Myeloablative Hematopoietic Cell Transplantation Research Articles

Impact of dexamethasone on transplant-related mortality in pediatric patients: a multi-site, propensity score-weighted, retrospective assessment.

Dexamethasone use during hematopoietic cell transplant (HCT) conditioning varies between pediatric centers. This study aimed to estimate the difference in 1-year treatment-related mortality (TRM) between patients who did or did not receive dexamethasone during HCT conditioning. Secondary objectives were to estimate the difference between dexamethasone-exposed and dexamethasone-unexposed groups in 1-year event-free survival (EFS), time to neutrophil engraftment, acute graft-versus-host disease (aGVHD), and invasive fungal disease (IFD) at day + 100. This was a seven-site, international, retrospective cohort study. Patients < 18years old undergoing their first allogeneic or autologous myeloablative HCT for hematologic malignancy or aplastic anemia between January 1, 2012, and July 31, 2017, were included. To control for potential confounders, propensity score weighting was used to calculate the standardized mean difference for all endpoints. Among 242 patients, 140 received dexamethasone during HCT conditioning and 102 did not. TRM was unaffected by dexamethasone exposure (1.7%; 95% CI - 7.4, 10.2%). Between-group differences in secondary outcomes were small. However, dexamethasone exposure significantly increased possible, probable, and proven IFD incidence (9.0%, 95% CI 0.8, 17.3%). TRM is not increased in pediatric patients who receive dexamethasone during HCT conditioning. Clinicians should consider potential IFD risk when selecting chemotherapy-induced vomiting prophylaxis for pediatric HCT patients.

The impact of pre-transplant respiratory virus detection on post-transplant outcomes in children undergoing hematopoietic cell transplantation.

Pre-transplant respiratory virus (RV) infections have been associated with negative transplant outcomes in adult hematopoietic cell transplantation (HCT) recipients. In the era of HCT delay due to high-risk RVs, we examined the impact of pre-transplant RV detection on transplant outcomes in a pediatric HCT recipients. This retrospective cohort study included myeloablative allogeneic HCT recipients from 2010 to 2019. All patients were screened for RV at least once within 90 days before HCT using RT-PCR, regardless of symptoms. Post-transplant outcomes included days alive and out of hospital (DAOH) and progression to lower respiratory tract infection (LRTI). Among 310 patients, 134 had a RV detected in the 90 days prior to HCT. In univariable analysis, transplant factors including younger age, total body irradiation, umbilical cord blood transplantation, lymphocyte count less than 100/mm3, and HCT comorbidity index score ≥3, and viral factors including symptomatic infection, human rhinovirus (HRV) as a virus type, and symptomatic pre-transplant upper respiratory tract infection (URTI) were associated with fewer DAOH. In multivariable analysis, transplant factors remained significant, but not viral factors. There was a higher incidence of progression to post-transplant LRTI with the same pre-transplant RV if the last positive PCR before HCT was ≤30 days compared to >30 days (p=0.007). In the setting of recommending HCT delay for high-risk RVs, symptomatic URTI, including HRV infections, may lead to increased duration of hospitalization and early progression to LRTI when transplantation is performed within 30 days of the last positive PCR test.

42 Severe Combined Immunodeficiency Due To A Monoallelic ITPR3 Variant Presenting With Lymphohistiocytosis And Bone Marrow Failure Treated With Myeloablative Hematopoietic Cell Transplantation

42 Severe Combined Immunodeficiency Due To A Monoallelic ITPR3 Variant Presenting With Lymphohistiocytosis And Bone Marrow Failure Treated With Myeloablative Hematopoietic Cell Transplantation

Single-center randomized trial of T-reg graft alone vs T-reg graft plus tacrolimus for the prevention of acute GVHD

AbstractAllogeneic hematopoietic cell transplantation (HCT) is a curative therapy for hematological malignancies for which graft-versus-host disease (GVHD) remains a major complication. The use of donor T-regulatory cells (Tregs) to prevent GVHD appears promising, including in our previous evaluation of an engineered graft product (T-reg graft) consisting of the timed, sequential infusion of CD34+ hematopoietic stem cells and high-purity Tregs followed by conventional T cells. However, whether immunosuppressive prophylaxis can be removed from this protocol remains unclear. We report the results of the first stage of an open-label single-center phase 2 study (NCT01660607) investigating T-reg graft in myeloablative HCT of HLA-matched and 9/10-matched recipients. Twenty-four patients were randomized to receive T-reg graft alone (n = 12) or T-reg graft plus single-agent GVHD prophylaxis (n = 12) to determine whether T-reg graft alone was noninferior in preventing acute GVHD. All patients developed full-donor myeloid chimerism. Patients with T-reg graft alone vs with prophylaxis had incidences of grade 3 to 4 acute GVHD of 58% vs 8% (P = .005) and grade 3 to 4 of 17% vs 0% (P = .149), respectively. The incidence of moderate-to-severe chronic GVHD was 28% in the T-reg graft alone arm vs 0% with prophylaxis (P = .056). Among patients with T-reg graft and prophylaxis, CD4+ T-cell–to–Treg ratios were reduced after transplantation, gene expression profiles showed reduced CD4+ proliferation, and the achievement of full-donor T-cell chimerism was delayed. This study indicates that T-reg graft with single-agent tacrolimus is preferred over T-reg graft alone for the prevention of acute GVHD. This trial was registered at www.clinicaltrials.gov as #NCT01660607.

