Extramedullary Relapse of Acute Leukemia after Haploidentical Hematopoietic Stem Cell Transplantation: Incidence,Risk Factors,Treatment, and Clinical Outcomes

We examined the incidence, risk factors, treatment, and clinical outcomes of extramedullary relapse (EMR) in 961 acute leukemia patients undergoing HLA-haploidentical hematopoietic stem cell transplantation (haplo-HSCT) between 2002 and 2013. Multiple control subjects were selected at random from the same cohort and matched to EMR cases for diagnosis, disease status at HSCT, age at the time of the HSCT, and year of HSCT. Forty patients exhibited EMR, with a median time to EMR of 207 days. The cumulative incidence of EMR was 4.0% at 3 years, and the incidence was higher in acute lymphoblastic leukemia patients compared with acute myeloid leukemia patients (5.6% versus 2.4%). In the multivariate analysis, non–complete remission (CR) status at HSCT (hazard ratio [HR] = 4.6; P = .018) and non–chronic graft-versus-host disease after HSCT (HR = 3.2; P < .001) were the independent risk factors for EMR after haplo-HSCT. Twenty-seven patients received combination treatments, and the proportion of patients who achieved CR was higher than those who received single treatment. Multifocal involvement at EMR (HR = 2.7; P = .024) and non-CR after EMR treatments (HR = 4.6; P < .001) were the independent risk factors for poor survival rates among EMR patients. We found that graft-versus-leukemia effect may help to prevent EMR after haplo-HSCT.     

Extramedullary Relapse of Acute Myelogenous Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation

The clinical significance of extramedullary relapse (EMR) of acute myelogenous leukemia (AML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains poorly defined. Here we report the clinical outcomes of patients who underwent allo-HSCT for AML at our institution between 2000 and 2012. A total of 293 patients with AML who underwent allo-HSCT were included. The median duration of follow-up in survivors was 1840 days. Disease status at the time of allo-HSCT was complete remission in 192 patients and nonremission in 101 patients. A total of 110 patients experienced AML relapse after allo-HSCT, including 18 with EMR only, 83 with bone marrow relapse (BMR) only, and 9 with both EMR and BMR. The 5-year cumulative incidence of EMR after allo-HSCT was 9.5%, whereas that of BMR only was 28.9%. In multivariate analysis, peripheral blood stem cell transplantation was associated with an increased risk of EMR. The 2-year overall survival after post-transplantation relapse was 7.5% in patients with BMR only, 11.1% in those with both EMR and BMR, and 27.5% in those with EMR only (P < .05). Although the short-term survival was better in patients with EMR only, they rarely achieved long-term survival. Appropriate strategies for both post-transplantation EMR and BMR are needed.     

Second Hematopoietic Stem Cell Transplantation for Post-Transplantation Relapsed Acute Leukemia in Children: A Retrospective EBMT-PDWP Study

Outcome data were collected from the European Society for Blood and Marrow Transplantation registry on 373 children from 120 centers with relapsed leukemia (214 with acute lymphoblastic leukemia [ALL] and 159 with acute myelogenous leukemia [AML]) who underwent second allogeneic hematopoietic stem cell transplantation (HSCT) between 2004 and 2013. Overall survival (OS) was 38% at 2 years and 29% at 5 years, and leukemia-free survival (LFS) was 30% at 2 years and 25% at 5 years. Median follow-up after second HSCT was 36.4 months in the ALL group and 50.2 months in the AML group. In the ALL group, OS was 43% at 2 years and 33% at 5 years, and LFS was 34% at 2 years and 31% at 5 years. In the AML group, OS was 32% at 2 years and 24% at 5 years, and LFS was 24% at 2 years and 17% at 5 years. The 2-year nonrelapse mortality (NRM) rate was 22% in the ALL group and 18% in the AML group. Favorable prognostic factors (P?<?.05) for OS and LFS included >12 months between transplantations and chronic graft-versus-host disease after the first HSCT (in both groups), complete response before the second HSCT (ALL group only), and age >12 years (AML group only). Findings were more consistent over time in the ALL group, with no significant differences between 2-year and 5-year rates of relapse, NRM, and LFS. Children with relapsed acute leukemias have a substantial likelihood of long-term survival following second HSCT. Given the many novel targeted and immunomodulation therapies currently under development, it is important to identify specific patient subpopulations that may benefit from a second HSCT compared with those better suited to new approaches.     

