Impact of postremission consolidation chemotherapy on outcome after reduced-intensity conditioning allogeneic stem cell transplantation for patients with acute myeloid leukemia in first complete remission: a report from the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation

More than two courses of pre-transplant consolidation therapy benefits patients with acute myeloid leukemia in the first complete remission who underwent human leukocyte antigen-matched sibling allografts: a multicenter study

BACKGROUND

Although the need for consolidation chemotherapy after successful induction therapy is well established in patients with acute myeloid leukemia (AML) in first complete remission (CR1), the value of consolidation chemotherapy before allogeneic hematopoietic stem cell transplantation remains controversial.

METHODS

We retrospectively compared the effect of the number of pre-transplant consolidation chemotherapies on outcomes of human leukocyte antigen-matched sibling stem cell transplantation (MSDT) for patients with AML in CR1 in multicenters across China. In our study, we analyzed data of 373 AML patients in CR1 from three centers across China.

RESULTS

With a median follow-up of 969 days, patients with ≥ 3 courses of consolidation chemotherapy had higher probabilities of leukemia-free survival (LFS) (85.6% vs . 67.0%, P < 0.001) and overall survival (89.2% vs . 78.5%, P  = 0.007), and better cumulative incidences of relapse (10.5% vs . 19.6%, P  = 0.020) and non-relapse mortality (4.2% vs . 14.9%, P  = 0.001) than those with ≤ 2 courses of consolidation chemotherapy. Pre-transplantation minimal residual disease-negative patients with AML in CR1 who received MSDT with ≥ 3 courses of consolidation chemotherapy had a higher probability of LFS (85.9% vs . 67.7%, P  = 0.003) and a lower cumulative incidence of relapse (9.6% vs . 23.3%, P  = 0.013) than those with ≤ 2 courses.

CONCLUSION

Our results indicate that patients with AML in CR1 who received MSDT might benefit from pre-transplant consolidation chemotherapy.

Impact of pre-transplant induction and consolidation cycles on AML allogeneic transplant outcomes: a CIBMTR analysis in 3113 AML patients

We investigated the impact of the number of induction/consolidation cycles on outcomes of 3113 adult AML patients who received allogeneic hematopoietic cell transplantation (allo-HCT) between 2008 and 2019. Patients received allo-HCT using myeloablative (MAC) or reduced-intensity (RIC) conditioning in first complete remission (CR) or with primary induction failure (PIF). Patients who received MAC allo-HCT in CR after 1 induction cycle had 1.3-fold better overall survival (OS) than 2 cycles to CR and 1.47-fold better than ≥3 cycles. OS after CR in 2 or ≥3 cycles was similar. Relapse risk was 1.65-fold greater in patients receiving ≥3 cycles to achieve CR. After RIC allo-HCT, the number of induction cycles to CR did not affect OS. Compared to CR in 1 cycle, relapse risk was 1.24-1.41-fold greater in patients receiving 2 or ≥3 cycles. For patients receiving only 1 cycle to CR, consolidation therapy prior to MAC allo-HCT was associated with improved OS vs. no consolidation therapy. Detectable MRD at the time of MAC allo-HCT did not impact outcomes while detectable MRD preceding RIC allo-HCT was associated with an increased risk of relapse. For allo-HCT in PIF, OS was significantly worse than allo-HCT in CR after 1-3 cycles.