Tacrolimus/methotrexate vs tacrolimus/reduced-dose methotrexate/mycophenolate for graft-versus-host disease prevention

AbstractTacrolimus (Tac)/methotrexate (MTX) is standard graft-versus-host disease (GVHD) prophylaxis; however, is associated with several toxicities. Tac, reduced-dose MTX (mini-MTX), and mycophenolate mofetil (MMF) have been used but never compared with standard MTX. We performed a randomized trial comparing Tac/MTX (full-MTX) with Tac/mini-MTX/MMF (mini-MTX/MMF) for GVHD prevention after allogeneic hematopoietic cell transplantation (HCT). Patients (pts) receiving first myeloablative HCT using an 8/8 HLA-matched donor were eligible. Primary end points were incidence of acute GVHD (aGVHD), mucositis, and engraftment. Secondary end points included chronic GVHD (cGVHD), organ toxicity, infection, relapse, nonrelapse mortality (NRM), and overall survival (OS). Ninety-six pts were randomly assigned to full-MTX (N = 49) or mini-MTX (N = 47). The majority (86%) used bone marrow grafts. There was no significant difference in grade 2-4 aGVHD (28% mini-MTX/MMF vs 27% full-MTX; P = .41); however higher incidence of grade 3-4 aGVHD (13% vs 4%; P = .07) with mini-MTX/MMF. Pts receiving mini-MTX/MMF had lower grade 3 or 4 mucositis and faster engraftment. There were no differences in moderate-to-severe cGVHD at 1 year or infections. Pts receiving mini-MTX/MMF experienced less nephrotoxicity and respiratory failure. There was no difference in the 1-year relapse (19% vs 21%; P = .89) and OS (72% vs 71%; P = .08), and mini-MTX/MMF was associated with lower but nonsignificant NRM (11% vs 22%; P = .06). Compared with full-MTX, mini-MTX/MMF was associated with no difference in grade 2-4 aGVHD and a more favorable toxicity profile. The higher severe aGVHD warrants further study to optimize this regimen. The trial was registered at www.clinicaltrials.gov as #NCT01951885.

Phase II Study of Myeloablative 7-8/8-Matched Allotransplantation with Post-Transplantation Cyclophosphamide, Tacrolimus, and Mycophenolate Mofetil

Graft-versus-host disease (GVHD) is the major toxicity of allogeneic hematopoietic cell transplantation (HCT). We hypothesized that a GVHD prophylaxis regimen of post-transplantation cyclophosphamide (PTCy), tacrolimus (Tac), and mycophenolate mofetil (MMF) would be associated with incidences of acute and chronic GVHD in patients receiving a matched or single antigen mismatched HCT. This Phase II study was conducted at the University of Minnesota using a myeloablative regimen of either total body irradiation (TBI) at a total dose of 1320 cGy, administered in 165-cGy fractions, twice daily from day -4 to day -1, or busulfan (Bu) 3.2 mg/kg daily (cumulative area under the curve, 19,000 to 21,000 μmol/min/L) plus fludarabine (Flu) 40 mg/m2 once daily on days -5 to -2, followed by a GVHD prophylaxis regimen of PTCy 50 mg/kg on days +3 and +4, Tac, and MMF beginning on day +5. The primary endpoint was the cumulative incidence of chronic GVHD necessitating systemic immunosuppression (IST) at 1 year post-transplantation. Between March 2018 and May 2022, we enrolled 125 pediatric and adult patients, with a median follow-up of 813 days. The incidence of chronic GVHD necessitating systemic IST at 1 year was 5.5%. The rate of grade II-IV acute GVHD was 17.1%, and that of grade III-IV acute GVHD was 5.5%. Two-year overall survival was 73.7%, and 2-year graft-versus-host disease-free, relapse-free survival was 52.2%. The 2-year cumulative incidence of nonrelapse mortality was 10.2%, and the rate of relapse was 39.1%. There was no statistically significant difference in survival outcomes between recipients of matched donor transplants versus recipients of 7/8 matched donor transplants. Our data show that myeloablative HCT with PTCy/Tac/MMF results in an extremely low incidence of severe acute and chronic GVHD in well-matched allogeneic HCT.

Corticosteroids as graft-versus-host disease prophylaxis for allogeneic hematopoietic cell transplant recipients with calcineurin inhibitor intolerance

Background aimsAlthough calcineurin inhibitors (CNIs) have a well-established role in the prevention of graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (HCT), their use can be limited by significant toxicities, which may result in premature treatment discontinuation. The optimal management of patients with CNI intolerance is unknown. The objective of this study was to determine the effectiveness of corticosteroids as GVHD prophylaxis for patients with CNI intolerance. MethodsThis retrospective single-center study included consecutive adult patients with hematologic malignancies who underwent myeloablative peripheral blood allogeneic HCT with anti-thymocyte globulin, CNI, and methotrexate GVHD prophylaxis in Alberta, Canada. Multivariable competing-risks regression was used to compare cumulative incidences of GVHD, relapse, and non-relapse mortality between recipients of corticosteroid versus continuous CNI prophylaxis, and multivariable Cox proportional hazards regression was applied to compare overall survival, relapse-free survival (RFS) and moderate-to-severe chronic GVHD and RFS. ResultsAmong 509 allogeneic HCT recipients, 58 (11%) patients developed CNI intolerance and were switched to corticosteroid prophylaxis at median 28 days (range 1-53) after HCT. Compared with patients who received continuous CNI prophylaxis, recipients of corticosteroid prophylaxis had significantly greater cumulative incidences of grade 2-4 acute GVHD (subhazard ratio [SHR] 1.74, 95% confidence interval [CI] 1.08–2.80, P = 0.024), grade 3–4 acute GVHD (SHR 3.22, 95% CI 1.55–6.72, P = 0.002), and GVHD-related non-relapse mortality (SHR 3.07, 95% CI 1.54–6.12, P = 0.001). There were no significant differences in moderate-to-severe chronic GVHD (SHR 0.84, 95% CI 0.43–1.63, P = 0.60) or relapse (SHR 0.92, 95% CI 0.53–1.62, P = 0.78), but corticosteroid prophylaxis was associated with significantly inferior overall survival (hazard ratio [HR] 1.77, 95% CI 1.20–2.61, P = 0.004), RFS (HR 1.54, 95% CI 1.06–2.25, P = 0.024), and chronic GVHD and RFS (HR 1.46, 95% CI 1.04–2.05, P = 0.029). ConclusionsAllogeneic HCT recipients with CNI intolerance are at increased risks of acute GVHD and poor outcomes despite institution of corticosteroid prophylaxis following premature CNI discontinuation. Alternative GVHD prophylaxis strategies are needed for this high-risk population.