Superior Survival of Unmanipulated Haploidentical Hematopoietic Stem Cell Transplantation Compared with Chemotherapy Alone Used as Post-Remission Therapy in Adults with Standard-Risk Acute Lymphoblastic Leukemia in First Complete Remission

We wanted to compare the efficacy of haploidentical hematopoietic stem cell transplantation (HSCT) with chemotherapy alone in adults with standard-risk acute lymphoblastic leukemia (ALL) in first complete remission (CR1). One hundred thirty-eight consecutive adult patients with standard-risk ALL in CR1 were retrospectively investigated. Of these patients, 59 received chemotherapy alone (group A) and 79 received unmanipulated haploidentical HSCT (group B). Cumulative incidence of relapse at 5 years in group A was significantly higher than that in group B (66.3% versus 29.9%, P < .0001). Overall and disease-free survival in group A were significantly inferior to group B (P < .0001). Moreover, multivariate analyses demonstrated that central nervous system leukemia (P = .002), T cell immunophenotype (P = .044), expression of E2A-PBX1 (P = .007), and positive minimal residual disease after the first cycle of consolidation (P = .004) were correlated with relapse. Patients with 1 of 4 risk factors were assigned to the high-risk group. Otherwise, patients without risk factors were assigned to the low-risk group. In the high-risk group, HSCT had lower relapse rates and superior DFS compared with chemotherapy (P < .05), but in the low-risk group, there were no differences between HSCT and chemotherapy (P > .05). This study is the first to demonstrate that compared with chemotherapy alone, haploidentical HSCT is a better postremission therapy in adults with standard-risk ALL in CR1. Moreover, based on the 4 risk factors, the establishment of risk stratification could identify the subgroup of patients with a higher risk of relapse in adults with standard-risk ALL in CR1. Furthermore, risk stratification–directed postremission therapies using haploidentical HSCT or chemotherapy alone not only reduce relapse rate but also avoid unnecessary treatment-related mortality and improve survival.     

Central Nervous System Relapse in Adults with Acute Lymphoblastic Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation

Central nervous system (CNS) relapse after allogeneic hematopoietic stem cell transplantation (HSCT) confers a poor prognosis in adult patients with acute lymphoblastic leukemia (ALL). Preventing CNS relapse after HSCT remains a therapeutic challenge, and criteria for post-HSCT CNS prophylaxis have not been addressed. In a 3-center retrospective analysis, we reviewed the data for 457 adult patients with ALL who received a first allogeneic HSCT in first or second complete remission (CR). All patients received CNS prophylaxis as part of their upfront therapy for ALL, but post-transplantation CNS prophylaxis practice varied by institution and was administered to 48% of the patients. Eighteen patients (4%) developed CNS relapse after HSCT (isolated CNS relapse, n = 8; combined bone marrow and CNS relapse, n = 10). Patients with a previous history of CNS involvement with leukemia had a significantly higher rate for CNS relapse (P = .002), and pretransplantation CNS involvement was the only risk factor for post-transplantation CNS relapse found in this study. We failed to find a significant effect of post-transplantation CNS prophylaxis to prevent relapse after transplantation. Furthermore, no benefit for post-transplantation CNS prophylaxis could be detected when a subgroup analysis of patients with (P = .10) and without previous CNS involvement (P = .52) was performed. Finally, we could not find any significant effect for intensity of the transplantation conditioning regimen on CNS relapse after HSCT. In conclusion, CNS relapse is an uncommon event after HSCT for patients with ALL in CR1 or CR2, but with higher risk among patients with CNS involvement before transplantation. Furthermore, neither the use of post-HSCT CNS prophylaxis nor the intensity of the HSCT conditioning regimen made a significant difference in the rate of post-HSCT CNS relapse.     

