Comparative outcome of reduced intensity and myeloablative conditioning regimen in HLA identical sibling allogeneic haematopoietic stem cell transplantation for patients older than 50 years of age with acute myeloblastic leukaemia: a retrospective survey from the Acute Leukemia Working Party (ALWP) of the European group for Blood and Marrow Transplantation (EBMT)

Effects of T-Cell Depletion on Allogeneic Hematopoietic Stem Cell Transplantation Outcomes in AML Patients

Graft versus host disease (GVHD) remains one of the leading causes of morbidity and mortality associated with conventional allogeneic hematopoietic stem cell transplantation (HCT). The use of T-cell depletion significantly reduces this complication. Recent prospective and retrospective data suggest that, in patients with AML in first complete remission, CD34+ selected grafts afford overall and relapse-free survival comparable to those observed in recipients of conventional grafts, while significantly decreasing GVHD. In addition, CD34+ selected grafts allow older patients, and those with medical comorbidities or with only HLA-mismatched donors to successfully undergo transplantation. Prospective data are needed to further define which groups of patients with AML are most likely to benefit from CD34+ selected grafts. Here we review the history of T-cell depletion in AML, and techniques used. We then summarize the contemporary literature using CD34+ selection in recipients of matched or partially mismatched donors (7/8 or 8/8 HLA-matched), and provide a summary of the risks and benefits of using T-cell depletion.

Total Body Irradiation-Based Myeloablative Haploidentical Stem Cell Transplantation Is a Safe and Effective Alternative to Unrelated Donor Transplantation in Patients Without Matched Sibling Donors

We enrolled 30 patients on a prospective phase II trial utilizing a total body irradiation (TBI)-based myeloablative preparative regimen (fludarabine 30 mg/m2/day × 3 days and TBI 150 cGy twice per day on day -4 to -1 [total dose 1200 cGy]) followed by infusion of unmanipulated peripheral blood stem cells from a haploidentical family donor (haplo). Postgrafting immunosuppression consisted of cyclophosphamide 50 mg/kg/day on days 3 and 4, mycophenolate mofetil through day 35, and tacrolimus through day 180. Median patient age was 46.5 years (range, 24 to 60). Transplantation diagnosis included acute myelogenous leukemia (n = 16), acute lymphoblastic leukemia (n = 6), chronic myelogenous leukemia (n = 5), myelodysplastic syndrome (n = 1), and non-Hodgkin's lymphoma (n = 2). Using the Dana Farber/Center for International Blood and Marrow Transplant Research/Disease Risk Index (DRI), patients were classified as low (n = 4), intermediate (n = 12), high (n = 11), and very high (n = 3) risk. All patients engrafted with a median time to neutrophil and platelet recovery of 16 and 25 days, respectively. All evaluable patients achieved sustained complete donor T cell and myeloid chimerism by day +30. Acute graft-versus-host disease (GVHD) grades II to IV and III and IV was seen in 43% and 23%, respectively. The cumulative incidence of chronic GVHD was 56% (severe in 10%). After a median follow-up of 24 months, the estimated 2-year overall survival (OS), disease-free survival (DFS), nonrelapse mortality, and relapse rate were 78%, 73%, 3%, and 24%, respectively. Two-year DFS and relapse rate in patients with low/intermediate risk disease was 100% and 0%, respectively, compared with 39% and 53% for patients with high/very high risk disease. When compared with a contemporaneously treated cohort of patients at our institution receiving myeloablative HLA-matched unrelated donor (MUD) transplantation (acute myelogenous leukemia [n = 17], acute lymphoblastic leukemia [n = 15], chronic myelogenous leukemia [n = 7], myelodysplastic syndrome [n = 7], non-Hodgkin lymphoma [n = 1], chronic lymphoblastic leukemia [n = 1]), outcomes were statistically similar, with 2-yr OS and DFS being 78% and 73%, respectively after haplo transplantation versus 71% and 64%, respectively, after MUD transplantation. In patients with DRI low/intermediate risk disease, 2-yr DFS was superior after haplo compared with MUD transplantations (100% versus 74%, P = .032), whereas there was no difference in DFS in patients with high/very high risk disease (39% versus 37% for haplo and MUD respectively, P = .821). Grade II to IV acute GVHD was seen less often after haplo compared with MUD transplantation (43% versus 63%, P = .049), as was moderate-to-severe chronic GVHD (22% versus 58%, P = .003). Myeloablative haplo transplantation using this regimen is a valid option for patients with advanced hematologic malignancies who lack timely access to a conventional donor. Outcomes appear at least equivalent to those seen in contemporaneous patients who underwent transplantation from MUD.

Reduced-intensity conditioned allogeneic SCT in adults with AML

AML is currently the most common indication for reduced-intensity conditioned (RIC) allo-SCT. Reduced-intensity regimens allow a potent GVL response to occur with minimized treatment-related toxicity in patients of older age or with comorbidities that preclude the use of myeloablative conditioning. Whether RIC SCT is appropriate for younger and more standard risk patients is not well defined and the field is changing rapidly; a prospective randomized trial of myeloablative vs RIC (BMT-CTN 0901) was recently closed when early results indicated better outcomes for myeloablative regimens. However, detailed results are not available, and all patients in that study were eligible for myeloablative conditioning. RIC transplants will likely remain the standard of care as many patients with AML are not eligible for myeloablative conditioning. Recent publication of mature results from retrospective and prospective cohorts provide contemporary efficacy and toxicity data for these attenuated regimens. In addition, recent studies explore the use of alternative donors, introduce regimens that attempt to reduce toxicity without reducing intensity, and identify predictive factors that pave the way to personalized approaches. These studies paint a picture of the future of RIC transplants. Here we review the current status of RIC allogeneic SCT in AML.

