Original Article

Bone Marrow Transplantation (2015) 50, 367–374; doi:10.1038/bmt.2014.269; published online 1 December 2014

Lymphoma

Comparison of non-myeloablative conditioning regimens for lymphoproliferative disorders

S Hong1,2, J Le-Rademacher2,3, A Artz4, P L McCarthy5, B R Logan2,3 and M C Pasquini2

  1. 1Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, USA
  2. 2Center for International Blood and Marrow Transplant Research, Medical College of Wisconsin, Milwaukee, WI, USA
  3. 3Division of Biostatistics, Institute of Health and Society, Medical College of Wisconsin, Milwaukee, WI, USA
  4. 4Department of Medicine, University of Chicago, Chicago, IL, USA
  5. 5Department of Medicine, Roswell Park Cancer Institute, Buffalo, NY, USA

Correspondence: Dr MC Pasquini, Center for International Blood and Marrow Transplant Research, Department of Medicine, Medical College of Wisconsin, 9200 West Wisconsin Avenue, Suite C5500, Milwaukee, WI 53226, USA. E-mail: mpasquini@mcw.edu

Received 15 August 2014; Revised 24 September 2014; Accepted 25 September 2014
Advance online publication 1 December 2014

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Abstract

Hematopoietic cell transplantation (HCT) with non-myeloablative (NMA) conditioning for lymphoproliferative diseases (LD) includes fludarabine with and without low-dose TBI. Transplant outcomes were compared among patients aged greater than or equal to40 years with LD who received a HCT with TBI (N=382) or no-TBI (N=515) NMA from 2001 to 2011. The groups were comparable except for donor, graft, prophylaxis for GVHD, disease status and year of HCT. Cumulative incidences of grades II–IV GVHD at 100 days were 29% and 20% (P=0.001) and of chronic GVHD at 1 year were 54% and 44% (P=0.004) for TBI and no-TBI, respectively. Multivariate analysis of progression/relapse, treatment failure and mortality showed no outcome differences by conditioning. Full donor chimerism at day 100 was observed in 82% vs 64% in the TBI and no-TBI groups, respectively (P=0.006). Subsets of the four most common conditioning/GVHD prophylaxis combinations demonstrated higher rates of grades II–IV acute (P<0.001) and chronic GVHD (P<0.001) among recipients of TBI–mycophenolate mofetil (MMF) compared with other combinations. TBI-based NMA conditioning induces faster full donor chimerism, but overall survival outcomes are comparable to no-TBI regimens. Combinations of TBI and MMF are associated with higher rates of GVHD without impact on survival outcomes in patients with LD.

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Introduction

Non-myeloablative (NMA) conditioning regimens for allogeneic hematopoietic cell transplantation (HCT) are mainly immunosuppressive and less toxic to the recipients’ stem cells. NMA regimens allowed options of HCTs for patients who were traditionally not eligible due to advanced age or comorbidities.1, 2, 3 In NMA conditioning, low-dose TBI (200cGy) is utilized for immune ablation to aid achievement of donor chimerism.4 The combination of TBI and fludarabine (Flu) is a common NMA regimen, which is most commonly combined with GVHD prophylaxis using mycophenolate mofetil (MMF) and a calcineurin inhibitor (CNI) as pioneered by the Seattle group.3, 4

Transplants for lymphoproliferative diseases (LD) commonly use NMA regimens as the indolent nature of some of these diseases allow for disease control by the allograft or graft-vs-tumor effect. Also, NMA regimens help minimize toxicity for patients with prior autologous HCTs that are frequent in the treatment of LD. CLL, mantle cell lymphoma and follicular lymphoma in particular are indications, whereas NMA is the most common conditioning intensity used.5 Since the inception of TBI-based NMA regimens, several other regimens have been used that excluded TBI and added chemotherapeutic agents commonly used to treated LD, such as cyclophosphamide (Cy), rituximab and Flu among others.6, 7

Nevertheless, no studies have directly addressed whether TBI-based (200cGy) NMA conditioning regimens result in different outcomes compared with no-TBI regimens for LD.8, 9 Meta-analyses comparing different NMA regimens both with and without TBI showed conflicting results, including incidence of acute and chronic GVHD, engraftment and survival.10, 11, 12

The current study explored the differences in HCT outcomes using a common immune ablation method (TBI) vs disease-specific regimens (no-TBI) for LD.

