Reduced intensity conditioning allogeneic stem cell transplantation for patients with acute myeloid leukemia: long term results of a ‘donor’ versus ‘no donor’ comparison

A multicenter study of posttransplantation low-dose inotuzumab ozogamicin to prevent relapse of acute lymphoblastic leukemia

ABSTRACT

The curative potential of allogeneic hematopoietic transplantation (allo-HCT) in patients with acute lymphoblastic leukemia (ALL) is hampered by relapse. Inotuzumab ozogamicin (INO) is an anti-CD22 monoclonal antibody bound to calicheamicin, which has significant activity against ALL. We hypothesized that low-dose INO would be safe and feasible after allo-HCT. Therefore, we conducted a phase 1 study to determine the dose and safety in this setting. Patients were eligible if they were aged 16 to 75 years, had undergone allo-HCT for CD22+ ALL, were in complete remission (CR) after allo-HCT, had high risk of recurrence, were between day 40 and 100 after allo-HCT with adequate graft function, and did not have a history of sinusoidal obstruction syndrome (SOS). The objectives of this trial were to define INO maximum tolerated dose (MTD), to determine post-allo-HCT INO safety, and to measure 1-year progression-free survival (PFS). The trial design followed a "3+3" model. The treatment consisted of INO given on day 1 of 28-day cycles. Dose levels were 0.3 mg/m2, 0.4 mg/m2, 0.5 mg/m2, and 0.6 mg/m2. Median age was 44 years (range, 17-66 years; n = 18). Disease status at transplantation was first CR (n = 14) or second CR or beyond (n = 4). Preparative regimen was of reduced intensity in 72% of patients who received transplantation. Most common toxicity was thrombocytopenia. There were no instances of SOS; the MTD was 0.6 mg/m2. One-year nonrelapse mortality was 5.6%. With a median follow-up of 18.1 months (range, 8.6-59 months) 1-year post-allo-HCT PFS and overall survival is 89% and 94%, respectively. Low-dose INO has a favorable safety profile and was associated with high rates of 1-year PFS. This trial was registered at www.clinicaltrials.gov as #NCT03104491.

Transplantation Referral Patterns for Patients with Newly Diagnosed Higher-Risk Myelodysplastic Syndromes and Acute Myeloid Leukemia at Academic and Community Sites in the Connect® Myeloid Disease Registry: Potential Barriers to Care

Hematopoietic stem cell transplantation (HCT) is indicated for patients with higher-risk (HR) myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Age, performance status, patient frailty, comorbidities, and nonclinical factors (eg, cost, distance to site) are all recognized as important clinical factors that can influence HCT referral patterns and patient outcomes; however, the proportion of eligible patients referred for HCT in routine clinical practice is largely unknown. This study aimed to assess patterns of consideration for HCT among patients with HR-MDS and AML enrolled in the Connect® Myeloid Disease Registry at community/government (CO/GOV)- or academic (AC)-based sites, as well as to identify factors associated with rates of transplantation referral. We assessed patterns of consideration for and completion of HCT in patients with HR-MDS and AML enrolled between December 12, 2013, and March 6, 2020, in the Connect Myeloid Disease Registry at 164 CO/GOV and AC sites. Registry sites recorded whether patients were considered for transplantation at baseline and at each follow-up visit. The following answers were possible: "considered potentially eligible," "not considered potentially eligible," or "not assessed." Sites also recorded whether patients subsequently underwent HCT at each follow-up visit. Rates of consideration for HCT between CO/GOV and AC sites were compared using multivariable logistic regression analysis with covariates for age and comorbidity. Among the 778 patients with HR-MDS or AML enrolled in the Connect Myeloid Disease Registry, patients at CO/GOV sites were less likely to be considered potentially eligible for HCT than patients at AC sites (27.9% versus 43.9%; P < .0001). Multivariable logistic regression analysis with factors for age (<65 versus ≥65 years) and ACE-27 comorbidity grade (<2 versus ≥2) showed that patients at CO/GOV sites were significantly less likely than those at AC sites to be considered potentially eligible for HCT (odds ratio, 1.6, 95% confidence interval, 1.1 to 2.4; P = .0155). Among patients considered eligible for HCT, 45.1% (65 of 144) of those at CO/GOV sites and 35.7% (41 of 115) of those at AC sites underwent transplantation (P = .12). Approximately one-half of all patients at CO/GOV (50.1%) and AC (45.4%) sites were not considered potentially eligible for HCT; the most common reasons were age at CO/GOV sites (71.5%) and comorbidities at AC sites (52.1%). Across all sites, 17.4% of patients were reported as not assessed (and thus not considered) for HCT by their treating physician (20.7% at CO/GOV sites and 10.7% at AC sites; P = .0005). These findings suggest that many patients with HR-MDS and AML who may be candidates for HCT are not receiving assessment or consideration for transplantation in clinical practice. In addition, treatment at CO/GOV sites and age remain significant barriers to ensuring that all potentially eligible patients are assessed for HCT.

Feasibility, safety, and efficacy of early prophylactic donor lymphocyte infusion after T cell-depleted allogeneic stem cell transplantation in acute leukemia patients

Prophylactic donor lymphocyte infusion (DLI) starting at 6 months after T cell-depleted allogeneic stem cell transplantation (TCD-alloSCT) can introduce a graft-versus-leukemia (GvL) effects with low risk of severe graft-versus-host-disease (GvHD). We established a policy to apply low-dose early DLI at 3 months after alloSCT to prevent early relapse. This study analyzes this strategy retrospectively. Of 220 consecutive acute leukemia patients undergoing TCD-alloSCT, 83 were prospectively classified to have a high relapse risk and 43 were scheduled for early DLI. 95% of these patients received freshly harvested DLI within 2 weeks of the planned date. In patients transplanted with reduced intensity conditioning and an unrelated donor, we found an increased cumulative incidence of GvHD between 3 and 6 months after TCD-alloSCT for patients receiving DLI at 3 months compared to patients who did not receive this DLI (0.42 (95%Confidence Interval (95% CI): 0.14-0.70) vs 0). Treatment success was defined as being alive without relapse or need for systemic immunosuppressive GvHD treatment. The five-year treatment success in patients with acute lymphatic leukemia was comparable between high- and non-high-risk disease (0.55 (95% CI: 0.42-0.74) and 0.59 (95% CI: 0.42-0.84)). It remained lower in high-risk acute myeloid leukemia (AML) (0.29 (95% CI: 0.18-0.46)) than in non-high-risk AML (0.47 (95% CI: 0.42-0.84)) due to an increased relapse rate despite early DLI.

