HLA-matched Bone Marrow Transplantation Research Articles

Interim Results of a Phase I/II Study of Intermediate-Dose Post-Transplantation Cyclophosphamide after Reduced Intensity Conditioned HLA-Matched Bone Marrow Transplantation for Older or Infirm Patients

Interim Results of a Phase I/II Study of Intermediate-Dose Post-Transplantation Cyclophosphamide after Reduced Intensity Conditioned HLA-Matched Bone Marrow Transplantation for Older or Infirm Patients

Systematic overview of HLA-matched allogeneic hematopoietic cell transplantation with post-transplantation cyclophosphamide.

The successful application of post-transplantation cyclophosphamide (PTCy) as graft-versus-host disease (GVHD) prophylaxis in HLA-haploidentical allogeneic hematopoietic cell transplantation (allo-HCT) led to the expansion of its application to HLA-matched related and unrelated allo-HCT. Notably, single-agent PTCy was found to be feasible for GVHD prevention in HLA-matched bone marrow transplantation. Single-agent PTCy prophylaxis was later attempted to control GVHD in HLA-matched peripheral blood stem cell transplantation (PBSCT), but this approach was inadequate to alleviate GVHD as evidenced by the high incidence of severe GVHD and/or non-relapse mortality. Therefore, various combinations of immunosuppressants with PTCy have been explored to identify the optimal drug combination that would efficiently prevent GVHD in HLA-matched PBSCT. A recent murine study helped clarify the putative mechanism underlying the activity of PTCy, demonstrating that PTCy impairs the proliferation and function of alloreactive T cells from the donor, but does not eliminate alloreactive T cells altogether. In addition, imbalanced reconstitution of NK cell as well as T cells has been observed in HLA-haploidentical allo-HCT. Therefore, it remains unclear whether or not PTCy-containing GVHD prophylaxis should replace the classical GVHD prophylaxis regimen in the HLA-matched setting, and convincing evidence supporting the benefits of PTCy is needed.

High Failure-Free Survival after Unrelated Donor Peripheral Blood Stem Cell Transplantation in Pediatric Severe Aplastic Anemia

The use of alternative donor peripheral blood stem cell transplantation (PBSCT) has increased in recent years. In this study, we analyzed the effect of stem cell source and HLA disparity on outcomes in pediatric patients with severe aplastic anemia (SAA). A total of 134 patients who underwent HSCT with nonmyeloablative conditioning between 2006 and 2020 were enrolled and classified into 3 groups: HLA-matched bone marrow transplantation (M-BMT; n = 24), HLA-matched PBSCT (M-PBSCT; n = 66), and HLA-mismatched PBSCT (MM-PBSCT; n = 44). Significantly higher stem cell doses were obtained for PBSCT than for BMT. A total of 13 patients experienced secondary graft failure (GF), with a cumulative incidence (CI) of 10.0%. HLA-mismatched PBSCT and a very severe degree of disease significantly decreased the incidence of secondary GF. The CI of grade II-IV acute graft-versus-host disease (GVHD) was significantly higher in PBSCT than in BMT, but the CI of grade III-IV acute GVHD and CI of chronic GVHD requiring systemic treatment did not increase in PBSCT. The estimated 5-year overall survival (OS), failure-free survival (FFS), and GVHD-free failure-free survival (GFFS) of the total cohort were 93.0%, 89.5%, and 77.5%, respectively. The most favorable FFS was observed in the MM-PBSCT group (97.6%; P = .03), whereas OS and GFFS were similar across the 3 groups. In multivariate analysis, HLA mismatch and short time from diagnosis to transplantation were associated with superior FFS. Unrelated donor PBSCT with low-intensity SAA conditioning showed favorable outcomes in terms of low rate of secondary GF, higher FFS, and manageable GVHD regardless of HLA compatibility. Our findings suggest the feasibility of PBSCT from unrelated donors, resulting in the possible expansion of the donor pool in transplantation for pediatric SAA. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Signatures of GVHD and relapse after posttransplant cyclophosphamide revealed by immune profiling and machine learning

