Haploidentical Transplantation for Older Patients with Acute Myeloid Leukemia and Myelodysplastic Syndrome

Allogeneic stem cell transplantation with HLA-matched donors is increasingly used for older patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). It remains unclear if haploidentical stem cell transplantation (haploSCT) is a suitable option for older patients with this disease. We analyzed 43 patients with AML/MDS (median age, 61 years) who underwent a haploSCT at our institution. All patients received a fludarabine-melphalan–based reduced-intensity conditioning regimen and post-transplant cyclophosphamide-based graft-versus-host disease (GVHD) prophylaxis. Except for 1 patient who had early death, the remaining 42 patients (98%) engrafted donor cells. The cumulative incidences of grades II to IV and III to IV acute GVHD at 6 months were 35% and 5%, respectively, and chronic GVHD at 2 years was 9%. After a median follow-up of 19 months, 2-year overall survival, progression-free survival (PFS), and relapse incidence were 42%, 42%, and 24%, respectively. Best PFS (74% at 2 years) was seen in patients with intermediate-/good-risk cytogenetics, in first or second remission (hazard ratio, .4; P?=?.05), and with a younger donor (≤40 years; hazard ratio, .2; P?=?.01). In conclusion, these data suggest that haploidentical transplantation is safe and effective for older AML/MDS patients. Disease status, cytogenetics, and younger donor age are predictors for improved survival in older patients receiving a haploidentical transplant.     

CC-486 Maintenance after Stem Cell Transplantation in Patients with Acute Myeloid Leukemia or Myelodysplastic Syndromes

Relapse is the main cause of treatment failure after allogeneic stem cell transplant (alloSCT) in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). Injectable azacitidine can improve post-transplant outcomes but presents challenges with exposure and compliance. Oral CC-486 allows extended dosing to prolong azacitidine activity. We investigated use of CC-486 maintenance therapy after alloSCT.Adults with MDS or AML in morphologic complete remission at CC-486 initiation (42 to 84 days after alloSCT) were included. Patients received 1 of 4 CC-486 dosing schedules per 28-day cycle for up to 12 cycles. Endpoints included safety, pharmacokinetics, graft-versus-host disease (GVHD) incidence, relapse/progression rate, and survival.Of 30 patients, 7 received CC-486 once daily for 7 days per cycle (200 mg, n?=?3; 300 mg, n?=?4) and 23 for 14 days per cycle (150 mg, n?=?4; 200 mg, n?=?19 [expansion cohort]). Grades 3 to 4 adverse events were infrequent and occurred with similar frequency across regimens. Standard concomitant medications did not alter CC-486 pharmacokinetic parameters. Three patients (10%) experienced grade III acute GVHD and 9 experienced chronic GVHD. Of 28 evaluable patients, 6 (21%) relapsed or had progressive disease: 3 of 7 patients (43%) who had received 7-day dosing and 3 of 23 (13%) who had received 14-day dosing. Transplant-related mortality was 3%. At 19 months of follow-up, median overall survival was not reached. Estimated 1-year survival rates were 86% and 81% in the 7-day and 14-day dosing cohorts, respectively.CC-486 maintenance was generally well tolerated, with low rates of relapse, disease progression, and GVHD. CC-486 maintenance may permit epigenetic manipulation of the alloreactive response postallograft. Findings require confirmation in randomized trials. (ClinicalTrials.gov NCT01835587.)     

Treosulfan,Fludarabine, and Low-Dose Total Body Irradiation for Children and Young Adults with Acute Myeloid Leukemia or Myelodysplastic Syndrome Undergoing Allogeneic Hematopoietic Cell Transplantation: Prospective Phase II Trial of the Pediatric Blood and Marrow Transplant Consortium

