Myeloablative Hematopoietic Cell Transplantation Research Articles

Cognitive Functioning After Hematopoietic Cell Transplantation for Hematologic Malignancy: Results From a Prospective Longitudinal Study.

Purpose Cognitive impairment is well-recognized after myeloablative allogeneic hematopoietic cell transplantation (HCT). However, cognitive functioning after reduced-intensity allogeneic or autologous HCT remains unclear. Methods A total of 477 HCT recipients (236 autologous, 128 reduced-intensity allogeneic, 113 myeloablative allogeneic) underwent standardized neuropsychologic testing before HCT and at 6 months and 1, 2, and 3 years after HCT. Ninety-nine frequency-matched healthy controls underwent testing at commensurate time points. Primary outcomes of the study were practice effect-adjusted domain-specific T scores and global deficit scores. Piecewise generalized estimating equation models were used to compare groups and to identify associated variables and post-HCT trends of cognitive impairment. Results Median age was 52 years (range, 18 to 74 years) for HCT recipients and 55 years (range, 19 to 73 years) for controls. Post-HCT scores were comparable between controls and autologous and reduced-intensity HCT recipients. Myeloablative HCT recipients had significantly lower ( P < .001) post-HCT scores than controls for executive function, verbal speed, processing speed, auditory memory, and fine motor dexterity. Pre-HCT to 6 months post-HCT scores did not change after reduced-intensity HCT but declined significantly for fine motor dexterity ( P < .001) after myeloablative HCT. However, pre-HCT to 3 years post-HCT scores declined significantly ( P < .003) in reduced-intensity HCT recipients for executive function, verbal fluency, and working memory. Older age, male sex, and lower education, income, and cognitive reserve were associated with post-HCT cognitive impairment. At 3 years post-HCT, global cognitive impairment was present in 18.7% of autologous and 35.7% of allogeneic HCT recipients. Conclusion Myeloablative allogeneic HCT recipients showed significant cognitive decline compared with healthy controls. Reduced-intensity allogeneic HCT recipients showed evidence of delayed decline. Cognitive functioning in autologous HCT recipients generally was spared. The study identified vulnerable subpopulations that could benefit from targeted interventions.

Risk factors for post-transplant lymphoproliferative disorder after Thymoglobulin-conditioned hematopoietic cell transplantation.

Epstein-Barr virus (EBV)-induced post-transplant lymphoproliferative disorder (PTLD) occurs frequently when rabbit antithymocyte globulin (ATG) is used in hematopoietic cell transplant (HCT) conditioning. We retrospectively studied 554 patients undergoing ATG-conditioned myeloablative HCT. Strategies used to minimize mortality due to PTLD were either therapy of biopsy-diagnosed PTLD in the absence of EBV DNAemia monitoring (n=266) or prompt therapy of presumed PTLD (based on clinical/radiologic signs and high EBV DNAemia, in the setting of weekly EBV DNAemia monitoring) (n=199). Both strategies resulted in similar mortality due to PTLD (0.7% vs 1% at 2years, P=.43) and similar overall survival (63% vs 67% at 2years, P=.23) even though there was a trend toward higher PTLD incidence with the prompt therapy. Donor positive with recipient negative EBV (D+R-) serostatus was a risk factor for developing PTLD. Older patient age, HLA-mismatched donor, and graft-versus-host disease were not associated with increased risk of PTLD. In summary, in ATG-conditioned HCT, D+R- serostatus, but not older age, mismatched donor or GVHD is a risk factor for developing PTLD. EBV DNAemia monitoring may be a weak risk factor for developing/diagnosing PTLD; the monitoring coupled with prompt therapy does not improve survival.

Vorinostat plus tacrolimus/methotrexate to prevent GVHD after myeloablative conditioning, unrelated donor HCT

AbstractThe oral histone deacetylase (HDAC) inhibitor (vorinostat) is safe and results in low incidence of acute graft-versus-host disease (GVHD) after reduced-intensity conditioning, related donor hematopoietic cell transplantation (HCT). However, its safety and efficacy in preventing acute GVHD in settings of heightened clinical risk that use myeloablative conditioning, unrelated donor (URD), and methotrexate are not known. We conducted a prospective, phase 2 study in this higher-risk setting. We enrolled 37 patients to provide 80% power to detect a significant difference in grade 2 to 4 acute GVHD of 50% compared with a reduction in target to 28%. Eligibility included adults with a hematological malignancy to receive myeloablative HCT from an available 8/8-HLA matched URD. Patients received GVHD prophylaxis with tacrolimus and methotrexate. Vorinostat (100 mg twice daily) was started on day −10 and continued through day +100 post-HCT. Median age was 56 years (range, 18-69 years), and 95% had acute myelogenous leukemia or high-risk myelodysplastic syndrome. Vorinostat was safe and tolerable. The cumulative incidence of grade 2 to 4 acute GVHD at day 100 was 22%, and for grade 3 to 4 it was 8%. The cumulative incidence of chronic GVHD was 29%; relapse, nonrelapse mortality, GVHD-free relapse-free survival, and overall survival at 1 year were 19%, 16%, 47%, and 76%, respectively. Correlative analyses showed enhanced histone (H3) acetylation in peripheral blood mononuclear cells and reduced interleukin 6 (P = .028) and GVHD biomarkers (Reg3, P = .041; ST2, P = .002) at day 30 post-HCT in vorinostat-treated subjects compared with similarly treated patients who did not receive vorinostat. Vorinostat for GVHD prevention is an effective strategy that should be confirmed in a randomized phase 3 study. This trial was registered at www.clinicaltrials.gov as #NCT01790568.

