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Follicular lymphoma (FL) is the most common indolent B-cell non-Hodgkin lymphoma (NHL), accounting for nearly one-third of all NHL. The therapeutic landscape for patients with FL has significantly expanded over the past decade, but the disease continues to be considered incurable. Hematopoietic cell transplantation (HCT) is potentially curative in some cases. Recently, the emergence of chimeric antigen receptor T-cell therapy (CAR-T) for patients with relapsed/refractory (R/R) FL has yielded impressive response rates and long-term remissions, but definitive statement on the curative potential of CAR-T is currently not possible due to limited patient numbers and relatively short follow up. A consensus on the contemporary role, optimal timing, and sequencing of HCT (autologous or allogeneic) and cellular therapies in FL is needed. As a result, the American Society of Transplantation and Cellular Therapy (ASTCT) Committee on Practice Guidelines endorsed this effort to formulate consensus recommendations to address this unmet need. The RAND-modified Delphi method was used to generate 15 consensus statements/recommendations. These clinical practice recommendations will help guide clinicians managing patients with FL. Of note, the use of bispecific antibodies in R/R FL was not in the scope of this project., (Copyright © 2024 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Abstract: Chimeric antigen receptor T-cell therapy (CAR T) has revolutionized the treatment of hematological cancers. Its production requires a complex logistical process, and the time from leukapheresis to patient infusion (known as the vein-to-vein time [V2VT]) can be long during which a patients clinical condition may deteriorate. This study was designed to estimate the benefits of reduced V2VT for third-line or later (3L+) relapsed/refractory large B-cell lymphoma (R/R LBCL) patients treated with CAR T. A mathematical model was developed to estimate the lifetime outcomes of a hypothetical cohort of patients who had either a long or short V2VT. Life-years (LYs), quality-adjusted LYs (QALYs), and costs were estimated. Scenario analyses were performed to assess the robustness of results to key assumptions. The results of the model show that reducing V2VT from 54 days (tisa-cel median V2VT; JULIET) to 24 days (axi-cel median V2VT; ZUMA-1) led to a 3.2-year gain in life expectancy (4.2 vs 7.7 LYs), and 2.4 additional QALYs (3.2 vs 5.6) per patient. Furthermore, a shorter V2VT was shown to be cost-effective under conventional willingness-to-pay thresholds in the United States. Results are driven by a higher infusion rate and a better efficacy of CAR T for those infused. Scenario analyses using a smaller difference in V2VT (24 vs 36 days) produced consistent results. Our study is the first to quantify lifetime V2VT-related outcomes for 3L+ R/R LBCL patients treated with CAR T utilizing currently available evidence. Shorter V2VTs led to improved outcomes, demonstrating the importance of timely infusion achievable by faster manufacturing times and optimization of hospital delivery., (© 2024 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.)

Purpose: BMT CTN 1102 was a phase III trial comparing reduced-intensity allogeneic hematopoietic cell transplantation (RIC alloHCT) to standard of care for persons with intermediate- or high-risk myelodysplastic syndrome (MDS). We report results of a cost-effectiveness analysis conducted alongside the clinical trial., Methods: Three hundred eighty-four patients received HCT (n = 260) or standard of care (n = 124) according to availability of a human leukocyte antigen-matched donor. Cost-effectiveness was calculated from US commercial and Medicare perspectives over a 20-year time horizon. Health care utilization and costs were estimated using propensity score-matched cohorts of HCT recipients in the OptumLabs Data Warehouse (age 50-64 years) and Medicare (age 65 years and older). EuroQol 5 Dimension (EQ-5D) surveys of trial participants were used to derive health state utilities., Results: Extrapolated 20-year overall survival for those age 50-64 years was 29% for HCT (n = 105) versus 13% for usual care (n = 44) and 31% for HCT (n = 155) versus 12% for non-HCT (n = 80) for those age 65 years and older. HCT was more effective (+2.36 quality-adjusted life-years [QALYs] for age 50-64 years and +2.92 QALYs for age 65 years and older) and more costly (+$452,242 in US dollars (USD) for age 50-64 years and +$233,214 USD for age 65 years and older) than usual care, with incremental cost-effectiveness ratios of $191,487 (USD)/QALY and $79,834 (USD)/QALY, respectively. For persons age 50-64 years, there was a 29% chance that HCT was cost-effective using a willingness-to-pay (WTP) threshold of $150K (USD)/QALY and 51% at a $200K (USD)/QALY. For persons age 65 years and older, the probability was 100% at a WTP >$150K (USD)/QALY., Conclusion: Among patients age 65 years and older with high-risk MDS, RIC HCT is a high-value strategy. For those age 50-64 years, HCT is a lower-value strategy but has similar cost-effectiveness to other therapies commonly used in oncology.

