to contamination with leukemic blasts of autologous peripheral blood stem cells (PBSCs) collected by leukapheresis (LK). Identification and quantification of a minimal residual disease (MRD) marker in PBSCs could be relevant in determining the relapse risk after ASCT. High levels of the WT1 gene transcript in bone marrow of AML patients after treatment completion predict disease relapse. We evaluated WT1 transcript levels in autologous PBSC from LK used for ASCT in 30 consecutive AML patients in complete remission (CR) and established a correlation with clinical outcome. At diagnosis, all patients had WT1 overexpression. All patients were in morphological and genetic CR at the time of PBSC collection and before ASCT. Real-time quantitative PCR of WT1 was performed in samples of each LK, using TaqMan technology on RNA from mononucleated cells. The median WT1 transcript level in the PBSC graft (WT1-LK) of patients who relapsed was significantly higher than of those who did not relapse after transplantation (P <.0001). We defined a cut-off level of 80 WT1-LK copies/ABL 10e4 copies to discriminate between positive and negative PBSC grafts. The cut-off level was strongly associated with disease recurrence, DFS and OS. Our study represents the largest series of patients evaluating WT1 as a marker of MRD in PBSC LK products using a completely standardized real-time WT1-reverse transcriptase-PCR based assay. These data, if confirmed by prospective study, will help to determine an individual patient's adapted postremission allocation strategy.

Intravenous busulfan for autologous stem cell transplantation in adult patients with acute myeloid leukemia: a survey of 952 patients on behalf of the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation

Oral busulfan is the historical backbone of the busulfan+cyclophosphamide regimen for autologous stem cell transplantation. However intravenous busulfan has more predictable pharmacokinetics and less toxicity than oral busulfan; we, therefore, retrospectively analyzed data from 952 patients with acute myeloid leukemia who received intravenous busulfan for autologous stem cell transplantation. Most patients were male (n=531, 56%), and the median age at transplantation was 50.5 years. Two-year overall survival, leukemia-free survival, and relapse incidence were 67±2%, 53±2%, and 40±2%, respectively. The non-relapse mortality rate at 2 years was 7±1%. Five patients died from veno-occlusive disease. Overall leukemia-free survival and relapse incidence at 2 years did not differ significantly between the 815 patients transplanted in first complete remission (52±2% and 40±2%, respectively) and the 137 patients transplanted in second complete remission (58±5% and 35±5%, respectively). Cytogenetic risk classification and age were significant prognostic factors: the 2-year leukemia-free survival was 63±4% in patients with good risk cytogenetics, 52±3% in those with intermediate risk cytogenetics, and 37 ± 10% in those with poor risk cytogenetics (P=0.01); patients ≤50 years old had better overall survival (77±2% versus 56±3%; P<0.001), leukemia-free survival (61±3% versus 45±3%; P<0.001), relapse incidence (35±2% versus 45±3%; P<0.005), and non-relapse mortality (4±1% versus 10±2%; P<0.001) than older patients. The combination of intravenous busulfan and high-dose melphalan was associated with the best overall survival (75±4%). Our results suggest that the use of intravenous busulfan simplifies the autograft procedure and confirm the usefulness of autologous stem cell transplantation in acute myeloid leukemia. As in allogeneic transplantation, veno-occlusive disease is an uncommon complication after an autograft using intravenous busulfan.

Use of G-CSF to hasten neutrophil recovery after auto-SCT for AML is not associated with increased relapse incidence: a report from the Acute Leukemia Working Party of the EBMT

Application of G-CSF in AML is controversial as leukemic blasts may express receptors interacting with the cytokine, which may stimulate leukemia growth. We retrospectively analyzed the impact of G-CSF use to accelerate neutrophil recovery after auto-SCT on outcome. Adults with AML in first CR autografted between 1994 and 2010 were included. Nine hundred and seventy two patients were treated with G-CSF after auto-SCT whereas 1121 were not. BM and PB were used as a source of stem cells in 454 (22%) and 1639 (78%) cases, respectively. The incidence of relapse at 5 years in the BM-auto-SCT group was 38% for patients receiving post-transplant G-CSF and 43% for those not treated with G-CSF, P=0.46. In the PB-auto-SCT cohort, respective probabilities were 48% and 49%, P=0.49. No impact of the use of G-CSF could be demonstrated with respect to the probability of leukemia-free survival: in the BM-auto-SCT group, 51% for G-CSF(+) and 48% for G-CSF(-), P=0.73; in PB-auto-SCT group, 42% for G-CSF(+) and 43% for G-CSF(-), P=0.83. Although G-CSF administration significantly shortened the neutropenic phase, no beneficial effect was observed with regard to non-relapse mortality. In patients with AML, the use of G-CSF after auto-SCT is not associated with increased risk of relapse irrespective of the source of stem cells used.