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.     

Unrelated Cord Blood Transplantation for Acute Leukemia Diagnosed in the First Year of Life: Outcomes and Risk Factor Analysis

Infant acute leukemia still has a poor prognosis, and allogeneic hematopoietic stem cell transplantation is indicated in selected patients. Umbilical cord blood (UCB) is an attractive cell source for this population because of the low risk of chronic graft-versus-host disease (GVHD), the strong graft-versus-leukemia effect, and prompt donor availability. This retrospective, registry-based study reported UCB transplantation (UCBT) outcomes in 252 children with acute lymphoblastic leukemia (ALL; n?=?157) or acute myelogenous leukemia (AML; n?=?95) diagnosed before 1 year of age who received a single-unit UCBT after myeloablative conditioning between 1996 and 2012 in European Society for Blood and Marrow Transplantation centers. Median age at UCBT was 1.1 years, and median follow-up was 42 months. Most patients (57%) received a graft with 1 HLA disparity and were transplanted in first complete remission (CR; 55%). Cumulative incidence function (CIF) of day 100 acute GVHD (grades II to IV) was 40%?±?3% and of 4-year chronic GVHD was 13%?±?2%. CIF of 1-year transplant-related mortality was 23%?±?3% and of 4-year relapse was 27%?±?3%. Leukemia-free-survival (LFS) at 4 years was 50%?±?3%; it was 40% and 66% for those transplanted for ALL and AML, respectively (P?=?.001). LFS was better for patients transplanted in first CR, regardless of diagnosis. In multivariate model, diagnosis of ALL (P?=?.001), advanced disease status at UCBT (<.001), age at diagnosis younger than 3 months (P?=?.012), and date of transplant before 2004 were independently associated with worse LFS. UCBT is a suitable option for patients diagnosed with infant acute leukemia who achieve CR. In this cohort, patients with AML had better survival than those with ALL.     

Treatment of Acute Leukemia with Unmanipulated HLA-Mismatched/Haploidentical Blood and Bone Marrow Transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains one of the best therapeutic options to cure acute leukemia (AL). However, many patients have no human leukocyte antigen (HLA)-matched donor. Recently, we developed a new method for HLA-mismatched/haploidentical transplantation without in vitro T cell depletion (TCD). This method combined granulotyce-colony stimulating factor (G-CSF)-primed bone marrow and peripheral blood with intensive immunosuppression. We analyzed the outcome of 250 consecutive patients with AL who underwent HLA-mismatched/haploidentical transplantation with 1-3 mismatched loci of HLA-A, B, and DR from family donors via our new transplant protocol. Two hundred forty-nine patients achieved sustained, full donor chimerism. The incidence of grade 2-4 acute graft-versus-host disease (aGVHD) was 45.8%, and that of grades 3 and 4 was 13.4%, which was not associated with the extent of HLA disparity. The cumulative incidence of total chronic GVHD (cGVHD) was 53.9% and that of extensive cGVHD was 22.6% in 217 evaluable patients. One hundred forty-one of the 250 patients survived free of disease recurrence at a median of 1092 days (range: 442-2437 days) of follow-up. Seventeen patients received DLI as a treatment for relapse after transplantation and 7 patients achieved leukemia-free survival (LFS). The 3-year probability of LFS for acute myelogenous leukemia (AML) was 70.7% and 55.9%, and for acute lymphoblastic leukemia (ALL) it was 59.7% and 24.8% in standard-risk and high-risk groups, respectively. Lower LFS were associated with diagnosis of acute leukemia in the high-risk group (P = .001, relative risk [RR], 95% confidence interval [CI]: 2.94[1.535-5.631]) and the occurrence of aGVHD of grades 3 and 4 (P = .004). HLA-mismatched/haploidentical HSCT was feasible with unmanipulated blood and bone marrow harvest.     

