Outcomes in Patients Age 70 or Older Undergoing Allogeneic Hematopoietic Stem Cell Transplantation for Hematologic Malignancies

Allogeneic hematopoietic stem cell transplantation (HSCT) can achieve durable remissions in a number of patients with advanced hematologic malignancies. Little is known about the safety of HSCT in patients age 70 or older. Consecutive patients (n = 54) age 70 or older underwent HSCT between 2007 and 2012. Diseases included acute myelogenous leukemia (n = 25), myelodysplastic syndrome (n = 12), chronic lymphocytic leukemia (n = 5), non-Hodgkin lymphoma (n = 4), acute lymphoblastic leukemia (n = 3), myeloproliferative neoplasm (n = 4), and chronic myelogenous leukemia (n = 1). Median follow-up for survivors was 21 months. All patients received reduced-intensity conditioning regimens, primarily busulfan/fludarabine. All patients received unmanipulated peripheral blood stem cell grafts: 44 from 8/8 matched unrelated donors, 8 from matched related donors, and 2 from 7/8 matched unrelated donors. Graft-versus-host disease (GVHD) prophylaxis was calcineurin inhibitor–based in all patients. The median age at transplantation was 71 years (range, 70 to 76); the median HCT comorbidity index score was 1 (range, 0 to 5). Two patients died before hematopoietic recovery (1 with graft failure and 1 with disease progression), and 1 patient relapsed before hematopoietic recovery; otherwise, all engrafted with median donor chimerism of 94% at 1 month. Cumulative incidence of grades II to IV acute GVHD was 13% and of grades III to IV acute GVHD, 9.3%. At 2 years, the cumulative incidence of chronic GVHD was 36%, progression-free survival was 39%, overall survival was 39%, and relapse was 56%. Nonrelapse mortality was 3.7% at day +100 and 5.6% at 2 years. We conclude that allogeneic HSCT is a safe and effective option for carefully selected patients age 70 or older.     

Reduced-Intensity Conditioning Followed by Related and Unrelated Allografts for Hematologic Malignancies: Expanded Analysis and Long-Term Follow-Up

Reduced-intensity conditioning (RIC) extends the curative potential of allogeneic hematopoietic cell transplantation (HCT) to patients with hematologic malignancies unable to withstand myeloablative conditioning. We prospectively analyzed the outcomes of 292 consecutive patients, median age 58 years (range, 19 to 75) with hematologic malignancies treated with a uniform RIC regimen of cyclophosphamide, fludarabine, and total body irradiation (200 cGy) with or without antithymocyte globulin and cyclosporine and mycophenolate mofetil graft-versus-host disease (GVHD) prophylaxis followed by allogeneic HCT at the University of Minnesota from 2002 to 6. Probability of 5-year overall survival was 78% for patients with indolent non-Hodgkin lymphoma, 53% for chronic myelogenous leukemia, 55% for Hodgkin lymphoma, 40% for acute myelogenous leukemia, 37% for myelodysplastic syndrome, 29% for myeloma, and 14% for myeloproliferative neoplasms. Corresponding outcomes for relapse were 0%, 13%, 53%, 37%, 39%, 75%, and 29%, respectively. Disease risk index (DRI) predicted both survival and relapse with superior survival (64%) and lowest relapse (16%) in those with low risk score compared with 24% survival and 57% relapse in those with high/very-high risk scores. Recipient cytomegalovirus (CMV)-positive serostatus was protective from relapse with the lowest rates in those also receiving a CMV-positive donor graft (29%). The cumulative incidence of 2-year nonrelapse mortality was 26% and was lowest in those receiving a matched sibling graft at 21%, with low (21%) or intermediate (18%) HCT-specific comorbidity index, and was similar across age groups. The incidence of grades II to IV acute GVHD was 43% and grades III to IV 27%; the highest rates were found in those receiving an unrelated donor (URD) peripheral blood stem cell (PBSC) graft, at 50%. Chronic GVHD at 1 year was 36%.Future approaches incorporating alternative GVHD prophylaxis, particularly for URD PBSC grafts, and targeted post-transplant antineoplastic therapies for those with high DRI are indicated to improve these outcomes.     