Improving results of autologous stem cell transplantation for Philadelphia-positive acute lymphoblastic leukaemia in the era of tyrosine kinase inhibitors: a report from the Acute Leukaemia Working Party of the European Group for Blood and Marrow Transplantation

BACKGROUND

Outcome of Philadelphia-positive acute lymphoblastic leukaemia (Ph+ ALL) improved significantly with the introduction of tyrosine kinase inhibitors (TKIs). Autologous stem cell transplantation (ASCT) has never been considered a standard of care in this setting. The aim of our study was to analyse if results of ASCT improved in the era of TKIs.

PATIENTS AND METHODS

One-hundred and seventy-seven adults with Ph+ ALL treated with ASCT in first complete remission were analysed for the impact of year of transplantation on outcome. Additional analysis was performed including 32 patients for whom detailed data on the use of TKIs and the status of minimal residual disease were collected.

RESULTS

The probability of the overall survival (OS) at 3 years increased from 16% for transplants performed between 1996 and 2001 to 48% between 2002 and 2006 and 57% between 2007 and 2010 (P<.0001). Leukaemia-free survival (LFS) was 11%, 39% and 52%, respectively (P<.0001). Relapse incidence decreased from 70% to 45% and 45% (P=.01), respectively, while non-relapse mortality was 19%, 15% and 3% (P=.08). In a multivariate analysis, year of ASCT was the only independent factor influencing the risk of treatment failure (hazard ratio (HR)=0.37; P<.001). In a subgroup of 22 patients actually treated with TKIs and being in complete molecular remission at the time of ASCT, the LFS rate at 3 years was 65%.

CONCLUSIONS

Results of ASCT for Ph+ ALL improved significantly over time. Prospective, innovative studies are needed to verify the role of ASCT in this patient setting.

Unrelated donor allogeneic transplantation after failure of autologous transplantation for acute myelogenous leukemia: a study from the center for international blood and marrow transplantation research

The survival of patients with relapsed acute myelogenous leukemia (AML) after autologous hematopoietic stem cell transplantation (auto-HCT) is very poor. We studied the outcomes of 302 patients who underwent secondary allogeneic hematopoietic cell transplantation (allo-HCT) from an unrelated donor (URD) using either myeloablative (n = 242) or reduced-intensity conditioning (RIC; n = 60) regimens reported to the Center for International Blood and Marrow Transplantation Research. After a median follow-up of 58 months (range, 2 to 160 months), the probability of treatment-related mortality was 44% (95% confidence interval [CI], 38%-50%) at 1-year. The 5-year incidence of relapse was 32% (95% CI, 27%-38%), and that of overall survival was 22% (95% CI, 18%-27%). Multivariate analysis revealed a significantly better overal survival with RIC regimens (hazard ratio [HR], 0.51; 95% CI, 0.35-0.75; P <.001), with Karnofsky Performance Status score ≥90% (HR, 0.62; 95% CI, 0.47-0.82: P = .001) and in cytomegalovirus-negative recipients (HR, 0.64; 95% CI, 0.44-0.94; P = .022). A longer interval (>18 months) from auto-HCT to URD allo-HCT was associated with significantly lower riak of relapse (HR, 0.19; 95% CI, 0.09-0.38; P <.001) and improved leukemia-free survival (HR, 0.53; 95% CI, 0.34-0.84; P = .006). URD allo-HCT after auto-HCT relapse resulted in 20% long-term leukemia-free survival, with the best results seen in patients with a longer interval to secondary URD transplantation, with a Karnofsky Performance Status score ≥90%, in complete remission, and using an RIC regimen. Further efforts to reduce treatment-related mortaility and relapse are still needed.

Autologous peripheral blood stem cell transplantation with granulocyte colony-stimulating factor combined conditioning regimen as a postremission therapy for acute myelogenous leukemia in first complete remission

We retrospectively analyzed the outcomes of 81 patients with non-M3 acute myelogenous leukemia (AML) in first complete remission (CR1) who were treated with high-dose chemotherapy (HDCT) and autologous peripheral blood stem cell transplantation (Auto-PBSCT) by the Fukuoka Blood and Marrow Transplantation Group between 1989 and 2005. Cytogenetically, 16 patients were defined as good risk, 56 as intermediate risk, and nine as poor risk, following the Southwest Oncology Group criteria. The pre-transplant conditioning regimen consisted of high-dose busulfan, etoposide, and cytarabine (BEA regimen), combined with priming by granulocyte colony-stimulating factor (G-CSF). Disease-free survival (DFS) and overall survival at 5 years were 64.0 % (95 % CI 52.5-73.4) and 66.4 % (95 % CI 54.9-75.6) after Auto-PBSCT at a median follow-up time of 103 months (range 3-240 months), respectively. Two patients died of transplant-related pulmonary complications 6 months after Auto-PBSCT without relapse. The 5-year DFS rates of patients in the genetically good-, intermediate-, and poor-risk groups were 80.8, 64.3, and 33.3 %, respectively, but there was no significant difference statistically among the risk groups (log-rank p = 0.0579). These observations suggest that HDCT supported by Auto-PBSCT with the BEA regimen combined with G-CSF priming is a therapeutic option for postremission therapy of AML in CR1.