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Materials and methods

Data sources

The Center for International Blood and Marrow Transplant Research (CIBMTR) is a research working group of >450 transplantation centers worldwide that contribute detailed data on consecutive HCT to a Statistical Center at the Medical College of Wisconsin in Milwaukee and the National Marrow Donor Program Coordinating Center in Minneapolis.5

Study population

Eligibility for this study includes patients aged greater than or equal to40 years with LD and reported to the CIBMTR after the first allogeneic transplantation with NMA conditioning between 2001 and 2011. Patients aged <40 years were excluded as they represented <10% of the population. Regimens in the myeloablative or reduced intensity range were excluded from this analysis. LD includes CLL or small-lymphocytic lymphoma, Hodgkin lymphoma and non-Hodgkin lymphoma. Recipients of cord blood grafts, ex vivo T-cell depletion, syngeneic donors and cases with insufficient follow-up (less than or equal to100 days, n=59) were excluded. For HCTs from unrelated donor (URD), HLA matching at HLA-A, B, C and DRB1 were included in the well-matched category or 8/8 match. Recipients of at least one antigen or allele mismatched were also eligible for the study (partially matched or 7/8 match). NMA conditioning regimen was defined as TBIless than or equal to200cGY.13 Furthermore, conditioning regimens were separated in two Flu-based cohorts, with or without TBI. Overall, completeness indices of follow-up at 3 years was 96% for the TBI and 90% for the no-TBI cohorts, respectively.14, 15

Diseases were grouped as low-grade, intermediate-grade and other diseases. Low-grade diseases included CLL, low- or intermediate-grade follicular lymphoma, marginal zone lymphoma and diffuse small cleaved cell lymphoma. Intermediate-grade diseases included high-grade follicular lymphoma, mantle cell lymphoma, diffuse large B-cell lymphoma and T-cell lymphoma. Other diseases included Hodgkin lymphoma, unknown grade follicular lymphoma, small lymphoplasmacytic lymphoma, mycosis fungoides and other non-Hodgkin lymphoma.

Disease status at transplant defined groups according to disease burden, response to prior therapy and sensitivity to therapy.

Outcomes

Engraftment assessed hematopoietic recovery of neutrophils and platelets following transplant. Neutrophil engraftment was defined as neutrophil recovery greater than or equal to0.5 × 109/L for three consecutive laboratory values. Platelet engraftment was measured at platelet recovery greater than or equal to20 and 50 × 109/L without platelet transfusion for 7 consecutive days on three consecutive laboratory values on different dates. The modified Glucksberg classification was used to define events of grades II–IV and III–IV acute GVHD in the first 100 days post-HCT.16 Death without GVHD was considered a competing risk; incidences of acute and chronic GVHD were calculated. Treatment-related mortality (TRM) was defined as death without progression or relapse.

Donor chimerism analysis from PB or BM source was conducted in between 21and 100 days post-HCT. More than or equal to 90% donor chimerism was considered as full donor chimerism.17, 18 Competing risk for achieving full donor chimerism was defined as subsequent transplant, relapse or progression of primary disease or death without achieving full donor chimerism. Conversely, loss of donor chimerism was defined as <10% donor chimerism. Donor chimerism percentages between 10% and 90% were defined as mixed chimerism. Sorted T-cell and unsorted chimerisms were analyzed separately. For the analysis of temporal achievement of full chimerism, the first day of achieving full donor chimerism was measured.

Statistical analysis

The main comparison for this study was between TBI and no-TBI regimen. Univariate analyses of neutrophil and platelet recovery, TRM, GVHD and relapse or progression were conducted. Covariates for Cox hazard regression multivariate analysis for overall mortality, TRM, acute and chronic GVHD, disease progression and treatment failure were age, disease grouped by grade and histology, sensitivity to therapy prior to HCT, transplant year, history of prior autologous HCTs, Karnofsky Performance Score (KPS) at the time of preparative regimen, use of anti-thymocyte globulin (ATG) and/or campath, use of rituximab before or after HCTs, graft source use and donor type by HLA match status. Interaction test between the main effect and all covariates was performed, and none was identified.

Donor chimerism between days 21 and 100 post HCT was analyzed in years 2008 and 2011, due to the completeness of the data. Median of days to achieve complete donor chimerism was assessed for groups with and without TBI. Then, proportions of patients achieving full donor chimerism were assessed for the three time periods: days 21–45, 46–75, and 76–100. Median donor cell percentage for each time period was also assessed for both sorted T-lymphocyte (lymphoid lineage) and unsorted cell chimerism. If there was no chimerism tested for the time period, then the available value from the previous time period were presumed for cumulative donor chimerism achievement. There were no chimerism discrepancies that could modify the chimerism status, that is, from mixed to full donor chimerism, or from mixed chimerism to loss of chimerism among cases with multiple assessments in a single period.