Allogeneic Hematopoietic Stem Cell Transplantation for Older Patients With Acute Myeloid Leukemia

OPINION STATEMENT

Acute myelogenous leukemia (AML) in the elderly is complex and has a poor prognosis, often characterized by higher risk cytogenetic and molecular features compared to that in younger patients. Rates of transplant have been limited by concern related to non-relapse mortality, as older patients have historically been considered medically unfit for the transplantation process. Reduced-intensity conditioning (RIC) for hematopoietic stem cell transplantation (HSCT) has been shown to provide similar efficacy to myeloablative methods, with decreased non-relapse mortality in the elderly and improved efficacy over non-transplant approaches with cytotoxic chemotherapy alone. Targeted non-cytotoxic and modified cytotoxic agents have emerged to further improve transplant outcomes for older AML patients. Validated comorbidity indices are useful tools to assess an individual's fitness for undergoing HSCT rather than chronological age alone. We believe HSCT is the primary curative treatment approach for many older AML patients, taking into account risk and comorbidities, particularly given the tendency of leukemia in this population to harbor an unfavorable disease profile. We use RIC and advocate for the addition of targeted agents if applicable. With continuing data in support of transplant for older AML patients, we anticipate that transplant rates in this population will continue to rise.

Impact of Allogeneic Stem Cell Transplantation in First Complete Remission in Acute Myeloid Leukemia: A National Population-Based Cohort Study

To examine the outcomes of allogeneic stem cell transplantation (HSCT) in first complete remission (CR1) compared with chemotherapy alone in a population-based setting, we identified a cohort of patients with acute myeloid leukemia (AML) aged 15 to 70 years diagnosed between 2000 and 2014 in Denmark. Using the Danish National Acute Leukemia Registry, we compared relapse risk, relapse-free survival (RFS), and overall survival (OS) between patients with unfavorable cytogenetic features receiving postremission therapy with conventional chemotherapy only versus those undergoing HSCT in CR1. To minimize immortal time bias, we performed Cox proportional hazards regression, included date of allogeneic HSCT as a time-dependent covariate, and stratified the results by age (<60 or ≥60 years) and cytogenetic risk group. Overall, 1031 patients achieved a CR1. Of these, 196 patients (19%) underwent HSCT. HSCT was associated with a lower relapse rate (24% versus 49%) despite a similar median time to relapse (287 days versus 265 days). In all subgroups, the risk of relapse was lower and both RFS and OS were superior in recipients of HSCT (OS, adjusted mortality ratios: all patients, .54 [95% confidence interval (CI), .42-.71]; patients age <60 years, .58 [95% CI, .42-.81]; patients age ≥60 years, .42 [95% CI, .26-.69]; patients with intermediate-risk cytogenetics, .63 [95% CI, .43-.87]; patients with adverse-risk cytogenetics, .40 [95% CI, .24-.67]). In conclusion, in this population-based nationwide cohort study, HSCT was associated with improved survival in both younger and older patients and in patients with both intermediate and adverse cytogenetic risk.

Autologous Hematopoietic Stem Cell Transplantation for Adults With Acute Myeloid Leukemia

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) remains the most efficacious therapy in patients with acute leukemia. For older patients and those lacking a related HLA-compatible donor, autologous transplantation (auto-HSCT) is a valid alternative therapeutic option.

METHODS

From 1997 until 2014 in the Department of Hematooncology and Bone Marrow Transplantation, Medical University of Lublin, Poland, 29 auto-HSCT were performed in patients with acute myeloid leukemia (AML; 15 men and 14 women; median age, 52.2 years). The following FAB types of AML were diagnosed: M0, 3; M1, 4; M2, 6; M4, 10; and M5, 6. Patients with AML were classified into 3 cytogenetic prognostic groups: high risk, 9; intermediate risk, 16; and low risk, 4. Twenty-five were in first complete remission and 4 in second complete remission. The peripheral HSCs mobilized after chemotherapy (mainly second course of consolidation) and granulocyte colony-stimulating factor were the source of the stem cells in all cases. The median number of infused CD34+ cells was 3.58 × 10(6)/kg. The conditioning regimen was busulfan and cyclophosphamide in all patients with AML. The intravenous form of busulfan was applied in the last 15 patients.

RESULTS

The median time for absolute neutrophil count recovery >0.5 × 10(9)/L and for platelet count >20.0 × 10(9)/L was 12 and 16.5 days, respectively. Treatment-related mortality rate in the whole group was 3.4% (1 patient with sepsis in the aplastic period). The median follow-up time of survivors was 21.9 months (range, 11.7-142.4). The 3-year projected disease-free survival and overall survival rates were 60% and 68%, respectively.

CONCLUSIONS

Our data confirm that auto-HSCT is a valuable therapeutic option for patients with AML, especially older patients and those lacking related HLA-compatible donors.

Acute myeloid leukemia: 2016 Update on risk-stratification and management

Evidence suggest that even patients aged 70 or above benefit from specific AML therapy. The fundamental decision in AML then becomes whether to recommend standard or investigational treatment. This decision must rest on the likely outcome of standard treatment. Hence we review factors that predict treatment related mortality and resistance to therapy, the latter the principal cause of failure even in patients aged 70 or above. We emphasize the limitations of prediction of resistance based only on pre- treatment factors and stress the need to incorporate post-treatment factors, for example indicators of minimal residual disease. We review various newer therapeutic options and considerations that underlie the decision to recommend allogeneic hematopoietic cell transplant. Am. J. Hematol. 91:825-846, 2016. © 2016 Wiley Periodicals, Inc.

