Allogeneic stem cell transplantation after a fludarabine/busulfan-based reduced-intensity conditioning in patients with myelodysplastic syndrome or secondary acute myeloid leukemia

Current challenges in conditioning regimens for MDS transplantation

Myelodysplastic syndrome (MDS) is a very heterogeneous clonal disorder. Patients with "higher-risk" MDS, defined by specific recurrent genetic abnormalities, have a poor prognosis because of a high risk of progression to secondary acute myeloid leukemia with low chemosensitivity. Allogeneic hematopoietic stem cell transplantation remains the only treatment that offers durable disease control because the donor immune system allows graft-versus-MDS effects. In terms of preparation steps before transplantation, targeting the malignant clone by increasing the conditioning regimen intensity is still a matter of intense debate. MDS is mainly diagnosed in older patients, and high toxicity related to common myeloablative conditioning regimens has been reported. Efforts to include new drugs in the conditioning regimen to achieve the best malignant clone control without increasing toxicity have been made over the past 20 years. We summarized these retrospective and prospective studies and evaluated the limitations of the available evidence to delineate the ideal conditioning regimen.

Valutazione economica di treosulfan in pazienti sottoposti a trapianto allogenico di cellule staminali ematopoietiche

Objective:

To assess the cost-effectiveness and economic sustainability of treosulfan plus fludarabine compared with busulfan plus fludarabine as a conditioning treatment for malignant disease prior to allogeneic haematopoietic stem cell transplantation (alloHSCT) in adult patients in Italy.

Method:

The two theoretical cohorts of patients aged ≥ 60 years with acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS) were pooled and followed over time using a partitioned survival model with cycles of 28 days. Patients can transition between a post-HSCT recovery/remission state (Event-Free Survival state, EFS state), a relapsed/progressed disease state, and a death state. A lifetime horizon for cost-effectiveness analysis and a 5-years’ time horizon for budget impact analysis were used. The perspective of the Italian National Health Service was adopted. Utility values were obtained from published sources. Costs included: drug acquisition, HSCT procedure, management and treatment of adverse reactions, graft-versus-host disease (GvHD) and health states, end of life treatment. Discounting of 3% per year was applied for both costs and outcomes according to Italian guidelines. Sensitivity was tested through both one-way and probabilistic analyses.

Results:

Cost-effectiveness analysis showed that treosulfan is both more effective and less expensive compared with busulfan (+1.08 life-years, +0.95 quality-adjusted life-years per patient and –€ 41,388 per patient). On the side of economic sustainability, the introduction of treosulfan in the market could generate a cumulative decrement of the expense incurred by NHS of about –€ 212,063 over five years.

Conclusion:

Treosulfan could represent a cost-effective and sustainable treatment alternative from the perspective of the NHS.

Current status of pretransplant intensive chemotherapy or hypomethylating agents for myelodysplastic syndrome

Myelodysplastic syndrome is a heterogeneous disease with survival probabilities ranging from a few months to several years. Allogeneic hematopoietic cell transplantation (HCT) remains the only curative treatment. Although access (up to 75 years) and outcome of HCT have improved steadily in recent years, high relapse rates and, to a lower extent, treatment related mortalities are a persisting problem. Reduction of tumor burden before HCT has been shown to decrease relapse incidence and often overall survival (OS) in hematological malignancies but the role of pretransplant therapy in MDS remains controversial. We reviewed the role of pretransplant therapy on outcome in MDS patients. No prospective randomized trial addressed this issue so far. Retrospective studies have shown that pretransplant therapy reduces the risk of relapse, but does not improve survival. In addition, registry studies from diagnosis with standard protocols are proposed in order to exclude patient selection. With the availability of new, more effective and low-toxicity therapies, it may be possible to achieve a significant improvement of OS in the future.

Outcome of patients with relapsed or refractory acute myeloid leukemia treated with Mito-FLAG salvage chemotherapy

PURPOSE

Curative intended treatment is challenging in patients with relapsed or refractory acute myeloid leukemia (r/r AML) and associated with a dismal prognosis for long-term survival. Despite novel treatment options, the majority of patients are treated with chemotherapy-based regimens. Although widely used, little data exist on the combination of fludarabine, cytarabine, granulocyte colony stimulating factor (FLAG) and mitoxantrone as salvage strategy for r/r AML.

MATERIALS AND METHODS

Sixty-six patients receiving Mito-FLAG for r/r AML treated at a German tertiary care center between 2009 and 2019 were analyzed with regard to response rates, survival and safety profile.

RESULTS

Overall response rate was 75.8% with 56.1% of patients achieving complete remission (CR) and 19.7% partial remission (PR). After a median follow-up of 54 months, median overall survival (OS) was 13 months. Patients transitioned to allogeneic hematopoietic stem cell transplantation (alloHSCT) (75.8%) showed a significant improvement in OS with a median OS of 17 (95% CI 8.5-25.4) months vs 3 (95% CI 1.7-4.3) months (p < 0.001). 30- and 60-day mortality rates for all patients after the initial cycle of Mito-FLAG were 4.5% and 7.6%, respectively.

CONCLUSION

The Mito-FLAG salvage protocol represents an effective and feasible treatment regimen for r/r AML. Importantly, a high rate of transition to successful alloHSCT with the aim of long-term disease-free survival has been shown.

On Behalf of the SFGM-TC: Retrospective Comparison of Reduced and Higher Intensity Conditioning for High-Risk Myelodysplastic Syndrome Treated With Allogeneic Stem-Cell Transplantation

BACKGROUND

Allogeneic hematopoietic stem-cell transplantation (allo-HSCT) remains the best curative option for high-risk myelodysplastic syndrome . We retrospectively compared patient outcomes after allo-HSCT according to the intensity of the conditioning regimen.