The mythological chimera and new era of relapse prediction post-transplant

Allogeneic hemopoietic stem cell transplantation is the treatment of choice for high-risk or relapsed acute leukemia. However, unfortunately, relapse post-transplant continues to be the most common cause of treatment failure with 20-80% of patients relapsing based on disease risk and status at transplant. Advances in molecular profiling of different hematological malignancies have enabled us to monitor low level disease before and after transplant and develop a more personalized approach to the management of these disease including early detection post-transplant. While, in general, detectable disease by morphology remains the gold standard to diagnosing relapse, multiple approaches have allowed detection of cancer cells earlier, using peripheral blood-based methods with sensitivities as high as 1:10⁶, together called minimal/measurable residual disease (MRD) detection. However, a in significant number of patients with acute leukemia where no such molecular markers exist it remains challenging to detect early relapse. In such patients who receive transplantation, chimerism monitoring remains the only option. An increase in mixed chimerism in post allogeneic HCT patients has been correlated with relapse in multiple studies. However, chimerism monitoring, while commonly accepted as a tool for assessing engraftment, has not been routinely used for relapse detection, at least in part because of the lack of standardized, high sensitivity, reliable methods for chimerism detection. In this paper, we review the various methods employed for MRD and chimerism detection post-transplant and discuss future trends in MRD and chimerism monitoring from the viewpoint of the practicing transplant physician.

Consolidation in AML: Abundant opinion and much unknown

Consolidation therapy forms the backbone of post-remission therapy for AML and is uniformly accepted as an integral part of therapy designed to achieve long-term survival. The need for post-remission therapy was initially described over four decades ago and has since undergone many variations in terms of dosage, number of cycles and intensity of therapy. There is much empiricism in the current understanding of consolidation therapy and much that has not been rigorously studied. This review will consider the many aspects of consolidation therapy, focusing on the number of cycles, differences between young and older adults, first and subsequent remission as well as therapy prior to an allogeneic transplant. Emphasis will be given to differentiate strategies that are clearly evidence-based from those that have been incorporated into standard of care while bypassing the need for rigorous data-driven approaches. Finally, consideration will be given to the current ability to assess the minimal measureable residual disease and the impact that this may have on therapeutic paradigms, including superseding many of the time-honored prognostic features.

Eradication of Measurable Residual Disease in AML: A Challenging Clinical Goal

In non-promyelocytic (non-M3) AML measurable residual disease (MRD) detected by multi-parameter flow cytometry and molecular technologies, which are guided by Consensus-based guidelines and discover very low leukemic cell numbers far below the 5% threshold of morphological assessment, has emerged as the most relevant predictor of clinical outcome. Currently, it is well-established that MRD positivity after standard induction and consolidation chemotherapy, as well as during the period preceding an allogeneic hematopoietic stem cell transplant (allo-HSCT), portends to a significantly inferior relapse-free survival (RFS) and overall survival (OS). In addition, it has become absolutely clear that conversion from an MRD-positive to an MRD-negative state provides a favorable clinical outcome similar to that associated with early MRD negativity. Thus, the complete eradication of MRD, i.e., the clearance of the few leukemic stem cells-which, due to their chemo-radiotherapy resistance, might eventually be responsible of disease recurrence-has become an un-met clinical need in AML. Nowadays, this goal might potentially be achieved thanks to the development of novel innovative treatment strategies, including those targeting driver mutations, apoptosis, methylation patterns and leukemic proteins. The aim of this review is to analyze these strategies and to suggest any potential combination able to induce MRD negativity in the pre- and post-HSCT period.

Chinese Herbal Medicine for Chemotherapy-Induced Leukopenia: A Systematic Review and Meta-Analysis of High-Quality Randomized Controlled Trials

Aim: We conducted a systematic review of high-quality randomized controlled trials (RCTs) to assess the efficacy and safety of Chinese herbal medicine (CHM) for the treatment of chemotherapy-induced leukopenia (CIL).

Methods: Eight electronic databases were searched from the date of inception to November 4, 2020 for high-quality RCTs that met the requirements of at least four key domains of the Cochrane risk of bias (RoB) tool. RevMan 5.3 was applied for the meta-analysis.

