The Adverse Event Landscape of Stem Cell Transplant: Evidence for aGVHD Driving Early Transplant Associated Toxicities

Although unrelated-donor (URD) hematopoietic cell transplantation (HCT) is associated with many toxicities, a detailed analysis of adverse events, as defined by the Common Terminology Criteria for Adverse Events (CTCAE), has not previously been curated. This represents a major unmet need, especially as it relates to assessing the safety of novel agents. We analyzed a detailed AE database from the "ABA2" randomized, double-blind, placebo-controlled clinical trial of abatacept for acute graft-versus-host disease (aGVHD) prevention, for which the FDA mandated a detailed AE assessment through Day +180, and weekly neutrophil and platelet counts through Day +100. These were analyzed for their relationship to key transplant outcomes, with a major focus on the impact of aGVHD on the development/severity of AEs. A total of 2102 AEs and 1816 neutrophil/platelet counts were analyzed from 142 8/8-HLA-matched URD HCT recipients on ABA2 (placebo cohort, n = 69, abatacept cohort, n = 73). This analysis resulted in 2 major observations. (1) Among graft source, conditioning intensity, age, and Grade 2 to 4 aGVHD, only aGVHD impacted Grade 3 to 5 AE acquisition after the first month post-transplant. (2) The development of Grade 3 to 4 aGVHD was associated with thrombocytopenia. We have created a detailed resource for the transplant community by which to contextualize clinical toxicities after transplant. It has identified aGVHD as a major driver of post-HCT Grade 3 to 5 AEs, and underscored a link between aGVHD and thrombocytopenia. This establishes a critical safety framework upon which the impact of novel post-transplant aGVHD therapeutics should be evaluated. This trial was registered at www.clinicaltrials.gov (#NCT01743131).

Overlap chronic GVHD is associated with adverse survival outcomes compared to classic chronic GVHD

Chronic graft-versus-host-disease (cGVHD) is divided into two subtypes: classic (absence of acute GVHD features) and overlap cGVHD ('ocGVHD'), in which both chronic and acute GVHD clinical features are present simultaneously. While worse outcomes with ocGVHD have been reported, there are few recent analyses. We performed a secondary analysis of data from the ABA2 trial (N = 185), in which detailed GVHD data were collected prospectively and systematically adjudicated. Analyses included cumulative incidence of classic versus ocGVHD, their specific organ manifestations, global disease severity scores, non-relapse mortality (NRM), disease-free survival (DFS) and overall survival (OS) in these two cGVHD subtypes. Of 92 patients who developed cGVHD, 35 were classified as ocGVHD. The 1-year cumulative incidence, organ involvement, and global severity of classic and ocGVHD were similar between ABA2 patients receiving CNI/MTX+placebo and CNI/MTX+abatacept; thus, cohorts were combined for ocGVHD evaluation. This analysis identified ocGVHD as having significantly higher severity at presentation and at maximum global severity compared to classic cGVHD. OS and DFS were significantly lower for ocGVHD versus classic cGVHD. OcGVHD is associated with increased cGVHD severity scores, and is associated with decreased OS and DFS compared to classic cGVHD, underscoring the high risks with this cGVHD subtype.

Higher abatacept exposure after transplant decreases acute GVHD risk without increasing adverse events

In the ABA2 study, the T-cell costimulation blockade agent, abatacept, was safe and effective in preventing acute graft-versus-host disease (aGVHD) after unrelated-donor hematopoietic cell transplant (HCT), leading to US Food and Drug Administration approval. Here, we performed a determination of abatacept pharmacokinetics (PK), which enabled an examination of how abatacept exposure-response relationships affected clinical outcomes. We performed a population PK analysis of IV abatacept using nonlinear mixed-effect modeling and assessed the association between abatacept exposure and key transplant outcomes. We tested the association between the trough after dose 1 (Ctrough_1) and grade (GR) 2 or 4 aGVHD (GR2-4 aGVHD) through day +100. An optimal Ctrough_1 threshold was identified via recursive partitioning and classification tree analysis. This demonstrated that abatacept PK was characterized by a 2-compartment model with first-order elimination. The ABA2 dosing regimen was based on previous work targeting a steady-state abatacept trough of 10 μg/mL. However, a higher Ctrough_1 (≥39 μg/mL, attained in ∼60% of patients on ABA2) was associated with a favorable GR2-4 aGVHD risk (hazard ratio, 0.35; 95% confidence interval, 0.19-0.65; P < .001), with a Ctrough_1 <39 μg/mL associated with GR2-4 aGVHD risk indistinguishable from placebo (P = .37). Importantly, no significant association was found between Ctrough_1 and key safety indicators, including relapse, and cytomegalovirus or Epstein-Barr virus viremia. These data demonstrate that a higher abatacept Ctrough_1 (≥39 μg/mL) was associated with a favorable GR2-4 aGVHD risk, without any observed exposure-toxicity relationships. This trial was registered at www.clinicaltrials.gov as #NCT01743131.