1591. The Impact of Pretransplant Respiratory Virus Infection in Pediatric Hematopoietic Cell Transplant Recipients

Abstract Background Respiratory virus infections (RVIs) in adult hematopoietic cell transplant (HCT) candidates have been shown to impact posttransplant outcomes; however, there are few studies in pediatric patients. We sought to evaluate the role of specific viruses and the location of viral infection on post HCT outcomes. Methods We evaluated allogeneic pediatric HCT recipients receiving myeloablative conditioning from 3/2010–3/2018. All patients had a multiplex PCR for RVIs prior to HCT, regardless of symptoms. Delaying HCT was recommended when feasible for RSV, parainfluenza, metapneumovirus, adenovirus, and influenza, but not routinely for human rhinovirus (HRV) and endemic coronaviruses. We utilized Cox proportional hazards models to evaluate progression to lower respiratory disease (LRD) post HCT and linear regression models to evaluated days alive and out of hospital (DAOH) by 100 days post HCT. Results Of 310 allogeneic HCT recipients receiving myeloablative conditioning, 133 (43%) were positive for a RVI before HCT. Baseline characteristics were notable for differences for age, recipient CMV serostatus, and delayed HCT (Table 1). The most common RVI was HRV (97, 73%) and 81 (61%) patients were symptomatic at the time of detection. Most patients had a URI (92%) and 11 patients had LRD (3 proven, 8 possible). In univariate analysis, HRV as virus type was associated with fewer DAOH and preHCT URI as location of viral infection (with and without symptoms) trended towards fewer DAOH (Figure 1a). When adjusted for age, preHCT lymphocyte count, cell source, and conditioning regimen, both HRV and preHCT URI showed a trend towards fewer DAOH, but no significant association was found (Figure 1b,c). Twenty patients progressed to LRD after HCT with the same preHCT RVI; no factors, including delay of transplant, were associated with reduced progression to LRD. (A) Univariable linear regression for DAOH, (B) Multivariable linear regression for DAOH by viral type, (C) Multivariable linear regression for DAOH by viral location and symptom composite. Conclusion In this single center study, HRV as virus type and URI as location of viral infection before myeloablative allogeneic HCT were associated with increased hospitalization after HCT, but not in multivariate models. Larger multicenter studies are needed to provide timely evaluation and adequate statistical power to definitively determine role of URI versus LRD and the impact of transplant delay and treatment strategies. Disclosures Yae-Jean Kim, MD, PhD, Janssen: Grant/Research Support|Korean Society of Pediatric Infectious Diseases: Grant/Research Support|Ministry of Trade, Industry and Energy: Grant/Research Support|MSD: Grant/Research Support chikara Ogimi, MD, Horiba: payment for a lecture Michael J. Boeckh, MD PhD, Allovir: Advisor/Consultant|Amazon: Grant/Research Support|Ansun Biopharma: Grant/Research Support|EvrysBio: Advisor/Consultant|Gates Ventures: Grant/Research Support|Gilead Sciences: Advisor/Consultant|Gilead Sciences: Grant/Research Support|GlaxoSmithKline: Advisor/Consultant|GlaxoSmithKline: Grant/Research Support|Helocyte: Advisor/Consultant|Janssen: Advisor/Consultant|Janssen: Grant/Research Support|Kyorin Pharmaceuticals: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Moderna: Advisor/Consultant|Moderna: Grant/Research Support|Regeneron: Grant/Research Support|ReViral: Advisor/Consultant|Symbio: Advisor/Consultant|Takeda: Grant/Research Support|Vir Biotechnology: Advisor/Consultant|Vir Biotechnology: Grant/Research Support Janet A. Englund, MD, Astra Zeneca: Advisor/Consultant|Astra Zeneca: Grant/Research Support|GlaxoSmithKline: Grant/Research Support|Meissa Vaccine: Advisor/Consultant|Merck: Grant/Research Support|Pfizer: Grant/Research Support|SanofiPasteur: Advisor/Consultant Alpana Waghmare, MD, Allovir: Grant/Research Support|Ansun Biopharma: Grant/Research Support|Devarra Therapeutics: DSMB|Kyorin Pharmaceutical: Advisor/Consultant|Pfizer: Grant/Research Support|Vir/GSK: Grant/Research Support.