Results: Fourteen RCTs involving 1,053 patients were included. The pooled results showed that CHM + chemotherapy exerted greater beneficial effects on white blood cell (WBC), neutrophil (NEU), hemoglobin (Hb), and platelet (PLT) counts in addition to the Karnofsky performance scale (KPS) score, but showed no significant difference on granulocyte colony-stimulating factor (G-CSF) dosage compared with chemotherapy alone. Placebo (PBO) + chemotherapy and CHM + chemotherapy groups showed no significant differences in terms of reduction of the incidence of neutropenia. CHM + chemotherapy was superior to Western medicine (WM) + chemotherapy in improving the WBC count, KPS, infection amount, G-CSF use rate, and incidence of leukopenia. In addition, no severe adverse events were observed in the 14 RCTs.

Conclusion: CHM in combination with chemotherapy could effectively improve the clinical symptoms of CIL when compared with chemotherapy alone or Western medicine + chemotherapy, except when comparing with PBO + chemotherapy. While CHMs were generally safe for clinical use and exerted no severe side effects in the 14 RCTs, high-quality RCTs with larger sample sizes are essential to reduce study heterogeneity.

Should patients receive consolidation chemotherapy before reduced intensity allogeneic hematopoietic stem cell transplantation for acute myeloid leukemia in first complete remission?

Background:

For acute myeloid leukemia (AML) patients, the role of bridging consolidation chemotherapy after achieving first complete remission (CR1) in the transplant setting is a frequently debated issue. The lack of data from Asian patients led us to conduct this study.

Methods:

We retrospectively studied outcomes of 106 patients in CR1 undergoing allogeneic stem cell transplantation (alloSCT) with reduced intensity conditioning (RIC) based on their exposure to pre-transplant consolidation chemotherapy. There were 35 in the no consolidation group versus 71 in the consolidation group.

Results:

The median relapse free survival (RFS) was 9 months for the no consolidation group and 51 months for consolidation group (p = 0.023). The median overall survival was 32 months for the no consolidation group and not reached for the consolidation group (p = 0.034). Multivariate analysis recognized consolidation and poor cytogenetics as adverse prognostic factors for RFS. Moreover, RFS was better in patients with a shorter time lapse between last chemotherapy and alloSCT in both the no consolidation group and the consolidation group. Consolidation chemotherapy did not negatively affect neutrophil and platelet engraftment, infection rates, or acute graft-versus-host disease (GVHD) incidence. On the other hand, patients undergoing consolidation chemotherapy showed trends towards a more severe degree of chronic GVHD.

Conclusion:

The exposure to consolidation chemotherapy in CR1 prior to alloSCT with RIC conditioning did not negatively impact the outcomes in Korean AML patients, for whom a suitable donor is rarely immediately available. Therefore, post-remission consolidation chemotherapy is a reasonable option if required.

Current and Emerging Therapies for Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is predominantly a disease of older adults and the majority of affected patients succumb to the disease. After decades of slow progress, the last 5 years have witnessed remarkable progress in AML therapy with the approval of multiple highly active and well-tolerated novel therapies. Notable among these are agents targeting driver mutations including FLT3, IDH1/2 as well as the Bcl-2 inhibitor venetoclax. The combination of hypomethylating agents with venetoclax is highly active in AML and has become the standard of care for older patients as well as those with comorbidities. As a result of these advances, a larger proportion of AML patients now achieve complete remissions enabling them to undergo allogeneic hematopoietic cell transplantation with curative intent. Progress is also being made in the field of monoclonal antibodies targeting leukemia antigens and other immunotherapies and many such agents are currently under active investigation.

Value of pre-transplant consolidation chemotherapy in adults with acute lymphoblastic leukemia undergoing allogeneic hematopoietic stem cell transplantation without minimal residual disease in first complete remission