Practices of NMA regimen often include the same GVHD prophylaxis as a treatment package, making it difficult to test a single component separately. To address this, the most common NMA regimen/GVHD prophylaxis combinations used for CLL, follicular lymphoma and mantle cell lymphoma were identified and compared in a subset analysis. The method of analysis was the same as for the main comparison.

SQL developer (Oracle, Redwood City, CA, USA) and SAS 9.2 (SAS Institute, Cary, NC, USA) were used for the analyses.

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Results

Study population

As in Table 1, both the cohorts were well balanced for age (median age 57 for the TBI vs 56 years for the no-TBI cohorts, P=0.13), sex (male 74% vs 67%, P=0.05), donor sex (61% vs 66%, P=0.16) and time from diagnosis to transplant (median 51 vs 47 months, P=0.31). Recipients of TBI-based regimens were more frequently with performance score (KPS) <90% compared with no-TBI (32% vs 22%, P=0.003). Forty-eight patients (16%) in the TBI cohort and 38 patients (9%) in the no-TBI cohort received autologous transplant(s) prior to the first allogeneic HCTs (P=0.005).


TBI was performed less frequently later in the period (years 2009–2011, 9% vs 11%, P<0.001), included more recipients of URD (62% vs 47%, P<0.001), PBSC (94% vs 85%, P<0.001), less frequently used rituximab in the conditioning (7% vs 40%, P<0.001) and used more frequently CNI- and MMF-based combination of GVHD prophylaxis (87% vs 15%, P<0.001). Furthermore, the TBI cohort had more CMV mismatches (44 vs 38%, P=0.003) and had less cases with sensitivity to prior therapy (48% vs 60%, P<0.001) as well as less cases with CR at the time of preparative regimen (33% vs 25%, P<0.001).

Hematologic recovery

In the TBI cohort, 40% and 60% never dropped neutrophil and platelet counts below the level of engraftment compared with 24% and 43% in the no-TBI group, respectively. Neutrophil recovery by day 28 post HCT was >95% for both the groups (P=0.12). Platelet recovery greater than or equal to20 × 109/L by day 100 were 84% (95% confidence interval (CI), 77–85%) and 92% (95% CI, 88–94%, P=0.03) for the TBI and no-TBI cohorts, respectively. Corresponding incidences of platelet recover greater than or equal to50 × 109/L by day 100 were 79% (95% CI, 70–85%) and 92% (95% CI, 88–95%, P<0.001).

Acute and chronic GVHD

Incidences for grades II–IV acute GVHD at 100 days were 29% (95% CI, 25–34%) and 20% (95% CI, 16–23%, P=0.001) for the TBI and no-TBI groups, respectively (Figure 1a). Corresponding incidences of grade III–IV acute GVHD were 13% (95% CI, 10–17%) and 7% (95% CI, 5–9% P=0.002). Multivariate analysis of grade II–IV acute GVHD confirmed a higher incidence with TBI (hazard ratio (HR) 1.51, 95% CI 1.19–2.00, P=0.001, Table 2). Other covariates associated with this outcome included no prior history of autologous transplant (HR 12.11, 95% CI 4.95–29.63, P<0.001) and resistance to (HR 2.01, 95% CI, 1.35–2.99, P<0.001) or no known prior treatment (HR 1.933, 95% CI 1.47–2.55, P<0.001, Table 2).

Figure 1.
Figure 1 - Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, please contact help@nature.com or the author

Outcomes. (a) Acute GVHD, grades II–IV. (b) Chronic GVHD. (c) Adjusted PFS. (d) Adjusted OS.

Full figure and legend (107K)


Incidences of chronic GVHD at 1 year were 54% and 44% for the TBI (95% CI 48–59%) and no-TBI groups (95% CI 39–48%), respectively (P=0.004, Figure 1b). Multivariate analysis showed higher rates of chronic GVHD with TBI (HR 1.32, 95% CI 1.10–1.59, P=0.003, Table 2) compared with no-TBI. Other covariates associated with this outcomes were partially matched URD graft source (HR 1.50, 95% CI, 1.08–2.08, P=0.015) and ATG or campath use (HR 0.60, 95% CI, 0.47–0.75, P<0.001, Table 2).