This multicenter study evaluated a treosulfan-based regimen in children and young adults with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) undergoing allogeneic hematopoietic cell transplant (HCT). Forty patients with median age 11 years (range, 1 to 19) underwent allogeneic HCT for AML in first (n?=?18), second (n?=?11), and third or greater remission (n?=?3) or MDS (n?=?8) using bone marrow (n?=?25), peripheral blood stem cells (n?=?5), or cord blood (n?=?9). The regimen consisted of body surface area (BSA)-based treosulfan 10?g/m²/day (BSA?≤?.5?m²), 12?g/m²/day (BSA?>?.5 to 1.0?m²), or 14?g/m²/day (BSA?>?1.0?m²) on days ?6 to ?4; fludarabine 30?mg/m²/day on days ?6 to ?2; and a single fraction of 200 cGy total body irradiation on day ?1. Graft-versus-host disease (GVHD) prophylaxis included tacrolimus and methotrexate for marrow and peripheral blood stem cell and cyclosporine/mycophenolate mofetil for cord blood. One-year overall survival, disease-free survival, and nonrelapse mortality were 80%, 73%, and 3%, respectively. One-year relapse was 38% for AML and 13% for MDS. No serious organ toxicities were observed. All 37 assessable patients engrafted. Cumulative incidences of grades II to IV acute GVHD and chronic GVHD were 22% and 40%, respectively. BSA-based treosulfan dosing resulted in predictable area under the curve and maximum concentration, which is required for dosing without measuring individual pharmacokinetic parameters. Observed differences in pharmacokinetics did not impact disease control or regimen toxicity. This BSA-based treosulfan regimen resulted in excellent engraftment and disease-free survival and minimal toxicity and transplant-related mortality (3%) in children and young adults with AML and MDS.     

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.     

Outcome of Allogeneic Stem Cell Transplantation for Patients Transformed to Myelodysplastic Syndrome or Leukemia from Severe Aplastic Anemia: A Report from the MDS Subcommittee of the Chronic Malignancies Working Party and the Severe Aplastic Anemia Working Party of the European Group for Blood and Marrow Transplantation

One hundred and forty patients who had undergone hematopoietic stem cell transplantation (HSCT) for myelodysplastic syndrome (MDS) or acute myelogenous leukemia (AML) transformation after treatment of severe aplastic anemia (SAA) were identified in the European Group for Blood and Marrow Transplantation (EBMT) database. The median age at HSCT was 29 years (range, 1 to 66 years). The transplant donor was related in 49% cases and unrelated in 51% cases. The 5-year probability of relapse was 17%, and that of nonrelapse mortality was 41%. The 5-year overall survival was 45% ± 9%, better for patients untreated and patients in remission compared with patients with refractory disease. Our data indicate that allogeneic HSCT leads to prolonged survival in close to one-half of the patients transforming to MDS or AML from SAA.     

Intravenous Busulfan Compared with Treosulfan-Based Conditioning for Allogeneic Stem Cell Transplantation in Acute Myeloid Leukemia: A Study on Behalf of the Acute Leukemia Working Party of European Society for Blood and Marrow Transplantation

Dose intensity of the conditioning regimen has significant impact on the outcomes after stem cell transplantation (SCT) for acute myeloid leukemia. Most studies have shown more relapse, less nonrelapse mortality (NRM), and similar overall survival after reduced-intensity and myeloablative conditioning. There are limited data on the dose equivalence and expected outcomes of treosulfan-based compared with busulfan-based conditioning. We compared SCT outcomes after fludarabine with either intravenous busulfan at a myeloablative dose (FB4, 12.8?mg/kg, n?=?1265) or a reduced dose (FB2, 6.4?mg/kg, n?=?1456) or treosulfan at 42 g/m² (FT14, n?=?403) or 36 g/m² (FT12, n?=?168). Median patient age was 48, 60, 57, and 60 years in the FB4, FB2, FT14, and FT12 groups, respectively (P?<?.0001). Two-year overall survival was 58%, 53%, 53%, and 51%, respectively (P?=?.25). Multivariate analysis identified advanced age, advanced disease status, and secondary leukemia to be associated with worse survival. Relapse rate was 30%, 35%, 34%, and 40%, respectively. Relapse was more common after FB2, advanced age and disease status, secondary leukemia, and sibling donors. NRM was 17%, 18%, 21%, and 16%, respectively. NRM was least common after FT12 and more common with advanced age and disease status and unrelated donors. Treosulfan-based regimens were associated with lower rates of graft-versus-host disease. There was no difference in any outcome among patients in first complete remission at transplantation. However, there was better survival with treosulfan-based conditioning in advanced leukemia. In conclusion, survival is determined mostly by disease biology and is similar after various regimens. Treosulfan-based conditioning is more similar to myeloablative than to reduced-intensity conditioning but can be administered safely in older patients, with lower rates of graft-versus-host disease and possibly better outcomes in patients with active leukemia.     