Increasing incidence of chronic graft-versus-host disease in allogeneic transplantation: a report from the Center for International Blood and Marrow Transplant Research

Although transplant practices have changed over the last decades, no information is available on trends in incidence and outcome of chronic graft-versus-host disease (cGVHD) over time. This study used the central database of the Center for International Blood and Marrow Transplant Research (CIBMTR) to describe time trends for cGVHD incidence, nonrelapse mortality, and risk factors for cGVHD. The 12-year period was divided into 3 intervals, 1995 to 1999, 2000 to 2003, and 2004 to 2007, and included 26,563 patients with acute leukemia, chronic myeloid leukemia, and myelodysplastic syndrome. Multivariate analysis showed an increased incidence of cGVHD in more recent years (odds ratio = 1.19, P < .0001), and this trend was still seen when adjusting for donor type, graft type, or conditioning intensity. In patients with cGVHD, nonrelapse mortality has decreased over time, but at 5 years there were no significant differences among different time periods. Risk factors for cGVHD were in line with previous studies. This is the first comprehensive characterization of the trends in cGVHD incidence and underscores the mounting need for addressing this major late complication of transplantation in future research.

Allogeneic hematopoietic cell transplantation outcomes in acute myeloid leukemia: similar outcomes regardless of donor type

The use of alternative donor transplants is increasing as the transplantation-eligible population ages and sibling donors are less available. We evaluated the impact of donor source on transplantation outcomes for adults with acute myeloid leukemia undergoing myeloablative (MA) or reduced-intensity conditioning (RIC) transplantation. Between January 2000 and December 2010, 414 consecutive adult patients with acute myeloid leukemia in remission received MA or RIC allogeneic transplantation from either a matched related donor (n = 187), unrelated donor (n = 76), or umbilical cord blood donor (n = 151) at the University of Minnesota or Hôpital St. Louis in Paris. We noted similar 6-year overall survival across donor types: matched related donor, 47% (95% confidence interval [CI], 39% to 54%); umbilical cord blood, 36% (95% CI, 28% to 44%); matched unrelated donor, 54% (95% CI, 40% to 66%); and mismatched unrelated donor, 51% (95% CI, 28% to 70%) (P < .11). Survival differed based on conditioning intensity and age, with 6-year survival of 57% (95% CI, 47% to 65%), 39% (95% CI, 28% to 49%), 23% (95% CI, 6% to 47%), 47% (95% CI, 36% to 57%), and 28% (95% CI, 17% to 41%) for MA age 18 to 39, MA age 40+, or RIC ages 18 to 39, 40 to 56, and 57 to 74, respectively (P < .01). Relapse was increased with RIC and lowest in younger patients receiving MA conditioning (hazard ratio, 1.0 versus 2.5 or above for all RIC age cohorts), P < .01. Transplantation-related mortality was similar across donor types. In summary, our data support the use of alternative donors as a graft source with MA or RIC for patients with acute myeloid leukemia when a sibling donor is unavailable.

Cyclophosphamide/fludarabine nonmyeloablative allotransplant for acute myeloid leukemia

We compared survival outcomes following myeloablative allotransplant (MAT) or cyclophosphamide/fludarabine (Cy/Flu) nonmyeloablative allotransplant (NMAT) for 165 patients with acute myelogenous leukemia (AML) in remission or without frank relapse. Patients who received NMAT were more likely to be older and have secondary AML and lower performance status. At a median follow-up of 61 months, median event-free survival and overall survival survival were not different between NMAT and MAT in univariate as well as multivariate analyses. Cy/Flu NMAT may provide similar disease control and survival when compared with MAT in patients with AML in remission or without frank relapse.

Decreased nonrelapse mortality after unrelated cord blood transplantation for acute myeloid leukemia using reduced-intensity conditioning: a prospective phase II multicenter trial

A prospective phase II multicenter trial was performed with the aim to obtain less than 25% nonrelapse mortality (NRM) after unrelated cord blood transplantation (UCBT) for adults with acute myeloid leukemia (AML) using a reduced-intensity conditioning regimen (RIC) consisting of total body irradiation (2 Gy), cyclophosphamide (50 mg/kg), and fludarabine (200 mg/m(2)). From 2007 to 2009, 79 UCBT recipients were enrolled. Patients who underwent transplantation in first complete remission (CR1) (n = 48) had a higher frequency of unfavorable cytogenetics and secondary AML and required more induction courses of chemotherapy to achieve CR1 compared with the others. The median infused total nucleated cells (TNC) was 3.4 × 10(7)/kg, 60% received double UCBT, 77% were HLA mismatched (4/6), and 40% had major ABO incompatibility. Cumulative incidence of neutrophil recovery at day 60 was 87% and the cumulative incidence of 100-day acute graft-versus-host disease (II to IV) was 50%. At 2 years, the cumulative incidence of NRM and relapse was 20% and 46%, respectively. In multivariate analysis, major ABO incompatibility (P = .001) and TNC (<3.4 × 10(7)/kg; P = .001) were associated with increased NRM, and use of 2 or more induction courses to obtain CR1 was associated with increased relapse incidence (P = .04). Leukemia-free survival (LFS) at 2 years was 35%, and the only factor associated with decreased LFS was secondary AML (P = .04). In conclusion, despite the decreased NRM observed, other RIC regimens with higher myelosuppression should be evaluated to decrease relapse in high-risk AML. (EUDRACT 2006-005901-67).

Successful early unmanipulated haploidentical transplantation with reduced-intensity conditioning for primary graft failure after cord blood transplantation in hematologic malignancy patients

Primary graft failure (pGF) is a frequent complication following cord blood transplantation (CBT). For those patients who will not experience autologous recovery, salvage transplantation should be performed as early as possible. However, standardized treatment protocols for pGF, such as the optimal stem cell source, preparative regimen and the ideal time for salvage transplantation, have yet to be determined. Therefore, we analyzed 17 hematologic malignancy patients who received unmanipulated haploidentical peripheral blood (PB) and BM transplantation with reduced-intensity conditioning (RIC) as a salvage therapy for pGF after CBT. The median interval between the two transplantations was 38 days. The RIC regimen for salvage transplantation consisted of fludarabine, antithymocyte globulin, CY and low-dose TBI. The neutrophil and plt engraftments were achieved in 14 (82.4%) and 13 (76.4%) patients, respectively. The cumulative incidences of grades II-IV and grades III-IV aGVHD were 35.3% and 17.6%, respectively. The cumulative incidence of chronic GVHD was 29.4%. After a median follow-up of 43 months, 10 of 17 patients remained alive in CR. The cumulative incidence of TRM at 180 days was 29.4%. The probability of 3-year OS and leukemia-free survival was 57.5%. Our results show that unmanipulated haploidentical PB and BM transplantation under a RIC regimen is an effective treatment for pGF after CBT.