TRM and disease progression

Cumulative incidences of TRM at 1 year were 18% (95% CI, 14–22%) and 16% (95% CI, 13–19%, P=0.36) for TBI and no-TBI, respectively. Multivariate analysis of TRM showed no difference between the TBI and no-TBI cohorts (P=0.48, Table 2). Other covariates associated with TRM were: increasing patient age (age greater than or equal to60, HR 1.58 95% CI, 1.12–2.24, P=0.009) and partially matched URD source graft (HR 2.63, 95% CI, 1.79–3.87, P<0.001, Table 2).

Incidences of disease progression or relapse at 5 years were 36% (95% CI, 31–41%) and 38% (95% CI, 33–42% P=0.16) for the TBI and no-TBI cohorts, respectively. Multivariate analysis of progression/relapse showed no difference between the two cohorts (P=0.68, Table 2). Other covariates with significant association were KPS<90% (HR 1.42, 95% CI, 1.10–1.983, P=0.007) and use of ATG or campath (HR 1.55, 95% CI, 1.22–1.97, P<0.001, Table 2).

Survival

Figures 1c and d illustrated the adjusted PFS and adjusted OS, respectively. Multivariate analysis for treatment failure preventing PFS were similar for both the cohorts (HR 0.97, 95% CI, 0.81–1.51, P=0.70, Table 2). Associated covariates for treatment failure were KPS<90% (HR 1.34, 95% CI, 1.10–1.62, P=0.041) and partially matched URD source graft (HR 1.79, 95% CI 1.36–2.34, P<0.001, Table 2).

Multivariate analyses for overall mortality were similar for both the cohorts (HR 1.09, 95% CI, 0.91–1.32, P=0.35, Table 2). Additional covariates that were associated with overall mortality in the main analysis were: patient age greater than or equal to60 years at transplant (HR 1.66, 95% CI, 1.28–2.15, P<0.001), KPS<90 (HR 1.49, 95% CI, 1.21–1.83, P<0.001) and partially matched URD graft source use (HR 1.94, 95% CI, 1.46–2.59, P<0.001, Table 2).

Causes of death

Primary disease was the most common cause of death in both the cohorts. TBI group had more deaths due primarily to GVHD (17% vs 8%) and organ failure (15% vs 12%), and the no-TBI group had more deaths from infection (18% vs 11%) compared with the TBI group (P<0.001). Reviewing the contributing causes of death, a similar trend was found. TBI cohort had 16% and the no-TBI cohort had 9% deaths contributed by GVHD (P=0.007). However, deaths related to infection were similar between the two cohorts (16% in the TBI and 15% in the no-TBI cohorts, P=0.92).

Chimerism analysis

Chimerism analysis with unsorted specimens was available in 62 and 88 patients; and T-cell chimerism was available in 34 and 70 patients in the TBI and no-TBI groups, respectively. Among the unsorted chimerism, achievement of full donor chimerism by day 100 was observed in 82% and 64% in the TBI and no-TBI cohorts, respectively (P=0.006). Loss of donor chimerism after initially achieving full donor chimerism was not observed in any cohort. In all, 10% vs 31% of the TBI and no-TBI cohorts, respectively, achieved only mixed chimerism. Median donor chimerism by day 100 was 100% vs 95% for the TBI and no-TBI groups, respectively (Figure 2a). The median donor chimerism among patients with mixed unsorted chimerism from both the treatment groups at the last period analyzed (days 76–100) was 79% (N=26, range 32–89%) for all patients. Among patients with lymphocyte chimerism, achievement of full donor chimerism by day 100 was observed in 53% and 59% in the TBI and no-TBI groups respectively (P=0.027). Loss of T-cell donor chimerism was not found in any cohort. In all, 26% vs 37% of TBI and no-TBI, respectively, maintained mixed T-cell chimerism during the period. Median donor T-cell chimerism by day 100 was 94.5% and 95% for the TBI and no-TBI groups (P=0.84; Figure 2b). The median donor chimerism among patients with mixed T-cell chimerism from both the treatment groups at the last period analyzed (day 76–100) was 70% (N=37, range 19–89%) for all the patients.

Figure 2.
Figure 2 - Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, please contact help@nature.com or the author

Percentage of donor chimerism for (a) unsorted cells and (b) sorted lymphocytes after HCT. Individual percentage of donor chimerisms are indicated with and × symbols, and lines indicate the changes of medians by each group.