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of many patients with aggressive relapsed or refractory large B-cell lymphoma (LBCL). Treatment can be complicated by clinically evident cytokine release syndrome (CRS), which is characterized by the development of fever, hypoxia, and hypotension, and can be life-threatening. Most patients treated with CAR-T cells develop CRS, which is thought to represent an immune phenomenon. It was previously unknown whether patients who did not develop CRS had reduced CAR-T cell activity and were therefore likely to have worse outcomes. We conducted a multicenter retrospective analysis of 352 adult patients treated at 8 academic medical centers in the United States who received axicabtagene ciloleucel or tisagenlecleucel for the treatment of LBCL. The outcomes of interest included progression-free survival, overall survival, complete response rate, and overall response rate. Of the included patients, 262 (74.4%) developed CRS. There was no significant difference in progression-free survival (P = .99) or overall survival (P = .16) between patients who developed CRS and those who did not develop CRS. Peak ferritin levels >5000 ng/mL during treatment and lactate dehydrogenase levels greater than the institutional upper limit of normal before lymphodepleting chemotherapy were associated with significantly worse progression-free and overall survival in the multivariate analysis. There was no significant difference in the complete response or overall response rates between patients who did and did not develop CRS. In this retrospective analysis, we report that patients who develop CRS have clinical outcomes similar to those of patients without CRS treated with commercial anti-CD19 CAR-T cells., (© 2023 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.)

Axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisa-cel) are CD19-directed chimeric antigen receptor (CAR) T cell therapies approved for the treatment of relapsed/refractory aggressive B cell lymphomas. We present a multicenter retrospective study among centers that prescribe either commercial product to evaluate usage patterns, safety and efficacy outcomes, and resource utilization. Data collection included all patients from 8 US centers who underwent apheresis between May 1, 2018, and July 31, 2019. Patient selection, toxicity management, and disease assessment followed institutional practices. Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were graded according to American Society for Transplantation and Cellular Therapy consensus criteria, and tumor responses were assessed according to the Lugano 2014 classification scheme. A total of 260 patients underwent apheresis, including 168 (65%) for axi-cel and 92 (35%) for tisa-cel. Among the infused patients, the median age was 59 years for axi-cel recipients and 67 years for tisa-cel recipients (P < .001). The median time from apheresis to infusion was 28 days for axi-cel recipients and 45 days for tisa-cel recipients (P < .001). Sixty-one percent of the axi-cel recipients and 43% of the tisa-cel recipients would have been ineligible for the ZUMA-1 and JULIET trials, respectively. Grade ≥3 CRS occurred in 9% of axi-cel recipients and in 1% of tisa-cel recipients (P = .017), and grade ≥3 ICANS was seen in 38% of axi-cel recipients and 1% of tisa-cel recipients (P < .001). Inpatient cell therapy infusion was common (92% in axi-cel recipients, 37% in tisa-cel recipients). The day 90 overall response rate was 52% in the axi-cel group and 41% in the tisa-cel group (P = .113), with complete response in 44% and 35%, respectively (P = .319). Twelve-month progression-free survival (42% versus 32%; P = .206) and overall survival (62% versus 59%; P = .909) rates were comparable in the axi-cel and tisa-cel groups. Baseline characteristics differed between the 2 groups, although response rates and survival outcomes were comparable, albeit lower than those in the pivotal trials. Safety and resource utilization appear to be key differentiators between axi-cel and tisa-cel., (Copyright © 2022 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

This study compared the real-world healthcare resource utilization (HRU), costs, adverse events (AEs), and AE treatments associated with the chimeric antigen receptor T-cell (CAR-T) therapies, tisagenlecleucel (tisa-cel) and axicabtagene ciloleucel (axi-cel), for relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL). Adults with DLBCL who received tisa-cel or axi-cel were identified in the Premier Healthcare Database (2017-2020). Non-CAR-T costs, HRU, and AE rates during the infusion and follow-up periods were compared between the tisa-cel and axi-cel cohorts. Of 119 patients, 33 received tisa-cel (86% as inpatient infusion) and 86 received axi-cel (100% inpatient). Tisa-cel was associated with significantly shorter mean inpatient length of stay than axi-cel during infusion (11.3 vs. 18.3 days) and follow-up ([monthly] 3.9 vs. 6.9 days). Non-CAR-T costs were significantly lower for tisa-cel compared with axi-cel during infusion ($27594.8 vs. $51378.3) and follow-up ([monthly] $28777.3 vs. $46575.7; both p < .05). Rates of AEs and AE treatments were similar.

