Total Body Irradiation Conditioning Research Articles

Conventional CD4+CD25- and Regulatory CDCD4+25+ t Cells Have Opposite Effects on Progenitor Cells and Hematopoietic Reconstitution Following Stem Cell Transplantation

The bone marrow (BM) is a complex microsystem to support lifelong blood production. At steady-state most hematopoietic stem cells (HSC) are quiescent. However, in situations of increased demand, their activation is triggered by an array of signals, such as cytokines. Following hematopoietic cell transplantation (HCT) in the phase of hematopoietic reconstitution maximal blood production is needed. In an HCT donor HSC are given together with immune cells in the belief that T cells support HSC engraftment and regeneration of the blood system. Yet, states of immune mediated BM insufficiency, hypoplasia, and cytopenias are often observed. Moreover, with increased use of reduced intensity conditioning (RIC) engraftment failure has reemerged as a serious problem.Here, we studied the effects of distinct T cell subsets on hematopoietic reconstitution following HCT; specifically, we examined how conventional CD4+CD25- T cells (CD4conv) vs regulatory T cells (CD4+CD25+, Treg) modify the BM environment and influence donor-HSC activity and engraftment. We used minor-mismatched mouse models, non-myeloablative total body irradiation (TBI) conditioning and transplantations of purified HSC (KTLS; cKit+Thy1.1loLin–Sca-1+) plus selected T cell subsets. Recipients of HSC, HSC+Treg or HSC+CD8+ - but not HSC+CD4conv- demonstrated prompt donor engraftment with mixed chimerism in all lineages. Transplantation of HSC+Treg resulted in significantly faster lymphocyte recovery and higher levels of donor chimerism compared with recipients of HSC, HSC+CD8+ or HSC+CD4conv. Particularly B-cell regeneration was markedly higher in HSC+Treg-recipients compared with all other groups. In contrast, (B-) lymphopoiesis was severely impaired in recipients of HSC+CD4conv; when lymphocytes recovered eventually they were of host type. Moreover, in BM and spleens of HSC+CD4conv recipients pronounced hypocellularity was observed. This suppression of hematopoiesis was due to IFNg secretion of donor CD4conv cells, which were activated by dendritic cells via IL-12. High cytokine levels (of both IL-12 and IFNg) were only detectable in the BM (and not the spleen) of HSC+CD4conv recipients, where they resulted in an arrest of early hematopoiesis at the stage of short-term HSC and decreased cell-cycle activity within the progenitor compartment. As a consequence more mature multipotent progenitors were lacking. The key role of IFNg in halting hematopoietic maturation was confirmed by using CD4conv cells from IFNg-/- mice, which had no suppressive effects on BM cellularity and maturation of blood cells; rather, recipients of HSC+IFNg-/-CD4conv cells had equivalent cell numbers and subset distributions as mice given HSC alone. We hypothesized that differences of hematopoietic regeneration and donor engraftment relate to cell cycle activity of HSC in presence of CD4conv vs Tregs. To study the influence of these CD4-subsets on HSC cycling in more detail FACS-purified Treg vs CD4conv cells were infused into congenic mice following low-dose TBI-stimulation. In fact, on d+8 post-infusion HSC in the BM of Treg-recipients had increased cell-cycling activity in long-term-HSC and multipotent-progenitor fractions compared with mice given CD4conv cells or radiation only. These data lead us to speculate that Tregs promote, directly or indirectly, HSC proliferation; in the context of an allogeneic HCT this increased cycling of host HSC my open-up the niche space required to allow donor HSC to engraft. In contrast, CD4convinhibited HSC cycling activity, resulting in BM hypoplasia and cytopenias; at the same time donor HSC engraftment was impaired due to HSC-niche occupation by quiescent host HSC.Our findings underscore the critical role of T cells in regulating hematopoiesis under physiologic conditions and even more following allogeneic HCT. While donor T cells are generally believed to improve regeneration of the blood post-HCT and to be required to overcome host barriers, our data suggest Treg facilitate engraftment and hematopoiesis by increasing HSC cycling-activity and thereby making marrow sites available. CD4conv appear to have the opposite effect, resulting in decreased HSC proliferation and maturation - thus occupation of HSC niches. Our studies are of particular relevance to allogeneic HCT settings using RIC, where host HSC persist and grafts can be rejected by residual host immune cells. DisclosuresNo relevant conflicts of interest to declare.