Prospective Multicenter Study of Single-Unit Cord Blood Transplantation with Myeloablative Conditioning for Adult Patients with High-Risk Hematologic Malignancies

Although the use of cord blood transplantation (CBT) is increasing, the optimal methods for conditioning and graft-versus-host disease (GVHD) prophylaxis remain to be established. Among previous reports, the Institute of Medical Science, University of Tokyo (IMSUT) has reported remarkably favorable results of CBT for hematologic malignancies as a single-institute experience. The aim of the present multicenter prospective study was to assess the safety and efficacy of CBT performed precisely according to IMSUT transplantation procedures. Thirty-three adult patients with hematologic malignancies, such as acute leukemia, chronic myelogenous leukemia, or myelodysplastic syndrome, either lacking an HLA-identical sibling/HLA-matched unrelated donor or requiring urgent transplantation were enrolled. Conditioning consisted of total body irradiation (12 Gy), cytarabine, and cyclophosphamide. Cyclosporine A and methotrexate were used for GVHD prophylaxis. Diagnoses were acute leukemia in 26 patients, chronic myelogenous leukemia in 4, and myelodysplastic syndrome in 3; 12 patients were in first complete remission, and the others were in advanced stages at the time of CBT. Thirty-one patients achieved engraftment, and the cumulative incidence of grade II-IV acute GVHD was 45% (95% confidence interval, 28%-62%). With a median follow-up of 46.2 months in 16 surviving patients, the 1-year cumulative incidence of nonrelapse mortality was 15% (95% confidence interval, 5%-30%). Causes of nonrelapse mortality were infection (n = 4) and graft failure (n = 1). The overall and disease-free survival rates were 51% (95% CI, 34%-68%) and 42% (95% CI, 26%-59%), respectively. These results suggest that the IMSUT CBT procedures can safely provide a high disease-free survival rate in patients with high-risk hematologic malignancies.     

Unmanipulated Haploidentical Bone Marrow Transplantation and Posttransplantation Cyclophosphamide for Hematologic Malignancies after Myeloablative Conditioning

Fifty patients with high-risk hematologic malignancies, underwent an unmanipulated haploidentical bone marrow transplantation (BMT), followed by posttransplantation high-dose cyclophosphamide (PT-CY): the myeloablative (MA) conditioning consisted of thiotepa, busulfan, fludarabine (n = 35), or total body irradiation (TBI), fludarabine (n = 15). The median age was 42 years (range, 18-66 years); 23 patients were in remission, 27 had active disease, and 10 patients were receiving a second allograft. Graft-versus-host disease (GVHD) prophylaxis consisted in PT-CY on day +3 and +5, cyclosporine (from day 0), and mycophenolate (from day +1). Three patients died before engraftment, and 2 patients had autologous recovery: 45 patients (90%) had full-donor chimerism on day +30. The median day for neutrophil engraftment was day +18 (range, 13-30 days). The cumulative incidence of grade II-III acute GVHD (aGVHD) was 12%, and of moderate chronic GVHD (cGVHD) 10%. With a median follow-up for surviving patients of 333 days (range, 149-623 days), the cumulative incidence of transplantation-related mortality (TRM) was 18%, and the rate of relapse was 26%. The actuarial 22-month disease-free survival (DFS) rate was 68% for patients in remission and 37% for patients with active disease (P < .001). Causes of death were pneumonia (n = 3), hemorrhage (n = 3), sepsis (n = 3), and relapse (n = 7). In conclusion, an MA conditioning regimen followed by haploidentical BMT with PT-CY results in a low risk of aGVHD and cGVHD and encouraging rates of TRM and DFS.     