Graft-Derived Reconstitution of Mucosal-Associated Invariant T Cells after Allogeneic Hematopoietic Cell Transplantation

Mucosal-associated invariant T (MAIT) cells express a semi-invariant Vα7.2+ T cell receptor (TCR) that recognizes ligands from distinct bacterial and fungal species. In neonates, MAIT cells proliferate coincident with gastrointestinal (GI) bacterial colonization. In contrast, under noninflammatory conditions adult MAIT cells remain quiescent because of acquired regulation of TCR signaling. Effects of inflammation and the altered GI microbiota after allogeneic hematopoietic cell transplantation (HCT) on MAIT cell reconstitution have not been described. We conducted an observational study of MAIT cell reconstitution in myeloablative (n = 41) and nonmyeloablative (n = 66) allogeneic HCT recipients and found that despite a rapid and early increase to a plateau at day 30 after HCT, MAIT cell numbers failed to normalize for at least 1 year. Cord blood transplant recipients and those who received post-HCT cyclophosphamide for graft versus host disease (GVHD) prophylaxis had profoundly impaired MAIT cell reconstitution. Sharing of TCRβ gene sequences between MAIT cells isolated from HCT grafts and blood of recipients after HCT showed early MAIT cell reconstitution was due at least in part to proliferation of MAIT cells transferred in the HCT graft. Inflammatory cytokines were required for TCR-dependent MAIT cell proliferation, suggesting that bacterial Vα7.2+ TCR ligands might promote MAIT cell reconstitution after HCT. Robust MAIT cell reconstitution was associated with an increased GI abundance of Blautia spp. MAIT cells suppressed proliferation of conventional T cells consistent with a possible regulatory role. Our data identify modifiable factors impacting MAIT cell reconstitution that could influence the risk of GVHD after HCT.

Survival and Late Effects after Allogeneic Hematopoietic Cell Transplantation for Hematologic Malignancy at Less than Three Years of Age

Very young children undergoing hematopoietic cell transplantation (HCT) are a unique and vulnerable population. We analyzed outcomes of 717 patients from 117 centers who survived relapse free for ≥1 year after allogeneic myeloablative HCT for hematologic malignancy at <3 years of age, between 1987 and 2012. The median follow-up was 8.3 years (range, 1.0 to 26.4 years); median age at follow-up was 9 years (range, 2 to 29 years). Ten-year overall and relapse-free survival were 87% (95% confidence interval [CI], 85% to 90%) and 84% (95% CI, 81% to 87%). Ten-year cumulative incidence of relapse was 11% (95% CI, 9% to 13%). Of 84 deaths, relapse was the leading cause (43%). Chronic graft-versus-host-disease 1 year after HCT was associated with increased risk of mortality (hazard ratio [HR], 2.1; 95% CI, 1.3 to 3.3; P = .0018). Thirty percent of patients experienced ≥1 organ toxicity/late effect >1 year after HCT. The most frequent late effects included growth hormone deficiency/growth disturbance (10-year cumulative incidence, 23%; 95% CI, 19% to 28%), cataracts (18%; 95% CI, 15% to 22%), hypothyroidism (13%; 95% CI, 10% to 16%), gonadal dysfunction/infertility requiring hormone replacement (3%; 95% CI, 2% to 5%), and stroke/seizure (3%; 95% CI, 2% to 5%). Subsequent malignancy was reported in 3.6%. In multivariable analysis, total body irradiation (TBI) was predictive of increased risk of cataracts (HR, 17.2; 95% CI, 7.4 to 39.8; P < .001), growth deficiency (HR, 3.5; 95% CI, 2.2 to 5.5; P < .001), and hypothyroidism (HR, 5.3; 95% CI, 3.0 to 9.4; P < .001). In summary, those who survived relapse free ≥1 year after HCT for hematologic malignancy at <3 years of age had favorable overall survival. Chronic graft-versus-host-disease and TBI were associated with adverse outcomes. Future efforts should focus on reducing the risk of relapse and late effects after HCT at early age.

Evaluation of the Pharmacokinetics and Efficacy of a Busulfan Test Dose in Adult Patients Undergoing Myeloablative Hematopoietic Cell Transplantation

Owing to interpatient variability in busulfan exposure, therapeutic monitoring of busulfan is often used in myeloablative allogeneic transplantation to ensure that patients are near the optimal steady-state goal of 900 ng/mL. One challenge in therapeutic monitoring of busulfan is the brief course of busulfan treatment, requiring prompt analysis and dose adjustments as needed. Pharmacokinetic evaluation of a busulfan test dose before the start of the conditioning regimen would allow for all conditioning regimen doses to be given at the calculated optimized dose. An observational study was completed to evaluate the effects of a busulfan test dose of 0.9 mg/kg administered before the start of a myeloablative intravenous busulfan-based conditioning regimen. Sixty adult patients who received a busulfan conditioning regimen were reviewed, including 30 patients prior to the implementation of the busulfan test dose (pretest dose group) and 30 patients who received the busulfan test dose (posttest dose group). The primary objective was a pharmacokinetic evaluation of the percentage of patients who achieved the desired steady-state goal using the test dose strategy. The safety and efficacy of the busulfan test dose were evaluated as well. The average busulfan steady-state level after the first dose of the conditioning regimen was significantly lower in the pre-test dose group compared with the post-test dose group (660 ng/mL versus 879.9 ng/mL; P < 0.001). Compared with the post-test dose group, significantly fewer patients in the pre-test dose group were within 10% of the busulfan steady-state goal (10% versus 73.3%; P < 0.001) or within 5% of the goal (0% versus 53%; P < 0.001). Requirements for parenteral nutrition and/or patient-controlled analgesia owing to mucositis and rates of veno-occlusive disease were not significantly different between the pre-test dose group and the post-test dose group. The rates of disease relapse, mortality, and acute graft-versus-host disease were similar in the two groups. A pretransplantation busulfan test dose of 0.9 mg/kg improved the patients' ability to reach therapeutic busulfan target levels after the first conditioning dose and resulted in fewer adjustments during conditioning. The use of a busulfan test dose did not significantly increase patients' risk of mucositis or other safety outcomes.

