Unrelated Donor Hematopoietic Cell Transplantation Research Articles

Haploidentical versus Matched Unrelated versus Matched Sibling Donor Hematopoietic Cell Transplantation with Post-Transplantation Cyclophosphamide

With the use of post-transplantation cyclophosphamide (PTCy), the outcomes of mismatched related donor hematopoietic cell transplantation (HCT) are now approaching those of matched donor HCT. Here we compared haploidentical donor HCT versus HLA-matched unrelated donor (MUD) HCT and HLA-identical sibling donor (MSD) HCT in a cohort in which all patients received PTCy for graft-versus-host disease (GVHD) prophylaxis. We included 661 patients (275 haploidentical, 246 MUD, and 140 MSD HCT). The most common diagnoses were acute myelogenous leukemia and myelodysplastic syndrome. In multivariate analysis, the haploidentical group was found to have significantly higher nonrelapse mortality (NRM) (hazard ratio [HR], 3.2; 95% confidence interval [CI], 2 to 4.9; P < .001) and inferior progression-free survival (HR, 1.8; 95% CI, 1.4 to 2.4; P < .001) and overall survival (OS; HR, 2.2; 95% CI, 1.6 to 3; P < .001) compared with the MUD group. Relapse was the most common cause of death in all groups. Among causes of NRM, the haploidentical group had more infection-related deaths and fewer GVHD-related deaths than the other groups. The haploidentical group also had a higher risk of viral and fungal infections, grade ≥3 hemorrhagic cystitis, and cardiovascular toxicities and slower reconstitution of CD4, CD8, and regulatory T cells but faster reconstitution of natural killer cells. In an exploratory analysis, older patients with older donors (>50 years for both) appeared to have particularly high NRM and lower OS in the haploidentical group compared with the other groups. Our data suggest that even with the use of PTCy, the outcomes of haploidentical HCT are inferior to those of HLA-matched donor HCT.

406 - Post-Transplant Cyclophosphamide (PTCy) Is Associated with Superior Gvhd-Free, Relapse-Free Survival (GRFS) in HLA-Mismatched Unrelated Donor (MMUD) Hematopoietic Cell Transplantation

406 - Post-Transplant Cyclophosphamide (PTCy) Is Associated with Superior Gvhd-Free, Relapse-Free Survival (GRFS) in HLA-Mismatched Unrelated Donor (MMUD) Hematopoietic Cell Transplantation

Cytokine Release Syndrome during Antithymocyte Globulin/Anti-T Lymphocyte Globulin Serotherapy for Graft-versus-Host Disease Prophylaxis before Allogeneic Hematopoietic Stem Cell Transplantation: Incidence and Early Clinical Impact According to American Society of Transplantation and Cellular Therapy Grading Criteria

Antithymocyte globulin (ATG)/anti-T lymphocyte globulin (ATLG) aids graft-versus-host disease (GVHD) prophylaxis in HLA-matched related and unrelated donor hematopoietic stem cell transplantation (HSCT). Its use is frequently accompanied by systemic infusion reactions attributable to cytokine release syndrome (CRS). However, detailed data on ATG/ATLG-induced CRS and its correlation with clinical outcome parameters are lacking. This study aimed to analyze the incidence, characteristics, risk factors, and early clinical impact of CRS during ATG/ATLG administration before allogeneic HSCT according to the American Society of Transplantation and Cellular Therapy (ASTCT) CRS grading criteria. This retrospective single-center analysis included consecutive recipients of allogeneic HSCT treated with ATG/ATLG as GVHD prophylaxis at the Medical University of Vienna between January 1, 2014, and August 15, 2021. Multivariate regression models were used to explore risk factors for CRS and its association with clinical outcomes (acute GVHD grade II-IV, clinically significant cytomegalovirus infection, nonrelapse mortality, and overall survival) at 6 months after HSCT. A total of 284 patients (median age, 54 years; interquartile range [IQR], 45 to 61 years; 120 females, 164 males) were included in the study. ATLG was used in 222 patients (78%); ATG, in 62 (22%). One hundred sixty-six patients (58%) developed CRS grade ≥1 during ATG/ATLG administration. CRS was mostly mild, with 92% of the cases CRS grade 1-2. Thirteen patients (5%) developed CRS grade 3, and 1 patient had CRS grade 4. No CRS-related death (grade 5) occurred. Patients with CRS showed a pronounced systemic inflammatory response as measured by inflammatory markers C-reactive protein, IL-6, and procalcitonin. In multivariate analysis, lymphoma as the underlying disease, high ATLG dose of 60 mg/kg, and body weight were significantly associated with CRS. Patients with CRS grade ≥1 had a higher 6-month incidence of acute GVHD II-IV compared with patients without CRS (24% versus 14%; P=.04). This effect remained statistically significant only for CRS grade 3-4 (subdistribution hazard ratio, 3.70; 95% confidence interval, 1.58 to 8.68; P < .01) after adjusting for relevant confounders. Other clinical outcome parameters were not affected by the occurrence of CRS. In our cohort, CRS defined by ASTCT grading was a frequent but mostly mild complication following ATG/ATLG administration for GVHD prophylaxis. Our data suggest a possible interaction of (higher-grade) CRS with an increased risk for developing acute GVHD. Further studies to corroborate this finding are warranted, as it could inform the investigation of additional prophylactic interventions, such as IL-6 blockade, in this setting.