Allogeneic Stem Cell Transplantation for Patients with Lower-Risk Myelodysplastic Syndrome

The indication for allogeneic stem cell transplantation (SCT) in patients with lower-risk myelodysplastic syndrome (MDS) is controversial. Here we report 60 patients with a low risk (n = 32) or intermediate risk (n = 28) classification according to the revised International Prognostic Scoring System (IPSS-R) who underwent allogeneic SCT with a reduced-intensity conditioning (n = 45) or myeloablative conditioning (n = 15) regimen from an HLA-identical sibling (n = 9), a matched unrelated donor (n = 36), or a mismatched unrelated donor (n = 15). The rates of grade II-IV and grade III-IV acute graft-versus-host disease were 32% and 7%, respectively, resulting in a transplantation-related mortality (TRM) of 17% at 3 years. The cumulative incidence of relapse at 5 years was only 7%, resulting in a 5-year disease-free survival of 72% and overall survival (OS) of 79%. Transplantation from a fully matched donor resulted in significantly improved OS at 5 years (91% versus 70%). Allogeneic SCT in lower-risk MDS (IPSS-R low or intermediate risk) from an HLA-matched donor resulted in excellent OS with a low risk of relapse.     

Clofarabine and Treosulfan as Conditioning for Matched Related and Unrelated Hematopoietic Stem Cell Transplantation: Results from the Clo3o Phase II Trial

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) can be curative for patients with hematologic malignancies. The ideal conditioning regimen before allo-HSCT has not been established. We conducted a Phase II study to evaluate the tolerability and efficacy of clofarabine and treosulfan as conditioning regimen before allo-HSCT. The primary objective was to evaluate the cumulative incidence of nonrelapse mortality (NRM) on day +100. Forty-four patients (36 with acute myelogenous leukemia, 5 with acute lymphoblastic leukemia, 3 with myelodysplastic syndromes) were enrolled. The median patient age was 47 years, and the median duration of follow-up was 27 months. The conditioning regimen was based on clofarabine 40 mg/m² (days -6 to -2) and treosulfan 14 g/m² (days -6 to -4). Allogeneic hematopoietic stem cells were derived from a sibling (n = 22) or a well-matched unrelated donor (n = 22). Graft-versus-host disease (GVHD) prophylaxis consisted of antithymocyte globulin, rituximab, cyclosporine, and a short-course of methotrexate. The regimen allowed for rapid engraftment and a 100-day NRM of 18%, due mainly to bacterial infections. The incidences of grade II-IV acute GVHD and chronic GVHD were 16% and 19%, respectively. The rates of overall survival (OS), progression-free survival, and relapse at 2 years were 51%, 31%, and 50%, respectively. Significantly different outcomes were observed between patients with low-intermediate and patients with high-very high Disease Risk Index (DRI) scores (1-year OS, 78% and 24%, respectively). Our findings show that the use of treosulfan and clofarabine as a conditioning regimen for allo-HSCT is feasible, with a 78% 1-year OS in patients with a low-intermediate DRI score. However, 1-year NRM was 18%, and despite the intensified conditioning regimen, relapse incidence remains a major issue in patients with poor prognostic risk factors.     

Single Infusion of Donor Mononuclear Early Apoptotic Cells as Prophylaxis for Graft-versus-Host Disease in Myeloablative HLA-Matched Allogeneic Bone Marrow Transplantation: A Phase I/IIa Clinical Trial

Because of its potent immunomodulatory effect, an infusion of donor mononuclear early apoptotic cells (ApoCell) was tested in addition to cyclosporine and methotrexate as prophylaxis for acute graft-versus-host disease (GVHD) after HLA-matched myeloablative allogeneic hematopoietic stem cell transplantation (HSCT) from a related donor. In a phase I/IIa clinical trial, we treated 13 patients (median age, 37 years; range, 20 to 59 years) with hematologic malignancies: 7 patients with acute lymphoblastic leukemia, 5 patients with acute myeloid leukemia, and 1 patient with chronic myeloid leukemia, who received conventional myeloablative conditioning, with 35, 70, 140, or 210 × 10⁶ cell/kg of donor ApoCell, on day -1 of transplantation. Engraftment was successful in all patients with median time to neutrophil recovery of 13 days (range, 11 to 19), and platelet recovery of 15 days (range, 11 to 59). Serious adverse effects were reported on 10 occasions in the trial, all of which were considered unrelated (n = 7) or unlikely to be related (n = 3) to ApoCell infusion. The nonrelapse mortality at day 100 and 180 after transplantation was 7.7% and the overall survival at 100 and 180 days after transplantation was 92% and 85%, respectively. All ApoCell preparations showed an in vitro significant tolerogenic effect upon interaction with dendritic cells. The overall incidence of acute grades II to IV GVHD was 23%, whereas among those receiving the 2 higher doses (n = 6), the rate was 0%. These results suggest that a single infusion of donor ApoCell in HLA-matched allogeneic HSCT is a safe and potentially effective prophylaxis for acute GVHD occurring after myeloablative conditioning. No dose limiting toxicity was observed. (Clinicaltrials.gov no. NCT00524784).     