Donor Lymphocyte Infusion for the Treatment of Relapsed Acute Myeloid Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation: A Retrospective Analysis by the Adult Acute Myeloid Leukemia Working Group of the Japan Society for Hematopoietic Cell Transplantation

Because the efficacy of donor lymphocyte infusion (DLI) for acute myeloid leukemia (AML) relapse after allogeneic hematopoietic stem cell transplantation (HSCT) remains uncertain, especially in the Asian population, a nationwide registry study was retrospectively performed by the Adult AML Working Group of the Japan Society for Hematopoietic Cell Transplantation to identify the factors affecting the patient survival after DLI. Among 143 adult AML patients who received DLI for the treatment of first hematological relapse after HSCT, the overall survival rates at 1 year, 2 years, and 5 years were 32% ± 4%, 17% ± 3%, and 7% ± 3%, respectively. Complete remission (CR) at the time of DLI, which was obtained in 8% of the patients, was the strongest predictive factor for survival after DLI. Therefore, long-term survival after DLI was achieved almost exclusively in patients who successfully achieved a CR before DLI, indicating the limited efficacy of DLI in a minority of patients.     

Mobilization-Driven Postconsolidation Therapy in Elderly Patients with Acute Myeloid Leukemia: Feasibility and Efficacy of Autologous Stem Cell Transplantation versus Low-Dose Gemtuzumab Ozogamicin

We prospectively evaluated 2 postconsolidation strategies, administered according to the mobilization outcome, in 72 acute myeloid leukemia (AML) fit elderly patients, achieving complete remission after the first high-dose cytarabine-based induction. Autologous stem cell transplantation (ASCT) was performed in patients collecting ≥3 × 10⁶ CD34⁺/kg and low-dose gemtuzumab ozogamicin (GO) was performed in poor mobilizers (collecting <3 × 10⁶ CD34⁺/kg). Fifty-five patients (76.3%) underwent peripheral blood stem cell (PBSC) mobilization, after first consolidation, and 24 of 55 (44%) collected >3 × 10⁶ CD34⁺ cells/kg. Among the 55 patients eligible for PBSC mobilization, 7 did not receive the planned treatment, 23 were allocated for ASCT, and 25 were allocated for GO on an intention-to-treat basis. With a median follow-up of 70 months (range, 24 to 124), 20 of 55 patients are alive, 18 of them in continuous complete remission. The 8-year overall survival (OS) and disease-free survival (DFS) are, respectively, 35.9% (95% confidence interval [CI] 24% to 49.8%) and 31.2% (95% CI, 21% to 43.8%), median OS and DFS were 22 and 16 months, respectively. In multivariate analysis, postconsolidation treatment and hyperleukocytosis (WBC > 50,000/μL) significantly predicted OS and DFS, whereas secondary AML was significantly associated with a higher relapse rate (83.4% versus 54% of de novo AML). Patients with hyperleukocytosis had 0% 3-year OS versus the 46% (at 8 years) in patients without hyperleukocytosis (P = .01); 57% of patients in the GO arm are alive at 8 years, compared with 25.4% of patients in the ASCT arm, who had an overall relative risk (RR) of death of 2.6 (95% CI, 1.2 to 5.8; P = .02). DFS at 8 years was 45.3% in patients receiving GO, compared with 26% in ASCT arm (RR, 2.1; 95% CI, 1 to 4.3; P = .05). Our study outlines low feasibility and efficacy of ASCT in elderly AML patients, whereas postconsolidation with GO appears safe and effective in this unfavorable setting. The study was registered at Umin Clinical Trial Registry (www.umin.ac.jp/ctr), number R000014052.     