Post-transplant cyclophosphamide in one-antigen mismatched unrelated donor transplantation versus haploidentical transplantation in acute myeloid leukemia: a study from the Acute Leukemia Working Party of the EBMT.

Whether to choose Haploidentical (Haplo) or one-antigen mismatched unrelated donor (1Ag-MMUD) hematopoietic cell transplantation (HCT) with post-transplant cyclophosphamide (PTCy) remains an unanswered question. We compared PTCy- Haplo-HCT to PTCy-1Ag-MMUD-HCT for acute myeloid leukemia (AML) in complete remission (three groups: 1Ag-MMUD using peripheral blood (1Ag-MMUD-PB; n = 155); Haplo using bone marrow (Haplo-BM; n = 647) or peripheral blood (Haplo-PB; n = 949)). Haplo-BM and Haplo-PB had a higher non-relapse mortality (NRM) compared to 1Ag-MMUD-PB (HR 2.28, 95% CI 1.23-4.24, p < 0.01; HR 2.65, 95% CI 1.46-4.81, p < 0.01, respectively). Haplo groups experienced a lower leukemia-free survival (LFS) compared to 1Ag-MMUD-PB (Haplo-BM: HR 1.51, 95% CI 1.06-2.14, p = 0.02; Haplo-PB: 1.47, 95% CI 1.05-2.05, p = 0.02); overall survival (OS) was also lower in Haplo-HCT (Haplo-BM: HR 1.50, 95% CI 1.02-2.21, p = 0.04; Haplo-PB: HR 1.51, 95% CI 1.05-2.19, p = 0.03). No differences were observed for graft-versus-host/relapse-free survival (GRFS) and relapse incidence (RI). Haplo-BM was associated with a lower risk of grade III-IV acute graft-versus-host disease (GVHD) (HR 0.44, 95% CI 0.24-0.81; p < 0.01), while no statistical differences were observed between groups for grade II-IV aGVHD and for cGVHD. Use of PTCy in 1Ag-MMUD-HCT is a valid alternative to consider when using alternative donors. Larger analysis of 1Ag-MMUD versus Haplo-HCT are warranted.

Risk of Cytomegalovirus Infection with Post-Transplantation Cyclophosphamide in Haploidentical and HLA-Matched Unrelated Donor Transplantation

Post-transplantation cyclophosphamide (PTCy) is effective for graft-versus-host disease (GVHD) prevention but is associated with an increased risk of cytomegalovirus (CMV) infection. The effect of PTCy on CMV infection in matched unrelated donor (MUD) hematopoietic stem cell transplantation (HSCT) is unclear, and whether there is any difference in CMV risk with 1 or 2 doses of PTCy is not well established. This study aimed to compare the incidence of CMV infection and the association between T cell recovery in patients who received PTCy-based GVHD prophylaxis and those who received non-PTCy-based GVHD prophylaxis. We conducted a retrospective study to compare the risk of CMV infection in 3 cohorts: cohort A (n=94), matched related donor (MRD)/MUD HSCT with calcineurin inhibitor-based GVHD prophylaxis; cohort B (n=103), MRD/MUD HSCT with 1 dose of PTCy, tacrolimus, and mycophenolate mofetil (MMF); and cohort C (n=28), haploidentical donor HSCT with 2 doses of PTCy, tacrolimus, and MMF. The day +100 cumulative incidence of CMV infection was 29% for cohort A, 39% for cohort B, and 61% for cohort C (P=.009), with no difference among the cohorts in the duration of viremia (P=.46). CD3+ and CD4+ T cell counts were significantly higher in cohort A at day +30 but not at days +60 and +90. Nonrelapse mortality (NRM) trended higher and relapse was significantly lower with PTCy. There was no difference in survival among the 3 cohorts. There is an increased risk of early CMV infection in patients receiving PTCy irrespective of donor type and number of PTCy doses compared with those not receiving PTCy. Strategies focusing on CMV prevention in PTCy recipients to mitigate the risk of NRM may lead to improved long-term outcomes.