Hematopoietic stem cell transplantation for patients with AML in first complete remission

Postremission therapy in patients with acute myeloid leukemia (AML) may consist of continuing chemotherapy or transplantation using either autologous or allogeneic stem cells. Patients with favorable subtypes of AML generally receive chemotherapeutic consolidation, although recent studies have also suggested favorable outcome after hematopoietic stem cell transplantation (HSCT). Although allogeneic HSCT (alloHSCT) is considered the preferred type of postremission therapy in poor- and very-poor-risk AML, the place of alloHSCT in intermediate-risk AML is being debated, and autologous HSCT is considered a valuable alternative that may be preferred in patients without minimal residual disease after induction chemotherapy. Here, we review postremission transplantation strategies using either autologous or allogeneic stem cells. Recent developments in the field of alternative donors, including cord blood and haploidentical donors, are highlighted, and we discuss reduced-intensity alloHSCT in older AML recipients who represent the predominant category of patients with AML who have a high risk of relapse in first remission.

Phase II Trial of Reduced-Intensity Busulfan/Clofarabine Conditioning with Allogeneic Hematopoietic Stem Cell Transplantation for Patients with Acute Myeloid Leukemia, Myelodysplastic Syndromes, and Acute Lymphoid Leukemia

Clofarabine has potent antileukemia activity and its inclusion in reduced-intensity conditioning (RIC) allogeneic hematopoietic stem cell transplantation (HSCT) for acute leukemia could potentially improve outcomes. We conducted a phase II study of busulfan (.8 mg/kg i.v. twice daily on days -5, -4, -3, and -2) with clofarabine (40 mg/m(2) i.v. daily on days -5, -4, -3, and -2) conditioning before allogeneic 8/8 HLA-matched related or unrelated HSCT. The primary endpoint was donor neutrophil engraftment by day +40. Secondary endpoints included nonrelapse mortality (NRM), acute and chronic graft-versus-host disease (GVHD), progression-free survival (PFS), and overall survival (OS). Thirty-four patients (acute myeloid leukemia [AML], n = 25; myelodysplastic syndromes, n = 5; and acute lymphoid leukemia, n = 4) were enrolled. Day 40+ engraftment with donor chimerism was achieved in 33 of 34 patients with 1 patient dying before count recovery. Day 100 and 1-year NRM were 5.9% (95% confidence interval [CI], 1.0 to 17.4) and 24% (95% CI, 11 to 39), respectively. The 2-year relapse rate was 26% (95% CI, 13 to 42). Cumulative incidences of acute and chronic GVHD were 21% and 44%, respectively. The 2-year PFS was 50% (95% CI, 32 to 65) and OS was 56% (95% CI, 38 to 71). For patients with AML in first complete remission, 2-year PFS and OS were both 82% (95% CI, 55 to 94). RIC with busulfan and clofarabine leads to successful engraftment with acceptable rates of NRM and GVHD.

Efficacy of Allogeneic Hematopoietic Stem Cell Transplantation in Intermediate-Risk Acute Myeloid Leukemia Adult Patients in First Complete Remission: A Meta-Analysis of Prospective Studies

Hematopoietic stem cell transplantation (HSCT) and consolidation chemotherapy have been used to treat intermediate-risk acute myeloid leukemia (AML) patients in first complete remission (CR1). However, it is still unclear which treatments are most effective for these patients. The aim of our study was to analyze the relapse-free survival (RFS) and overall survival (OS) benefit of allogeneic HSCT (alloHSCT) for intermediate-risk AML patients in CR1. A meta-analysis of prospective trials comparing alloHSCT to non-alloHSCT (autologous HSCT [autoHSCT] and/or chemotherapy) was undertaken. We systematically searched PubMed, Embase, and the Cochrane Library though October 2014, using keywords and relative MeSH or Emtree terms, 'allogeneic'; 'acut*' and 'leukem*/aml/leukaem*/leucem*/leucaem*'; and 'nonlympho*' or 'myelo*'. A total of 7053 articles were accessed. The primary outcomes were RFS and OS, while the secondary outcomes were treatment-related mortality (TRM) and relapse rate (RR). Hazard ratios (HR) and 95% confidence intervals (CI) were calculated for each outcome. The primary outcomes were RFS and OS, while the secondary outcomes were TRM and RR. We included 9 prospective controlled studies including 1950 adult patients. Patients with intermediate-risk AML in CR1 who received either alloHSCT or non-alloHSCT were considered eligible. AlloHSCT was found to be associated with significantly better RFS, OS, and RR than non-alloHSCT (HR, 0.684 [95% CI: 0.48, 0.95]; HR, 0.76 [95% CI: 0.61, 0.95]; and HR, 0.58 [95% CI: 0.45, 0.75], respectively). TRM was significantly higher following alloHSCT than non-alloHSCT (HR, 3.09 [95% CI: 1.38, 6.92]). However, subgroup analysis showed no OS benefit for alloHSCT over autoHSCT (HR, 0.99 [95% CI: 0.70, 1.39]). In conclusion, alloHSCT is associated with more favorable RFS, OS, and RR benefits (but not TRM outcomes) than non-alloHSCT generally, but does not have an OS advantage over autoHSCT specifically, in patients with intermediate-risk AML in CR1.