Myeloablative Cord Blood Transplantation in Adults with Acute Leukemia: Comparison of Two Different Transplant Platforms

We compared the clinical outcomes of adults with acute leukemia that received single-unit umbilical cord blood transplantation (sUCBT) after conditioning with a busulfan/antithymocyte globulin (BU-ATG)–based regimen at University Hospital La Fe (n = 102) or double-unit UCBT (dUCBT) after conditioning with a total body irradiation (TBI)–based regimen at the University of Minnesota (n = 91). Nonrelapse mortality, relapse and disease-free survival were similar in the 2 groups. Multivariate analyses, showed more rapid neutrophil (hazard ratio [HR], .6; 95% confidence interval [CI], .45 to .80; P = .0006) and platelet recovery (HR, .59; 95% CI, .43 to.83; P = .002) after the BU-ATG-based conditioning and sUCBT. Although there was a lower risk of acute graft-versus-host disease (GVHD) grade II to IV (HR, 2.81; 95% CI, 1.75 to 4.35; P < .001) after BU-ATG and sUCBT, the incidences of grade III to IV acute and chronic GVHD were similar between the 2 groups. Regarding disease-specific outcomes, disease-free survival in both acute myeloid leukemia and acute lymphoblastic leukemia (ALL) patients were not significantly different; however, a significantly lower relapse rate was found in patients with ALL treated with TBI and dUCBT (HR, .3; 95% CI, .12 to .84; P = .02). In the context of these specific treatment platforms, our study demonstrates that sUCB and dUCBT offer similar outcomes.     

Outcomes of Adults with Acute Lymphoblastic Leukemia Relapsing after Allogeneic Hematopoietic Stem Cell Transplantation

For patients with acute lymphoblastic leukemia (ALL) who relapse after allogeneic hematopoietic stem cell transplantation (HSCT), treatment options are limited, and the clinical course and prognostic factors affecting outcome have not been well characterized. We retrospectively analyzed outcomes of 123 adult patients with ALL who relapsed after a first HSCT performed at our center between 1993 and 2011. First-line salvage included second HSCT (n = 19), donor lymphocyte infusion with or without prior chemotherapy (n = 11), radiation therapy (n = 6), cytoreductive chemotherapy (n = 30), mild chemotherapy (n = 27), or palliative care (n = 23), with median postrelapse overall survival (OS) of 10 months, 6.5 months, 3 months, 4 months, 4 months, and 1 month, respectively. Despite a complete remission rate of 38% after first-line salvage in the treated patients, the OS rate remained limited with 1- and 2- year OS rates of 17% (95% confidence interval, 13 to 29) and 10% (95% confidence interval, 6 to 20), respectively. On univariate analysis, adverse factors for OS included active disease at the time of first HSCT and short time to progression from first HSCT (<6 months). There was no difference in the 6-month survival postrelapse in patients with isolated extramedullary relapse (44%) compared with combined extramedullary and bone marrow relapse (29%) or those with isolated bone marrow relapse (34%) (P = .8). Our data provide more insight into the disease behavior and treatment outcomes of ALL at relapse after HSCT against which future trials may be compared.     

Impact of Pretransplantation Risk Factors on Post Transplantation Outcome of Patients with Acute Myeloid Leukemia in Remission after Haploidentical Hematopoietic Stem Cell Transplantation

The impact of risk-related parameters has not been defined in transplantation settings. We wondered whether the currently recognized predictors could be used to categorize acute myeloid leukemia (AML) patients who underwent transplantation during remission into risk groups. We analyzed the data of 255 consecutive patients (median age, 26) with AML in their first or second remission (CR1 or CR2) after haploidentical hematopoietic stem cell transplantation (HSCT). Three parameters were found to be predictive of outcome: response after induction therapy, white blood cell count at diagnosis, and cytogenetics. These three factors were combined to yield two risk groups. The 2-year cumulative incidences of relapse for patients at low and high risk were 8% and 36% (P = .001), respectively. The 3-year probabilities of leukemia-free survival for these two groups were 80% and 52% (P = .001), respectively. Multivariate analysis for relapse and for leukemia-free survival showed that not achieving CR after two courses of therapy was the strongest independent prognostic factor (P = .001 and P = .028, respectively). In addition, in a subgroup of patients with quantification of minimal residual disease at the time of HSCT, positive minimal residual disease at this time point was correlated with a poor outcome. Our results suggest that the pretransplantation risk factors influence posttransplantation outcomes of patients with AML in CR after haploidentical HSCT and might be applicable to assist with risk-directed posttransplantation therapy.     