AbstractThe key immunologic signatures associated with clinical outcomes after posttransplant cyclophosphamide (PTCy)-based HLA-haploidentical (haplo) and HLA-matched bone marrow transplantation (BMT) are largely unknown. To address this gap in knowledge, we used machine learning to decipher clinically relevant signatures from immunophenotypic, proteomic, and clinical data and then examined transcriptome changes in the lymphocyte subsets that predicted major posttransplant outcomes. Kinetics of immune subset reconstitution after day 28 were similar for 70 patients undergoing haplo and 75 patients undergoing HLA-matched BMT. Machine learning based on 35 candidate factors (10 clinical, 18 cellular, and 7 proteomic) revealed that combined elevations in effector CD4+ conventional T cells (Tconv) and CXCL9 at day 28 predicted acute graft-versus-host disease (aGVHD). Furthermore, higher NK cell counts predicted improved overall survival (OS) due to a reduction in both nonrelapse mortality and relapse. Transcriptional and flow-cytometric analyses of recovering lymphocytes in patients with aGVHD identified preserved hallmarks of functional CD4+ regulatory T cells (Tregs) while highlighting a Tconv-driven inflammatory and metabolic axis distinct from that seen with conventional GVHD prophylaxis. Patients developing early relapse displayed a loss of inflammatory gene signatures in NK cells and a transcriptional exhaustion phenotype in CD8+ T cells. Using a multimodality approach, we highlight the utility of systems biology in BMT biomarker discovery and offer a novel understanding of how PTCy influences alloimmune responses. Our work charts future directions for novel therapeutic interventions after these increasingly used GVHD prophylaxis platforms. Specimens collected on NCT0079656226 and NCT0080927627 https://clinicaltrials.gov/.

Grade II Acute Gvhd Improves Progression-Free Survival after Myeloablative HLA-Matched Bone Marrow Transplant with Posttransplantation Cyclophosphamide

Introduction: Posttransplant cyclophosphamide (PTCy) can be safely utilized as the sole graft-versus-host-disease (GVHD) prophylaxis after myeloablative conditioning (MAC) for HLA-matched bone marrow transplant (BMT). However, the effects of GVHD with this transplant platform are not well defined. Methods: We retrospectively analyzed 298 consecutive adult patients transplanted between 2004-2012 for hematologic malignancy who engrafted after MAC (busulfan with either fludarabine or Cy) HLA-matched related (MRD, n=187) or HLA-matched unrelated (MUD, n=111) T-cell-replete BMT with Cy 50 mg/kg on days 3 and 4. Results: Median recipient age was 48 and 47 years for MAC MRD and MUD BMT, respectively. Median follow up was 4.33 and 3.74 years in the two cohorts, respectively. After MAC MRD BMT, 35% of patients experienced grade II acute (a) GVHD, 12% grade III-IV aGVHD, and 9% chronic (c) GVHD. After MAC MUD BMT, 54% of patients experienced grade II aGVHD, 17% grade III-IV aGVHD, and 17% cGVHD. We choose landmark analyses that look at the time to an event after a pre-specified time point. By starting the failure-time clock later, one can regard events prior to the landmark as baseline factors in the analysis, allowing us to study the effects of a posttransplant event on subsequent outcomes. We selected landmark time points at 100 days and 1 year, which allowed us to capture 100% of the patients who developed maximal grade II aGVHD and 97% of the patients who developed cGVHD. Few patients died of acute or chronic GVHD before their respective landmark time points. In landmark analyses at 100 days after MAC MRD BMT, 4-year overall survival (OS) and progression-free survival (PFS) were 60% (95% CI: 0.50-0.72) and 41% (95% CI: 0.30-0.54) in patients without grade II-IV aGVHD, and 67% (95% CI: 0.55-0.82) and 56% (95% CI: 0.43-0.73) in patients with maximal grade II aGVHD (Figure 1). In landmark analyses at 100 days after MAC MUD BMT, 4-year OS and PFS were 51% (95% CI: 0.36-0.73) and 44% (95% CI: 0.28-0.69) in patients without grade II-IV aGVHD, and 65% (95% CI: 0.52-0.82) and 45% (95% CI: 0.31-0.64) in patients with grade II aGVHD. In landmark analysis at 1 year after MAC MRD BMT, 4-year OS and PFS were 77% (95% CI: 0.67-0.89) and 60% (95% CI: 0.46-0.77) in patients without GVHD, and 69% (95% CI: 0.45-1) and 75% (95% CI: 0.5-1) in patients with cGVHD. In landmark analysis at 1 year after MAC MUD BMT, 4-year OS and PFS were 57% (95% CI: 0.39-0.82) and 57% (95% CI: 0.36-0.90) in patients without GVHD, and 90% (95% CI: 0.73-1) and 75% (95% CI: 0.5-1) in patients with cGVHD. In time-dependent multivariable analyses adjusted for disease risk index, recipient age, and hematopoietic cell transplant-comorbidity index (HCT-CI), grade II aGVHD was associated with improved OS and PFS after both MAC MRD (HR 0.56 95% CI 0.3-1.05, p=.07 and HR 0.59 95% CI 0.35-0.99, p=.05, respectively) and MAC MUD BMT (HR 0.53 95% CI 0.26-1.06, p=.07 and HR 0.47 95% CI 0.25-0.91, p=.03, respectively). In contrast, after MAC MRD, grade III-IV aGVHD was associated with decreased OS (HR 2.25 95% CI 1.18-4.29, p=.01) with no significant difference in PFS (HR 1.5 95% CI 0.8-2.81, p=.20). In contrast to the univariable analysis, chronic GVHD was not significantly associated with OS or PFS in MAC MRD (HR 1.18 95% CI: 0.52-2.69, p=.69 and HR 0.77 95% CI: 0.34-1.74, p=.53) or MAC MUD (HR 0.73 95% CI: 0.27-1.97, p=.53 and HR 0.67 95% CI: 0.28-1.65, p=.39) BMT. Increasing nucleated cell graft dose as a continuous variable was associated with improved PFS after MAC MRD and MAC MUD BMT (HR 0.85 95% CI 0.71-1.01, p=.06 and HR 0.83 95% CI 0.69-1.0, p=.05, respectively). Conclusion: Development of maximal grade II aGVHD was associated with significantly improved PFS after HLA-matched BMT with PTCy. In this distinct cohort, we validated prior work from our group, which showed that grade II aGVHD improves PFS after nonmyeloablative HLA-haploidentical BMT with PTCy, mycophenolate mofetil, and tacrolimus (McCurdy et al. 2017 submitted for publication). This suggests that, in the setting of PTCy, grade II aGVHD improves PFS. Therefore intensifying GVHD prophylaxis to reduce grade II aGVHD may not improve transplant outcomes. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION IN FANCONI ANEMIA; A SINGLE CENTRE EXPERIENCE