Graft-Versus-Host Disease and Survival after Cord Blood Transplantation for Acute Leukemia: A Comparison of Japanese versus White Populations

An earlier report identified higher risks of acute and chronic graft-versus-host disease (GVHD) in White children compared with the Japanese after HLA-matched sibling transplantations. The current analysis explored whether racial differences are associated with GVHD risks after unrelated umbilical cord blood transplantation. Included are patients of Japanese descent (n = 257) and Whites (n = 260; 168 of 260 received antithymocyte globulin [ATG]). Transplants were performed in the United States or Japan between 2000 and 2009; patients were aged 16 years or younger, had acute leukemia, were in complete remission, and received a myeloablative conditioning regimen. The median ages of the Japanese and Whites who received ATG were younger at 5 years compared with 8 years for Whites who did not receive ATG. In all groups most transplants were mismatched at 1 or 2 HLA loci. Multivariate analysis found no differences in risks of acute GVHD between the Japanese and Whites. However, chronic GVHD was higher in Whites who did not receive ATG compared with the Japanese (hazard ratio, 2.16; P < .001), and treatment-related mortality was higher in Whites who received ATG compared with the Japanese (relative risk, 1.81; P = .01). Nevertheless, there were no significant differences in overall survival between the 3 groups.     

CD34 Selected Cells for the Treatment of Poor Graft Function after Allogeneic Stem Cell Transplantation

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 × 10⁶/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.     

Reduced-Intensity Allogeneic Transplantation Using Alemtuzumab from HLA-Matched Related,Unrelated, or Haploidentical Related Donors for Patients with Hematologic Malignancies

We present a comparative study on 124 patients with hematologic malignancies who had undergone reduced-intensity conditioning and then received a transplant from an HLA-matched related (MRD), an HLA-matched unrelated (MUD), or an HLA-haploidentical related (HAPLO) donor. The conditioning regimen, which consisted of fludarabine, melphalan or busulfan, and alemtuzumab was administered to patients with lymphoid (n = 62) or myeloid disease (n = 62). Mycophenolate mofetil was used as prophylaxis for graft-versus-host disease (GVHD), and 38, 58, and 33 patients received transplants from MRD, MUD, and HAPLO donors, respectively. Only 2 patients experienced primary graft failure (GF) after melphalan-based regimen, whereas 8 of the 17 patients who received a transplant from HAPLO donors experienced a primary GF after busulfan-based regimen. The cumulative incidence of grade III to IV acute GVHD in engrafted patients who had received transplants from MRD, MUD, or HAPLO donors was 3%, 11%, and 27%, respectively, and the 2-year overall survival (OS) rates were 51%, 22%, and 23%, respectively. According to multivariate analysis, transplantation from either MUD or HAPLO donors compared with MRD were adverse factors that affected the OS (P = .006 and P = .002, respectively). In conclusion, the reduced-intensity regimen that included fludarabine, busulfan, or melphalan and alemtuzumab using only mycophenolate mofetil as the GVHD prophylaxis conferred favorable outcomes in the MRD group but lower survival rates in the MUD and HAPLO groups. The busulfan-based regimen led to a high incidence of GF in the HAPLO group, suggesting the need for modification or intensification of immunosuppression.     

