Post-allogeneic Hematopoietic Stem Cell Research Articles

Outcomes of HMA and Venetoclax in Relapsed AML Post-Allogenic Hematopoietic Stem Cell Transplant

Background: There is no standard of care treatment for Acute Myeloid Leukemia (AML) in relapse post-allogeneic hematopoietic stem cell transplant (post-HSCT), with overall 5-year survival about 5-10%. Venetoclax (Ven) is a novel BCL2 inhibitor approved by the FDA for treatment of newly diagnosed AML in combination with hypomethylating agents (HMA) or low dose cytarabine for patients unfit for intensive induction. However, data in relapsed/refractory AML are limited, especially in the post-HSCT setting. In this retrospective study, we reviewed outcomes of patients with AML relapse post-HSCT who received Ven in combination with HMA in a single center. Methods: Charts of 17 patients who had AML relapse post-HSCT treated with combination of Ven and HMA between November 2018 - March 2020 at the University of Kansas Medical Center were reviewed. We utilized descriptive statistics for baseline characteristics and outcomes, and Kaplan-Meier log-rank test for calculating overall survival. Results Seventeen patients received Ven+HMA for AML relapse post-HSCT in our center. At the time of SCT, patients were in first complete remission (CR) (n=15); second CR (n=1) and primary failure induction (1). Median age was 62 at time of relapse (31-71) years, and 8 patients were female (47%). 9 patients (53%) had adverse risk AML (ELN 2017) 8 of them were in CR1 and 1 with primary induction failure. Common mutations included DNMT3a, ASLX-1, TET2 (3); TP53 (2); IDH1/2 (2); NPM1/FLT3 (1); NPM1/IDH2 (1); NPM1 (1 transplanted in CR2); FLT3 (1). 2/17 had received Ven+HMA prior to SCT; 4 patients received HMA alone prior to SCT. 11 patients (65%) were naïve to either Ven or HMA prior to relapse. Median time to relapse was 181 (44-851) days post-HSCT. 9 (53%) patients received Azacitidine+Ven and 8 (47%) received Decitabine+Ven. HMA+Ven was the first line of therapy post-HSCT relapse in 14 patients. 2 had donor lymphocyte infusion (DLI) after either MEC or dacogen but relapsed prior to Ven+HMA. 1 had IDH (2) inhibitor. Patients received median of 2 (1-10) cycles of HMA+Ven. Six (35%) patients achieved complete remission/complete remission with incomplete hematologic recovery (CR/CRi), and 2/6 patients had negative measurable residual disease by multiparameter flow cytometry. Median overall survival was 361 days from relapse (Figure 1). 3/14 patients received subsequent DLI with Ven+HMA. Disease progression was the most common cause of death in 8/9 of patients who died during the follow up period. Most common side effects included neutropenic fever (n=8, 47%) and acute graft versus host disease (aGVHD) (n=5, 30%). 2/5 developed new aGVHD on HMA+Ven with no prior history of aGVHD. However, aGVHD was mainly grade I-II and responsive to therapy. Discussion HMA+Venetoclax demonstrates potential activity in patients with AML relapse post-HSCT with a CR/CRi rate of 35%, comparable to other salvage therapies. There were no unexpected side effect in this high-risk population. Larger studies are needed to confirm efficacy and toxicity in this setting. Disclosures McGuirk: Pluristem Ltd: Research Funding; Kite Pharmaceuticals: Consultancy, Honoraria, Research Funding, Speakers Bureau; Gamida Cell: Research Funding; Bellicum Pharmaceutical: Research Funding; Allo Vir: Consultancy, Honoraria, Research Funding; Juno Therapeutics: Consultancy, Honoraria, Research Funding; Astellas: Research Funding; Fresenius Biotech: Research Funding; Novartis: Research Funding. Lin:Aptevo: Research Funding; Abbvie: Research Funding; Bio-Path Holdings: Research Funding; Celgene: Research Funding; Gilead Sciences: Research Funding; Incyte: Research Funding; Jazz: Research Funding; Mateon Therapeutics: Research Funding; Ono Pharmaceutical: Research Funding; Pfizer: Research Funding; Prescient Therapeutics: Research Funding; Seattle Genetics: Research Funding; Tolero Pharmaceuticals: Research Funding; Trovagene: Research Funding; Genetech-Roche: Research Funding; Celyad: Research Funding; Astellas Pharma: Research Funding.

Salvage Therapy with Low-Dose Ruxolitinib Led to a Significant Improvement in Bronchiolitis Obliterans Syndrome in Patients with cGvHD after Allogeneic Hematopoietic Stem Cell Transplantation