Prognostic Biomarkers for Hepatic Veno-Occlusive Disease/Sinusoidal Obstruction Syndrome in Myeloablative Allogeneic Hematopoietic Cell Transplantation: Results from the Blood and Marrow Transplant Clinical Trials Network 1202 Study

Hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is a potentially life-threatening complication of hematopoietic cell transplantation (HCT). This study aimed to determine a blood biomarker signature early post-HCT that identifies patients at high risk for VOD/SOS. A set of 23 plasma biomarkers, selected from the VOD/SOS literature, was measured on days 0, 7, and 14 after myeloablative HCT using blood samples from patients enrolled in the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) Protocol 1202. Eligible cases were diagnosed with VOD/SOS in BMT CTN 1202 using the Baltimore criteria. Controls (without VOD/SOS) were matched to cases for conditioning regimen and age. Significant biomarkers were identified using the Bonferroni-adjusted Wilcoxon rank-sum test (P ≤ .002). Thirty-three patients with mild or severe VOD/SOS were identified (cases) and matched to 107 controls. Two, 8, and 5 biomarkers measured from the plasma of these patients were significantly associated with the development of VOD/SOS at days 0, 7, and 14, respectively, with the strongest associations on days 7 and 14. Biomarker associations were stronger for severe VOD/SOS risk and were stronger prognostic markers for VOD/SOS cases occurring within 28 days of HCT. Hyaluronan was most strongly associated with VOD/SOS risk, with an area under the receiver operating characteristic curve (AUC) of .81 on day 7 and .79 on day 14. Multivariate models of up to 5 biomarkers generated AUCs ranging from .82 to .85. All associations with VOD/SOS risk were independent of clinical risk factors. This study confirms previously identified biomarkers of VOD/SOS risk and identified novel prognostic biomarker signatures that identify patients at risk for VOD/SOS shortly after HCT. Multivariate analysis suggests that a combination of up to 5 of these protein biomarkers may provide a prognostic tool for identifying patients at risk for VOD/SOS.

Long-Term Outcome of Low Dose of Anti-t-Lymphocyte Globulin in the Prophylaxis of Graft-Versus-Host Disease in Unrelated Myeloablative Hematopoietic Stem Cell Transplantation

INTRODUCTION In vivo T-cell depletion with Anti-T-lymphocyte globulin (ATLG; Grafalon) is one of the strategies used in the graft-versus-host disease (GVHD) prevention in the setting of hematopoietic stem cell transplantation (HSCT). One open-label randomized trial in HLA-matched unrelated myeloablative HSCT have reported the reduction of cGVHD with the incorporation of ATLG (60mg/Kg), however progression-free survival (PFS) and overall survival (OS) were lower than in the placebo group1. Other randomized trial in related myeloablative HSCT, using an inferior dose of ATLG (30mg/Kg), have reported this reduction in GVHD results without increasing transplantation-related mortality (TRM) or disease relapse (DR)2. Based on this, the policy in our center is to use a lower dose of ATLG (21mg/Kg) in unrelated myeloablative HSCT. The aim of this study is to analyze the outcome of this strategy in terms of GVHD results, PFS, OS, TRM and DR. METHODS We conducted a retrospective study in all patients who underwent a HLA-matched unrelated myeloablative HSCT at our institution between 2013 and 2021. Patients received a total dose of 21mg/Kg of ATLG divided into three doses of 7mg/Kg on days -3, -2 and -1. The primary endpoints were cumulative incidence (CI) of aGVHD, CI of moderate-severe cGVHD, PFS and OS. Secondary endpoints were TRM, CI of DR and toxicity. RESULTS Sixty-one patients were included. The median age was 51 years. Thirty-seven (60,7%) were men. Twenty-three (37,7%) patients had an acute myeloid leukemia (AML). Eighteen (29,5%) patients had an HLA-mismatched donor. Forty-two (68,8%) receive a Bu-Flu conditioning. Cyclosporine combined with mycophenolate mofetil (MMF) or short course of methotrexate (MTX) as GCVH prophylaxis was used in 43 patients (70,5%). Clinical characteristics of patients are showed in table 1. The median follow-up of the alive patients was 36 months. A median value of 0.1 x 106/L lymphocytes was observed on the first day of infusion. In 35 patients (57,4%) a grade 1 to 2 infusion reaction was reported and in 3 (4,9%) a grade 3 to 4. Those three patients did not complete all infusions, the rest of patients did. Median time to neutrophil engraftment (3 consecutive days of >500/μL) was 15 days (IR, 13-18) and to platelet engraftment (3 consecutive days of self-supported platelets >20000/μL) was 17 days (IR, 15-23). CI of aGVHD grade 2 to 4 within 180 days after HSCT was 39,5% (95% CI, 27,1% to 51,6%) and CI of aGVHD grade 3 to 4 was 11,6% (95% CI, 5,0% to 21%), CI of moderate-severe cGVHD at two years was 20,9% (95% CI, 11,4% to 32,4%). PFS at two years was 59,6% (95% CI, 47% to 71%) and OS at two years was 71,8% (95% CI, 59% to 83%). The cGVHD relapse free survival (cGRFS) at two years was 36,2% (95 CI, 24% to 48%). The CI of RD at two years was 23,3% (95% CI, 13% to 35,3%) and the TRM at two years was 17,1% (95% CI, 8,7% to 27,9%). Median time to cyclosporine or tacrolimus withdrawal was 6,7 months (interquartile range, 5-8 months) and median of use of any type of immunosuppressors (i.e corticosteroids) from the day of HSCT was 6,9 months (interquartile range, 5-10 months). In 4 (6,6%) patients a primary graft failure was reported, and two patients developed post-transplantation lymphoproliferative disease. CONCLUSSIONS The use of ATLG at dose of 21 mg/Kg in HLA-matched unrelated myeloablative HSCT offers promising results of OS and PFS with a low TRM, despite being related to a higher incidence of aGVHD and cGVHD than previously trials were the ATLG dose was higher. It showed a better profile of tolerability and adverse effects. More investigation should be undertaken to determine the appropriate dose of ATLG in this type of HSCT. REFERENCES 1. Soiffer RJ, Kim HT, McGuirk J, Horwitz ME et al. Randomized, Double-Blind, Phase III Clinical Trial of Anti-T-Lymphocyte Globulin to Assess Impact on Chronic Graft-Versus-Host Disease-Free Survival in Patients Undergoing HLA-Matched Unrelated Myeloablative Hematopoietic Cell Transplantation. J Clin Oncol. 2017 Dec 20;35(36):4003-4011. doi: 10.1200/JCO.2017.75.8177. Epub 2017 Oct 17. PMID: 29040031; PMCID: PMC8462523. 2. Kröger N, Solano C, Wolschke Cet al. Antilymphocyte Globulin for Prevention of Chronic Graft-versus-Host Disease. N Engl J Med. 2016 Jan 7;374(1):43-53. doi: 10.1056/NEJMoa1506002. PMID: 26735993. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Phase II Study of Myeloablative 8/8- or 7/8-Matched Allotransplantation with Post-Transplant Cyclophosphamide, Tacrolimus, and Mycophenolate Mofetil: Marked Reduction in Gvhd Risk without Increased Relapse Risk Compared to Historical Cyclosporine/Methotrexate

