Byung-Sik Cho

Validation of recently proposed consensus criteria for thrombotic microangiopathy after allogeneic hematopoietic stem-cell transplantation.

Background. The lack of an accepted definition of transplantation-associated thrombotic microangiopathy (TMA) has led the Blood and Marrow Transplants Clinical Trials Network (CTN) and International Working Group (IWG) to propose a definition for TMA with some differences. However, there have been few studies validating and comparing both newly proposed criteria for TMA. Methods. To validate recently proposed criteria for TMA by CTN and IWG, we analyzed 672 patients who underwent allogeneic stem-cell transplantation between January 2002 and December 2006. Results. The cumulative incidences of TMA by CTN and IWG were 6.1% and 2.5%, respectively. The cumulative incidence of overall TMA (O-TMA) including probable-TMA defined as meeting CTN criteria without renal or neurologic dysfunction, as well as TMA by CTN (definite-TMA), was 12.7%. Sixty-six percent of TMA by CTN did not have any degree of schistocytosis by IWG criteria (≥4%), and 18% of TMA by IWG criteria did not have renal or neurologic dysfunction. On multivariate analyses, probable-TMA as well as definite-TMA adversely affected the survival of a cohort including all patients. In patients with O-TMA, the degree of schistocytosis (≥4% or not) failed to show prognostic significance, whereas renal involvement was a significant prognostic factor associated with poor survival. Conclusions. Both proposed consensus criteria have major pitfalls in their use as uniformly accepted diagnostic criteria for TMA. The use of O-TMA as a broad definition for TMA and the grading system by the presence of renal involvement may be a counterproposal for future trials.

Successful Prevention of Acute Graft-versus-Host Disease Using Low-Dose Antithymocyte Globulin after Mismatched, Unrelated, Hematopoietic Stem Cell Transplantation for Acute Myelogenous Leukemia

In this study, we investigated the effects of low-dose antithymocyte globulin (ATG, thymoglobulin) in the prevention of acute graft-versus-host disease (aGVHD) in mismatched, unrelated hematopoietic stem cell transplantations (uHSCTs) in patients with the single disease entity of acute myelogenous leukemia (AML). Patients (n = 103) with a variable risk for AML who received uHSCTs from available Asian and Caucasian donors were enrolled. First, we compared HLA-matched (group 1, n = 54) and HLA-mismatched (group 2, n = 49) transplantation patients. Then, we divided the patients in group 2, who had received transplants from allele(s)/antigen-mismatched donors, into 2 subgroups: patients who used ATG (group 3, n = 24) and those who did not (group 4, n = 25). To prevent the development of aGVHD, the patients in group 3 received ATG at a dose of 1.25 mg/kg body weight per day for 2 consecutive days, together with our standard regimen of methotrexate (MTX) and tacrolimus. The median CD34(+) cell infusion was 4.2 x 10(6)/kg (range: 1.2-34.4). The median patient age was 41 years (range: 16-57), and the median follow-up duration of patients who were event-free survivors was 23 months (range: 2-72). The overall incidences of aGVHD and chronic GVHD (cGVHD) were 38% and 56%, respectively. Of 48 evaluable patients in group 2, 10 (21%) developed moderate to severe aGVHD (grades II-IV). In contrast, 2 (8%) of the 24 patients in group 3 and 7 (29%) of the 24 evaluated patients in group 4 required therapy for aGVHD (grades II-IV; P = .038). The incidence of cGVHD was not different between groups 3 and 4. The estimated probabilities of overall survival (OS) and event-free survival (EFS) at 2 years for group 2 were 55% and 44%, respectively. In comparison, the estimated probabilities of OS and EFS at 2 years for groups 3 and 4 were 68% versus 38% (P = .043) and 58% versus 38% (P = .103), respectively. The overall cumulative incidence of nonrelapse mortality (NRM) was 29% in group 2. The cumulative incidence of NRM differed markedly between group 3 (16%; 95% confidence interval [CI], 4%-28%) and group 4 (44%, 95% CI, 34%-54%) (P = .013). We found no difference in cytomegalovirus (CMV) reactivation between groups 3 and 4. These results suggest that in mismatched uHSCT, a low dose of ATG (total 2.5 mg/kg) may prevent moderate to severe aGVHD, with comparable rates of relapse and CMV reactivation and a greatly decreased rate of NRM.