Nonmyeloablative Allogeneic Hematopoietic Stem Cell Transplant for the Treatment of Patients with Hematologic Malignancies Using Busulfan, Fludarabine, and Total Body Irradiation Conditioning Is Effective in an Elderly and Infirm Population

The BuFluTBI conditioning regimen was designed with the primary goal of reducing non-relapse mortality (NRM) while maximizing primary disease control in patients ineligible for myeloablative conditioning. Patients with hematologic malignancies for whom limited long-term survival was expected with standard therapy were administered an outpatient conditioning regimen of busulfan 3.2 mg/kg IV on day −5, fludarabine 30 mg/m2 IV on days −4, −3, −2, and 200 cGy of total body irradiation (TBI) followed by stem cell infusion from related or unrelated donors. GVHD prophylaxis included cyclosporine and mycophenolate mofetil. 147 patients were enrolled from 2005-2011; 59% with myeloid disease and 41% with lymphoid disease. The median age was 64, and the median comorbidity index (HCT-CI) score was 3. Overall survival (OS), with 3.2 years median follow-up, was 60% at 1 year and 48% at 2 years, with projected OS 37% at 5 years. Relapse rates were 29% at 1 year and 33% at 2 years, with relapse mortality of 13% at 1 year, and 20% at 2 years. Nonrelapse mortality (NRM) at 1 year was 27% and 33% at 2 years. 54% of patients developed grade II-IV aGVHD and 67% of patients developed cGVHD within 2 years. On multivariate analysis, HCT-CI score 4 or greater, pre-transplant KPS less than 90, delayed platelet engraftment of more than 15 days, and grade II-IV aGVHD were found to be independent predictors of poor survival. There was no difference in OS or PFS between lymphoid and myeloid malignancies. BuFluTBI is an efficacious NMA regimen, active in both myeloid and lymphoid disease, and is ideally suited for use in patients age 65 and older or with an HCT-CI of 4 or greater.

Incidence and risk factors for cataract after haematopoietic stem cell transplantation for childhood leukaemia: an LEA study.

Cataract was prospectively assessed by serial slip lamp tests in 271 patients included in the Leucémie Enfants Adolescents (LEA) programme, the French cohort of childhood leukaemia survivors. All had received haematopoietic stem cell transplantation (HSCT) after total body irradiation (TBI, n = 201) or busulfan-based (n = 70) myeloablative conditioning regimen. TBI was fractionated in all but six patients. The mean duration of follow-up from HSCT was 10·3 years. Cataract was observed in 113/271 patients (41·7%); 9/113 (8·1%) needed surgery. Cumulative incidence after TBI increased over time from 30% at 5 years to 70·8% and 78% at 15 and 20 years, respectively, without any plateau thereafter. The 15-year cumulative incidence was 12·5% in the Busulfan group. A higher cumulative steroid dose appeared to be a cofactor of TBI for cataract risk, in both univariate and multivariate Cox analysis. In the multivariate analysis, cataract had an impact in two quality of life domains: 'the role limitation due to physical problems' and 'the role limitation due to emotional problems'. These data suggest that with increasing follow-up, nearly all patients who receive TBI, even when fractionated, will suffer from cataract that can impact on their quality of life and that high cumulative steroid dose is a cofactor.

The EBMT/EMCL consensus project on the role of autologous and allogeneic stem cell transplantation in mantle cell lymphoma.

