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Second allogeneic hematopoietic stem cell transplantation (HSCT) is a treatment option for patients with acute leukemia who relapse after a first HSCT. Although myeloablative conditioning (MAC) regimens before the first HSCT are considered superior to reduced- intensity conditioning (RIC) in terms of disease control in acute leukemia patients, the optimal conditioning regimen for the second allogeneic HSCT remains controversial. The most important prognostic factors are the remission disease phase at the time of the second HSCT and an interval >12 months from the first HSCT to the second HSCT. Total marrow irradiation (TMI) is an advanced high-precision radiation treatment that delivers therapeutic doses over extensively selected targets while substantially reducing radiation to vital organs compared to conventional total body irradiation (TBI). Here we report the results of a retrospective analysis of second allogeneic HSCT treated with TMI as an MAC regimen with the intent of limiting toxicity. We investigated the efficacy of high dose per fraction TMI in combination with thiotepa, fludarabine, and melphalan in 13 consecutive patients with acute leukemia who had relapsed after a first allogeneic HSCT treated between March 2018 and November 2021. Donor type was haploidentical in 10 patients, unrelated in 2 patients, and HLA-identical sibling in 1 patient. The conditioning regimen consisted of 8 Gy TMI in 5 patients on days -8 and -7 and 12 Gy TMI in 8 patients on days -9 to -7, plus thiotepa 5 mg/kg on day -6, fludarabine 50 mg/day on days -5 to -3, and melphalan 140 mg/day on day -2. The TMI was delivered at the dosage og 4 GY for 2 consecutive days (total = 8 GY) or for 3 consecutive days (total = 12 GY). The median patient age was 45 years (range, 19 to 70 years); 7 patients were in remission, and 6 had active disease at the time of their second allogeneic HSCT. The median time to a neutrophil count of >.5 × 10 9 /L was 16 days (range, 13 to 22 days), and the median time to a platelet count of >20 × 10 9 /L was 20 days (range, 14 to 34 days). All patients showed complete donor chimerism on day +30 post-transplantation. The cumulative incidence of grade I-II acute graft-versus-host disease (GVHD) was 43%, and that of chronic GVHD was 30%. The median duration of follow-up was 1121 days (range, 200 to 1540 days). Day +30 and +100 transplantation-related mortality (TRM) was 0. The overall cumulative incidence of TRM, relapse rate, and disease free-survival were 27%, 7%, and 67%, respectively. This retrospective study demonstrates the safety and efficacy of a hypofractionated TMI conditioning regimen in patients with acute leukemia undergoing second HSCT with encouraging outcomes in terms of engraftment, early toxicity, GVHD, and relapse., (Copyright © 2023 The American Society for Transplantation and Cellular Therapy. All rights reserved.)

Myelodysplastic syndromes (MDS) are the second common indication for an Allo-HCT. We compared the outcomes of 1414 matched sibling (MSD) with 415 haplo-identical donors (HD) transplanted with post-transplant cyclophosphamide (PTCy) as GVHD prophylaxis between 2014 and 2017. The median age at transplant with MSD was 58 and 61 years for HD. The median time to neutrophil engraftment was longer for HD being 20 vs 16 days for MSD (p < 0.001). Two-year overall survival (OS) and PFS (progression free survival) with MSD were significantly better at 58% compared with 50%, p ≤ 0.001, and 51% vs 47%, p = 0.029, with a HD. Relapse at 2 years was lower with a HD 23% than with MSD 29% (p = 0.016). Non relapse mortality (NRM) was higher with HD in the first 6 months post-transplant [HR 2.59 (1.5-4.48) p < 0.001] and was also higher at 2 years being 30% for HD and 20% for MSD, p ≤ 0.001. The incidence of acute GVHD grade II-IV and III-IV at 100 days was comparable for MSD and HD, however, chronic GVHD at 2 years was significantly higher with MSD being 44% vs 32% for HD (p < 0.001). After multivariable analysis, OS and primary graft failure were significantly worse for HD particularly before 6 months [HR 1.93(1.24-3.0)], and HR [3.5(1.5-8.1)]. The median age of HD 37 (IQR 30-47) years was significantly lower than sibling donors 56 (IQR 49-62 years) p < 0.001. However, there was no effect on NRM, relapse or PFS. This data set suggests that a MSD donor remains the preferred choice in MDS over a haplo donor. Transplants with haploidentical donors result in satisfactory long-term outcome, justifying it's use when no better donor is available., (© 2022. The Author(s).)