Long-Term Organ Function After HCT for SCD: A Report From the Sickle Cell Transplant Advocacy and Research Alliance

Hematopoietic cell transplantation (HCT) is an established cure for sickle cell disease (SCD) supported by long-term survival, but long-term organ function data are lacking. We sought to describe organ function and assess predictors for dysfunction in a retrospective cohort (n = 247) through the Sickle cell Transplant Advocacy and Research alliance. Patients with <1-year follow-up or graft rejection/second HCT were excluded. Organ function data were collected from last follow-up. Primary measures were organ function, comparing pre- and post-HCT. Bivariable and multivariable analyses were performed for predictors of dysfunction. Median age at HCT was 9.4 years; the majority had HbSS (88.2%) and severe clinical phenotype (65.4%). Most received matched related (76.9%) bone marrow (83.3%) with myeloablative conditioning (MAC; 57.1%). Acute and chronic graft-versus-host disease (GVHD) developed in 24.0% and 24.8%. Thirteen patients (5.3%) died ≥1 year after HCT, primarily from GVHD or infection. More post-HCT patients had low ejection or shortening fractions than pre-HCT (0.6% → 6.0%, P = .007 and 0% → 4.6%, P = .003). The proportion with lung disease remained stable. Eight patients (3.2%) had overt stroke; most had normal (28.3%) or stable (50.3%) brain magnetic resonance imaging. On multivariable analysis, cardiac dysfunction was associated with MAC (odds ratio [OR] = 2.71; 95% confidence interval [CI], 1.09-6.77; P = .033) and severe acute GVHD (OR = 2.41; 95% CI, 1.04-5.62; P = .041). Neurologic events were associated with central nervous system indication (OR = 2.88; 95% CI, 2.00-4.12; P < .001). Overall organ dysfunction was associated with age ≥16 years (OR = 2.26; 95% CI, 1.35-3.78; P = .002) and clinically severe disease (OR = 1.64; 95% CI, 1.02-2.63; P = .043). In conclusion, our results support consideration of HCT at younger age and use of less intense conditioning.

Spatiotemporal single-cell profiling reveals that invasive and tissue-resident memory donor CD8+ T cells drive gastrointestinal acute graft-versus-host disease

Organ infiltration by donor T cells is critical to the development of acute graft-versus-host disease (aGVHD) in recipients after allogeneic hematopoietic stem cell transplant (allo-HCT). However, deconvoluting the transcriptional programs of newly recruited donor T cells from those of tissue-resident T cells in aGVHD target organs remains a challenge. Here, we combined the serial intravascular staining technique with single-cell RNA sequencing to dissect the tightly connected processes by which donor T cells initially infiltrate tissues and then establish a pathogenic tissue residency program in a rhesus macaque allo-HCT model that develops aGVHD. Our results enabled creation of a spatiotemporal map of the transcriptional programs controlling donor CD8⁺ T cell infiltration into the primary aGVHD target organ, the gastrointestinal (GI) tract. We identified the large and small intestines as the only two sites demonstrating allo-specific, rather than lymphodepletion-driven, T cell infiltration. GI-infiltrating donor CD8⁺ T cells demonstrated a highly activated, cytotoxic phenotype while simultaneously developing a canonical tissue-resident memory T cell (T_RM) transcriptional signature driven by interleukin-15 (IL-15)/IL-21 signaling. We found expression of a cluster of genes directly associated with tissue invasiveness, including those encoding adhesion molecules (ITGB2), specific chemokines (CCL3 and CCL4L1) and chemokine receptors (CD74), as well as multiple cytoskeletal proteins. This tissue invasion transcriptional signature was validated by its ability to discriminate the CD8⁺ T cell transcriptome of patients with GI aGVHD from those of GVHD-free patients. These results provide insights into the mechanisms controlling tissue occupancy of target organs by pathogenic donor CD8⁺ T_RM cells during aGVHD in primate transplant recipients.

Phase II Trial of Costimulation Blockade With Abatacept for Prevention of Acute GVHD

PURPOSE

Severe (grade 3-4) acute graft-versus-host disease (AGVHD) is a major cause of death after unrelated-donor (URD) hematopoietic cell transplant (HCT), resulting in particularly high mortality after HLA-mismatched transplantation. There are no approved agents for AGVHD prevention, underscoring the critical unmet need for novel therapeutics. ABA2 was a phase II trial to rigorously assess safety, efficacy, and immunologic effects of adding T-cell costimulation blockade with abatacept to calcineurin inhibitor (CNI)/methotrexate (MTX)-based GVHD prophylaxis, to test whether abatacept could decrease AGVHD.

METHODS

ABA2 enrolled adults and children with hematologic malignancies under two strata: a randomized, double-blind, placebo-controlled stratum (8/8-HLA-matched URD), comparing CNI/MTX plus abatacept with CNI/MTX plus placebo, and a single-arm stratum (7/8-HLA-mismatched URD) comparing CNI/MTX plus abatacept versus CNI/MTX CIBMTR controls. The primary end point was day +100 grade 3-4 AGVHD, with day +180 severe-AGVHD-free-survival (SGFS) a key secondary end point. Sample sizes were calculated using a higher type-1 error (0.2) as recommended for phase II trials, and were based on predicting that abatacept would reduce grade 3-4 AGVHD from 20% to 10% (8/8s) and 30% to 10% (7/8s). ABA2 enrolled 142 recipients (8/8s, median follow-up = 716 days) and 43 recipients (7/8s, median follow-up = 708 days).

RESULTS

In 8/8s, grade 3-4 AGVHD was 6.8% (abatacept) versus 14.8% (placebo) (P = .13, hazard ratio = 0.45). SGFS was 93.2% (CNI/MTX plus abatacept) versus 82% (CNI/MTX plus placebo, P = .05). In the smaller 7/8 cohort, grade 3-4 AGVHD was 2.3% (CNI/MTX plus abatacept, intention-to-treat population), which compared favorably with a nonrandomized matched cohort of CNI/MTX (30.2%, P < .001), and the SGFS was better (97.7% v 58.7%, P < .001). Immunologic analysis revealed control of T-cell activation in abatacept-treated patients.

CONCLUSION

Adding abatacept to URD HCT was safe, reduced AGVHD, and improved SGFS. These results suggest that abatacept may substantially improve AGVHD-related transplant outcomes, with a particularly beneficial impact on HLA-mismatched HCT.