Introduction Allogeneic hematopoietic cell transplantation (HCT) is the only potentially curative treatment for many high-risk hematologic malignancies. Myeloablative conditioning (MAC) is currently the standard of care for young and fit patients; however, graft-versus host disease (GVHD) continues to be a major limitation to the success of HCT, increasing post-transplant morbidity and mortality. An ideal HCT is one that combines strategies to reduce the incidence and severity of GVHD, without compromising graft versus-tumor effect. We hypothesized that the GVHD prophylaxis regimen consisting of post-transplant cyclophosphamide (PTCy), tacrolimus (Tac) and mycophenolate mofetil (MMF) would reduce the incidence of chronic GVHD in patients receiving a standard MAC HCT without an increase in risk of malignant relapse. Methods This is an analysis of a phase II study at the University of Minnesota using a MAC regimen of either: 1. total body irradiation (TBI, total dose 1320 cGy administered twice a day from days -4 to -1) or 2. Busulfan 3.2mg/kg daily (cumulative AUC 19,000 - 21,000 μmol/min/L) plus fludarabine 160mg/m2 days -5 to -2 for patients unable to receive further radiation, followed by a GVHD prophylaxis regimen of PTCy (50mg/kg days +3 and +4), Tac and MMF (beginning day +5). The primary endpoint is cumulative incidence of chronic GVHD requiring systemic immunosuppressive treatment at 1 year post-transplant. Eligibility included: age ≤ 60 years, malignant or non-malignant diagnosis, matched related (MRD) or unrelated (MUD) donor with either a bone marrow (BM) or filgrastim-mobilized peripheral blood (PB) graft. We compared those results to our previous MAC protocol which utilized a regimen of either cyclophosphamide (60mg/kg days -6 and -5)/TBI (1320 cGy administered twice a day from days -4 to -1) or busulfan (0.8 mg/kg/dose IV in 4 daily doses days -9 to -6 [total 12.8 mg/kg])/ cyclophosphamide (50 mg/kg days -5 to -2) and GVHD prophylaxis consisted of cyclosporine and methotrexate. Results Through June 2022, we treated 125 patients with a median follow up of 472 days post-transplant. Of those, 48% were female and 22 (17.6%) were ≤ 18 years old with median age at HCT of 38 years (range, 1-59 yrs; Interquartile range [IQR], 22-50 yrs). Donor source was 8/8 MRD in 69 patients (55.2%), 8/8 MUD in 44 (35.2%), and 7/8 MUD in 12 (9.6%). Graft source was bone marrow in 43 patients (34.4%) and PB in 82 (65.6%). Preparative regimen was TBI in 89.6% of patients. 124 of 125 patients achieved primary neutrophil engraftment by 42 days, median 16 days (range, 13-30). 119 of 125 achieved platelet engraftment by 6 months, median 25.5 days (range, 14-98). 91 patients (72.8%) required total parenteral nutrition (TPN) for oral mucositis and regimen-related toxicities during their initial transplant admission. Cumulative incidence of Grade II-IV acute GVHD by day +100 was 16% (95% confidence interval (CI): 9-23%); Grade III-IV acute GVHD was 4% (CI: 0-8%). No patients experienced grade IV GVHD and there were no deaths due to GVHD. At 1 year, only 3 of 105 patients developed chronic GVHD requiring immune suppression, for a cumulative incidence of 4% (CI: 0-8%). Two-year cumulative incidence of relapse was 25% (CI: 15-36%). Two-year overall survival was 80% (CI: 69-87%) and two-year GVHD-free relapse free survival (GRFS) was 57% (CI: 45-67%). Kaplan-Meier curves comparing overall survival and GRFS between this cohort and our previous MAC protocol without PTCy are shown in Figure 1. Figure 2 shows the comparison between these two consecutive cohorts in incidence of acute and chronic GVHD, transplant-related mortality (TRM) and relapse. Discussion Myeloablative HCT with a TBI or Busulfan/Fludarabine-based preparative regimen, followed by a GVHD prophylaxis regimen of PTCy, Tac, and MMF results in extremely low incidence of chronic GVHD, the primary objective of this clinical trial. Importantly, this regimen is feasible and effective for pediatric and adult patients. Further improvement in outcomes could potentially be achieved by incorporating post-transplant relapse mitigating strategies as well as supportive care measures to decrease regimen-related toxicities. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Ultra-Sensitive Next-Generation Sequencing Establishes the Prognostic Value of Very Low MRD in Adults with Acute Lymphoblastic Leukemia Undergoing Hematopoietic Cell Transplantation