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

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

Pilot Study of Prophylactic Ex Vivo Costimulated Donor Leukocyte Infusion After Reduced-Intensity Conditioned Allogeneic Stem Cell Transplantation

Donor leukocyte infusion (DLI) can induce potent graft-versus-leukemia (GVL) activity in patients with relapsed hematologic malignancies after allogeneic hematopoietic stem cell transplantation (HSCT). Unfortunately, except in patients with chronic-phase chronic myelogenous leukemia, responses to DLI have been disappointing. GVL induction is likely to be most effective in the setting of minimal residual disease. Prevention of relapse through the provision of prophylactic DLI to high-risk patients may improve the outcome of allogeneic HSCT. We previously reported that ex vivo costimulated T cell infusion of activated DLI (aDLI) as treatment for relapse is safe and has potent GVL effects. We hypothesized that prophylactic aDLI can be given safely and prevent relapse in high-risk patients after allogeneic HSCT. Eighteen patients with acute myeolgenous leukemia (n = 14), acute lymphoblastic leukemia (n = 3), or myelodysplastic syndrome (n = 1) underwent allogeneic HSCT after a reduced-intensity conditioning (RIC) regimen with alemtuzumab, fludarabine, and busulfan. Graft-versus-host-disease (GVHD) prophylaxis consisted of tacrolimus and methotrexate with a planned early and rapid taper of tacrolimus. Patients without GVHD, off immune suppression, and in remission received aDLI at a dose of 1 × 10⁷ CD3⁺ cells/kg (aDLI 1) at day +120, followed by a second infusion of 1 × 10⁸ CD3 cells/kg (aDLI 2) at day +180. At a median follow-up of 58 months, 5 of the 18 patients (28%) were alive, and 4 patients were in remission. Eleven patients (65%) relapsed, at a median time of 191 days. Twelve of the 18 patients received at least one aDLI, and 6 of these 12 patients also received aDLI 2. Six patients did not receive any aDLI owing to early relapse (n = 2), protocol ineligibility (n = 1), or GVHD (n = 3). Only 2 of the 12 patients who received aDLI 1 developed GVHD. Two out of the 12 patients remain in remission at the time of this report. Disease recurrence was the cause of death in 10 of the 13 patients (77%) who died. Our data indicate that prophylactic ex vivo costimulated CD3/CD28 DLI is safe, feasible, and not associated with significant GVHD. Relapse remains the major cause of treatment failure after RIC HSCT even with rapid withdrawal of immune suppression and the use of prophylactic aDLI, and better strategies to prevent relapse are needed.     

Antithymocyte Globulin before Allogeneic Stem Cell Transplantation for Progressive Myelodysplastic Syndrome: A Study from the French Society of Bone Marrow Transplantation and Cellular Therapy

We investigated the impact of rabbit antithymocyte globulins (ATG) on patient outcomes after allogeneic stem cell transplantation (allo-SCT) for progressive myelodysplastic syndrome (MDS). Of the 242 consecutive patients who underwent allo-SCT for progressive MDS between October 1999 and December 2009, 93 received ATG (ATG group) at the median dose of 5 mg/kg, whereas 149 patients did not (no-ATG group). Donors were sibling (n = 153) or HLA-matched unrelated (n = 89). Patients received blood (n = 90) or marrow (n = 152) grafts after either myeloablative (n = 109) or reduced-intensity (n = 133) conditioning. Three-year overall and event-free survival, nonrelapse mortality, relapse, and chronic graft-versus-host disease (GVHD) development were not significantly different between the 2 groups. In contrast, acute grade II to IV GVHD occurred more often in the no-ATG group (55% of the patients) than in the ATG group (27%, P < .0001). Similar results were observed with acute grade III to IV GVHD (28% and 14% in the no-ATG group and ATG group, respectively; P = .009). In multivariate analysis, after adjustment with propensity score, the absence of ATG was the strongest parameter associated with an increased risk of acute grade II to IV GVHD (hazard ratio, 2.13; 95% confidence interval, 1.35 to 3.37; P = .001]. ATG had no impact on overall and event-free survival or cumulative incidence of the relapse. In conclusion, the addition of ATG to allo-SCT conditioning did not increase the incidence of relapse of patients with progressive MDS. The incidence of acute GVHD was decreased without compromising outcomes.     