Phase I Trial of Maintenance Sorafenib after Allogeneic Hematopoietic Stem Cell Transplantation for Fms-like Tyrosine Kinase 3 Internal Tandem Duplication Acute Myeloid Leukemia

The fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD) mutation is associated with a high relapse rate for patients with acute myeloid leukemia (AML) even after allogeneic hematopoietic stem cell transplantation (HSCT). Sorafenib is a tyrosine kinase inhibitor, which inhibits the FLT3 tyrosine kinase and has shown encouraging activity in FLT3-ITD AML. We conducted a phase I trial of maintenance sorafenib after HSCT in patients with FLT3-ITD AML (ClinicalTrials.gov NCT01398501). Patients received a variety of conditioning regimens and graft sources. A dose escalation 3 + 3 cohort design was used to define the maximum tolerated dose (MTD), with an additional 10 patients treated at the MTD. Sorafenib was initiated between days 45 and 120 after HSCT and continued for 12 28-day cycles. Twenty-two patients were enrolled (status at HSCT: first complete remission [CR1], n = 16; second complete remission [CR2], n = 3; refractory, n = 3). The MTD was established at 400 mg twice daily with 1 dose-limiting toxicity (DLT) observed (pericardial effusion). Two patients died of transplantation-related causes, both unrelated to sorafenib. Two patients stopped sorafenib after relapse and 5 stopped because of attributable toxicities after the DLT period. Median follow-up for surviving patients is 16.7 months after HSCT (range, 8.1 to 35.0). There was 1 case of grade II acute graft-versus-host disease (GVHD) after starting sorafenib and the 12-month cumulative incidence of chronic GVHD was 38% (90% confidence interval [CI], 21% to 56%). For all patients, 1-year progression-free survival (PFS) was 85% (90% CI, 66% to 94%) and 1-year overall survival (OS) was 95% (90% CI, 79% to 99%) after HSCT. For patients in CR1/CR2 before HSCT (n = 19), 1-year PFS was 95% (90% CI, 76% to 99%) and 1-year OS was 100%, with only 1 patient who relapsed. Sorafenib is safe after HSCT for FLT3-ITD AML and merits further investigation for the prevention of relapse.     

Allocation to Matched Related or Unrelated Donor Results in Similar Clinical Outcomes without Increased Risk of Failure to Proceed to Transplant among Patients with Acute Myeloid Leukemia: A Retrospective Analysis from the Time of Transplant Approval

Clinical outcomes after allogeneic hematopoietic stem cell transplantation (allo-SCT) from unrelated donors (URDs) approach those of matched related donor (MRD) transplants in patients with acute myeloid leukemia (AML). Yet, available data fail to account for differences in pretransplantation outcomes between these donor selection strategies. In this regard, URD allo-HSCT is associated with longer waiting times to transplantation, potentially resulting in higher probabilities of failure to reach transplant. We retrospectively analyzed 108 AML patients accepted for first allo-HSCT from the time of approval to proceed to transplant. Fifty-eight (54%) patients were initially allocated to MRD, while URD search was initiated in 50 (46%) patients. Time to transplant was longer in patients allocated to a URD when compared with patients assigned to an MRD (median 142 days versus 100 days; p < .001). Forty-three of 58 (74%) patients in the MRD group and 35 of 50 (70%) patients in the URD group underwent transplantation (odds ratio [OR], 1.22; p?=?.63). Advanced disease status at the time of allo-HSCT approval was the only predictor of failure to reach transplantation in the multivariate analysis (OR, 4.78; p?=?.001). Disease progression was the most common cause of failure to reach allo-HSCT (66.7%) in both the MRD and URD groups. With a median follow-up from transplantation of 14.5 (interquartile range, 5 to 29) months, the 2-year estimate of overall survival (OS) from allo-HSCT was 46% in the MRD group and 57% in the URD group (p?=?.54). There were no differences in OS according to donor type allocation in the multivariate analysis (hazard ratio, 1.01; p?=?.83). When including patients from the time of transplant approval, 2-year OS was 39% in the MRD group versus 42% in the URD group. Our study suggests that allocation of AML patients to URDs may result in comparable clinical outcomes to MRD assignment without a significant increase in the risk of failure to reach transplant.     