Treatment of BK virus-associated hemorrhagic cystitis in pediatric hematopoietic stem cell transplant recipients with cidofovir: a single-center experience

BK virus (BKV)‐associated hemorrhagic cystitis (BKV‐HC) is a severe complication after hematopoietic stem cell transplantation (HSCT). Cidofovir (CDV) has emerged as an effective agent for the treatment of BKV nephropathy, but its use for BKV‐HC in pediatric HSCT recipients has not yet been established as a standard therapy.

The Activating Killer Cell Immunoglobulin-Like Receptors as Important Determinants of Acute Graft-Versus Host Disease in Hematopoietic Stem Cell Transplantation for Acute Myelogenous Leukemia

Background. We investigated the influence of killer cell immunoglobulin-like receptor (KIR) genes, based on the genotypes of inhibitory or activating KIR, in stem cell recipients with acute myelogenous leukemia and their human leukocyte antigen-matched sibling donors on acute graft-versus host disease (GVHD) after hematopoietic stem cell transplantation. Methods. We studied 53 consecutive donor–recipient pairs to determine the impact of KIR genotypes and their bidirectional KIR interactions. Results. All activating KIR genes in donors were important factors for determining outcome in a manner distinctive for each gene studied. Specifically, the 2DS2 gene and the 2DS4*003 allele were closely correlated with acute GVHD. The 2DS1 gene was associated with a better long-term survival, even if present only in the donor and not the recipient. The 2DS3–2DS5 dual genes were more often involved in a variety of transplant-related complications. Conclusions. In conclusion, these factors may help predict transplant outcomes and aid in our understanding of immunogenetic specificity.

Long-term pattern of pleural effusion from chronic myeloid leukemia patients in second-line dasatinib therapy.

Dasatinib is a potent second-generation tyrosine kinase inhibitor approved for the treatment of chronic myeloid leukemia after imatinib failure. However, some patients treated with dasatinib experience pleural effusions (PEs). The determinants of pleural effusion in long-term dasatinib treatment (median 35 months, range 1–55) were investigated in single-center data of 65 patients enrolled in global phase 2 and phase 3 trials. Of the 65 patients, 35 (54%) developed dasatinib-induced pleural effusion (a median onset time, 20 months; range 0.2–54). The first pleural effusion developed in 15 (43%) patients within 12 months of dasatinib therapy. Disease phase (P = 0.02), dose schedule (P = 0.002) and actual daily mean dose (P = 0.0002) were significantly associated with an increased risk of pleural effusion. Twice-daily administration of dasatinib resulted in significantly more patients developing pleural effusions compared with the once-daily dosing schedule, particularly in advanced disease. In addition, a strong correlation was found between actual daily mean dose and time to onset of pleural effusions in patients treated with a daily mean dose >100 mg/day of dasatinib (P = 0.01). These data emphasize the need for dasatinib dose and schedule optimization and long-term monitoring of dasatinib-treated patients to prevent the negative clinical implications of pleural effusion.

Comparison of Allogeneic Stem Cell Transplantation from Familial-Mismatched/Haploidentical Donors and from Unrelated Donors in Adults with High-Risk Acute Myelogenous Leukemia