The Art of Transplantation: Conditioning Intensity for Allogeneic Hematopoietic Stem Cell Transplantation

The search for the optimal conditioning regimen before allogeneic hematopoietic stem cell transplantation (HCT) for acute myelogenous leukemia (AML) and myelodysplastic syndromes (MDS) has been ongoing for decades. In this issue, Solh et al present an original analysis evaluating the impact of conditioning intensity on different disease risk index (DRI) groups of patients with AML and MDS. An impressive difference was observed in outcomes between reduced-intensity conditioning and myeloablative conditioning (MAC) regimens in the low/intermediate-risk disease groups, supporting the use of MAC in this population. Further prospective trials in this population are encouraged.     

Hematopoietic Stem Cell Transplantation in Children and Young Adults with Secondary Myelodysplastic Syndrome and Acute Myelogenous Leukemia after Aplastic Anemia

Secondary myelodysplastic syndrome and acute myelogenous leukemia (sMDS/sAML) are the most serious secondary events occurring after immunosuppressive therapy in patients with aplastic anemia. Here we evaluate the outcome of hematopoietic stem cell transplantation (HSCT) in 17 children and young adults with sMDS/sAML after childhood aplastic anemia. The median interval between the diagnosis of aplastic anemia and the development of sMDS/sAML was 2.9 years (range, 1.2 to 13.0 years). At a median age of 13.1 years (range, 4.4 to 26.7 years), patients underwent HSCT with bone marrow (n = 6) or peripheral blood stem cell (n = 11) grafts from HLA-matched sibling donors (n = 2), mismatched family donors (n = 2), or unrelated donors (n = 13). Monosomy 7 was detected in 13 patients. The preparative regimen consisted of busulfan, cyclophosphamide, and melphalan in 11 patients and other agents in 6 patients. All patients achieved neutrophil engraftment. The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) was 47%, and that of chronic GVHD was 70%. Relapse occurred in 1 patient. The major cause of death was transplant-related complication (n = 9). Overall survival and event-free survival at 5 years after HSCT were both 41%. In summary, this study indicates that HSCT is a curative therapy for some patients with sMDS/sAML after aplastic anemia. Future efforts should focus on reducing transplantation-related mortality.     

Protective Effect of Cytomegalovirus Reactivation on Relapse after Allogeneic Hematopoietic Cell Transplantation in Acute Myeloid Leukemia Patients Is Influenced by Conditioning Regimen

Cytomegalovirus (CMV) reactivation after allogeneic hematopoietic cell transplant (allo-HCT) has been associated with a reduced risk of relapse in patients with acute myeloid leukemia (AML). However, the influence of the conditioning regimen on this protective effect of CMV reactivation after allo-HCT is relatively unexplored. To address this, we evaluated the risk of relapse in 264 AML patients who received T cell–replete, 6/6 HLA matched sibling or 10/10 HLA matched unrelated donor transplantation at a single institution between 2006 and 2011. Of these 264 patients, 206 received myeloablative (MA) and 58 received reduced-intensity conditioning (RIC) regimens. CMV reactivation was observed in 88 patients with MA conditioning and 37 patients with RIC. At a median follow-up of 299 days, CMV reactivation was associated with significantly lower risk of relapse in patients who received MA conditioning both in univariate (P = .01) and multivariate analyses (hazard ratio, .5246; P = .006); however, CMV reactivation did not significantly affect the risk of relapse in our RIC cohort. These results confirm the protective effect of CMV reactivation on relapse in AML patients after allo-HCT reported by previous studies but suggest this protective effect of CMV reactivation on relapse is influenced by the conditioning regimen used with the transplant.     