Stratification of de novo Adult Acute Myelogenous Leukemia with Adverse-Risk Karyotype: Can We Overcome the Worse Prognosis of Adverse-Risk Group Acute Myelogenous Leukemia with Hematopoietic Stem Cell Transplantation?

Karyotype is a powerful prognostic factor for complete remission (CR) and overall survival (OS) in acute myelogenous leukemia (AML). Adverse-risk karyotype AML is now treated with intensive chemotherapy followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT) to overcome relapse. We attempted to stratify patients with this disease using a combination of known factors. We evaluated clinical correlates in 211 adults with AML and adverse-risk karyotypes. We divided the patients into several subgroups based on the number of chromosomal aberrations (NCAs), normal karyotype (NK) mosaicism, and monosomal karyotype (MK) status. CR rates and survival outcomes were compared among the subgroups, and the relapse rate was calculated in the allo-HSCT subgroup. The cutoff of NCA ≥5 showed the worst OS (P < .001) compared with NCA ≥3 or NCA ≥4 even after allo-HSCT. NK mosaicism significantly improved OS in both the NCA <5 (P = .024) and NCA ≥5 (P = .030) subgroups, but after allo-HSCT, it showed a favorable effect only in the NCA <5 subgroup. MK showed worse OS (P = .041), but there was no significantly worse effect after allo-HSCT compared with non-MK. Finally, we stratified patients into 4 subgroups, NCA ≥5 and NCA <5 with and without NK mosaicism. The most favorable OS and lower relapse rate after allo-HSCT were achieved by the NCA <5 with NK mosaicism subgroup, and the NCA ≥5 without NK mosaicism subgroup showed the worst prognosis in both entire group and allo-HSCT subgroup analysis. This study reveals that the combination of NCA and NK mosaicism may predict survival outcomes accurately, and suggests that novel treatment strategies for highly adverse-risk group AML should be tailored in the future.     

Comparison of Characteristics of Bacterial Bloodstream Infection between Adult Patients with Allogeneic and Autologous Hematopoietic Stem Cell Transplantation

Although autologous and allogeneic hematopoietic stem cell transplantation (HSCT) are fundamentally different procedures, a tailored approach to bacterial bloodstream infection (BSI) according to the type of HSCT has not yet been suggested. We evaluated the characteristics of BSI after HSCT, with a focus on comparison of BSIs between recipients of autologous HSCT (auto-HSCT) and allogeneic HSCT (allo-HSCT). Among 134 patients (59 received allo-HSCT and 75 received auto-HSCT) who underwent HSCT, BSIs were reported earlier in patients who underwent auto-HSCT, compared with those who underwent allo-HSCT (mean 12.1 ± 3.4 days versus 32.8 ± 27.1 days, P = .006). Among patients receiving allo-HSCT, postneutrophil-engraftment bacterial BSI showed an association with grade ≥2 acute graft-versus-host disease (GVHD). In patients who underwent auto-HSCT, results of multivariate analysis showed that not receiving prophylactic antibiotics (P = .004) and having elevated serum C-reactive protein (P = .034) were risk factors of BSI. Elevated CRP (P = .01) and acute GVHD ≥ grade 2 (P = .002) were independent risk factors in patients who underwent allo-HSCT. Those differences originated mainly from the impact of acute GVHD-related postengraftment BSIs of patients who underwent allo-HSCT. To establish the best defense strategy against BSI, the distinctive natures of bacterial BSI after HSCT between auto-HSCT and allo-HSCT should be considered.     