Objective: To determine the treatment outcome of Hematopoietic stem cell transplantation in Fanconi Anemia.
 Study Design: Case series.
 Place and Duration of Study: Armed Forces Bone Marrow Transplant Center, Rawalpindi, from Jan 2001 to Jun 2018.
 Methodology: Data of all Fanconi anemia patients who had fully HLA matched bone marrow transplant during this period was analysed for variables affecting the outcome in terms of overall survival. Those fanconi anemia patients who had myelodysplastic changes or acute myeloid leukemia were excluded.
 Results: Total 27 patients underwent fully HLA matched allogeneic bone marrow transplant for Fanconi Anemia. Mean age of patients at transplant was 12.12 ± 5.16 years. All patients at transplant were in aplastic phase. Conditioning was done with fludarabine 120mg/m2 , ATG 20 mg/kg and Cyclophosphamide at a dose of 20-40 mg/kg. Mean time to neutrophil engraftment was 12.3 ± 2.92days and for platelets 20 ± 10.3 days. Major posttransplant complications were neutropenic fever in 26 (96%), hypertension in 18 (66.6%), mucositis in 12 (44.4%), azotaemia in 8 (29.6%), gut toxicity in 7 (25.9%) and haemorrhagic cystitis in 5 (18.5%) patients. Four patients (14.8%) had acute graft versus host disease while 7 (26%) patients had chronic GVHD. Overall survival at 6 months, 1, 5 and 8 years was 67%, 63%, 59% and 55% respectively. While overall survival in patients transplanted at younger age (<11 years) was 81.8% compared to 37.5% in older age group (>11years) and was statistically significant (p-value = 0.03).
 Conclusion: Our study demonstrated...................

Donor UNC-93 Homolog B1 genetic polymorphism predicts survival outcomes after unrelated bone marrow transplantation.

UNC-93 homolog B1 (UNC93B1) is a key regulator of toll-like receptors (TLRs), pattern recognition receptors that sense invading pathogens and manage the innate immune response and deliver them from the endoplasmic reticulum to their respective endosomal signaling compartments. Several types of TLRs are known to contribute to the inflammatory process after allogeneic hematopoietic stem cell transplantation (SCT), so UNC93B1 might play integral roles there. We investigated the influence of the UNC93B1 single-nucleotide polymorphism (SNP) rs308328 (T>C) on transplant outcomes in a cohort of 237 patients undergoing unrelated HLA-matched bone marrow transplantation (BMT) for hematologic malignancies through the Japan Marrow Donor Program. The donor UNC93B1 C/C genotype was associated with a better 3-year overall survival than the donor UNC93B1 C/T or T/T genotype. An analysis of the UNC93B1 rs308328 genotype may therefore be useful for selecting the donor, estimating the prognosis, and creating therapeutic strategies after allogeneic SCT.