The effect of chronic graft-versus-host disease (cGVHD) on the risk of nonrelapse mortality (NRM) and relapse has not been specifically studied in older adults, who are increasingly undergoing allogeneic hematopoietic cell transplantation (alloHCT) and surviving long-term to develop cGVHD. In this Center for International Blood and Marrow Transplant Research (CIBMTR) analysis, we tested our hypothesis that the risk of NRM was higher with the development of cGVHD, particularly among older adults (age ≥60 years). We included 4429 adults age ≥40 years who underwent a first HLA-matched peripheral blood stem cell alloHCT for acute myelogenous leukemia or myelodysplastic syndrome between 2008 and 2017. We compared outcomes of 4 groups-older adults (≥60 years) and younger adults (40 to 59 years) with cGVHD and older and younger adults without cGVHD-to determine the effect of older age and cGVHD on various outcomes. We used Cox proportional hazard models to determine the risk of NRM, relapse, and overall survival (OS). We treated cGVHD as a time-dependent covariate. The severity of cGVHD was based on the CIBMTR clinical definitions. cGVHD was significantly associated with a higher risk of NRM and lower risk of relapse regardless of age. The risk of NRM was higher for older adults versus younger adults. Adults who developed cGVHD as a group had longer OS compared with age-matched cohorts without cGVHD. Older adults had worse OS regardless of cGVHD. Among adults with cGVHD, clinically moderate or severe cGVHD was associated with a significantly higher risk of NRM and lower risk of relapse; severe cGVHD was associated with shorter OS, whereas mild to moderate cGVHD was associated with longer OS. Among both younger and older adults, the development of cGVHD was associated with a higher risk of NRM, lower risk of relapse, and longer OS. Older adults had a higher risk of NRM, but the increased risk of NRM associated with cGVHD did not differ based on age. The development of mild to moderate cGVHD offered the most favorable balance between minimizing NRM and decreasing the risk of relapse. The relapse risk was lowest for adults with severe cGVHD, but high NRM resulted in shorter OS. Developing strategies to avoid clinically severe cGVHD is critically important. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc., (Copyright © 2021 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

Background and Objective: The objective of this study was to estimate the lifetime costs of patients receiving treatment for follicular lymphoma (FL) in the United States., Methods: A Markov model was programmed in hēRo3 with a 6-month cycle length, 35-year time horizon (lifetime projection), and health states for line of treatment, response, receipt of maintenance therapy among responders, transformation to diffuse large B-cell lymphoma (DLBCL), development of second primary malignancy (SPM), and death. The model was used to estimate the expected lifetime costs of FL (in 2019 USD), including costs of drug acquisition and administration, transplant procedures, radiotherapy, adverse events, follow-up, DLBCL, SPM, end-of-life care, and indirect costs. Model inputs were based on published sources., Results: In the US, patients with FL receiving treatment have a life expectancy of approximately 14.5 years from initiation of treatment and expected lifetime direct and indirect costs of US$515,884. Costs of drugs for induction therapy represent the largest expenditure (US$233,174), followed by maintenance therapy costs (US$88,971) and terminal care costs (US$57,065). Despite the relatively advanced age of these patients, indirect costs (due to patient morbidity and mortality and caregiver lost work time) represent a substantial share of total costs (US$40,280). Treated FL patients spend approximately 6.9 years in the health states associated with first-line therapy. Approximately 66 and 46% continue to second- and third-line therapies, respectively. The mean (95% credible interval) of expected lifetime costs based on the probabilistic sensitivity analyses was US$559,202 (421,997-762,553)., Conclusions: In the US, the expected lifetime costs of care for FL patients who receive treatment is high. The results highlight the potential economic benefits that might be achieved by treatments for FL that prevent or delay disease progression., (© 2021. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