The outcome of refractory/relapsed (R/R) acute leukemias is still dismal and their treatment represents an unmet clinical need. However, allogeneic transplantation (allo-HSCT) remains the only potentially curative approach in this setting. A prospective study (GANDALF-01, NCT01814488; EUDRACT:2012-004008-37) on transplantation with alternative donors had been run by GITMO using a homogeneous myeloablative conditioning regimen with busulfan, thiotepa and fludarabine while GVHD prophylaxis was stratified by donor type. The study enrolled 101 patients; 90 found an alternative donor and 87 ultimately underwent allo-HSCT. Two-year overall survival of the entire and of the transplant population (primary endpoint) were 19% and 22%, without significant differences according to disease, donor type and disease history (relapsed vs refractory patients). Two-year progression-free survival was 19% and 17% respectively. The cumulative incidences of relapse and non-relapse mortality were 49% and 33% at two years. Acute grade II-IV and chronic GVHD occurred in 23 and 10 patients. Dose intensification with a myeloablative two-alkylating regimen as sole strategy for transplanting R/R acute leukemia does seem neither to improve the outcome nor to control disease relapse. A pre-planned relapse prevention should be included in the transplant strategy in this patient population., (© 2022. The Author(s).)

The aim of this study was to develop a predictive score for moderate-severe chronic graft-versus-host disease (cGVHD) on day +100 after allogeneic stem cell transplantation (HSCT). We studied 1292 patients allografted between 1990 and 2016, alive on day +100 after transplant, without cGVHD, and with full biochemistry laboratory values available. Patients were randomly assigned to a training and a validation cohort (ratio 1:1). In the training cohort, a multivariate analysis identified 4 independent predictors of moderate-severe cGVHD: gamma-glutamyl transferase ≥75 UI/l, creatinine ≥1 mg/dl, cholinesterase ≤4576 UI/l, and albumin ≤4 g/dl. A score of 1 was assigned to each variable, producing a low (0 to 1), intermediate (2 to 3), and high (4) score. The cumulative incidence of moderate-severe cGVHD was 12%, 20%, and 52% (P < .0001) in the training cohort, and 13%, 24%, and 33% (P = .002) in the validation cohort, respectively. The 5-year cumulative incidence of transplant-related mortality (TRM) was 5%, 14%, 27% (P < .0001) and 5%, 16%, 31% (P < .0001), respectively. The 5-year survival was 64%, 57%, 54% (P = .009) and 70%, 59%, 42% (P = .0008) in the 2 cohorts, respectively. In conclusion, Day100 score predicts cGVHD, TRM, and survival and, if validated in a separate group of patients, could be considered for trials of preemptive therapy., (© 2022 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

We report the outcome of 19 patients who experienced primary graft failure (PrGF) after a haploidentical (HAPLO), unmanipulated bone marrow transplant. The median age of patients was 52 years; the conditioning regimen of the first HAPLO transplant was either full dose total body irradiation (TBI) or fludarabine, busulfan, and thiotepa (TBF); PTCY was given to all patients together with cyclosporine and mycophenolate. All 19 patients with PrGF received a second HAPLO graft, at a median interval of 42 days (34-82) after HSCT, using the Baltimore protocol and G-CSF mobilized PB from the same (n = 13) or another HAPLO family donor (n = 6). GvHD prophylaxis was again PTCY-based; 14/19 patients had trilineage recovery (74%) and 1-year survival was 66%. Engraftment at second HAPLO was seen in 7/8 patient with, and in 5/7 patients without donor-specific antibodies (DSA). In a multivariate logistic regression analysis on the original group of 503 patients, there was a trend for a reduced dose of busulfan, to increase the risk of PrGF (p = 0.1). In conclusion, patients with PrGF following a HAPLO transplant, can be rescued with a second early HAPLO transplant, using the same or a different donor.