Comparison of Quality of Life and Outcomes between Haploidentical and Matched Related/Unrelated Donor Allogeneic Hematopoietic Cell Transplantation

Haploidentical (haplo) donor grafts are a well-established alternative donor source for allogeneic hematopoietic cell transplantation (HCT); however, data comparing health-realted quality of life (HRQOL) measures between haplo-HCT and HCT using other donor sources are lacking. We hypothesized that post-transplantation HRQOL might not differ between haplo-HCT and HCT with other graft sources. We conducted a single-institution retrospective analysis comparing HRQOL of haplo-HCT with matched-related donor (MRD) HCT and matched unrelated donor (MUD) HCT for hematologic diseases. We included 90 haplo, 102 MRD, and 229 MUD adult first allogeneic HCTs performed between May 2014 and December 2019. HRQOL for haplo-HCT, MRD-HCT, and MUD-HCT were compared separately for myeloablative conditioning (MAC) and reduced-intensity conditioning (RIC). HRQOL was assessed using the Functional Assessment of Cancer Therapy-Bone Marrow Transplant (FACT-BMT) scale pretransplantation and at days +100 and +180 post-transplantation. MAC haplo-HCT showed no difference in all domains of HRQOL and other transplantation outcomes, including overall survival, compared with MAC MRD/MUD-HCT, except for a higher incidence of non-cytomegalovirus infections (P=.003). RIC haplo-HCT was associated with significantly better emotional well-being (P=.008) and functional well-being (P=.011) compared with MUD-HCT. RIC haplo-HCT was associated with higher rates of non-cytomegalovirus infections (P < .001) and relapse mortality (P=.044) but a lower rate of nonrelapse mortality (P=.008) compared with RIC MUD-HCT. Haplo-HCT had comparable total HRQOL scores and overall survival to MRD/MUD-HCT in both the MAC and RIC cohorts. Interrogation of HRQOL among disease-specific groups may further elucidate the existence of any additional benefits with these different transplantation modalities.

Matched unrelated donor hematopoietic stem cell transplant as a curative treatment for very early onset inflammatory bowel disease due to interleukin-10 receptor-B defect

Matched unrelated donor hematopoietic stem cell transplant as a curative treatment for very early onset inflammatory bowel disease due to interleukin-10 receptor-B defect

Unmanipulated haploidentical donor and matched unrelated donor hematopoietic stem cell transplantation in patients with paroxysmal nocturnal hemoglobinuria: a single-center study

We analyzed the outcomes of 32 patients with paroxysmal nocturnal hemoglobinuria (PNH) who underwent either a haploidentical donor (HID) or a matched unrelated donor (MUD) hematopoietic stem cell transplantation (HSCT). Seventeen patients received an HSCT from an HID and 15 patients received an HSCT from an MUD. The median follow-up time of the surviving patients was 36 months (range: 12–96 months). No significant differences were observed in the 3-year overall survival (OS) between the HID and MUD cohorts (74.1%±11.4% vs. 93.3%±6.4%, respectively, p=.222) or in the 3-year failure-free survival (68.8%±11.8% vs. 86.7%±8.8%, respectively, p=.307). Treatment-related mortality occurred in five patients. A univariate analysis of risk factors revealed platelet engraftment failure negatively impacted OS and FFS. We conclude that HID and MUD-HSCT are feasible and can be effective options for those PNH patients with concomitant bone marrow failure, recurrent life-threatening thrombosis, and uncontrollable hemolysis.

Unrelated donor α/β T cell– and B cell–depleted HSCT for the treatment of pediatric acute leukemia

Unrelated donor (URD) hematopoietic stem cell transplant (HSCT) is associated with an increased risk of severe graft-versus-host disease (GVHD). TCRαβ/CD19 depletion may reduce this risk, whereas maintaining graft-versus-leukemia. Outcome data with TCRαβ/CD19 depletion generally describe haploidentical donors, with relatively few URDs. We hypothesized that TCRαβ/CD19-depletion would attenuate the risks of GVHD and relapse for URD HSCT. Sixty pediatric and young adult (YA) patients with hematologic malignancies who lacked a matched-related donor were enrolled at 2 large pediatric transplantation centers between October 2014 and September 2019. All patients with acute leukemia had minimal residual disease testing, and DP typing was available for 77%. All patients received myeloablative total body irradiation– or busulfan-based conditioning with no posttransplant immune suppression. Engraftment occurred in 98%. Four-year overall survival was 69% (95% confidence interval [CI], 52%-81%), and leukemia-free survival was 64% (95% CI, 48%-76%), with no difference between lymphoid and myeloid malignancies (P = .6297 and P = .5441, respectively). One patient (1.7%) experienced primary graft failure. Relapse occurred in 11 patients (3-year cumulative incidence, 21%; 95% CI, 11-34), and 8 patients (cumulative incidence, 15%; 95% CI, 6.7-26) experienced nonrelapse mortality. Grade III to IV acute GVHD was seen in 8 patients (13%), and 14 patients (26%) developed chronic GVHD, of which 6 (11%) had extensive disease. Nonpermissive DP mismatch was associated with higher likelihood of acute GVHD (odds ratio, 16.50; 95% CI, 1.67-163.42; P = .0166) but not with the development of chronic GVHD. URD TCRαβ/CD19-depleted peripheral HSCT is a safe and effective approach to transplantation for children/YAs with leukemia. This trial was registered at www.clinicaltrials.gov as #NCT02323867.