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is recommended for adults acute lymphoblastic leukemia (ALL) with minimal residual disease (MRD) negative during their first complete remission (CR1). However, the role of pre-transplant consolidation chemotherapy remains unclear. We evaluated 78 CR1/MRD-negative patients, the consolidation and non-consolidation groups had similar 5-year OS (74.8% [95% CI: 62.2-87.3%] vs. 74.2% [95% CI: 53.2-95.1%], p = .894), RFS (72.2% [95% CI: 59.6-84.7%] vs. 73.1% [95% CI: 54.2-91.9%], p = .942), CIR (9.4% [95% CI: 9.1-9.7%] vs. 18.9% [95% CI: 17.3-20.4%], p = .376), and NRM (18.4% [95% CI: 17.7-19.0%] vs. 8.0% [95% CI: 7.3-8.6%], p = .375). Multivariable analysis confirmed that high cytogenetic risk independently predicted poor OS and RFS, although pre-transplant consolidation chemotherapy did not predict the prognosis. Based on these findings, we recommend performing transplantation immediately for adult ALL patients after they have achieved CR1/MRD-negative status when there are readily available donors.

Long-term results of reduced-intensity conditioning allogeneic hematopoietic cell transplantation for older patients with acute myeloid leukemia: a retrospective analysis of 10-year follow-up data

The long-term outcomes of allogeneic hematopoietic cell transplantation (HCT) with reduced-intensity conditioning (RIC) remain inconclusive. To address this issue, we conducted a nationwide registry-based study of patients with acute myeloid leukemia (AML) age 50 years or older who underwent allogeneic HCT in complete remission using RIC (n = 284) or myeloablative conditioning (MAC, n = 190) between 2002 and 2007. The median follow-up period for surviving patients was 10.1 years for RIC recipients and 10.4 years for MAC recipients. The 10-year probabilities of overall survival, relapse, and non-relapse mortality were 36.4%, 30.0%, and 35.7% for RIC recipients, and 39.8%, 26.3%, and 35.5% for MAC recipients, respectively. Multivariate analysis revealed that the conditioning intensity did not affect overall mortality (P = 0.184), relapse (P = 0.904), or non-relapse mortality (P = 0.387). For the 218 patients qualifying for propensity score-matched pairing (109 pairs), RIC was found to be associated with similar survival (P = 0.095) and relapse (P = 0.467), and significantly lower non-relapse mortality (P = 0.046) compared with MAC. Our results confirm the long-term efficacy of RIC allogeneic HCT for older patients with AML and mitigate concerns over an increase in late relapse.

[Effect of consolidation before allogeneic hematopoietic stem cell transplantation for non-favorable acute myeloid leukemia patients with first complete remisson and negative minimal residual disease]

Objective: To probe the prognostic value of consolidation chemotherapy in non-favorable acute myeloid leukemia (AML) patients who were candidates for allogeneic hematopoietic stem cell transplantation (allo-HSCT) with first complete remission (CR(1)) and negative minimal residual disease (MRD(-)) . Methods: A retrospective analysis was conducted on 155 patients with non-favorable AML who received allo-HSCT in CR(1)/MRD(-) from January 2010 to March 2019. The survival data were compared between patients who received and those not received pre-transplant consolidation chemotherapy. Results: A total of 102 patients received pre-transplant consolidation chemotherapy (consolidation group) , and 53 cases directly proceeded to allo-HSCT when CR(1)/MRD(-) was achieved (nonconsolidation group) . The median ages were 39 (18-56) years old and 38 (19-67) years old, respectively. Five-year post-transplant overall survival [ (59.3±7.5) % vs (62.2±6.9) %, P=0.919] and relapse-free survival [ (53.0±8.9) % vs (61.6±7.0) %, P=0.936] were not significantly different between the two groups (consolidation vs nonconsolidation) . There was a weak relationship between consolidation therapy and cumulative incidence of relapse [consolidation: (21.9±5.4) % vs nonconsolidation: (18.3±6.0) %, P=0.942], as well as non-relapse mortality [consolidation: (22.4±4.3) % vs nonconsolidation: (28.4±6.5) %,P=0.464]. Multivariate analysis indicated that pre-transplant consolidation and the consolidation courses (< 2 vs ≥2 courses) did not have an impact on allo-HSCT outcomes. Conclusion: Allo-HSCT for candidate patients without further consolidation when CR(1)/MRD(-) was attained was feasible.