A Machine Learning Approach Deciphers the Effects of Immune Parameters on Clinical Outcomes after HLA-Haploidentical and HLA-Matched Allogeneic Bone Marrow Transplantation with Posttransplant Cyclophosphamide

Background We previously demonstrated comparable immune reconstitution after HLA-matched sibling (MSD), HLA-matched unrelated (MUD), and HLA-haploidentical (haplo) bone marrow transplantation (BMT) with posttransplant cyclophosphamide (PTCy). Here, we use machine learning algorithms to identify predictive immunologic variables, providing insight for future translational interventions. Methods We assessed 11 pre-transplant factors, 22 immune subsets, and 7 serum markers at day 28 and day 56 post-BMT in 70 patients who engrafted after myeloablative conditioned (MAC) haplo BMT with PTCy (50mg/kg on days +3 and +4), mycophenolate mofetil (days +5-35), and tacrolimus (days +5-180) and 74 patients who engrafted after MAC HLA-matched BMT with PTCy (50mg/kg on days +3 and +4). Classification and regression tree machine based learning with nodal selection was applied to detect risk groups for four outcomes: overall survival (OS), progression-free survival (PFS), acute graft-versus-host disease (aGVHD), and chronic graft-versus-host disease (cGVHD). Results When compared with cytomegalovirus (CMV) seronegative recipients, CMV seropositive recipients had higher CD3+ T cells, effector memory (EM) CD4+ T cells, T effector memory expressing RA (TEMRA) CD4+ T cells, CD8+ T cells, EM CD8+ T cells, and TEMRA CD8+ T cells at early time points after both BMT platforms (not shown). Pre-BMT disease status and natural killer (NK) cell count at day 28 emerged as predictive variables for survival. Two-year OS and PFS for patients in complete remission (CR) with NK cells >54 cells/µL were 98% and 89%, in CR with NK cells 55 cells/µL, the CuI of aGVHD was 18% in those with CXCL-9 Conclusion Machine learning using immune cellular and soluble markers can be successfully applied to identify risk factors for BMT outcomes. High CD4+ counts and CXCL-9 levels at day 28 predicted aGVHD and high reg3α at day 56 predicted cGVHD. Both CXCL-9 and reg3α represent potential therapeutic targets. Finally, disease status and NK cell counts at day 28 predicted OS and PFS. These data support research to determine what influences NK cell recovery as well as to investigate NK cell therapy for recipients with active disease or for those with poor early NK cell reconstitution.

Allogeneic hematopoietic stem cell transplantation using posttransplant cyclophosphamide

Posttransplant cyclophosphamide (PTCy) was initially developed by the Johns Hopkins group as a graft-versus-host disease (GVHD) prophylaxis for human leukocyte antigen (HLA)-haploidentical stem cell transplantation. Recently, PTCy has been attempted in HLA-matched transplantation. In HLA-haploidentical hematopoietic transplantation, several retrospective studies have compared HLA-matched transplantation with HLA-haploidentical hematopoietic transplantation using PTCy. In these reports, transplantation outcomes have been comparable. Therefore, PTCy- based haploidentical transplantation is a viable alternative to HLA-matched transplantation. Moreover, In HLA-matched transplantation, PTCy alone may be sufficient in the prevention of GVHD in HLA-matched bone marrow transplantation. Although PTCy alone is not enough in HLA-matched peripheral blood stem cell transplantation, PTCy has demonstrated excellent GVHD inhibition when combined with several immunosuppressive agents, such as calcineurin inhibitor and mycophenolate mofetil. Furthermore, PTCy also playing a significant role in other areas, such as aplastic anemia, salvage transplantation for graft failure, and allogeneic transplantation after checkpoint inhibitor use. PTCy can be performed inexpensively and without any special equipment or techniques at any institution. It is expected that PTCy will continue to spread worldwide in the future.

Choice of conditioning regimens for bone marrow transplantation in severe aplastic anemia

AbstractAllogeneic bone marrow transplantation (BMT) is curative therapy for the treatment of patients with severe aplastic anemia (SAA). However, several conditioning regimens can be used for BMT. We evaluated transplant conditioning regimens for BMT in SAA after HLA-matched sibling and unrelated donor BMT. For recipients of HLA-matched sibling donor transplantation (n = 955), fludarabine (Flu)/cyclophosphamide (Cy)/antithymocyte globulin (ATG) or Cy/ATG led to the best survival. The 5-year probabilities of survival with Flu/Cy/ATG, Cy/ATG, Cy ± Flu, and busulfan/Cy were 91%, 91%, 80%, and 84%, respectively (P = .001). For recipients of 8/8 and 7/8 HLA allele-matched unrelated donor transplantation (n = 409), there were no differences in survival between regimens. The 5-year probabilities of survival with Cy/ATG/total body irradiation 200 cGy, Flu/Cy/ATG/total body irradiation 200 cGy, Flu/Cy/ATG, and Cy/ATG were 77%, 80%, 75%, and 72%, respectively (P = .61). Rabbit-derived ATG compared with equine-derived ATG was associated with a lower risk of grade II to IV acute graft-versus-host disease (GVHD) (hazard ratio [HR], 0.39; P < .001) but not chronic GVHD. Independent of conditioning regimen, survival was lower in patients aged >30 years after HLA-matched sibling (HR, 2.74; P < .001) or unrelated donor (HR, 1.98; P = .001) transplantation. These data support Flu/Cy/ATG and Cy/ATG as optimal regimens for HLA-matched sibling BMT. Although survival after an unrelated donor BMT did not differ between regimens, use of rabbit-derived ATG may be preferred because of lower risks of acute GVHD.