Outcome of allogeneic transplantation for mature T-cell lymphomas: impact of donor source and disease characteristics

AbstractMature T-cell lymphomas constitute the most common indication for allogeneic hematopoietic cell transplantation (allo-HCT) of all lymphomas. Large studies evaluating contemporary outcomes of allo-HCT in mature T-cell lymphomas relative to commonly used donor sources are not available. Included in this registry study were adult patients who had undergone allo-HCT for anaplastic large cell lymphoma, angioimmunoblastic T-cell lymphoma (AITL), or peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) between 2008 and 2018. Hematopoietic cell transplantation (HCT) platforms compared were posttransplant cyclophosphamide-based haploidentical (haplo-)HCT, matched sibling donor (MSD) HCT, matched unrelated donor HCT with in vivo T-cell depletion (MUD TCD+), and matched unrelated donor HCT without in vivo T-cell depletion (MUD TCD−). Coprimary end points were overall survival (OS) and progression-free survival (PFS); secondary end points included nonrelapse mortality (NRM), and relapse/progression incidence (RI). A total of 1942 patients were eligible (237 haplo-HCT; 911 MSD; 468 MUD TCD+; 326 MUD TCD−). Cohorts were comparable for baseline characteristics with the exception of higher proportions of patients with decreased performance status (PS) and marrow graft recipients in the haplo-HCT group. Using univariate and multivariate comparisons, OS, PFS, RI, and NRM were not significantly different among the haplo-HCT, MSD, MUD TCD+, and MUD TCD− cohorts, with 3-year OS and PFS of 60%, 63%, 59%, and 64%, respectively, and 50%, 50%, 48%, and 52%, respectively. Significant predictors of inferior OS and PFS on multivariate analysis were active disease status at HCT and decreased PS. AITL was associated with significantly reduced relapse risk and better PFS compared with PTCL-NOS. Allo-HCT can provide durable PFS in patients with mature T-cell lymphoma (TCL). Outcomes of haplo-HCT were comparable to those of matched donor allo-HCT.

Management of Peripheral T-Cell Lymphoma in Children and Adolescents Including STAT 3 Mutation Hyper-IgE Syndrome: One Size Does Not Fit All.

Peripheral T-cell lymphoma (PTCL) is a rare form of lymphoma in children with limited published data on treatment and lack of a uniformly accepted treatment algorithm. We retrospectively analyzed the data in children up to 18 years of age diagnosed to have PTCL from January 2016 to June 2020. The study included six children with a median age of 10 years, the youngest being a 7-month-old girl. According to the WHO-PTCL classification, three had PTCL-not otherwise specified (NOS), 2 had hepatosplenic TCL, and 1 had subcutaneous panniculitis-like TCL. All children had presented with advanced disease, 4 in St. Jude stage IV, 2 in St. Jude stage III. Three children received CHOEP chemotherapy including cyclophosphamide, doxorubicin, vincristine, prednisone, etoposide, while 1 child received CHOP. Two children received induction as per acute lymphoblastic leukemia followed by Bendamustine. Two patients succumbed to progressive disease, the infant with PTCL-NOS and 1 child with hepatosplenic TCL. Three children were in remission (median follow up of 44 mo). One child with PTCL-NOS Stage IV had an underlying STAT3 mutated hyperimmunoglobulin E syndrome and was in remission 12 months post a matched unrelated donor hematopoietic stem cell transplantation. He had grade 4 skin graft versus host disease and required extracorporeal photopheresis and ibrutinib, to which he had responded. CHOEP chemotherapy is well-tolerated and subcutaneous panniculitis-like TCL has the best prognosis thus far.

Optimal Donor Selection for Hematopoietic Cell Transplantation Using Bayesian Machine Learning.

Donor selection practices for matched unrelated donor (MUD) hematopoietic cell transplantation (HCT) vary, and the impact of optimizing donor selection in a patient-specific way using modern machine learning (ML) models has not been studied. We trained a Bayesian ML model in 10,318 patients who underwent MUD HCT from 1999 to 2014 to provide patient- and donor-specific predictions of clinically severe (grade 3 or 4) acute graft-versus-host disease or death by day 180. The model was validated in 3,501 patients from 2015 to 2016 with archived records of potential donors at search. Donor selection optimizing predicted outcomes was implemented over either an unlimited donor pool or the donors in the search archives. Posterior mean differences in outcomes from optimal donor selection versus actual practice were summarized per patient and across the population with 95% intervals. Event rates were 33% (training) and 37% (validation). Among donor features, only age affected outcomes, with the effect consistent regardless of patient features. The median (interquartile range) difference in age between the youngest donor at search and the selected donor was 6 (1-10) years, whereas the number of donors per patient younger than the selected donor was 6 (1-36). Fourteen percent of the validation data set had an approximate 5% absolute reduction in event rates from selecting the youngest donor at search versus the actual donor used, leading to an absolute population reduction of 1% (95% interval, 0 to 3). We confirmed the singular importance of selecting the youngest available MUD, irrespective of patient features, identified potential for improved HCT outcomes by selecting a younger MUD, and demonstrated use of novel ML models transferable to optimize other complex treatment decisions in a patient-specific way.