The Role of Measurable Residual Disease (MRD) in Hematopoietic Stem Cell Transplantation for Hematological Malignancies Focusing on Acute Leukemia

The significance of measurable residual disease (MRD) in hematopoietic stem cell transplantation (HSCT) is well recognized in different hematological malignancies, but the evidence indicate that pre-transplant MRD status is of particular importance in acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). In ALL, inadequate response at the level of MRD is a commonly accepted risk factor for relapse and thus an indication for allogeneic HSCT. Similarly, growing evidence from the literature strongly suggest that MRD detected by multiparameter flow cytometry or molecular techniques should be also used for risk stratification in AML at the time of HSCT. Despite the well-defined association of MRD and outcomes of HSCT in acute leukemias, there are still many open issues such as the role of additional pre-transplant consolidation for MRD eradication, the ability of HSCT to overcome negative influence of MRD positivity on survival, the impact of conditioning regimen intensity on MRD clearance post HSCT, and transplantation outcomes or the selection of optimal donor with regards to MRD status. In addition, the role of MRD assessment in guiding post-transplant maintenance treatment should also be addressed in prospective trials. These open issues mostly awaiting further clinical studies will be discussed in our current review.

Effect of postremission high dose cytarabine-based consolidation chemotherapy before allogenic stem cell transplantation in outcomes of acute myeloid leukemia patients

BACKGROUND AND AIM

This is a retrospective study aiming to investigate the effect of the number of high dose cytarabine-based chemotherapy (HiDAC) courses in patients with acute myeloid leukemia before allogenic stem cell transplantation (ASCT).

MATERIALS AND METHODS

A total of 110 patients with acute myeloid leukemia who received ASCT between 2001 and 2018 were included in the study.

RESULTS

Of the 110 patients, 25 (23%) patients received one course of HiDAC, 42 (38%) patients received two courses of HiDAC, 34 (31%) patients received three courses of HiDAC and 9 (8%) patients received four courses of HiDAC. Median follow-up for survivors was 71 months (range 4-186) for all patients. The 3-year overall survival for patients who received one course of HiDAC and patients who received more than one course of HiDAC were 49% and 70%, respectively (p = 0.29). The 3-year disease free survival (DFS) for patients who received one course of HiDAC and patients who received more than one course of HiDAC were 38% and 66%, respectively (p = 0.05). There was no statistically significant difference in OS between patients who received one or more than one consolidation chemotherapy. But there was nearly a statistically significant difference between patients who received one or more than one consolidation chemotherapy in DFS.

CONCLUSION

In conclusion, the administration of more than one consolidation chemotherapy may provide longer DFS, however the number of consolidation chemotherapy is not associated with statistically significant differences in overall outcomes.

Effects of post-remission chemotherapy before allo-HSCT for acute myeloid leukemia during first complete remission: a meta-analysis

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is most frequently used to treat acute myeloid leukemia (AML). Whether patients should routinely receive consolidation chemotherapy before proceeding to transplant after achieving first complete remission (CR1) has been a subject of debate. We performed a systematic review and meta-analysis of studies examining the impact of post-remission chemotherapy before allo-HSCT in patients with AML in CR1. Six studies including 1659 patients were included in the meta-analysis. The pooled hazard ratio (HR) for overall survival was 0.9 (95% confidence interval [CI] 0.77-1.05, P = 0.182), and the pooled HR for leukemia-free survival was 0.87 (95% CI 0.75-1.0, P = 0.07). No survival advantage was observed for post-remission chemotherapy before reduced-intensity conditioning or myeloablative conditioning (MAC) allo-HSCT for AML in CR1. The pooled relative risk for relapse incidence (RI) was 1.02 (95% CI 0.82-1.28, P = 0.834). Post-remission chemotherapy before allo-HSCT did not significantly affect the RI in patients with AML in CR1. The analyses revealed no significant benefit of post-remission consolidation chemotherapy in patients who received allo-HSCT. We recommend proceeding to allo-HSCT as soon as CR1 is attained.