PATIENTS AND METHODS

Three conditioning regimens were compared in 427 patients allografted for high-risk myelodysplastic syndrome: reduced-intensity conditioning (RIC), fludarabine (150-160 mg/m²) and busulfan (6.4 mg/kg); sequential FLAMSA-RIC, fludarabine, amsacrine, and aracytine followed by RIC; and myeloablative with reduced toxicity (RTC), fludarabine and busulfan (9.6 mg/kg or 12.8 mg/kg).

RESULTS

The patients in the 3 conditioning groups were different in regards to the number of treatment lines (P< .001), percentage of blasts in bone marrow (P< .001), and disease status at transplantation (P< .001). No significant differences in outcomes (overall survival, progression-free survival, nonrelapse mortality, relapse incidence, and graft versus host disease relapse-free survival) were observed between the 3 groups. Using propensity score analysis to overcome baseline imbalances, we compared 70 patients receiving FLAMSA-RIC to 260 patients receiving RIC, and compared 83 patients receiving RTC to 252 patients receiving RIC. The only factor influencing overall and progression-free survival was cytogenetic risk at transplantation. After the covariate adjustment using propensity score to reduce baseline imbalances, the only factor influencing overall and progression-free survival was still cytogenetic risk at transplantation.

CONCLUSION

Overall survival appears to be similar with the 3 conditioning regimens. The only factor influencing survival is cytogenetic risk at transplantation, suggesting that new promising drugs in the conditioning and/or early interventions after transplantation are needed to improve outcomes in these patients.

Impact of induction chemotherapy with intermediate-dosed cytarabine and subsequent allogeneic stem cell transplantation on the outcome of high-risk acute myeloid leukemia

Background

Acute myeloid leukemia (AML) with antecedent hematological disease (s-AML) and treatment-related AML (t-AML) predicts poor prognosis. Intensive treatment protocols of those high-risk patients should consider allogeneic stem cell transplantation (allo-HSCT) in first complete remission (CR). Despite allo-HSCT, relapse rate remains high. Induction chemotherapy with liposomal cytarabine and daunorubicin (CPX-351) has been approved for patients with AML with myeloid-related changes (AML-MRC) or t-AML based on improved survival and remission rates compared to standard 7 + 3 induction.

Patients and methods

110 patients with newly diagnosed s-AML or t-AML at a university hospital were analyzed retrospectively. Median age was 62 years (24–77 years). A total of 65 patients with s-AML after MDS (59%) and 23 patients (20.9%) with t-AML were included. Induction chemotherapy consisted of intermediate-dosed cytarabine (ID-AraC) in combination with idarubicin (patients up to 60 years) or mitoxantrone (patients over 60 years). In patients subsequently undergoing allo-HSCT, reduced conditioning regimens (RIC) were applied prior to transplantation in 47 of 62 patients (76%).

Results

Induction chemotherapy with ID-AraC resulted in an overall response rate of 83% including complete remission (CR/CRi) in 69 patients (63%) with a low rate of early death (2.7%). Most relevant non-hematologic toxicity consisted of infectious complications including sepsis with need of intensive care treatment in five patients (4.5%) and proven or probable invasive fungal disease in eight patients (7.2%). Relapse-free survival (RFS), event-free survival (EFS) and overall survival (OS) of the whole cohort were 19 months (0–167), 10 months (0–234) and 15 months (0–234), respectively (p < 0.0001). A significant improvement of OS was observed in patients who underwent allo-HSCT compared to those without subsequent allo-HSCT: 9 vs. 46 months, p < 0.0001. Rate of transplantation-related mortality (TRM) in the early phase post allo-HSCT was low (0.9% at day 30 and 1.8% at day 90, respectively). RIC conditioning results in OS rate of 60% after 60 months post allo-HSCT (median OS not reached).

Conclusion

S-AML and t-AML patients receiving induction chemotherapy with intermediate-dosed cytarabine showed satisfactory response rate and consolidation therapy with allo-HSCT after full or reduced-intensity conditioning further improved survival in these patients with similar outcome as reported for CPX-351.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-021-03733-0.

Extra-medullary recurrence of myeloid leukemia as myeloid sarcoma after allogeneic stem cell transplantation: impact of conditioning intensity

Myeloid sarcoma (MS) as a solid extra-medullary (EM) manifestation of acute myeloid leukemia (AML), myeloproliferative or myelodysplastic syndromes is a rare presentation of relapse after allogeneic hematopoietic stem cell transplantation (HSCT). The databases of the Departments of Hematology and Oncology of the University Hospitals of Jena and Rostock were screened for patients aged 18 years or older for onset of MS after HSCT for myeloid malignancies between 2002 and 2019. Nineteen patients with MS were identified, the majority of whom had received reduced-intensity conditioning (RIC). The median onset of MS was 425 days after HSCT and the median overall survival since MS was 234 days. Although MS is associated with a poor prognosis, three patients survived more than two years and one more than 11 years after MS onset. These results indicate that RIC protocols may be associated with a higher risk of EM relapse. Since EM relapse occurred in the presence of Graft-versus-host-disease, these observations also demonstrate the limitations of graft-versus-tumor effects after HSCT. In conclusion, occurrence of MS after HSCT is associated with a poor prognosis, as multimodal curative concepts including intensive chemotherapy and another HSCT are often not viable.

Yttrium-90-labeled anti-CD45 antibody followed by a reduced-intensity hematopoietic cell transplantation for patients with relapsed/refractory leukemia or myelodysplasia