Should patients with acute myeloid leukemia and measurable residual disease be transplanted in first complete remission?

Measurable ('minimal') residual disease in acute myeloid leukemia during first complete morphologic remission (MRD CR1) identifies patients with particularly high relapse risk and short survival. Here, we examine the evidence regarding optimal postremission treatment strategy for such patients. With chemotherapy alone or chemotherapy/autologous hematopoietic cell transplantation (HCT), disease recurrence appears inevitable in patients with MRD CR1. Nonrandomized studies indicate that allogeneic HCT improves outcomes over chemotherapy and/or autologous HCT, although relapse risks remain substantial. Emerging data suggest that myeloablative cord blood HCT may overcome the negative impact of MRD to a greater degree than other transplants, but the relative contributions of intensified conditioning and stem cell source to this effect are unknown. Available evidence supports the recommendation to consider allogeneic HCT for all acute myeloid leukemia patients in MRD CR1. Whether cord blood transplants should be prioritized deserves further investigation. To what degree outcomes of MRD CR1 patients could be improved by treatment intensification during induction, postremission therapy and/or before transplantation to revert the patient into an MRD state is currently unknown, as is the value of post-transplant preemptive therapies. These remain areas worthy of investigation, preferably in the setting of controlled clinical trials.

212 - Impact of Anti- T Lymphocyte Globulin (ATLG) on Immune Reconstitution in Patients Undergoing HLA Matched Unrelated Myeloablative Hematopoietic Cell Transplantation (HCT): Results From a Prospective Randomized Double Blind Phase 3 Clinical Trial

212 - Impact of Anti- T Lymphocyte Globulin (ATLG) on Immune Reconstitution in Patients Undergoing HLA Matched Unrelated Myeloablative Hematopoietic Cell Transplantation (HCT): Results From a Prospective Randomized Double Blind Phase 3 Clinical Trial

Prognostic Effect of Bone Marrow (BM) and Peripheral Blood Stem Cell (PBSC) Donor Cell Subsets on Myeloablative Allogeneic Hematopoietic Cell Transplantation (HCT) Outcomes

Allogeneic HCT is a crucial tool for the treatment of hematologic malignancies, immune-deficiencies, and metabolic disorders. Donor-derived T-cells are critical for the graft-versus-leukemia effect, assist in engraftment, and protect against infections; however, they are also involved in the development of graft-versus-host-disease (GVHD). Although total nucleated cell (TNC) dose and CD34 cell doses have previously been correlated with post-transplant outcomes, there are limited data on the role of donor T-cell subsets in engraftment and post-HCT complications including GVHD. We examined the association of donor cell subset data with outcomes in myeloablative allogeneic HCT recipients from 2002 to 2014 in our single-center retrospective cohort study.Analysis was restricted to recipients of BM (N=359) or G-CSF mobilized PBSC (N=61) grafts from HLA-identical sibling and unrelated donors. Total nucleated cell (TNC), CD34, CD3, CD4, CD8, and CD56 (PBSC only) doses from the pre-infusion graft were analyzed for association with disease and outcome data prospectively collected by our institution’s HCT database. Multivariable Fine and Gray or Cox regression analyses adjusted for clinical variables and evaluated association of donor cell subset with the following outcomes: neutrophil engraftment (>500/uL x 3 days), platelet engraftment (>20,000/uL x 3 days), lymphocyte recovery (>500/uL x 1 day), any infection, donor chimerism (≥95% by day 100), grade 2-4 acute GVHD, chronic GVHD, non-relapse mortality (NRM) and overall survival. Analyses were performed separately for BM and PBSC groups.In the BM cohort, median recipient age was 47 years; 77% patients had acute leukemia/MDS; 58% had HLA-identical sibling donor. Most patients received ablative Bu-Cy (63%) or etoposide-TBI (19%) conditioning, with CNI-MMF (49%) or CNI-MTX (47%) as GVHD prophylaxis. Donor median age was 42 years and 39% were CMV positive. The mean graft (/kg) TNC and CD34 doses were 2.29x108 and 2.52x106, and mean T-cell subset doses were 32.19x108 CD3, 17.92x108 CD4, and 12.75x108 CD8, respectively. Among patients receiving a PBSC graft, median age was 48 years, 82% had acute leukemia/MDS, and 64% had an unrelated donor. Similar to BM, most patients received ablative Bu-Cy (67%) or etoposide-TBI (15%) conditioning, and CNI-MMF (33%) or CNI-MTX (61%) for GVHD prophylaxis. Median donor age was 40 years and 36% were CMV seropositive. The mean graft cell doses (/kg) were 9.51x108 TNC, 5.50x106 CD34, 2.74x108 CD3, 1.75x108 CD4, 0.88x108 CD8, and 0.36x108 CD56, respectively. Median time to neutrophil, lymphocyte and platelet recovery was 15, 27 and 23 days, respectively in the BM cohort, and 12, 19 and 16 days, respectively in the PBSC cohort. The table shows significant associations between donor cell subsets and post-HCT outcomes from the multivariable analysis.In summary, among myeloablative allogeneic HCT patients receiving BM grafts, earlier neutrophil engraftment was seen with higher TNC dose, while platelet engraftment and lymphocyte recovery was seen with higher CD34 dose. Among PBSC grafts, higher CD8 dose was associated with earlier lymphocyte recovery, higher CD4 dose with lower risk of infection, and higher CD34 dose with greater risk of acute GVHD but lower risk of NRM. The relative contribution of each donor cell subset between BM and PBSC grafts can impact outcomes. We did not observe any association of donor cell subsets with donor chimerism, chronic GVHD, or overall survival in this population. BM and PBSC graft composition can impact myeloablative allogeneic HCT outcomes and future studies to evaluate optimal graft composition are needed. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