Outcome of Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia Patients with Central Nervous System Involvement

Central nervous system (CNS) involvement in adult acute myeloid leukemia (AML) is rare and associated with poor outcomes. Therefore, CNS involvement in AML is an indicator for allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the impact of CNS involvement in AML on the outcome of allo-HSCT remains unclear. We performed a large-scale nationwide retrospective analysis to elucidate the outcomes of allo-HSCT on AML with CNS involvement (CNS+AML). Clinical data were collected from a registry database of the Japan Society for Hematopoietic Cell Transplantation. CNS involvement was defined as the infiltration of leukemia cells into the CNS or myeloid sarcoma in the CNS identified at any time from diagnosis to transplantation. One hundred fifty-seven patients with CNS+AML underwent allo-HSCT between 2006 and 2011. The estimated overall survival, cumulative incidence of relapse and nonrelapse mortality at 2 years for CNS+AML (51.2%, 30.2%, and 14.5%, respectively) were comparable with those for AML without CNS involvement (48.6%, 27.4%, and 22.0%, respectively). Univariate and multivariate analyses indicated that the development of chronic graft-versus-host disease, disease status, and cytogenetic risk category were independent prognostic factors for overall survival for CNS+AML. These results suggest that allo-HSCT may improve outcomes in patients with CNS+AML.     

Poor Outcome with Nonmyeloablative Conditioning Regimen before Cord Blood Transplantation for Patients with High-Risk Acute Myeloid Leukemia Compared with Matched Related or Unrelated Donor Transplantation

Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) is recommended for patients with high-risk acute myeloid leukemia (AML). In many situations, a matched related (MRD) or matched unrelated donor (MUD) is lacking, in which case unrelated cord blood units (UCB) provide an alternative. We analyzed the outcome of consecutive high-risk AML patients prepared with reduced-intensity conditioning (RIC) regimens and allografted with UCB (n = 32) and compared their outcome with high-risk AML patients who underwent transplantation with MRD/MUD (n = 49) in the same period of time. Grade III to IV acute graft-versus-host disease (GVHD) occurred slightly more frequently in the UCB group (25%) than in the MRD/MUD group (8%) (P = .069). Conversely, we found a lower incidence of extensive chronic GVHD in the UCB group (6%) than in the MRD/MUD group (20%, P = .085). Nonrelapse mortality at 4 years was 16% and 22% in the UCB and MRD/MUD groups, respectively (P = .529). The cumulative incidence of relapse at 4 years was significantly higher in the UCB group (60%) than in the MRD/MUD group (27%, P = .006). Leukemia-free survival (LFS) and overall survival (OS) at 4 years were 25% and 34%, respectively, in the UCB group and 50% and 56%, respectively, in the MRD/MUD group (LFS, P = .029; OS, P = .072). Multivariate analyses adjusted by cytogenetics and disease status at the time of Allo-HSCT revealed that use of UCB remained an independent predictive factor of shorter LFS (hazard ratio, 2.0; 95% confidence interval, 1.1 to 3.6; P = .018), and was associated with a trend for shorter OS (hazard ratio, 1.7; 95% confidence interval, .9 to 3.2; P = .093). Whereas UCB provides an alternative for patients with high-risk AML lacking an MRD/MUD, the high incidence of relapse after RIC-based UCB Allo-HSCT is a concern. Attempts to improve leukemic control with UCB Allo-HSCT are warranted, as well as the evaluation of other alternative donors in this context.     