Development of Grade II Acute Graft-versus-Host Disease Is Associated with Improved Survival after Myeloablative HLA-Matched Bone Marrow Transplantation using Single-Agent Post-Transplant Cyclophosphamide.

Post-transplant cyclophosphamide (PTCy) can be used as the sole immunosuppression after myeloablative conditioning (MAC) for HLA-matched bone marrow transplantation (BMT). However, the effects of graft-versus-host disease (GVHD) with this platform are undefined. We retrospectively analyzed 298 consecutive adult patients with hematologic malignancies who engrafted after MAC HLA-matched sibling donor (MSD; n = 187) or HLA-matched unrelated donor (MUD; n = 111) T-cell-replete BMT with PTCy 50 mg/kg on days +3 and +4. After MSD and MUD BMT, 35% and 57% of patients, respectively, developed grade II acute GVHD (aGVHD) by 100 days, 11% and 14% grade III to IV aGVHD by 100 days, and 9% and 16% chronic GVHD (cGVHD) by 1 year. In landmark analyses at 100 days after HLA-matched BMT, 4-year overall survival (OS) and progression-free survival (PFS) were 57% (95% confidence interval [CI], .49 to .67) and 40% (95% CI, .31 to .51) in patients without grades II to IV aGVHD, and 68% (95% CI, .59 to .78) and 54% (95% CI, .44 to .65) in patients with grade II aGVHD. In adjusted time-dependent multivariable analyses, grade II aGVHD was associated with improved OS (hazard ratio, .58; 95% CI, .37 to .89; P = .01) and PFS (hazard ratio, .50; 95% CI, .34 to .74; P < .001) after HLA-matched BMT with PTCy. The ability of PTCy to limit grades III to IV aGVHD and cGVHD while maintaining grade II aGVHD may contribute to its effectiveness, and further attempts to reduce aGVHD may be detrimental.

Early Fever after Haploidentical Bone Marrow Transplantation Correlates with Class II HLA-Mismatching and Myeloablation but Not Outcomes

Noninfectious fevers are common early after T cell–replete HLA haploidentical (haplo) peripheral blood transplants and have been associated with cytokine release syndrome and overall mortality. However, less is known regarding the incidence and associations of early fever after bone marrow transplantation (BMT) with post-transplant cyclophosphamide (PTCy). We hypothesized that early fever would be associated with myeloablative conditioning (MAC), because of its relative increase in tissue damage augmenting antigen presentation and class II HLA-mismatching because of recognition of antigen-presenting cells by CD4+ T cells. In 672 recipients of MAC HLA-matched related donor (MRD) (n = 183), MAC HLA-matched unrelated donor (MUD) (n = 115), MAC haplo (n = 79), or nonmyeloablative (NMA) haplo (n = 295) T cell–replete BMT with PTCy, we retrospectively analyzed early noninfectious fever defined as temperature of ≥38.3°C once or ≥38.0°C twice or more on days 1 to 6. Fever occurred in 13% after MAC MRD, 23% after MAC MUD, 44% after NMA haplo, and 84% after MAC haplo BMT (P < .0001). Survival outcomes did not differ between patients with and without early fever. In NMA haplo BMT, mismatch in the graft-versus-host direction at HLA-DRB1 or -DPB1 (but not HLA-A, -B, -Cw, or -DQB1) was associated with early fever compared with no mismatches at these loci (P < .0001 and P = .02, respectively). In multivariable modeling, -DRB1 or -DPB1 mismatch and higher CD3+ graft cell dose were significantly associated with early fever. Early fever is more common after haplo compared with HLA-matched BMT. Fever is associated with myeloablation, -DRB1 or -DPB1 mismatching, and higher CD3+ graft cell dose but not survival.

Post-Transplant Cyclophosphamide as Sole Graft-versus-Host Disease Prophylaxis Is Feasible in Patients Undergoing Peripheral Blood Stem Cell Transplantation for Severe Aplastic Anemia Using Matched Sibling Donors