Acute myeloid leukemia: 2014 update on risk-stratification and management

OVERVIEW

Evidence suggests that even patients aged 70 or above benefit from specific AML therapy. The fundamental decision in AML then becomes whether to recommend standard or investigational treatment. This decision must rest on the likely outcome of standard treatment. Hence we review factors that predict treatment related mortality and resistance to therapy, the latter the principal cause of failure even in patients aged 70 or above. We emphasize the limitations of prediction of resistance based only on pre-treatment factors and stress the need to incorporate post-treatment factors, for example indicators of minimal residual disease. We review various newer therapeutic options and considerations that underlie the decision to recommend allogeneic hematopoietic cell transplant.

Quality of life and outcomes in patients⩾60 years of age after allogeneic hematopoietic cell transplantation

Hematopoietic cell transplantation (HCT) has become an established standard of care for many older patients with hematologic malignancies. The effect of transplantation on the quality of life (QOL) of older patients, however, has not been well studied. We thus analyzed QOL in patients ⩾60 undergoing an allogeneic HCT compared with patients <60 years. Prospective psychometric instruments were administered to 351 patients who underwent HCT from 2003 to 2010. Psychometric data were assessed longitudinally by validated questionnaires: Functional Assessment of Cancer Therapy-Bone Marrow Transplant (FACT-BMT), Coping Inventory and the Profile of Mood State-Short Form. Patients ⩾60 reported better social (P=0.006) and functional well-being (P=0.05) with FACT assessment, and had better total scores, (P=0.043) across all time points. When adjusted for baseline QOL scores as a covariate, social well-being remained significantly better, whereas the other scores became non-significant. With a median follow-up of 49 months, there were no significant differences in OS, relapse-free survival, relapse or chronic GVHD. This study provides further evidence that advanced age should not be a barrier in the decision to pursue allogeneic HCT. Older patients achieved comparable QOL when compared with younger patients.

Alternative novel therapies for the treatment of elderly acute myeloid leukemia patients

With a median age at diagnosis of approximately 65-70 years, acute myeloid leukemia (AML) represents a major therapeutic challenge in the elderly. Only 30-35% of elderly patients with AML are considered eligible for intensive chemotherapy and do actually receive it. However, the long-term benefit associated with intensive chemotherapy remains marginal, and the overall outcome for this population remains poor. The remaining 60-65% of elderly AML patients receives supportive care only. Nevertheless, several studies have indicated that patients who receive any therapy had a better outcome if compared with patients who receive supportive care only. Thus, the development of novel, less toxic, targeted agents is offering new options to older AML patients who are unfit for intensive approaches. In the present review, we will report on the results achieved using intensive chemotherapy and novel agents, and will describe some of the new strategies under development for treating older AML patients.

Intentional donor lymphocyte-induced limited acute graft-versus-host disease is essential for long-term survival of relapsed acute myeloid leukemia after allogeneic stem cell transplantation

The prognosis of patients with relapsed acute myeloid leukemia after allogeneic transplantation is poor. We hypothesized that initial disease control by effective cytoreduction, followed by rapid induction of a profound allo-immune response by donor-lymphocyte infusion during the neutropenic phase, is essential for long-term survival. Additional interferon-α was administered when no acute graft-versus-host-disease occurred within 3 weeks after donor-lymphocyte infusion. Overall, 44 patients with relapsed acute myeloid leukemia were assessed; 26 had relapsed after myeloablative conditioning and 18 after reduced-intensity conditioning. Of these 44 patients, seven were not eligible for cytoreductive treatment because of poor performance status (n=3) or severe graft-versus-host-disease (n=4) at the time of relapse. Patients with smoldering relapses (n=5) received donor-lymphocyte infusion only. Thirty-two patients received cytoreductive treatment, followed by donor-lymphocyte infusion in 22 patients. Reasons for not receiving donor-lymphocyte infusion were chemotherapy-related death (n=1) and chemotherapy-refractory disease (n=9). The 2-year overall survival rate after donor-lymphocyte infusion was 36% (95% confidence-interval: 16-57%). The impact of acute graft-versus-host-disease on survival was calculated with a Cox-regression model including onset of acute graft-versus-host-disease as a time-dependent variable. Development of grade 1-3, but not grade 4, acute graft-versus-host-disease was associated with superior survival as compared to absence of graft-versus-host-disease (hazard ratio 0.22, P=0.03). In conclusion, efficient cytoreduction followed by donor-lymphocyte infusion and subsequent interferon-α leading to limited acute graft-versus-host-disease represents a potentially curative option for patients with relapsed acute myeloid leukemia after allogeneic transplantation.

Achieving stringent CR is essential before reduced-intensity conditioning allogeneic hematopoietic cell transplantation in AML

Reduced-intensity conditioning (RIC) allogeneic hematopoietic cell transplantation (allo-HCT) can cure patients with AML in CR. However, relapse after RIC allo-HCT may indicate heterogeneity in the stringency of CR. Strict definition of CR requires no evidence of leukemia by both morphologic and flow cytometric criteria. We re-evaluated 85 AML patients receiving RIC allo-HCT in CR to test if a strict definition of CR had direct implications for the outcome. These patients had leukemia immunophenotype documented at diagnosis and analyzed at allo-HCT. Eight (9.4%) had persistent leukemia by flow cytometric criteria at allo-HCT. The patients with immunophenotypic persistent leukemia had a significantly increased relapse (hazard ratio (HR): 3.7; 95% confidence interval (CI): 1.3-10.3, P=0.01) and decreased survival (HR: 2.9; 95% CI: 1.3-6.4, P<0.01) versus 77 patients in CR by both morphology and flow cytometry. However, the pre-allo-HCT bone marrow (BM) blast count (that is, 0-4%) was not significantly associated with risks of relapse or survival. These data indicate the presence of leukemic cells, but not the BM blast count affects survival. A strict morphologic and clinical lab flow cytometric definition of CR predicts outcomes after RIC allo-HCT, and therefore is critical to achieve at transplantation.