Background Bronchiolitis obliterans syndrome (BOS) is a life-threatening pulmonary manifestation of chronic graft versus host disease (cGVHD) post-allogeneic hematopoietic stem cell transplantation (HSCT), without a clear standard of care. Systemic corticosteroids remain the backbone of therapy for BOS, but their side effect profile makes them disadvantageous for prolonged use. Ruxolitinib (RUXO), a Janus-associated kinase (JAK) 1/2 inhibitor approved for the treatment of patients with intermediate-2 or high-risk primary myelofibrosis,has shown excellent response rates in steroid-refractory/intolerant cGVHD. This study seeks to investigate the efficacy of ruxolitinib on steroid-refractory BOS, and additionally, determine the efficacy of ruxolitinib in these patients and the clinical factors affecting the response to ruxolitinib. Method This study involved adult patients suffering BOS after an allogeneic HSCT for a hematological malignancy between January 2014 and June 2018 at the First Affiliated Hospital of Zhejiang University School of Medicine and Ningbo Hospital of Zhejiang. Univariable analyses for treatment response risk factors were performed using the Fisher exact test and chi-square test. Logistic regression analysis was used to perform multivariable analysis to calculate the hazard ratio (HR) with a 95% confidence interval (CI). Overall survival (OS) was defined as the time from stem cell infusion to death from any cause and calculated by the Kaplan-Meier method. Results Twenty-five patients were retrospectively enrolled in this analysis and patient characteristics were shown in Table 1. At the time of BOS diagnosis, most patients presented with moderate or severe obstruction. Besides, all patients had worsening lung function or worsening clinical symptoms under systemic prednisone treatment. After a median duration of RUXO therapy of 8.5 (1.5-20) months, the overall response rate was 68.0%: two patients (8.0%) achieved complete remission, and 15 (60.0%) achieved partial remission. The median time from initiation of RUXO to achieve the best responses was 3 months (range, 1.5-8). Since initiating RUXO, predicted forced expiratory volume in 1 s (FEV1) % increased after 3 months and 6 months compared with measurements before RUXO in responders. Of note, an average reduction in prednisone dose of 39.3% after 3 months of ruxolitinib therapy and 59.5% after 6 months of ruxolitinib therapy was reported. Only FEV1 mild decline before ruxolitinib with a ratio ≤15% was an independent predictor to achieve a response to RUXO (HR = 0.063, 95% CI 0.006-0.624, P = 0.018). As for safety profile, hematological adverse effect included that two patients harboring cytopenia with grade 2-3. Regarding the nonhematological toxicities, two patients developed grade 3 hypertriglyceridemia. Referring to infection events, 11 patients (44%) had a severe pulmonary infection of ≥3 grade. Of note, cytomegalovirus (CMV) DNAemia was observed in 3 patients (12%) and Epstein-Barr virus (EBV) DNAemia was observed in 10 patients (40%). Following a median follow-up of 255 days after RUXO, the 2-year incidence of nonrelapse mortality and 2-year overall survival rate after RUXO among patients with BOS was 27.8% and 62.6%, respectively. Conclusion The present study showed that in heavily pretreated patients with BOS, ruxolitinib induced a relatively high response, leading to an increased 2-year OS rate in patients with BOS. Although a small number of subjects and a retrospective nonrandomized design of this study might make a bias, our data still indicated RUXO as a promising treatment option to improve the prognosis of post-HSCT BOS, with pulmonary function stabilization or even improvement and steroid sparing. Also, the substantial clinical benefits and efficacy of ruxolitinib on BOS need to be balanced against infection risks. Disclosures No relevant conflicts of interest to declare. OffLabel Disclosure: Ruxolitinib (RUX, Jakafi, Novartis, Basel, Switzerland)

Allogenic stem cell transplant-associated acute graft versus host disease: a computational drug discovery text mining approach using oral and gut microbiome signatures.

Acute graft versus host disease (aGVHD) is a major cause of non-relapse morbidity and mortality post-allogenic hematopoietic stem cell transplant (HSCT). Using conventional literature search and computational approaches, our objective was to identify oral and gut bacterial species associated with aGVHD, potentially affecting drug treatment via lipopolysaccharide (LPS) pathways. Medline, PubMed, PubMed Central, and Google Scholar were searched using MeSH terms. The top 100 hits per database were curated, and 25 research articles were selected to examine oral and gut microbiomes associated with health, HSCT, and aGVHD. Literature search validation, aGVHD drug targets, and microbial metabolic pathway identification were completed using BioReader, MACADAM, KEGG, and STRING programs. Our review determined that (1) oral genera Rothia, Solobacterium, and Veillonella were identified in HSCT patients' stool and associated with aGVHD; (2) shifts in gut enterococci profiles were determined in HSCT-associated aGVHD; (3) gut microbiome dysbiosis prior or during HSCT and lower Shannon diversity index at time of HSCT were also associated with increased risk of aGVHD and transplant related death; and (4) Coriobacteriaceae family was negatively correlated with gut aGVHD, whereas Eubacterium limosum was associated with decreased risk of chronic GVHD relapse. Additionally, we identified molecular pathways related to TLR4/ LPS, including candidate aGVHD drug targets, impacted by oral and gut bacterial taxa. Reduced microbial diversity reflects higher severity and mortality rate in HSCT patients with aGVHD. Multi-omics approaches to decipher oral and gut microbiome associations will be critical for developing aGVHD preventive therapies.

Clinical prevalence and outcome of cardiovascular events in the first 100 days postallogeneic hematopoietic stem cell transplant.

Recent advances in allogeneic hematopoietic stem cell transplant (HSCT) have allowed us to offer HSCT to older, advanced disease patients with more co-morbidities. Cardiovascular toxicity post-transplant is a major concern due to the increased risk of mortality. Few studies have examined the prevalence of CV events including CAD (MI, angina, PCI, CABG, CHF, arrhythmias), HTN, stroke/TIA, and death in the first 100days post-transplant. We assessed the impact of pretransplant MUGA results in predicting postallogeneic HSCT CV events and overall survival in the first 100days, and whether or not transient anthracycline-induced cardiomyopathy or cumulative anthracycline dose affected overall survival. This retrospective, cohort study included 665 patients with a median age of 52years who underwent HSCT from 2009 to 2015. The most frequent CV event in the first 100days post-HSCT was arrhythmia seen in 2.9% of patients followed up by CHF (12.3%), MI (9%), and angina (8%). Two patients had PCI, and both survived the first 100days. Cardiovascular risk factors predict for a poor MUGA scan but not survival. Higher dose anthracycline pretransplant predicted for a poor outcome. A history of CV disease, MI, or CAD was the most important predictive of CV events, P-value=.00002. 88.6% survived the first 100days. Patients with an EF<50% had a significant likelihood of having a CV event compared to patients with an EF>60% (OR=5.3, 95% CI [1.6-18.1], P=.0219). Cumulative anthracycline dose did not have a significant impact on overall survival.

Fear of cancer recurrence following allogeneic haematopoietic stem cell transplantation (HSCT) for haematological malignancy: A cross-sectional study.