High-dose cyclophosphamide (PTCY) after allogeneic hematopoietic cell transplantation (HSCT) has been shown to be effective in preventing graft-versus-host disease (GVHD) after HLA-matched bone marrow transplantation. We performed a phase II study of PTCY given at 50 mg/kg i.v. on days 3 and 4 as the sole GVHD prophylaxis after HSCT for severe aplastic anemia (SAA) in patients receiving granulocyte colony-stimulating factor–mobilized peripheral blood stem cell (PBSC) grafts from HLA-matched related donors after conditioning with fludarabine, CY, and single-dose total body irradiation. Thirty patients with a median age of 29 years (range, 16 to 49) were enrolled in this study. Engraftment was seen in 27 patients (90%) at a median of 16 days (range, 12 to 21) post-HSCT. None of the patients developed veno-occlusive disease of the liver or hemorrhagic cystitis. Grades II to IV acute GVHD was seen in 22% of patients with grades III to IV GVHD in 11.1%. The 2-year cumulative incidence of chronic GVHD was 22.7%. Fourteen patients (46.6%) did not require any further immunosuppression after receiving PTCY. Comparing with 2 historical cohorts of 30 patients each who received cyclosporine and methotrexate (MTX; at 15 mg/m2 [MTX15] and 10 mg/m2 [MTX10]), the incidence of grades II to IV acute GVHD was lower, albeit not significantly, with the use of PTCY (PTCY, 22.2%, vs MTX15, 37.1%, vs MTX10, 53.8%; P = .056), whereas rates of chronic GVHD were significantly reduced (PTCY, 22.7%, vs MTX15, 63.6%, vs MTX10, 76.2%; P = .013). Viral infections including cytomegalovirus were significantly higher with the use of PTCY (60%) compared with cyclosporine and MTX (MTX15, 23.3%, vs MTX10, 33.3%; P = .008). Overall survival was similar between the 3 groups. We conclude that PTCY as the sole GVHD prophylaxis is associated with low rates of acute and chronic GVHD in patients undergoing PBSC transplant for SAA using HLA-matched donors. This trial is registered at CTRI/2010/091/001480.

Grade II Acute Graft-versus-Host Disease and Higher Nucleated Cell Graft Dose Improve Progression-Free Survival after HLA-Haploidentical Transplant with Post-Transplant Cyclophosphamide

Compared with standard graft-versus-host disease (GVHD) prophylaxis platforms, post-transplantation cyclophosphamide (PTCy) after T cell–replete HLA-haploidentical (haplo) bone marrow transplantation (BMT) reduces the risk of grades III to IV acute (a) and chronic (c) GVHD, but maintains similar rates of grade II aGVHD. Given that mild GVHD has been associated with reduced treatment failure in HLA-matched BMT, we evaluated the risk factors for and effects of GVHD on survival in 340 adults with hematologic malignancies who engrafted after nonmyeloablative haplo-BMT with PTCy, mycophenolate mofetil, and tacrolimus. The cumulative incidence at 100 days of grade II and grades III to IV aGVHD were 30% (95% confidence interval [CI], 25% to 35%) and 2% (95% CI, 1% to 4%), respectively. The 1-year cumulative incidence of cGVHD was 10% (95% CI, 7% to 13%). In landmark analyses at 100 days, the 4-year probabilities of overall survival (OS) and progression-free survival (PFS) were, 48% (95% CI, 41% to 56%) and 39% (95% CI, 32% to 47%) for patients without grades II to IV aGVHD, compared with 63% (95% CI, 53% to 73%) and 59% (95% CI, 50% to 71%) for patients with grade II aGVHD (P = .05 and P = .009). In multivariable modeling, when compared with patients who never experienced GVHD, the hazard ratio (HR) for OS and PFS in patients with grade II aGVHD was .78 (95% CI, .54 to 1.13; P = .19) and .69 (95% CI, .48 to .98; P = .04). Higher nucleated cell graft dose was also associated with improved OS (HR, .88; 95% CI, .78 to 1.00; P = .05) and PFS (HR, .89; 95% CI, .79 to 1.0; P = .05) and decreased risk of grades III to IV aGVHD (subdistribution HR, .66; 95% CI, .46 to .96; P = .03). PTCy reduces grades III to IV aGVHD and cGVHD, but retains similar incidence of grade II aGVHD, the development of which improves PFS. Higher nucleated cell graft dose goals may also improve survival after nonmyeloablative haplo-BMT with PTCy.

The recipient CCR5 variation predicts survival outcomes after bone marrow transplantation

The chemokine receptor CCR5 plays roles in the trafficking of effector cells towards the site of inflammation. We retrospectively examined the impact of the CCR5 variation (rs1800023, -2086A>G) on transplant outcomes in a cohort of 329 patients who underwent unrelated HLA-matched bone marrow transplantation (BMT) for hematologic malignancies through the Japan Marrow Donor Program. A multivariate analysis showed that the recipient CCR5 -2086A/A genotype was significantly associated with a lower relapse rate but not with the development of graft-versus-host disease (GVHD) or transplant-related mortality, thereby resulting in better disease-free and overall survival rates than other variations. The donor CCR5 -2086A/A genotype was associated with a lower incidence of grades 3–4 acute GVHD, which did not improve the survival outcomes. These findings suggest that the recipient CCR5 -2086A/A genotype affects the induction of the graft-versus-tumor effect without augmenting the development of GVHD. CCR5 genotyping in transplant recipients may therefore be a useful tool for evaluating pretransplantation risks.