Autologous Stem Cell Transplantation in elderly Acute Myeloid Leukemia

Treatment outcome in elderly Acute Myeloid Leukemia (AML) is still very disappointing. Although complete remission rate is around 50–60% the 2 years survival is only in the magnitude of 10–20%. This is mainly due to an overrepresentation of adverse prognostic factors present in elderly AML. As relapses emerge from residual disease present after chemotherapy, intensification of treatment could emerge as a rational strategy. Intensification of chemotherapy by increasing the dose of anthracyclines or addition of gemtuzumab ozogamycin (Mylotarg) to standard chemotherapy indeed has proved to be of advantage in elderly AML. In younger AML autologous peripheral blood stem cell transplantation (AuPBSCT) as post remission treatment in comparison to intensive consolidation chemotherapy has been investigated in a few randomized studies. AuPBSCT showed reduced relapse rates with low non-relapse mortality rates. In elderly AML intensification by AuPBSCT also have been performed although randomized studies are lacking. Nevertheless, in the previous years various reports have suggested the potential utility of AuHSCT in AML of the elderly with encouraging results, albeit mostly in highly selected patients. Acceptable toxicity and a relatively low rate of transplant-related mortality has been notified. However relapses occurred which, irrespective of age, still remains the major cause of treatment failure of AuHSCT in AML. In this review we summarize the experience of AuPBSCT in elderly AML.

Do different conditioning regimens really make a difference?

Over the past 15 years, the use of reduced-intensity/nonmyeloablative conditioning regimens before allogeneic hematopoietic stem cell transplantation has been increasing. Despite major disparities in the level of myeloablation, intensity of immunosuppression (including great diversity of in vivo T-cell depletion), and postgraft immunomodulation, the different approaches have contributed jointly to a modification of the stage of allogeneic stem cell transplantation: transplantation-related procedure mortality has been decreased dramatically, allowing allogeneic immunotherapy to be used in previously excluded populations, including elderly patients, young but clinically unsuitable patients, patients with lymphoid malignancies or solid tumors, and patients without an HLA-identical related or unrelated donor. Together, these diverse regimens have provided one of the biggest breakthroughs since the birth of allogeneic BM transplantation. However, consensus on how to reach the optimal goal of minimal transplantation-related mortality with maximum graft-versus-tumor effect is far from being reached, and further studies are needed to define optimal conditioning and immunomodulatory regimens that can be integrated to reach this goal. These developments, which will most likely vary according to different clinical situations, have to be compared continuously with advances achieved in traditional allogeneic transplantation and nontransplantation treatments. However, the lack of prospective comparative trials is and will continue to make this task challenging.

Acute myeloid leukemia in the elderly

SUMMARY Acute myeloid leukemia in older patients is of poor outcome, characterized by a specific biology of acute myeloid leukemia and factors related to the patient’s physical condition. Aggressive therapy results in improved survival and quality of life when compared with palliative care. However, not all patients are candidates for such therapy. Disease often demonstrates resistance related to poor-risk cytogenetics, and patients are often unable to tolerate intensive chemotherapy. For those patients, novel agents are being investigated. Understanding of the disease biology, as well as the prognostic factors associated with the host, allows the better estimation of which patients are likely to benefit from standard therapy and which require alternative approaches.

Donor CD3(+) lymphocyte infusion after reduced intensity conditioning allogeneic stem cell transplantation: single-center experience

Donor lymphocyte infusions (DLI) can induce remission in patients with hematologic malignancies who relapse after allogeneic stem cell transplantation. However, graft-vs-host disease (GVHD) remains a major complication of this strategy. We have used escalating doses of DLI for many years, and wanted to assess the risk factors for GVHD and transplant-related mortality as well as disease outcomes according to the reason for DLI. We analyzed 65 patients who received a total of 111 DLI for different reasons and at different intervals after transplantation. Median number of DLI was 2 (range, 1-4), median interval between transplantation and DLI was 9 months (range, 1-41 months) and median number of infused CD3(+) cells/kg recipient body weight was 2.5 × 10(7) (range, 1 × 10(6)-11.8 × 10(7)). Reasons for DLI were relapse or progression in 37 patients (57%), residual disease in 15 patients (23%), and persistence of mixed chimerism in 13 patients (20%). Seven patients (11%) developed acute GVHD grade II to IV and 5 patients (8%) developed extensive chronic GVHD. In univariate analysis, we could identify a transplantation-DLI interval ≤6 months, the dose of DLI (≥1 × 10(7)), and DLI number as predictive factors of GVHD. In multivariate analysis, these results were confirmed only for the transplantation-DLI interval (hazard ratio = 19.48; 2.23-170.34; p = 0.007). Our findings indicate that this form of adoptive immunotherapy is well tolerated and induces a low incidence of GVHD and transplant-related mortality, supporting further investigation as an upfront modality to enhance the graft-vs-tumor response in high-risk patients.

The European LeukemiaNet AML Working Party consensus statement on allogeneic HSCT for patients with AML in remission: an integrated-risk adapted approach

Allogeneic haematopoietic stem-cell transplantation (HSCT) is frequently applied as part of the treatment in patients with acute myeloid leukaemia (AML) in their first or subsequent remission. Allogeneic HSCT reduces relapse, but nonrelapse mortality and morbidity might counterbalance this beneficial effect. Here, we review recent studies reporting new disease-specific prognostic markers, in addition to allogeneic-HSCT-related risk factors, which can be assessed at specific time points during treatment. We propose risk assessment as a dynamic process during treatment, incorporating both disease-related and transplant-related factors for the decision to proceed either to allogeneic HSCT or to apply a nontransplant strategy. We suggest that allogeneic HSCT might be favoured if the projected disease-free survival is expected to improve by at least 10% based on an individual's risk assessment. The approach requires initial disease risk assessment, identifying a sibling or unrelated donor soon after diagnosis and the incorporation of time-dependent risk factors, all within the context of an integrated therapeutic management approach.