Outcomes of patients with persistent high-risk leukemia or myelodysplasia prior to allogeneic hematopoietic cell transplantation are dismal. We therefore conducted a phase I trial evaluating the use of CD45-targeted radiotherapy preceding hematopoietic cell transplantation with the goal of improving outcomes for this high-risk scenario. Fifteen patients, median age 62 (range 37-76) years, were treated: ten with advanced acute myeloid leukemia, five with high-risk myelodysplastic syndrome. All patients had evidence of disease prior to treatment including nine with marrow blast counts ranging from 7-84% and six with minimal residual disease. Patients received escalating doses of yttrium-90-labeled anti-CD45 antibody followed by fludarabine and 2 Gy total body irradiation prior to human leukocyte antigen-matched, related or unrelated hematopoietic cell transplantation. Although a maximum dose of 30 Gy was delivered to the liver, no dose-limiting toxicity was observed. Therefore, the maximum-tolerated dose could not be estimated. Treatment led to complete remission in 13 patients (87%). All patients engrafted by day 28. Six patients relapsed, median of 59 (range 6-351) days, after transplantation. The 1-year estimate of relapse was 41%. Eight patients (53%) are surviving with median follow up of 1.8 (range 0.9-5.9) years. Estimated overall survival at one and two years was 66% and 46%, respectively, with progression-free survival estimated to be 46% at each time point. In conclusion, the combination of ⁹⁰Y-DOTA-BC8 with an allogeneic hematopoietic cell transplantation regimen was feasible and tolerable. This approach appears promising in this high-risk leukemia/myelodysplasia patient population with active disease. (Trial registered at clinicaltrials.gov identifier: NCT01300572.)

Graft-versus-MDS effect after unrelated cord blood transplantation: a retrospective analysis of 752 patients registered at the Japanese Data Center for Hematopoietic Cell Transplantation

Allogeneic hematopoietic stem cell transplantation is the sole curative therapy for myelodysplastic syndrome (MDS). However, there is concern regarding graft failure and relapse in patients who undergo cord blood transplantation (CBT). We conducted a retrospective study of the CBT outcomes in MDS patients using the Japanese Data Center for Hematopoietic Cell Transplantation database. Seven hundred fifty-two de novo MDS patients of ≥18 years of age (median, 58 years) undergoing their first CBT between 2001 and 2015 were examined. Two-thirds of the patients were male, and were RAEB. The cumulative incidences of neutrophil and platelet engraftment at day 100 were 77 and 59%, respectively. The 3-year overall survival (OS) was 41% and the median survival of the patients was 1.25 years. A multivariate analysis of pre-transplant variables showed that the age, gender, cytogenetic subgroups, number of RBC transfusions, HCT-CI and year of CBT significantly influenced the outcome. The cumulative incidence of acute graft-versus-host disease (aGVHD) and chronic GVHD (cGVHD) was 32 and 21%, respectively. A survival benefit was observed in patients who developed cGVHD, but not aGVHD. Our results suggest that CBT is an acceptable alternative graft and that a graft-versus-MDS effect can be expected, especially in patients who develop cGVHD.

Antithymocyte globulin before allogeneic stem cell transplantation for progressive myelodysplastic syndrome: a study from the French Society of Bone Marrow Transplantation and Cellular Therapy

We investigated the impact of rabbit antithymocyte globulins (ATG) on patient outcomes after allogeneic stem cell transplantation (allo-SCT) for progressive myelodysplastic syndrome (MDS). Of the 242 consecutive patients who underwent allo-SCT for progressive MDS between October 1999 and December 2009, 93 received ATG (ATG group) at the median dose of 5 mg/kg, whereas 149 patients did not (no-ATG group). Donors were sibling (n = 153) or HLA-matched unrelated (n = 89). Patients received blood (n = 90) or marrow (n = 152) grafts after either myeloablative (n = 109) or reduced-intensity (n = 133) conditioning. Three-year overall and event-free survival, nonrelapse mortality, relapse, and chronic graft-versus-host disease (GVHD) development were not significantly different between the 2 groups. In contrast, acute grade II to IV GVHD occurred more often in the no-ATG group (55% of the patients) than in the ATG group (27%, P < .0001). Similar results were observed with acute grade III to IV GVHD (28% and 14% in the no-ATG group and ATG group, respectively; P = .009). In multivariate analysis, after adjustment with propensity score, the absence of ATG was the strongest parameter associated with an increased risk of acute grade II to IV GVHD (hazard ratio, 2.13; 95% confidence interval, 1.35 to 3.37; P = .001]. ATG had no impact on overall and event-free survival or cumulative incidence of the relapse. In conclusion, the addition of ATG to allo-SCT conditioning did not increase the incidence of relapse of patients with progressive MDS. The incidence of acute GVHD was decreased without compromising outcomes.

Long-term outcomes of alemtuzumab-based reduced-intensity conditioned hematopoietic stem cell transplantation for myelodysplastic syndrome and acute myelogenous leukemia secondary to myelodysplastic syndrome

Allogeneic hematopoietic stem cell transplantation (HSCT) with reduced-intensity conditioning (RIC) offers a potential cure for patients with myelodysplastic syndrome (MDS) who are ineligible for standard-intensity regimens. Previously published data from our institution suggest excellent outcomes at 1 yr using a uniform fludarabine, busulfan, and alemtuzumab-based regimen. Here we report long-term follow-up of 192 patients with MDS and acute myelogenous leukemia (AML) secondary to MDS (MDS-AML) transplanted with this protocol, using sibling (n = 45) or matched unrelated (n = 147) donors. The median age of the cohort was 57 yr (range, 21 to 72 yr), and median follow-up was 4.5 yr (range, 0.1 to 10.6 yr). The 5-yr overall survival (OS), event-free survival, and nonrelapse mortality were 44%, 33%, and 26% respectively. The incidence of de novo chronic graft-versus-host disease (GVHD) was low at 19%, illustrating the efficacy of alemtuzumab for GVHD prophylaxis. Conversely, the 5-yr relapse rate was 51%. For younger patients (age <50 yr), the 5-yr OS and relapse rates were 58% and 39%, respectively. On multivariate analysis, advanced age predicted significantly worse outcomes, with patients age >60 yr having a 5-yr OS of 15% and relapse rate of 66%. Patients receiving preemptive donor lymphocyte infusions had an impressive 5-yr OS of 67%, suggesting that this protocol may lend itself to the incorporation of immunotherapeutic strategies. Overall, these data demonstrate good 5-yr OS for patients with MDS and MDS-AML undergoing alemtuzumab-based RIC-HSCT. The low rate of chronic GVHD is encouraging, and comparative studies with other RIC protocols are warranted.