BACKGROUND The prognostic utility of measurable residual disease (MRD) in adult acute lymphoblastic leukemia (ALL) has been defined at a sensitivity of 10-4. Measurement of MRD by ultra-sensitive next-generation sequencing (NGS) of Ig and/or TCR rearrangements has a sensitivity of 10-6 and is increasingly used across the United States to evaluate treatment response. However, the clinical utility of very low level NGS-based MRD (<10-4) is unknown. In this large multicenter cohort of adult ALL patients who underwent allogeneic hematopoietic cell transplant (HCT), we evaluated the prognostic value of ultra-sensitive NGS-based MRD. METHODS Adults (18+) with ALL who underwent HCT at Stanford University or Oregon Health and Science University (OHSU) between January 2014 and April 2021 with planned MRD monitoring using the NGS-based clonoSEQ assay (Adaptive Biotechnologies, Seattle, WA) were included. Pre-HCT MRD (MRDpre) and post-HCT MRD (MRDpost) were followed for up to one-year post-HCT. MRD was evaluated as residual clonal cells per million nucleated cells and was defined as undetectable (0), low (<10-4), high (≥10-4 to ≤10-3) and very high (>10-3). Patients were followed for leukemia relapse for up to two years. Competing-risks analyses were used to model the hazard of relapse according to MRDpre and MRDpost levels. A univariate analysis using a Fine-Gray subdistribution hazard competing risk regression model was used to estimate the effect of MRDpre level on the cumulative incidence of relapse. A Cox regression model with time-varying covariates was fit to evaluate the association between MRDpre and MRDpost levels with relapse. RESULTS 158 ALL patients who underwent HCT (Stanford n = 116, OHSU n = 42) had a trackable clonoSEQ clone. The median age was 43 years (range 18-77); 136 patients (86%) had B-ALL, 22 (14%) had T-ALL, and 131 (83%) underwent myeloablative HCT. Of the 122 patients with MRDpre assessment, MRDpre was undetectable, low, high, and very high in 82 (67%), 24 (20%), 11 (9%), and 5 (4%), respectively. Of the 111 patients with both MRDpre and at least one MRDpost assessments, 38 had at least one positive MRDpost result. The cumulative incidence of relapse differed significantly according to level of MRDpre (Figure 1), including among patients with low MRDpre of <10-4 where post-HCT relapse risk was strikingly higher than in patients with undetectable MRDpre (HR 3.56, 95% CI 1.39-9.15, p = 0.01). A very strong association with post-HCT relapse was also seen in patients with detectable MRDpost at any level (including <10-4), even after controlling for MRDpre (HR 4.41, 95% CI 2.90-6.70, p < 0.0001). Finally, we found that patients entering HCT with undetectable MRDpre who remained undetectable through the first year of MRDpost monitoring had <10% likelihood of relapse in the second post-HCT year (Figure 2). In contrast, patients entering HCT with detectable MRDpre had an ongoing risk of continued detectable of MRDpost without a clear plateau of relapse risk post-HCT. CONCLUSION In this analysis across two large transplant centers, we found that detection of MRD by ultra-sensitive NGS at a level of 10-6 offers significant prognostic value in adults with ALL undergoing HCT. Detectable MRDpre even at a low level of <10-4 increases the risk of post-HCT relapse. The presence of MRDpost at any level following HCT also substantially increases the risk of relapse. Finally, we found that patients with undetectable MRDpre who continue to have undetectable MRDpost through the first year of monitoring have excellent post-HCT outcomes. *ECL, SD, and JS contributed to this work equally Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Health-Related Quality of Life Following Allogeneic Hematopoietic Cell Transplantation with Omidubicel versus Umbilical Cord Blood