Intensive consolidation therapy compared with standard consolidation and maintenance therapy for adults with acute myeloid leukaemia aged between 46 and 60 years: final results of the randomized phase III study (AML 8B) of the European Organization for Research and Treatment of Cancer (EORTC) and the Gruppo Italiano Malattie Ematologiche Maligne dell'Adulto (GIMEMA) Leukemia Cooperative Groups

The most effective post-remission treatment to maintain complete remission (CR) in adults aged between 46 and 60 years with acute myeloid leukaemia (AML) is uncertain. Previously untreated patients with AML in CR after induction chemotherapy with daunorubicin and cytarabine were randomized between two intensive courses of consolidation therapy containing high-dose cytarabine, combined with amsacrine or daunorubicin and a standard consolidation and maintenance therapy containing standard dose cytarabine and daunorubicin. One hundred fifty-eight CR patients were assigned to the intensive group and 157 patients to the standard group. After a median follow-up of 7.5 years, the 4-year survival rate was 32 % in the intensive group versus 34 % in the standard group (P = 0.29). In the intensive group, the 4-year relapse incidence was lower than in the standard group: 55 and 75 %, respectively (P = 0.0003), whereas treatment-related mortality incidence was higher: 22 versus 3 % (P < 0.0001). Two intensive consolidation courses containing high-dose cytarabine as post-remission treatment in patients with AML aged between 46 and 60 years old did not translate in better long-term outcome despite a 20 % lower relapse incidence. Better supportive care and prevention of treatment-related complications may improve the overall survival after intensified post-remission therapy in this age group.

Early matched sibling hematopoietic cell transplantation for adult AML in first remission using an age-adapted strategy: long-term results of a prospective GOELAMS study

The LAM2001 phase 3 trial, involving 832 patients with acute myeloid leukemia (AML; median: 46 years) proposed HLA-identical sibling allograft HSCT for all patients with an identified donor. The trial compared reduced-intensity conditioning (RIC) for patients older than 50 years of age (N = 47) and myeloablative conditioning for younger patients (N = 117). BM HSCT was performed in the younger patients, while the older ones received a consolidation course, followed by peripheral blood allo-HSCT using RIC. The incidence of grade II-IV acute GVHD, was 51.9% (95% confidence interval [CI]: 42.1-61.8) and 11.3% (1.6-21.2) after myeloablative or RIC, respectively (P < .0001) and that of chronic GVHD 45.8% (95% CI: 34.8-56.7) and 41.7% (24.7-58.6; NS). Cumulative incidence of nonrelapse mortality at 108 months was 15.8% (95% CI: 9.8-23.2) for myeloablative, and 6.5% (0.2-16.2) for RIC (NS). CI of relapse at 108 months was 21.7% (95% CI: 13.9-28.6) and 28.6% (16.5-43.4; NS). Overall survival at 108 months was 63.4% (95% CI: 54.6-72.2) and 65.8% (52.2-72.2), respectively, after myeloablative or RIC (NS). RIC peripheral blood stem cell allo-HSCT is prospectively feasible for patients between the ages of 51 and 60 years without excess of relapse or nonrelapse mortality, and compares favorably with myeloablative marrow allo-HSCT proposed to younger patients. This study was registered at clinicaltrials.gov as no. NCT01015196.

The increase from 2.5 to 5 mg/kg of rabbit anti-thymocyte-globulin dose in reduced intensity conditioning reduces acute and chronic GVHD for patients with myeloid malignancies undergoing allo-SCT

We previously reported that reduced intensity conditioning (RIC) regimen with fludarabine, BU and 2.5 mg/kg of rabbit anti-thymocyte globulin (r-ATG) was effective but associated with a high rate of acute and chronic GVHD. Therefore, we increased the dose of r-ATG to 5 mg/kg. In this report, we analyzed 87 patients with AML or myelodysplastic syndrome (MDS) undergoing allo-SCT from an HLA-identical sibling donor from 2000 to 2010. RIC consisted of fludarabine, BU and r-ATG 2.5 mg/kg on 1 day (r-ATG1; n=53) or 2.5 mg/kg per day over 2 days (r-ATG2; n=22). Grade 2-4 acute GVHD incidence at day 100 was 30.2% and 8.8% in the r-ATG1 and r-ATG2 groups, respectively (P=0.038). Extensive chronic GVHD incidence was 60.4% and 12% in the r-ATG1 and r-ATG2 groups, respectively (P<0.001). The relapse incidences (RI) at 24 months were 18.9% and 28.5% in r-ATG1 and r-ATG2 groups, respectively (P=0.640). Overall and PFS were not different between the r-ATG1 and r-ATG2 groups. r-ATG dose at 5 mg/kg in the setting of RIC seems a good balance allowing GVHD prevention and antitumor effect with a remarkable reduction of GVHD incidence without an identical level of increased relapse rate.

Reduced-Intensity Conditioning Allogeneic Hematopoietic Cell Transplantation in Adults with Acute Myeloid Leukemia

Background

Acute myeloid leukemia (AML), whether de novo or arising from antecedent hematologic disorders in elderly patients, is less likely to be curable with standard chemotherapy regimens used for younger patients. Allogeneic hematopoietic cell transplantation (alloHCT) is currently the most efficient anti-leukemia treatment for AML and has shown a survival advantage in younger patients with intermediate- or poor-risk cytogenetics.

Methods

The authors review their experience as well as the published data regarding the role of reduced-intensity conditioning (RIC) alloHCT in adults with AML. MEDLINE/PubMed and EMBASE/Ovid were searched, as well as reference lists of relevant articles, conference proceedings, and ongoing trial databases.

Results

Elderly patients with AML have a poor survival for all cytogenetics subgroups (except for acute promyelocytic leukemia) and higher rates of transplant-related mortality with myeloablative alloHCT. RIC regimens have been shown to decrease procedure-related toxicity and have emerged as an attractive treatment modality in AML patients not suitable for myeloablative conditioning regimens. While prospective data comparing outcomes of AML patients undergoing RIC alloHCT vs conventional chemotherapy alone are not yet available, RIC alloHCT is a reasonable option for high-risk older patients and for younger AML patients with medical comorbidities who achieve a first or subsequent remission. The application of RIC for patients with refractory disease or untreated relapse as well as the use of alternative donors should be considered within the context of clinical trials.