Mixed-phenotype acute leukemia: A cohort and consensus research strategy from the Children's Oncology Group Acute Leukemia of Ambiguous Lineage Task Force

BACKGROUND

Optimal chemotherapy for treating mixed-phenotype acute leukemia (MPAL) and the role of hematopoietic stem cell transplantation (HSCT) remain uncertain. Major limitations in interpreting available data are MPAL's rarity and the use of definitions other than the currently widely accepted criteria: the World Health Organization 2016 (WHO2016) classification.

METHODS

To assess the relative efficacy of chemotherapy types for treating pediatric MPAL, the Children's Oncology Group (COG) Acute Leukemia of Ambiguous Lineage Task Force assembled a retrospective cohort of centrally reviewed WHO2016 MPAL cases selected from banking studies for acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Patients were not treated in COG trials; treatment and outcome data were captured separately. The findings were then integrated with the available, mixed literature to develop a prospective trial in pediatric MPAL.

RESULTS

The central review confirmed that 54 of 70 cases fulfilled WHO2016 criteria for MPAL. ALL induction regimens achieved remission in 72% of the cases (28 of 39), whereas AML regimens achieved remission in 69% (9 of 13). The 5-year event-free survival (EFS) and overall survival (OS) rates for the entire cohort were 72% ± 8% and 77% ± 7%, respectively. EFS and OS were 75% ± 13% and 84% ± 11%, respectively, for those receiving ALL chemotherapy alone without HSCT (n = 21).

CONCLUSIONS

The results of the COG MPAL cohort and a literature review suggest that ALL chemotherapy without HSCT may be the preferred initial therapy. A prospective trial within the COG is proposed to investigate this approach; AML chemotherapy and/or HSCT will be reserved for those with treatment failure as assessed by minimal residual disease. Embedded biology studies will provide further insight into MPAL genomics.

CD36-positive B-lymphoblasts Predict Poor Outcome in Children With B-lymphoblastic Leukemia

Objective We observed that pediatric patients with B lymphoblastic leukemia which expressed CD36 at diagnosis seemed to have worse outcome than patients whose blasts did not. Here, we describe the patient, disease characteristics, pathological, molecular, and genetic features and outcomes of patients with CD36+ B-LL compared to patients with CD36- B-LL. Methods We retrospectively reviewed all flow cytometry reports from September 2008 to December 2015 to identify patients diagnosed at our institution with CD36 expression on B lymphoblasts. CD36- control patients were chosen from our leukemia database and matched 2:1 to CD36+ patients for National Cancer Institute (NCI) risk group at diagnosis. We reviewed diagnostic marrow slides for cytoplasmic granules and abstracted clinical data from patient charts. To identify underlying genetic abnormalities, clinical FISH testing and RNA sequencing was performed on 5 of our CD36+ patients, and RNA-seq data from the NIH Therapeutically Applicable Research to Generate Effective Treatments (TARGET) ALL Expansion Phase 2 data set were examined. Results Twenty-five of 366 (6.83%) patients diagnosed at our institution in the study period had CD36+ blasts. With a median follow-up of 5.32 years, 5-year event-free survival (EFS) and overall survival (OS) were significantly worse for CD36+ patients compared to CD36- patients who were NCI Standard Risk at diagnosis (EFS: 60% ± 15.49 vs 95% ± 4.87, P = .016; OS: 90% ± 9.5 vs 100%, P = .019). NCI Standard Risk patients whose blasts were both CD36+ and had granules had the worst survival compared to CD36- patients without granules (EFS 25% ± 21.65 vs 95% ± 4.87, P = .0004). From our CD36+ patients and the TARGET database, we found 2 ABL2 mutations, 1 PDGFRB mutation, and 2 NRAS mutations. Conclusions For NCI Standard Risk patients, CD36 expression on B-lymphoblasts identifies patients with B-LL who have especially poor outcome. This may be due to underlying genetic abnormalities that may be amenable to targeted therapy.

Improved Splenic Function After Hematopoietic Stem Cell Transplant for Sickle Cell Disease

BACKGROUND

Splenic dysfunction is a significant complication of sickle cell disease (SCD). Hematopoietic stem cell transplant (HSCT) is a proven cure for SCD; however, its long-term effect on splenic function is not well characterized.

PROCEDURE

We conducted a retrospective cohort study of pediatric patients who had HSCT for SCD at two transplant centers. (99m) Tc liver-spleen (LS) scans were blindly reviewed and classified as demonstrating absent, decreased, or normal splenic uptake.

RESULTS

Considering all engrafted nonsplenectomized Hb SS and Sβ(0) -thalassemia patients with LS scans available, at a median of 2.0 years post-HSCT (range 1.0-9.3 years) eight of 53 (15%) had normal, 40 of 53 (75%) decreased, and five of 53 (9%) absent splenic uptake. More patients had splenic uptake after HSCT: pre-HSCT 14/38 (37%) versus post-HSCT 34/38 (89%), P < 0.0001. Older age at HSCT was associated with worse splenic function post-HSCT (median age at HSCT for absent uptake 16.6 years vs. present uptake 8.0 years, P = 0.030). Extensive chronic GVHD was also more common in patients with absent splenic uptake compared to patients with present uptake (absent 40% vs. present 6%, P = 0.064).

CONCLUSIONS

HSCT significantly improves splenic function for most pediatric patients with SCD, but older patient age at time of HSCT and extensive chronic GVHD appear to be risk factors for poor post-HSCT splenic function.