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.

The relapse risk of AML patients undergoing autologous transplantation correlates with the stem cell mobilizing potential

Autologous stem cell transplantation (ASCT) is widely used to consolidate first remission in AML. We determined the significance of circulating CD34+ cells at the day of blood stem cell collection in 78 AML patients. Patients mobilizing more than 60,000 CD34+ cells/ml had shorter overall survival (OS; P=0.0274), shorter time to progression (TTP; P=0.0014), and a higher relapse rate (P=0.0177). High levels of CD34+ cells were an independent marker for shorter OS and TTP in a multivariate analysis. These data suggest that ASCT is associated with unfavorable outcome in AML patients with high levels of mobilized peripheral CD34+ cells.

A history of bone marrow transplantation

The last 40 years has seen the emergence of hematopoietic stem cell transplantation as a therapeutic modality for fatal diseases and as a curative option for individuals born with inherited disorders that carry limited life expectancy and poor quality of life. Despite the rarity of many primary immunodeficiency diseases, these disorders have led the way toward innovative therapies and further provide insights into mechanisms of immunologic reconstitution applicable to all hematopoietic stem cell transplants. This article represents a historical perspective of the early investigators and their contributions. It also reviews the parallel work that oncologists and immunologists have undertaken to treat both primary immunodeficiencies and hematologic malignancies.

Autologous transplantation gives encouraging results for young adults with favorable-risk acute myeloid leukemia, but is not improved with gemtuzumab ozogamicin

We report the results of a prospective, randomized phase 3 trial evaluating the use of gemtuzumab ozogamicin (GO) in an intensive consolidation approach in 657 patients 17-60 years of age. Patients in first complete remission (CR1) after cytarabine and standard- or high-dose daunorubicin induction received 2 cycles of consolidation with high-dose cytarabine followed by peripheral blood progenitor cell collection. The 352 patients who entered consolidation were randomized to receive GO (n = 132) or not (n = 138) and then proceeded to autologous hematopoietic cell transplantation (HCT). GO was given to 67 patients. Median follow-up was 50.9 months. Results of the intention-to-treat analysis demonstrated a 4-year disease-free survival (DFS) of 33.6% versus 35.9% (P = .54) and an overall survival (OS) of 41.3% versus 41.9% (P = .52) for those randomized to receive GO versus no GO, respectively. Patients with favorable- and intermediate-risk acute myeloid leukemia (AML) treated with high-dose daunorubicin and autologous HCT had 4-year DFS rates of 60% and 40% and OS rates of 80% and 49.3%, respectively. For younger AML patients in CR1, autologous HCT should be considered in favorable- and intermediate-cytogenetic risk patients who do not have an allogeneic donor. The addition of a single dose of GO in this setting did not improve outcomes.

Mechanisms of G-CSF-mediated hematopoietic stem and progenitor mobilization

Under normal conditions, the great majority of hematopoietic stem/progenitors cells (HSPCs) reside in the bone marrow. The number of HSPCs in the circulation can be markedly increased in response to a number of stimuli, including hematopoietic growth factors, myeloablative agents and environmental stresses such as infection. The ability to 'mobilize' HSPCs from the bone marrow to the blood has been exploited clinically to obtain HSPCs for stem cell transplantation and, more recently, to stimulate therapeutic angiogenesis at sites of tissue ischemia. Moreover, there is recent interest in the use of mobilizing agents to sensitize leukemia and other hematopoietic malignancies to cytotoxic agents. Key to optimizing clinical mobilizing regimens is an understanding of the fundamental mechanisms of HSPC mobilization. In this review, we discuss recent advances in our understanding of the mechanisms by which granulocyte colony-stimulating factor (G-CSF), the prototypical mobilizing agent, induces HSPC mobilization.

Higher incidence of relapse in patients with acute myelocytic leukemia infused with higher doses of CD34+ cells from leukapheresis products autografted during the first remission

The stem cell source for autologous transplantation has shifted from bone marrow to peripheral blood (PB). We previously showed that relapse incidence in patients with acute myelocytic leukemia autografted in first remission (CR1) was greater with PB than bone marrow, and a poorer outcome was associated with a shorter CR1 to PB transplantation interval (≤ 80 days). Leukemic and normal progenitors are CD34(+) and can be concomitantly mobilized; we assessed whether an association exists between the infused CD34(+) cell dose and outcome. The infused CD34(+) cell doses were available for 772 patients autografted more than 80 days after CR1 and were categorized by percentiles. We selected the highest quintile (> 7.16 × 10(6)/kg) as the cutoff point. By multivariate analysis, relapse was more probable in patients who received the highest dose (hazard ratio = 1.48; 95% confidence interval, 1.12-1.95; P = .005), and leukemia-free survival was worse (hazard ratio = 0.72; 95% confidence interval, 0.55-0.93; P = .01). In conclusion, in patients autografted in first remission, relapse was higher and leukemia-free survival lower for those who received the highest CD34(+) PB doses.