We have treated 69 patients with steroid refractory acute graft versus host disease (SR-aGvHD), with an anti-CD26 monoclonal antibody (Begelomab): 28 patients in two prospective studies (EudraCT No. 2007-005809-21; EudraCT No. 2012-001353-19), and 41 patients on a compassionate use study. The median age of patients was 42 and 44 years; the severity of GvHD was as follows: grade II in 8 patients, grade III in 33, and grade IV in 28 patients. There were no adverse events directly attributable to the antibody. Day 28 response was 75% in the prospective studies and 61% in the compassionate use patients, with complete response rates of 11 and 12%. Response for grade III GvHD was 83 and 73% in the two groups; response in grade IV GvHD was 66 and 56% in the two groups. Non relapse mortality (NRM) at 6 months was 28 and 38%. Overall there were 64, 56, 68% responses for skin, liver, and gut stage 3-4 GvHD. The overall survival at 1 year was 50% for the prospective studies and 33% for the compassionate use patients. In conclusion, Begelomab induces over 60% responses in SR-aGvHD, including patients with severe gut and liver GvHD, having failed one or more lines of treatment.

This is an update on acute and chronic graft-versus-host disease (GvHD) in 425 patients with hematologic malignancies, undergoing an unmanipulated haploidentical (HAPLO) graft from related donors, with a modified post-transplant cyclophosphamide (PT-CY) regimen. All patients received a myeloablative conditioning regimen, either based on thiotepa busulfan fludarabine (TBF), or on full-dose total body irradiation (TBI). The cumulative incidence of acute GvHD-grade II-IV was 29%, and the CI of GvHD-grade III-IV was 4%. We found older donors and older patients to have higher rates of grade II-IV acute GvHD; female donors, diagnosis, disease phase, year of transplant, and the conditioning regimen had no predictive effect on acute GvHD. There was no impact of grade II GvHD, but a significant impact of grade III-IV acute GvHD, on overall survival. The CI of moderate-severe chronic GvHD was 18%: the major predictor was a previous acute GvHD, followed by combined donor and recipients age. In conclusion, PT-CY given on days+3 + 5 results in a relatively low, but not insignificant risk of acute and chronic GvHD, in patients grafted from the related HAPLO donors. The use of young donors appears to reduce this risk.

This is a report of 148 patients with hematologic malignancies who received an unmanipulated haploidentical bone marrow transplant (BMT), followed by post-transplant high-dose cyclophosphamide (PT-CY). All patients received a myeloablative conditioning consisting of thiotepa, busulfan, fludarabine (n=92) or TBI, fludarabine (n=56). The median age was 47 years (17-74); 47 patients were in first remission (CR1), 37 in second remission (CR2) and 64 had an active disease; all patients were first grafts. The diagnosis was acute leukemia (n=75), myelodisplastic syndrome (n=24), myelofibrosis (n=16), high-grade lymphoma (n=15) and others (n=18). GVHD prophylaxis consisted in PT-CY on days +3 and +5, cyclosporine (from day 0), and mycophenolate (from day +1). The median day for neutrophil engraftment was day +18 (13-32). The cumulative incidence of grades II-IV acute GVHD was 24%, and of grades III-IV GVHD 10%. The incidence of moderate-severe chronic GVHD was 12%. With a median follow-up for the surviving patients of 313 days (100-1162), the cumulative incidence of transplant-related mortality (TRM) is 13%, and the relapse-related death is 23%. The actuarial 22 months overall survival is 77% for CR1 patients, 49% for CR2 patients and 38% for patients grafted in relapse (P<0.001). Major causes of death were relapse (22%), GVHD (2%) and infections (6%). We confirm our initial results, suggesting that a myeloablative conditioning regimen followed by unmanipulated haploidentical BMT with PT-CY, results in a low risk of acute and chronic GVHD and encouraging rates of TRM and overall survival, also for patients with active disease at the time of transplant.

Forty-two patients relapsing after an unmanipulated haploidentical BM transplant and post-transplant CY (PT-CY), were given 108 DLI, with median interval from transplant of 266 days (range, 67-1372). DLI were given at escalating doses, expressed as CD3+ cells/kg, without GVHD prophylaxis, and ranged from 1 × 10(3) to 1 × 10(7) cells/kg (median 5 × 10(5) cells/kg). The average number of DLI per patient was 2.6 (range, 1-6). The diagnosis was leukemias (n=32) grafted with a myeloablative regimen and Hodgkin's disease (n=10), grafted with a nonmyeloablative regimen. Leukemic patients with molecular relapse (n=20), received DLI alone (n=17) or in association with azacytidine (n=3); leukemic patients with hematologic relapse (n=12) received chemotherapy followed by DLI (n=11) or DLI alone (n=1); Hodgkin patients received DLI following 1-3 courses of chemotherapy. In these three groups the incidence of acute GVHD II-III was 15%, 17% and 10%; response rate was 45%, 33% and 70%; 2-year actuarial survival was 43%, 19% and 80% respectively. This study confirms that escalating doses of DLI can be given in the haploidentical setting with PT-CY, with a relatively low risk of acute GVHD. Response rates and survival are dependent on the underlying disease.

