Cases Of cGVHD Research Articles

Different Sources of Hematopoietic Stem Cell Transplantation in Patients with Thalassemia Major: Relationship between Immune Reconstitution, Graft-Versus-Host Disease, and Viral Infections

Objective: To compare the relationship among immune reconstitution, graft-versus-host disease (GVHD), and viral infections in three kinds of hematopoietic stem cell transplantation(HSCT) using different host sources for thalassemia major(TM) patients: matched unrelated donor (MUD) HSCT, haploidentical (Haplo) HSCT with post-transplant cyclophosphamide (PTCy)-based prophylactic therapy, and TCRαβ-T cell-depleted HSCT (TDH). Methods: A total of 191 TM patients in our center between October 2018 and June 2022 were included in this study, comprising three transplant groups: MUD group (n=56), PTCy group (n=45), and TDH group (n=90). Four-color flow cytometry was used to detect the proportions and absolute counts of lymphocyte subsets at the 12th month after transplantation for the three different donor types. The immune reconstitution was analyzed and compared with the occurrence of GVHD and virus infections. Results: 1. Immune Reconstitution: (1) The ratio of helper cells (CD3 +CD4 +)/cytotoxic T cells (CD3 +CD8 +) at the 12 months after transplantation was compared among the three groups. There were statistically significant differences between the TDH and PTCy groups, as well as between the TDH and MUD groups(P=022 and 0.011, respectively). No statistical difference was found between the PTCy and MUD groups (P=0.932). The CD4 +/CD8 + ratio in the TDH group recovered the fastest and had already returned to the normal reference range (0.7-2.7). (2) The comparison of B cells (CD3 -CD19 +) at the 12 months after transplantation showed statistically significant differences between the TDH and PTCy groups, as well as between the MUD and PTCy groups (P=0.049 and 0.034, respectively). No statistical difference was found between the TDH and MUD groups (P=0.447). The recovery of B cells was faster in the TDH and MUD groups, while it was slowest in the PTCy group. (3) The comparison of natural killer cells (NK cells) (CD3 -CD56 +) at the 12 months after transplantation showed statistically significant differences between the TDH and PTCy groups, as well as between the TDH and MUD groups (P=0.048 and 0.000, respectively). No statistical difference was found between the PTCy and MUD groups (P=0.366). The TDH group exhibited the fastest recovery of NK cells. 2. Chronic GVHD (cGVHD): (1) 7/90 cases (7.78%) of cGVHD appeared in the TDH group, 19/45 cases (42.22%) in the PTCy group, and 2/56 cases (3.57%) n the MUD group. (2) No statistical difference showed in the incidence of cGVHD between the TDH and MUD groups (P=0.500). There was a statistical difference in the incidence of cGVHD between the TDH and PTCy groups (P=0.000), as well as between the MUD and PTCy groups (P=0.000). 3. Viral Infection: (1) 22/90 cases (24.44%) of viral infection occurred in the TDH group, 7/45 cases (15.56%) in the PTCy group, and 6/56 cases (10.71%) in the MUD group. (2) Among the 90 cases of TDH group, the CD4/CD8 ratio at the 6 months after transplantation was 0.41±0.24 in the 22 cases with viral infection and 0.69±0.40 in the 68 cases without that. There was a statistical difference in the mean CD4/CD8 ratio between the two divisions in the TDH group (P=0.013). Conclusion:The TDH group exhibited faster immune reconstitution compared to the other two groups, especially in terms of CD4/CD8 ratio, B cells, and NK cells. This may be related to two special factors for patients underwent TDH in our center: a rather high average infusion of CD34 cells (30×10 6/kg) , and the preservation of γδ cells, B cells, and NK cells with the removing of TCRαβ-T cells in the TDH treatment protocol. The TDH and MUD groups showed a lower incidence of cGVHD, while the PTCy group had a higher incidence. The occurrence of viral infection in the TDH group was 24.44%. Also, the lower a CD4/CD8 ratio at the 6 months after transplantation, the higher the incidence of viral infection. Table 1. The Absolute Counts of Lymphocyte Subsets at the 12th Month after Transplantation

Real-World Outcomes of Pfts in Screening for Lung Involvement in Chronic Gvhd Post-Allogeneic Stem Cell Transplant: A Retrospective Study of 387 Patients in British Columbia, Canada

Introduction: Lung involvement in chronic graft versus host disease (cGVHD) is an uncommon but potentially devastating complication with significant morbidity and mortality in patients who have received an allogeneic hematopoietic stem cell transplant (alloHSCT). Unfortunately, early detection remains difficult as early lung cGVHD tends to be asymptomatic or present with nonspecific symptoms such as cough or mild shortness of breath. In British Columbia (BC), Canada, routine pulmonary function tests (PFTs) have been employed in the screening of lung cGVHD in this population at an interval of every 3-4 months for the first 2-3 years after alloHSCT. However, it is unknown whether routine screening 1) improves detection of lung cGVHD, and 2) enables earlier intervention to lead to better outcomes. We aimed to assess the real-world outcomes of lung cGVHD screening and compared the characteristics and clinical results of patients who had lung cGVHD detected via routine PFT screening, versus those who were detected after development of symptoms. Methods: A retrospective chart review was conducted on all adult patients who underwent an alloHSCT at BC, Canada between June 2017 and January 2021. Patients were followed until August 2022. Patients were excluded if they had primary graft failure or if they died within 100 days after transplant. All types of pulmonary GVHD were included analysis and cases were established by the treating clinician in the clinical record. NIH consensus criteria were used to grade cGVHD severity. Statistical significance was calculated using the Chi square test for categorical variables and T-test for continuous variables. Results: Among 387 eligible consecutive patients who underwent alloHSCT, 189 (49%) developed cGVHD, with 33 (9%) cases of lung involvement. The mean time to diagnosis of lung cGVHD from the date of transplant was 13 ± 8 months. There were 16 cases of lung cGVHD (48%) that were initially detected by routine screening, while 17 cases (52%) were first detected due to clinical symptoms that developed in between screening visits or after the screening period ended (two patients developed symptoms at 27 months and 43 months respectively). Patient characteristics are presented on Table 1. Lung involvement was the first cGHVD sign in 17/33 (51%) of patients, with 5 (15%) detected by routine screening and 12 (36%) due to symptoms. At time of diagnosis of lung involvement, 12/33 (36%) of patients were already on systemic immunosuppression for cGVHD with 9 (56%) of these cases detected from screening and 3 (18%) from symptoms (p=0.02). All patients had a maximum overall cGVHD severity by NIH criteria of 2-3. Sixteen of 33 (48%) patients had a lung cGVHD score by NIH criteria of 2-3 at diagnosis, with a mean FEV1 of 54% ± 15, compared to 17 (52%) patients with a score of 1 and mean FEV1 of 78% ± 12. The NIH score at diagnosis was not significantly different between those picked up by routine screening versus symptoms (p=0.76). Eighteen of 33 (55%) patients had a maximum lung cGVHD score by NIH criteria of 2-3, with the mean lowest FEV1 of 52% ± 15, compared to 15 patients (45%) with a maximum lung cGVHD score of 1, with the mean lowest FEV1 of 77% ± 10. Similarly, the maximum NIH lung cGVHD score were not significantly different between those picked up by routine screening versus symptoms (p=0.08). However, patients picked up on screening were more likely to have significant clinical improvements in lung function (4/16 [25%] versus 0/17 [0%], p=0.03), and less likely to die from lung cGVHD (0/16 [0%] versus 5/17 [29%], p=0.02). Conclusions: Routine screening PFTs are effective for early diagnosis of asymptomatic lung cGVHD, and are associated with improved outcomes compared to patients who were diagnosed after symptoms developed. Since a significant number of these patients were not previously receiving immunosuppression for other cGVHD, this suggests a potential benefit in screening all patients every 3 months, regardless of prior GVHD status.