Unrelated donor allogeneic hematopoietic cell transplantation is underused as a curative therapy in eligible patients from the United States

Allogeneic hematopoietic cell transplantation (alloHCT) is a curative therapy for hematologic disorders including acute lymphoblastic and myeloid leukemia, chronic lymphocytic and myeloid leukemia, Hodgkin's and non-Hodgkin lymphoma, multiple myeloma, and myelodysplastic syndrome. To determine the utilization of alloHCT from unrelated donors (URDs) in the United States, we calculated the number of patients diagnosed with hematologic disorders age 20 to 74 years based on 2004 to 2008 Surveillance, Epidemiology and End Results and 2007 US Census data, estimated the percentage of patients who would be eligible for URD alloHCT after discounting the mortality rate during induction therapy and the rate of severe comorbidities, and compared these with the actual 2007 alloHCTs facilitated by the National Marrow Donor Program. We found that the number of URD alloHCT as a percentage of the estimated potential transplantations ranged from 11% for multiple myeloma to 54% for chronic myeloid leukemia, with an average percentage of 26% for all the disorders considered. In an analysis stratified by age groups (20 to 44, 45 to 64, and 65 to 74 years), the utilization of URD alloHCT was higher in younger patients than in older patients for all disorders. Of acute lymphoblastic and myeloid leukemia patients, approximately 66% underwent URD alloHCT later in the course of their disease (in second or greater complete remission). URD alloHCT is likely underused for potentially curable hematologic disorders, particularly in older patients. Understanding the reasons for low use of alloHCT may lead to strategies to expand the use of this curative therapy for more patients with hematologic disorders.

Allogeneic hematopoietic cell transplantation in patients age 60-70 years with de novo high-risk myelodysplastic syndrome or secondary acute myelogenous leukemia: comparison with patients lacking donors who received azacitidine

Standard first-line therapy for older patients with high-risk myelodysplastic syndrome (MDS) includes hypomethylating agents, such as azacitidine (AZA). However, the only approach with curative potential remains allogeneic hematopoietic cell transplantation (HCT). To date, no direct comparison of both strategies has been reported. The outcomes of 2 well-balanced cohorts of patients with high-risk MDS defined by age (60-70 years), performance status (Eastern Cooperative Oncology Group score ≤2), and donor availability (yes/no) were compared, including 103 patients undergoing HCT and 75 patients without this option who received AZA. The estimated 2-year overall survival after the start of treatment was 39% (95% confidence interval, 30%-50%) for the patients undergoing HCT and 23% (95% confidence interval, 14%-40%) for the patients receiving AZA therapy. In a multivariate Cox regression analysis of all patients (n = 178), Eastern Cooperative Oncology Group score (0 versus 1 versus 2; hazard ratio [HR], 2.9/3.9; P <  .001), cytogenetics (good versus intermediate versus poor; HR, 1.2/1.7; P = .026), and treatment (HCT versus AZA; HR, 0.3; P = .007) were associated with overall survival. This retrospective cohort analysis suggests a survival advantage for allogeneic HCT compared with AZA therapy in medically fit patients with high-risk MDS age 60-70 years. Prospective controlled studies are warranted.

Optimizing management of myelodysplastic syndromes post-allogeneic transplantation

Allogeneic hematopoietic stem cell transplantation is still the only potentially curative treatment for patients with myelodysplastic syndromes. Improvements in donor selection, supportive care and the introduction of reduced-intensity conditioning have led to a decrease in early transplant mortality. However, relapse rates have not changed significantly in recent years. Furthermore, treatment options for patients relapsing after hematopoietic stem cell transplantation are limited and often short-lived. Thus, optimizing the post-transplant outcome by maintenance approaches or minimal residual disease-directed preemptive therapy is an important goal of current clinical research. Further strategies aiming at an improved prevention of graft-versus-host disease are currently under investigation.

Phase II prospective study of treosulfan-based reduced-intensity conditioning in allogeneic HSCT for hematological malignancies from 10/10 HLA-identical unrelated donor

Different RIC regimens were evaluated prior to allo-HSCT in different hematological malignancies. We conducted this prospective study in adult patients with various hematological malignancies in order to evaluate the toxicity and efficacy of treosulfan-based conditioning, followed by allo-HSCT from 10/10 HLA-identical unrelated donors. Conditioning included treosulfan 12 g/m(2)/day i.v. (day -6 to day -4), fludarabine 30 mg/m(2)/day i.v. (day -6 to day -2), and ATG 2.5 mg/kg/day (day -2 to day -1). PBSC were used as HSC source. We included 56 patients (29 AML, 9 MM, 8 MDS, 6 CLL, 3 ALL, and 1 CML) with a median age of 57 years (18-65.5). Fifty-four (96%) patients engrafted; the cumulative incidence of aGVHD grade ≥II at 3 months reached 31%. The cumulative incidence of cGVHD at 18 months was 34% limited and 8% extensive. The median overall survival (OS) was not reached with a 3-year probability of 52%. The cumulative incidence of relapse at 3 years was 25%, and the cumulative incidence of transplant-related mortality (TRM) at 12 and 24 months was 20% and 23%, respectively. Treosulfan appears to be a good alternative for conditioning of MUD transplant patients with promising results in terms of OS, relapse, and TRM.

Survival benefits from reduced-intensity conditioning in allogeneic stem cell transplantation for young lower-risk MDS patients without significant comorbidities

OBJECTIVE

The aim of this study was to determine the optimum conditioning intensity for allogeneic stem cell transplantation (SCT) in young (age ≤50), lower-risk (INT-1 by IPSS) Myelodysplastic syndrome (MDS) patients without significant comorbidities (hematopoietic cell transplantation-comorbidity index score ≤3).

METHODS

Transplant outcomes from 46 consecutive patients were retrospectively analyzed according to the conditioning intensity: reduced-intensity conditioning (RIC; n = 14), intensified RIC by adding low-dose total body irradiation (iRIC; n = 15), and myeloablative conditioning (MAC; n = 17).