A Small Molecule Inhibitor of Protein Tyrosine Phosphatase-Sigma (PTPσ) Promotes Hematopoietic Stem Cell (HSC) Regeneration

Receptor tyrosine kinases (RTKs), such as c-kit, Flt-3 and Tie2, regulate hematopoietic stem cell (HSC) proliferation, differentiation and maintenance. Substantially less is known regarding the function of receptor protein tyrosine phosphatases (PTPs) in regulating HSC fate. We recently discovered that receptor protein tyrosine phosphatase sigma (PTPσ) is highly expressed by murine and human HSCs. Interestingly, constitutive deletion of PTPσ caused a marked increase in HSC repopulating capacity as measured in primary and secondary competitive repopulation assays (J Clin Invest 2015;125:177-182). Further, negative selection of human cord blood (CB) HSCs for PTPσ surface expression (PTPσ - negative CB HSCs) conferred more than 10-fold increased human CB hematopoietic engraftment through 20 weeks in transplanted NSG mice. Additionally, PTPσ-deficient mice displayed significantly augmented recovery of phenotypic bone marrow (BM) HSCs and colony forming cells at day +10 following 550 cGy total body irradiation. Based on these observations, we hypothesized that PTPσ may function as a negative regulator of HSC self-renewal and regeneration. We sought to develop pharmacologic strategies to inhibit PTPσ function as a means to augment HSC functional capacity. Based on structure-activity-relationship analysis of PTPσ, we screened candidate small molecules for ability to modulate PTPσ function on BM HSCs. We identified a small molecule, 5483071 (Chembridge), as a candidate PTPσ inhibitor. In silico simulation indicated that 5483071 rigidly docked into the binding site of PTPσ intracellular domain through hydrogen bonding and electrostatic interactions. In a model of HSC injury and regeneration, we irradiated C57Bl6 mice with 700 cGy TBI and treated mice systemically with either 10 μcg of 5483071 or water subcutaneously every other day from day +1 to day +14. Irradiated mice treated with 5483071 displayed significantly increased 60 day survival compared to controls (P=0.0007). Irradiated mice treated with 5483071 showed accelerated recovery of BM SLAM+kit+sca-1+lin- HSCs (P=0.02), BM KSL cells (P=0.01), and colony forming cells (CFCs) (P=0.0003). In vitro culture of BM KSL cells with 5483071 significantly increased the levels of activated Rac1 (P=0.0004), which recapitulated the effects of PTPσ deletion on Rac1 activation in HSCs. Importantly, treatment of BM KSL cells from PTPσ -/- mice with 5483071 caused no change in Rac1 activation, suggesting that 5483071 acted specifically on PTPσ and was not mediating effects via inhibition of other phosphatases. Systemic administration of 5483071 to irradiated mice caused an increase in BM KSL cell cycling at 72 hours compared to irradiated control mice (p=0.02), while also decreasing BM KSL cell apoptosis at 24 hours after TBI (p=0.02). Subsequent to these findings, we have generated several new small molecule inhibitors of PTPσ with novel composition of matter and have taken a lead compound into pre-clinical studies for investigational new drug (IND) development. PTPσ represents a novel receptor tyrosine phosphatase that regulates HSC self-renewal and regeneration. Targeted inhibition of PTPσ has high therapeutic potential to promote hematopoietic regeneration in patients receiving myelosuppressive chemotherapy and/or radiotherapy or undergoing myeloablative hematopoietic cell transplantation. DisclosuresNo relevant conflicts of interest to declare.

A Prospective Randomized Double Blind Phase 3 Clinical Trial of Anti- T Lymphocyte Globulin (ATLG) to Assess Impact on Chronic Graft-Versus-Host Disease (cGVHD) Free Survival in Patients Undergoing HLA Matched Unrelated Myeloablative Hematopoietic Cell Transplantation (HCT)

A Prospective Randomized Double Blind Phase 3 Clinical Trial of Anti- T Lymphocyte Globulin (ATLG) to Assess Impact on Chronic Graft-Versus-Host Disease (cGVHD) Free Survival in Patients Undergoing HLA Matched Unrelated Myeloablative Hematopoietic Cell Transplantation (HCT)

Comparison of Total Body Irradiation-Based with Intravenous Busulfan-Based Chemotherapy-Only Conditioning Regimens for Myeloablative Hematopoietic Cell Transplantation (HCT) in Adults with Acute Lymphoblastic Leukemia