Immunophenotypic parameters and RBC alloimmunization in children with sickle cell disease on chronic transfusion

Alloimmunization against red blood cell (RBC) antigens is a cause of morbidity and mortality in transfused patients with sickle cell disease (SCD). To investigate distinguishing characteristics of patients who develop RBC alloantibodies after transfusion (responders) versus those who do not (non-responders), a cross-sectional study of 90 children with SCD on chronic RBC transfusion therapy at a single institution was conducted in which 18 immune parameters (including T and B cell subsets) were tested via flow cytometry, and medical records were reviewed. RBC alloimmunization was present in 26/90 (29%) patients, with anti-E, K, and C among the most commonly detected alloantibodies despite prophylactic matching for these antigens at the study institution. In addition, RBC autoantibodies had been detected in 18/26 (69%) of alloimmunized versus 7/64 (11%) of non-alloimmunized patients (P < 0.0001). Alloimmunized patients were significantly older (median 13.0 years vs. 10.7 years, P = 0.010) and had more RBC unit exposures (median 148 U vs. 82 U, P = 0.020) than non-alloimmunized patients. Sex, age at initiation of chronic transfusion, splenectomy, stroke, and transfusion outside of the study institution were not significantly associated with RBC alloimmunization. Alloimmunized patients had a significantly increased percentage of CD4+ T memory cells compared to non-alloimmunized patients (57% vs. 49%, P = 0.0047), with no other significant differences in immune cell subsets or laboratory values detected between these groups. Additional research of RBC alloimmunization is needed to optimize transfusion therapy and to develop strategies to prevent alloimmunization.

Red blood cell transfusions are associated with HLA class I but not H-Y alloantibodies in children with sickle cell disease

Blood transfusions can induce alloantibodies to antigens on red blood cells (RBCs), white blood cells and platelets, with these alloantibodies affecting transfusion and transplantation. While transfusion-related alloimmunization against RBC antigens and human leucocyte antigens (HLA) have been studied, transfusion-related alloimmunization to minor histocompatibility antigens (mHA), such as H-Y antigens, has not been clinically characterized. We conducted a cross-sectional study of 114 children with sickle cell disease (SCD) and tested for antibodies to 5 H-Y antigens and to HLA class I and class II. Few patients had H-Y antibodies, with no significant differences in the prevalence of any H-Y antibody observed among transfused females (7%), transfused males (6%) and never transfused females (4%). In contrast, HLA class I, but not HLA class II, antibodies were more prevalent among transfused than never transfused patients (class I: 33% vs. 13%, P = 0·046; class II: 7% vs. 8%, P = 0·67). Among transfused patients, RBC alloantibody history but not amount of transfusion exposure was associated with a high (>25%) HLA class I panel reactive antibody (Odds ratio 6·8, 95% confidence interval 2·1-22·3). These results are consistent with immunological responder and non-responder phenotypes, wherein a subset of patients with SCD may be at higher risk for transfusion-related alloimmunization.

Immune parameter analysis of children with sickle cell disease on hydroxycarbamide or chronic transfusion therapy

Sickle cell disease (SCD) is increasingly appreciated as an inflammatory condition associated with alterations in immune phenotype and function. In this cross-sectional study we performed a multiparameter analysis of 18 immune markers in 114 paediatric SCD patients divided by treatment group [those receiving hydroxycrabamide (HC, previously termed hydroxyurea), chronic transfusion (CT), or no disease-modifying therapy] and 29 age-matched African American healthy controls. We found global elevation of most immune cell counts in SCD patients receiving no disease-modifying therapy at steady state. Despite the decrease in percentage of haemoglobin S associated with CT therapy, the abnormal cellular immune phenotype persisted in patients on CT. In contrast, in both univariate and multivariate analysis, treatment with HC was associated with normalization of the vast majority of leucocyte populations. This study provides additional support for HC treatment in SCD, as it appears that HC decreases the abnormally elevated immune cell counts in patients with SCD.

Outcome of transplantation for acute lymphoblastic leukemia in children with Down syndrome

We report on 27 patients with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) who received allogeneic hematopoietic cell transplantation (HCT) between 2000 and 2009. Seventy-eight percent of patients received myeloablative conditioning and 52% underwent transplantation in second remission. Disease-free survival (DFS) was 24% at a median of 3 years. Post-transplant leukemic relapse was more frequent than expected for children with DS-ALL (54%) than for non-DS ALL. These data suggest leukemic relapse rather than transplant toxicity is the most important cause of treatment failure. Advancements in leukemia control are especially needed for improvement in HCT outcomes for DS-ALL.

Relative defects in mucosal immunity predict acute graft-versus-host disease

Impairment of gut mucosal immunity by the transplant process could facilitate translocation of commensal bacteria and thereby augment the graft-versus-host response. To begin to assess the influence of gut mucosal immunity on the development of acute graft-versus-host disease (GVHD), we conducted a prospective study in 24 pediatric allogeneic hematopoietic cell transplant recipients, assessing 4 fecal markers of mucosal immunity: calprotectin, soluble CD8 (sCD8), soluble intracellular adhesion molecule 1, and β-defensin-2. Stool samples were collected prospectively on transplant days 0, +5, +10, and +15 and analyzed by ELISA. Lower levels on day +5 (calprotectin and β-defensin-2) and day +10 (calprotectin, β-defensin-2, and sCD8) were associated with subsequent acute GVHD. The most striking difference was with calprotectin on day +10. Patients with levels below 424 mg/kg had an incidence of 77.8%, whereas those with levels above this threshold had a cumulative incidence of 0% (P = .002). Relative defects in gut mucosal immunity may be important in the pathogenesis of acute GVHD.

Comparable survival for pediatric acute myeloid leukemia with poor-risk cytogenetics following chemotherapy, matched related donor, or unrelated donor transplantation

BACKGROUND

We sought to better define the role of hematopoietic cell transplantation (HCT) in first remission (CR1) for high-risk pediatric acute myeloid leukemia (AML).