The Impact of Post-Transplant Cyclophosphamide (PTCy) with or without MMF in the Prevention of De Novo and Progressive / Relapsing Chronic Graft-Versus-Host Disease after HLA-Matched Donor Transplant

Background: We previously showed that PTCy/Tac ± MMF is associated with a significant reduction in the rate of chronic graft-versus-host disease (cGvHD) as compared to Tac/MTX after HLA-matched sibling (MSD) but not after HLA-matched unrelated (MUD) donor stem cell transplant (SCT). Notably, ATG was used with Tac/MTX in MUD but not in MSD. [ Transplant Cell Ther. 2022;28(10):695] We aimed to further elucidate the epidemiology of cGvHD with the use of PTCy/Tac by comparing the impact of Tac/MTX vs PTCy/Tac ± MMF on de novo and progressive/relapsing cGvHD. Methods: Recipients of a MSD (Tac/MTX no ATG, or PTCy-based) or MUD (Tac/MTX with ATG, or PTCy-based) peripheral blood SCT between 2015-21 at our institution were eligible. To evaluate the impact of prophylaxis on the incidence of de novo and progressive/relapsing cGvHD, we performed two separate landmark analyses starting 3 months (mo) post-SCT among patients who had not and those who had been diagnosed with acute GvHD (aGvHD) within 3 mo post-SCT, respectively. Patients who died or experienced relapse of malignancy (n=135) or were diagnosed with cGvHD within 3 mo post-SCT (n=13) were excluded from the landmark analyses. There was no difference in the rate of early death/relapse or cGvHD by prophylaxis. Results: 1040 patients met the eligibility criteria. Median follow-up in survivors was 28 mo (IQRT: 18, 50). The cumulative incidence (CumInc) of cGvHD in the Tac/MTX, PTCy/Tac without MMF, and PTC/Tac with MMF groups was 39% (34-45, reference), 20% (14-29, p<0.001) and 20% (13-30, p=0.003) respectively in MSD; and 23% (18-30, reference), 17% (12-26; p=0.2), and 19% (14-26; p=0.6) respectively in MUD. Consistent with our previous findings, within the PTCy/Tac group, MMF was not associated with the overall rate of cGvHD in MSD (HR=1.2, 95% CI 0.6-2.1, p=0.6) or MUD (HR=1.3, 95% CI 0.7-2.2, p=0.4). However, in the current study, stratified analyses performed to evaluate the impact of prophylaxis on the risk of de novo vs progressive/relapsing cGvHD revealed a potential role for MMF in the development of de novo cGvHD. Subsequent results are presented separately for the de novo and progressive/relapsing cGvHD risk cohorts (Table). The de novo cGvHD risk cohort included patients (N=442) who had not been diagnosed with aGvHD within 3 mo post-SCT. AML / MDS (60%) and CML / MPD (16%) were the most common diagnoses. 124 cases of cGvHD were diagnosed 3 -36 mo post-SCT with a CumInc of32% (27-37). In multivariate analysis (MVA), compared to Tac/MTX, the use of PTCy/Tac without MMF (HR=0.3, 95% CI 0.2-0.6, p<0.001) was associated with a significant reduction in the incidence of cGvHD. Such reduction was not observed (Figure) with PTCy/Tac with MMF (HR vs Tac/MTX=1.0, 95% CI 0.6-1.5, p=0.9). Additional independent predictors were myeloablative conditioning (HR=1.9, 95% CI 1.3-2.9, p=0.001) and MSD (HR=1.5, 95% CI 1.2-2.6, p=0.003). Notably, progression-free survival (PFS) was similar in PTCy/Tac/MMF (univariate HR: 0.8, 95% CI 0.5-1.4, p=0.4) vs PTCy/Tac. The progressive/relapsing cGvHD risk cohort included patients (N=450) who had been diagnosed with grade 1 (27%), 2 (59%) or 3-4 (14%) aGvHD within 3 mo post-SCT. AML / MDS (64%) and CML / MPD (14%) were the most common diagnoses. 109 cases of cGvHD were diagnosed 3 -36 mo post-SCT with a CumInc of 28% (24-33). In MVA analysis, the impact of prophylaxis differed by donor type. As compared with Tac/MTX, PTCy/Tac ± MMF was associated with significantly lower rate of progressive/relapsing cGVHD in MSD (HR=0.2, 95% CI 0.1-0.4, p<0.001) but not in MUD (HR=0.6, 95% CI 0.4-1.1, p=0.09). This may be related to the use of ATG with Tac/MTX in MUD which was not used in MSD. HCT-CI ≥3 was the only other significant predictor of cGvHD (HR=0.6, 0.4-0.9, p=0.03). PFS was similar in PTCy/Tac ± MMF vs Tac/MTX in MSD (univariate HR: 0.8, 95% CI 0.5-1.3, p=0.3) or MUD (univariate HR: 0.8, 95% CI 0.5-1.2, p=0.3). Conclusions: PTCy/Tac ± MMF prophylaxis slows the development of progressive/relapsing cGvHD in MSD vs (Tac/MTX no ATG), but not in MUD (vs Tac/MTX with ATG). The addition of MMF to PTCy/Tac (vs PTCy/Tac) has no significant impact on the risk of progressive/relapsing cGVHD in MSD or MUD; but is associated with a higher risk of de novo cGvHD in MSD and MUD. Our data suggest that multi-center studies are warranted to determine whether MMF should be excluded from cGvHD prevention regimens in the HLA-matched donor setting with PTCy- based GvHD prophylaxis.

Combining Low-Dose Post-Transplant Cyclophosphamide(PTCY) with Anti-Thymocyte Globulin(ATG) for Prophylaxis of Graft-Versus-Host Disease in Alternative-Donor Hematopoietic Stem Cell Transplantation for β-Thalassemia Major

Background ： The 5-year overall survival rate (OS) for children with thalassemia major who undergo allogeneic stem cell transplantation is 90% and the event-free survival (EFS) rate is 86%. Due to the limited availability of matched sibling donors, the proportion of transplantations from alternative donors is increasing, particularly from haplo-identical donors. Post-transplant infections and graft-versus-host disease (GVHD) remain the major causes of mortality, especially in those who receive transplantation from alternative donors. Post-transplant cyclophosphamide (PTCY) has shown outstanding results of GVHD prophylaxis in haploidentical matched related donors transplantation with hematological malignancies. However, there is insufficient clinical evidence for its application in pediatric patients who received transplantation from haplo-identical donors with non-malignant hematological disease. Here, we retrospectively analyzed the results of 40 cases that underwent allogeneic stem cell transplantation from haploidentical matched related donors (Haplo-RD) and unrelated donors (UD) to evaluate the safety and efficacy of the novel regimen in GVHD prophylaxis. Method A total of 40 patients with β-thalassemia major received stem cell transplantation, 10 haploid donors (Group Haplo-RD), and 30 unrelated donors (Group UD). Among Group UD, 15 donors were 1 or 2 HLA locus mismatched, remaining 15 were identically matched. The median age of the patients was 5.5 years, ranging from 2 to 12. The Conditioning regimen mainly consisted of fludarabine, busulfan, cyclophosphamide, and thiotepa. GVHD prophylaxis included ATG 1.5mg/kg×3d, cyclophosphamide (CTX) 25mg/kg×2d, cyclosporin A (CsA), and mycophenolate mofetil (MMF). We analyzed the engraftment rate, GVHD incidence, survival rate, and virus reactivation rate for each group. Results Engraftment rate was 100%, with a median time of 11 (10-15) days for neutrophil implantation and 12 (6-31) days for platelet implantation. All patients achieved complete chimerism on day 30 after transplantation. Three cases (7.5%) suffered from Ⅲ-Ⅳ aGVHD, with one being in the Group Haplo-RD group and two in the Group UD. Four cases (10.0%) of cGVHD were recorded. The overall survival (OS) rate and thalassemia-free survival rate were both 92.5%. In Group Haplo-RD, both the OS and thalassemia-free survival rates were 100%. Eight cases reported cytomegaloviremia but no one developed to CMV disease. The total activation rate for CMV was 20%. Nine cases suffered from BK virus urinary tract infection, resulting in a total activation rate of 22.5%. Detailed results are shown in Table 1 and Figure 1. Discussion Due to the high risk of GVHD and infection, stem cell transplantation from haploidentical and unrelated donors cannot be routine therapy for children with thalassemia major. Standard-dose PTCY regimen significantly increases the risk of CMV and BK infection after transplantation and is not suitable for non-malignant disease. The results have been reported that low-dose PTCY/ ATG can reduce the risk of GVHD as compared with standard-dose ATG in haploidentical donor stem cell transplantation. In our study, the novel GVHD prophylaxis regimen, semi-dose PTCY (25mg/kg×2d) combined with low-dose ATG (1.5mg/kg×3d), was used for stem cell transplantation from haploidentical and unrelated mismatched donors. The incidence of III-IV aGVHD was 7.5% and cGVHD was 10.0%, and there was no rejection of the transplant. The activation rate of CMV and BKV was significantly lower than reported in the literature, and the non-relapse mortality (NRM) after transplantation was significantly reduced. There was no statistical difference in the rate of OS, EFS, aGVHD, and cGVHD between Group Haplo-RD and Group UD. The results provide an effective approach for preventing GVHD and infectious diseases in thalassemia patients who underwent allo-HSCT with high-risk GVHD.