Total body irradiation (TBI)-based conditioning regimens are considered the standard of care for patients with acute lymphoblastic leukemia (ALL) undergoing allogeneic hematopoietic cell transplantation (HCT). However, due to concerns regarding acute and long-term toxicities, non-TBI regimens, commonly including busulfan (BU), have been increasingly explored. We performed a retrospective cohort analysis with the hypothesis that there would be equivalence of these two myeloablative approaches by reviewing outcomes for adult patients (pts), aged 18-60 years, undergoing a first, well-matched sibling, related or unrelated donor HCT in CR1 or CR2 reported to the Center for International Blood and Marrow Transplant Research (CIBMTR) from 2005-2014. Eight hundred nineteen pts received TBI (63% 9-12 Gy, 37% ≥13 Gy) combined with etoposide (25%) or cyclophosphamide (Cy) (75%) and 299 pts received intravenous BU combined with a second alkylator Cy (15%) or melphalan (Mel) (13%), or a nucleoside analogue fludarabine (Flu) (41%) or clofarabine (Clo)(30%). The majority of the BU-based pts were treated at the Moffitt or MD Anderson Cancer Center. The BU-based regimens were grouped together for analyses since no significant differences in basic outcomes among the different chemotherapy-only regimens were noted. Patients in the BU-containing group were older but had better performance status, took longer to achieve CR1 and longer to receive HCT; more received peripheral blood than marrow grafts, peri-HCT ATG, pre- and post HCT tyrosine kinase inhibitors ( TKI), and were treated more recently than pts in the TBI-based group (Table 1). With median follow-up of 3.6 years for the BU-based group and 5.3 years for the TBI-based group, adjusted 3 year outcomes showed treatment-related mortality (TRM) BU 19% vs. TBI 25% (p=.04); relapse BU 37% vs. TBI 28% (p=.007); disease-free survival (DFS) Bu 45% vs. TBI 48% (p=.35); and overall survival (OS) BU 57% vs. TBI 53% (p=.35) (Figures A-B). Patients in the BU group had significantly more grade II-IV acute GVHD (47% vs. 40%, p=.025), but marginally less chronic GVHD (49% vs. 55% at 3 years, p=.073). In multivariate analysis, the BU group had a significantly higher rate of acute GVHD after day 50 (RR 1.75, 95% CI 1.19-2.58, p=.004), but marginally less chronic GVHD (RR 0.83, 95% CI 0.68-1.01 p=.059) and higher risk of relapse (RR 1.46, 95% CI 1.15-1.85 p=.002) compared with TBI-based regimens. Despite the observed higher risks of acute GVHD and relapse, BU-based conditioning led to similar TRM, OS, and DFS following HCT for ALL. [Display omitted] [Display omitted] [Display omitted] DisclosuresCiurea:Spectrum Pharmaceuticals: Other: Advisory Board; Cyto-Sen Therapeutics: Equity Ownership. Seftel:Otsuka: Research Funding. Pulsipher:Medac: Other: Housing support for conference; Chimerix: Consultancy; Jazz Pharmaceutical: Consultancy; Novartis: Consultancy, Other: Study Steering Committee. Champlin:Ziopharm Oncology: Equity Ownership, Patents & Royalties; Intrexon: Equity Ownership, Patents & Royalties.

CD16+ Dendritic Cells Are a Unique Myeloid Antigen Presenting Cell Population

Dendritic cells (DC) are phenotypically identified in human blood as HLA-DR+ cells, which lack major cell surface lineage markers. We demonstrated that myeloid antigen presenting cells, including monocytes and DC display a continuum of CD14 and CD16 expression (10th Human Leucocyte Differentiation Antigen Workshop). The robustness of DC and monocyte identification, particularly when identifying cell subsets with little or no surface CD14 is limited by subjective gating strategies for determining rare cell populations. Application of Poisson counting statistics established that rare cell types such as "CD14- CD16+ DC" are often overlooked in analyses powered to detect the much larger populations of "classical" and "non-classical" monocytes.We used fluorescent and mass cytometry, in conjunction with unsupervised high dimensional clustering, to show that the continuum of CD14 expression separates CD14lo CD16+ non-classical monocytes and CD14- CD16+ DC. We have defined the CD14-CD16+ DC using a broad panel of cell surface markers and established a CD14-CD16+ DC phenotypic signature that is distinct from both classical and non-classical monocytes in healthy donor blood. The CD14-CD16+ DC differ in both size to CD14lo CD16+ monocytes and functional antigen uptake, with slower kinetics of soluble antigen uptake into lysozymes. Their proteasome processing and presentation of influenza matrix protein by MHC I was comparable to other primary blood monocytes and DC antigen presenting cell populations. The CD14-CD16+ DC had limited capacity for further in vitro differentiation. The recovery of CD14-CD16+ DC after autologous and allogeneic myeloablative hematopoietic cell transplants (HCT) followed similar kinetics to other monocytic and DC populations. CD14lo CD16+ monocytes expressed CCR5 as did other myeloid DC but CD14-CD16+ DC lacked CCR5, although interferon induced CCR5. The early differentiation and induction of CCR5 on circulating CD16+ DC after allogeneic HCT predicted for the onset of acute graft versus host disease.These data demonstrate that "CD14- CD16+ DC" represents a distinct clinically relevant human white blood cell population, whose ontogeny and function are under further investigation. DisclosuresFromm:DendroCyte BioTech Ltd: Other: Laboratory IP contracted via ANZAC Research Institute to DendroCyte BioTech Ltd. Papadimitrious:DendroCyte BioTech Ltd: Other: Laboratory IP contracted via ANZAC Research Institute to DendroCyte BioTech Ltd. Hsu:DendroCyte BioTech Ltd: Other: Laboratory IP contracted via ANZAC Research Institute to DendroCyte BioTech Ltd. Larsen:DendroCyte BioTech Ltd: Other: Laboratory IP contracted via ANZAC Research Institute to DendroCyte BioTech Ltd. Gibson:DendroCyte BioTech Ltd: Other: Laboratory IP contracted via ANZAC Research Institute to DendroCyte BioTech Ltd. Bradstock:DendroCyte BioTech Ltd: Other: Laboratory IP contracted via ANZAC Research Institute to DendroCyte BioTech Ltd. Kupresanin:DendroCyte BioTech Ltd: Other: Laboratory IP contracted via ANZAC Research Institute to DendroCyte BioTech Ltd. Clark:DendroCyte BioTech Ltd: Equity Ownership, Other: Laboratory IP contracted via ANZAC Research Institute to DendroCyte BioTech Ltd. Hart:DendroCyte BioTech Ltd: Equity Ownership, Other: Laboratory IP contracted via ANZAC Research Institute to DendroCyte BioTech Ltd.