PROCEDURES

Outcomes were compared among patients aged less than 21 years with cytogenetically defined poor-risk AML treated with chemotherapy, matched related (MRD), or unrelated donor (URD) transplantation in CR1. Poor-risk cytogenetics was defined as monosomy 7/del7q, monosomy 5/del 5q, abnormalities of 3q, t(6;9)(p23;q34), or complex karyotype. Included are patients treated on Children's Oncology Group trials or reported to the Center for International Blood and Marrow Transplant Research from 1989 to 2006.

RESULTS

Of the 233 patients, 123 received chemotherapy, 55 received MRD HCT, and 55 received URD HCT. The 5-year overall survival from the time of consolidation chemotherapy or transplant conditioning was similar: chemotherapy (43% ± 9%), MRD (46% ± 14%), or URD (50% ± 14%), P = 0.99. Similarly, multivariate analysis demonstrated no significant differences in survival [(reference group = chemotherapy); MRD HR 1.08, P = 0.76; URD HR 1.13, P = 0.67] despite lower relapse risk with URD HCT (HR = 0.43, P = 0.01).

CONCLUSIONS

Our findings do not provide support for the preferential use of HCT over chemotherapy alone for children with cytogenetically defined poor-risk AML in CR1.

Rifaximin for preventing acute graft-versus-host disease: impact on plasma markers of inflammation and T-cell activation

In murine allogeneic hematopoietic cell transplantation models, inhibiting bacterial translocation stemming from conditioning-induced damage to the gut mucosa abrogates inflammatory stimulation of donor T cells, preventing acute graft-versus-host disease (AGVHD). We conducted a phase I trial to begin testing the hypothesis that rifaximin, a broadly acting oral antibiotic, would reduce systemic inflammation and T-cell activation. We administered rifaximin to 20 adolescents and younger adults (day -10 through day +30) receiving intensive conditioning. We measured the plasma level of interleukin-6, as a marker of conditioning-induced inflammation, and the levels of soluble tumor necrosis factor receptor-1 and soluble interleukin-2 receptor, as surrogate markers of AGVHD. We formed a historical control group (n=24), from a previous study of biomarkers in AGVHD. The increase in the treatment group's mean interleukin-6 level from baseline to day 0 was 73% less than that in the control group (P=0.006). The increase from baseline to day 15 in the treatment group's mean soluble tumor necrosis factor-1 and soluble interleukin-2 receptor levels was similar to the control group. Incidences of grade 2 to 4 AGVHD also did not differ. This suggests that rifaximin may abrogate bacterial translocation and resultant inflammation, but in alternative donor transplants this does not prevent downstream activation of donor T cells.

Outcome of transplantation for acute myelogenous leukemia in children with Down syndrome

Data on outcomes of allogeneic transplantation in children with Down syndrome and acute myelogenous leukemia (DS-AML) are scarce and conflicting. Early reports stress treatment-related mortality as the main barrier; a recent case series points to posttransplantation relapse. We reviewed outcome data for 28 patients with DS-AML reported to the Center for International Blood and Marrow Transplant Research between 2000 and 2009 and performed a first matched-pair analysis of 21 patients with DS-AML and 80 non-DS AML controls. The median age at transplantation for DS-AML was 3 years, and almost half of the cohort was in second remission. The 3-year probability of overall survival was only 19%. In multivariate analysis, adjusting for interval from diagnosis to transplantation, risks of relapse (hazard ratio [HR], 2.84; P < .001; 62% versus 37%) and transplant-related mortality (HR, 2.52; P = .04; 24% versus 15%) were significantly higher for DS-AML compared to non-DS AML. Overall mortality risk (HR, 2.86; P < .001; 21% versus 52%) was significantly higher for DS-AML. Both transplant-related mortality and relapse contribute to higher mortality. Excess mortality in DS-AML patients can only effectively be addressed through an international multicenter effort to pilot strategies aimed at lowering both transplant-related mortality and relapse risks.

Reducing the risk for transplantation-related mortality after allogeneic hematopoietic cell transplantation: how much progress has been made?

PURPOSE

Transplantation-related mortality (TRM) is a major barrier to the success of allogeneic hematopoietic cell transplantation (HCT).

PATIENTS AND METHODS

We assessed changes in the incidence of TRM and overall survival from 1985 through 2004 in 5,972 patients younger than age 50 years who received myeloablative conditioning and HCT for acute myeloid leukemia (AML) in first complete remission (CR1) or second complete remission (CR2).

RESULTS

Among HLA-matched sibling donor transplantation recipients, the relative risks (RRs) for TRM were 0.5 and 0.3 for 2000 to 2004 compared with those for 1985 to 1989 in patients in CR1 and CR2, respectively (P < .001). The RRs for all causes of mortality in the latter period were 0.73 (P = .001) and 0.60 (P = .005) for the CR1 and CR2 groups, respectively. Among unrelated donor transplantation recipients, the RRs for TRM were 0.73 (P = .095) and 0.58 (P < .001) for 2000 to 2004 compared with those in 1990 to 1994 in the CR1 and CR2 groups, respectively. Reductions in mortality were observed in the CR2 group (RR, 0.74; P = .03) but not in the CR1 group.

CONCLUSION

Our results suggest that innovations in transplantation care since the 1980s and 1990s have reduced the risk of TRM in patients undergoing allogeneic HCT for AML and that this reduction has been accompanied by improvements in overall survival.