Toll-like receptor genetic variations in bone marrow transplantation.

The Toll-like receptor family mediates the innate immune system through recognizing the molecular patterns of microorganisms and self-components and leading the synthesis of the inflammatory mediators. We retrospectively examined whether or not genetic variations in toll-like receptor 1 (rs5743551, -7202GQ>A), toll-like receptor 2 (rs7656411, 22215G>T), and toll-like receptor 4 (rs11536889, +3725G>C) affected transplant outcomes in a cohort of 365 patients who underwent unrelated HLA-matched bone marrow transplantation (for hematologic malignancies through the Japan Marrow Donor Program. Only donor toll-like receptor 4 variation significantly improved the survival outcomes. A multivariate analysis showed that the donor toll-like receptor 4 +3725G/G genotype was significantly associated with a better 5-year progression-free survival and a lower 5-year transplant-related mortality than other variations. Furthermore, the donor toll-like receptor 4 +3725G/G genotype was associated with a significantly lower incidence of fatal infections than other variations. The validation study of 502 patients confirmed that the donor toll-like receptor 4 +3725G/G genotype was associated with better survival outcomes. Toll-like receptor4 genotyping in transplant donors may therefore be a useful tool for optimizing donor selection and evaluating pretransplantation risks.

ALDH2 Polymorphism Has a Significant Impact on Transplant Related Mortality after HLA-Matched Bone Marrow Transplantation

Background:Aldehyde dehydrogenase 2 (ALDH2), a mitochondrial enzyme known to degrade acetaldehyde metabolized from ethanol, is also involved in critically important biological processes such as drug metabolism and DNA repair in hematopoietic stem cells. Based on its role in these biological processes, we hypothesized that a functional ALDH2Glu504Lys polymorphism, which is highly prevalent in East Asian populations, could affect the outcome of hematopoietic transplant recipients. Here, we investigated the association between recipient and donor ALDH2 polymorphism and the clinical outcomes of bone marrow transplantation (BMT).Methods.:We analyzed the Japanese national registry data for 409 patients who underwent allogeneic BMT from an HLA-matched unrelated donor through the Japan Marrow Donor Program. The probability of overall survival (OS) was estimated according to the Kaplan-Meier method. The probabilities of relapse, transplant-related mortality (TRM), engraftment, and graft-versus-host disease (GVHD) were estimated based on cumulative incidence curves. Competing events were death without relapse for relapse, relapse for TRM, death without engraftment for engraftment, and death without GVHD for GVHD. To evaluate the impact of recipient and donor ALDH2 polymorphism on transplant outcomes, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) after adjusting for potential confounders. The Cox proportional hazards model was used to evaluate the effect on OS, whereas Fine and Gray's proportional hazards model was used for the other endpoints.Results.:The median follow-up period in survivors was 6.3 years (range, 0.3-13.1 years). The unadjusted 3-year OS rate was 51% (95% CI, 43%-57%) in Glu/Glu genotype recipients, 52% (43%-60%) in Glu/Lys genotype recipients, and 43% (25%-60%) in Lys/Lys genotype recipients. We did not observe a statistically significant association between the recipient ALDH2 polymorphism and OS. The cumulative incidence of unadjusted 3-year TRM was 28% (21%-34%) in Glu/Glu genotype recipients, 25% (18%-33%) in Glu/Lys genotype recipients, and 50% (29%-68%) in Lys/Lys genotype recipients. The recipient ALDH2 Lys/Lys genotype was significantly associated with a higher TRM, with a HR relative to Glu/Glu genotype of 2.45 (95% CI = 1.22-4.90, P = 0.01). Among the causes of TRM, the incidence rate of organ failure in recipients with the Lys/Lys genotype was twice as high as in recipients with the Glu/Glu genotype (5.9 vs. 3.0 per 1,000 person-days). A statistically significant association between the recipient ALDH2 polymorphism and relapse or GVHD was not observed. With regard to engraftment, the cumulative incidence of platelet engraftment at day 50 was 82% (76%-87%) in Glu/Glu genotype recipients, 80% (72%-85%) in Glu/Lys genotype recipients, and 65% (47%-78%) in Lys/Lys genotype recipients. Compared to the recipient Glu/Glu genotype, the recipient Lys/Lys genotype was marginally significantly associated with delayed platelet engraftment (HR = 0.60, 95% CI = 0.43-1.03, P = 0.06). In contrast, donor ALDH2 polymorphism did not show any significant association with transplant outcomes.Conclusions:We observed poor TRM and delayed platelet engraftment in HLA-matched unrelated BMT recipients with ALDH2 Lys/Lys genotype. Taken functional significance of this polymorphism, our results might indicate that recipient ALDH2 polymorphism could affect the metabolism of chemotherapeutic agents leading to higher TRM and delayed platelet engraftment. DisclosuresNo relevant conflicts of interest to declare.