Post-Transplant Cyclophosphamide Is Associated with Improved Clinical Outcomes in HLA-Mismatched Unrelated Donor Hematopoietic Cell Transplantation

Post-Transplant Cyclophosphamide Is Associated with Improved Clinical Outcomes in HLA-Mismatched Unrelated Donor Hematopoietic Cell Transplantation

Randomized Trial of Tacrolimus and Methotrexate Versus Tacrolimus, Reduced Dose Methotrexate, and Mycophenolate Mofetil for Prevention of Graft-Versus-Host Disease after Myeloablative Related and Unrelated Donor Allogeneic Hematopoietic Cell Transplantation

Background: Graft-versus-host disease (GVHD) remains a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). The combination of tacrolimus (Tac) and methotrexate (MTX) is a standard regimen for GVHD prophylaxis; however, it is associated with several toxicities and patients are often not able to complete the full MTX regimen. The combination of Tac, reduced dose (“mini”)-MTX, and mycophenolate mofetil (MMF) has been investigated with a well-tolerated toxicity profile and low incidence of GVHD, although comparison with standard dose MTX has not been done. We performed a randomized non-inferiority trial comparing Tac/MTX (Full-MTX) to Tac/mini-MTX/MMF (Mini-MTX) for prevention of GVHD after myeloablative related and unrelated donor HCT.Methods: Patients <70 years in age receiving first myeloablative allogeneic HCT using 8/8 HLA-matched related or unrelated donor were eligible; all diagnoses and both bone marrow and peripheral blood stem cell grafts were allowed. Full-MTX patients received MTX dose of 15 mg/m 2 day +1, and 10 mg/m 2 days +3, +6, and +11. Mini-MTX patients received doses of 5 mg/m 2 on days +1, +3, and +6 plus MMF 1000 mg BID. MTX and MMF doses were adjusted for body weight in pediatric recipients. Primary endpoints were incidence of acute GVHD, mucositis, and hematopoietic engraftment. Secondary endpoints included incidence of chronic GVHD, organ toxicity, infection, relapse, non-relapse mortality (NRM), and overall survival (OS). Based on our local incidence rates, 45 patients/arm were needed to detect a hazard ratio of at most 1.7 for acute GVHD (no difference between two arms) using a one-sided non-inferiority log-rank test with 5% significance and 80% power.Results: We enrolled 101 patients; 5 were excluded due to change in eligibility or withdrawal of consent prior to HCT. Analysis is based on 96 patients who were randomized to receive Full-MTX (N=49) or Mini-MTX (N=47). Patient characteristics are described in the Table, and were generally balanced between the two groups . All patients in the Mini-MTX arm received their 3 planned doses of MTX; in the Full-MTX arm, 71% received all 4 doses, 26% received 3 doses, and 1 patient received 2 doses of MTX. There was no significant difference in cumulative incidence of grade 2-4 acute GVHD by day 100 between arms (28% Mini-MTX vs 27% Full-MTX, P=0.41) (Figure 1); however, there was a trend toward higher grade 3-4 acute GVHD in Mini-MTX arm (13% vs 4%, P=0.07). Mini-MTX recipients had lower incidence of severe WHO grade 3-4 mucositis (57% vs 82%, P=0.010), shorter duration of mucositis (median 11 vs 18 days, P<0.001), and had faster engraftment of both neutrophils (median 15 vs 17 days, P<0.001) and platelets (median 23 vs 27 days, P=0.023), with resultant shorter hospital stay (median 27 vs 31 days, P<0.001). There were no significant differences between the two arms in any grade of chronic GVHD (36% vs 25%, P=0.09) or moderate-severe chronic GVHD at 1 year (23% vs 20%, P=0.14). There were also no differences in bacterial (P=0.18), viral (P=0.52) or fungal (P=0.74) infections. There were no significant differences in hepatotoxicity, but lower proportion of patients receiving Mini-MTX experienced nephrotoxicity (creatinine ≥3X upper limit of normal: 2% vs 26%, P<0.001). Mini-MTX recipients also had less respiratory failure in the first 6 months (6% versus 22%, P=0.026). There was no difference in relapse between arms (2-year incidence 22% vs 21%, P=0.89), although Mini-MTX was associated with lower NRM (11% vs 25% at 2 years) (Figure 2), and non-significant but higher OS (70% vs 52% at 2 years; P=0.06).Conclusions: Compared to Full-MTX, a Mini-MTX regimen that incorporates MMF was associated with no difference in acute or chronic GVHD incidence and a more favorable toxicity profile, with faster engraftment, less mucositis, less organ toxicity, and lower NRM. The combination of Tac/mini-MTX/MMF is an acceptable alternative to Tac/MTX after myeloablative related and unrelated donor HCT. [Display omitted] DisclosuresHamilton: Syndax: Membership on an entity's Board of Directors or advisory committees; Equilium: Membership on an entity's Board of Directors or advisory committees. Gerds: Imago: Research Funding; AbbVie: Consultancy; Constellation: Consultancy; Brystol Myers Squibb: Consultancy; Sierra Oncology: Consultancy; Incyte: Research Funding; PharmaEssentia: Consultancy; Novartis: Consultancy; Constellation: Research Funding; Krtos: Research Funding; CTI Biopharma: Research Funding; Accutate: Research Funding. Hill: Gentenech: Consultancy, Honoraria, Research Funding; AstraZenica: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Research Funding; Celgene (BMS): Consultancy, Honoraria, Research Funding; Epizyme: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Beigene: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Incyte/Morphysis: Consultancy, Honoraria, Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Other: Travel Support, Research Funding. Copelan: Amgen: Consultancy. Majhail: Anthem, Inc: Consultancy; Incyte Corporation: Consultancy.