The aim of this study was to quantify the prevalence of Fear of Cancer Recurrence (FCR) in patients with a prior haematology malignancy surviving more than one year post allogeneic haematopoietic stem cell transplantation (HSCT), and to identify the demographic, medical and psychological factors associated with FCR occurrence. Participants were adult allogeneic HSCT recipients who had undergone the procedure for acute leukaemia or other haematological malignancy between the years 2000-2012 in Sydney, Australia. They completed a purpose designed survey and six other validated instruments which assessed FCR, psychological functioning, quality of life, demographic, social and clinical variables. Of the 364 respondents, approximately 11% of the sample lived with severe FCR while only 5% of subjects reported having no FCR. Variables significantly associated with higher FCR included unemployment, a shorter time (years) post-transplant, not attending to health screening (PAP smear), a secondary diagnosis of skin cancer, younger age, referral to a psychiatrist and taking psychotropic medication. Higher psychological distress (depression, anxiety, stress) and lower quality of life made a significant contribution to the prediction of FCR. Post HSCT follow-up care should include an assessment and discussion regarding FCR to balance both realistic and unrealistic cancer recurrence risks. Managing FCR is one of the most ubiquitous unmet needs of survivors of haematological disease and it is important that HSCT nurses are both aware of the fear, and are equipped with knowledge on how to help patients navigate it with realistic expectations.

Study protocol of a pilot study evaluating feasibility and acceptability of a psychosexual intervention for couples postallogeneic haematopoietic stem cell transplantation

IntroductionSexual dysfunction is one of the most common side effects of allogeneic haematopoietic stem cell transplantation (HSCT) for haematological cancers. Problems can persist between 5 and 10 years post-transplant and...

Unmanipulated Stem Cell Boost for Mixed Chimerism in Transfusion Dependent Thalassemia.

Early mixed chimerism (MC) can lead to secondary graft rejection post allogeneic hematopoietic stem cell transplantation in transfusion dependent thalassemia (TDT) patients. Reduction of immunosuppression and donor lymphocyte infusions is the mainstay for treating MC. We report our experience of administering unmanipulated stem cell boost (SCB) in reversing progressive early MC. There were 70 transplants done for 69 TDT patients at our center between September 2005 and January 2020. Mixed chimerism was defined by > 5% recipient cells and the severity was assigned according to the proportion of recipient cells as level 1 = < 10%, level 2 = 10-25%, level 3 = > 25%. For patients developing MC level 2 and 3, we administered unmanipulated SCB and analyzed its safety and efficacy. Out of 70 transplants 7 (10%) had MC level 2 (3/7) and 3 (4/7). These patients received unmanipulated SCB at a median CD34 cell dose of 4.5 × 106/kg (range-3.5 × 106/kg-5.5 × 106/kg). Overall Response (stable MC and/or transfusion independency) to unmanipulated SCB was seen in 5 patients (71.4%). Five patients (71.4%) developed acute graft versus host disease (GVHD) of which 1 patient expired due to severe GVHD. SCB infusion was well tolerated by majority of our patients. The 3year overall survival and thalassemia free survival was 85.7% (6/7) and 57.1% (4/7) respectively. Timely monitoring of chimerism is important for detecting early MC. Development of acute GVHD is common after administration of unmanipulated SCB and requires vigilance and prompt management. Unmanipulated SCB is a feasible modality for treating progressive MC and salvaging the graft especially in resource-constrained settings.

Optimal pre-emptive cytomegalovirus therapy threshold in a patient population with high prevalence of seropositive status

IntroductionPreemptive therapy (PET) for cytomegalovirus (CMV) reactivation post allogeneic hematopoietic stem cell transplantation (SCT) was shown to decrease the incidence of CMV disease. However, the optimal PET threshold is elusive. Purpose of the studyTo examine the efficacy of PET initiation at a viral threshold of 1000 copies/mL (1560 IU/mL) in a patient population with high prevalence of CMV seropositive status. Patients and methodsA single center retrospective review of patients that underwent allogeneic SCT was done. ResultsA total of 195 allogeneic SCT recipients were included with median follow up of 18.1 (0.7–95.6) months. A total of 178 (91 %) of patients had a positive CMV PCR with median days to initial reactivation post SCT of 17 (1−1187); 129 patients had peak CMV titer < 1000 copies/mL (low titer) whereas the remaining 49 patients had a peak titer ≥ 1000 copies/mL (high titer). 120 (93 %) of patients with low titers cleared spontaneously with median time to clearance of 40 days (4−188). One patient in the high titer group developed CMV disease. At multivariable analysis; age at SCT HR 1.02 (1.004−1.04; 0.017), malignant vs. benign condition HR 9.4 (2.47−61; 0.0005) and cGVHD HR 0.37 (0.2−0.65; 0.0005) were significant for OS. ConclusionsCMV reactivation post SCT was very common in patients with high prevalence of seropositive status. A PET threshold of 1000 copies/mL (1560 IU/mL) appears desirable as it was associated with spontaneous clearance in over 90 % of patients while minimizing treatment related toxicity. Validation of these observations is warranted.