Full figure and legend (68K)

Subset analysis

Five groups were analyzed: flu/ TBI-CNI-MMF (TBI-MMF cohort, n=230), flu/cy/rituximab-CNI-MTX (FCR cohort, n=97), FCR-CNI-MTX-in vivo T-cell depletion, including campath and rabbit or horse ATG (FCR-in vivo TCD cohort, n=59), flu/cy-CNI-MTX (FC cohort, n=82), and others (n=231).

When comparing the above groups, FCR contained more cases of follicular lymphoma (61% vs 21–31%, P=0.031) in relapsed status (37% vs 25–29%, P<0.001). TBI-MMF and FCR-in vivo TCD groups included more URD recipients (67% and 98%, respectively, vs 25–28%, P<0.001). TBI-MMF and FC groups included fewer patients with KPSgreater than or equal to90% (31% and 26%, respectively, vs 7–11%, P<0.001).

The cumulative incidences of acute GVHD, grades II–IV at 100 days were 35% of TBI-MMF (95% CI 29–42%), 20% of FCR (95% CI 12–28% for both), 12% of FC (95% CI 5–22%), 11% of FCR-in vivo TCD (95% CI 5–19%) and 29% of others (95% CI 23–35, P<0.001, Figure 3a). Chronic GVHD at 1 year in the TBI-MMF cohort was 55% and in other cohorts it was 41–48% (P=0.11, Figures 3b and 4a). Multivariate analysis demonstrated that TBI-MMF was associated with higher incidence of chronic GVHD (Figure 4b).

Figure 3.
Figure 3 - Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, please contact help@nature.com or the author

Outcomes of regimen–GVHD prophylaxis combinations. (a) Acute GVHD, grades II–IV. (b) Chronic GVHD. (c) Adjusted PFS. (d) Adjusted OS.

Full figure and legend (154K)

Figure 4.
Figure 4 - Unfortunately we are unable to provide accessible alternative text for this. If you require assistance to access this image, please contact help@nature.com or the author

Multivariate analysis of regimen–GVHD prophylaxis combinations. Hazard ratios of incidence of (a) acute GVHD, grades II–IV by day 100 and (b) chronic GVHD. Lines indicating the TBI-MMF group were the referents.

Full figure and legend (69K)

TRM (P=0.053), progression/relapse (P=0.58), PFS (P=0.11) and OS (P=0.06) showed no statistical difference from multivariate analyses among the five groups (Figure 3c and d).

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Discussion

NMA HCTs with or without TBI have been used to treat patients with LD. This study demonstrated that use of a general immunoablative regimen with TBI results in no major differences in post-HCT outcomes compared with disease-specific regimens using chemotherapy. Additionally, TBI appears to cause less ablation of hematopoiesis as a greater proportion of patients do not become neutropenic compared with chemotherapy only regimens. This translated into faster time to full donor chimerism but no difference in proportion of donor chimerism by day 100. One important difference in outcomes noted in this study was a higher rate of GVHD with TBI regimens, which was maintained after adjusting for differences in the donor type and graft source between the two cohorts. Subset analysis suggests that the choice of GVHD prophylaxis can modulate this complication post HCT as MMF-based regimens are associated with higher GVHD rates compared with other combinations.

Other single center experiences with NMA regimens in specific LD showed that OS and PFS for CLL (2-year OS 60% and disease-free survival 52%) and follicular lymphoma (2-year disease-free survival of 64% in high grade and 83% in low grade) were comparable with this study.8, 10, 19 Also, median survival for patients with advanced CLL or follicular lymphoma utilizing low-dose TBI (OS 64–86% at 4 years) from previous studies were comparable, when contrasted with other conditioning regimens without TBI (OS 46–84% at 4–5 years).8, 10 Three-year rates of relapse were comparable with other reported studies for follicular lymphomas of 20–45% on average, although some studies had relapse rates less than or equal to10% at 2–3 years.9, 11, 20

In this study, increased acute GVHD incidence in TBI group could also be the effect of donor chimerism, as suggested by a faster achievement of full donor chimerism,7, 20, 21, 22 despite similar day-100 donor chimerism between the groups making this argument less plausible. Alternatively, the cohorts differed in GVHD prophylaxis regimens, which could be responsible for the difference of acute GVHD incidence. For chronic GVHD, both use of ATG or campath and HLA-matching were associated with lower rates of chronic GVHD as previously observed.23, 24 Furthermore, the use of rituximab was more common in the no-TBI cohort, which could mitigate the incidence of GVHD. Exposure to rituximab was tested in the statistical models, and it was not significantly associated with any of the outcomes tested.