Comparative Study of Unrelated and Haploidentical Donor Hematopoietic Cell Transplant for Chronic Myeloid Leukemia with Post Transplant Cyclophosphamide As Graft-Versus-Host Disease Prophylaxis: A Study from the Chronic Malignancies Working Party of EBMT

Comparative Study of Unrelated and Haploidentical Donor Hematopoietic Cell Transplant for Chronic Myeloid Leukemia with Post Transplant Cyclophosphamide As Graft-Versus-Host Disease Prophylaxis: A Study from the Chronic Malignancies Working Party of EBMT

Donor Killer Immunoglobulin Receptor Gene Content and Ligand Matching and Outcomes of Pediatric Patients with Juvenile Myelomonocytic Leukemia Following Unrelated Donor Transplantation

Natural killer (NK) cell determinants predict relapse-free survival after allogeneic hematopoietic cell transplantation (HCT) for acute myelogenous leukemia, and previous studies have shown a beneficial graft-versus-leukemia effect in patients with juvenile myelomonocytic leukemia (JMML). However, whether NK cell determinants predict protection against relapse for JMML patients undergoing HCT is unknown. Therefore, we investigated NK cell-related donor and recipient immunogenetics as determinants of HCT outcomes in patients with JMML. Patients with JMML (age 0 to <19 years) who underwent a first allogeneic HCT from an unrelated donor between 2000 and 2017 and had available donor samples from the Center for International Blood and Marrow Transplant Research Repository were included. Donor killer immunoglobulin receptor (KIR) typing was performed on pre-HCT samples. The primary endpoint was disease-free survival (DFS); secondary endpoints included relapse, grade II-IV acute graft versus-host-disease (aGVHD), chronic GVHD (cGVHD), GVHD-free relapse-free survival, transplantation-related mortality, and overall survival (OS). Donor KIR models tested included KIR genotype (AA versus Bx), B content (0-1 versus ≥2), centromeric and telomeric region score (AA versus AB versus BB), B content score (best, better, or neutral), composite score (2 versus 3 versus 4), activating KIR content, and the presence of KIR2DS4. Ligand-ligand and KIR-ligand mismatch effects on outcomes were analyzed in HLA-mismatched donors (≤7/8; n=74) only. Univariate analyses were performed for primary and secondary outcomes of interest, with a P value <.05 considered significant. One hundred sixty-five patients (113 males), with a median follow-up of 85 months (range, 6 to 216 months) met the study criteria. Of these, 111 underwent an unrelated donor HCT and 54 underwent a UCB HCT. Almost all (n=161; 98%) received a myeloablative conditioning regimen. After exclusion of recipients of reduced-intensity/nonmyeloablative conditioning regimens and ex vivo T cell-depleted grafts (n=8), there were 42 AA donors and 115 Bx donors, respectively. Three-year DFS, OS, relapse, and GRFS for the entire cohort were 58% (95% confidence interval [CI], 50% to 66%), 67% (95% CI, 59% to 74%), 26% (95% CI, 19% to 33%), and 27% (95% CI, 19% to 35%), respectively. The cumulative incidence of grade II-IV aGVHD at 100 days was 36% (95% CI, 27% to 44%), and that of cGVHD at 1 year was 23% (95% CI, 17% to 30%). There were no differences between AA donors and Bx donors for any recipient survival outcomes. The risk of grade II-IV aGVHD was lower in patients with donors with a B content score of ≥2 (hazard ratio [HR], 0.46; 95% CI, 0.26 to 0.83; P=.01), an activating KIR content score of >3 (HR, 0.52; 95% CI, 0.29 to 0.95; P=.032), centromeric A/B score (HR, 0.57; 95% CI, 033 to 0.98; P=.041), and telomeric A/B score (HR, 0.58; 95% CI, 0.34 to 1.00; P=.048). To our knowledge, this is the first study analyzing the association of NK cell determinants and outcomes in JMML HCT recipients. This study identifies potential benefits of donor KIR-B genotypes in reducing aGVHD. Our findings warrant further study of the role of NK cells in enhancing the graft-versus-leukemia effect via recognition of JMML blasts.