Identification and generation of tumor antigen-specific T cells directed against AML

Background & Aim Acute myeloid leukemia (AML) is an aggressive hematological malignancy characterized by aberrant expression of leukemia associated antigens (LAA) that can be presented in context of HLA molecules, to elicit anti-tumor T cell response and improve clinical outcomes. This study aimed to 1) identify targets of endogenous LAA-specific T cells in AML patients post allogeneic hematopoietic stem cell transplant (allo-HSCT) and whose detection was associated with favorable clinical outcomes and 2) assess the feasibility of generating LAA-specific T cells targeting these antigens for adoptive immunotherapy. Methods, Results & Conclusion We obtained blood from patients (n=8) with relapsed and/or refractory AML who were in remission post allo-HCST, and measured the frequency of T cells reactive against known LAAs (e.g. WT1, CCNA1, survivin, PRAME). These patients were followed for 1 year post-sampling. Of the tested antigens, we identified that the best predictor of those who would eventually relapse was the magnitude CCNA1-directed T cell activity (clinical remission vs relapse: 171 vs 7.13 mean spot forming colonies/1 × 10e5; p=0.03). We next hypothesized that outcomes for AML could be improved by the ex vivo preparation and adoptive transfer of stem cell donor-derived CCNA1-specific T cells to patients at risk of relapse post allo-HSCT. Thus, we exposed autologous peripheral blood mononuclear cells from healthy donors (n=14) with CCNA1 pepmix and were able to induce specific responses in 13 of 14 donors tested. The cultures expressed both central (30±3%) and memory markers (30±6%) and were polyclonal though the dominant CCNA1-directed response was CD8-mediated. Reactive cells were polyfunctional (dual IFNg+/TNFa+ secretion), and capable of lysing HLA-matched CCNA1+ myeloid leukemia cell lines and primary AML blasts, while CCNA1 negative and/or HLA mismatched targets were spared (mean±SEM %lysis =42.6±10 vs 4.3±1.7; p=0.03) Thus, by measuring endogenous immune activity and correlating this data with clinical outcomes we identify clinically relevant target antigens that may be suitable for future T cell therapy studies in AML. As a proof of principle, this study demonstrated the importance of CCNA1-targeted T cells and established the preclinical feasibility of expanding Th1-polarized reactive cells from healthy donors that are suitable for adoptive transfer. Our future studies involve identification of other novel targets in AML including neoantigens and clinical translation of these findings.

An Educational Initiative to Increase Bone Marrow Transplant Staff Knowledge of Steroid Induced Hyperglycemia Secondary to Graft Versus Host Disease Treatment

Topic Significance & Study Purpose/Background/Rationale Patients status post allogeneic hematopoietic stem cell transplant (HSCT) are at increased risk of developing graft versus host disease (GVHD). First-line treatment of GVHD is systemic high-dose steroids. Although effective, a major side effect of this treatment is hyperglycemia. Detection is often delayed, especially when treatment occurs in the outpatient setting. Methods, Intervention, & Analysis This educational study included baseline assessment of staff knowledge of recognition and treatment of steroid induced hyperglycemia, staff education on steroid induced hyperglycemia, and re-assessment of effectiveness of education and knowledge retention following education. Approximately 30 registered nurses (RNs) and nurse practitioners (NPs) were included in the survey. The baseline and post-education assessment contained 14 questions. Prior to education, the average overall score of the baseline assessment was 65.88%. The lowest scoring concepts included dosage of high-dose steroids, resolution of steroid induced hyperglycemia, testing for steroid induced hyperglycemia, effects of hyperglycemia related to steroid use, and incidence of steroid induced hyperglycemia. The overall average score on the post-test was 75.5%, with areas of most improvement including when to test for steroid induced hyperglycemia, steroid dosage considered high-dose, steroid peak times with associated increase in blood glucose, and steroid preparations most likely to cause increase in blood glucose. Findings & Interpretation and Discussion & Implications A 1-month post educational assessment to determine educational effectiveness and staff retention concluded that education was effective. A knowledge deficit in the recognition and treatment among RNs and NPs was identified that will likely improve with continued staff education. Now that the knowledge deficit has been identified, additional education regarding steroid induced hyperglycemia will be implemented to include updates for patient education.

Role of Post-Allogeneic Hematopoietic Stem Cell Transplantation Low-Dose Azacitidine for Prevention of Relapse in Patients with Acute Myeloid Leukemia and Myelodysplastic Syndrome: A Retrospective Analysis

Introduction Relapse after allogeneic hematopoietic stem cell transplantation (HSCT) for acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) remains a major cause of treatment failure with associated poor prognosis. Low-dose post-HSCT maintenance azacitidine (AZA) has proved to be beneficial in preventing relapses (de Lima et al. Cancer 2010). Herein, we retrospectively evaluated outcomes of patients (pts) treated with low-dose AZA post-HSCT. Methods Pts with AML and MDS who underwent allogeneic HSCT between 2012-2018 at two centers were evaluated and categorized into AZA group (with low-dose AZA maintenance) and control group (without AZA maintenance). In control group, pts who died or relapsed prior to day +100, had grade III-IV aGVHD or received maintenance therapy other than AZA (e.g. FLT3 inhibitors) were excluded. Using Kaplan-Meier method, event (defined as relapse or death) free survival (EFS) and overall survival (OS) were computed and compared using log-rank test. Results A total of 107 patients were included; 53 (49.5%) in AZA and 54 (50.5%) in control groups. Disease and transplant-related characteristics are shown in table 1. Both groups were comparable with respect to age, diagnosis, disease risk stratification, disease status at HSCT, and MRD status at day +30 and day +100 (table 1). More pts received reduced intensity conditioning (RIC) in the AZA group (71.6% vs 37%, p= Conclusions In our cohort, low-dose AZA maintenance was generally well tolerated. The results of this study indicate that AZA maintenance is feasible and associated with improved EFS and OS. In addition, AZA has the potential of improving relapse rates even in pts who are unable to receive myeloablative conditioning as a significant number of pts in AZA group in this study received RIC. The optimal timing, duration of treatment and selection of pts most suitable for AZA for maximum benefit, however, requires further studies.