Fludarabine and Busulfan Plus Low Dose TBI Versus Cyclophosphamide Plus TBI in Allogeneic Hematopoietic Cell Transplantation for Adult Acute Lymphoblastic Leukemia: Equivalent Outcomes in a Recent, Large Canadian Multicenter Cohort

Background: Allogeneic hematopoietic cell transplantation (HCT) is an important treatment for adults with acute lymphoblastic leukemia (ALL). The combination of cyclophosphamide with total body irradiation (TBI) at doses of 1200 to 1500 cGy (Cy/TBI1200) has been used in most prospective trials of HCT in ALL. However, TBI is associated with significant short and long term toxicities. Although Cy/TBI/1200 is the standard of care at most Canadian transplant centers one center instead prefers a conditioning regimen including fludarabine, busulfan, and low dose TBI (400 cGy) (Flu/Bu/TBI400) (Daly et al. BBMT 2012). We sought to compare the outcomes of HCT for adults with ALL who routinely received either Cy/TBI1200 or Flu/Bu/TBI400 as their conditioning regimen with the hypothesis that the regimens will result in similar outcomes. Conditioning regimen was highly correlated with transplant center, minimizing any selection bias in which clinicians might choose a regimen perceived to be of lower toxicity for selected patients.Methods: We included patients aged 18 or above who underwent a first myeloablative HCT for ALL in complete remission at one of three Canadian transplant centers from 2004-2014. Two of the centers use Cy/TBI1200 as a preferred conditioning regimen and the third center preferred Flu/Bu/TBI400. As the choice of conditioning regimen is strongly linked to transplant center we have performed an instrumental variable analysis in which the instrumental variable was the transplant center preference. Other transplant practices, including indications for transplant and supportive care, were similar between the centers. Overall survival (OS), progression-free survival (PFS), relapse rate (RR), and non-relapse mortality (NRM) were compared between groups.Results: A total of 146 patients were included, with 74 treated at centers that prefer Cy/TBI1200, of whom 72 received Cy/TBI1200 as conditioning, and 72 were treated at a Flu/Bu/TBI400 center, of whom 71 received Flu/Bu/TBI400. Importantly, no significant difference in transplant year, cytogenetic risk group, disease status at time of transplant, stem cell source, or graft versus host disease prophylaxis regimen was seen (Table 1). There were more patients with poor performance status in the Flu/Bu/TBI400 center (p = 0.004), and more ATG use in that centre (p < 0.001). In univariate analysis, there was no difference between centers in terms of OS and PFS (Figure 1). Similarly, in multivariable regression models there was no difference in either OS or PFS (Table 2). Cumulative incidence of non-relapse mortality was similar between groups (2 year point estimate of 12% in Cy/TBI1200 centers and 16.7% in the Flu/Bu/TBI400 centre, p=0.62). Cumulative incidence of relapse was lower in the Flu/Bu/TBI400 center (p = 0.05, 2 year point estimate of 31% in Cy/TBI centers and 18.5% in Flu/Bu/TBI 400 centers).Discussion: In this recently treated cohort of adults ALL with minimal selection bias, we demonstrate that similar rates of overall and progression free survival can be achieved with conditioning regimens that contain low doses of TBI. [Display omitted] [Display omitted] [Display omitted] DisclosuresDaly:Sanofi-Genzyme: Other: Advisory Board. Seftel:Otsuka: Research Funding.

Impact of Nutrition on Non-Relapse Mortality and Acute Graft Versus Host Disease during Allogeneic Hematopoietic Cell Transplantation for Hematologic Malignancies

The process of allogeneic hematopoietic cell transplantation (HCT) is often associated with poor oral intake and as a result, nutritional status declines. Although it might seem obvious that optimal nutrition is likely to improve outcomes of transplantation, there are no clinical data that directly support this assumption. It is also unclear whether artificial nutrition support (ANS) should be provided as enteral tube feeding (ETF) or parenteral nutrition (PN).In this study we analysed day 100 non-relapse mortality (NRM) and incidence and severity of acute graft versus host disease (GvHD) according to both the route and adequacy of nutritional intake together with other known prognostic factors. A total of 484 patients who underwent HCT for hematological malignancy at a single institution between 2000 and 2014 were included. Myeloablative conditioning was used in 285 (59%) patients, 272 of whom received a TBI based regimen. Reduced intensity conditioning was given to 199 (41%) patients. For the 236 (49%) unrelated donor cell recipients in vivo T-cell depletion with alemtuzumab was used. Myeloablative HCT recipients were advised to have an enteral feeding tube inserted prophylactically at day 1 post HCT. ANS was initiated in 228 (47%) patients who met pre-defined feeding criteria that include actual or anticipated oral intake below 1/3 of estimated requirement for 5 or more days or significant weight loss or low body mass index. Total of 245 (51%) patients had adequate enteral nutrition (EN) either orally (N=198) or with use of ETF (N=47). Patients in whom ETF could not be established received PN (N=148, 31%) in order to provide adequate nutrition. The remaining 91 (19%) patients had inadequate nutrition due to either curtailed ANS (N=33) or a failure to start ANS because of a lack of feeding access via any route (N=58).The effects of patient, disease and transplant factors were studied in univariate analyses on NRM, acute GvHD and engraftment, following which multivariate analyses showed significant associations of NRM with age > 50 years (hazard ratio (HR) 2.3; 95% confidence interval (CI) 1.4 - 3.7; P=0.001); previous autograft (HR 2.4; 95% CI 1.3 - 4.5; P=0.007) and positive recipient CMV serology (HR 1.9; 95% CI 1.1 - 3.2; P=0.019). In addition, HRs were significantly increased in the PN and inadequate nutrition groups compared to those with adequate enteral intake: adequate PN: HR 3.2; 95% CI 1.7 - 6.0, inadequate nutrition: HR 4.4; 95% CI 2.4 - 8.0; all P<0.001 (Figure). There were increased incidences of gastrointestinal GvHD of any stage and acute GvHD > grade 1 in patients who received PN (HR 2.0; 95% CI 1.2 - 3.3; P=0.006, and HR 1.8; 95% CI 1.1 - 3.0; P=0.018, respectively), but not in those with inadequate nutrition compared to adequate EN. Other significant covariates in the model for both increased overall and gut GvHD were the use of myeloablative versus reduced intensity conditioning P=0.001 and P<0.001 and female donor to male recipient versus other combinations P=0.047 and P=0.025 respectively.In conclusion the data show that adequate nutrition during allogeneic HCT is associated with improved non-relapsed mortality at 100 days. Adequate EN is associated with significantly better results for this outcome than adequate PN. Furthermore adequate EN, predominantly via oral intake may be associated with lower incidence of overall and gut GvHD when compared to PN, perhaps because of its ability to maintain gut mucosal integrity and for support of the gastrointestinal tract environment, including gut microflora. Although the retrospective nature of this study can only indicate association, the significant hazard ratios reported warrant further research into optimising enteral nutrition in recipients of HCT. [Display omitted] DisclosuresMilojkovic:Novartis: Honoraria; Bristol Myers Squibb: Honoraria; Pfizer: Honoraria; Ariad: Honoraria. Apperley:Incyte: Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; Bristol Myers Squibb: Honoraria, Speakers Bureau; Ariad: Honoraria, Speakers Bureau.