Omidubicel is an advanced cell therapy derived from umbilical cord blood (UCB) for use in allogeneic hematopoietic cell transplantation (HCT). A recent randomized phase 3 clinical trial demonstrated faster engraftment, shorter length of hospital stays, and lower rates of infection with omidubicel compared with standard UCB transplantation in patients with high-risk hematologic malignancies. Despite the proven clinical benefits of omidubicel, its impact on health-related quality of life (HRQL) from the patient's perspective has not been described. This study analyzed patient-reported HRQL measures collected prospectively in the randomized phase 3 trial comparing omidubicel to standard UCB transplantation. A total of 108 patients at 33 international stem cell transplantation centers underwent myeloablative allogeneic HCT with either omidubicel or standard UCB. Patients completed serial HRQL questionnaires at screening and on days 42, 100, 180, and 365 post-transplantation. The HRQL surveys included the Functional Assessment of Cancer Therapy-Bone Marrow Transplant (FACT-BMT), a 50-item cancer-specific questionnaire assessing physical, functional, emotional, social/family, and HCT-specific well-being, and the EuroQol 5-Dimension 3-Level, a 5-item generic HRQL survey. A mixed model with repeated measures was used to compare changes in HRQL from baseline in the 2 treatment arms. The average change in HRQL scores over time was compared by estimating the difference in the area under the curve (AUC) in each treatment group. Seventy-five patients (omidubicel arm, n=37; standard UCB arm, n=38) who completed the FACT-BMT at baseline and on 1 or more follow-up visits were included in this study. Baseline characteristics were similar in the 2 treatment arms. Over the first year post-transplantation, the AUCs of mean changes in physical, functional, and total FACT-BMT scores indicated significantly better HRQL with omidubicel (P < .05), with mean differences across time points ranging from 1.4 to 3.1 points, 1.6 to 3.2 points, and 7.2 to 11.0 points, respectively. The minimal clinically important difference was exceeded at 1 or more time points for each of these measures. The HRQL improvements with omidubicel were observed as early as 42 days post-transplantation and persisted at 1 year, indicating the potential long-term benefits of omidubicel on HRQL. Across all patients, adverse clinical outcomes, such as grade 3 viral infections and lower rates of neutrophil engraftment, were associated with worse HRQL scores. The observed improvements in HRQL measures may reflect the known clinical benefits of omidubicel. Compared with standard UCB, allogeneic HCT with omidubicel resulted in significant and clinically meaningful improvements in patient-reported HRQL measures.

Incomplete chimerism following myeloablative and anti-thymocyte globulin-conditioned hematopoietic cell transplantation is a risk factor for relapse and chronic graft-versus-host disease

Background aimsThe value of routine chimerism determination after myeloablative hematopoietic cell transplantation (HCT) is unclear, particularly in the setting of anti-thymocyte globulin (ATG)-based graft-versus-host disease (GVHD) prophylaxis. MethodsBlood samples were collected at 3 months post-HCT from 558 patients who received myeloablative conditioning and ATG-based GVHD prophylaxis. Chimerism was assessed using multiplex polymerase chain reaction of short tandem repeats in sorted T cells (CD3+) and leukemia lineage cells (CD13+CD33+ for myeloid malignancies and CD19+ for B-lymphoid malignancies). ATG exposure was determined using a flow cytometry-based assay. The primary outcomes of interest were relapse and chronic GVHD (cGVHD). ResultsIncomplete (<95%) T-cell chimerism and leukemia lineage chimerism were present in 17% and 4% of patients, respectively. Patients with incomplete T-cell chimerism had a significantly greater incidence of relapse (36% versus 22%, subhazard ratio [SHR] = 2.03, P = 0.001) and lower incidence of cGVHD (8% versus 25%, SHR = 0.29, P < 0.001) compared with patients with complete chimerism. In multivariate modeling, patients with high post-transplant ATG area under the curve and any cytomegalovirus (CMV) serostatus other than donor/recipient seropositivity (non-D+R+) had an increased likelihood of incomplete T-cell chimerism. Patients with incomplete leukemia lineage chimerism had a significantly greater incidence of relapse (50% versus 23%, SHR = 2.70, P = 0.011) and, surprisingly, a greater incidence of cGVHD (45% versus 20%, SHR = 2.64, P = 0.003). ConclusionsHigh post-transplant ATG exposure and non-D+R+ CMV serostatus predispose patients to incomplete T-cell chimerism, which is associated with an increased risk of relapse. The increased risk of cGVHD with incomplete B-cell/myeloid chimerism is a novel finding that suggests an important role for recipient antigen-presenting cells in cGVHD pathogenesis.

Respiratory viruses in hematopoietic cell transplant candidates: impact of preexisting lower tract disease on outcomes

AbstractPretransplant respiratory virus infections (RVIs) have been shown to negatively affect hematopoietic cell transplantation (HCT) outcomes. The impact of and need for delay of HCT for pretransplant infection with human rhinovirus (HRV) or endemic human coronavirus (HCoV; 229E, OC43, NL63, and HKU1) remain controversial. We analyzed the impact of symptomatic RVI within ≤90 days before HCT on overall mortality, posttransplant lower respiratory tract disease (LRD), and days alive and out of hospital (DAOH) by day 100 post-HCT in multivariable models. Among 1,643 adult HCT recipients (58% allogeneic recipients), 704 (43%) were tested for RVI before HCT, and 307 (44%) tested positive. HRV was most commonly detected (56%). Forty-five (15%) of 307 HCT recipients had LRD with the same virus early after HCT. Pretransplant upper respiratory tract infection (URI) with influenza, respiratory syncytial virus, adenovirus, human metapneumovirus, parainfluenza virus, HRV, or endemic HCoV was not associated with increased overall mortality or fewer DAOH. However, in allogeneic recipients who received myeloablative conditioning, LRD due to any respiratory virus, including HRV alone, was associated with increased overall mortality (adjusted hazard ratio, 10.8 [95% confidence interval, 3.29-35.1] for HRV and 3.21 [95% confidence interval, 1.15-9.01] for all other viruses). HRV LRD was also associated with fewer DAOH. Thus, the presence of LRD due to common respiratory viruses, including HRV, before myeloablative allogeneic HCT was associated with increased mortality and hospitalization. Pretransplant URI due to HRV and endemic HCoV was not associated with these outcomes. Improved management strategies for pretransplant LRD are warranted.