Efficacy and Safety of a Novel Non-Myeloablative Conditioning Regimen for Hematopoietic Cell Transplantation in Adults with Severe Aplastic Anemia

Introduction The distinct "age effect" that exists in severe aplastic anemia (SAA) following hematopoietic cell transplantation (HCT) favors the use of reduced intensity conditioning regimens in patients >40 years. For older adults, overall survival and disease-free survival (DFS) is reduced with increasing age and unrelated donor transplant are associated with higher rates of graft failure, Epstein-Barr virus (EBV) reactivation, and post-transplant lymphoproliferative disorders (PTLD) (Rice C, et al. BBMT 2019.). To overcome this, a novel, non-myeloablative conditioning regimen called FCR, which consists of fludarabine, cyclophosphamide, and rituximab, was designed at Vanderbilt University Medical Center (VUMC) and the associated VA Tennessee Valley Healthcare System (TVHS) for use in all SAA patients. This regimen was subsequently evaluated in the first 11 SAA patients treated at VUMC/TVHS and found to result in lower toxicity, graft-versus-host disease (GVHD), and viral reactivation with no graft failure or relapse compared to historical controls (Gatwood KS, et al. BMT 2018.). Given these initial favorable results, FCR has now been expanded as the preferred conditioning regimen for all SAA patients undergoing HCT at our center, warranting follow-up evaluation in a larger cohort. Methods Utilizing institutional registries, all SAA patients were identified who underwent first allogeneic HCT using an FCR regimen (Figure 1) between January 2016 and May 2022. VUMC and TVHS Institutional Review Boards approved this retrospective analysis. Outcomes analyzed included time to engraftment, incidence of graft failure, incidence of acute GVHD (aGVHD) and chronic GVHD (cGVHD), rate of viral reactivation, post-HCT disease status, and number of inpatient hospital days through day +100. An analysis of 1-year GVHD-free, relapse-free survival (GRFS) was conducted in evaluable patients, with differences between the curves determined using log-rank tests. Results Twenty-four SAA patients underwent HCT from January 26, 2016 to May 11, 2022, the majority of which were male with a median age of 43.5 years (range: 22-62). All patients received at least one line of therapy prior to HCT with the most common treatment being the combination of cyclosporin A with anti-thymocyte globulin with or without eltrombopag and/or corticosteroid. Median time from diagnosis to transplantation was 434.5 days (range: 84-6408). Patients received transplants from matched related (n=8), haploidentical (n=2), and matched unrelated donors (n=14) using either a peripheral blood (PB) or bone marrow (BM) stem cell source (PB=15, BM=9). Median time to neutrophil and platelet engraftment was 14 days (range: 10-25) and 18 days (range: 10-38), respectively. No patients experienced graft failure. At median follow-up of 806.5 days (range: 72-2180) post-transplant, all patients were alive and in remission. No patients developed grade III-IV aGVHD and no differences in grade I-II aGVHD rates were noted based on stem cell source. By date of last follow-up, mild to moderate cGVHD graded per 2014 NIH criteria developed in 7 and 3 patients, respectively. There were no cases of severe cGVHD. Only 2 patients experienced a viral reactivation (cytomegalovirus [CMV]=1, EBV=1) by date of last follow-up. The case of EBV reactivation did not require treatment and did not progress to PTLD. The median number of inpatient hospital days required post-engraftment through the first 100 days post-transplant was 5 days (range: 0-21). The unadjusted Kaplan-Meier estimate of 1-year GRFS was 86.3% (95% CI: 72.8%-100%) (Figure 2), with moderate cGVHD accounting for all GFRS events in the study cohort. Conclusions The use of our novel non-myeloablative conditioning regimen in SAA is well tolerated with 0% non-relapse mortality and 100% DFS with low GVHD rates at 1-year post-transplant. Despite a high-risk population with median age >40 years, using primarily matched unrelated donors, and majority peripheral blood stem cell source, there were no deaths and rates of complications remained low. This study further supports the findings of our previous study, redemonstrating low rates of toxicity, severe GVHD and viral reactivation with no graft failure, relapse, or mortality. The use of these regimens needs to be validated in a larger cohort as they have the potential to provide a new standard of care for pre-HCT conditioning in SAA patients. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A Phase II Study of Myeloablative Allogeneic Hematopoietic Stem Cell Transplantation for Acute Lymphoblastic Leukemia in Older Patients Using Fludarabine and Total Body Irradiation

Background: Older adults with acute lymphoblastic leukemia (ALL) have poor survival outcomes. Although allogeneic hemaptopoietic stem cell transplantation (allo-hsct) can be curative when used as consolidation after complete remission (CR), advanced age, limited performance status and comorbidities are risk factors for increased non-relapse mortality (NRM) after myeloablative allo-hsct. The 1-year disease-free survival (DFS) for patients ≥40 years who receive an allo-hsct for ALL is often estimated to be 40-50%. Previous studies have demonstrated the efficacy of Total Body Irradiation (TBI) based regimens in adults with ALL when combined with cyclophosphamide (Cy). High-dose Cy is, however, associated with cardiac, hemorrhagic and hepatic toxicities. Fludarabine (Flu) has emerged as a safer substitute of Cy (e.g. Flu/Bu replacing Bu/Cy) with favorable toxicity profile. Given the efficacy of TBI-based regimens in ALL, we hypothesized that a myeloablative regimen of Flu/TBI 12 Gy is almost as effective as Cy/TBI 12 Gy in older adults with ALL undergoing allo-hsct.Methods: We conducted a single center, single-arm phase II clinical trial (NCT01991457) of Flu 40 mg/m 2 IV daily (days -7 to -4) and TBI 2 Gy X2 (days -3 to -1) (12 Gy total) as myeloablative conditioning for older adults (≥40 years old) or younger adults with significant comorbidities with ALL. The primary endpoint of the study was DFS. Secondary endpoints include overall survival (OS), relapse rate, NRM rate and incidence and severity of acute and chronic graft vs. host disease (GVHD). GVHD prophylaxis consisted of Tacrolimus and Methotrexate. Rabbit anti-thymocyte globulin (rATG) was added for unrelated donor type.Results: Nineteen patients were enrolled between October 2013 and February 2019 (Table 1). The median age was 54 years (44-63 years). There were 9 (47%) females and 19 (100%) Non-Hispanic Whites (NHW). The median KPS was 80 (70-100) and 3 (16%) patients had an HCT-CI of ≥3.Seven (37%) patients had Ph-negative B-cell ALL, 9 (47%) had Ph-positive B-cell ALL and 3 (16%) had lymphoid blast phase of chronic myeloid leukemia (CML-LBP). All patients were in CR1 at the time of transplant. Twelve (63%) patients had an 8/8 matched unrelated donor (MUD) and 7 (37%) had a matched related donor (MRD). The median time to neutrophil engraftment was 12 days (10-24 days). Day 100 post-transplant grades III-IV non-hematological and non-infectious adverse effects included mucositis (16%), acute kidney injury (16%), cardiovascular (11%) and elevated liver enzymes (5%).The cumulative incidence (CI) of grades II-IV and III-IV aGVHD at day 100 post-transplant was 26.1% (95% CI 19.3%-39.2%) and 16.2% (95% CI 12.4%-31.3%), respectively. The 2-year CI of mild, moderate and severe cGVHD was 5.0% (95% CI 2.1%-12.3%), 11.3% (95% CI 7.4%-33.3%) and 21.1% (95% CI 13.5%-40.3%), respectively (Table 2). There were 4 cases of cGVHD of the lungs (3=severe, 1=moderate). Other organs involved included skin (n=5), oral (n=5) and ocular (n=4).The CI of relapse and NRM at 2-years was 7.1% (95% CI 5.4%-20.7%) and 31.4% (95% CI 19.4%-50.1%), respectively (Figure 1). The 2-year DFS and OS rates were 63.2% and 68.4%, respectively (Figure 2a and 2b). The median OS was 40 months (95% CI 8.5-71.5).Conclusion: Flu/TBI (12 Gy) resulted in low incidence of relapse with a high DFS and OS rate in an older population with ALL. Increased incidence of severe cGVHD of the lungs was observed with this regimen. Further investigation into this regimen, as a myeloablative regimen for older patients with ALL, is warranted. [Display omitted] DisclosuresDi Stasi: University of Alabama at Birmingham: Current Employment; Syndax Pharmaceutical: Honoraria, Membership on an entity's Board of Directors or advisory committees. Saad: Incyte Pharmaceuticals: Consultancy; careDx: Consultancy; Amgen: Research Funding; Kadmon: Research Funding; OrcaBio: Research Funding; Magenta Therapeutics: Consultancy.