Outcomes of Hematopoietic Cell Transplantation in Adult Patients with Acquired Aplastic Anemia Using Intermediate-Dose Alemtuzumab-Based Conditioning

Graft-versus-host disease (GVHD) has no therapeutic benefit after hematopoietic cell transplantation (HCT) for patients with acquired aplastic anemia (AA), and its prevention is highly desirable. We designed a conditioning regimen using an intermediate dose of alemtuzumab (50 to 60 mg) and describe our institutional experience of 41 patients who underwent HCT for AA. The median age at HCT was 37 years (range, 17 to 59). The conditioning regimen was high-dose cyclophosphamide (n = 9) or fludarabine based (n = 32). Additional GVHD prophylaxis was with cyclosporine. With a median follow-up of 3.6 years, overall survival at 3 years was 85%. Survival in patients <40 years and ≥40 years was 96% and 67%, respectively (P = .04). Graft failure occurred in 4 (10%) patients; 2 primary and 2 secondary. The cumulative incidences of acute (grades 1 to 2) and chronic GVHD were 27% and 15%, respectively. No patients developed grade 3 to 4 acute GVHD or severe chronic GVHD. The following viral complications were frequent: cytomegalovirus reactivation (79%), herpes simplex (18%), varicella zoster (25%), and BK virus hemorrhagic cystitis (8%). The majority of patients had no significant long-term health issues. This intermediate-dose alemtuzumab-based conditioning regimen results in excellent survival with a favorable impact on GVHD and long-term health outcomes, but close monitoring for viral complications is important.     

Graft Cryopreservation Does Not Impact Overall Survival after Allogeneic Hematopoietic Cell Transplantation Using Post-Transplantation Cyclophosphamide for Graft-versus-Host Disease Prophylaxis

The COVID-19 pandemic has created significant barriers to timely donor evaluation, cell collection, and graft transport for allogeneic hematopoietic stem cell transplantation (allo-HCT). To ensure availability of donor cells on the scheduled date of infusion, many sites now collect cryopreserved grafts before the start of pretransplantation conditioning. Post-transplantation cyclophosphamide (ptCY) is an increasingly used approach for graft-versus-host disease (GVHD) prophylaxis, but the impact of graft cryopreservation on the outcomes of allo-HCT using ptCY is not known. Using the Center for International Blood and Marrow Transplant Research (CIBMTR) database, we compared the outcomes of HCT using cryopreserved versus fresh grafts in patients undergoing HCT for hematologic malignancy with ptCY. We analyzed 274 patients with hematologic malignancy undergoing allo-HCT between 2013 and 2018 with cryopreserved grafts and ptCY. Eighteen patients received bone marrow grafts and 256 received peripheral blood stem cell grafts. These patients were matched for age, graft type, disease risk index (DRI), and propensity score with 1080 patients who underwent allo-HCT with fresh grafts. The propensity score, which is an assessment of the likelihood of receiving a fresh graft versus a cryopreserved graft, was calculated using logistic regression to account for the following: disease histology, Karnofsky Performance Score (KPS), HCT Comorbidity Index, conditioning regimen intensity, donor type, and recipient race. The primary endpoint was overall survival (OS). Secondary endpoints included acute and chronic graft-versus-host disease (GVHD), non-relapse mortality (NRM), relapse/progression and disease-free survival (DFS). Because of multiple comparisons, only P values <.01 were considered statistically significant. The 2 cohorts (cryopreserved and fresh) were similar in terms of patient age, KPS, diagnosis, DRI, HCT-CI, donor/graft source, and conditioning intensity. One-year probabilities of OS were 71.1% (95% confidence interval [CI], 68.3% to 73.8%) with fresh grafts and 70.3% (95% CI, 64.6% to 75.7%) with cryopreserved grafts (P = .81). Corresponding probabilities of OS at 2 years were 60.6% (95% CI, 57.3% to 63.8%) and 58.7% (95% CI, 51.9% to 65.4%) (P = .62). In matched-pair regression analysis, graft cryopreservation was not associated with a significantly higher risk of mortality (hazard ratio [HR] for cryopreserved versus fresh, 1.05; 95% CI, .86 to 1.29; P = .60). Similarly, rates of neutrophil recovery (HR, .91; 95% CI, .80 to 1.02; P = .12), platelet recovery (HR, .88; 95% CI, .78 to 1.00; P = .05), grade III-IV acute GVHD (HR, .78; 95% CI, .50 to 1.22; P = .27), NRM (HR, 1.16; 95% CI, .86 to 1.55; P = .32) and relapse/progression (HR, 1.21; 95% CI, .97 to 1.50; P = .09) were similar with cryopreserved grafts versus fresh grafts. There were somewhat lower rates of chronic GVHD (HR, 78; 95% CI, .61 to .99; P = .04) and DFS (HR for treatment failure, 1.19; 95% CI, 1.01 to 1.29; P = .04) with graft cryopreservation that were of marginal statistical significance after adjusting for multiple comparisons. Overall, our data indicate that graft cryopreservation does not significantly delay hematopoietic recovery, increase the risk of acute GVHD or NRM, or decrease OS after allo-HCT using ptCY.     