Is there a role for autologous stem cell transplantation for patients with acute myelogenous leukemia? A retrospective analysis

For patients with acute myelogenous leukemia (AML) who are unable to secure an acceptable HLA donor, the role of autologous stem cell transplantation (auto-SCT) has remained controversial. Its effectiveness remains unclear as, when analyzed on intention-to-treat strategies, a significant number do not undergo the procedure, whereas others seem to fail therapy from pretransplant recurrences. To improve our counseling to our patients on these 2 therapeutic options, we compared the outcome of patients in first remission of AML who actually underwent autologous or allogeneic transplantation. The choice for the type of graft was based on availability of HLA identical siblings. Patients received myeloablative conditioning followed by allogeneic or autologous cytokine mobilized peripheral blood stem cell transplantation. For prophylaxis of graft-versus-host disease (GVHD), grafts were incubated ex vivo with anti-CD52 antibodies and patients were prescribed cyclosporin until day 90. Patients were stratified by clinical and laboratory factors as well as cytogenetic risk. The endpoints were treatment-related mortality (TRM), disease-free survival (DFS), and overall survival (OS). The median presentation age for both transplant groups was 35 (14-60) years. Of the 112 consecutive patients achieving remission, autologous or allogeneic grafts were transplanted to 43 and 32 patients, respectively. There was no significant difference in the presentation clinical features, laboratory parameters, marrow morphology, or proportion of low and intermediate cytogenetic risk for both transplant options. Treatment mortality as well as relapse rate was similar (14% and 15%; 39% and 27%, respectively). At a median of 1609 and 1819 posttransplant days, 56% and 63% in each group survived. In univariate analysis performance status, cytogenetic risk, morphologic features of dysplasia, blast count, and lactate dehydrogenase (LDH) were significant factors for survival. Although for the entire group there was no difference in survival between both modalities, all patients with unfavorable cytogenetics receiving an autologous graft died of disease recurrence (3-year survival 35% versus 0%; P = .05). We conclude that patients with AML who have low or intermediate cytogenetic risk undergoing myeloablative conditioning followed by autologous or allogeneic T cell-depleted stem cell transplantation appeared to have similar outcome. However, those with unfavorable karyotype are unlikely to be cured with autologous grafts and are candidates for experimental modalities.

A history of bone marrow transplantation

The last 40 years has seen the emergence of hematopoietic stem cell transplantation as a therapeutic modality for fatal diseases and as a curative option for individuals born with inherited disorders that carry limited life expectancy and poor quality of life. Despite the rarity of many primary immunodeficiency diseases, these disorders have led the way toward innovative therapies and further provide insights into mechanisms of immunologic reconstitution applicable to all hematopoietic stem cell transplants. This article represents a historical perspective of the early investigators and their contributions. It also reviews the parallel work that oncologists and immunologists have undertaken to treat both primary immunodeficiencies and hematologic malignancies.

High probability of long-term survival in 2-year survivors of autologous hematopoietic cell transplantation for AML in first or second CR

We describe the long-term outcomes of autologous hematopoietic cell transplantation (HCT) for 315 AML patients in first or second complete remission (CR). All patients were in continuous CR for ≥2 years after HCT. Patients were predominantly transplanted in CR1 (78%) and had good or intermediate cytogenetic risk disease (74%). Median follow-up of survivors was 106 (range, 24-192) months. Overall survival at 10 years after HCT was 94% (95% confidence intervals, 89-97%) and 80% (67-91%) for patients receiving HCT in CR1 and CR2, respectively. The cumulative incidence of relapse at 10 years after HCT was 6% (3-10%) and 10% (3-20%) and that of nonrelapse mortality was 5% (2-9%) and 11% (4-21%), respectively. On multivariate analysis, HCT in CR2 (vs CR1), older age at transplantation and poor cytogenetic risk disease were independent predictors of late mortality and adverse disease-free survival. The use of growth factors to promote engraftment after HCT was the only risk factor for relapse. Relative mortality of these 2-year survivors was comparable to that of age-, race- and gender-matched normal population. Patients who receive autologous HCT for AML in CR1 or CR2 and remain in remission for ≥2 years have very favorable long-term survival. Their mortality rates are similar to that of the general population.