Machine Learning Reveals Patient Phenotypes and Stratifies Outcomes in Chronic Graft-Versus-Host Disease

Background: Chronic graft-versus-host disease (cGVHD) contributes to significant morbidity and mortality post hematopoietic stem cell transplant. Establishing a reliable classification system for this biologically and clinically heterogenous disease, remains challenging. Current scoring systems (e.g., NIH consensus criteria) calculate a score of mild, moderate, or severe disease from multiple organ domains. However, important information about the biology of disease and subtypes of patients may be lost when using the aggregate NIH overall severity classification that combines multiple dimensions of organ data. Machine learning may thus reveal subgroups in multi-dimensional data.Aim: We previously utilized a machine learning workflow on a training dataset to cluster cases of cGVHD into seven distinct phenotypes and designed a user-facing prognostic tool organized as a decision tree (Gandelman et al., Haematologica 2018). This decision tree identified clusters of patients with different survival trends that were not explained or stratified by NIH Severity alone. We sought to validate and expand this workflow on an independent cohort of patients from BMT CTN Study #0801.Methods: With permission from CIBMTR, clinical data were obtained from patients enrolled in BMT CTN #0801, a Phase II/III, prospective, multi-center comparative study. The cohort size started at 151 patients; 19 patients were excluded because of missing organ scores, leaving 132 patients in the final analysis. In the training dataset, it was determined that clusters were stable with N=130 patients in the analysis. Therefore, the sample size of the BMT CTN data set was adequate for the validation. At enrollment, NIH 2005 consensus criteria scores were recorded for eye, liver, joint, mouth, gastrointestinal tract, and lung. The percentage of the body surface area with erythema (% erythema) was measured. Skin sclerosis and fascia were assessed using Hopkins scores.Eight organ domains (NIH Scores 0-3: eye, liver, joint, mouth, gastrointestinal tract; Hopkins Scores: Sclerosis 0-4, Fascia 0-3; % erythema) were analyzed via a machine learning workflow consisting of t-distributed stochastic neighbor embedding (t-SNE), self-organizing maps (FlowSOM), and marker enrichment modeling (MEM). These steps allowed for dimensionality reduction, patient clustering, and organ enrichment scoring.Lung scores were not included as they were not found to contribute significantly to patient clustering in the training dataset analysis. All analyses were performed using R v4.0.4 and its libraries.Results: Baseline characteristics of patients in the validation cohort were similar to those of the training dataset except for disease stage, as a greater proportion of patients in the validation cohort had early-stage disease versus intermediate or high risk (p = 0.0004). The machine learning workflow identified similar phenotypic clusters in the validation cohort, with the sclerotic and liver-predominant clusters preserved most robustly (Figure 1A). As with the training dataset, machine learning identified clusters of phenotypes different from severity alone as assessed by the NIH global severity score in the validation cohort.Mean time from stem cell transplant to cGVHD (ie. probability of being cGVHD-free) was comparable between the two cohorts (284 days in validation cohort versus 288 days in training dataset). Notably, as with the training cohort, “Sclerotic” cluster patients in the validation cohort had significantly longer time from stem cell transplant to cGVHD compared to patients from other clusters (Log-rank: p = 0.0032) (Figure 1B).Conclusion: Our machine learning workflow identified phenotypic clusters with high fidelity and stratified time-to-GVHD in a validation cohort of patients. The decision tree tool separated patients into phenotypic clusters as previously designed in R by clustering with FlowSOM on t-SNE axes and using MEM to quantitively describe the clusters based on organ scores. Further studies on other independent cohorts of patients are now needed to delineate the biological basis of cGVHD subtypes and to further define patients in mixed phenotype groups. [Display omitted] DisclosuresJagasia: Iovance Biotherapeutics: Current Employment, Current holder of stock options in a privately-held company.

Late-Onset Acute and Chronic Graft-versus-Host Disease in Children: Clinical Features and Response to Therapy

Although acute graft-versus-host disease (aGVHD) and chronic GVHD (cGVHD) are known causes of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT), the syndrome of late aGVHD is less well understood, particularly in children. We aimed to characterize the clinical features and response to therapy of late aGVHD and cGVHD by retrospectively reviewing 573 consecutive patients age <18 years who underwent their first allogeneic HCT at the University of Minnesota. We included patients with de novo late aGVHD (ie, first occurrence of aGVHD after day +100 post-HCT) and cGVHD. We retrospectively scored cGVHD cases based on the 2014 National Institutes of Health guidelines. At 3 years, 9 patients (2%) had developed late aGVHD, 16 (3%) had overlap cGVHD, and 7 had (1%) classic cGVHD. No cases of joint or genital cGVHD were observed. The overall response to therapy at 6 months was 78% (95% confidence interval [CI], 40% to 97%) after late aGVHD and 43% (95% CI, 23% to 66%) after cGVHD. Higher nonrelapse mortality from day +100 was seen in patients with cGVHD but not in those with late aGVHD compared with patients without GVHD (hazard ratio, 3.6 [95% CI, 1.3 to 10.0] and 1.6 [95% CI, 0.2 to 11.7], respectively). We found variable organ involvement and treatment responses between patients with late aGVHD and those with cGVHD in a single-center pediatric cohort. Further research is needed to investigate the risks and clinical features of late aGVHD and cGVHD in larger cohorts to better understand how to tailor even more effective GVHD preventive and therapeutic approaches in children.

Naïve Helper T-Cell and Regulatory T- and NK-Cell Subsets Are Associated with Pediatric Chronic Graft-Versus-Host Disease: Results of the ABLE / PBMTC 1202 Study

Pediatric chronic graft-versus-host disease (cGvHD) contributes to poor quality of life and increased morbidity and mortality in long term survivors of hematopoietic stem cell transplant (HSCT). Given the insidious nature of cGvHD, diagnosing cGvHD in children according to the National Institutes of Health Consensus Criteria (NIH-CC) can be challenging, particularly in the early phase of disease development. Diagnostic cGvHD biomarkers could aid in diagnosis. The Applied Biomarkers of Late Effects / Pediatric Blood and Marrow Transplant Consortium (ABLE / PBMTC 1202) study was a prospective, multi-institution study at 27 pediatric HSCT centers that evaluated biomarkers of cGvHD. Detailed clinical evaluation of cGvHD, including central adjudication when necessary, occurred as per the NIH-CC. Of the 302 enrolled children, 233 were included in this diagnostic cGvHD biomarker analysis, including 43 with cGvHD and 190 non-cGVHD controls. Peripheral blood was drawn into a STRECK tube at the onset of cGvHD and before escalation of immune suppression, sent overnight to a central laboratory, and evaluated by flow cytometry. Five flow cytometric antibody panels consisting of 76 combinations of cell surface markers were used to delineate subpopulations of T, Regulatory T (Tregs, CD4+CD127LowCD25+), B, NK, and myeloid cells. We analyzed each marker in two ways. First, to control for normal post-HSCT immune reconstitution, we divided cGvHD subjects into early- (day 0-120), mid- (day 121-240), and late-onset (&amp;gt;day 240) and compared their marker values against non-cGVHD controls at day 100, 6-months, and 12-months, respectively, using fixed effect linear regression models. Second, we compared the marker values of all cGvHD subjects at diagnosis against the marker values of non-cGvHD controls at all three time points and used mixed effect linear regression models to account for within-subject correlations. A cellular subpopulation was considered a clinically relevant and potential diagnostic cGvHD biomarker if all 4 criteria were met: a) the effect ratio (mean marker value of cGvHD subjects over non-cGvHD controls) was ≥1.3 or ≤0.75, b) the p-value was ≤.05, c) the receiver-operating characteristic area under the curve was ≥0.60, and d) the marker was detected by both the mixed effect model and in the same direction across all measurement time points in the fixed effect models. Using these criteria, 8 cellular subpopulations arose as potential diagnostic biomarkers of pediatric cGvHD (Table). Key subsets identified in cGvHD patients included decreased proportions of naïve helper T cells (CD4+CD45RA+, PD1-CD4+CD45RA+, CCR7+CD4+CD45RA+, CD27+CD4+CD45RA+), decreased naïve and recently emigrated Tregs (CD31+CD45RA+, PD1-CD45RA+), and decreased non-cytolytic regulatory NK cells (CD56BrightCD335High, CD56BrightPerforinLow). CD4+ recent thymic emigrants (CD4+CD31+CD45RA+), markers of thymopoeisis, were also significantly decreased in cGvHD (p=0.01) but did not meet all the required biomarker criteria. Evaluation of specific subsets of pediatric cGvHD showed that CD21LowCD19+ B cells were lower in patients with pulmonary (n=12) compared to a mucocutaneous predominant phenotype (n=31) (p=0.048). Cases of progressive cGvHD (n=18), characterized by concurrent acute GvHD features (overlap syndrome), had decreased proportions of CD19 B cells, T3 transitional B cells (CD38LowCD10-) and mature naïve B cells (IgD+CD27-), decreased naïve helper T cells (CCR7+CD4+CD45RA+) and increased activated NK cells (CD56dimCD69+) (all p&amp;lt;0.05). No cellular subsets were associated with the number of organ systems involved with cGvHD or global cGvHD severity according to the NIH-CC. Using a well characterized cohort of pediatric patients with cGvHD, the ABLE / PBTMC 1202 study showed that a variety of subpopulations of naïve helper T cells, Tregs, and regulatory NK cells were associated with cGvHD. Additional B-cell markers were associated with progressive cGvHD in children. These data support alterations in thymopoeisis and decreases in regulatory T- and NK-cell populations underlying pediatric cGvHD. Future work includes the addition of non-cellular plasma markers into a clinically applicable diagnostic biomarker algorithm to aid clinicians in the accurate diagnosis of pediatric cGvHD, as well as further validation in the ABLE 2.0 / Pediatric Transplant Cellular Therapy Consortium 1901 study. Disclosures Wahlstrom: Pharmacyclics: Current Employment. Pulsipher:Mesoblast: Honoraria; Adaptive: Research Funding; Miltenyi: Honoraria, Research Funding; Bellicum: Honoraria; Jasper: Honoraria; Novartis: Honoraria.

