Margaret L. MacMillan

Relapse risk after umbilical cord blood transplantation: enhanced graft-versus-leukemia effect in recipients of 2 units

Umbilical cord blood (UCB) transplantation is potentially curative for acute leukemia. This analysis was performed to identify risk factors associated with leukemia relapse following myeloablative UCB transplantation. Acute leukemia patients (n = 177; 88 with acute lymphoblastic leukemia and 89 with acute myeloid leukemia) were treated at a single center. Patients received a UCB graft composed of either 1 (47%) or 2 (53%) partially human leukocyte antigen (HLA)-matched unit(s). Conditioning was with cyclophosphamide and total body irradiation with or without fludarabine. The incidence of relapse was 26% (95% confidence interval [CI], 19%-33%). In multivariate analysis, relapse was higher in advanced disease patients (> or = third complete remission [CR3]; relative risk [RR], 3.6; P < .01), with a trend toward less relapse in recipients of 2 UCB units (RR = 0.6; P = .07). However, relapse was lower for CR1-2 patients who received 2 UCB units (RR 0.5; P < .03). Leukemia-free survival was 40% (95% CI, 30%-51%) and 51% (95% CI, 41%-62%) for single- and double-unit recipients, respectively (P = .35). Although it is known that transplantation in CR1 and CR2 is associated with less relapse risk, this analysis reveals an enhanced graft-versus-leukemia effect in acute leukemia patients after transplantation with 2 partially HLA-matched UCB units. This trial was registered at http://clinicaltrials.gov as NCT00309842.

Transplantation of ex-vivo culture-expanded parental haploidentical mesenchymal stem cells to promote engraftment in pediatric recipients of unrelated donor umbilical cord blood: results of a phase I–II clinical trial

Suboptimal neutrophil and platelet recovery after unrelated donor umbilical cord blood transplantation (UCBT) may be due in part to an impaired microenvironment after intensive chemoradiotherapy. In an attempt to speed hematopoietic recovery, 15 pediatric patients with high-risk acute leukemia were enrolled on a single-institution phase I–II clinical trial in which ex-vivo culture-expanded MSCs from haploidentical parental donors were infused at the time of UCBT. Eight patients received MSCs on day 0, with three patients having a second dose infused on day 21. No serious adverse events were observed with any MSC infusion. All eight evaluable patients achieved neutrophil engraftment at a median of 19 days. Probability of platelet engraftment was 75%, at a median of 53 days. With a median follow-up of 6.8 years, five patients remain alive and disease free. The results of this pilot study show that infusion of ex-vivo culture-expanded haploidentical MSCs into unrelated pediatric UCBT recipients can be performed safely. This encouraging safety profile with haploidentical MSCs supports the investigation of unrelated ‘off the shelf’ allogeneic HLA-mismatched MSC products.

Acute graft-versus-host disease after unrelated donor umbilical cord blood transplantation : analysis of risk factors

Acute graft-versus-host disease (GVHD) occurs less frequently after umbilical cord blood transplantation (UCBT). More recent investigations include the use of 2 partially human leukocyte antigen (HLA)-matched UCB units, or double UCB graft, to meet the minimum cell-dose requirement. The purpose of this analysis was to assess the relative risk of acute GVHD in 265 consecutive patients receiving transplants with UCB graft composed of 1 (n = 80) or 2 (n = 185) units. The incidence of grade III-IV acute GVHD was similar between cohorts. However, the incidence of grade II-IV acute GVHD was higher among double UCBT recipients (58 vs 39%, P < .01). Three risk factors for grade II-IV acute GVHD were identified in multiple regression analysis: use of 2 UCB units, use of nonmyeloablative conditioning, and absence of antithymocyte globulin in the conditioning regimen. Transplantation-related mortality (TRM) at 1 year, however, was significantly lower after double UCBT (24 vs 39%, P = .02) even if recipients had grade II-IV acute GVHD (20 vs 39%, P = .05). These data suggest that, despite a higher incidence of grade II acute GVHD in recipients of 2 partially HLA-matched UCB units, there is no adverse effect on TRM. This study is registered at (http://www.clinicaltrials.gov) under the identifiers NCT00305682 and NCT00309842.