Caphosol for prevention of oral mucositis in pediatric myeloablative haematopoietic cell transplantation

Background:The primary objective was to determine whether topically administered Caphosol, rinsed orally four times daily at the initiation of conditioning, reduces the duration of severe oral mucositis (OM) compared with placebo among children and adolescents undergoing haematopoietic cell transplantation (HCT).Methods:This was a Children’s Oncology Group multicentre randomised double-blinded placebo-controlled clinical trial. Patients between the ages of 4 and 21 years who were scheduled to undergo myeloablative HCT for any indication were randomised to Caphosol or placebo saline rinses four times daily from initiation of conditioning through day +20. Subjects were assessed daily for OM using the World Health Organisation (WHO) Oral Toxicity Scale, Mouth Pain Categorical Scale (0–10) and the Oral Mucositis Daily Questionnaire (OMDQ). The primary end point was duration of severe OM (WHO ⩾3).Results:The study enrolled 220 participants with a median age of 13.7 years (range 4.0–21.9); 163 (74%) received allogeneic HCT. The mean (±s.d.) duration of severe OM was not reduced among Caphosol (4.5±5.0 days) vs placebo (4.5±4.8; P=0.99) recipients. The incidence of severe OM in the Caphosol and placebo arms was 63% (57 out of 91) and 68% (62 out of 91), respectively (P=0.44). There were no significant differences in any of the secondary end points between the groups.Conclusions:Caphosol did not reduce severe OM when compared with placebo among children and adolescents undergoing myeloablative HCT. Studies to identify effective interventions for OM are needed in this population.

Cord-Blood Transplantation in Patients with Minimal Residual Disease

BackgroundThe majority of patients in need of a hematopoietic-cell transplant do not have a matched related donor. Data are needed to inform the choice among various alternative donor-cell sources.MethodsIn this retrospective analysis, we compared outcomes in 582 consecutive patients with acute leukemia or the myelodysplastic syndrome who received a first myeloablative hematopoietic-cell transplant from an unrelated cord-blood donor (140 patients), an HLA-matched unrelated donor (344), or an HLA-mismatched unrelated donor (98).ResultsThe relative risks of death and relapse between the cord-blood group and the two other unrelated-donor groups appeared to vary according to the presence of minimal residual disease status before transplantation. Among patients with minimal residual disease, the risk of death was higher in the HLA-mismatched group than in the cord-blood group (hazard ratio, 2.92; 95% confidence interval [CI], 1.52 to 5.63; P=0.001); the risk was also higher in the HLA-matched group than in the cord-blood group but not significantly so (hazard ratio, 1.69; 95% CI, 0.94 to 3.02; P=0.08). Among patients without minimal residual disease, the hazard ratios were lower (hazard ratio in the HLA-mismatched group, 1.36; 95% CI, 0.76 to 2.46; P=0.30; hazard ratio in the HLA-matched group, 0.78; 95% CI, 0.48 to 1.28; P=0.33). The risk of relapse among patients with minimal residual disease was significantly higher in the two unrelated-donor groups than in the cord-blood group (hazard ratio in the HLA-mismatched group, 3.01; 95% CI, 1.22 to 7.38; P=0.02; hazard ratio in the HLA-matched group, 2.92; 95% CI, 1.34 to 6.35; P=0.007). Among patients without minimal residual disease, the magnitude of these associations was lower (hazard ratio in the HLA-mismatched group, 1.28; 95% CI, 0.51 to 3.25; P=0.60; hazard ratio in the HLA-matched group, 1.30; 95% CI, 0.65 to 2.58; P=0.46).ConclusionsOur data suggest that among patients with pretransplantation minimal residual disease, the probability of overall survival after receipt of a transplant from a cord-blood donor was at least as favorable as that after receipt of a transplant from an HLA-matched unrelated donor and was significantly higher than the probability after receipt of a transplant from an HLA-mismatched unrelated donor. Furthermore, the probability of relapse was lower in the cord-blood group than in either of the other groups.

Donor-Recipient Matching for KIR Genotypes Reduces Chronic GVHD and Missing Inhibitory KIR Ligands Protect against Relapse after Myeloablative, HLA Matched Hematopoietic Cell Transplantation