Extramedullary Relapse of Acute Myelogenous Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation: Better Prognosis Than Systemic Relapse

Allogeneic hematopoietic cell transplantation (HSCT) is considered a curative treatment for acute myelogenous leukemia (AML). Extramedullary relapse after HSCT for AML is a rare event and is less well defined than systemic, hematologic relapse. We retrospectively studied all patients with AML (n = 436) who underwent HSCT at the University of Minnesota between 1996 and 2008 who developed either a bone marrow (BM) or extramedullary (EM) relapse, and examined the incidence and risk factors for BM and EM relapse. Of 128 patients who relapsed post-HSCT, 25 had relapse in EM sites, either isolated (n = 13) or with concurrent BM relapse (n = 12). Relapse sites included bone (n = 1), central nervous system (n = 6), gastrointestinal (n = 4), lymphatic (n = 4), skin (n = 5), genitourinary (n = 1), pulmonary (n = 1), and soft tissue (n = 3). The time to relapse was longer in the EM sites (median, 328 days vs 168 days). Patients with EM relapse were more likely to have had preceding acute graft-versus-host disease (GVHD) (77% vs 49%; P = .03) or chronic GVHD (46% vs 15%; P = .02) compared with those with BM relapse. The 6-month survival postrelapse was significantly better in patients with isolated EM relapse (69%) compared with those with combined EM and BM relapse (8%) or those with BM relapse alone (27%) (P < .01). Compared with local therapy alone, systemic therapy yielded better 6-month survival in patients with EM relapse. This study suggests differing pathogenesis of BM relapse versus EM relapse of AML after allogeneic HSCT. GVHD and its accompanying graft-versus-leukemia effect may better protect BM sites, but patients with EM relapse have better responses to combined therapy and improved survival compared with those with BM relapse.     

Central Nervous System Relapse of Leukemia after Allogeneic Hematopoietic Stem Cell Transplantation

Little information is available regarding central nervous system (CNS) relapse of adult leukemia after allogeneic hematopoietic stem cell transplantation (HSCT). Therefore, we reviewed the data of 1226 patients with acute myelogenous leukemia (AML), acute lymphoblastic leukemia (ALL), and chronic myelogenous leukemia (CML) who received first allogeneic HSCT between 1994 and 2004, using the database of the Kanto Study Group for Cell Therapy (KSGCT), and analyzed the incidence, risk factors, and outcome of patients with CNS relapse. Twenty-nine patients developed CNS relapse at a median of 296 (9-1677) days after HSCT with a cumulative incidence of 2.3%. Independent significant factors associated with CNS relapse included ALL as the underlying diagnosis (relative risk [RR] = 9.55, 95% confidence interval [CI] = 1.26-72.2, P = .029), nonremission at HSCT (RR = 2.30, 95% CI = 1.03-5.15, P = .042), the history of CNS invasion before HSCT (RR = 5.62, 95% CI = 2.62-12.0, P = 9.2 × 10⁻⁶), and the prophylactic intrathecal chemotherapy after HSCT (RR = 2.57, 95% CI = 1.21-5.46, P = .014). The 3-year overall survival (OS) after CNS relapse was 18%. In 7 of 29 patients with CNS relapse, leukemia was observed only in CNS. Three of 7 patients were alive without systemic relapse, resulting in 3-year survival after CNS relapse of 46%. Although the outcome of patients with CNS relapse was generally poor, long-term disease-free survival could be achieved in some patients.