Chimerism Monitoring with Highly Sensitive and Precise Next-Generation Sequencing Assay in Patients Post-Allogeneic Hematopoietic Stem Cell Transplantation

<h3>Introduction</h3> Chimerism testing of peripheral blood and bone marrow aspirates following allogeneic hematopoietic cell transplantation (HCT) is important to evaluate engraftment kinetics and potentially early detection of disease relapse¹. NGS-based chimerism assays use SNP panels and provide standardized workflow with automated data analyses. <h3>Objectives</h3> We aim to evaluate performance of an NGS-based chimerism assay and compare it to existing laboratory method based on Short Tandem Repeat (STR) analysis. <h3>Methods</h3> Genomic DNA (gDNA) derived from PBMCs of unrelated donors were mixed at fractions ranging from 0.1% - 50% to evaluate sensitivity and specificity of the NGS-based chimerism assay in artificial genomic chimeras. 3-10 ng gDNA was used to prepare libraries with the assay kit and sequenced on Illumina MiSeq. <h3>Results</h3> Linear regression analyses of gDNA fractions (expected, observed) detected a linear signal at a minimum of 0.1% of minor gDNA in a two-gDNA chimeric mix (R²=1, average CV = 4.5%, range = 0.2-12.4). Chimeric samples with three distinct gDNAs gave linear signal as low as 0.5% of minor gDNA fraction (CV < 2%, range = 0.01-5.5%), a scenario that is clinically relevant in double-cord HCT or second HCT from different donors. The NGS-based chimerism assay was also tested on post-transplant samples derived from three HCT recipients. Results were compared longitudinally and between the two test methods at various time points (days) post transplantation. While majority results were consistent with previous data from STR, some discrepancies were observed. Patient 1, day+128, showed microchimerism (0.1%) that was undetected by STR (0%). Patient 2, day+287, showed low level (2.42%) of recipient DNA while STR reported full donor engraftment. Such clinical cases underscore the need for high sensitivity assays to more accurately quantitate donor-recipient fractions in post-HCT samples. <h3>Conclusions</h3> Using the test NGS-based chimerism assay on two and three gDNA mixes, we observe 10X greater sensitivity of minor fraction quantitation compared to current STR method. In our experience, high sensitivity, precision over a wide range of detection and robust performance with low input DNA may qualify this NGS-based chimerism assay as a potential method of choice for routine engraftment monitoring and potential early detection of disease relapse.

Disease Progression, Hospital Readmissions, and Clinical Outcomes of Patients with Steroid-Refractory Acute Graft-Versus-Host Disease: A Multicenter Chart Review

Background: Acute graft-versus-host disease (aGVHD) post allogeneic hematopoietic stem cell transplantation (HCT) has a significant impact on morbidity and mortality. The standard first-line therapy for grade II-IV aGVHD is systemic corticosteroids (CS), which provide effective control in 40%-60% of patients. Patients may be unable to taper steroids due to new organ involvement or aGVHD flares. The objective of this retrospective multicenter study was to describe the clinical course, outcomes, and hospital readmissions for patients with aGVHD who were refractory to or dependent on systemic CS. Methods: A multicenter retrospective chart review was conducted at 11 large US academic and community transplant centers to identify patients who had their first HCT between Jan 1, 2014, and June 30, 2016, and subsequently developed grade II-IV aGVHD (defined by International Bone Marrow Transplant Registry Severity Index). Patients who participated in a GVHD prophylaxis trial or used Janus kinase inhibitors were excluded. Steroid dependence (SD)/steroid refractory (SR) was defined as the use of additional systemic anti-GVHD therapy, inability to taper high-dose steroids (≥1 mg/kg) by ≥25%, or tapering of CS dose by ≥25% but not &lt;10 mg/day. Clinical outcomes included changes in aGVHD grade or organs involved, aGVHD reoccurrence, and all-cause mortality. Results: Patient (N=168) mean age was 55 years, and 64% were male. The stem cell source was peripheral blood for 74% of patients. Median time from transplant to aGVHD diagnosis was 30 days (interquartile range [IQR]: 21-49). At the time of aGVHD diagnosis, most patients had grade I or II (65%; Figure 1) disease: 39% had skin involvement only; 38% had lower gastrointestinal (GI) involvement; and 37% had ≥2 organs involved (Figure 2). At the time of maximum aGVHD grade, most patients (66%) had grade III-IV disease: 25% had skin involvement only; 54% of patients had lower GI involvement; and 54% had ≥2 organs involved. Between the time of diagnosis and maximum aGVHD grade, 54% of patients had new organ involvement or an increase in aGVHD grade. Median time from diagnosis to maximum grade was 6.0 days. Of the 146 patients with grade II-IV aGVHD at diagnosis, 82% (119/146) were given systemic CS as first-line therapy, and 49% (72/146) initiated systemic CS on the day of diagnosis. Among the 119 patients, the average starting daily dose was 77 mg (0.9 mg/kg) for prednisone and 166 mg (1.8 mg/kg) for methylprednisolone. During follow-up (median 194 days from aGVHD diagnosis to death/last visit, IQR: 58-720), 36% of patients had an increase in steroid dose, and 88% were unable to taper below 10 mg/day. aGVHD recurred in 42% of patients (70/168) and was managed by increasing the CS dose in 79% of these patients. Over half of patients (53%; 89/168) received additional systemic anti-GVHD therapy; of those, 41% had an increase in CS dose before receiving additional therapy. Median time from CS initiation to additional therapy was 21 days. Frequently used additional therapies included sirolimus (19%), polyclonal antibodies (antithymocyte globulin/antilymphocyte globulin; 18%), mycophenolate mofetil (17%), tocilizumab (16%), extracorporeal photopheresis, and etanercept (both 13%). 26% (23/89) used ≥2 additional therapies. Overall, 57% of patients (95/168) required hospital readmission(s); 24% had ≥2 readmissions within 100 days post-HCT, with a mean inpatient length of stay of 50 days. Half (51%) of patients experienced an infection within the first 100 days post-HCT. Relapse of the underlying malignancy was reported in 35 patients (21%). Overall, 70% of patients (118/168) died at a median of 118 days (IQR: 62.0-234.1) from aGVHD diagnosis; 82% of patients with aGVHD progression died at a median of 116.0 days (IQR: 49-223), and 80% of patients with maximum grade III-IV aGVHD died at a median of 80 days (IQR: 42-216). Additionally, 86% of patients with lower GI aGVHD died at a median of 74.0 days (IQR: 44-174) (Figure 3). Conclusions: The majority of patients with aGVHD had severe and rapidly progressing disease. These findings indicate that clinical outcomes were poor among patients with SR and SD, with a mortality rate of 70% within 4 months of aGVHD diagnosis. Most patients required hospital readmission with an extended length of stay. The rapidly worsening clinical course further emphasizes the need for effective and tolerable therapies that prevent or reverse disease progression. Disclosures Yu: Incyte: Employment, Equity Ownership. Hanna:Asclepius Analytics: Employment. Paranagama:Incyte: Employment, Equity Ownership. Tang:Asclepius Analytics: Employment. Naim:Incyte: Employment, Equity Ownership. Galvin:Incyte: Consultancy.