RESULTS

After a median follow-up of 73.7 months, RIC had a better 4-yr overall survival (OS) (92.9%) compared with the iRIC (64.2%) or MAC (70.6%). Multivariate analysis showed that RIC was associated with improved OS compared with the MAC [relative risk (RR) of 0.08, P = 0.022] because of a lower transplant-related mortality (TRM) (RR, 0.08, P = 0.035). iRIC failed to show survival benefits over the MAC (RR of 0.77, P = 0.689) because of similarly high TRM (RR of 0.41, P = 0.480). Cumulative incidence of acute and chronic graft-versus-host disease (GVHD) after RIC was higher, but GVHD-specific survival was significantly better (RIC 100% vs. iRIC 45.7% vs. MAC, P = 0.018). Relapse rate was not different among the three groups, but in the RIC group, azacitidine was available and useful for inducing remission in two patients.

CONCLUSION

This study shows that RIC improved OS by directly lowering TRM and indirectly giving an additional chance for relapsed MDS in the era of hypomethylating treatment. RIC-SCT should be considered for relative healthy lower-risk MDS patients.

Hematopoietic stem cell transplantation for myelodysplastic syndrome: a review

Allogeneic hematopoietic stem cell transplantation (HSCT) continues to be the only curative option for myelodysplastic syndrome (MDS). Since the majority of the patients with this disease are often older and frail, treatment-related mortality and morbidity remain major obstacles to be overcome. Reduced-intensity conditioning and continued lines of investigation in the field of allogeneic transplantation are expected to ultimately improve the overall therapeutic approach to MDS. In this review we summarize current recommendations and controversies surrounding HSCT for MDS, as well as the use of novel therapeutics in the peri-transplant period.

Reduced-intensity allografting in patients with therapy-related myeloid neoplasms and active primary malignancies

Therapy-related myeloid neoplasms (t-MNs) are severe long-term consequences of cytotoxic treatments for a primary, often, malignant disorder. So far, the majority of patients eligible for transplantation have undergone myeloablative allo haematopoietic SCT (HSCT) as a potentially curative treatment, but it has been associated with high transplantation-related mortality (TRM) rates. In this retrospective study, we analysed the outcome of patients with t-MNs undergoing HSCT with reduced-intensity conditioning (RIC). Of 55 patients, seen at a single centre over a 10-year period, 17 underwent RIC HSCT with related or unrelated donors. The estimated overall survival was 53% at 1 year and 47% at 3 years, and disease-free survival was 47% at 1 year. At 1 year, the cumulative incidence of relapse and TRM were 24% and 30%, respectively. Of five patients with active primary neoplasms who underwent transplantation, two are alive beyond 1 year and show CR of both t-MNs and the primary malignancy. These data indicate that RIC HSCT is an encouraging approach for patients with t-MNs. The issue of primary malignancies not being in remission at the time of transplantation should be explored in further studies.

Single center retrospective analysis of BU-based conditioning regimens in allogeneic transplantation

We performed a single institution retrospective analysis of 114 patients treated with BU-based pretransplant conditioning regimens. Oral BU was administered to 76 patients (total dose 16 mg/kg or 8 mg/kg) and i.v. BU to 38 others (total dose 12.8 mg/kg or 6.4 mg/kg). Either CY (n=74) or fludarabine (n=40) was given in combination with BU. Median age was 35 years in the oral BU group and 48.5 years with i.v. BU (P<0.001). OS and PFS rates at 3-years post HSCT were not different in patients who received either i.v. or oral BU (OS: 41.3 vs 44.0% (P=0.981); PFS: 52.7 vs 54.7% (P=0.526), respectively). The i.v. BU, however, was associated with a significantly shorter time to engraftment (13.5 days vs 16 days, respectively; P<0.001). There were no significant differences in survival or 100-day mortality for patients who received either CY or fludarabine, in combination with BU. After adjustment for confounders, multivariate analysis showed that age of transplant (P=0.002), donor type (sibling or unrelated; P=0.003), GVHD (P<0.05) and route of administration (P=0.023) were significant risk factors for OS. The i.v. BU used in an older age group yielded equivalent survival compared with oral BU used in a younger population.

Azacitidine for treatment of patients with myelodysplastic syndromes (MDS): practical recommendations of the German MDS Study Group

Myelodysplastic syndromes (MDS) are a group of common bone marrow disorders characterized by ineffective hematopoiesis, peripheral cytopenias, and a substantial risk of progression to acute myeloid leukemia (AML). For many years, the main treatment option for MDS was best supportive care which alleviates symptoms, but has no effect on the natural course of the disease. Recently, demethylating agents have become available as a promising new treatment for patients with MDS. In two randomized clinical trials, the demethylating agent azacitidine has demonstrated a reduced risk of transformation to AML, improvement of peripheral blood values, an improved quality of life, and a definite survival advantage compared to conventional care regimens for patients with International Prognostic Scoring System score of intermediate-2 or high-risk MDS. This review aims to provide practical recommendations for the use of azacitidine and the management of its side effects in patients with MDS, assuring safe administration and best efficacy of treatment.

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.

Allogeneic hematopoietic stem-cell transplantation in patients with hematologic malignancies after dose-escalated treosulfan/fludarabine conditioning

PURPOSE

Treosulfan was introduced recently as a conditioning agent for allogeneic blood stem-cell transplantation. The favorable nonhematologic toxicity profile at 3 x 10 g/m(2) was the basis for dose escalation in this prospective, multicenter trial.

PATIENTS AND METHODS

Fifty-six patients with various hematologic malignancies who were not eligible for standard conditioning were treated with one of three doses: 10 g/m(2), 12 g/m(2), or 14 g/m(2) of intravenous treosulfan, which was administered on days -6 to -4 combined with fludarabine 30 mg/m(2) on days -6 to -2. Patients in complete remission (CR; 42%) or non-CR (58%) received grafts from matched related (47%) or matched unrelated (51%) donors; one patient had a mismatched related donor (2%).