Conclusions

RIC alloHCT is a safe and effective treatment modality in high-risk elderly AML patients and in younger AML patients with medical comorbidities.

Effect of conditioning regimen intensity on acute myeloid leukemia outcomes after umbilical cord blood transplantation

Reduced-intensity conditioning (RIC) umbilical cord blood (UCB) transplantation is increasingly used in hematopoietic stem cell transplantation (HCT) for older and medically unfit patients. Data on the efficacy of HCT after RIC relative to myeloablative conditioning (MAC) are limited. We compared the outcomes of acute myeloid leukemia (AML) patients >18 yrs who received UCB grafts after either RIC or MAC. One hundred nineteen adult patients with AML in complete remission (CR) underwent an UCB transplant after RIC (n =74, 62%) or MAC (n = 45, 38%) between January 2001 and December 2009. Conditioning was either reduced intensity and consisted of cyclophosphamide 50 mg/kg, fludarabine 200 mg/m(2), and total-body irradiation (TBI) 200 cGy or myelablative and consisted for cyclophosphamide 120 mg/kg, fludarabine 75 mg/m(2), and TBI 1200-1320 cGy. All patients received cyclosporine (day -3 to day +180) and mycophenolate mofetil (day -3 to day +45) post-HCT immunosuppression and hematopoietic growth factor. Use of RIC was reserved for patients >45 years (n = 66, 89%) or preexisting severe comorbidities (n = 8, 11%). The 2 groups were similar except for preceding myelodysplastic syndrome (RIC = 28% versus MAC = 4%, P < .01) and age that was dictated by the treatment protocols (median, RIC = 55 years versus MAC = 33years; P < .01). The incidence of neutrophil recovery at day +42 was higher with RIC (94% versus MAC = 82%, P < .1), whereas platelet recovery at the sixth month was similar (RIC = 68% versus MAC = 67%, P = .30). Incidence of grade II-IV acute graft-versus-host disease (aGVHD) (RIC = 47% versus MAC = 67%, P < .01) was decreased with similar incidence of chronic GVHD (cGVHD) (RIC = 30% versus MAC = 34%, P = .43). Median follow-up for survivors was 3.8 and 4.5 years for RIC and MAC, respectively (P = .4). Using RIC, 3-year leukemia-free survival (LFS) was decreased (31% versus MAC = 55%, P = .02) and 3-year relapse incidence was increased (43% versus MAC = 9%, P < .01). Two-year transplant-related mortality (TRM) was similar (RIC = 19% versus MAC = 27%; P = .55). In multivariate analysis, RIC recipients and those in CR2 with CR1 duration <1 year had higher risk of relapse and poorer LFS with no independent predictors of TRM. UCB with RIC extends the use of allogeneic HCT for older and frail patients without excessive TRM with greater benefit for patients in CR1 and CR2 with longer CR1.

Minimal residual disease testing to predict relapse following transplant for AML and high-grade myelodysplastic syndromes

Evaluation of: Lange T, Hubmann M, Burkhardt R et al. Monitoring of WT1 expression in PB and CD34(+) donor chimerism of BM predicts early relapse in AML and MDS patients after hematopoietic cell transplantation with reduced-intensity conditioning. Leukemia 25, 498-505 (2011). Early detection of relapse is critical for patients who have undergone hematopoietic stem cell transplantation (HSCT) for acute myeloid leukemia (AML) or high-grade myelodysplastic syndromes (MDS), since therapy can be initiated while disease burden remains low. As these neoplasms represent a heterogeneous group of malignancies with distinct underlying mutations, no single genetic marker exists that both defines AML/MDS and can be exploited for sensitive detection of neoplastic cells prior to overt hematologic relapse. Conversely, the Wilms' tumor gene (WT1) expression level is increased in blasts of most AML/MDS patients, and quantitative analysis of WT1 expression has been used to predict relapse following myeloablative HSCT. In this article, we review a recently published study evaluating the usefulness of multiple markers, including WT1 expression, for predicting relapse in AML/MDS patients following reduced-intensity conditioning nonmyeloablative HSCT.

Allogeneic immunotherapy to optimize the graft-versus-tumor effect: concepts and controversies

This article focuses on the recent evolution of novel conditioning regimens in combination with adoptive cellular therapy in the allogeneic transplant setting for hematologic malignancies. Building on data from animal models, the field of allogeneic transplantation is undergoing a paradigm shift toward immunosuppressive regimens with less toxicity that allow donor hematopoietic engraftment in order to provide a graft-versus-tumor effect as the primary goal of transplantation, rather than chemoablation. In addition, the strategies described in this article, including the use of T-cell subsets as adoptive therapy, will apply to a much broader pool of patients than traditional transplant approaches, thereby allowing more patients with life-limiting illnesses, previously deemed ineligible, to pursue therapy with curative intent.

Myeloablative reduced-toxicity i.v. busulfan-fludarabine and allogeneic hematopoietic stem cell transplant for patients with acute myeloid leukemia or myelodysplastic syndrome in the sixth through eighth decades of life

The optimal pretransplant regimen for acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) in patients ≥ 55 years of age remains to be determined. The myeloablative reduced-toxicity 4-day regimen i.v. busulfan (Bu) (130 mg/m(2)) and i.v. fludarabine (Flu) (40 mg/m(2)) is associated with low morbidity and mortality. We analyzed 79 patients ≥ 55 years of age (median, 58 years) with AML (n = 63) or MDS (n = 16) treated with i.v. Bu-Flu conditioning regimens between 2001 and 2009 (median follow-up, 24 months). The patients who received this regimen had a good performance status. The 2-year overall survival (OS) rates for patients in first complete remission (CR1), second CR (CR2), or refractory disease and for all patients at time of transplantation were 71%, 44%, 32%, and 46%, respectively; 2-year event-free survival (EFS) rates for patients in CR1, CR2, or refractory disease at time of transplantation and for all patients were 68%, 42%, 30%, and 44%, respectively. One-year transplant-related mortality (TRM) rates for patients who were in CR or who had active disease at the time of transplantation were 19% and 20%, respectively. Grade II-IV acute graft-versus-host (aGVHD) disease was diagnosed in 40% of the patients. Our results suggest that age alone should not be the primary reason for exclusion from receiving myeloablative reduced-toxicity conditioning with i.v. Bu-Flu preceding transplantation in patients with AML/MDS.