434 Association of skin response in erythema and sclerosis with survival in chronic graft-versus-host disease

Skin is the most commonly affected organ in chronic graft-versus-host disease (cGVHD). Though causing significant morbidity, skin is not a common direct cause of mortality. We report survival associations of complete (CR) vs partial (PR) and no cutaneous response (NR). Using the cGVHD Consortium, a prospective observational study of cGVHD patients from 2007-2017 at 9 centers, we studied patients who were enrolled <3 months (incident) or >=3 months (prevalent) after diagnosis of cutaneous cGVHD and within 3 years of transplant. We used the 2005 NIH criteria to designate CR, PR, or NR in erythema or sclerosis at the 2nd study visit. Cox regression models were used to predict subsequent overall survival (OS) and non-relapse mortality (NRM) based on skin response. Of 468 consortium patients, 185 (40%) had erythema at entry of whom 136 (74%) achieved CR at the 2nd visit, 9% PR, 18% NR, with similar response in incident and prevalent erythema. At entry, 89 (19%) patients had sclerosis. Response was higher in incident (68% CR, 2% PR, 30% NR) compared to prevalent sclerosis (28% CR, 4% PR, 68% NR). Erythema CR in prevalent cases correlated with improved OS (median OS 1858 vs 1026 days, HR 0.29, 0.09-0.89, p=0.03) and NRM (median NRM 1194 vs 1026 days, HR 0.26, 0.08-0.92, p=0.04). CR of incident erythema was weakly associated with improved OS and NRM, with a stronger effect in the subgroup with additional affected organs. Though underpowered, CR of sclerosis had similar trends of improved OS and NRM in both incident and prevalent groups. Most incident cases of cGVHD have CR in both sclerosis and erythema by the following visit. Cutaneous CR is associated with improved survival times up to and exceeding 2 years. Sclerosis present <3 months from cGVHD diagnosis is twice as likely to resolve as sclerosis present later in the disease.

Retrospective Multicenter Study of Extracorporeal Photopheresis in Steroid-Refractory Acute and Chronic Graft-versus-Host Disease

Extracorporeal photopheresis (ECP) is an established treatment strategy in steroid-refractory graft-versus-host disease (GVHD). This study's main objective was to analyze the clinical response and impact of ECP therapy in steroid dose reduction. A retrospective observational series of 113 patients from 7 transplantation centers was analyzed. Sixty-five patients (58%) had acute GVHD (aGVHD), and 48 (42%) had chronic GVHD (cGVHD). All ECP procedures were performed with the off-line system. The median number of procedures until achievement of initial response was 3 for both patients with aGVHD and those with cGVHD. ECP was the second-line therapy in 48% of the aGVHD cases and in 50% of the cGVHD cases. 71% of the cases of aGVHD were grade III-IV, and 69% of the cases of cGVHD were severe. The overall response rate on day 28 was 53% (complete response [CR] rate, 45%) in the patients with aGVHD and 67% (CR, 23%) in those with cGVHD. Skin was the most frequently involved organ, with a response rate of 58% (CR, 49%) in the patients with aGVHD and 69% (CR 29%) in those with cGVHD. At the end of ECP treatment, 60% of patients treated for aGVHD who responded were able to stop steroid therapy, with a median dose reduction of 100%. Significant differences in overall survival were observed for patients responding to ECP with aGVHD (hazard ratio [HR], 4.3; P < .001) and with cGVHD (HR, 4.8; P=.003). Our data indicate that ECP is a valid therapeutic alternative in patients with steroid-refractory aGVHD and cGVHD, permitting significant steroid dosage reductions.

Targeting Bcl-2 and CD38 As Part of Personalized HSCT Conditioning Regimen in Chemorefractory Acute Leukemia in Children

Introduction The outcome HSCT in a cohort of children with chemorefractory acute leukemia (AL) is poor. The incidence of relapse exceeds 50% and survival varies from 10 to 40%. Additional attempts at remission induction with various combinations of chemotherapy are unlikely to improve the outcome and may contribute to toxicity. We hypothesized that personalized targeted therapy combined with high-dose preparative regimen may improve the outcome of alloHSCT in a cohort of pediatric patients with refractory AL. Bcl-2 and CD38 were chosen as potential targets due to frequent expression in pediatric acute leukemia, availability of marketed targeted therapies, venetoclax and daratumumab, and expected non-overlapping toxicity profile of these agents and the conditioning regimen. Materials and methods A total of 26 pts with chemorefractory acute leukemia (AML-18, T-ALL-6, ABL-2, primary refractory - 9, refractory relapse - 17, 18 male, 8 female, median age 11.3 years), underwent HSCT between November 2017 and May 2019. All patients were transplanted from haploidentical donors, all patients had active disease (AD) at the moment of SCT. For 19 (73%) pts it was the first alloHSCT, for 7 (27%) pts it was the second HSCT. Median bone marrow leukemia burden before cytoreduction was 11% (3-90). Bcl-2 expression on the tumor cells was detected in 23 pts with the median expression of 58% (1.5-99), CD38 expression was detected in 24 pts with the median expression of 88% (11-100). Thirteen pts received treosulfan-based conditioning and 13 - TBI-based (12 Gy). TBI was used among patients with second HSCT (n=7), patients with T-ALL (n=4) and patients with massive extramedullary disease (n=2). GvHD prophylaxis included tocilizumab at 8 mg/kg on day -1 and abatacept at 10 mg/kg on day -1, +7, +14, +28. According to the expression of Bcl-2 and CD38 on tumor cells, 24pts (92%) received daratumumab (anti-CD38 monoclonal antibody) on day -7 at 10-16 mg/kg, 21 pts (81%) received venetoclax at 300 mg/m2/day on days -7 to -2 and 12 pts additionally received plerixafor at 240 mcg/kg x 3 on days -7 to -5. TCRαβ+/CD19+ depletion of PBSC with CliniMACS technology was implemented in all cases. The median dose of CD34+ cells in the graft was 9.5 x106/kg (range 4.9-13.3), αβ T cells - 26.5x103/kg (range 5.6- 84). Modified (CD45RA-depleted) donor lymphocyte infusions (DLI) were administered prophylactically in all pts. Results Two patients died before engraftment due to septic event. Primary engraftment was achieved in 24 of 24 evaluable pts (100%), the median time to neutrophil and platelet recovery was 12 and 13 days. All pts achieved complete remission on day +30. There were no significant toxic effects after targeted therapy, 4 pts (21%) had daratumumab-related infusion reactions, one patient with T-ALL died after engraftment due to septic event. aGVHD grade I-II developed in 5 pts (20%), two of them required systemic immunosuppressive therapy. There were no cases of aGVHD &amp;gt; grade II, neither cases of cGVHD. The median NK- cells count by the day +30 was 0.07 x 106/ml (range 0.01- 0.4), the median levels of αβ T cells and gd T cells were 0.018 x 106 /ml (range 0 - 1.1) and 0.015 x 106 /ml (range 0,01 - 1.3), respectively. Nine (37.5%) pts (5 with T-ALL, 1 with ABL, 3 with AML) relapsed, median interval to relapse was 103 days (55-345). At the moment of reporting 14 (53%) patients are alive in complete remission with a median follow up of 12.7 months (1.9-23m). Event-free and overall survival at 1 year for AML are 76% (SE13) and 76% (SE14), all patients with T-ALL and one with ABL died of disease progression. Conclusion We suggest that addition of venetoclax and daratumomab to the backbone of myeloablative haploidentical HSCT with αβ T cell depletion is not associated with increased toxicity and may lead to improved outcome in a cohort of pediatric patients with chemorefractory AML. In a subgroup of patients with T-ALL this approach does not seem to produce visible benefit. This approach can be further tested in a prospective trial with the goal to increase the anti-leukemic efficacy of HSCT. Figure Disclosures Maschan: Miltenyi Biotec: Other: lecture fee. Off Label Disclosure: venetoclax daratumomab plerixafor