We studied 459 consecutive patients with hematologic malignancies, median age 44 years (range, 15 to 71 years), who underwent transplantation with grafts from identical sibling donors (SIB; n = 176), matched unrelated donors (MUD; n = 43), mismatched unrelated donors (mmUD; n = 43), unrelated cord blood (UCB; n = 105) or HLA-haploidentical family donors (HAPLO; n = 92). Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and methotrexate in the SIB recipients; antithymocyte globulin for the MUD, mmUD, and UCB recipients; and post-transplantation cyclophosphamide, cyclosporine, and mycophenolate in the HAPLO recipients. Conditioning regimens were mostly myeloablative (69%). Advanced disease phase was more frequent, but not significantly so, in the HAPLO and mmUD groups (P = .08). Acute GVHD grade II-IV was significantly less frequent in the HAPLO, UCB, and MUD groups (14% to 21%) compared with the SIB (31%) and mmUD (42%) groups (P < .001), and there was a trend toward less moderate-severe chronic GVHD in the HAPLO and UCB groups (P = .053). The proportion of patients off cyclosporine at 1 year ranged from 55% for the SIB group to 81% for the HAPLO group (P < .001). Transplantation-related mortality at 2 years was lower in the HAPLO and SIB groups (18% to 24%) compared with the MUD, mmUD, and UCB groups (33% to 35%; P = .10). Relapse rate was comparable in the 5 groups (P = .80). The 4-year actuarial survival was 45% in the SIB group, 43% in the MUD group, 40% in the mmUD group, 34% in the UCB group, and 52% in the HAPLO group (P = .10). In multivariate analysis, advanced disease was a negative predictor of survival (hazard ratio [HR], 2.4; P < .0001), together with a diagnosis of acute leukemia (HR, 1.8; P = .0001); HAPLO grafts were comparable to SIB (P = .80), whereas UCB had inferior survival (P = .03). In conclusion, unmanipulated haploidentical family donor transplants are an additional option for patients lacking a matched sibling donor., (Copyright © 2014 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Poor graft function (PGF) is characterized by pancytopenia and a hypoplastic marrow, with complete donor chimerism, usually without severe graft-versus-host disease (GVHD). We report 41 patients with PGF, treated with granulocyte colony-stimulating factor-mobilized CD34 selected cells, at a median interval from transplant of 140 days, without conditioning and without GVHD prophylaxis. Donors were HLA matched siblings (n = 12), unrelated donors (n = 18), or mismatched family members (n = 11). The median number of infused CD34(+) cells was 3.4 × 10(6)/kg. The rate of trilineage recovery was 75%: 83% for HLA matched siblings and 72% for unrelated and mismatched family members (P = .3). The cumulative incidence of acute grade II GVHD was 15%, and no patient developed de novo chronic GVHD. The actuarial 3-year survival is 63%: 76% and 25% for patients with or without trilineage recovery. These data confirm the role of CD34(+) selected cells from the same donor in the treatment of PGF and warrant the request for a second donation also when the donor is unrelated., (Copyright © 2014 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Extracorporeal photopheresis (ECP) was given to 23 patients with steroid-refractory acute GVHD (aGVHD, grade II (n=10), III (n=7) or IV (n=6)). The median duration of ECP was 7 months (1-33) and the median number of ECP cycles in each patient was 10. Twelve patients (52%) had complete responses. Eleven patients (48%) survived and 12 died, 10 of GVHD with or without infections and two of leukaemia relapse. The average grade of GVHD was reduced from 2.8 (on the first day of ECP) to 1.4 (on day +90 from ECP) (P=0.08), and the average dose of i.v. methylprednisolone from 2.17 to 0.2 mg/kg/d (P=0.004). Complete responses were obtained in 70, 42 and 0% of patients, respectively, with grades II, III and IV aGVHD; complete responses in the skin, liver and gut were 66, 27 and 40%. Patients treated within 35 days from onset of aGVHD had higher responses (83 vs 47%; P=0.1). A trend for improved survival was seen in grade III-IV aGVHD treated with ECP as compared to matched controls (38 vs 16%; P 0.08). ECP is a treatment option for patients with steroid refractory aGVHD and should be considered early in the course of the disease.