Comparison of umbilical cord blood allogeneic stem cell transplantation vs. auto-SCT for adult acute myeloid leukemia patients in second complete remission at transplant: a retrospective study on behalf of the SFGM-TC

This retrospective study considered the outcomes of 181 patients with acute myeloid leukemia (AML) transplanted in second complete remission (CR2) between January 2005 and April 2012 and who received either a myeloablative autologous stem cell transplant (Auto-SCT; n = 82; median age: 48 years; median follow-up: 45 months) or an umbilical cord blood (UCB) allogeneic SCT (n = 99, median age: 46 years; median follow-up: 36 months; conditioning regimens: myeloablative n = 21, reduced n = 78; single unit n = 37, double units n = 62). Although the Auto group showed a significant better prognostic profile at transplant, with longer median interval between diagnosis and time of graft, higher incidence of good-risk cytogenetics and lower number of previously transplanted patients, 3-year OS and LFS were similar between both groups (Auto: 59 ± 6% vs. 50 ± 6%, P = 0.45; and 57 ± 6% vs. 46 ± 6%, P = 0.37). In multivariate analysis, UCB allo-SCT was associated with lower relapse incidence (HR: 0.3, 95% CI: 0.11-0.82, P = 0.02), but higher non-relapse mortality (NRM) (HR: 4.16; 95% CI: 1.46-11.9, P = 0.008). Results from this large study suggest that UCB allo-SCT provides better disease control than auto-SCT, which is especially important in the setting of high-risk disease. However, this disease control advantage is counterbalanced by higher toxicity, highlighting the need for novel approaches aiming to decrease NRM after UCB allo-SCT.

Impact of early remission by induction therapy on allogeneic stem cell transplantation for acute myeloid leukemia with an intermediate-risk karyotype in first complete remission

For patients with acute myeloid leukemia (AML) early achievement of remission during induction treatment is an important predictor for long-term outcome irrespective of the type of consolidation therapy employed. Here, we retrospectively examined the prognostic impact of early remission (ER) vs. delayed remission (DR) in a cohort of 132 AML patients with an intermediate-risk karyotype undergoing allogeneic stem cell transplantation (alloSCT) in first complete remission (CR1). In contrast to patients showing DR, patients achieving ER had a significantly higher 3-yr overall survival (OS) and disease-free survival (DFS) of 76% vs. 54% (P = 0.03) and 76% vs. 53% (P = 0.03). Likewise, 3 yr after alloSCT the cumulative incidence of relapse (CI-R) was significantly lower in the ER subgroup as compared to patients achieving DR, that is, 10% vs. 35% (P = 0.004), whereas non-relapse mortality (NRM) did not differ significantly. Multivariate analysis identified DR as an independent prognosticator for an inferior DFS (HR 3.37, P = 0.002) and a higher CI-R (HR 3.55, P = 0.002). Taken together, these data may indicate that the rapid achievement of remission predicts a favorable outcome in patients with intermediate-risk AML undergoing alloSCT in CR1. In turn, the adverse effect of DR may not be fully overcome by alloSCT.

[Current indications of allogeneic stem cell transplant in adults with acute myeloid leukemia]

Allogeneic stem cell transplantation (SCT) is an increasingly important therapeutic option for the treatment of adult patients with acute myeloid leukemia. Here we review the current indications of SCT in this disease. While patients with favorable cytogenetics should receive consolidation chemotherapy, patients with unfavorable karyotype are prime candidates for SCT or new approaches to SCT (which should be done in first complete remission). Patients with intermediate prognoses should also receive SCT in first complete remission. In the absence of a suitable matched related donor, most patients will be able to find an alternative donor to proceed to a potentially curative allogeneic transplantation. The use of reduced-intensity conditioning regimens before SCT has allowed patients in the sixth or seventh decades of life to be routinely transplanted. Despite major differences among transplant centers in the intensity and composition of the conditioning regimen and immunosuppression, choice of graft source, postgraft immune-modulation, and supportive care, there has been a dramatic improvement in terms of tolerance. Although it is presumed to be a curative strategy, major complications of SCT remain graft-versus-host disease, delayed immune recovery, multiple comorbidities, and relapse after transplant.

Similar transplantation outcomes for acute myeloid leukemia and myelodysplastic syndrome patients with haploidentical versus 10/10 human leukocyte antigen-matched unrelated and related donors

Allogeneic stem cell transplantation for patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) has been performed primarily with an HLA-matched donor. Outcomes of haploidentical transplantation have recently improved, and a comparison between donor sources in a uniform cohort of patients has not been performed. We evaluated outcomes of 227 patients with AML/MDS treated with melphalan-based conditioning. Donors were matched related (MRD) (n = 87, 38%), matched unrelated (MUD) (n = 108, 48%), or haploidentical (n = 32, 14%). No significant differences were found between haploidentical and MUD transplantation outcomes; however, there was a trend for improved outcomes in the MRD group, with 3-year progression-free survival for patients in remission of 57%, 45%, and 41% for MRD, MUD, and haploidentical recipients, respectively (P = .417). Recovery of T cell subsets was similar for all groups. These results suggest that haploidentical donors can safely extend transplantation for AML/MDS patients without an HLA-matched donor. Prospective studies comparing haploidentical and MUD transplantation are warranted.

Equivalent outcomes using reduced intensity or conventional myeloablative conditioning transplantation for patients aged 35 years and over with AML

Allogeneic hematopoietic stem cell transplantation provides the best chance of long-term survival for patients with AML, but is associated with an unpredictable risk of treatment-related mortality. From January 2000 to December 2010, we compared the outcomes for patients with AML aged 35 and over using reduced-intensity conditioning (RIC, N=60) or conventional myeloablative conditioning (MAC) regimen (N=72) transplantation. The median follow-up was 47 months (10-134). The 4-year cumulative incidence of non-relapse mortality was 21%. After adjusting for cytogenetic risk, gender donor/recipient mismatch and CD34+ cells, non-relapse mortality was significantly lower with the RIC regimen (P=0.027). The 4-year cumulative incidence of relapse was 38% and no difference was observed in the adjusted relapse rate between the two groups. The 4-year OS rate was 46%. Using both Cox regression and inverse probability-of-treatment weighted (IPTW) method, a similar OS rate was found with both regimens (adjusted hazard ratios for conventional vs reduced of 1.14 (95% CI 0.67-1.93, P=0.64) with Cox regression, and 1.14 (95% CI 0.55-2.34, P=0.73) with IPTW). Until prospective trials are completed, this study supports the use of a reduced-intensity regimen prior to transplantation for patients with AML aged 35 and over.