Autophagy in Endothelial Cells Regulates Their Hematopoiesis Supporting Ability

Background: Endothelial cells(ECs) serve as an instructive platform to support hematopoietic stem cells(HSCs) for homeostasis, however the underlying mechanism by which ECs regulate HSCs remains unclear. In humans, poor graft function(PGF) is characterized by pancytopenia post allogeneic hematopoietic stem cell transplantation(allo-HSCT) and serves as an appropriate model to study hematopoiesis in real world. Our series of studies reported that the impaired BM ECs are responsible for defective hematopoiesis post allo-HSCT(2013 BBMT, 2014 BBMT, 2015 BMT, 2016 Blood, 2018 AJH, 2019 Blood Advances), whereas prophylactic strategies to improve BM ECs promote hematopoietic reconstitution post allo-HSCT(2019 Blood Advances), further indicating the critical role of BM ECs in regulating HSCs. Autophagy, an essential homeostatic process responsible for nutrient deprivation, can be activated as cytoprotective response. Conversely, over-activated autophagy contributes to cancer progression. Beclin-1, an autophagy-related protein, plays a critical role in the formation of autophagosomes. Accumulating evidence has demonstrated the essential roles of ECs in supporting HSCs and of autophagy in benefiting ECs, raising the question of whether EC autophagy plays a critical role in supporting HSCs. Moreover, the effect of EC autophagy on HSC support needs to be elucidated and validated in a human pancytopenia disease model. Aims: The current study was performed to investigate whether the autophagy status in ECs regulates their ability to support hematopoiesis. Moreover, we evaluated the effect of EC autophagy on HSC support in PGF patients, and the results may provide a promising therapeutic target for PGF patients post allo-HSCT. Methods: Human Umbilical Vein Endothelial Cells(HUVECs) were genetically knockdown or overexpressed of Beclin-1. RNA-seq analyses were performed to elucidate the regulatory mechanism underlying hematopoietic supporting ability of HUVECs, which were further confirmed by qRT-PCR. In vitro pharmacologic regulations of autophagy(Rapamycin, an autophagy activator, and Hydroxychloroquine, an autophagy inhibitor) were administrated to HUVECs. Subsequently, a prospective case-control study was conducted. The levels of autophagy-related markers(LC3, Beclin1, and p62), and intracellular autophagosomes in BM ECs from PGF patients and their matched good graft function(GGF) patients were evaluated by monodansylcadaverine(MDC) staining, flow cytometry, western blot and transmission electron microscopy. HUVECs or BM ECs from PGF patients were cocultured with normal CD34+ cells. The quantity and function, especially the HSCs supporting ability of HUVECs or BM ECs from PGF patients were evaluated by colony-forming unit assay after Rapamycin treatment. Results: Inhibiting autophagy by Beclin-1 knockdown significantly reduced the hematopoiesis-supporting ability of HUVECs, which could be restored by activating autophagy through up-regulating Beclin-1. During the above process, autophagy positively regulated hematopoiesis-regulating genes in HUVECs. In addition, in vitro pharmacologic regulations of autophagy by Rapamycin or Hydroxychloroquine could modulate the hematopoietic supporting ability of HUVECs through regulating autophagy. Moreover, genetic and pharmacologic down-regulating autophagy in HUVECs impaired their quantity and function, which could be restored by up-regulating autophagy in HUVECs. Subsequently, the prospective case-control study demonstrated that defective autophagy, reduced Beclin-1 expression and deficient CFU plating efficiency in BM ECs from PGF patients when compared to their matched GGF patients. Importantly, Rapamycin quantitatively and functionally improved the impaired BM ECs from PGF patients in vitro, and especially enhanced their ability to support HSCs by activating the defective autophagy. Summary / Conclusions: Our results suggest that the autophagy status of ECs modulates their ability to support hematopoiesis by regulating the Beclin-1 pathway. Defective autophagy in BM ECs may be involved in the pathogenesis of PGF post allo-HSCT. Although further validation is required, our data suggest that Rapamycin could improve the impaired HSC-supporting ability of ECs by activating autophagy, thus providing a promising therapeutic approach for PGF patients. Disclosures No relevant conflicts of interest to declare.

Single-Cell RNA-Seq Identifies Potentially Pathogenic B Cell Populations That Uniquely Circulate in Patients with Chronic Gvhd