The SARS-CoV-2 coronavirus (COVID-19) pandemic has significantly impacted the delivery of cellular therapeutics, including chimeric antigen receptor (CAR) T cells. This impact has extended beyond patient care to include logistics, administration, and distribution of increasingly limited health care resources. Based on the collective experience of the CAR T-cell Consortium investigators, we review and address several questions and concerns regarding cellular therapy administration in the setting of COVID-19 and make general recommendations to address these issues. Specifically, we address (1) necessary resources for safe administration of cell therapies; (2) determinants of cell therapy utilization; (3) selection among patients with B cell non-Hodgkin lymphomas and B cell acute lymphoblastic leukemia; (4) supportive measures during cell therapy administration; (5) use and prioritization of tocilizumab; and (6) collaborative care with referring physicians. These recommendations were carefully formulated with the understanding that resource allocation is of the utmost importance, and that the decision to proceed with CAR T cell therapy will require extensive discussion of potential risks and benefits. Although these recommendations are fluid, at this time it is our opinion that the COVID-19 pandemic should not serve as reason to defer CAR T cell therapy for patients truly in need of a potentially curative therapy., Competing Interests: Conflict of interest statement V.B. has received research funding from Novartis, Celgene, Incyte, Gamida Cell, and GT Biopharma and serves on advisory boards for Kite Pharma/Gilead and Seattle Genetics. M.R.B. serves as a consultant and/or advisor for Celgene, Kite Pharma/Gilead, CRISPR Therapeutics, and Novartis and on speakers bureaus for Kite Pharma/Gilead, BMS, and Celgene, and has other financial interests/relationships with Novartis as a part of steering committees. P.D. serves on the advisory board for Kite Pharma/Gilead. B.D. serves as a consultant and/or advisor for Celgene and has received institutional research support from Angiocrine Bioscience, Celyad, and Poseida Therapeutics. S.A.G. has served as a consultant for CBMG, Novartis, Roche, GSK, Cure Genetics, Humanigen, and Jazz Pharmaceuticals; has received research funding from Novartis, Kite Pharma/Gilead, and Servier; and serves on study steering committees or scientific advisory boards for Jazz Pharmaceuticals and Adaptimmune. B.H.-L. and M.J. have no conflicts to disclose. R.T.M. has received honoraria/consultant fees from BMS/JUNO, CRISPR Therapeutics, Kite Pharma/Gilead, Incyte, Intellia Therapeutics, Kadmon, Omeros, and PACT Pharma; serves on a scientific board for Artiva Biotherapeutics; has served on data and safety monitoring boards for Novartis and Athersys; served as chair of the scientific steering committee for the phase II tisagenlecleucel study sponsored by Novartis; and has received research support from Novartis. He also holds patents from Athersys. J.P.M. has received research/grant support from Novartis, Fresenius Biotech, Astellas, Bellicum Pharmaceuticals, Gamida Cell, and Pluristem; has served on advisory boards/speakers bureaus for and received travel accommodations and expenses and research funding from Kite Pharma/Gilead and BMS/JUNO; and has received honoraria, travel expenses along with grant/research funding from AlloVir. L.J.N. has received honoraria from Bayer, Celgene, Gamida Cell, Genentech, Kite Pharma/Gilead, Novartis, MEI, and TG Therapeutics along with research support from Celgene, Genentech, Karus Therapeutics, Merck, Novartis, and TG Therapeutics. O.O.O. has served on scientific advisory boards for Pfizer, Spectrum, Bayer, and Kite Pharma/Gilead; has received honoraria from Pfizer; and has received research support from Novartis. M.-A.P. has received honoraria from AbbVie, Bellicum, BMS, Incyte, Merck, Novartis, Nektar Therapeutics, Omeros, and Takeda; serves on data safety and monitoring boards for Servier and Medigene and on scientific advisory boards of MolMed and NexImmune; and has received research support for clinical trials from Incyte, Kite Pharma/Gilead, Miltenyi Biotec, and Novartis. D.L.P. reports spousal employment along with stock and other ownership interests in Genentech and Roche; has served in a consulting/advisory capacity for Novartis, Kite Pharma/Gilead, Incyte, Gerson Lehrman Group, Glenmark, and Janssen; has received travel expenses from Kite Pharma and Novartis; has received research funding from Novartis; is a listed as an inventor on a patent for CTL019; and serves on the Board of Directors of the National Marrow Donor Program and on the Board Examination Writing Committee of the American Board of Internal Medicine. P.A.R. has served on speakers bureaus for Kite Pharma/Gilead and Bayer and on advisory boards for Verastem Oncology, Novartis, Celgene/BMS, and Bayer; has received honoraria from Novartis; and has received research support from Celgene/BMS, Kite Pharma, and Novartis., (Copyright © 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.)