Comparison of reduced-intensity and myeloablative conditioning regimens for allogeneic hematopoietic stem cell transplantation in patients with acute myeloid leukemia and acute lymphoblastic leukemia: a meta-analysis

Currently, the indications to perform reduced-intensity conditioning allogeneic hematopoietic stem cell transplant (RIC-HCT) are based on data derived mainly from large registry and single-centre retrospective studies. Thus, at the present time, there is limited direct evidence supporting the current practice in selecting patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) for RIC versus myeloablative conditioning (MAC) transplants. To determine the relationship between dose intensity of conditioning regimen and survival outcomes after allografting in AML/ALL patients, we performed a meta-analysis of 23 clinical trials reported between 1990 and 2013 involving 15,258 adult patients that compare survival outcomes after RIC-HCT versus MAC-HCT. RIC-HCT resulted in comparable <2-year and 2-6 year overall survival (OS) rates post-transplantation even though the RIC-HCT recipients were older and had more active disease than MAC-HCT recipients. The 2-6 year progression-free survival (PFS), nonrelapse mortality, acute graft-versus-host disease (GvHD) and chronic GvHD rates were reduced after RIC-HCT, but relapse rate was increased. Similar outcomes were observed regardless of disease type and status at transplantation. Odds ratio for all outcomes remained comparable with or without performing separate analyses for the year of HCT and for retrospective versus prospective studies. Among RIC-HCT recipients, survival rates were superior if patients were in CR at transplantation. Significant inter-study heterogeneity for aGvHD data and publication bias for PFS data were observed. This meta-analysis showed no OS benefit of MAC-HCT over RIC-HCT across the entire cohort of patients suggesting that RIC-HCT could be an effective therapeutic option for AML/ALL patients who are ineligible for MAC-HCT and CR status is preferred before RIC-HCT.

Allogeneic hematopoietic cell transplantation for acute myeloid leukemia during first complete remission: a clinical perspective

Allogeneic hematopoietic cell transplantation (HCT) is the most potent therapy for preventing relapse of acute myeloid leukemia (AML). Although its efficacy is compromised by a high risk of treatment-related morbidity and mortality, an accumulating body of evidence has led to the general recommendation favoring allogeneic HCT from a matched sibling donor during first complete remission (CR1) for younger patients with cytogenetically intermediate- or high-risk AML. Over the past few decades, this field has seen a great many advancements. The indications for allogeneic HCT have been refined by taking into account the molecular profiles of leukemic cells and the degree of comorbidities. The introduction of high-resolution human leukocyte antigen-typing technology and advances in immunosuppressive therapy and supportive care measures have improved outcomes in alternative donor transplantation, while the parallel growth of unrelated donor registries and greater use of umbilical cord blood and haploidentical donors have considerably improved the chance of finding an alternative donor. The development of reduced-intensity and non-myeloablative conditioning has made it possible to receive allogeneic HCT for patients who might once have been considered ineligible due to advanced age or comorbidities. Thanks to these advances, the role of allogeneic HCT during CR1 has become progressively more important in the treatment of AML.

Results from a clofarabine-busulfan-containing, reduced-toxicity conditioning regimen prior to allogeneic stem cell transplantation: the phase 2 prospective CLORIC trial

We prospectively evaluated the safety and efficacy of a clofarabine, intravenous busulfan and antithymocyte globulin-based reduced-toxicity conditioning (CloB2A2) regimen before allogeneic stem cell transplantation. Thirty high-risk patients (median age: 59 years; acute myeloid leukemia n=11, acute lymphoblastic leukemia n=13; myelodysplastic syndrome n=5, bi-phenotypic leukemia n=1) were included in this phase 2 study. At time of their transplant, 20 and seven patients were in first and second complete remission, respectively, while three patients with myelodysplastic syndrome were responding to chemotherapy or who had not been previously treated. The CloB2A2 regimen consisted of clofarabine 30 mg/m(2)/day for 4 days, busulfan 3.2 mg/kg/day for 2 days and antithymocyte globulin 2.5 mg/kg/day for 2 days. The median follow-up was 23 months. Engraftment occurred in all patients. The 1-year overall survival, leukemia-free survival, relapse incidence and non-relapse mortality rates were 63±9%, 57±9%, 40±9%, and 3.3±3%, respectively. Comparing patients with acute myeloid leukemia/myelodysplastic syndrome versus those with acute lymphoblastic leukemia/bi-phenotypic leukemia, the 1-year overall and leukemia-free survival rates were 75±10% versus 50±13%, respectively (P=0.07) and 69±12% versus 43±13%, respectively (P=0.08), while the 1-year relapse incidence was 25±11% versus 57±14%, respectively (P=0.05). The CloB2A2 regimen prior to allogeneic stem cell transplantation is feasible, allowing for full engraftment and low toxicity. Disease control appears to be satisfactory, especially in patients with acute myeloid leukemia/myelodysplastic syndrome. The trial was registered at www.clinicaltrials.gov no. NCT00863148.

Allogeneic hematopoietic stem cell transplant for hematological malignancies from mismatched 9/10 human leukocyte antigen unrelated donors: comparison with transplants from 10/10 unrelated donors and human leukocyte antigen identical siblings

We studied the outcome of 213 patients who received allo-HSCT for hematological malignancies, 121 (57%) from HLA identical siblings, 63 (29%) from 10/10 HLA identical unrelated donors and 29 (14%) from 9/10 HLA mismatched unrelated donors. Engraftment was lower in the 9/10 HLA group (90%) than in the 10/10 HLA group (95%) than in the sibling group (99%); 3 months CI of aGVHD ≥ 2 was 32% (23-41), 20% (15-26) and 27% (23-32) respectively; the one year CI of extensive cGVHD was 21% (13-30), 9% (5-13) and 17% (14-21) respectively. The median OS was 10 months (5-21), 18 months (11-NR) and 60 months (31-NR) respectively with 2-years probability of 19% (8-44), 43% (31-59) and 63% (54-74) respectively. TRM was significantly higher in the 9/10 HLA group with 1 year CI of 45% (35-55), compared to 33% (27-39) in the unrelated 10/10 HLA group and 12% (9-15) in the identical siblings group (p < 0.001).