Risk Factors for Graft-versus-Host Disease in Haploidentical Hematopoietic Cell Transplantation Using Post-Transplant Cyclophosphamide

Post-transplant cyclophosphamide (PTCy) has significantly increased the successful use of haploidentical donors with a relatively low incidence of graft-versus-host disease (GVHD). Given its increasing use, we sought to determine risk factors for GVHD after haploidentical hematopoietic cell transplantation (haplo-HCT) using PTCy. Data from the Center for International Blood and Marrow Transplant Research on adult patients with acute myeloid leukemia, acute lymphoblastic leukemia, myelodysplastic syndrome, or chronic myeloid leukemia who underwent PTCy-based haplo-HCT (2013 to 2016) were analyzed and categorized into 4 groups based on myeloablative (MA) or reduced-intensity conditioning (RIC) and bone marrow (BM) or peripheral blood (PB) graft source. In total, 646 patients were identified (MA-BM = 79, MA-PB = 183, RIC-BM = 192, RIC-PB = 192). The incidence of grade 2 to 4 acute GVHD at 6 months was highest in MA-PB (44%), followed by RIC-PB (36%), MA-BM (36%), and RIC-BM (30%) (P = .002). The incidence of chronic GVHD at 1 year was 40%, 34%, 24%, and 20%, respectively (P < .001). In multivariable analysis, there was no impact of stem cell source or conditioning regimen on grade 2 to 4 acute GVHD; however, older donor age (30 to 49 versus <29 years) was significantly associated with higher rates of grade 2 to 4 acute GVHD (hazard ratio [HR], 1.53; 95% confidence interval [CI], 1.11 to 2.12; P = .01). In contrast, PB compared to BM as a stem cell source was a significant risk factor for the development of chronic GVHD (HR, 1.70; 95% CI, 1.11 to 2.62; P = .01) in the RIC setting. There were no differences in relapse or overall survival between groups. Donor age and graft source are risk factors for acute and chronic GVHD, respectively, after PTCy-based haplo-HCT. Our results indicate that in RIC haplo-HCT, the risk of chronic GVHD is higher with PB stem cells, without any difference in relapse or overall survival.     

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

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

Fludarabine and Total-Body Irradiation Conditioning before Ablative Haploidentical Transplantation: Long-Term Safety and Efficacy

Although myeloablative conditioning (MAC) before haploidentical donor transplant (HIDT) with post-transplant cyclophosphamide is being increasingly used, the optimal preparative regimen remains unclear. In our initial trial, the feasibility of HIDT following a MAC preparative regimen using fludarabine and 12 Gy of total-body irradiation was demonstrated in 30 patients. We now present long-term outcome results, including an additional 52 patients, now with 47 months (16 to 96) median follow-up. Median patient age was 42 (19 to 61) years. The most common diagnoses were acute myelogenous leukemia (51%) and acute lymphoblastic leukemia (33%), and 39% had a high/very high disease risk index (DRI). Engraftment was universal with no cases of primary or secondary graft failure. Grade 3 to 4 acute graft-versus-host disease (GVHD) and moderate to severe chronic GVHD occurred in 17% and 23%, respectively. Nonrelapse mortality (NRM) was 7% at 1 year and 13% at 4 years. Estimated 4-year overall survival (OS), disease-free survival, and cumulative incidence of relapse (CIR) were 67%, 60%, and 27%, respectively. CIR was significantly higher in patients with high/very high- versus low/intermediate-risk DRI (38% versus 20%, P= .032), which led to inferior 4-year OS (50% versus 77%, P = .001). Median time to systemic immunosuppressive therapy (IST) discontinuation was 7.8 months, with 84% of patients off IST at 2 years post-transplant. Current GHVD-free, relapse-free survival (CGRFS) at 2, 3, and 4 years was 60%, 57%, and 60%, respectively. This approach to MAC HIDT results in universal engraftment; low rates of NRM, infection, and clinically significant GVHD; and relatively rapid IST discontinuation, resulting in high rates of CGRFS and survival.     