RESULTS

No engraftment failure occurred. Overall, extramedullary toxicity and the nonrelapse mortality rate at 2 years (20%) were low and did not increase with dose. Cumulative incidence of relapse/progression reached 31%. The overall survival and progression-free survival rates were 64% and 49%, respectively, in the total study population. An inverse dose dependency of relapse incidence was indicated in the subgroup receiving transplantations from matched related donors (P = .0568).

CONCLUSION

Treosulfan-based conditioning was feasible at all three doses. The 3 x 14 g/m(2) dose was selected for additional studies, because it combines desired characteristics of low toxicity and a low relapse rate.

Diagnostic tools in the indications for allogeneic stem cell transplantation in myelodysplastic syndromes

The rates of allogeneic stem cell transplantation (SCT) to treat the myelodysplastic syndromes (MDS) is continually increasing. However, given the growing arsenal of therapeutic options in parallel to deeper insight into the heterogeneity of this disorder, determining the indications for SCT in MDS remains a difficult task. The International Prognostic Scoring System (IPSS) serves as a guideline for therapeutic decisions, but many aspects (eg, interpretation of rare cytogenetic abnormalities, combinations of chromosomal alterations and/or molecular markers, variant clinical courses within distinct biological subgroups) remain the subject of continuous investigation. In an effort to achieve a more well-differentiated risk categorization, attempts have been made to perform a more detailed cytogenetic categorization, and the use of various fluorescein in situ hybridization (FISH) techniques has improved the description of aberrations. Multicenter initiatives have standardized multiparameter flow cytometry techniques for diagnosis of MDS. In advanced MDS, screening for molecular mutations can identify cases with a high transformation risk. Finally, the new World Health Organization classification system provides a more homogenous morphological categorization of MDS compared with the former French-American-British system. Consequently, in the near future, risk stratification in MDS might incorporate additional diagnostic tools and categorization systems aimed at improving the timing and indication for SCT in this complex disorder.

Allogeneic hematopoietic cell transplantation after conditioning with 131I-anti-CD45 antibody plus fludarabine and low-dose total body irradiation for elderly patients with advanced acute myeloid leukemia or high-risk myelodysplastic syndrome

We conducted a study to estimate the maximum tolerated dose (MTD) of (131)I-anti-CD45 antibody (Ab; BC8) that can be combined with a standard reduced-intensity conditioning regimen before allogeneic hematopoietic cell transplantation. Fifty-eight patients older than 50 years with advanced acute myeloid leukemia (AML) or high-risk myelodysplastic syndrome (MDS) were treated with (131)I-BC8 Ab and fludarabine plus 2 Gy total body irradiation. Eighty-six percent of patients had AML or MDS with greater than 5% marrow blasts at the time of transplantation. Treatment produced a complete remission in all patients, and all had 100% donor-derived CD3(+) and CD33(+) cells in the blood by day 28 after the transplantation. The MTD of (131)I-BC8 Ab delivered to liver was estimated to be 24 Gy. Seven patients (12%) died of nonrelapse causes by day 100. The estimated probability of recurrent malignancy at 1 year is 40%, and the 1-year survival estimate is 41%. These results show that CD45-targeted radiotherapy can be safely combined with a reduced-intensity conditioning regimen to yield encouraging overall survival for older, high-risk patients with AML or MDS. This study was registered at www.clinicaltrials.gov as #NCT00008177.

Automated detection of residual cells after sex-mismatched stem-cell transplantation - evidence for presence of disease-marker negative residual cells

BACKGROUND

A new chimerism analysis based on automated interphase fluorescence in situ hybridization (FISH) evaluation was established to detect residual cells after allogene sex-mismatched bone marrow or blood stem-cell transplantation.Cells of 58 patients were characterized as disease-associated due to presence of a bcr/abl-gene-fusion or a trisomy 8 and/or a simultaneous hybridization of gonosome-specific centromeric probes. The automatic slide scanning platform Metafer with its module MetaCyte was used to analyse 3,000 cells per sample.

RESULTS

Overall 454 assays of 58 patients were analyzed. 13 of 58 patients showed residual recipient cells at one stage of more than 4% and 12 of 58 showed residual recipient cells less than 4%, respectively. As to be expected, patients of the latter group were associated with a higher survival rate (48 vs. 34 month). In only two of seven patients with disease-marker positive residual cells between 0.1-1.3% a relapse was observed. Besides, disease-marker negative residual cells were found in two patients without relapse at a rate of 2.8% and 3.3%, respectively.

CONCLUSION

The definite origin and meaning of disease-marker negative residual cells is still unclear. Overall, with the presented automatic chimerism analysis of interphase FISH slides, a sensitive method for detection of disease-marker positive residual cells is on hand.

The role of cytotoxic therapy with hematopoietic stem cell transplantation in the therapy of myelodysplastic syndromes: an evidence-based review

Clinical research examining the role of hematopoietic stem cell transplantation (SCT) in the therapy of myelodysplastic syndromes (MDS) in adults is presented and critically evaluated in this systematic evidence-based review. Specific criteria were used for searching the published literature and for grading the quality and strength of the evidence and the strength of the treatment recommendations. Treatment recommendations based on the evidence are presented in Table 3, and were reached unanimously by a panel of MDS experts. The identified priority areas of needed future research in MDS include: (1) the benefit of using alternative donor sources (eg, cord blood; haploidentical family donors) for patients without matched sibling or unrelated donors; (2) the role and appropriate timing of allogeneic SCT in combination with hypomethylating and immunomodulatory treatment regimens; (3) randomized trials comparing the safety and efficacy of various novel agents for treating MDS; and (4) the influence of the various MDS treatment modalities on patient-reported quality-of-life outcomes.

Myeloablative radioimmunotherapy in conditioning prior to haematological stem cell transplantation: closing the gap between benefit and toxicity?