Reduced-toxicity conditioning prior to allogeneic stem cell transplantation improves outcome in patients with myeloid malignancies

The introduction of reduced intensity/toxicity conditioning regimens has allowed allogeneic hematopoietic cell transplantation to be performed in patients who were previously considered too old or otherwise unfit. Although it led to a reduction in non-relapse mortality, disease control remains a major challenge. We studied the outcome of 165 patients with acute myeloid leukemia (n=124) or myelodysplastic syndrome (n=41) transplanted after conditioning with fludarabine (30 mg/m(2)/day for 5 days), intravenous busulfan (either 260 mg/m(2): reduced intensity conditioning, or 390-520 mg/m(2): reduced toxicity conditioning), and rabbit anti-thymoglobulin (2.5 mg/kg/day for 2 days). The median age of the patients at transplantation was 56.8 years. The 2-year relapse incidence was 29% (23% versus 39% for patients transplanted in first complete remission and those transplanted beyond first complete remission, respectively; P=0.008). The 2-year progression-free survival rate was 57% (95% CI: 49.9-65). It was higher in the groups with favorable or intermediate cytogenetics than in the group with unfavorable cytogenetics (72.7%, 60.5%, and 45.7%, respectively; P=0.03). The cumulative incidence of grades 2-4 and 3-4 acute graft-versus-host disease at day 100 was 19.3% and 7.9%, respectively. The cumulative incidence of chronic graft-versus-host disease at 1 year was 21.6% (severe forms: 7.8%). Non-relapse mortality at 1 year reached 11%. The 2-year overall survival rate was 61.8% (95% CI: 54.8-69.7). Unfavorable karyotype and disease status beyond first complete remission were associated with a poorer survival. This well-tolerated conditioning platform can lead to long-term disease control and offers possibilities of modulation according to disease stage or further development.

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

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

Comparing i.v. BU dose intensity between two regimens (FB2 vs FB4) for allogeneic HCT for AML in CR1: a report from the Acute Leukemia Working Party of EBMT

This retrospective analysis compared two regimens of fludarabine combined with i.v. BU 6.4 mg/kg (FB2) or BU 12.8 mg/kg (FB4) for allografting of AML in first CR. A total of 437 patients (median age: 50 years) were administered FB2 (n = 225, 51%) or FB4 (n = 212, 49%). Median follow-up time was 28 months. Use of FB2 resulted in a longer time to neutrophil engraftment (17 vs 15 days, P < 0.0001) but no difference in incidence of grade II-IV acute (P = 0.54) or chronic GVHD (P = 0.51). In patients < 50 years of age, FB2 was associated with a higher 2-year cumulative incidence of relapse (33 ± 6% vs 20 ± 4%, P = 0.04), but there was no difference in 2-year leukemia-free survival (LFS) (P = 0.45), OS (P = 0.53) or non-relapse mortality (P = 0.17). In recipients ⩾ 50 years of age, FB2 resulted in better 2-year LFS (63 ± 4% vs 42 ± 7%, P = 0.02) and OS (68 ± 4% vs 45 ± 7%, P = 0.006); a lower 2-year non-relapse mortality, albeit not statistically significant (15 ± 3% vs 29 ± 6%, P = 0.06), was observed with FB2. FB2 is an effective and well-tolerated regimen in patients ⩾ 50 years of age and does not compromise survival when used in patients <50 years undergoing allogeneic transplantation for AML in first CR.

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

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

Allogeneic hematopoietic cell transplant for acute myeloid leukemia: Current state in 2013 and future directions

Acute myeloid leukemia (AML) represents a heterogeneous group of high-grade myeloid neoplasms of the elderly with variable outcomes. Though remission-induction is an important first step in the management of AML, additional treatment strategies are essential to ensure long-term disease-free survival. Recent pivotal advances in understanding the genetics and molecular biology of AML have allowed for a risk-adapted approach in its management based on relapse-risk. Allogeneic hematopoietic cell transplantation (allo-HCT) represents an effective therapeutic strategy in AML providing the possibility of cure with potent graft-versus-leukemia reactions, with a demonstrable survival advantage in younger patients with intermediate- or poor-risk cytogenetics. Herein we review the published data regarding the role of allo-HCT in adults with AML. We searched MEDLINE/PubMed and EMBASE/Ovid. In addition, we searched reference lists of relevant articles, conference proceedings and ongoing trial databases. We discuss the role of allo-HCT in AML patients stratified by cytogenetic- and molecular-risk in first complete remission, as well as allo-HCT as an option in relapsed/refractory AML. Besides the conventional sibling and unrelated donor allografts, we review the available data and recent advances for alternative donor sources such as haploidentical grafts and umbilical cord blood. We also discuss conditioning regimens, including reduced intensity conditioning which has broadened the applicability of allo-HCT. Finally we explore recent advances and future possibilities and directions of allo-HCT in AML. Practical therapeutic recommendations have been made where possible based on available data and expert opinion.

Siglec-G-CD24 axis controls the severity of graft-versus-host disease in mice

Activation of sialic-acid-binding immunoglobulin-like lectin-G (Siglec-G) by noninfectious damage-associated molecular patterns controls innate immune responses. However, whether it also regulates T-cell-mediated adaptive immune responses is not known. Graft-versus-host reaction is a robust adaptive immune response caused by allogeneic hematopoietic cell transplantation that have been activated by antigen-presenting cells (APCs) in the context of damaged host tissues following allogeneic hematopoietic cell transplantation. The role of infectious and noninfectious pattern recognition receptor-mediated activation in the induction and aggravation of graft-versus-host disease (GVHD) is being increasingly appreciated. But the role of pathways that control innate immune responses to noninfectious stimuli in modulating GVHD has heretofore not been recognized. We report that Siglec-G expression on host APCs, specifically on hematopoietic cells, negatively regulates GVHD in multiple clinically relevant murine models. Mechanistic studies with various relevant Siglec-G and CD24 knockout mice and chimeric animals, along with rescue experiments with novel CD24 fusion protein demonstrate that enhancing the interaction between Siglec-G on host APCs with CD24 on donor T cells attenuates GVHD. Taken together, our data demonstrate that Siglec-G-CD24 axis, controls the severity of GVHD and suggest that enhancing this interaction may represent a novel strategy for mitigating GVHD.