To weigh the pros and cons of familial-mismatched/haploidentical transplantation (FMT) in patients with high-risk acute myelogenous leukemia, we assessed outcomes of 23 patients who underwent FMT, using reduced-intensity conditioning with total body irradiation 800 cGy/busulfan/fludarabine/antithymocyte globulin without ex vivo T cell depletion, compared to 33 patients who underwent well-matched unrelated donor transplantation (WM-UDT) and 13 who underwent partially matched unrelated donor transplantation (PM-UDT) during the same period. The FMT patients had not only a similar pattern of engraftment and immune reconstitution as the WM-UDT and PM-UDT patients but also comparable incidences and severity of acute and chronic graft-versus-host disease. The FMT patients did not experience any form of engraftment failure. However, the cumulative incidence of cytomegalovirus DNAemia was significantly higher in the FMT group compared with the other groups (P = .036). After a median follow-up of 28 months, overall survival, disease-free survival, relapse, and nonrelapse mortality were 83%, 74%, 20%, and 7%, respectively, for WM-UDT; 51%, 51%, 31%, and 18% for PM-UDT; and 66%, 64%, 26%, and 10% for FMT. This demonstrates a trend for favorable survival outcomes of WM-UDT over FMT and of FMT over PM-UDT. However, we found no significant statistical differences in survival according to donor type. These data need to be interpreted cautiously because of limited power calculations due to the small number of each donor group. This pilot study suggests the feasibility of FMT using our novel regimen with careful evaluation of CMV DNAemia compared with WM-UDT and PM-UDT. Further trials with larger numbers of patients, comparing FMT directly with transplantation with other donor types, are needed.

A well-tolerated regimen of 800 cGy TBI-fludarabine-busulfan-ATG for reliable engraftment after unmanipulated haploidentical peripheral blood stem cell transplantation in adult patients with acute myeloid leukemia.

Eighty adult patients with acute myeloid leukemia (AML) received peripheral blood T cell-replete HLA haploidentical hematopoietic stem cell transplantation (haplo-HSCT). Disease status at transplantation was either first or second complete remission (CR, n = 69) or relapse/refractory (n = 11). Identical transplant-related procedures with conditioning regimen consisting of fractionated 800 cGy total body irradiation (TBI), fludarabine (30 mg/m(2)/day for 5 days), busulfan (3.2 mg/kg/day for 2 days), and antithymocyte globulin (1.25 mg/kg/day on days -4 to -1) and graft-versus-host disease (GVHD) prophylaxis with tacrolimus and methotrexate were used in all patients. Recovery of neutrophil (median, 11 days) and platelet (median, 10 days) counts was achieved in all patients with full donor chimerism (≥ 99%), and no delayed engraftment failure was observed. The cumulative incidence of grades III to IV acute GVHD and moderate to severe chronic GVHD was 11.2% and 26.3%, respectively. A donor CD8(+) and CD4(+) T cell dose above the median value was significantly associated with the incidences of grades II to IV acute GHVD and moderate to severe chronic GVHD, respectively. After a median follow-up of 28 months for survivors, the 2-year cumulative incidences of relapse (n = 20) and nonrelapse mortality (n = 10) were 26.6% and 12.2%, respectively. Although all but 1 patient in relapse/refractory status died, the 2-year overall and progression-free survival of patients in first CR was 82.5% and 75.1%, respectively. We suggest the strategy of fractionated 800 cGy TBI-based conditioning with unmanipulated peripheral blood stem cell grafts seems feasible with favorable outcomes for adult patients with AML undergoing haplo-HSCT in CR.

Comparable long-term outcomes after reduced-intensity conditioning versus myeloablative conditioning allogeneic stem cell transplantation for adult high-risk acute lymphoblastic leukemia in complete remission.