Results of a Multicentre, Randomized, Controlled Open-Label Study on the Use of Anti-T-Lymphocyte Globulin (ATLG) and Rituximab for Immunomodulation of Graft-Versus-Host Disease (GvHD) and Graft Failure (GF) in Patients with Non-Malignant Disorders

BACKGROUND: Allogeneic hematopoietic stem-cell transplantation (allo-HSCT) is increasingly used to treat a wide range of non-malignant disorders. However, the optimal strategy to be employed for GvHD prevention remains a matter of debate. In particular, the use of ATLG for the prevention of immune-mediated complications in patients transplanted from a matched-related donor (MRD) is still controversial. In the matched unrelated donor (MUD) setting, there is retrospective evidence that Rituximab used as prophylaxis of EBV viremia may protect from acute GvHD (aGvHD) development, but the clinical benefit of pre-transplant Rituximab has never been assessed in prospective randomized studies. METHODS: We conducted a multicentre, randomized, open-label, trial (NCT01810926) in 5 Italian centres enrolling patients with non-malignant haematological and inherited metabolic disorders transplanted from either a MRD or a MUD, selected using high-resolution typing for HLA-class I/II loci and stringent criteria of HLA-compatibility (&gt;9/10). All patients received the same myeloablative regimen consisting of Treosulfan, Thiotepa and Fludarabine. Enrolled patients were randomized (1:1) to receive either standard or intensified GvHD prophylaxis. Cyclosporine-A plus short-term methotrexate was the standard GvHD prophylaxis in MRD HSCT recipients. In the experimental arm, patients were additionally given ATLG (Grafalon®, Neovii, 5 mg/kg/day on day -4,-3, and -2). In patients transplanted from a MUD, standard GvHD prophylaxis consisted of Cyclosporine-A plus short-term methotrexate and ATLG (10 mg/kg on day -4,-3 and-2). In the experimental arm, patients were additionally given Rituximab 200 mg/sq on day -1 (Mabthera®, Roche). In MRD group randomization was stratified by disease (hemoglobinopathies vs. other conditions) and in the MUD group by center. For patients given MRD HSCT, the primary end-point was the probability of survival (SUR) free from: a) primary and secondary GF, b) grade II-IV aGvHD, c) chronic GvHD (cGvHD), d) death, whichever occurred first. For patients transplanted from a MUD, the primary end-point was the SUR probability free from: a) grade II-IV aGvHD, b) EBV viremia (&gt;1,000 copies of viral DNA/ml whole blood), whichever occurred first. Secondary endpoint was overall SUR (OS). Statistical analyses were conducted according to intention-to-treat. FINDINGS: Between August 2011 and February 2018, 126 patients were enrolled. Patient and disease characteristics by randomized treatment are shown in Table 1. Median age at HSCT was 6.1 years in the MRD group (range 0.8-38) and 4.9 years in the MUD group (range 0.9-20.7). Median follow-up was 3.6 years. Among the 51 MRD-HSCT recipients, 25 were randomly assigned to the ATLG group and 26 to the NO-ATLG group. No death and no cases of grade II-IV aGvHD were observed in either of the two randomization arms. Two GF occurred in each of the two arms, while 1 and 2 cases of cGvHD occurred in the ATLG and NO-ATLG groups, respectively. Consequently, no statistically significant difference in the probability of SUR without events was observed (p=0.75) and the 3-years estimates (±SE) were 86.9%±7.1% vs. 83.8%±7.5%, respectively. In the MUD setting, 38 patients were allocated in the Rituximab group and 37 in the NO-Rituximab group. Although no statistically significant difference in OS (p=0.21) was observed between the two arms (3-years estimates: 94.1%±4.1% for Rituximab, 85.7%±5.9% for No-Rituximab), patients receiving Rituximab had a better probability of SUR without events (73.0%±7.3% vs 26.5%±7.3%, respectively; p=0.0002), entirely due to a lower incidence of EBV viremia. One case of fatal post-transplant lymphoproliferative disorder was observed in the No-Rituximab arm. Eight patients developed grade II-IV aGvHD in each of the two arms. No patient has persistent dependence on ivIG replacement therapy. CONCLUSIONS Our data indicate that, in patients with non-malignant disorders given a MRD HSCT, the addition of ATLG does not confer any advantage in the prevention of both acute and chronic GvHD, as well as of GF. In MUD-HSCT recipients, the administration of a fixed dose of pre-transplant Rituximab as part of the conditioning regimen does not affect the risk of aGvHD and transplant-related mortality, while it significantly reduces the incidence of episodes of EBV-viremia, without impairing B-cell recovery. Disclosures Algeri: Bluebird bio: Consultancy, Honoraria; Miltenyi: Honoraria; Atara Biotherapeutics: Consultancy, Honoraria. Merli:Novartis: Honoraria; Sobi: Consultancy; Amgen: Honoraria; Bellicum: Consultancy. Locatelli:Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; bluebird bio: Consultancy; Miltenyi: Honoraria; Bellicum: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Effects of chemotherapy combined with donor lymphocyte infusion on chronic graft-versus-host disease and prognosis in minimal residual disease positive patients after allogeneic hematopoietic stem cell transplantation

目的探讨异基因造血干细胞移植（allo-HSCT）后微小残留病（MRD）阳性患者接受化疗联合供者淋巴细胞输注（Chemo-DLI）后慢性移植物抗宿主病（cGVHD）的临床特点以及其严重程度对患者预后的影响。方法纳入接受allo-HSCT后出现MRD阳性的急性白血病患者，给予Chemo-DLI治疗，采用美国国立卫生研究院（NIH）标准评估cGVHD的特点及严重程度，并分析其对预后的影响。结果共有54例（59.3%）患者在Chemo-DLI后出现cGVHD，中位发生时间为DLI后70（13~504）d。分别有6例（6.6%）、21例（23.1%）、27例（29.7%）患者发生轻度、中度、重度cGVHD。未发生cGVHD、轻中度cGVHD、重度cGVHD患者Chemo-DLI后5年复发率分别为61.9%（95%CI 45.3%~78.5%）、15.1%（95%CI 1.1%~29.1%）、26.6%（95%CI 9.2%~44.0%）（χ2=18.901，P<0.001）。未发生cGVHD、经典型cGVHD、重叠综合征患者Chemo-DLI后5年复发率分别为61.9%（95%CI 45.3%~78.5%）、19.9%（95%CI 8.1%~31.7%）、28.6%（95%CI 0.0%~65.0%）（χ2=18.307，P<0.001）。cGVHD与治疗后的非复发死亡无关。未发生cGVHD、轻中度cGVHD、重度cGVHD患者Chemo-DLI后5年无白血病生存（LFS）率分别为24.0%（95%CI 9.1%~38.9%）、77.2%（95%CI 60.8%~93.6%）、64.9%（95%CI 45.7%~84.1%）（χ2=24.447，P<0.001）。未发生cGVHD、经典型cGVHD、重叠综合征患者Chemo-DLI后5年LFS率分别为24.0%（95%CI 9.1%~38.9%）、75.5%（95%CI 62.7%~88.3%）、42.9%（95%CI 1.8%~84.0%）（χ2=25.665，P<0.001）。未发生cGVHD、轻中度cGVHD、重度cGVHD患者Chemo-DLI后5年总生存（OS）率分别为50.0%（95%CI 31.1%~68.9%）、87.9%（95%CI 74.7%~100.0%）、71.0%（95%CI 52.0%~90.0%）（χ2=9.517，P=0.009）。未发生cGVHD、经典型cGVHD、重叠综合征患者Chemo-DLI后5年OS率分别为50.0%（95%CI 31.1%~68.9%）、83.9%（95%CI 72.8%~95.0%）、51.4%（95%CI 6.2%~96.6%）（χ2=10.673，P=0.005）。多因素分析显示，移植前处于第1次完全缓解期、经典型cGVHD与Chemo-DLI后较低的复发风险和较好的生存相关。结论在allo-HSCT后MRD阳性患者中，Chemo-DLI干预后的cGVHD可以降低急性白血病患者的复发风险并改善生存；表现为重叠综合征的患者，需要积极控制cGVHD以改善预后。