When should patients receive consolidation chemotherapy before allogeneic hematopoietic cell transplantation for acute myeloid leukemia in first complete remission?

PURPOSE OF REVIEW

Allogeneic hematopoietic cell transplantation (alloHCT) is a potentially curative therapy for patients with acute myeloid leukemia. Despite the associated graft-versus-leukemia effect, leukemia relapse remains the most common cause of treatment failure after alloHCT. Here, we review the available data on whether there is an advantage in providing pretransplant consolidation chemotherapy prior to alloHCT.

RECENT FINDINGS

Randomized controlled studies are lacking. Data derive largely from four large retrospective registry studies. These analyses are consistent in demonstrating the lack of any survival benefit for pretransplant consolidation chemotherapy once a patient achieves a complete remission and a donor is readily available. These results are valid across conditioning regimen intensities, donor sources, and doses of cytarabine administered during consolidation.

SUMMARY

Available evidence suggests that patients with acute myeloid leukemia in first complete remission for whom a suitable donor is readily available should not be given pretransplant consolidation before proceeding to alloHCT, regardless of conditioning regimen intensity and that transplantation should be offered promptly at the time remission is achieved without undue delay. Nevertheless, patients for whom a suitable donor is not readily available after achieving first remission, should probably receive 'bridging' consolidation chemotherapy while waiting for a donor to be identified in an attempt to decrease the risk of early disease recurrence before transplantation. The role of minimal residual disease and genetic markers in directing consolidation choices are unclear to date.

Consolidation chemotherapy prior to hematopoietic cell transplantation for adults with acute myeloid leukemia in first remission

Whether patients with acute myeloid leukemia (AML) should receive routine consolidation chemotherapy prior to transplant remains a significant question. Consolidation therapy may be advisable in the face of transplant delays, such as donor identification, insurance clearance, or transplant center scheduling, to prevent relapse prior to transplant. However, in cases where physicians have a choice, the question of the value of consolidation chemotherapy continues to be debated. This paper reviews the value of consolidation therapy in 4 different transplant settings.

Sequential Intensified Conditioning Regimen Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients with Intermediate- or High-Risk Acute Myeloid Leukemia in Complete Remission: A Study from the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation

Post-transplant relapse is the leading cause of treatment failure in acute myeloid leukemia (AML) patients after reduced-intensity conditioning allogeneic hematopoietic stem cell transplantation (allo-HSCT). To improve their outcome, we evaluated the outcome of a sequential intermediate-intensity conditioning regimen combining fludarabine, cytosine arabinoside, amsacrine, cyclophosphamide, and either total body irradiation or busulfan (FLAMSA) in patients with intermediate or high-risk AML in first or second complete remission (CR). A total of 265 patients (median age, 55 years; range, 19 to 76) with AML who underwent allo-HSCT using a FLAMSA regimen were included. At the time of transplant, 216 (81.5%) were in CR1 and 49 (18.5%) in CR2. Cytogenetic was intermediate in 114 (43%) and poor in 42 (15.8%) patients, whereas 109 patients (41.1%) had a secondary AML. With a median follow-up of 46 months (range, 1 to 145), the Kaplan-Meier estimate of overall and leukemia-free survival at 2 years were 56.1% (95% CI, 49.7% to 62.6%) and 52.8% (95% CI, 46.4% to 59.2%), respectively. At 2 years, the cumulative incidences of relapse and nonrelapse mortality were 22.8% (95% CI, 17.6% to 28.4%) and 24.0% (95% CI, 18.8% to 29.5%), respectively. In multivariate analysis, patient age and cytogenetics were the only parameters with a significant impact on overall survival. These data suggest that the FLAMSA sequential intermediate conditioning regimen provides an efficient disease control in intermediate- and high-risk AML patients, including those in CR2 and with secondary AML.