BackgroundAllogeneic hematopoietic cell transplantation (HCT) can be curative for many hematologic diseases. However, complications such as graft-versus-host disease (GVHD) and relapse of primary malignancy remain significant and are the leading causes of morbidity and mortality. Effects of killer Ig-like receptors (KIR)-influenced NK cells on HCT outcomes have been extensively pursued over the last decade. However, the relevance of the reported algorithms on HLA matched myeloablative HCT with rabbit antithymocyte globulin (ATG) is used for GVHD prophylaxis remains elusive. Here we examined the role of KIR and KIR-ligands of donor-recipient pairs in modifying the outcomes of ATG conditioned HLA matched sibling and unrelated donor HCTMethods and FindingsThe study cohort consisted of 281 HLA matched sibling and unrelated donor-recipient pairs of first allogeneic marrow or blood stem cell transplantation allocated into ‘discovery’ (135 pairs) and ‘validation’ (146 pairs) cohorts. High resolution HLA typing was obtained from the medical charts and KIR gene repertoires were obtained by a Luminex® based SSO method. All surviving patients were followed-up for a minimum of two years. KIR and HLA class I distributions of HCT pairs were stratified as per applicable definitions and were tested for their association with cause specific outcomes [acute GVHD grade II-IV (aGVHD), chronic GVHD needing systemic therapy (cGVHD) and relapse] using a multivariate competing risks regression model as well as with survival outcomes [relapse-free survival (RFS), cGVHD & relapse free survival (cGRFS) and overall survival (OS)] by multivariate Cox proportional hazards regression model. A significant association between KIR genotype mismatching (KIR-B/x donor into KIR-AA recipient or vice versa) and cGVHD was found in both discovery (p = 0.001; SHR = 2.78; 95%CI: 1.50–5.17) and validation cohorts (p = 0.005; SHR = 2.61; 95%CI: 1.33–5.11). High incidence of cGVHD associated with KIR genotype mismatching was applicable to both sibling and unrelated donors and was specific to recipients who had one or two C1 bearing HLA-C epitopes (HLA-C1/x, p = 0.001; SHR = 2.40; 95%CI: 1.42–4.06). When compared with KIR genotype mismatched transplants, HLA-C1/x patients receiving grafts from KIR genotype matched donors had a significantly improved cGRFS (p = 0.013; HR = 1.62; 95%CI: 1.11–2.39). Although there was no effect of KIR genotype matching on survival outcomes, a significantly reduced incidence of relapse (p = 0.001; SHR = 0.22; 95%CI: 0.10–0.54) and improved relapse-free survival (p = 0.038; HR = 0.40; 95%CI: 0.17–0.95) was observed with one or more missing ligands for donor inhibitory KIR among the recipients of unrelated donor transplants.ConclusionsThe present study for the first time presents the beneficial effects of KIR genotype matching in reducing cGVHD in myeloablative transplant setting using HLA matched (sibling and unrelated) donors. The findings offer a clinically applicable donor selection strategy that can help control cGVHD without affecting the risk of relapse and/or identify patients at a high risk of developing cGVHD as potential candidates for preemptive therapy. The findings also affirm the beneficial effect of one or more missing inhibitory KIR ligands in the recipient in reducing relapse and improving a relapse free survival in unrelated donor transplants.

Human leukocyte antigen supertype matching after myeloablative hematopoietic cell transplantation with 7/8 matched unrelated donor allografts: a report from the Center for International Blood and Marrow Transplant Research.

The diversity of the human leukocyte antigen (HLA) class I and II alleles can be simplified by consolidating them into fewer supertypes based on functional or predicted structural similarities in epitope-binding grooves of HLA molecules. We studied the impact of matched and mismatched HLA-A (265 versus 429), -B (230 versus 92), -C (365 versus 349), and -DRB1 (153 versus 51) supertypes on clinical outcomes of 1934 patients with acute leukemias or myelodysplasia/myeloproliferative disorders. All patients were reported to the Center for International Blood and Marrow Transplant Research following single-allele mismatched unrelated donor myeloablative conditioning hematopoietic cell transplantation. Single mismatched alleles were categorized into six HLA-A (A01, A01A03, A01A24, A02, A03, A24), six HLA-B (B07, B08, B27, B44, B58, B62), two HLA-C (C1, C2), and five HLA-DRB1 (DR1, DR3, DR4, DR5, DR9) supertypes. Supertype B mismatch was associated with increased risk of grade II-IV acute graft-versus-host disease (hazard ratio =1.78, P=0.0025) compared to supertype B match. Supertype B07-B44 mismatch was associated with a higher incidence of both grade II-IV (hazard ratio=3.11, P=0.002) and III-IV (hazard ratio=3.15, P=0.01) acute graft-versus-host disease. No significant associations were detected between supertype-matched versus -mismatched groups at other HLA loci. These data suggest that avoiding HLA-B supertype mismatches can mitigate the risk of grade II-IV acute graft-versus-host disease in 7/8-mismatched unrelated donor hematopoietic cell transplantation when multiple HLA-B supertype-matched donors are available. Future studies are needed to define the mechanisms by which supertype mismatching affects outcomes after alternative donor hematopoietic cell transplantation.

Impact of Donor and Recipient Cytomegalovirus Serostatus on Outcomes of Antithymocyte Globulin–Conditioned Hematopoietic Cell Transplantation

Although previous studies involving allogeneic hematopoietic cell transplantation (HCT) without in vivo T cell depletion by rabbit antithymocyte globulin (ATG) have reported a substantial survival difference between D−R− and D+R− patients, but little to no survival difference between D−R+ and D+R+ patients (D, donor; R, recipient; +, cytomegalovirus [CMV] seropositive; −, CMV seronegative), whether this applies to HCT using ATG is unknown. We studied 928 patients who underwent myeloablative HCT for hematologic malignancies in Alberta between 1999 and 2014 who received graft-versus-host disease (GVHD) prophylaxis using ATG (Thymoglobulin, 4.5 mg/kg) in addition to methotrexate and cyclosporine. D−R− and D+R− patients had similar survival (no significant difference). D−R+ patients had a substantially lower survival than D+R+ patients (41% versus 59% at 5 years; P = .001). This difference was attributed to higher nonrelapse mortality, apparently due to higher GVHD-associated mortality. Survival rates were also lower for D−R+ HLA-matched sibling transplant recipients compared with D+R+ HLA-matched unrelated donor transplant recipients (44% versus 66% at 5 years; P = .009). In conclusion, when using ATG, choosing a seronegative donor for a seronegative patient is relatively unimportant, whereas choosing a seropositive donor for a seropositive patient is important, even if this requires the use of a seropositive matched unrelated donor graft.