Risk factors affecting outcome of second HLA-matched sibling donor transplantations for graft failure in severe acquired aplastic anemia

We examined transplantation outcomes after a second HLA-matched sibling transplantation for primary (16%) or secondary (84%) graft failure in 166 patients with severe acquired aplastic anemia (AA). Two-thirds of these patients has a performance score < 90. In most cases (88%), the same donor was used for both transplants, for both transplantations, and 84% of the second transplantations used bone marrow grafts. We identified 2 prognostic factors: intertransplantation interval (surrogate for primary graft failure and early secondary graft failure) and performance status. Shorter intertransplantation interval (<or= 3 months) and poor performance score (< 90) at second transplantation were associated with high mortality. In patients with a performance score of 90% to 100%, the 8-year probability of overall survival (OS) after second transplantation <or= 3 and > 3 months from first transplantation was 56% and 76%, respectively. The corresponding probabilities in patients with lower performance scores were 33% and 61%. The predominant cause of failure after second transplantation was nonengraftment (in 72 of 166 patients), most commonly in patients with primary or early secondary graft failure (51 of 72; 71%). Our data indicate that novel approaches, including conditioning regimens with greater immunosuppression, should be explored for these patients.

Impact of disease risk on efficacy of matched related bone marrow transplantation for pediatric acute myeloid leukemia: the Children's Oncology Group

PURPOSE

There is considerable variation in the use of HLA-matched related bone marrow transplantation (BMT) for the treatment of pediatric patients with newly diagnosed acute myeloid leukemia (AML). Some oncologists have argued that BMT should be offered to most patients in first complete remission (CR). Others have maintained that transplantation in first remission should be reserved for patients with high-risk disease. We performed this study to determine how disease risk influences the efficacy of BMT.

METHODS

We combined data from four cooperative group clinical trials: Pediatric Oncology Group 8821, Children's Cancer Group (CCG) 2891, CCG 2961, and Medical Research Council 10. Using cytogenetics and the percentage of marrow blasts after the first course of chemotherapy, patients were stratified into favorable, intermediate, and poor-risk disease groups. Patients who could not be risk classified were analyzed separately. Outcomes for patients assigned to BMT and for patients assigned to chemotherapy alone were compared.

RESULTS

The data set included 1,373 pediatric patients with AML in first CR. In the intermediate-risk group, the estimated disease-free survival at 8 years for patients who did not undergo transplantation was 39% +/- 5% (2 SE), whereas it was 58% +/- 7% for BMT patients. The estimated overall survival for patients who did not undergo transplantation was 51% +/- 5%, whereas it was 62% +/- 7% for BMT patients. Both differences were significant (P < .01). There were no significant differences for survival in the other two risk groups or in the non-risk-stratified patients.

CONCLUSION

Our study indicates that HLA-matched related BMT is an effective treatment for pediatric patients with intermediate-risk AML in first CR.

A Comparison of Cyclophosphamide and Total Body Irradiation with Etoposide and Total Body Irradiation as Conditioning Regimens for Patients Undergoing Sibling Allografting for Acute Lymphoblastic Leukemia in First or Second Complete Remission

We compared the outcomes of 298 patients with acute lymphoblastic leukemia in first or second complete remission (CR1 or CR2) receiving HLA-matched sibling allografts after cyclophosphamide and total body irradiation (Cy-TBI) conditioning with 204 patients receiving etoposide and TBI. Consequently, 4 groups were compared: Cy-TBI <13 Gy (n = 217), Cy-TBI > or =13 Gy (n = 81), etoposide-TBI <13 Gy (n = 53), and etoposide-TBI > or =13 Gy (n = 151). Analyses of relapse, leukemia-free survival (LFS), and survival were performed separately for CR1 and CR2 transplantations. Transplant-related mortality did not differ by conditioning regimen. In CR1, there were also no significant differences in relapse, LFS, or survival by conditioning regimen. In CR2, these outcomes differed among conditioning groups. In comparison with Cy-TBI <13 Gy, the risks of relapse, treatment failure (inverse of LFS), and mortality tended to be lower with etoposide (regardless of TBI dose) or with TBI doses > or =13 Gy. For both CR1 and CR2 transplantations, causes of death were similar among the groups; disease recurrence accounted for 47% of deaths. We conclude that for HLA-identical sibling allografts for acute lymphoblastic leukemia in CR2, there is an advantage in substituting etoposide for Cy or, when Cy is used, in increasing the TBI dose to > or =13 Gy.

Immunization to minor histocompatibility antigens on transfused RBCs through crosspriming into recipient MHC class I pathways

Increased rates of graft rejection after bone marrow transplantation (BMT) are observed in patients whose illnesses— such as sickle cell disease, thalassemia, and aplastic anemia—necessitate chronic transfusion before BMT. Because BM transplants in these patients are routinely HLA matched, any immunization responsible for increased rejection is likely against minor histocompatibility antigens (mHAs). It has been assumed that contaminating leukocytes in red blood cell (RBC) units are the main sources of immunization to mHAs. However, in this report, we demonstrate that antigens on donor RBCs are presented in the major histocompatibility complex (MHC) class I pathway of recipient antigen-presenting cells, resulting in activation and expansion of recipient CD8+ T cells specific for donor mHAs. Given that human hematopoietic progenitor cells express many of the known mHAs, this observation provides a mechanism by which chronic transfusion of even stringently leukoreduced RBCs may result in sufficient mHA immunization to increase the frequency of BMT rejection.