Moreover, a systematic review of 11 studies showed increased incidence of grades III–IV acute GVHD for patients who received MMF when compared with those who received MTX for GVHD prophylaxis (relative risk 1.61, 95% CI 1.18–2.30).23 Chen et al. reported that tacrolimus (TAC)/MMF resulted in higher grades III–IV acute GVHD (49%) when compared with TAC/MTX (19%) and TAC/micro-MTX/MMF (23%) following myeloablative conditioning (P<0.015).25, 26 Also, this is comparable with other single-center NMA and myeloablative studies, which revealed that MMF-based GVHD prophylaxis increased incidences of acute GVHD (11.6–54.5%) when compared with other regimen.25, 26, 27

In studying TBI-based NMA conditioning regimen, Kornbilt et al.28 explained that addition of Flu-TBI (2Gy) reduced graft rejection by hastening donor chimerism. Although both groups with and without Flu demonstrated near-complete donor granulocyte chimerism, median number of days of absolute granulocyte counts >500cells/μL was higher in Flu/TBI.

The current study is a retrospective analysis from a large number of transplant centers. The major pitfall is based on the decision to select a particular regimen, which was based on clinical evaluation by the treating physician. The selection of the study population separated by conditioning regimens demonstrated differences between groups. Several approaches were taken to minimize the heterogeneity of the population, including restricting the age of patients to >40 years, selection of common indications and excluding practices that are not commonly performed, such as T-cell depletion, cord blood and use of mismatched URD. Furthermore, the regression analysis was able to adjust for the remainder of differences between the cohorts.

Nevertheless, this study was a large comparison of NMA regimens among HCT recipients with LD. This study demonstrated that TBI-based and non-TBI-based NMA regimens with Flu achieved similar disease control and survival outcomes. TBI regimens lead to faster full donor chimerism. Finally, the results of this study raises the hypotheses that differences on GVHD rates observed were possibly related to the specific GVHD prophylaxis most commonly used with TBI NMA regimens.

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Conflict of interest

The authors declare no conflict of interest.

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References

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Acknowledgements

We thank Professor John Klein for the valuable input on the design of this study who had contributed significantly for the development of this study. We would like to dedicate this study to Dr Klein’s memory. The CIBMTR is supported by Public Health Service Grant/Cooperative Agreement U24-CA076518 from the National Cancer Institute (NCI), the NHLBI and the National Institute of Allergy and Infectious Diseases (NIAID); a Grant/Cooperative Agreement 5U10HL069294 from NHLBI and NCI; a contract HHSH250201200016C with Health Resources and Services Administration (HRSA/DHHS); two Grants N00014-12-1-0142 and N00014-13-1-0039 from the Office of Naval Research; and grants from *Actinium Pharmaceuticals; Allos Therapeutics, Inc.; *Amgen, Inc.; Anonymous donation to the Medical College of Wisconsin; Ariad; Be the Match Foundation; *Blue Cross and Blue Shield Association; *Celgene Corporation; Chimerix, Inc.; Fred Hutchinson Cancer Research Center; Fresenius-Biotech North America, Inc.; *Gamida Cell Teva Joint Venture Ltd; Genentech, Inc.;*Gentium SpA; Genzyme Corporation; GlaxoSmithKline; Health Research, Inc. Roswell Park Cancer Institute; HistoGenetics, Inc.; Incyte Corporation; Jeff Gordon Children’s Foundation; Kiadis Pharma; The Leukemia and Lymphoma Society; Medac GmbH; The Medical College of Wisconsin; Merck and Co, Inc.; Millennium: The Takeda Oncology Co.; *Milliman USA, Inc.; *Miltenyi Biotec, Inc.; National Marrow Donor Program; Onyx Pharmaceuticals; Optum Healthcare Solutions, Inc.; Osiris Therapeutics, Inc.; Otsuka America Pharmaceutical, Inc.; Perkin Elmer, Inc.; *Remedy Informatics; *Sanofi US; Seattle Genetics; Sigma-Tau Pharmaceuticals; Soligenix, Inc.; St Baldrick’s Foundation; StemCyte, A Global Cord Blood Therapeutics Co.; Stemsoft Software, Inc.; Swedish Orphan Biovitrum; *Tarix Pharmaceuticals; *TerumoBCT; *Teva Neuroscience, Inc.; *THERAKOS, Inc.; University of Minnesota; University of Utah; and *Wellpoint, Inc. The views expressed in this article do not reflect the official policy or position of the National Institute of Health, the Department of the Navy, the Department of Defense, Health Resources and Services Administration (HRSA) or any other agency of the US Government. *Corporate members.