The role of reduced‐intensity conditioning (RIC) in adult acute lymphoblastic leukemia (ALL) remains unclear because of the small sample size, short follow‐up duration, various regimens for conditioning and graft‐versus‐host disease (GVHD) prophylaxis, and the heterogeneity of selection criteria for transplantation. We compared long‐term outcomes of 60 consecutive RIC transplants (fludarabine plus melphalan) with 120 myeloablative conditioning (MAC) transplants (total body irradiation plus cyclophosphamide) for adult high‐risk ALL in first or second complete remission. All transplants received a uniform strategy of pretransplant chemotherapy and GVHD prophylaxis. Compared to MAC transplants, RIC transplants had older age (46 years vs. 33 years, P < 0.001) and higher proportions of transplantation using peripheral blood (93.3% vs. 13.3%; P < 0.001) but otherwise showed similar characteristics. After a median follow‐up of 67 months, RIC transplants showed comparable nonrelapse mortality (21.2% vs. 24.3%) and disease‐free survival (50.8% vs. 54.9%) to MAC transplants, although relapse risk was higher (34.2% vs. 26.4%; HR, 2.07; P = 0.019) in multivariate analysis. Other independent factors associated with better outcomes were the presence of chronic GVHD and transplantation in first complete remission. Interestingly, the negative impact of RIC on relapse risk was seen only for Philadelphia‐positive ALL transplants (32.7% vs. 19.6%; HR, 3.46; P = 0.020), while no difference was found between RIC and MAC for Philadelphia‐negative ALL transplants (35.0% vs. 32.1%; HR, 1.39; P = 0.429). RIC can be considered as a reasonable choice for providing a sufficient long‐term graft‐versus‐leukemia effect for adult high‐risk ALL patients ineligible for MAC. Am. J. Hematol. 88:634–641, 2013.

Outcomes of elderly de novo acute myeloid leukemia treated by a risk‐adapted approach based on age, comorbidity, and performance status

Several criteria to define fitness for induction chemotherapy in elderly acute myeloid leukemia (AML) have been proposed; however, no studies have reported outcomes according to the application of a risk‐adapted approach. We treated 256 consecutive patients with elderly AML (≥60 years) with a risk‐adapted approach based on age, comorbidity score (CS), and performance status (ECOG). Eighty‐five low‐risk patients (age ≤ 65 years and ECOG 0–1 with CS < 2), 86 intermediate‐risk patients (age > 65 years or ECOG = 2 with CS < 2), and 85 high‐risk patients (ECOG > 2 or CS ≥ 2) were treated with induction chemotherapies, including standard intensive regimens, abbreviated‐scheduled regimens, and modified low‐dose cytarabine with oral etoposide (mLDAC), respectively. Overall response rates (ORR; complete response and complete response with incomplete recovery) for these three groups were 71.8%, 60.5%, and 41.2%, respectively, without a significant difference in early death rate (17.6%, 25.6%, 23.5%, P = 0.415). Among three abbreviated‐scheduled regimens, a gemtuzumab ozogamicin (GO)‐containing regimen (n = 43) showed a similar ORR rate (72.1%) to the intensive regimen. After achieving remission, 142 patients went on postremission treatments, including reduced‐intensity allogeneic transplantation (RIC, n = 41), standard consolidation (n = 71), and repeated mLDAC (n = 30) according to donor availability, age, ECOG, and CS. Multivariate analyses revealed that not only RIC, but also repeated mLDAC, resulted in significantly superior survival outcomes to standard consolidation independent of age, ECOG, and CS. Clinical benefits of mLDAC for high‐risk patients and abbreviated induction with GO for intermediate‐risk patients should be confirmed with further studies. Our results also suggest that RIC should be actively considered in elderly AML as a postremission treatment. Am. J. Hematol. 88:1074–1081, 2013.

Improvement in Hematopoiesis after Iron Chelation Therapy with Deferasirox in Patients with Aplastic Anemia

Iron overload due to regular transfusions of packed red cells can cause multiple organ damage. Iron chelation therapy (ICT) is important in patients with aplastic anemia (AA) who require blood transfusions as supportive management. With the introduction of the oral iron chelator deferasirox, ICT has become more widely available and feasible. We studied 4 adult AA patients who had transfusion-induced iron overload and showed hematological improvement after ICT with oral deferasirox. Following deferasirox treatment, hemoglobin increased and serum ferritin levels decreased, and the patients subsequently became transfusion independent. Our experience raises the possibility of the potential benefit of ICT on hematopoiesis. Further long-term studies in larger patient cohorts are needed to clarify the effect of the restoration of hematopoiesis after iron chelation therapy.