Pretransplant NPM1 MRD levels predict outcome after allogeneic hematopoietic stem cell transplantation in patients with acute myeloid leukemia

The objective was to evaluate the prognostic impact of pre-transplant minimal residual disease (MRD) as determined by real-time quantitative polymerase chain reaction in 67 adult NPM1-mutated acute myeloid leukemia patients receiving allogeneic hematopoietic stem cell transplantation (HSCT). Twenty-eight of the 67 patients had a FLT3-ITD (42%). Median age at transplantation was 54.7 years, median follow-up for survival from time of allografting was 4.9 years. At transplantation, 31 patients were in first, 20 in second complete remission (CR) and 16 had refractory disease (RD). Pre-transplant NPM1 MRD levels were measured in 39 CR patients. Overall survival (OS) for patients transplanted in CR was significantly longer as compared to patients with RD (P=0.004), irrespective of whether the patients were transplanted in first or second CR (P=0.74). There was a highly significant difference in OS after allogeneic HSCT between pre-transplant MRD-positive and MRD-negative patients (estimated 5-year OS rates of 40 vs 89% P=0.007). Multivariable analyses on time to relapse and OS revealed pre-transplant NPM1 MRD levels >1% as an independent prognostic factor for poor survival after allogeneic HSCT, whereas FLT3-ITD had no impact. Notably, outcome of patients with pre-transplant NPM1 MRD positivity >1% was as poor as that of patients transplanted with RD.

Reduced intensity conditioning allogeneic hematopoietic cell transplantation for adult acute myeloid leukemia in complete remission - a review from the Acute Leukemia Working Party of the EBMT

Acute myeloid leukemia is the most common indication for an allogeneic hematopoietic cell transplant. The introduction of reduced intensity conditioning has expanded the recipient pool for transplantation, which has importantly made transplant an option for the more commonly affected older age groups. Reduced intensity conditioning allogeneic transplantation is currently the standard of care for patients with intermediate or high-risk acute myeloid leukemia and is now most often employed in older patients and those with medical comorbidities. Despite being curative for a significant proportion of patients, post-transplant relapse remains a challenge in the reduced intensity conditioning setting. Herein we discuss the studies that demonstrate the feasibility of reduced intensity conditioning allogeneic transplants, compare the outcomes of reduced intensity conditioning versus chemotherapy and conventional myeloablative conditioning regimens, describe the optimal donor and stem cell source, and consider the impact of post-remission consolidation, comorbidities, center experience, and more intensive (reduced toxicity conditioning) regimens on outcomes. Additionally, we discuss the need for further prospective studies to optimize transplant outcomes.

Is the D14 bone marrow in acute myeloid leukemia still the gold standard?

PURPOSE OF REVIEW

Early bone marrow evaluation on day 14 of induction is common practice assisting in decision making regarding reinduction need in acute myeloid leukemia (AML). Studies exploring day 14 bone marrow false positive and negative rates yielded diverse data, and a highly specific method for early bone marrow evaluation is warranted. Given the improved induction-associated death rate, the risk of redundant reinduction administered to patients anticipating remission with one induction cycle may be outweighed by the benefit from the potential reduction in the falsely interpreted nadir bone marrow. The purpose of this review is to analyze current evidence on ways to optimize early bone marrow evaluation during induction in AML.

RECENT FINDINGS

Day 14 bone marrow blast count is affected by patient's age, leukemic risk, and induction regimen, and its remission prediction power is enhanced if more stringent cutoffs are used to define significant residual blast numbers or if morphologic bone marrow evaluation is performed on day 5 of induction.

SUMMARY

Early bone marrow evaluation has a potential to personalize the induction regimen, but because of limitations of day 14 bone marrow results, earlier bone marrow evaluation or the use of flow cytometry to detect minor blast populations may improve remission prediction in AML.