Busulfan/melphalan/antithymocyte globulin followed by unrelated donor cord blood transplantation for treatment of infant leukemia and leukemia in young children: the Cord Blood Transplantation study (COBLT) experience

A non-total body irradiation-containing preparative regimen was studied in young children (<4 years old) undergoing unrelated donor cord blood transplantation as part of the Cord Blood Transplantation trial for the treatment of acute lymphoblastic leukemia (n = 14), acute myeloid leukemia (n = 13), undifferentiated leukemia (n = 1), juvenile myelomonocytic leukemia (n = 2), and myelodysplastic syndromes (n = 2). Donor/recipient HLA matching based on low-/intermediate-resolution molecular typing for HLA-A and -B and high-resolution HLA-DRB1 typing was 5/6 or 6/6 (n = 21) or 4/6 (n = 11). The preparative therapy consisted of busulfan, melphalan, and antithymocyte globulin, with cyclosporine and corticosteroids for graft-versus-host disease (GVHD) prophylaxis. The median age was 1.6 years (range, 0.5-3.9 years), and the median weight was 10.5 kg (range, 5.8-19.5 kg). Cord blood grafts contained a median of 10.7 x 10 7 nucleated cells per kilogram (range, 4.6-29.2) and 2.6 x 10(5) CD34+ cells per kilogram (range, 0.7-8.3). The cumulative incidence (CINC) of neutrophil recovery (absolute neutrophil count >500/microL) at day 42 was 0.59 (95% confidence interval [CI], 0.44-0.78) at a median of 31 days (range, 23-55 days). The CINC and Kaplan-Meier estimates of platelet engraftment at day 180 were 0.53 (95% CI, 0.34-0.69) and 0.82 (95% CI, 0.61-1.00), respectively. CINC estimates of grade III/IV acute GVHD at day 100 and chronic GVHD at 1 year were 0.25 (95% CI, 0.09-0.41) and 0.26 (95% CI, 0.09-0.44), respectively. The CINC estimate of relapse was 0.31 (95% CI, 0.16-0.47) at 2 years. With a median follow-up of 27.8 months (range, 23.4-46.7 months), the probability of survival at 1 year was 0.47 (95% CI, 0.30-0.64). A preparative regimen containing a busulfan/melphalan/antithymocyte globulin preparative regimen is well tolerated in the setting of unrelated donor cord blood transplantation for childhood leukemia and can serve as a platform preparative regimen for intensifying host immunosuppression and antileukemic therapy to allow for improved engraftment and improved relapse-free survival.

Hematopoietic stem cell transplantation for multiply transfused patients with sickle cell disease and thalassemia after low-dose total body irradiation, fludarabine, and rabbit anti-thymocyte globulin

Patients with sickle cell disease (N = 3) and thalassemia (N = 1) with high-risk features received hematopoietic stem cell transplantations (HCT) to induce stable (full or partial) donor engraftment. Patients were 9-30 years of age. Fludarabine, rabbit anti-thymocyte globulin (ATG), and 200 cGy total body irradiation were administered pre-transplant. Patients received bone marrow (N = 3) or peripheral blood stem cells (N = 1) from HLA-identical siblings, followed by mycophenolate mofetil and cyclosporine for post-grafting immunosuppression. Significant lymphopenia, but only moderate neutropenia and thrombocytopenia developed post transplant. No grade IV nonhematological toxicities or acute graft-versus-host disease (GVHD) were observed. At 3 months after transplantation, three of four patients had evidence of donor myeloid chimerism (range, 15-100%). However, after post transplant immunosuppression was discontinued, graft rejection occurred in all but one patient. This patient is now doing well 27 months post transplant with full donor engraftment. One patient died after a second transplant, and another patient experienced a stroke as her graft was being rejected. These results suggest that stable donor engraftment after nonmyeloablative HCT is difficult to achieve among immunocompetent patients with hemoglobinopathies and that new approaches will need to be developed before wider application of this transplantation method for hemoglobinopathies.

Survival after HLA-identical allogeneic peripheral blood stem cell and bone marrow transplantation for hematologic malignancies: meta-analysis of randomized controlled trials

The impact of peripheral blood stem cell transplantation (PBSCT) on survival relative to bone marrow transplantation (BMT) remains poorly defined. Several randomized controlled trials (RCTs) comparing HLA-matched related PBSC- and BMT for patients with hematologic malignancies have been published, yielding differing results. We conducted a meta-analysis of published RCTs to more precisely estimate the effect of PBSCT on survival. Seven trials that assessed survival were identified and included in our analysis. Using a fixed effects model, and combining the results of all seven trials, the summary odds ratio for mortality after PBSCT was 0.81 (95% CI, 0.62-1.05) when compared to BMT. Subgroup analysis revealed no association between the median PBSCT 34+ cell dose and relative risk for morality after PBSCT. However, there was an association between the proportion of patients enrolled with advanced-stage disease and the summary odds ratio for mortality. The pooled estimate was 0.64 for studies where patients with intermediate/advanced disease comprised at least 25% of enrollment, and was 1.07 for the studies enrolling a smaller proportion. This finding substantiates results from previously published studies that have demonstrated a survival advantage with PBSCT limited to patients with advanced disease.

Fibrin degradation products, fibrin monomer and soluble fibrin in disseminated intravascular coagulation

Disseminated intravascular coagulation (DIC) is characterized by activation of hemostasis and fibrinolysis resulting in the formation of thrombin and plasmin, and the characteristic effects of these enzymes on plasma fibrinogen can be useful in diagnosis. Thrombin cleaves fibrinopeptides from fibrinogen, forming fibrin monomer that rapidly polymerizes to form a clot. Small amounts can circulate in plasma as "soluble fibrin," which may have a complex composition and include fibrinogen and a variable amount of cross-linking. Plasmic degradation of cross-linked fibrin forms a heterogeneous group of degradation products reactive in assays for D-dimer, and their levels provide a measure of the amount of fibrin formation and lysis. Caution should be exercised in comparing quantitative results using different assays because of problems with standardization and variable reactivity with different molecular forms. Marked elevations of fibrin(ogen) degradation products are a constant finding in experimental animal models of DIC. In human models of DIC resulting from endotoxin infusion, D-dimer is elevated early and high levels persist, reflecting lysis of microvascular fibrin deposits. Elevated levels of D-dimer and soluble fibrin are very sensitive for the diagnosis of DIC, and a normal level has a high negative predictive value. Serial monitoring of soluble fibrin or D-dimer assays may be of value in evaluating the response to therapy and possibly in identifying at-risk patients.