Low CD34 Dose Is Associated with Poor Survival after Reduced-Intensity Conditioning Allogeneic Transplantation for Acute Myeloid Leukemia and Myelodysplastic Syndrome

Reduced-intensity conditioning/nonmyeloablative conditioning regimens are increasingly used in allogeneic hematopoietic cell transplantation (HCT). Reports have shown CD34⁺ dose to be important for transplantation outcome using myeloablative conditioning. The role of CD34⁺ dose of peripheral blood progenitor cells (PBPC) has not been previously analyzed in a large population undergoing reduced-intensity conditioning/nonmyeloablative HCT. We studied 1054 patients, ages 45 to 75 years, with acute myeloid leukemia or myelodysplastic syndrome who underwent transplantation between 2002 and 2011. Results of multivariate analysis showed that PBPC from HLA-matched siblings containing <4 × 10⁶ CD34⁺/kg was associated with higher nonrelapse mortality (hazard ratio [HR], 2.03; P = .001), overall mortality (HR, 1.48; P = .008), and lower neutrophil (odds ratio [OR], .76; P = .03) and platelet (OR, .76; P = .03) recovery. PBPC from unrelated donors with CD34⁺ dose < 6 × 10⁶ CD34⁺/kg was also associated with higher nonrelapse (HR, 1.38; P = .02) and overall mortality (HR, 1.20; P = .05). In contrast to reports after myeloablative HCT, CD34⁺ dose did not affect relapse or graft-versus-host disease with either donor type. An upper cell dose limit was not associated with adverse outcomes. These data suggest that PBPC CD34⁺ doses >4 × 10⁶ CD34⁺/kg and >6 × 10⁶ CD34⁺/kg are optimal for HLA-matched sibling and unrelated donor HCT, respectively.     

Allogeneic Hematopoietic Cell Transplantation May Alleviate the Negative Prognostic Impact of Monosomal and Complex Karyotypes on Patients with Acute Myeloid Leukemia

Monosomal karyotype (MK) and complex karyotype (CK) are well known to be associated with a very poor clinical outcome in patients with acute myeloid leukemia (AML). However, whether or not the prognostic impact of MK and CK remains relevant for patients who have undergone allogeneic hematopoietic cell transplantation (allo-HCT) is still unclear. We retrospectively analyzed the status of MK and CK, as well as other clinical laboratory features, in 148 allo-HCT AML patients at our institution and correlated with their event-free survival (EFS) and overall survival (OS) after transplantation. MK and CK were identified in 14 (9%) and 19 (13%) cases, respectively. On univariate analysis, only age (≥60 years) and WBC count (≥15 × 10⁹/L) were significant adverse predictors for EFS (P < .001 and P = .017, respectively) and OS (P = .002 and P = .021, respectively). MK, CK, and other relevant parameters analyzed did not affect the clinical outcome. Multivariable analysis confirmed that both older age and high WBC count were independent prognostic factors for a shorter OS (P = .001 and P = .003, respectively) and a shorter EFS (P < .001 and P = .001, respectively). Our results indicate that neither MK nor CK are high-risk factors in AML patients undergoing allo-HCT.     

Nonmyeloablative Allogeneic Hematopoietic Stem Cell Transplantation for GATA2 Deficiency

We treated 14 patients with GATA2 deficiency using a nonmyeloablative allogeneic hematopoietic stem cell transplantation regimen. Four patients received peripheral blood stem cells from matched related donors (MRD), 4 patients received peripheral blood stem cells from matched unrelated donors (URD), 4 patients received hematopoietic stem cells from umbilical cord blood donors (UCB), and 2 patients received bone marrow cells from haploidentical related donors. MRD and URD recipients received conditioning with 3 days of fludarabine and 200 cGy total body irradiation (TBI). Haploidentical related donor recipients and UCB recipients received cyclophosphamide and 2 additional days of fludarabine along with 200 cGY TBI. MRD, URD, and UCB recipients received tacrolimus and sirolimus for post-transplantation immunosuppression, whereas haploidentical recipients received high-dose cyclophosphamide followed by tacrolimus and mycophenolate mofetil. Eight patients are alive with reconstitution of the severely deficient monocyte, B cell, and natural killer cell populations and reversal of the clinical phenotype at a median follow-up of 3.5 years. Two patients (1 URD recipient and 1 UCB recipient) rejected the donor graft and 1 MRD recipient relapsed with myelodysplastic syndrome after transplantation. We are currently using a high-dose conditioning regimen with busulfan and fludarabine in patients with GATA2 deficiency to achieve more consistent engraftment and eradication of the malignant myeloid clones.     