High-dose radio-/chemotherapy in the context of autologous and allogeneic haematopoietic stem cell transplantation is a double-edged sword. The requirement for dose intensification is linked to an increase in toxicity to noninvolved organs. Particularly for older patients and patients with comorbidities, efficient but toxicity-reduced schemes are needed. Myeloablative radioimmunotherapy is a targeted, internal radiotherapy that uses radiolabelled monoclonal antibodies (mAb) with affinity to the bone marrow. It involves the administration of high radiation doses (up to 30 Gy) to the bone marrow and spleen but without exposing radiosensitive organs to doses higher than 1-7 Gy. Added to conventional or intensity-reduced conditioning, myeloablative radioimmunotherapy may achieve a pronounced antileukaemic effect with tolerable toxicities. A rational and individual design of the ideal nuclide-antibody combination optimizes therapy. The anti-CD33, anti-CD45 and anti-CD66 mAbs appear to be ideal tracers so far. The beta-emitter (90)Y is coupled by DTPA and is the best nuclide for myeloablation. Approval trials for DTPA anti-CD66 mAb are underway in Europe, and in the near future these therapies may become applicable in practice. This review gives an overview of current myeloablative conditioning radioimmunotherapy. We discuss the selection of the optimal radioimmunoconjugate and discuss how radioimmunotherapy might be optimized in the future by individualization of therapy protocols. We also highlight the potential advantages of combination therapies.

Red blood cell transfusion dependence and outcome after allogeneic peripheral blood stem cell transplantation in patients with de novo myelodysplastic syndrome (MDS)

The prognosis of patients with de novo myelodysplastic syndrome (MDS) who are red blood cell transfusion-dependent (TD) and receive supportive care is inferior to that of patients who do not require transfusions. Whether TD also affects outcome after allogeneic transplantation is unknown. Consequently, in 172 de novo MDS patients (median age, 51 years), we analyzed the impact of TD on outcome after high-dose conditioning and allogeneic peripheral blood stem cell transplantation (PBSCT). With a median follow-up of 37 months, the probability of 3-year overall survival (OS) did not differ significantly between patients who were TD and those who were not TD before PBSCT (P=.1); however, transfusion burden, as reflected by ferritin levels, was correlated with a greater probability of severe acute graft-versus-host disease (aGVHD; P=.03) and a higher comorbidity index (P=.01), and OS was inferior in those patients with a ferritin level>1000 microg/L before PBSCT (P=.03). In multivariate analysis, only marrow myeloblast count (P=.01) and comorbidity index (P=.001) had a significant impact on OS. Our data do not identify TD as an independent negative prognostic factor for outcome after allogeneic PBSCT' however, iron overload (presumably transfusion-related) may contribute to poor transplantation success by adding to the overall comorbidities. Whether clinical intervention in the form of iron chelation can improve the outcome of allogeneic PBSCT in TD patients with MDS remains to be determined.

Allogeneic stem cell transplantation in acute myeloid leukemia: establishment of indications on the basis of individual risk stratification

INTRODUCTION

Acute myeloid leukemia (AML) is a heterogeneous disorder with subtypes that differ considerably in morphology and in their underlying chromosomal and molecular aberrations, which, in turn, determine their prognosis. The establishment of the indications for allogeneic stem cell transplantation (SCT) therefore requires individualized risk stratification based on a combination of multiple diagnostic methods, including cytogenetic and molecular genetic studies, and immunophenotyping, as well as the sensitivity of the disease to chemotherapy.

METHODS

This article surveys the current strategies for establishing the indications for SCT in AML on the basis of a selective review of the relevant literature in the Medline database.

RESULTS

In patients with a high risk constellation-e.g., chromosome 7 anomalies, complex aberrations, or FLT3-length mutations-there is an indication for SCT in first remission. The balanced translocations t(15;17) and t(8;21), and the inversion inv(16) are prognostically favorable and are thus not considered an indication for SCT in first remission. The establishment of indications for stem cell transplantation also depends on the residual leukemic cell burden (minimal residual disease, MRD) as determined by the quantitative polymerase chain reaction or by flow cytometry, as well as an insufficient response to induction chemotherapy. Reduced-dose conditioning, a new technique that lessens acute toxicity, has been found to be associated with a 30% to over 50% two-year survival rate when used in the treatment of chemotherapeutically unresponsive or relapsing AML.

DISCUSSION

The indications for allogeneic SCT in AML should be further refined by more investigation in large studies.

Transplantation in remission improves the disease-free survival of patients with advanced myelodysplastic syndromes treated with myeloablative T cell-depleted stem cell transplants from HLA-identical siblings

From 1985 to 2004, 49 patients with advanced myelodysplastic syndromes (MDS) (> or =5% blasts) or acute myeloid leukemia (AML) transformed from MDS underwent T cell depleted bone marrow or peripheral blood hematopoietic stem cell transplantation (HSCT) from HLA-identical siblings following conditioning with a myeloablative regimen that included total body irradiation (44 patients) or busulfan (5 patients). Thirty-six patients received chemotherapy (3 low dose and 33 induction doses) before conditioning, and 13 patients did not receive any chemotherapy. Prior to transplantation, 22 of the 36 treated patients were in hematologic remission; 4 were in a second refractory cytopenia phase (26 responders); 8 had failed to achieve remission; and 2 of the responders had progression or relapse of their MDS (10 failures). No post-transplantation pharmacologic prophylaxis for graft-versus-host disease (GVHD) was given. The median age was 48 yrs (range 13-61). Forty-five of the 49 patients engrafted; 2 had primary graft failure; and 2 died before engraftment. Only 3 patients developed acute GVHD (aGVHD) (grades I and III) and 1 chronic GVHD (cGVHD). At 3 yrs post-transplantation, the overall survival (OS) was 54% in the responders; 31% in the untreated group; and 0% in the failure group (P=.0004). The disease free survival (DFS) was 50%, 15% and 0% in each group respectively (P=.0008). In multivariate analysis, disease status before cytoreduction remained highly correlated with DFS (P<.001). The cumulative incidence (CI) of relapse at 2-yrs post-transplantation for the responders was 23%; for the untreated group was 38%; and for the failures was 50%. The CI of non-relapse mortality at 2-yrs post-transplantation, for the responders was 23%; for the untreated group was 38%; and for the failures was 40%. All survivors achieved a Karnofsky Performance Status (KPS) of > or =90. These results indicate that patients with advanced MDS who achieve and remain in remission or a second refractory cytopenia phase with chemotherapy before conditioning can achieve successful long-term remissions following a myeloablative T cell depleted allogeneic HSCT.