We retrospectively analyzed treatment patterns and healthcare costs among patients diagnosed with diffuse large B-cell lymphoma (DLBCL) during each line of therapy (LOT) using data from the IBM ® MarketScan ® Commercial and Medicare Supplemental Databases from January 2011 to May 2017. Patients were included if they had a diagnosis of DLBCL, ≥12 months of disease-free continuous enrollment prediagnosis, and ≥1 month of postdiagnosis follow-up. Of 2066 eligible patients receiving first-line treatment, 17% ( n  = 340) received second-line treatment; of these, 23% ( n  = 77) received third-line treatment. Mean healthcare expenditures (treatment duration) for first, second, and third LOTs were $111,314 (124.5 days), $88,472 (80.8 days), and $103,365 (70.9 days), respectively. When adjusted to 30-day period costs, first, second, and third LOT healthcare expenditures increased to $26,825, $32,857, and $43,854, respectively. Patients with newly diagnosed and relapsed/refractory DLBCL incur a significant cost burden (for payers), and such costs increase as patients proceed through subsequent LOTs.

Cellular therapies and other regenerative medicines are emerging as potentially transformative additions to modern medicine, but likely at a staggering financial cost. Public health care systems' budgets are already strained by growing and aging populations, and many private insurer's budgets are equally stretched. The current systems that most payers employ to manage their cash flow are not structured to absorb a sudden onslaught of very expensive prescriptions for a large portion of their covered population. Despite this, developers of new regenerative medicines tend to focus on the demands of regulators, not payers, in order to be compliant throughout the clinical trials phases, and to develop a product that ultimately will be approvable. It is not advisable to assume that an approved product will automatically become a reimbursed product, as examples from current practice in hematopoietic stem cell transplantation in the U.S. demonstrate; similarly, in Europe numerous Advanced-therapy Medicinal Products achieved market authorization but failed to secure reimbursement (e.g., Glybera, Provenge, ChondroCelect, MACI). There are however strategies and approaches that developers can employ throughout clinical development, in order to generate clinical and health economic data which will be necessary to demonstrate the value proposition of the new product and help ensure market access for patients; furthermore, performance based managed entry agreements coupled with post-launch evidence generation can help overcome challenges around product uncertainty at launch and reduce market access delays. Stem Cells Translational Medicine 2017;6:1723-1729., (© 2017 The Authors Stem Cells Translational Medicine published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.)

Before US regulatory approval, an expanded access program provided plerixafor to patients with non-Hodgkin's lymphoma (NHL), Hodgkin's lymphoma (HD) or multiple myeloma (MM) who had not previously failed mobilization and were otherwise candidates for auto-SCT. Patients received granulocyte-CSF (G-CSF) 10 mcg/kg daily and plerixafor 0.24 mg/kg starting on day 4 with apheresis on day 5; all repeated daily until collection was complete. Overall, 104 patients received 1 dose of plerixafor. The addition of plerixafor to G-CSF resulted in a median threefold increase in peripheral blood CD34+ cell count between days 4 and 5. Among 43 NHL patients, 74% met the target of 5 × 10(6) CD34+ cells/kg (median, 1 day apheresis, range 1-5 days); among 7 HD patients, 57% met the target of 5 × 10(6) CD34+ cells/kg (median, 2 days apheresis, range 1-3); and among 54 MM patients, 89% met the target of 6 × 10(6) CD34+ cells/kg (median, 1 day apheresis, range 1-4). Overall, 93% of patients had 2 × 10(6) CD34+ cells/kg collected within 1-3 days. Plerixafor-related toxicities were minimal. Engraftment kinetics, graft durability and transplant outcomes demonstrated no unexpected outcomes. Efficacy and safety results were similar to results in phase II and III clinical trials.