Impact of FLT3 internal tandem duplication and NPM1 mutations in acute myeloid leukemia treated with allogeneic hematopoietic cell transplantation

Background aimsThe internal tandem duplication of FLT3 (FLT3ITD) and NPM1 mutations (NPM1mut) are well-established prognostic factors in cytogenetically intermediate-risk acute myeloid leukemia (AML) when treated with chemotherapy alone. However, their prognostic value in the setting of allogeneic hematopoietic cell transplantation (HCT) is controversial. MethodsFLT3 and NPM1 mutational status was determined at diagnosis using single-gene polymerase chain reaction or next-generation sequencing in 247 adult patients with cytogenetically intermediate-risk AML who underwent myeloablative HCT. Multivariate Fine–Gray and Cox regression was used to analyze the cumulative incidence of relapse (CIR), relapse-free survival (RFS) and overall survival (OS). ResultsFLT3ITD and NPM1mut were present in 74 of 247 (30%) and 79 of 247 (32%) patients, respectively. There was no significant difference between patients without a FLT3ITD or NPM1mut (FLT3NONITD/NPM1WT) and patients with a FLT3ITD mutation alone (FLT3ITD/NPM1WT) with regard to CIR (P = 0.60), RFS (P = 0.91) or OS (P = 0.66). Similarly, there was no significant difference between FLT3NONITD/NPM1WT and FLT3NONITD/NPM1mut patients with regard to CIR (P = 0.70), RFS (P = 0.75) or OS (P = 0.95). The presence of a concurrent mutation in NPM1 did not appear to modify the impact of having a FLT3ITD mutation. ConclusionsIn contrast to chemotherapy-only treatment, FLT3 and NPM1 mutational status does not appear to predict outcomes in patients with cytogenetically intermediate-risk AML following HCT. These results suggest that HCT may ameliorate the poor prognostic effect of FLT3ITD mutation and that HCT should be considered over chemotherapy-only treatment in FLT3ITD-mutated AML.

Chimerism of Blood T-Cells and Leukemia Lineage Cells Following Myeloablative Hematopoietic Cell Transplantation Is a Risk Factor for Relapse and Chronic Graft-Versus-Host Disease

Background: Mixed chimerism of blood leukemia lineage cells has been reported to be highly predictive of relapse (Mattsson J et al. Leukemia 2001), but the utility of T-cell chimerism is controversial.Methods: Chimerism of T-cells (CD3 +) and leukemic lineage cells (CD13 +/CD33 + for myeloid malignancies and CD19 + for B-lymphoid malignancies) was measured in the peripheral blood for 600 hematopoietic cell transplant (HCT) recipients at 3-months post-transplant. Conditioning was myeloablative (fludarabine+busulfan+4GyTBI) and GVHD prophylaxis was with ATG+CsA+MTX.Results: Mixed (<95% donor) chimerism was present in 6% of patients in the leukemic lineage and 16% of patients in T-cells. Compared to patients with complete chimerism (≥95%), mixed chimerism predicted a significantly greater incidence of relapse (52% vs. 27%, P=0.044), and surprisingly, also a greater incidence of cGVHD (43% vs. 23%, P=0.028). Patients with mixed leukemic lineage chimerism also had poorer cGRFS (7% vs. 39%, P<0.001) and OS (29% vs. 55%, P<0.001). Mixed T-cell chimerism predicted a significantly greater incidence of relapse (46% vs. 24%, P<0.001) and lower cGVHD incidence (9% vs. 31%), with no difference in cGRFS or OS. The sensitivity/specificity/positive predictive value (PPV)/negative predictive value (NPV) of mixed leukemic lineage and T-cell chimerism for relapse were 65%/55%/35%/81% and 66%/57%/60%/79%, respectively. Sensitivity/specificity/PPV/NPV was similarly poor for cGVHD. In patients with complete leukemic lineage chimerism at 3-months, a ≥5% drop in donor chimerism at any future timepoint had sensitivity/specificity/PPV/NPV of 82%/79%/79%/82% for subsequent relapse.Conclusion: In the setting of myeloablative conditioning and ATG-based GVHD prophylaxis, mixed chimerism at 3-months post-transplant is a risk factor for subsequent relapse. However, the utility of these measurements in guiding medical interventions may be limited by insufficient predictive values. Nevertheless, patients with mixed chimerism may be candidates for more intensive surveillance. DisclosuresStorek: Atara Biotherapeutics: Other: Site PI, Research Funding.

Clinical Experience in the Randomized Phase 3 Sierra Trial: Anti-CD45 Iodine (131I) Apamistamab [Iomab-B] Conditioning Enables Hematopoietic Cell Transplantation with Successful Engraftment and Acceptable Safety in Patients with Active, Relapsed/Refractory AML Not Responding to Targeted Therapies

Clinical Experience in the Randomized Phase 3 Sierra Trial: Anti-CD45 Iodine (131I) Apamistamab [Iomab-B] Conditioning Enables Hematopoietic Cell Transplantation with Successful Engraftment and Acceptable Safety in Patients with Active, Relapsed/Refractory AML Not Responding to Targeted Therapies

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

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

Low Incidence of Chronic Graft-Versus-Host Disease in Myeloablative Allogeneic Hematopoietic Cell Transplantation with Post-Transplant Cyclophosphamide Using Matched Related or Unrelated Donors: Phase II Study Interim Analysis

Low Incidence of Chronic Graft-Versus-Host Disease in Myeloablative Allogeneic Hematopoietic Cell Transplantation with Post-Transplant Cyclophosphamide Using Matched Related or Unrelated Donors: Phase II Study Interim Analysis