Prothrombotic changes in hemostatic parameters and C-reactive protein in the elderly with winter acute respiratory tract infections

Mortality rates attributable to cerebrovascular and ischemic heart disease increase among older adults during the winter. Prothrombotic changes in the hemostatic system related to seasonal factors, such as ambient temperature changes, and winter acute respiratory tract infections, may contribute to this excess seasonal mortality. A prospective nested case-control study was conducted to assess the impact of winter acute respiratory tract infections on fibrinogen, factor VII, factor VIIa, D-dimer, prothrombin fragment 1.2, PAI-1, soluble P-selectin and C-reactive protein (CRP) in older adults. The change in laboratory parameters from baseline (fall) to the time of infection in both middle-aged and elderly individuals was compared with matched non-infected controls. In older adult participants with winter acute respiratory tract infections, significant increases occurred in fibrinogen and C-reactive protein, but not in any other markers. The mean fibrinogen increased 1.52 g/L (38%) and the mean CRP increased 37 mg/L (370%) over baseline (both p <0.001). In a multivariate analysis, both infection and season were associated with the increase in fibrinogen, but only infection was associated with the CRP increase. Old age magnified the increase in CRP but not in fibrinogen. Winter acute respiratory tract infections induce an exaggerated inflammatory response in older adults. The associated increase in fibrinogen, an independent risk factor for ischemic heart disease, may be partly responsible for the excess winter vascular mortality.

Allogeneic bone marrow transplantation for children with acute leukemia: cytoreduction with fractionated total body irradiation, high-dose etoposide and cyclophosphamide

Marrow-ablative chemo-radiotherapy followed by hematopoietic stem cell rescue from an allogeneic source improves outcomes for children with high-risk acute leukemia. The first effective pre-transplant preparative regimens consisted of high-dose cyclophosphamide (CY) and total body irradiation (TBI). Subsequent attempts have been made to improve leukemia-free survival, by adding other chemotherapy agents to these agents. In previous clinical studies of total body irradiation, etoposide, cyclophosphamide (TBI-VP-16-Cy) in adult allogeneic bone marrow transplantation, there has been a high incidence of severe regimen-related toxicity. In this study, we investigated the safety and efficacy of this combination in 41 children who received TBI (12-14 Gy), VP-16 (30 mg/kg), and CY (60 mg/kg x 2) and then either matched sibling or alternative donor transplants for acute leukemia. There was only one case of fatal regimen-related toxicity. The estimated 3-year event-free survival for patients with early or intermediate stage disease was 68% (53-88%). The estimated event-free survival of patients with advanced disease was 17% (5-59%). TBI-VP16-CY is safe in pediatric transplantation, and it has good efficacy for transplant recipients with less advanced disease. Bone Marrow Transplantation (2000) 25, 489-494.

Automated latex agglutination and ELISA testing yield equivalent D-dimer results in patients with recent myocardial infarction. THROMBO Research Investigators

Our previous prospective study of post-infarction patients described a strong and significant association of increased plasma D-dimer concentrations in those who experienced a subsequent coronary death or non-fatal myocardial infarction. In the present study, we compare results on stored plasma obtained two months after the index myocardial infarction from 1,038 patients of this trial, using a simple automated latex agglutination (LA) assay in parallel with the standard ELISA test. Results show a somewhat higher mean value for the LA assay (702+/-1092 vs. 638+/-986 ng/ml, p = 0.0002), a strong linear correlation of the two assays (r = 0.86) and 88% agreement for values below 500 ng/ml by the ELISA test. D-dimer concentrations determined by each assay were highly correlated in patients with subsequent coronary artery events (p = 0.93) and quartile values for both the LA and ELISA were equally predictive of such events (p = 0.003 and p = 0.001, respectively). This is the first demonstration that a latex agglutination assay for D-dimer can be used to assess the prognostic risk of recurrent coronary thrombotic disease after myocardial infarction

Exposure to nicotine enhances acquisition of ethanol drinking by laboratory rats in a limited access paradigm

Observations in humans suggest that the initial use of tobacco occurs in close temporal proximity to experimentation with alcohol. There have been relatively few research reports, however, examining possible interactions between these two agents. The present experiments examined the effect of nicotine exposure on the acquisition of ethanol drinking behavior in a limited access procedure. In experiment 1, rats were presented with 1-h access to ethanol solutions of increasing concentration for a period of 20 days. Subcutaneous injections of nicotine (0.6 or 1.2 mg/kg salt) or vehicle were administered 30 min prior to each ethanol presentation. Experiment 2 used a similar method, but rats were presented with water along with ethanol during the 1-h test session. Mecamylamine, a nicotinic receptor antagonist, was administered 30 min prior to the nicotine treatment. Nicotine was seen to produce a dose-dependent increase in ethanol drinking behavior which commenced at the 5% ethanol concentration and continued at 8% and again at 10%. In the second experiment, mecamylamine was observed to block completely the nicotine-induced increase in ethanol drinking behavior. The findings suggest that exposure to nicotine can facilitate the acquisition of ethanol drinking behavior in naive rats and that this effect is mediated by nicotine's interaction at the nicotinic-cholinergic receptor.