Hematopoietic cell transplantation (HCT) is the only known curative therapy for many patients with life-threatening hematologic and oncologic diseases. It is estimated that the National Marrow Donor Program(®) (NMDP) will facilitate 10,000 transplants by 2015, double the current number. To better understand the existing personnel and center infrastructure for HCT in the country and to address system capacity challenges to the future growth of HCT, the NMDP convened a diverse group of stakeholders and thought leaders representing HCT physicians, physician assistants, nurse practitioners, nurses, pharmacists, other healthcare providers, HCT program directors, hospital administrators, payors, and professional organizations. Working groups were formed to identify: capacity issues because of shortages in human resources, structural constraints, and patient access barriers including diversity and healthcare disparity challenges; recommendations to address challenges; and stakeholders to engage. This report details the deliberations and recommendations of a national symposium, "Hematopoietic Cell Transplantation in 2020: A Health Care Resource and Infrastructure Assessment," held in September 2010., (Copyright © 2012 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

As costly stem cell treatments progress from experimental concepts toward licensed products and routine procedures, governmental and private payers grapple with shrinking budgets to cover more lives. We describe efforts underway in the US to create mechanisms for reimbursement of cell therapies and discuss other reimbursement-related issues for the stem cell community., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Studies suggest that patients who live in rural areas may have worse clinical outcomes compared with patients living in urban areas. We studied whether place of residence (rural versus urban) is associated with clinical outcomes of patients with leukemia or myelodysplastic syndrome (MDS) who received an unrelated donor hematopoietic cell transplantation (HCT). Patients' residential ZIP code at the time of transplant was used to determine rural or urban designation based on the Rural Urban Commuting Codes. The study included 6140 patients reported to the Center for International Blood and Marrow Transplant Research (CIBMTR) from 121 U.S. HCT centers: 1179 (19%) came from rural areas, whereas 4961 (81%) came from urban areas. Rural and urban patients were similar in patient-, disease-, and transplant-related characteristics aside from household income and distance traveled to the HCT center. After adjusting for income and other significant patient, disease, and transplant-related variables, the risk of overall mortality between patients residing in rural and urban areas were not statistically significant (relative risk 1.01, 95% confidence intervals 0.93-1.10, P = .74). Similar outcomes were noted for treatment-related mortality (TRM), disease-free survival (DFS), and relapse. Patient's income, derived from the U.S. Census and based on their residential ZIP code, was independently associated with outcomes. In summary, our study showed no differences in the clinical outcomes of patients from rural or urban areas after unrelated donor HCT., (Copyright (c) 2010 Elsevier Inc. All rights reserved.)

Purpose: Acute graft-versus-host disease (GVHD) causes substantial morbidity and mortality after human leukocyte antigen (HLA)-identical sibling transplants. No large registry studies of acute GVHD risk factors have been reported in two decades. Risk factors may have changed in this interval as transplant-related techniques have evolved., Patients and Methods: Acute GVHD risk factors were analyzed in 1,960 adults after HLA-identical sibling myeloablative transplant for acute myeloid leukemia (AML), acute lymphocytic leukemia (ALL), or chronic myeloid leukemia (CML) reported by 226 centers worldwide to the Center for International Blood and Marrow Transplant Research from 1995 to 2002. Outcome was measured as time from transplant to onset of grade 2 to 4 acute GVHD, with death without acute GVHD as a competing risk., Results: Cumulative incidence of grade 2 to 4 acute GVHD was 35% (95% CI, 33% to 37%). In multivariable analyses, factors significantly associated with grade 2 to 4 acute GVHD were cyclophosphamide + total-body irradiation versus busulfan + cyclophosphamide (relative risk [RR] = 1.4; P < .0001), blood cell versus bone marrow grafts in patients age 18 to 39 years (RR = 1.43; P = .0023), recipient age 40 and older versus age 18 to 39 years receiving bone marrow grafts (RR = 1.44; P = .0005), CML versus AML/ALL (RR = 1.35; P = .0003), white/Black versus Asian/Hispanic race (RR = 1.54; P = .0003), Karnofsky performance score less than 90 versus 90 to 100 (RR = 1.27; P = .014), and recipient/donor cytomegalovirus-seronegative versus either positive (RR = 1.20; P = .04). Stratification by disease showed the same significant predictors of grade 2 to 4 acute GVHD for CML; however, KPS and cytomegalovirus serostatus were not significant predictors for AML/ALL., Conclusion: This analysis confirmed several previously reported risk factors for grade 2 to 4 acute GVHD. However, several new factors were identified whereas others are no longer significant. These new data may facilitate individualized risk estimates and raise several interesting biologic questions.