Alternative donor transplantation for older patients with acute myeloid leukemia in first complete remission: a center for international blood and marrow transplant research-eurocord analysis

We studied patients with acute myeloid leukemia (AML) over age 50 and in first complete remission (CR1) after adult unrelated donor (URD) (n = 441, 8/8 HLA matched; n = 94, 7/8 HLA matched) or umbilical cord blood (UCB; n = 205) transplantations. UCB recipients achieved CR1 within 8 weeks less often, and received reduced-intensity conditioning and cyclosporine-based graft-versus-host disease (GVHD) prophylaxis more often. Neutrophil recovery was slower in UCB (69% by day 28) compared with 8/8 HLA-matched URD (97%) and 7/8 HLA-matched (91%) (P < .001) recipients. Three-year transplantation-related mortality (TRM) was higher and leukemia-free survival (LFS) lower with UCB (35% and 28%, respectively) versus 8/8 HLA-matched URD (27% and 39%, respectively). TRM was higher in 7/8 HLA-matched URD (41%, P = .01), but LFS was similar at 34% (P = .39). Three-year chronic GVHD was the lowest in UCB (28%) versus 53% and 59% in 8/8 and 7/8 HLA-matched URD recipients, respectively. Three-year survival was 43% in 8/8 HLA-matched URD (95% confidence interval [CI], 38% to 48%), 30% in UCB (95% CI, 23% to 37%) (P = .002) and 37% in 7/8 URD (95% CI, 27 to 46). Allotransplantation for AML in CR1 with any of these grafts extends LFS for over one third of older patients. In the absence of an 8/8 HLA-matched URD or when transplantation is needed urgently, UCB can provide extended survival. Less frequent chronic GVHD with UCB transplantation may be of particular value for older patients.

Impact of postremission consolidation chemotherapy on outcome after reduced-intensity conditioning allogeneic stem cell transplantation for patients with acute myeloid leukemia in first complete remission: a report from the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation

BACKGROUND

The objective of the current study was to investigate the role of postremission consolidation chemotherapy before reduced-intensity conditioning (RIC) allogeneic stem cell transplantation (alloSCT) for patients with acute myeloid leukemia (AML) in first complete remission (CR1).

METHODS

Of the 789 consecutive patients with AML in CR1 who underwent RIC alloSCT from a human leukocyte antigen-matched sibling or matched unrelated donor peripheral stem cell grafts between 2001 and 2010, 591 patients received at least 1 cycle of consolidation chemotherapy and 198 patients did not receive any consolidation chemotherapy before alloSCT. To minimize inherent survival bias in favor of patients who underwent transplant long after achieving CR1, the study focused on 373 patients who underwent transplant within the median time frame between achievement of CR1 and alloSCT (3 months for patients who underwent alloSCT from matched siblings and 4 months for patients who underwent alloSCT from matched unrelated donors). In this subgroup, 151 patients did not receive any consolidation chemotherapy and 222 patients received ≥ 1 consolidation chemotherapy cycle.

RESULTS

With a median follow-up of 36 months (range, 2 months-135 months), the 3-year cumulative recurrence incidence (RI) was not significantly different between the groups (36% ± 4% for the group treated without consolidation chemotherapy vs 38% ± 3% for patients who received consolidation chemotherapy; P = .89). In addition, leukemia-free survival was similar between the groups (45% ± 4% and 47% ± 3%, respectively; P = .41). Dose intensity of cytarabine given during consolidation chemotherapy appeared to have no influence on RI. On multivariate analysis, pretransplant consolidation (≥ 1 cycle vs 0 cycles) was found to have no significant impact on RI (hazards ratio, 1.29; 95% confidence interval, 0.84-1.97 [P = .24]) or leukemia-free survival (hazards ratio, 1.00; 95% confidence interval, 0.71-1.42 [P = .99]).

CONCLUSIONS

The data from the current study suggest no apparent advantage for postremission consolidation chemotherapy before RIC alloSCT, provided a donor is readily available.

Cytogenetic risk grouping by the monosomal karyotype classification is superior in predicting the outcome of acute myeloid leukemia undergoing allogeneic stem cell transplantation in complete remission

We retrospectively analyzed the impact of cytogenetic abnormalities grouped according to the monosomal karyotype (MK) classification or the Southwest Oncology/Eastern Cooperative Oncology Group (SWOG/ECOG) definition in 263 patients with acute myeloid leukemia (AML) who underwent allogeneic stem cell transplantation (alloSCT) in complete remission (CR) at our center. Risk grouping using the MK criteria shows a highly significant difference in 5-yr overall survival (OS) ranging between 67%, for the most favorable, and 32%, for the poorest risk group (P = 0.001). Although similarly precise in predicting OS, the MK scheme better separates patients with respect to relapse incidence as compared to the SWOG/ECOG grouping (P = 0.0001 vs. P = 0.01). Notably, patients displaying non-MK abnormalities (MK-) had a 5-yr relapse incidence identical to those cytogenetically normal (CN), that is 24%. Multivariate analysis revealed that the MK classification is an independent prognosticator and superior in predicting OS (hazard ratios, HR 3.74, P = 0.01) and relapse incidence (HR 3.74, P = 0.005) as compared to the SWOG/ECOG criteria. Finally, subgroup analysis revealed that the prognostic capacity of the MK classification is highly significant in patients treated with standard myeloablative conditioning prior to alloSCT (P = 0.0011 for OS, P = 0.0007 for relapse). In contrast, the MK grouping failed to predict OS or relapse incidence in patients treated with reduced intensity conditioning. Taken together, these results indicate that the MK classification is superior in predicting the overall outcome of patients with AML undergoing alloSCT in CR. Furthermore, our data suggest that the genetic risk profile of MK- and CN patients is mostly overlapping in this setting.