Infusion of allogeneic umbilical cord blood hematopoietic stem cells in patients with chemotherapy-related myelosuppression

Chemotherapy-induced myelosuppression is one of the main problems in the treatment of cancer. In the present study, the effects of allogeneic umbilical cord blood hematopoietic stem cell (UCB-HSC) infusion were investigated on the treatment of chemotherapy-related myelosuppression. In total, 65 patients (male, 42; female, 23) diagnosed with chemotherapy-related myelosuppression were included in the study. The majority of the patients were classified with stage II myelosupression at enrolment, and an average concentration of 7.07×10⁹/l UCB-HSCs were transfused through the peripheral vein. The minimum values of the white blood cell (WBC) count, hemoglobin (Hb) level, platelet (PLT) count and Karnofsky performance status (KPS) scores were recorded prior to and between days 7 and 14 following UCB-HSC infusion. When assessing the overall data, the results revealed that the mean WBC and PLT counts increased significantly following UCB-HSC infusion. However, the subgroup analyses based on gender and KPS score revealed that UCB-HSC infusion was more successful in male patients and those with a higher KPS score. Spearman's correlation analysis revealed a linear correlation between the number of transfused UCB-HSCs and the changes in the WBC and PLT counts following treatment. In conclusion, the results indicated that peripheral vein infusion of non-human leukocyte antigen matched UCB-HSCs can markedly improve chemotherapy-related myelosuppression in a safe and effective manner.

Impact of early remission by induction therapy on allogeneic stem cell transplantation for acute myeloid leukemia with an intermediate-risk karyotype in first complete remission

For patients with acute myeloid leukemia (AML) early achievement of remission during induction treatment is an important predictor for long-term outcome irrespective of the type of consolidation therapy employed. Here, we retrospectively examined the prognostic impact of early remission (ER) vs. delayed remission (DR) in a cohort of 132 AML patients with an intermediate-risk karyotype undergoing allogeneic stem cell transplantation (alloSCT) in first complete remission (CR1). In contrast to patients showing DR, patients achieving ER had a significantly higher 3-yr overall survival (OS) and disease-free survival (DFS) of 76% vs. 54% (P = 0.03) and 76% vs. 53% (P = 0.03). Likewise, 3 yr after alloSCT the cumulative incidence of relapse (CI-R) was significantly lower in the ER subgroup as compared to patients achieving DR, that is, 10% vs. 35% (P = 0.004), whereas non-relapse mortality (NRM) did not differ significantly. Multivariate analysis identified DR as an independent prognosticator for an inferior DFS (HR 3.37, P = 0.002) and a higher CI-R (HR 3.55, P = 0.002). Taken together, these data may indicate that the rapid achievement of remission predicts a favorable outcome in patients with intermediate-risk AML undergoing alloSCT in CR1. In turn, the adverse effect of DR may not be fully overcome by alloSCT.

Allogeneic hematopoietic cell transplantation for acute myeloid leukemia during first complete remission: a clinical perspective

Allogeneic hematopoietic cell transplantation (HCT) is the most potent therapy for preventing relapse of acute myeloid leukemia (AML). Although its efficacy is compromised by a high risk of treatment-related morbidity and mortality, an accumulating body of evidence has led to the general recommendation favoring allogeneic HCT from a matched sibling donor during first complete remission (CR1) for younger patients with cytogenetically intermediate- or high-risk AML. Over the past few decades, this field has seen a great many advancements. The indications for allogeneic HCT have been refined by taking into account the molecular profiles of leukemic cells and the degree of comorbidities. The introduction of high-resolution human leukocyte antigen-typing technology and advances in immunosuppressive therapy and supportive care measures have improved outcomes in alternative donor transplantation, while the parallel growth of unrelated donor registries and greater use of umbilical cord blood and haploidentical donors have considerably improved the chance of finding an alternative donor. The development of reduced-intensity and non-myeloablative conditioning has made it possible to receive allogeneic HCT for patients who might once have been considered ineligible due to advanced age or comorbidities. Thanks to these advances, the role of allogeneic HCT during CR1 has become progressively more important in the treatment of AML.