Administration of BPX-501 Cells Following Αβ T and B-Cell-Depleted HLA-Haploidentical HSCT (haplo-HSCT) in Children with Malignant or Non-Malignant Disorders

BackgroundAllogeneic hematopoietic stem cell transplantation (HSCT) is an established treatment for children with leukemia or life-threatening non-malignant disorders. Approximately 25% of patients have a HLA-matched sibling and ~50% have a suitable matched unrelated donor, leaving ~25% of patients who require an alternative donor. HLA-partially matched (haploidentical, haplo) donors represent a suitable alternative for these children; extensive T-cell depletion of the graft is largely employed to minimize the risk of graft-versus-host disease (GvHD).BPX-501 is an allogeneic product consisting of T cells modified to express the inducible caspase-9 (iC9) safety switch and truncated CD19 to allow monitoring and expansion of CD3+ CD19+ T-cells following transplant. The polyclonal nature of the BPX-501 T cells provides broad virus and tumor-specific immunity, while the safety switch provides the unique ability to promptly and durably resolve graft-versus-host disease (GvHD) symptoms following the administration of rimiducid.AimsTo evaluate the safety and efficacy of BPX-501 T cells administered after a T-cell receptor αβ and B-cell-depleted haplo-HSCT in pediatric patients with malignant or non-malignant disorders. The primary endpoint is event-free survival at 180 days (events include TRM (or NRM for malignant patients), severe GVHD (acute Grade 2-4 organ or extensive chronic GVHD) and life-threatening infections (Grade 4).MethodsThis multicenter EU (NCT02065869), prospective trial utilizes αβ-T and B-cell-depleted haplo-HSCT followed by infusion of donor lymphocytes genetically modified with iC9 (BPX-501). BPX-501 cells were planned to be infused on day14±4 after the allograft. No post-transplant pharmacological GvHD prophylaxis was employed. Patients who develop GvHD resistant to conventional steroid therapy could receive ≥1 dose of dimerizing rimiducid activating iC9.The efficacy evaluable population (EEP) was defined as any patient who received HSCT, BPX-501 infusion and at least one follow-up assessment.ResultsAt the time of clinical cut-off (June 30, 2018) 166 patients met the EEP definition. All patients were from EU sites. Key baseline and transplant characteristics are shown in Table 1.In patients who obtained sustained engraftment of donor cells, the median time for neutrophil and platelet engraftment was 16 (15-17) and 11 (11-12) days, respectively. No patients experienced graft failure. Thirty-one patients developed Grade I-IV aGvHD (18.7% [95% CI;12.8 - 24.7%]). Three patients developed Grade III-IV aGvHD (1.8% [95% CI; 5.2 - 14.1%]). Of 132 evaluable patients, 9 developed cGvHD (7.2% [95% CI; 2.6 - 11.7%]) with only 2 patients experiencing moderate - severe cGvHD (95% CI: 0.0 - 3.1). Rimiducid was administered to 11 patients. Ten patients had ≥ 1 response assessment following administration of rimiducid. The best overall response rate (CR/PR) was 100% with 9 patients (90%) achieving complete response.At the time of clinical cut off, EFS at 180 days was 92.7% (95% CI: 88.7 - 96.7%). An interim analysis with approximately 100 patients from a concurrent Matched Unrelated Donor (MUD) HSCT comparator trial and previously published data is planned for the time of the congress.At a median follow-up of 17.6 mos (1.5 - 43.7 mos) 5 patients experienced transplant related mortality (TRM) (3.3% [95% CI: 0.4 - 6.2%]). DFS was 89.4% (95% CI: 84.7 - 94.2%). Overall survival (OS) was 94.2% (95% CI: 90.5 - 97.9%).CD3+ and CD3+CD4+ T cells above 500 cells/ml were achieved by day 100. IgA and IgM levels achieved normal values by day 180. The percentage of circulating and median absolute BPX-501 T-cells at Day 100 were 9.06% ± 10.52% (0 - 54.9%) and 109.49 ± 213.99 cells/ml (0 - 1001 cells/ml), respectively.ConclusionPreliminary evaluation of the primary endpoint and additional time-dependent efficacy outcomes, shows that the adoptive transfer of BPX-501 T cells following αβ-T and B-cell depleted haplo-HSCT followed by infusion of BPX-501 represents a novel and highly effective transplantation strategy for pediatric patients with malignant or non-malignant disorders. Despite the addition of BPX-501, overall rates of GvHD were low with few cases of high-grade aGvHD or cGvHD. Rimiducid was shown to be an effective treatment for patients who developed steroid-refractory GvHD. [Display omitted] DisclosuresQasim:Bellicum: Research Funding; Autolus: Equity Ownership; Servier: Research Funding; Orchard: Equity Ownership. Slatter:Medac: Other: Travel assistance. Locatelli:bluebird bio: Consultancy; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bellicum: Consultancy, Membership on an entity's Board of Directors or advisory committees; Miltenyi: Honoraria; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Multicentric, Retrospective Study of Extracorporeal Photopheresis, Off-Line System, in Corticosteroid Refractory Acute and Chronic Graft-Versus-Host Disease

BACKGROUNDGraft-versus-host disease (GvHD) remains an important cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation, despite the improvements in GvHD prophylaxis. First line treatment of GvHD (acute or chronic) consists of high dose corticosteroids, with a response rate of around 50%. Extracorporeal photopheresis (ECP) is an effective and safe treatment strategy in corticosteroid refractory GvHD, although most of the studies are limited to retrospective series. The main objectives of this study were to analyze the clinical response and impact of ECP therapy in corticosteroid dose reduction.METHODS114 patients from 7 Spanish transplantation centers were analyzed retrospectively. The characteristics of the patients are shown on Table 1. A total of 1940 ECP procedures were performed from January-2011 to June-2017 in 65 patients (57%) with acute GvHD (aGvHD) and 49 (43%) with chronic GvHD (cGvHD). Glucksberg and the NIH criteria were used for the diagnosis and grading of acute and chronic GvHD, respectively. All ECP procedures were performed with the off-line system: after the lymphoapheresis, 8-MOP was added to the apheresis product and finally photoinactivated in the Macogenic G1 (Macopharma®) irradiator. During the first 4 weeks, patients underwent 1-2 weekly procedures, followed by 1-2 procedures every 2 weeks and tailored by clinical response. The response was classified as complete response (CR), partial response (PR) or no response (NR). % of the initial corticosteroid dose reduction was registered at the end of treatment.RESULTSPatients with aGvHD underwent a median of 13 processes (interquartile range 9-19), and those with cGvHD a median of 19 processes (IQR 13-24). The median number of processes until response was 3 in patients with aGvHD and 4 for patients with cGvHD. ECP was the second line therapy in the 47% of aGvHD cases and 49% in cGvHD. 71% of the cases of aGvHD were grade 3-4, and 69% of the cases of cGvHD corresponded to severe forms.The overall response rate in aGvHD was 66% (CR 55%), whereas in cGvHD the rate was 67% (CR 22%). The most involved organ was the skin, with a response rate of 80% (CR 68%) in aGvHD and 69% (CR 22%) in cGvHD. In acute digestive GvHD, the response rate was 61% (CR 50%), and 75% (CR 50%) in the chronic form. For liver involvement, response rates were 67% (CR 57%) in acute and 70% (CR 30%) in cGvHD. 80% of the patients with chronic lung involvement showed an overall response (20%CR). At the end of ECP treatment, 71% of the patients treated for aGvHD and 61% of patients with cGvHD were able to reduce the corticosteroid dose, with a median dose reduction of 90% and 100% in all patients, respectively.With a median follow-up of 31 months in aGvHD and 68 months in cGvHD, the 2-year overall survival (OS) was 47% and 83%, respectively. Significant OS differences were noted between responding (CR+PR, 2-year OS 62%) and no responding (NR, 2 year OS 18%, HR=2.5, p<0.001) aGvHD patients. Significant differences were also seen in cGvHD between responding (CR+PR, 2 year OS 93%) and no responding (NR, 2 year OS 62%, HR=3.99, p=0.008) patients.CONCLUSIONSECP is a valid therapeutic alternative in patients with corticosteroid refractory acute and cGvHD, with higher CR rates in patients with aGvHD. ECP allowed for significant corticosteroid dose reductions in more than 2/3 of the patients in both GvHD settings, and granted longer OS in responding patients. The results obtained are similar to those published by other groups. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Impact of Chronic Graft-versus-Host Disease on Late Relapse and Survival on 7,489 Patients after Myeloablative Allogeneic Hematopoietic Cell Transplantation for Leukemia.