The role of hypomethylating agents in the treatment of elderly patients with AML

There is a major unmet medical need for treatment options in elderly patients with acute myeloid leukemia (AML) who are deemed ineligible for intensive treatment. The recent approval of decitabine in the European Union for the treatment of patients with AML≥ 65 years old highlights the potential for hypomethylating agents in this setting. Here, we review evidence to support the use of hypomethylating agents in elderly patients and emphasize the importance of tolerability and quality of life considerations. We focus on the rationale for the continued clinical development of the ribonucleoside analog azacitidine in this setting. We discuss potential differences in the activity of azacitidine and decitabine in different patient subgroups that could possibly be explained by important differences in mechanism of action. Finally, we assess practical challenges that will be faced when integrating hypomethylating agents into clinical practice, such as how to define ineligibility for intensive treatment.

Allogeneic stem cell transplantation versus conventional therapy for advanced primary cutaneous T-cell lymphoma

BACKGROUND

Primary cutaneous T-cell lymphomas (CTCL) belong to the group of non-Hodgkin lymphomas and usually run an indolent course. However, some patients progress to advanced tumour or leukaemic stages. To date, there is no cure for those cases. In the last few years, several publications reported durable responses in some patients following allogeneic stem cell transplantation (alloSCT). This is an update of a Cochrane review first published in 2011 and updated in 2013.

OBJECTIVES

To compare the efficacy and safety of conventional therapies with allogeneic stem cell transplantation in patients with advanced primary cutaneous T-cell lymphomas.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 1), MEDLINE (1950 to January 2013), Internet-databases of ongoing trials, conference proceedings of the American Society of Clinical Oncology (ASCO, 2009 to July 2013) and the American Society of Hematology (ASH, 2009 to July 2013). We also contacted members of the European Organisation for Research and Treatment of Cancer (EORTC) Cutaneous Lymphoma Task Force to check for ongoing study activities. We handsearched citations from identified trials and relevant review articles. In addition, we handsearched randomised controlled trials from the European Group for Blood and Marrow Transplantation (EBMT) and International Conference on Cutaneous T-cell Lymphoma, ASCO and ASH up to July 2013.

SELECTION CRITERIA

Trials eligible for inclusion were genetically randomised controlled trials (RCTs) comparing alloSCT plus conditioning therapy (regardless of agents) with conventional therapy as treatment for advanced CTCL.

DATA COLLECTION AND ANALYSIS

Two review authors would have extracted data from eligible studies and assessed their quality. The primary outcome measure was overall survival; secondary outcomes were time to progression, response rate, treatment-related mortality, adverse events and quality of life.

MAIN RESULTS

We did not identify any randomised controlled trials from the updated search in January 2013. In 2011, we found 2077 citations but none were relevant genetically or non-genetically randomised controlled trials. All 41 studies that were thought to be potentially suitable were excluded after full text screening for being non-randomised, not including CTCL or being review articles.

AUTHORS' CONCLUSIONS

We planned to report evidence from genetically or non-genetically randomised controlled trials comparing conventional therapy and allogeneic stem cell transplantation. However, we did not identify any randomised controlled trials addressing this question. Nevertheless, prospective genetically randomised controlled trials need to be initiated to evaluate the precise role of alloSCT in advanced CTCL.

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

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

Comparative outcome of reduced intensity and myeloablative conditioning regimen in HLA identical sibling allogeneic hematopoietic stem cell transplantation for acute leukemia patients: a single center experience

Due to the high transplant related morbidity and mortality (TRM), relatively younger acute leukemia patients that have a good performance status and no comorbidity are eligible for myeloablative conditioning (MAC) followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT). The outcomes of 84 consecutive adult patients with ALL (n=38) or AML (n=46) who underwent allo-HSCT from their HLA-identical siblings were evaluated retrospectively. The median age at transplantation was 34 (17-58 years) for the whole patient population. Of these, 24 patients received a MAC and 60 patients received a fludarabine-based reduced intensity conditioning regimen (RIC). After a median follow-up of 32 months (range, 1-119), for the entire group, the 3-year estimated overall survival (OS) was 57.5% and the disease-free survival (DFS) was 51.5%. The OS for ALL and AML patients were 53.9% vs 62.1%: and DFS were 50.5% and 53.4%, respectively. The 3-year estimated OS for RIC and MAC patients were 63.2% and 41.7%; and DFS were 57.1% and 34.7%, respectively. In ALL patients, conditioning regimens (RIC vs MAC) led to similar OS and DFS; however, in AML patients both OS (70.1% vs 21.4%) and DFS (59.3% vs 42.9%) were found to be higher in RIC patients compared to MAC recipients. Overall, the TRM at day 100 was 1.7% and has increased up to 5.1% at 1st year. In multivariate analysis, the diagnosis (p=0.03) and RIC regimen (p=0.027) were the prognostic variables for prolonged OS in all patients; and RIC regimen (p=0.031) was the only prognostic factor for prolonged OS in AML patients. The first complete remission (CR1) was correlated with a prolonged DFS as an independent variable for all patients (p=0.09). Eleven of the RIC patients (18.3%) and 6 of the MAC patients (25%) developed acute graft-versus-host disease (GvHD). Seventeen of the RIC patients (33.3%) and 4 of the MAC patients (16.7%) developed chronic GvHD. In conclusion, RIC conditioning regimens may provide a longer OS and DFS, especially in patients with AML who are in first CR, not eligible for MAC conditioning.

A prospective randomized toxicity study to compare reduced-intensity and myeloablative conditioning in patients with myeloid leukaemia undergoing allogeneic haematopoietic stem cell transplantation

BACKGROUND

To our knowledge, no randomized toxicity studies have been conducted to compare myeloablative conditioning (MAC) and reduced-intensity conditioning (RIC) in allogeneic haematopoietic stem cell transplantation (HSCT).

METHODS

Adult patients ≤60 years of age with myeloid leukaemia were randomly assigned (1 : 1) to treatment with RIC (n = 18) or MAC (n = 19) in this Phase II single-centre toxicity study.