Composite end point of graft-versus-host disease-free, relapse-free survival after allogeneic hematopoietic cell transplantation

The success of allogeneic hematopoietic cell transplantation (HCT) is typically assessed as individual complications, including graft-versus-host disease (GVHD), relapse, or death, yet no one factor can completely characterize cure without ongoing morbidity. We examined a novel composite end point of GVHD-free/relapse-free survival (GRFS) in which events include grade 3-4 acute GVHD, systemic therapy-requiring chronic GVHD, relapse, or death in the first post-HCT year. In 907 consecutive University of Minnesota allogeneic HCT recipients (2000-2012), 1-year GRFS was 31% (95% confidence interval [CI] 28-34). Regression analyses showed age, disease risk, and donor type significantly influencing GRFS. Adults age 21+ had 2-fold worse GRFS vs children; GRFS did not differ beyond age 21. Adjusted for conditioning intensity, stem cell source, disease risk, age, and transplant year, HLA-matched sibling donor marrow resulted in the best GRFS (51%, 95% CI 46-66), whereas HLA-matched sibling donor peripheral blood stem cells were significantly worse (25%, 95% CI 20-30, P = .01). GRFS after umbilical cord blood transplants and marrow from matched unrelated donors were similar (31%, 95% CI 27-35 and 32%, 95% CI 22-42, respectively). Because GRFS measures freedom from ongoing morbidity and represents ideal HCT recovery, GRFS has value as a novel end point for benchmarking new therapies.

Umbilical cord blood-derived T regulatory cells to prevent GVHD: kinetics, toxicity profile and clinical effect

We studied the safety and clinical outcomes of patients treated with umbilical cord blood (UCB)-derived regulatory T cells (Tregs) that expanded in cultures stimulated with K562 cells modified to express the high-affinity Fc receptor (CD64) and CD86, the natural ligand of CD28 (KT64/86). Eleven patients were treated with Treg doses from 3-100 × 10(6) Treg/kg. The median proportion of CD4(+)FoxP3(+)CD127(-) in the infused product was 87% (range, 78%-95%), and we observed no dose-limiting infusional adverse events. Clinical outcomes were compared with contemporary controls (n = 22) who received the same conditioning regimen with sirolimus and mycophenolate mofetil immune suppression. The incidence of grade II-IV acute graft-versus-host disease (GVHD) at 100 days was 9% (95% confidence interval [CI], 0-25) vs 45% (95% CI, 24-67) in controls (P = .05). Chronic GVHD at 1 year was zero in Tregs and 14% in controls. Hematopoietic recovery and chimerism, cumulative density of infections, nonrelapse mortality, relapse, and disease-free survival were similar in the Treg recipients and controls. KT64/86-expanded UCB Tregs were safe and resulted in low risk of acute GVHD.

Haematopoeitic cell transplantation for Fanconi anaemia - When and how?

Allogeneic haematopoietic cell transplantation (HCT) remains the only treatment that can correct the haematological manifestations in patients with Fanconi anaemia. Over the last two decades, sequential changes to the approach to HCT have resulted in reduced regimen‐related toxicity, superior engraftment and less graft‐versus‐host disease (GVHD), resulting in improved survival. The two pivotal changes that most influenced these improvements were the addition of fludarabine to the preparative regimen to augment engraftment, and the use of T cell depletion to reduce GVHD. With these improved HCT outcomes, indications for HCT are quite consistent regardless of donor source. Emphasis is now being placed on developing HCT regimens that will improve quality of life by reducing late effects, particularly the risk of malignancy, sterility and endocrinopathies. This paper will review the unique challenges of HCT in FA patients, with particular emphasis on the timing and approach to HCT.

The best endpoint for acute GVHD treatment trials

The optimal primary endpoint for acute graft-versus-host disease (GVHD) therapeutic trials has not been established. In a retrospective analysis, we examined the response of 864 patients who received prednisone 60 mg/m(2)/d for 14 days, followed by an 8-week taper, as initial therapy for acute GVHD from 1990-2007 at the University of Minnesota. Patients received grafts of human leukocyte antigen-matched sibling bone marrow (BM) or peripheral blood (PB; n = 315), partially matched sibling BM or PB (n = 24), unrelated donor BM or PB (n = 313), single (n = 89) or double (n = 123) umbilical cord blood. Day 28 responses were similar to day 56 responses and better than day 14 responses in predicting transplantation-related mortality (TRM). In multiple regression analysis, patients with no response at day 28 were 2.78 times (95% CI, 2.17-3.56 times; P < .001) more likely to experience TRM before 2 years than patients with a response. Other factors associated with significantly worse 2-year TRM include older age, high-risk disease, severe GVHD, and partially matched related BM/PB. No other differences in response by donor source were observed. These data suggest that day 28 is the best early endpoint for acute GVHD therapeutic trials in predicting 2-year TRM.