HLA-Haploidentical Hematopoietic Cell Transplantation for Treatment of Nonmalignant Diseases Using Nonmyeloablative Conditioning and Post-Transplant Cyclophosphamide

Allogeneic hematopoietic cell transplant (HCT) is often the only curative therapy for patients with nonmalignant diseases; however, many patients do not have an HLA-matched donor. Historically, poor survival has been seen after HLA-haploidentical HCT because of poor immune reconstitution, increased infections, graft-versus-host disease (GVHD), and graft failure. Encouraging results have been reported using a nonmyeloablative T cell–replete HLA-haploidentical transplant approach in patients with hematologic malignancies. Here we report the outcomes of 23 patients with various nonmalignant diseases using a similar approach. Patients received HLA-haploidentical bone marrow (n = 17) or granulocyte colony-stimulating factor–mobilized peripheral blood stem cell (n = 6) grafts after conditioning with cyclophosphamide 50 mg/kg, fludarabine 150 mg/m², and 2 or 4 Gy total body irradiation. Postgrafting immunosuppression consisted of cyclophosphamide, mycophenolate mofetil, tacrolimus, ± sirolimus. Median patient age at HCT was 10.8 years. Day 100 transplant-related mortality (TRM) was 0%. Two patients died at later time points, 1 from intracranial hemorrhage/disseminated fungal infection in the setting of graft failure and 1 from infection/GVHD. The estimated probabilities of grades II to IV and III to IV acute GVHD at day 100 and 2-year National Institutes of Health consensus chronic GVHD were 78%, 26%, and 42%, respectively. With a median follow-up of 2.5 years, the 2-year overall and event-free rates of survival were 91% and 78%, respectively. These results are encouraging and demonstrate favorable disease-specific lineage engraftment with low TRM in patients with nonmalignant diseases using nonmyeloablative conditioning followed by T cell–replete HLA-haploidentical grafts. However, additional strategies are needed for GVHD prevention to make this a viable treatment approach for patients with nonmalignant diseases.     

Unrelated Donor Transplant Recipients Given Thymoglobuline Have Superior GRFS When Compared to Matched Related Donor Recipients Undergoing Transplantation without ATG

Recipients of allogeneic hematopoietic stem cell transplantation (HSCT) from unrelated donors (URDs) and mismatched related donors (MMRDs) typically have a higher incidence of acute and chronic graft-versus-host disease (GVHD) compared with matched related donors (MRDs). Anti-T-cell globulins (ATGs) are often used to reduce GVHD in these recipients. We report the outcomes of 211 adult peripheral blood stem cell transplant recipients with myeloid malignancies who received a standardized transplant protocol, in which ATG (Thymoglobuline 4.5 mg/kg) was administered to recipients of URD and MMRD (n = 147) but not MRD (n = 64) transplant. For all patients, incidence of acute GVHD grades 2 to 4 was 21.4%, and chronic GVHD was 35.0%. Two-year overall survival was 63.2% (95% confidence interval, 55.8% to 71.5%), relapse-free survival was 55.3% (47.4% to 64.6%), and GVHD-free, relapse-free survival (GRFS) was 30.7% (23.2% to 40.8%). There were no differences between recipients of MRDs and other donors in relapse, nonrelapse mortality, and overall and relapse-free survival. However, compared with MRD, recipients from URDs and MMRDs had reduced moderate to severe chronic GVHD (10.4% versus 30.1%, P= .002), less chronic GVHD requiring systemic therapy (19.4% versus 38.9%, P = .006), and superior 2-year GRFS (35.5% versus 20.0%, P = .003). In this retrospective review of nonrandomized transplant groups, outcomes of HSCT performed using an URD with ATG during conditioning were superior to transplant from an MRD without ATG. The addition of Thymoglobuline to conditioning in HSCT from MRD should be further examined in prospective trials.