RESULTS

There was a maximum median mucositis grade of 1 in the RIC group compared with 4 in the MAC group (P < 0.001). Haemorrhagic cystitis occurred in eight of the patients in the MAC group and none in the RIC group (P < 0.01). Results of renal and hepatic tests did not differ significantly between the two groups. RIC-treated patients had faster platelet engraftment (P < 0.01) and required fewer erythrocyte and platelet transfusions (P < 0.001) and less total parenteral nutrition (TPN) than those treated with MAC (P < 0.01). Cytomegalovirus (CMV) infection was more common in the MAC group (14/19) than in the RIC group (6/18) (P = 0.02). Donor chimerism was similar in the two groups with regard to CD19 and CD33, but was delayed for CD3 in the RIC group. Five-year transplant-related mortality (TRM) was approximately 11% in both groups, and rates of relapse and survival were not significantly different. Patients in the MAC group with intermediate cytogenetic acute myeloid leukaemia had a 3-year survival of 73%, compared with 90% among those in the RIC group.

CONCLUSION

Reduced-intensity conditioning had several advantages compared with MAC, including less mucositis, less haemorrhagic cystitis, faster platelet engraftment, the need for fewer transfusions and less TPN, and fewer CMV infections. Both regimens were tolerated and TRM was low.

Expanded indications for allogeneic stem cell transplantation in patients with myeloid malignancies

PURPOSE OF REVIEW

Hematopoietic stem cell transplantation (SCT) can be curative for myeloid malignancies such as acute myeloid leukemia (AML). Advancements in human leukocyte antigen (HLA) typing and supportive care have improved the risk-benefit ratio for SCT, expanding its indications.

RECENT FINDINGS

Allogeneic SCT is an established treatment for AML with intermediate-risk and high-risk cytogenetics in first complete remission (CR1), from matched related donors (MRDs). Similar survival benefits are seen for AML in CR1 with unfavorable cytogenetics using matched unrelated donors (URDs). Molecular characterization has delineated patients with AML at higher risk with normal cytogenetics [e.g., FLT3-internal tandem duplication (ITD)+]. The outcomes of allogeneic SCT are comparable in patients with therapy-related or de-novo AML when adjusted for disease status and cytogenetics. In patients lacking a MRD, the majority will have a suitable alternative using an URD, umbilical cord blood, or haploidentical-related donors; outcomes are either comparable or relatively acceptable compared to a matched sibling donor. Comorbidity indices aid in identifying elderly and debilitated patients who may benefit from SCT; the application of SCT has been further increased by reduced-intensity conditioning regimens.

SUMMARY

Allogeneic SCT may be extended to almost all patients with AML, and integration of toxicity and relapse risks will determine the best approach for allogeneic SCT in the future.

Effect of graft source on mismatched unrelated donor hemopoietic stem cell transplantation after reduced intensity conditioning

This retrospective report compared the results of graft source on outcome after allogeneic stem cell transplantation (allo-SCT) in patients with hematologic malignancies receiving a reduced intensity conditioning (RIC) regimen. A total of 152 patients received either a RIC allo-SCT using a 9/10 mismatched unrelated donor (MisMUD, n=42) or a double unrelated umbilical cord blood (dUCB, n=110) graft. With a median follow-up of 30.3 months, the cumulative incidence of non-relapse mortality was 26% in the dUCB group versus 24% in the MisMUD group (P=0.95). Grade 3-4 acute graft-versus-host disease (GVHD) incidence was 19.7% in the dUCB group versus 21.4% in the MisMUD group (P=0.83). The cumulative incidence of extensive chronic GVHD at 2 years was 6.4% in the dUCB group versus 21.4% in the MisMUD group (P=0.02). The Kaplan-Meier estimate of overall survival at 2 years was comparable between both groups (52.3% (95% confidence interval (CI), 42.1-61.5%) in the dUCB group versus 47.9% (95% CI, 31.6-62.4%) in the MisMUD group, P=0.55). Progression-free survival at 2 years was 43.3% (95% CI, 33.7-52.5%) in the dUCB group versus 38.3% (95% CI, 23.2-53.3%) in the MisMUD group (P=0.55). These data suggest that dUCB is a valid alternative graft source with significantly less chronic GVHD compared with MisMUD in the setting of RIC allo-SCT.

A high antithymocyte globulin dose increases the risk of relapse after reduced intensity conditioning HSCT with unrelated donors

The study included 110 consecutive patients with hematological malignancies receiving fludarabine-based reduced intensity conditioning (RIC) and hematopoietic stem cell transplantation (HSCT) from matched unrelated donors. The median age was 55 yr (range 11-68) and all but 15 patients received peripheral blood stem cell grafts. Antithymocyte globulin (ATG) (Thymoglobulin, Genzyme) at a total dose of 6 mg/kg (n = 66) or 8 mg/kg (n = 44) was given to all patients according to protocol. The ATG dose did not affect time-to-neutrophil or platelet engraftment. The incidences of acute GVHD grades II-IV were 34% and 18% (p = 0.11) and of chronic GVHD were 40% and 26% (p = 0.46) in patients receiving 6 and 8 mg/kg of ATG, respectively. The five-yr relapse-free survival (RFS) was 61% and 36% (p = 0.14) in patients, given low and high ATG dose, respectively. In patients given low-dose ATG, the incidence of relapse was lower compared to those given high-dose ATG, 19% vs. 41% (p = 0.04). In multivariate analysis, age >50 yr (p < 0.001), absence of acute (p < 0.001) and chronic GVHD (p = 0.001) were correlated to relapse, and low-dose ATG was associated with improved RFS (p < 0.05). A high dose (8 mg/kg) of ATG in RIC HSCT with unrelated donors increased the risk for relapse and reduced the RFS.

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/m(2)/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.

A competing risks analysis should report results on all cause-specific hazards and cumulative incidence functions

Competing risks endpoints are frequently encountered in hematopoietic stem cell transplantation where patients are exposed to relapse and treatment-related mortality. Both cause-specific hazards and direct models for the cumulative incidence functions have been used for analyzing such competing risks endpoints. For both approaches, the popular models are of a proportional hazards type. Such models have been used for studying prognostic factors in acute and chronic leukemias. We argue that a complete understanding of the event dynamics requires that both hazards and cumulative incidence be analyzed side by side, and that this is generally the most rigorous scientific approach to analyzing competing risks data. That is, understanding the effects of covariates on cause-specific hazards and cumulative incidence functions go hand in hand. A case study illustrates our proposal.