While B cells are known to contribute to the pathogenesis of chronic graft-versus-host disease (cGVHD) in mice, it has been challenging to elucidate intrinsic mechanisms of tolerance loss in patients. To identify distinct and potentially targetable B-cell subsets in cGVHD, we employed single-cell RNA-Seq along with an unsupervised hierarchical clustering analysis, targeting 10,000 single B cells from each of eight patients who were &amp;gt;12 months post-allogeneic hematopoietic stem cell transplantation (HCT) and either had active cGVHD manifestations (n=4) or never developed cGVHD (n=4). Bioinformatics analysis of pooled cell data (using R with Seurat extension package) identified 6 major B cell clusters common to all patients (Figure 1A). "Intra-cluster" gene comparison (using R package DESeq2, false-discovery rate 0.05) revealed numerous differentially expressed genes between patient groups. The greatest number of differentially-expressed genes occurred in a cluster referred to herein as 'Cluster 6' (Figure 1A, in yellow with asterisk). Within Cluster 6, B cells from active cGVHD patients expressed significantly increased ITGAX (CD11c, Padj =0.007), TNFRSF13B (TACI, a receptor for BAFF, Padj =0.003), IGHG1 (IgG1, Padj =9.3e-06) and IGHG3 (IgG3, Padj =1.7e-12), along with 44 additional genes (to be discussed). Thus, Cluster 6 in cGVHD patients may represent a CD11cpos, BAFF-responsive B cell subset primed to undergo isotype switching in response to alloantigen. Flow cytometry analysis on PBMCs from an independent HCT patient cohort (n=10) confirmed that CD11cpos B cells were indeed significantly expanded in cGVHD (P &amp;lt; 0.01, Figure 1B), and revealed these B cells were also TACIpos, CD19high, forward scatter high (FSChigh) blast-like cells (Figure 1C). We found that these CD11cpos B cells had mixed expression of CD21, CD27, IgD and CD24 (Figure 1C). Remarkably, other recent studies on bulk patient B cells have suggested that similar CD11cposCD21negCD19highT-BETpos cells are critical drivers of humoral autoimmunity in diseases including systemic lupus erythematosus (SLE; Scharer et al. 2019; Rubtsova et al. 2017; Rubtsov et al. 2011). This subset now identified by single-cell RNA-Seq is consistent with a population of TACIhigh B cells that produced IgG in response to BAFF treatment ex vivo (Sarantopoulos 2009). Data suggest we have identified functionally distinct and potentially targetable B cell subpopulations. We are employing functional assays to determine whether the additional molecular pathways now elucidated account for our previous work showing greater ex vivo B cell survival rates and hyper-responsiveness to surrogate antigen (Allen et al. 2012, 2014), certain TLR agonists (Suthers et al. 2017), and NOTCH ligand (Poe et al. 2017). In addition to more deeply characterizing B-cell subsets in cGVHD, our single-cell RNA-Seq analyses identified several genes significantly altered across multiple B cell clusters in the cGVHD group, implicating more broad alterations of some genes in this disease. Among these is CKS2, a critical cell cycle regulator, which was significantly increased in cGVHD B cells (Padj 1.0e-10 to 0.018, depending on the cluster evaluated). Increased CKS2 expression was validated by qPCR analysis on B cells from a separate HCT patient cohort with or without cGVHD (P &amp;lt; 0.001, Figure 1D), suggesting that the majority of cGVHD B cells are primed to enter the cell cycle at multiple stages of differentiation when exposed to the proper stimuli. In summary, we used an unbiased approach to identify and further characterize an extrafollicular CD11cposTACIposCD19high B cell population in cGVHD patients that appears to be activated and undergoing active IgG isotype switching. This plasmablast-like B cell population is potentially amenable to therapeutic intervention to prevent pathogenic antibody production. Importantly, we also identify gene alterations across the cGVHD peripheral B cell compartment that potentially underpin promotion of hyperactivated B cells in this disease. Therapeutic strategies to target these pathways will also be discussed. This work was supported by a National Institutes of Health grant, R01HL129061. Disclosures Ho: Omeros Corporation: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Research Funding; Jazz Pharmaceuticals: Consultancy. Horwitz:Abbvie Inc: Membership on an entity's Board of Directors or advisory committees. Rizzieri:Celgene, Gilead, Seattle Genetics, Stemline: Other: Speaker; AbbVie, Agios, AROG, Bayer, Celgene, Gilead, Jazz, Novartis, Pfizer, Sanofi, Seattle Genetics, Stemline, Teva: Other: Advisory Board; AROG, Bayer, Celgene, Celltron, Mustang, Pfizer, Seattle Genetics, Stemline: Consultancy; Stemline: Research Funding.

1088P - Impact of donor lymphocyte infusion in relapsing myeloid neoplasms post allogeneic hematopoietic stem cell transplantation

BackgroundDonor lymphocyte infusions (DLI) become one of the currently used approaches to treat post-transplant relapses. However, the wide use of the different DLI strategies, its effectivity and toxicity are still unpredictable in many patients. We evaluated the impact of DLI for patients with myeloid neoplasms experienced relapse post hematopoietic stem cell transplantation (HSCT). MethodsThis study included patients with myeloid neoplasms who received DLI post HSCT at the BMT unit, Children Cancer Hospital Egypt (CCHE-57357) from 2009 to 2017. DLI was given for patients with either rising minimal residual disease (MRD) or after systemic chemotherapy for those who experienced frank relapse. ResultsA total of 20 patients received post HSCT DLI were analyzed, with median age of 7 years. About 12 patients (60%) had acute myeloid leukemia (AML), 5 with chronic myeloid leukemia (CML) and 3 cases had myelodysplastic syndrome (MDS). Seven patients had frank relapse and given systemic chemotherapy followed by DLI upon complete remission, while 13 patients received only DLI due to rising MRD. Early relapse (during 1st year) was reported in 14 cases (70%) and 7 patients relapsed beyond 1st year post-transplant. Regarding the graft status at relapse, 15 patients had maintained complete chimera while 5 patients showed mixed chimera. The one-year disease free survival (DFS) and overall survival (OS) post DLI for the whole cohort were 54% and 64%, respectively with one patient had a non-relapse mortality and 6 patients developed graft versus host disease (GvHD) post DLI. According the initial diagnosis, DFS at one year was 80% for CML, 66% for MDS and 41% for AML patients. Also DFS was better for those with late relapse (70% vs 57% for early relapse) and for those who developed GvHD post DLI. ConclusionsDLI was associated with a durable efficacy and low toxicity in pediatric patients with hematologic malignancies. However, larger studies and standardized approaches are required to identify the outcome predictors of this treatment modality. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

Eltrombopag: Role in Cytopenias Following Hematopoietic Stem Cell Transplantation.