Prognostic impact of pre-transplant chromosomal aberrations in peripheral blood of patients undergoing unrelated donor hematopoietic cell transplant for acute myeloid leukemia

To improve risk stratification and treatment decisions for patients with acute myeloid leukemia (AML) undergoing hematopoietic cell transplantation (HCT). We used SNP-array data from the DISCOVeRY-BMT study to detect chromosomal aberrations in pre-HCT peripheral blood (collected 2–4 weeks before the administration of conditioning regimen) from 1974 AML patients who received HCT between 2000 and 2011. All aberrations detected in ≥ 10 patients were tested for their association with overall survival (OS), separately by remission status, using the Kaplan–Meier estimator. Cox regression models were used for multivariable analyses. Follow-up was through January 2019. We identified 701 unique chromosomal aberrations in 285 patients (7% of 1438 in complete remission (CR) and 36% of 536 not in CR). Copy-neutral loss-of-heterozygosity (CNLOH) in chr17p in CR patients (3-year OS = 20% vs. 50%, with and without chr17p CNLOH, p = 0.0002), and chr13q in patients not in CR (3-year OS = 4% vs. 26%, with and without chr13q CNLOH, p < 0.0001) are risk factors for poor survival. Models adjusted for clinical factors showed approximately three-fold excess risk of post-HCT mortality with chr17p CNLOH in CR patients (hazard ratio, HR = 3.39, 95% confidence interval CI 1.74–6.60, p = 0.0003), or chr13q CNLOH in patients not in CR (HR = 2.68, 95% CI 1.75–4.09, p < 0.0001). The observed mortality was mostly driven by post-HCT relapse (HR = 2.47, 95% CI 1.01–6.02, p = 0.047 for chr17p CNLOH in CR patients, and HR = 2.58, 95% CI 1.63–4.08, p < 0.0001 for chr13q CNLOH in patients not in CR. Pre-transplant CNLOH in chr13q or chr17p predicts risk of poor outcomes after unrelated donor HCT in AML patients. A large prospective study is warranted to validate the results and evaluate novel strategies to improve survival in those patients.

Cytotoxic T Lymphocyte Antigen 4 (CTLA4) Single Nucleotide Polymorphisms Do Not Impact Outcomes After Unrelated Donor Transplant: A Center For International Blood and Marrow Transplant Research Analysis

Cytotoxic T Lymphocyte Antigen 4 (CTLA4) is a critical T cell molecule that inhibits T cell activation and plays an essential role in T cell homeostasis and immune responses. Genetic variations in the CTLA4 gene have been hypothesized to be possible biologic markers that are predictive of transplant outcomes. Previous investigators have studied single nucleotide polymorphisms (SNPs) of the CTLA4 gene and its impact on hematopoietic cell transplantation (HCT) outcomes with discordant results. AA and AG genotypes in the donor CTLA4 regulatory region involving SNP rs4553808 in patients after unrelated donor (URD) HCT have recently been shown to be an independent predictor of improved relapse free survival (RFS) and overall survival (OS) compared to the GG genotype. To validate these preliminary findings, a Center for International Blood and Marrow Research (CIBMTR) study was performed in a larger, more homogenous cohort of patients.Adult patients with acute myeloid leukemia (AML) and advanced myelodysplastic syndrome (MDS) undergoing a first 8/8 or 7/8 HLA matched URD HCT after myeloablative, non-myeloablative, or reduced intensity conditioning from 2002 to 2007 in first or second complete remission with available donor research samples from the National Marrow Donor Program research repository were included. The primary goal was to evaluate the impact of SNP rs4553808 on RFS, OS, and NRM and the cumulative incidence of acute graft-versus-host disease (aGVHD), and chronic graft-versus-host disease (cGVHD). Any GVHD prophylaxis could be used except in vitro T-cell depletion or use of in vivo/in vitro alemtuzumab. Patients receiving T cell depletion with anti-thymocyte globulin (ATG) were oversampled to allow analysis of any effects on outcomes. An exploratory analysis of 9 other tagSNPs that encompass the entire CTLA4 gene (rs231775, rs231779, rs11571315, rs231777, rs3087243, rs16840252, rs231725, rs10197010, rs11571316) was performed to evaluate for any additional potential associations with clinical outcomes.Each SNP was analyzed in multivariable models adjusting for clinically significant variables using the Cox proportional hazards model. Due to multiple testing, p-values <0.005 were considered significant. The interaction with CTLA4 SNPs and use of ATG was also specifically analyzed. The final analysis included 780 patients with a median followup of 63 months. Median age of recipients and donors was 50 and 34, respectively. 90% of recipients were identified to be of Caucasian descent (N=709). 80% of patients had AML (N=624) and 20% MDS (N=156). Conditioning was 61% ablative, 28% reduced intensity and 11% non-myeloablative, with 74% receiving peripheral blood grafts. 75% were HLA-matched and 25% single locus mismatched. Tacrolimus with methotrexate or mycophenolate mofetil GVHD prophylaxis was given to 62%, cyclosporine-based prophylaxis to 15% while 23% received other regimens. By design, 50% of patients received ATG. Genotyping showed that 552 (71%) were AA, 208 (27%) were AG and 19 (2%) were GG (AG, and particularly GG, were associated with worse outcomes in the prior study). Multivariable analysis adjusting for significant donor and recipient characteristics showed no significant association between SNP rs4553808 and OS (p=0.07), RFS (p=0.41), NRM (p=0.25), and incidence of acute and chronic GVHD (Figure 1). Multivariable analysis of the other 9 tagSNPs also showed no association with transplant outcomes (p>0.005). No interaction was found between the CTLA4 SNPs and use of ATG on outcomes. These results indicate that CTLA4 SNPS do not have impact on outcomes. Other genomic or cellular biomarkers need to be studied to risk stratify patients at high risk of negative clinical events, especially as therapies targeting CTLA4 and PD-1 evolves. [Display omitted] [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Increased donor inhibitory KIR with known HLA interactions provide protection from relapse following HLA matched unrelated donor HCT for AML.