In the present study, we analyze factors predicting graft-versus-host disease (GvHD) and response after donor lymphocyte infusions (DLI). A total of 100 patients received 593 DLI between June 1990 and December 2000 in a bulk dose (n=14) or in escalating dose infusions (n=86). Patients were analyzed after stratification for type of relapse: (1). molecular relapse (n=6), (2). cytogenetic relapse (n=20), (3). chronic phase of chronic myeloid leukemia (CML) or complete remission of other disease post chemotherapy (n=24), (4). CML in accelerated/blastic phase (n=14), (5). resistant disease not responding to chemotherapy (n=36). The proportion of responders to DLI in these five groups was 100, 90, 75, 36 and 0% (P<0.0001). Factors predicting response by multivariate analysis were type of relapse (P<0.0001), post-DLI GvHD (P=0.005), pancytopenia (P=0.008), and a diagnosis of CML (P=0.04). Acute GvHD (grades II-IV) occurred in 21 patients (21%), and correlated in multivariate analysis with pancytopenia and less than four DLI. Other predictors of GvHD were the number of CD3+cells/infusion and serum levels of gamma-glutamyl transferase (gammaGT). The actuarial probability of treatment-related mortality was 9% for HLA identical siblings and 44% for alternative donor transplants (P=0.006). Response to DLI is predicted by tumor burden and is associated with GvHD and pancytopenia.

Background and Objectives: The efficacy of antithymocyte globulin (ATG) in the treatment of graft-versus-host disease (GvHD) is controversial. In the present study we report on the use of low dose ATG (thymoglobuline, Sangstat) and steroids in 28 patients with moderate to severe acute GvHD., Design and Methods: Fifteen patients received ATG as first-line treatment within 14 days of the diagnosis of GvHD (median 8 days, range 4-13). Twelve patients received ATG as second-line therapy, more than 14 days after diagnosis (median 32 days, range 14 to 98). The proportion of patients with severe (grade III-IV) GvHD at the time of ATG therapy was 4/15 in the former group and 7/13 in the latter (p=0.1)., Results: On day 30 after ATG the overall proportion of responders was 80% in the group administered ATG early and 38% in those given it later (p=0.03). The overall actuarial 3-year transplant-related mortality was 40% vs 74% for the early vs late ATG groups (p=0.03); the actuarial 3-year survival was, respectively, 49% vs 23% (p=0.04). For patients with GvHD grade III-IV the actuarial 1-year TRM was 47% for those given ATG early, 87% for the late ATG group and 82% for a concurrent control group of 26 patients not treated with ATG., Interpretation and Conclusions: In conclusion, ATG may be considered for early treatment of acute GvHD, within a few days from the onset of the disease. A prospective trial has been started to test whether, in this setting, low dose ATG with steroids is superior to steroids alone.