Malignancy relapse remains a major obstacle for successful allogeneic hematopoietic cell transplantation (HCT). Chronic graft-versus-host disease (cGVHD) is associated with fewer relapses. However, when studying effects of cGVHD on relapse, it is difficult to separate from acute GVHD effects as most cases of cGVHD occur within the first year after transplant at the time when acute GVHD is still active. This study based on CIBMTR registry data investigated cGVHD and its association with the incidence of late relapse and survival in 7,489 patients with acute myelogenous leukemia (AML), acute lymphoblastic leukemia (ALL), chronic myelogenous leukemia (CML), and myelodysplastic syndromes (MDS), who were leukemia free at 12 months after myeloablative allogeneic HCT. Forty-seven percent of the study population was diagnosed with cGVHD at 12 months after transplant. The protective effect of cGVHD on late relapse was present only in patients with CML [RR, 0.47; 95% confidence interval (CI), 0.37-0.59; P < 0.0001). cGVHD was significantly associated with higher risk of treatment-related mortality (TRM; RR, 2.43; 95% CI, 2.09-2.82; P < 0.0001) and inferior overall survival (RR, 1.56; 95% CI, 1.41-1.73; P < 0.0001) for all diseases. In patients with CML, all organ sites and presentation types of cGVHD were equally associated with lower risk of late relapse. These results indicate that clinically relevant antileukemia effects of cGVHD on late relapses are present only in CML but not in AML, ALL, or MDS. Chronic GVHD in patients who are 1-year survivors after myeloablative allogeneic HCT is primarily associated with higher TRM and inferior survival.

Localization of Sclerotic-type Chronic Graft-vs-Host Disease to Sites of Skin Injury

The mechanisms responsible for the variable manifestations of chronic cutaneous graft-vs-host disease (cGVHD) are poorly understood. Localization of sclerotic-type chronic graft-vs-host disease to sites of skin injury (isomorphic and isotopic responses), a recognized phenomenon in morphea, suggests a potential common pathway between cGVHD and other sclerotic skin conditions. Four cases of sclerotic-type cGVHD developed at the site of disparate skin injuries (ionizing radiotherapy, repeated needle sticks, central catheter site, and varicella-zoster virus infection). We review the spectrum of previously reported cases of sclerotic and nonsclerotic cGVHD relating to external forces on the skin. Localization of sclerotic-type cGVHD may occur after many types of skin injury, including UV and ionizing radiotherapy, needle sticks, viral infection, and pressure or friction. Recognition of this phenomenon may be helpful for the early diagnosis of sclerotic disease. Recent insights into the immunological consequences of minor skin injury may provide important clues to the underlying pathogenesis of cGVHD-mediated skin disease.

Chronic Graft-Versus-Host (cGVHD) after Non-Myeloablative Stem Cell Transplantation (NST) with Rituximab-Containing Conditioning Regimens for Non-Hodgkin's Lymphoma.

Non-myeloablative stem cell transplantation is an effective strategy to reduce the incidence of acute (a) GVHD, a major risk factor for the development of chronic (c) GVHD. However, in NST there is evidence of at least a similar incidence of cGVHD compared with myeloablative transplants despite the lower incidence of aGVHD.Objective: To evaluate the incidence, natural history and outcome of cGVHD following NST in patients (pts) with Non-Hodgkin's Lymphoma.Methods: All pts were treated with NST with Fludarabine/Cyclophosphamide/Rituximab conditioning regimen (I. Khouri. Blood 2001), and tacrolimus/methotrexate for GVHD prophylaxis. Risk factors for the occurrence of de novo cGVHD were evaluated using Cox regression analysis.Results: 78 pts were treated: follicular lymphoma (n=47; 60%), diffuse large cell (n=16; 21%), and mantel cell lymphoma (n=15; 19%). Median age was 53 years (21–68). Donors were matched sibling (69/78; 88%), other related (n=3; 4%) and matched unrelated (n=6; 8%). Stem cell source was peripheral blood for related transplants and bone marrow for unrelated donor transplants. Median number of prior chemotherapy regimens was 3 (1–10). All pts but 5 (6%) had chemo-sensitive disease prior to transplant. Median follow up among survivors was 35 months (3–70). Grade I–IV aGVHD occurred in 25 pts (32%), II–IV in 15 (19%), and III–IV in 5 pts. There were 30 cases of cGVHD (3-yr cumulative incidence of 46%; 95% CI 35–60) including 20 de novo (3 yr cumulative incidence of 39%; 95% CI 27–56) and 10 with relapsing/progressive disease. Median time of onset of de novo GVHD was 277 days (126–798). Overall survival since the diagnosis of cGVHD was 92% (95% CI 54–99) in the novo group compared with 43% (95% CI 11–72) in the relapsing/progressive group. cGVHD was the primary cause for the only death in the de novo group and for 4 of 5 deaths in the relapsing/progressive group. Patients' characteristics (age, gender, donor-recipient histocompatibility, diagnosis, prior autologous transplantation, number of prior chemotherapy regimens, disease status prior to transplant (CR/PR), B2microglobulin, LDH, IPI, and patient/donor CMV serostatus), graft characteristics (CD34 and CD3 positive cells dose) and post-transplant course (CMV reactivation within 100 days post NST, chimerism at day 30 and day 90 post NST, time to tacrolimus taper, and use of DLI) were not significantly associated with the occurrence of de novo cGVHD.Conclusions: Despite a reduction in aGVHD, the incidence of cGVHD was comparable to that described after myeloablative regimens. Furthermore, there was a high incidence of de novo cGVHD, but a low cGVHD-related mortality. The lack of conclusive risk factors, including those traditionally associated with acute GVHD, emphasizes the potentially different pathophysiology and epidemiology of these 2 diseases.

Definition of Cytochrome P450 1A2 as a Target Autoantigen in the Hepatitic Variant of Hepatic Chronic Graft-Versus-Host Disease.

Chronic graft-versus-host disease (cGVHD) of the liver mimicking autoimmune hepatitis is an increasingly well recognized complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). The target antigens and pathogenesis of this complication are poorly understood. We describe a case of hepatitic cGVHD in which cytochrome P450 1A2 (CYP1A2) was identified as a target antigen. A 47 year old male received an HLA matched sibling transplant for acute myeloid leukemia with normal cytogenetics following 3 cycles of idarubicin, cytarabine and etoposide remission induction therapy. Conditioning was with fludarabine 50mg/m2 and cyclophosphamide 120 mg/m2. Both donor and recipient were CMV IgG positive. Standard cyclosporin and short course methotrexate GVHD prophylaxis was used. Due to mixed lymphoid chimerism, cyclosporin was tapered from D94, and a donor leukocyte infusion (DLI) given at D124. One month following DLI, concomitant with attainment of 100% donor lymphoid chimerism, the patient developed florid oral changes of cGVHD and striking elevation of hepatic transaminases (ALT and AST peaked at 3604 (R 0–55 IU/L) amd 2241 (R 0–45 IU/L) respectively) with relatively minor elevation in hepatic ductal markers (GGT 327, R 0–60 IU/L). Liver biopsy was consistent with autoimmune hepatitis. Multiple recipient serum samples at this time demonstrated the presence of a high titre anti-liver microsomal (LM) antibody (titre 1:1280 by indirect immunofluorescence) reminiscent of hydralazine-induced hepatitis and immunofixed an antigen of approximately 51 kDa by immunoblotting using human liver homogenate. Neither pre-transplant recipient nor donor sera were reactive. Immunoblotting for a panel of 13 CYP450 antigens demonstrated that the antibody was specific for CYP1A2. This specificity was confirmed with blocking and inhibition experiments. Sequencing of the entire coding region of the CYP1A2 gene did not identify any coding variants present in the recipient but not the donor. Oral prednisolone resulted in brisk improvement in hepatitis and oral cGVHD, and was ceased at 12 months post transplant. The patient remains well with no further GVHD over 2 years post transplant. This is the first description of a target antigen in hepatitic cGVHD. The mechanism is unclear, but does not appear to be a CYP1A2 polymorphism acting as a minor histocompatibility antigen. Induction of hepatic autommune-like responses have been described in liver transplant recipients receiving calcineurin inhibitors, and it is possible that cyclosporin facilitated an autoimmune-type response in this case. Characterisation of autoantibody responses in additional cases of hepatitic cGVHD will be of great interest. [Display omitted]