Eltrombopag is a small molecule oral agonist of the thrombopoietin receptor. Initially used for improving thrombocytopenia in chronic immune thrombocytopenia (ITP), it was later found to be efficacious in various other etiologies of thrombocytopenia as well as inherited marrow failure syndromes. Lately, it has been used for thrombocytopenia and poor graft function after allogeneic hematopoietic stem cell transplantation (HSCT) without any severe adverse events. Although prospective evidence of the efficacy is limited, there are increasing reports on the safety and efficacy with Eltrombopag in post HSCT thrombocytopenia and poor graft function. This provides an exciting opportunity for further research to evaluate both efficacy and cost-effectiveness of the use of Eltrombopag in this scenario. Here we review the current evidence on the indications for the use of Eltrombopag in the post allogeneic hematopoietic stem cell transplant setting.

Impact of cytomegalovirus complications on resource utilization and costs following hematopoietic stem cell transplant

Objective: The impact of cytomegalovirus (CMV) infection on healthcare resource utilization (HCRU) and costs post-allogeneic hematopoietic stem cell transplant (allo-HSCT) has not been well studied in the US. This retrospective, observational cohort study examined such outcomes in the first year following allo-HSCT.Methods: The IBM MarketScan administrative claims database was used to identify adults who underwent a first allo-HSCT between 1 January 2010 and 30 April 2015. Patients were required to have continuous medical and pharmacy enrollment for ≥12 months before and after the allo-HSCT. HCRU and medical costs (2016 US$) were compared by the presence or absence of CMV infection over 1-year follow-up.Results: A total of 1825 adults met the inclusion criteria (57.5% male; mean age 50.8 years). During the follow-up period, 410 (22.5%) patients had a CMV-related claim. Patients with CMV infection were significantly more likely to have a 60-day-(31.2 vs. 19.4%), 100-day-(50.0 vs. 30.5%) or 365-day readmission (78.0 vs. 57.8%) compared to those without a CMV-related event (all p < .001). During follow-up, patients with CMV infection had significantly greater mean total costs, reflecting higher inpatient costs ($677,240 vs. $462,562), outpatient costs ($141,366 vs. $94,312) and prescription drug costs ($27,391 vs. $22,082) (all p < .001). Valganciclovir (59.8%) and ganciclovir (33.7%) were the most commonly utilized anti-viral agents in patients with CMV.Conclusions: CMV infection was associated with significantly higher healthcare resource utilization and costs during the first year post-allo-HSCT. Additional research is warranted to further evaluate the consequences of post-HSCT CMV infection, as well as cost-effective measures to minimize its occurrence.

The clinical and economic burden of cytomegalovirus management post allogeneic hematopoietic stem cell transplantation in Japan – a retrospective database study

Introduction: Reactivation of cytomegalovirus (CMV) infection is a major threat and it causes significant morbidity and mortality after allogeneic hematopoietic stem cell transplantation (allo-HSCT). There remains, however, a paucity of evidence regarding the economic burden of current CMV management in Japan. The aim of this study is to characterize the healthcare resource utilization (HCRU) and cost incurred for CMV management post allo-HSCT, using a Japanese hospital claims database.Methods: Patients who underwent allo-HSCT between April 2010 and March 2018 were identified and followed up for 180 days.Results: In total, 916 patients were included for analysis and categorized into CMV (−) group and CMV (+) group based on the presence of a CMV episode within 100 days post allo-HSCT. A CMV episode was defined as evidence of receiving at least one dose of the following anti-CMV drugs, ganciclovir, foscarnet, or valganciclovir. The mean (± standard deviation [SD]) total length of stay was 93.6 (± 43.7) days in the CMV (+) group, which was significantly longer than 55.9 (±40.6) days in the CMV (−) group, and this trend was more pronounced in patients with multiple CMV episodes. The mean (±SD) total medical cost within 180 days post allo-HSCT was US$122,328 (±56,977) in the CMV (+) group, while the mean total medical cost was US$75,344 (±43,821) in the CMV (−) group. Moreover, transfusion and antimicrobial use was observed as the major medication cost component, which is suggestive of the indirect effect of CMV episodes.Conclusion: This study demonstrated that CMV episodes post allo-HSCT were associated with increased HCRU and cost.

Severe hemorrhagic cystitis caused by the BK polyomavirus is associated with decreased survival post-allogeneic hematopoietic stem cell transplantation.

BK polyomavirus reactivation can occur following allogeneic hematopoietic stem cell transplantation (allo-HSCT) and may lead to hemorrhagic cystitis (BKPyV-HC). We hypothesized that development of BKPyV-HC is associated with increased mortality post allo-HSCT. We retrospectively reviewed data on 133 adult patients (≥18years old) who underwent allo-HSCT from 2007 until 2014 at Hospital Israelita Albert Einstein in São Paulo, Brazil. Thirty-six patients presented with BKPyV-HC after a median time of 42days, with a 1-year cumulative incidence probability of 28.9% (95% CI 21.5%-36.7%). In a multivariate Cox model, risk factors for development of BKPyV-HC included younger age, male sex, development of grade 2-4 acute graft-versus-host disease and recipients of umbilical cord blood grafts. Development of grade 3-4 BKPyV-HC (but not grade 1-2) was associated with a decreased overall survival (OS) in a multivariate Cox model (hazard ratio [HR] 7.51, P<0.0001) and an increased risk of TRM (HR 3.66, P<0.0001). Grade 3-4 BKPyV-HC was also associated with an increased risk of relapse that did not reach statistical significance (HR 3.01, P=0.07). Median overall survival (OS) post-BKPyV-HC was 4.7months, and cidofovir had no impact on survival. Development of BKPyV-HC appears to be associated with decreased survival following allo-HSCT.