伴骨髓增生异常相关改变的急性髓细胞白血病的免疫表型及临床特征

目的分析伴骨髓增生异常相关改变的急性髓细胞白血病(AML-MRC)的白血病相关免疫表型(LAIP)及临床特征。方法对117例初治AML患者进行重新WHO分型诊断,分析其中37例AML-MRC患者发病时经流式细胞术(FCM)检测的免疫表型结果,以45例非特殊类型AML(AML-NOS)患者为对照组。并对两组患者的发病年龄、骨髓原始细胞比例、WBC、Hb、PLT、染色体核型以及诱导化疗疗效进行比较。结果 AML-MRC组与AML-NOS组比较,其白血病相关免疫表型阳性检出率高。AML-MRC组患者骨髓原始细胞比例(40.6%vs.54.8%,P0.01)及WBC计数(19.2×109/L vs.49.2×109/L,P0.01)较AML-NOS组患者低,不良预后核型比例高(28.0%vs.0%,P0.01),CR率明显减低(22.7%vs.69.7%,P0.01)。结论 AML-MRC做为WHO新定义的一种类型,具有易于表达白血病相关免疫表型、不良预后核型比例高、常规化疗疗效不佳等特点。     

Comparison of Autologous Stem Cell Transplantation versus Haploidentical Donor Stem Cell Transplantation for Favorable- and Intermediate-Risk Acute Myeloid Leukemia Patients in First Complete Remission

Stem cell transplantation (SCT) is an attractive postremission treatment option for patients with intermediate-risk acute myeloid leukemia (AML) and for some favorable-risk AML patients with additional nongenetic risk factors. Autologous SCT (auto-SCT) and haploidentical donor SCT (haplo-SCT) are the widely used alternatives in cases of a lack of a HLA-matched donor. However, limited data have been published on the direct comparison between these 2 transplant types. Based on the transplant database in our center, we conducted a retrospective study involving patients with favorable- and intermediate-risk AML in first complete remission (CR1), according to the National Comprehensive Cancer Network guideline. Patients with extramedullary disease or those achieving CR by more than 2 cycles were excluded. In total, 195 patients were included in the study, 88 of whom underwent auto-SCT and 107 haplo-SCT. In the entire cohort analyses the impact of high relapse incidence in the auto-SCT group was compensated by low nonrelapse mortality (NRM), which resulted in a comparable overall survival (OS) (79.0%?±?4.6% versus 80.1%?±?5.0%, P?=?.769) and relapse-free survival (RFS) (66.1%?±?5.2% versus 77.4%?±?4.8%, P?=?.079) compared with those observed in the haplo-SCT group. However, for patients with intermediate-risk AML, NRM was similar between the groups, and haplo-SCT exhibited superior survival. In case of post-SCT relapse, patients with intermediate-risk AML showed markedly inferior 3-year OS compared with that shown by patients with favorable-risk AML (23.3%?±?9.8% versus 60.8%?±?14.3%, P?=?.011). In the multivariate analyses, minimal residual disease (MRD) measured by flow cytometry and gene mutation status before transplantation were independent predictors for both OS and RFS. We concluded that both auto-SCT and haplo-SCT were acceptable options for postremission treatment of patients with favorable- and intermediate-risk AML. Haplo-SCT yielded a better outcome in patients with intermediate-risk AML, but the relapse after SCT still led to a poor outcome. Clearance of MRD before SCT could improve the prognosis after transplantation.     