Killer immunoglobulin-like receptor (KIR) and KIR-ligand (KIRL) interactions play an important role in natural killer cell-mediated graft versus leukemia effect (GVL) after hematopoietic cell transplant (HCT) for AML. Accounting for known KIR-KIRL interactions may identify donors with optimal NK cell-mediated alloreactivity and GVL. A retrospective study of 2359 donor-recipient pairs (DRP) who underwent unrelated donor (URD) HCT for AML was performed. KIR-KIRL combinations were determined and associations with clinical outcomes examined. Relapse risk was reduced in DRP with both higher inhibitory KIR-KIRL (iKIR) and missing KIRL (mKIR) scores, with HR 0.86 (P = 0.01) & HR 0.84 (P = 0.02) respectively. The iKIR and mKIR score components were summed to give a maximal inhibitory KIR ligand (IM-KIR) score for each donor, which if it was 5, as opposed to <5, was also associated with a lower relapse risk, SHR 0.8 (P = 0.004). All IM = 5 donors possess KIR Haplotype B/x. Transplant-related mortality was increased among those with IM-KIR = 5, HR, 1.32 (P = 0.01). In a subset analysis of those transplanted with 8/8 HLA-matched DRP, anti-thymocyte globulin recipients with IM-KIR = 5, had a lower relapse rate HR, 0.61 (p = 0.001). This study demonstrates that HLA-matched unrelated donors with the highest inhibitory KIR content confer relapse protection, albeit with increased TRM. These donors all have KIR haplotype B. Clinical trials utilizing donors with a higher iKIR content in conjunction with novel strategies to reduce TRM should be considered for URD HCT in recipients with AML to optimize clinical outcomes.

Matched Unrelated Donor Attrition in a Stem Cell Registry

Background and Objective: Increment in voluntary stem cell donor registrations has led to an increase in the chances of a patient finding a perfect match for matched unrelated donor (MUD) hematopoietic stem cell (HSC) transplant. However, it has been seen multiple times that the donor's passion to donate HSCs is short lived. They register with a strong commitment, however, when they are approached to donate, they back out. This write-up is an attempt to quantify and analyze the rate and reasons of MUD deferral in a stem cell registry from North India. Methods: Registered volunteer stem cell donors who backed out after getting matched were interviewed to understand the reasons behind their deferral. Key steps taken for sustaining the passion of registered donors included amendments in the donor recruitment process and maintaining constant communication with the recruited donors. Results: The attrition rate of the registry for final donation during the studied period was 22.91%. A total of 22 cases of donor deferral were observed. Among these, 15 donors (68.19%) who backed out were female and 7 (31.81%) were male. There were three main reasons observed behind this attrition, namely personal reasons, medical reasons from the donor side, and medical reasons from the patient side. Conclusion: To minimize donor deferral, various new strategies could be implemented such as requesting the participation of experienced donors in counseling sessions, requesting guardian's involvement in case the donor is a teen or is in their early twenties (between 18 and 25 years), and requesting the name of the person they consulted before signing up for donation.