New classification of chronic GVHD: added clarity from the consensus diagnoses

The Diagnosis and Staging Working Group of the NIH Consensus Development Project on Criteria for Clinical Trials in chronic GVHD (CGVHD) recently proposed criteria for diagnosis and assessment of overall CGVHD severity. We retrospectively reviewed 54 consecutive patients diagnosed with CGVHD between January 2002 and December 2005 after sibling donor transplant to assess the applicability of the new criteria in prognosticating survival and transplant-related mortality (TRM). A total of 8 patients (15%) were reclassified as late onset/persistent or recurrent acute GVHD (late aGVHD), 15 (28%) had overlap syndrome and 31 (57%) had classic CGVHD. Three-year overall survival was worse in patients with late aGVHD (3-year probability 25% (95% CI 4–56%)) followed by overlap syndrome (3-year probability 87% (95% CI 56–96%)) and CGVHD (3-year probability 75% (95% CI 54–87%)); P=0.001. Among patients with overlap syndrome and CGVHD, a trend towards worse survival was seen in patients with severe disease (3-year probability 57.3% (95% CI 21–82%)) as compared to mild+moderate disease (3-year probability 85.1% (95% CI 68–94)); P=0.1. This analysis, undertaken in a contemporary cohort of related donor recipients, indicates that the consensus guidelines are applicable to this population of CGVHD patients.

Tacrolimus/sirolimus vs tacrolimus/methotrexate as GVHD prophylaxis after matched, related donor allogeneic HCT

Grades 2-4 acute graft-versus-host disease (GVHD) occurs in approximately 35% of matched, related donor (MRD) allogeneic hematopoietic cell transplantation (HCT) recipients. We sought to determine if the combination of tacrolimus and sirolimus (Tac/Sir) was more effective than tacrolimus and methotrexate (Tac/Mtx) in preventing acute GVHD and early mortality after allogeneic MRD HCT in a phase 3, multicenter trial. The primary end point of the trial was to compare 114-day grades 2-4 acute GVHD-free survival using an intention-to-treat analysis of 304 randomized subjects. There was no difference in the probability of day 114 grades 2-4 acute GVHD-free survival (67% vs 62%, P = .38). Grades 2-4 GVHD was similar in the Tac/Sir and Tac/Mtx arms (26% vs 34%, P = .48). Neutrophil and platelet engraftment were more rapid in the Tac/Sir arm (14 vs 16 days, P < .001; 16 vs 19 days, P = .03). Oropharyngeal mucositis was less severe in the Tac/Sir arm (peak Oral Mucositis Assessment Scale score 0.70 vs 0.96, P < .001), but otherwise toxicity was similar. Chronic GVHD, relapse-free survival, and overall survival at 2 years were no different between study arms (53% vs 45%, P = .06; 53% vs 54%, P = .77; and 59% vs 63%, P = .36). Based on similar long-term outcomes, more rapid engraftment, and less oropharyngeal mucositis, the combination of Tac/Sir is an acceptable alternative to Tac/Mtx after MRD HCT. This study was funded by the National Heart, Lung, and Blood Institute and the National Cancer Institute; and the trial was registered at www.clinicaltrials.gov as #NCT00406393.

Successful engraftment without radiation after fludarabine-based regimen in Fanconi anemia patients undergoing genotypically identical donor hematopoietic cell transplantation†

To potentially reduce late effects of malignancy, chronic graft‐versus‐host disease (GVHD), endocrinopathy, and infertility in patients with Fanconi anemia (FA) undergoing HLA‐matched related donor hematopoietic cell transplantation (HCT), we developed a regimen using fludarabine (FLU), cyclophosphamide (CY), and anti‐thymocyte globulin (ATG) followed by infusion of T‐cell depleted (TCD) bone marrow (BM) or unmanipulated umbilical cord blood (UCB). GVHD prophylaxis consisted of cyclosporine and short course methylprednisolone.