We studied the impact of preparative regimens with or without antithymocyte globulin (ATG) on chronic GVHD in 160 patients undergoing marrow transplants from unrelated donors (n = 127) or partially mismatched related donors (n = 33). A conditioning regimen that included rabbit ATG, 7.5 to 15 mg/kg (Thymoglobuline; Sangstat, Lyon, France), was given to 102 patients, whereas a conditioning regimen without ATG was given to 58 patients. The median patient age was 34 years for the ATG group and 29 years for the non-ATG group (P = .002); otherwise the 2 groups were matched for disease phase, diagnosis, donor age, interval from diagnosis to transplantation, and number of cells infused at the time of transplant. Median follow-up for surviving patients was 4.5 years (range, l.5-9 years). The conditioning regimen was cyclophosphamide (CY) and total body irradiation (TBI) in 95 patients and CY-thiotepa in 65 patients; the source of stem cells was bone marrow for all patients. Acute GVHD grades II-IV and grades III-IV were reduced in patients receiving ATG compared to patients not receiving ATG (51% versus 74%, P = .004 and 14% versus 28%, P = .03, respectively). There were significantly fewer patients with chronic GVHD in the ATG group than in the non-ATG group at 6 months (14% versus 30%, P = .03), 1 year (7% versus 41%, P = .0001), 2 years (16% versus 36%, P = .02), and 4 years (5% versus 34%, P = .002) and beyond 4 years (0% in 19 patients at risk versus 29% in 24 patients at risk, P = .01). More patients in the ATG group than in the non-ATG group had a performance status (Karnowski score) greater than 90 at last follow-up (93% versus 56%, P = .01) and had discontinued cyclosporin treatment 2 years posttransplant (28% versus 3%, P = .003). Survival rates were comparable in the ATG and non-ATG groups for patients who received TBI (56% versus 59%, P = .7) and those who received thiotepa (33% versus 18%, P = .3). Transplant mortality and relapse rates were also comparable in the 2 groups for these patients. We conclude that pretransplant ATG administration reduces the risk of acute and chronic GVHD, improves quality of life, and increases the likelihood that discontinuation of immunosuppressive therapy will be possible.

Serum cholinesterase (CHE) has been reported to be a significant indicator of liver function and prognosis in patients with cirrhosis. On the other hand, liver complications are frequent following allogeneic stem cell transplantation (HSCT). We therefore tested whether CHE was predictive of graft-versus-host disease and outcome in HSCT recipients. We studied 689 patients receiving a HSCT from an HLA-identical sibling (SIB) (n = 511), an alternative donor (n = 173) or a syngeneic twin (n = 5). Acute graft-versus-host disease (GVHD) was scored as 0-I, II, III-IV in 325 (47%), 279 (41%), and 85 patients (12%) respectively; 190 (28%) patients died of transplant-related complications (TRM). On day -7 the median CHE serum level was comparable in patients who either survived or died of TRM (5900 IU/l). On day 0, serum CHE levels were respectively 2310 and 2120 IU/l (P = NS) indicating the impact of the conditioning regimen. On day +7 after HSCT, the median level for surviving patients was 2598 IU/l vs 2309 IU/l for patients who subsequently died (P = 0.0002), on day +21 CHE levels were respectively 3348 vs 2528 IU/l (P < 0.00001), on day +50, 3575 vs 2358 IU/l (P < 0.00001) and on day +100 4193 vs 2729 IU/l (P < 0.00001). CHE levels on day +50 strongly correlated with aGVHD (3803 vs 3070 vs 1933 IU/l for patients with GVHD grade 0-I, II, and III-IV, respectively (P < 0.00001) and relapse (3569 for patients relapsing vs 3115 IU/l for patients not relapsing, P = 0.0006). In conclusion, (1) serum cholinesterase is a simple and reliable marker of acute GVHD and transplant-related complications; and (2) high CHE levels on day +50 predict relapse. If confirmed, the latter patients may be eligible for early reduction of immunosuppressive therapy.

We have previously shown that patients at high risk of graft-versus-host disease (GVHD) and transplant-related mortality (TRM) can be identified on day +7 following an allogeneic bone marrow transplant (BMT), based on serum bilirubin and blood urea nitrogen levels. One possible approach to reduce the risk of GVHD and TRM, is pre-emptive treatment with T cell antibodies. We report a pilot study testing the feasibility of this approach in 18 high risk patients, with a median age of 41, 83% of whom had advanced disease, undergoing an alternative donor BMT (family mismatched in five and unrelated in 13). The patients received three doses of rabbit antithymocyte globulin (ATG) (Thymoglobuline; Sangstat) 1.25 mg/kg on alternate days, starting at a median interval of 11 days (range 7-13) after BMT. Controls were 20 historical unrelated donor transplants (median age 35, 63% with advanced disease), with a high score from our original publication in 1999. The actuarial 1 year TRM of the ATG-treated patients was 40% compared to 60% for untreated controls (P = 0.06). Severe grade III-IV aGVHD developed in 27% of the ATG-treated patients, and in 55% of the controls (P = 0.08). This study indicates that early pre-emptive treatment of aGVHD in day +7 high risk patients is feasible and may lead to a reduction of aGVHD and TRM. This approach is being tested in a prospective randomized trial.