Reduced-intensity conditioning followed by allogeneic hematopoietic cell transplantation for adult patients with myelodysplastic syndrome and myeloproliferative disorders

Allogeneic hematopoietic cell transplantation (HCT) is the only curative strategy for patients with myelodysplastic syndrome (MDS) and myeloproliferative disorders (MPD). We report the results of 148 patients (median age = 59 years old) with de novo MDS (n = 40), acute myelogenous leukemia (AML) after antecedent MDS/MPD (n = 49), treatment-related MDS (t-MDS) (n = 25), MPD (n = 27), and chronic myelomonocytic leukemia (CMML) (n = 7) who underwent allogeneic HCT using a conditioning regimen of low-dose total body irradiation (TBI) alone (200 cGy) on day 0 (n = 5) or with the addition of fludarabine (Flu) 30 mg/m(2)/day on days -4 to -2 (n = 143). Postgrafting immunosuppression consisted of cyclosporine and mycophenolate mofetil (MMF). Seventy-five patients (51%) received an allograft from a matched related donor (MRD), and 73 patients (49%) were recipients of unrelated donor (URD) grafts. There was no significant difference in the incidence of acute (gr II-IV) and chronic extensive graft-versus-host disease (aGVHD, cGVHD) between the recipients of related and unrelated donor grafts. By day +28, 75% of patients demonstrated mixed T cell chimerism. Graft rejection was seen in 15% of patients. With a median follow-up of 47 (range: 6-89) months, the 3-year relapse-free survival (RFS) and overall survival (OS) are both 27% for all patients, with a relapse incidence of 41%. The 3-year RFS for the patients with de novo MDS, AML after antecedent MDS/MPD, t-MDS, MPD, and CMML were 22%, 20%, 29%, 37%, and 43%, respectively, and the 3-year OS was 20%, 23%, 27%, 43%, and 43%, respectively. The 3-year nonrelapse mortality (NRM) was 32%. Factors associated with a lower risk of relapse were the development of extensive cGVHD and having a low risk or intermediate-1 risk International Prognostic Score for the de novo MDS patients. Nonmyeloablative HCT confers remissions in patients who otherwise were not eligible for conventional HCT but for whom relapse is the leading cause of treatment failure.

Epigenetic Modulation and Other Options to Improve Outcome of Stem Cell Transplantation in MDS

Allogeneic stem cell transplantation can cure patients with myelodysplastic syndromes. However, more than 50% of the patients who underwent allogeneic stem cell transplantation have failed to benefit from this treatment approach either due to treatment-related mortality or to relapse. The introduction of toxicity or dose-reduced conditioning has significantly reduced the treatment-related mortality but did not affect the risk of relapse. New effective drugs, such as hypomethylating agents, histone-deacetylase inhibitors or lenalidomide, can be used alone or in combination to improve the pretransplant remission status before allogeneic stem cell transplantation or after transplantation to prevent relapse as maintenance or consolidation therapy. This review will focus on these new possibilities and give some perspectives as to how the results of allogeneic stem cell transplantation can be further improved

Hematopoietic cell transplantation: progress and obstacles

The use of hematopoietic cell transplantation has expanded and evolved substantially in the last decade. New stem cell sources and stem cell mobilizing agents have been introduced in clinical practice. The incidence of life-threatening complications following autologous stem cell transplant procedures has decreased dramatically. Understanding the immune mediated effect of allogeneic stem cell transplantation has resulted in the development of reduced intensity and non-myeloablative conditioning regimens, allowing transplantation of elderly patients. Long-term complications are starting to emerge, and will gain in importance in the near future.

Comorbidity and disease status based risk stratification of outcomes among patients with acute myeloid leukemia or myelodysplasia receiving allogeneic hematopoietic cell transplantation

PURPOSE

Retrospective studies have shown similar survival among patients with acute myeloid leukemia (AML) and myelodysplasia (MDS) after nonmyeloablative compared with myeloablative conditioning. Refined risk stratification is required to design prospective trials.

PATIENTS AND METHODS

We stratified outcomes among patients with AML (n = 391) or MDS (n = 186) who received either nonmyeloablative (n = 125) or myeloablative (n = 452) allogeneic hematopoietic cell transplantation (HCT) based on comorbidities, as assessed by a HCT-specific comorbidity index (HCT-CI), as well as disease status. Patients receiving nonmyeloablative conditioning were older, more frequently pretreated, more often received unrelated grafts, and more often had HCT-CI scores of 3 compared with patients who received myeloablative conditioning.

RESULTS

Patients with HCT-CI scores of 0 to 2 and either low or high disease risks had probabilities of overall survival at 2 years of 70% and 57% after nonmyeloablative conditioning compared with 78% and 50% after myeloablative conditioning, respectively. Patients with HCT-CI scores of 3 and either low or high disease risks had probabilities of overall survival of 41% and 29% with nonmyeloablative conditioning compared with 45% and 24% with myeloablative regimens, respectively. After adjusting for pretransplantation differences, stratified outcomes were not significantly different among patients receiving nonmyeloablative compared with myeloablative conditioning, with the exception of lessened nonrelapse mortality (hazard ratio, 0.50; P = .05) in the highest risk group.

CONCLUSION

Patients with low comorbidity scores could be candidates for prospective randomized trials comparing nonmyeloablative and myeloablative conditioning regardless of disease status. Additional data are required for patients with low-risk diseases and high comorbidity scores. Novel antitumor agents combined with nonmyeloablative HCT should be explored among patients with high comorbidity scores and advanced disease.