Toll-like receptor 1 variation increases the risk of transplant-related mortality in hematologic malignancies

Toll-like receptor 1 (TLR1) genetic variant (rs5743551, −7202A>G) has been reported to be associated with susceptibility to various infectious diseases. We retrospectively examined the impact of TLR1 variation on transplant outcomes in a cohort of 320 patients who underwent unrelated HLA-matched bone marrow transplantation (BMT) for hematologic malignancies. A multivariate analysis showed that the G/G genotype in the recipients and the donors was associated with a significantly lower 3-year transplant-related mortality (TRM). The recipient G/G genotype also resulted in a better 3-year progression-free survival. This study suggests that the recipient and donor TLR1 G/G genotypes are comparably associated with a reduced risk of death that was not related to relapse. Thus, TLR1 genotyping may be useful for selecting the donor, managing patients in a risk-adapted manner, and creating therapeutic strategies to prevent complications after hematopoietic stem cell transplantation.

Optimal Outcomes in Young Class 3 Patients With Thalassemia Undergoing HLA-Identical Sibling Bone Marrow Transplantation.

Bone marrow transplantation (BMT) for class 3 patients with thalassemia is challenging due to high rates of graft rejection and transplant-related mortality. Since the first studies of BMT in the late 1980s, a number of conditioning regimens have been designed to improve outcomes, but with suboptimal results. Here we report the outcome of transplantation in class 3 patients using a modified protocol. Sixty-three patients between 5 and 16.7 years of age with class 3 thalassemia received HLA-matched sibling BMT following either the original protocol (26 patients) or the modified protocol (37 patients). Both regimens comprised preconditioning cytoreduction with hydroxyurea and azathioprine starting at -45 days pretransplant, and fludarabine from days -16 to -12. Conditioning was performed with busulfan and cyclophosphamide (original protocol) or with busulfan, thiotepa, and cyclophosphamide (modified protocol). The 2 groups showed similar patient demographics. At day 0, the degree of cytoreduction (lymphopenia, neuthropenia, and thrombocytopenia) achieved by the modified protocol was greater than the original protocol. The incidence of graft failure/rejection was significantly higher in the original group (15%; 95% confidence interval [95% CI], 5-32%) compared with the modified group (0%) (P = 0.014). The respective 5-year thalassemia-free survival rates were 73% (95% CI, 51-86%) and 92% (95% CI, 77-97%) (P = 0.047). Both groups showed similar incidences of grades II to IV acute graft-versus host disease. Modified protocol did not increase nonhematological toxicity or infectious complications. The modified treatment protocol effectively and safely prevented graft failure/rejection and significantly increased thalassemia-free survival of class 3 patients with thalassemia.

447. Lentiviral Gene Therapy in a Preclinical Model of Omenn Syndrome

Patients with Omenn syndrome (OS), carrying hypomorphic recombination activating genes (RAG) mutations, develop a peculiar severe combined immunodeficiency associated with autoimmune-like manifestations. RAG1 and RAG2 genes play an essential role in the generation of antigen receptors during lymphocyte development. HLA-matched bone marrow transplantation is curative, however, hematopoietic stem cell gene therapy (GT) could represent an alternative treatment for patients lacking a suitable donor. The aim of the present study was to investigate the efficacy of GT in a knock-in murine model carrying the Rag2 R229Q mutation that mimics most of the symptoms of human OS. To this aim, we are testing a lentiviral vector encoding for codon optimized human RAG2 (hRAG2co-LV vector) under the control of the ubiquitous chromatin opening element (UCOE).We initially measured the efficiency of transduction of Rag2R229Q/R229Q lineage negative (lin-) cells by testing the presence of the integrated viral vector by real-time PCR in lin- cells transduced at a multiplicity of infection (MOI) 5 and 10 and in vitro cultured for 8 days. We observed that the hRAG2co-LV vector transduced Rag2R229Q/R229Q lin- cells very efficiently at MOI 5. Then, we tested the in vivo efficacy of hRAG2co-LV-mediated GT infusing transduced lin- BM cells isolated from male Rag2R229Q/R229Q mice in lethally irradiated females. Control Rag2R229Q/R229Q mice received wild-type (BMT-WT) or untransduced (BMT-OS) lin- BM cells. Analysis of immune cells in peripheral blood was evaluated overtime starting from six weeks after the treatment. GT-treated mice showed the appearance and progressive increase of B cells and amelioration of T cell frequency and absolute count as compared to BMT-OS mice. In parallel, the frequency of myeloid cells started to decrease 13 weeks after GT indicating a normalization of peripheral immune cell distribution. Our preliminary data demonstrate the feasibility of GT in the preclinical model of OS. Additional experiments aimed at evaluating long-term efficacy and safety are ongoing.