Busulfan Dose Intensity and Outcomes in Reduced-Intensity Allogeneic Peripheral Blood Stem Cell Transplantation for Myelodysplastic Syndrome or Acute Myeloid Leukemia

Comparisons of myeloablative conditioning versus reduced-intensity conditioning (RIC) have demonstrated a tradeoff between relapse and toxicity. Dose intensity across RIC regimens vary and may affect treatment outcomes. In this retrospective analysis, we investigated the effect of i.v. busulfan dosing (total dose 3.2 mg/kg versus 6.4 mg/kg) in RIC regimens that combined fludarabine and busulfan on outcomes in patients who were undergoing hematopoietic stem cell transplantation (HSCT) for myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). A total of 217 consecutive patients with MDS or AML underwent first busulfan and fludarabine RIC peripheral blood stem cell transplantation from well-matched related or unrelated donors at our institutions between 2004 and 2009. Of the 217 patients, 135 patients received Bu1 (3.2 mg/kg of busulfan) and 82 patients received Bu2 (6.4 mg/kg of busulfan), both with daily fludarabine (30 mg/m²/day for 4 days). The choice of RIC regimen was based on temporal institutional standard, enrollment on protocols, and physician choice. Patients had similar characteristics with a few notable differences: Patients who received Bu1 were younger (median age 61 versus 64 years, P < . 001), received more single-antigen mismatched unrelated grafts (14.1% versus 1.2%, P < . 001), received more sirolimus-based graft-versus-host disease (GVHD) prophylaxis regimens (63% versus 45%, P < .0001), received less antithymocyte globulin for GVHD prophylaxis (0% versus 22%, P < .001), and had less enrollment on a clinical trial that used prophylactic rituximab for the prevention of chronic GVHD (2.2% versus 11.0%, P = .011). Clinical disease status was similar between the groups. Median follow-up for survivors was 4.4 years for Bu1 and 3.2 years for Bu2. Because of the differences in characteristics, the 2 groups were compared with the adjustment of a propensity score that predicted Bu2 to account for measured differences. The day +200 cumulative incidence rates of grades II to IV acute GVHD (Bu1, 17%, versus Bu2, 8.5%; hazard ratio [HR], .56; 95% confidence interval [CI], .22 to 1.41; P = .22) or grades III to IV acute GVHD (Bu1, 6.7%, versus Bu2, 4.9%) were not different. The 2-year cumulative incidence of chronic GVHD was not significantly different between Bu1 and Bu2 (41.5% versus 28%, respectively; HR, .70; CI, .42 to 1.17; P = .09). Two-year nonrelapse mortality rates were similar for Bu1 and Bu2 (8.9% versus 9.8%, respectively; HR, .80; CI, .29 to 2.21; P = .67). Two-year progression-free survival and overall survival were also similar between Bu1 and Bu2 (progression-free survival: 40.6% versus 39.3%, respectively; HR, .82; CI, .57 to 1.30; P = .33; and overall survival: 47.4% versus 48.8%, respectively; HR, .96; CI, .64 to 1.44; P = .85). Subset analysis defined by clinical disease and cytogenetic risk with the propensity risk score applied suggest that in patients with high clinical disease risk and nonadverse cytogenetics, the higher dose busulfan RIC regimen may be of marginal benefit (2-year progression-free survival: HR, .54; CI, .29 to 1.03; P = .062). For the majority of patients with MDS or AML undergoing busulfan and fludarabine RIC peripheral blood stem cell transplantation, however, the dose of busulfan (3.2 mg/kg versus 6.4 mg/kg) is not associated with significant differences in overall outcomes.     

Biology-Driven Approaches to Prevent and Treat Relapse of Myeloid Neoplasia after Allogeneic Hematopoietic Stem Cell Transplantation