Radioimmunotherapy-based conditioning for hematopoietic cell transplantation in children with malignant and nonmalignant diseases

Targeted irradiation of the bone marrow with radiolabeled monoclonal antibodies (radioimmunotherapy) represents a novel therapeutic approach with both myeloablative and antileukemic potential. In an open-label, single-center pilot study, 30 pediatric and adolescent patients undergoing hematopoietic cell transplantation for malignant (n = 16) and nonmalignant (n = 14) disorders received treatment with a ⁹⁰Y-labeled anti-CD66 monoclonal antibody. Patients with a high risk of relapse (n = 7) received additional treatment with standard conditioning based on either total body irradiation or busulfan to intensify the antileukemic effect. In patients with comorbidities (n = 23), radioimmunotherapy was combined with a reduced-intensity conditioning regimen to reduce systemic toxicity. Preferential irradiation of the bone marrow was achieved in all patients. Nonrelapse mortality was 4 (13%) of 30 patients. In patients with malignant diseases, the probabilities of overall and disease-free survival at 2 years were 0.69 (95% confidence interval 0.37-0.87) and 0.46 (95% confidence interval 0.19-0.70), respectively. In patients with nonmalignant diseases, the probability of both overall and disease-free survival at 2 years was 0.94 (95% confidence interval 0.63-0.99). This pilot study demonstrates that radioimmunotherapy is effective in achieving myeloablation with low additional toxicity when used in combination with standard or reduced-intensity conditioning in young patients.

Modern Therapy of Acute Lymphoblastic Leukemia

Although acute lymphoblastic leukemia is curable in one third of adult patients, results vary greatly on account of different clinical, immunologic, and cytogenetic/genetic characteristics. These data, along with the kinetics of response to early treatment, help establish the individual risk class with considerable accuracy, and support risk-specific treatments that should warrant optimal results with as little as possible nonrelapse mortality. Modern first-line therapy consists of standard- and high-dose chemotherapy (increasingly inspired to pediatric principles), hematopoietic stem-cell transplantation, and new targeted therapy, all integrated with the analysis of prognostic factors and the study of subclinical residual disease for key therapeutic decisions. These changes are improving long-term outcome, which in ongoing studies is expected close to 50% or greater.

Challenges in treating older patients with acute myeloid leukemia

Whereas in younger patients diagnosed with acute myeloid leukemia (AML) treatment is straightforward and the goal is cure, the optimal treatment decision for older adults remains highly controversial. Physicians need to determine whether palliation, “something” beyond palliation, intensive therapy, or an investigational therapy is the most appropriate treatment option. This requires understanding of the biology and risk profile of the AML, clinical judgment in evaluating the functional status of the patient, communication skills in understanding the patient's wishes and social background, and medical expertise in available therapies. The physician has to accurately inform the patient about (a) the unique biological considerations of his leukemia and his prognosis; (b) the risks and benefits of all available treatment options; (c) novel therapeutic approaches and how the patient can get access to these treatments. Last but not least, he has to recommend a treatment. This paper tries to discuss each of these issues.

Reduced intensity conditioning prior to allogeneic stem cell transplantation in first complete remission is effective in patients with acute myeloid leukemia and an intermediate-risk karyotype

To evaluate the efficacy of reduced intensity conditioning (RIC) prior to allogeneic stem cell transplantation (alloSCT) in patients with acute myeloid leukemia (AML) in first complete remission (CR1), we retrospectively analyzed the outcome of 93 consecutive patients transplanted at our institution either following RIC (n = 37) or standard myeloablative conditioning (MAC) (n = 56) between 1999 and 2007. Projected overall survival (OS) or disease-free survival (DFS) for all patients at 1, 2, and 5 years was 78 or 70%, 65 or 57%, and 61 or 53% in the RIC group versus 73 or 70%, 68 or 62%, and 56 or 54% in the standard MAC group. In the subgroup of patients with an intermediate-risk karyotype projected OS at 1, 2, and 5 years was 86, 68, and 68% following RIC (n = 21) or 75, 69, and 66% following standard MAC (n = 36). Relapse or treatment-related mortality (TRM) was 15 or 17% (RIC group) and 26 or 14% (standard MAC group). Taken together, these data suggest that RIC-alloSCT may induce stable remissions in patients with AML transplanted in CR1. In particular, patients with an intermediate-risk karyotype ineligible to transplantation following standard MAC may benefit from RIC-alloSCT in CR1 at a low TRM.

What is the role of reduced-intensity transplantation in the treatment of older patients with AML?

Acute myelogenous leukemia (AML), either de novo or arising out of antecedent myelodysplasia, increases with age and is rarely curable by standard treatments used for younger patients. Recent clinical trials using reduced-intensity allogeneic transplantation regimens suggest that a proportion of patients with this disease can be cured, with results comparable to those achieved in younger patients undergoing fully ablative transplant. Although those patients who undergo transplant in a first remission often do well, the vast majority of older patients have not benefited because of the low successful remission achieved with standard therapy, the delay in initiating a donor search, and the lack of significant benefit from transplantation in patients who are not in remission. New approaches to induction, improvements in reduced-intensity regimens, and earlier donor identification will help expand the potential clinical benefit to a larger number of older patients with the disease.