The curative potential of allogeneic hematopoietic cell transplantation (allo-HCT) in the treatment of acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) relies mainly on the graft-versus-leukemia effect. Relapse after allo-HCT occurs in a considerable proportion of patients and has a dismal prognosis, with still very limited curative potential. This review provides an overview of the established and evolving approaches to preventing or treating relapse of AML and MDS after allo-HCT, in the context of novel insight into the biology of relapse. Established prophylactic measures to prevent relapse include optimized conditioning and graft-versus-host disease (GVHD) prophylaxis, as well as donor lymphocyte infusion (DLI) for high-risk patients; novel immunomodulatory interventions and maintenance approaches are still experimental. Improved diagnostics can detect persistent or recurring disease at a molecular level, enabling early preemptive interventions. Established options include hypomethylating agents and DLI. Standard treatments for hematologic relapse include chemotherapy, cessation of immunosuppressive treatment, and DLI. Experimental approaches include molecular targeted therapies, novel immunomodulatory treatments, and second allo-HCT. For all interventions, the potential risks, including occurrence of GVHD, must be weighed against the benefits individually in each patient. Concurrently, prevention and treatment of relapse after allo-HCT remain challenging and unmet medical needs.     

HLA-Matched Sibling versus Unrelated versus Haploidentical Related Donor Allogeneic Hematopoietic Stem Cell Transplantation for Patients Aged Over 60 Years with Acute Myeloid Leukemia: A Single-Center Donor Comparison

Haploidentical related donor (HRD) allogeneic hematopoietic stem cell transplantation (allo-HSCT) was developed as a valid option for the treatment of acute myeloid leukemia (AML) in the absence of a matched donor. However, many investigators are reluctant to consider the use of this alternative in elderly patients, anticipating high morbidity. Here, we report a single-center comparison of HRD versus matched sibling donor (MSD) and unrelated donor (UD) allo-HSCT for patients with AML aged ≥60 years. Ninety-four patients (MSD: n?=?31; UD: n?=?30; HRD: n?=?33) were analyzed. The median age was 65 (range, 60 to 73) years. We observed a higher cumulative incidence of grade 3 to 4 acute graft-versus-host disease (GVHD) after UD allo-HSCT (MSD versus UD versus HRD: 3% versus 33% versus 6%, respectively; P?=?.006). Two-year cumulative incidence of moderate or severe chronic GVHD was 17%, 27%, and 16% in the MSD, UD, and HRD groups, respectively (P?=?.487). No difference was observed in the 2-year cumulative incidence of relapse or nonrelapse mortality (NRM) (relapse: MSD versus UD versus HRD: 32% versus 25% versus 25%, respectively; P?=?.411; NRM: MSD versus UD versus HRD: 19% versus 27% versus 24%, respectively; P?=?.709). At 2 years, progression-free survival, overall survival, and GVHD- and relapse-free survival were 48%, 50%, and 39%, respectively, in the MSD group; 48%, 51%, and 23%, respectively, in the UD group; and 50%, 52%, and 32%, respectively, in the HRD group, without statistically significant differences between the groups. We conclude that HRD allo-HSCT is highly feasible and no less efficient than MSD or UD allo-HSCT in patients with AML aged ≥60 years. Thus, the absence of a HLA-identical donor should not limit the consideration of allo-HSCT for the treatment of AML.     

Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients with Myelodysplastic Syndrome Harboring Trisomy 8

Trisomy 8 (+8) is 1 of the most common cytogenetic abnormalities in adult patients with myelodysplastic syndrome (MDS). However, the outcome of allogeneic hematopoietic stem cell transplantation (HSCT) in adult patients with MDS harboring +8 remains unclear. To evaluate the outcome and prognostic factors in patients with MDS harboring +8 as the sole cytogenetic abnormality or in association with other abnormalities, we retrospectively analyzed the Japanese registration data of 381 adult patients with MDS harboring +8 treated with allogeneic HSCT between 1990 and 2013. With a median follow-up period of 53 months, the probability of overall survival and cumulative incidence of relapse at 4 years were 51% and 22%, respectively. In the multivariate analysis, age > 50 years, 2 or more additional cytogenetic abnormalities, and a high risk at the time of HSCT according to the FAB/WHO classification were significantly associated with a higher overall mortality. Nevertheless, no significant impact of the outcome was observed in patients with 1 cytogenetic abnormality in addition to +8. Although 221 patients (58%) had advanced MDS at the time of HSCT, allogeneic HSCT offered a curative option for adult patients with MDS harboring +8.