The role of both autologous (autoSCT) and allogeneic stem cell transplantation (alloSCT) in the management of mantle cell lymphoma (MCL) remains to be clarified. We conducted a consensus project using the RAND-modified Delphi consensus procedure to provide guidance on how SCT should be used in MCL. With regard to autoSCT, there was consensus in support of: autoSCT is the standard first-line consolidation therapy; induction therapy should include high-dose cytarabine and Rituximab; complete or partial remission should be achieved before autoSCT; Rituximab maintenance following autoSCT is not indicated; and omission of autoSCT in 'low-risk' patients is not indicated. No consensus could be reached regarding: autoSCT in the treatment of relapsed disease following non-transplant therapy; the value of positron emission tomography scanning and minimal residual disease (MRD) monitoring; in vivo purging with Rituximab; total body irradiation conditioning for autoSCT; and preemptive Rituximab after autoSCT. For alloSCT, consensus was reached in support of: alloSCT should be considered for patients relapsing after autoSCT; reduced intensity conditioning regimens should be used; allogeneic immunotherapy should be used for MRD eradication after alloSCT; and there is a lack of prognostic criteria to guide the use of alloSCT as first-line consolidation. No consensus was reached regarding the role of alloSCT for relapsed disease following non-transplant therapy.

Induction of Mixed Chimerism Depletes Pre-existing and De Novo–Developed Autoreactive B Cells in Autoimmune NOD Mice

Destruction of pancreatic islet β-cells in type 1 diabetes (T1D) is mainly mediated by autoimmune T and B lymphocytes. We reported that induction of major histocompatibility complex (MHC)-mismatched mixed chimerism reversed autoimmunity and reestablished thymic negative selection of autoreactive T cells in NOD mice, but it is still unclear how mixed chimerism tolerizes autoreactive B cells. The current studies were designed to reveal the mechanisms on how mixed chimerism tolerizes autoreactive B cells in T1D. Accordingly, mixed chimerism was induced in NOD mice through radiation-free nonmyeloablative anti-CD3/CD8 conditioning and infusion of donor CD4(+) T cell-depleted spleen and whole bone marrow (BM) cells or through myeloablative total body irradiation conditioning and reconstitution with T cell-depleted BM cells from donor and host. Kinetic analysis of percentage and yield of preplasma and plasma B cells, newly developed B-cell subsets, and their apoptosis was performed 30-60 days after transplantation. Induction of MHC-mismatched mixed chimerism results in depleting host-type pre-existing preplasma and plasma B cells as well as augmenting apoptosis of immature transitional T1 B cells, including insulin-specific B cells in a donor B cell-dependent manner. Therefore, induction of MHC-mismatched mixed chimerism depletes pre-existing and de novo-developed autoreactive B cells.

Does Total Body Irradiation Conditioning Improve Outcomes of Myeloablative Human Leukocyte Antigen–Identical Sibling Transplantations for Chronic Lymphocytic Leukemia?

An allogeneic hematopoietic cell transplantation from an HLA-identical donor after high-dose (myeloablative) pretransplantation conditioning is an effective therapy for some people with chronic lymphocytic leukemia (CLL). Because CLL is a highly radiosensitive cancer, we hypothesized that total body irradiation (TBI) conditioning regimens may be associated with better outcomes than those without TBI. To answer this, we analyzed data from 180 subjects with CLL receiving myeloablative doses of TBI (n = 126) or not (n = 54), who received transplants from an HLA-identical sibling donor between 1995 and 2007 and reported to the Center for International Blood & Marrow Transplant Research. At 5 years, treatment-related mortality was 48% (95% confidence interval [CI], 39% to 57%) versus 50% (95% CI, 36% to 64%); P = NS. Relapse rates were 17% (95% CI, 11% to 25%) versus 22% (95% CI, 11% to 35%); P = NS. Five-year progression-free survival and overall survival were 34% (95% CI, 26% to 43%) versus 28% (95% CI, 15% to 42%); P = NS and 42% (95% CI, 33% to 51%) versus 33% (95% CI, 19% to 48%); P = NS, respectively. The single most common cause of death in both cohorts was recurrent/progressive CLL. No variable tested in the multivariate analysis was found to significantly affect these outcomes, including having failed fludarabine. Within the limitations of this study, we found no difference in HLA-identical sibling transplantation outcomes between myeloablative TBI and chemotherapy pretransplantation conditioning in persons with CLL.

Role Of High-Dose Cytarabine and Total Body Irradiation Conditioning before Autologous Stem Cell Transplantation In Mantle Cell Lymphoma - A Comparison Of Nordic MCL2, HOVON 45, and European MCL Younger Trials

IntroductionHigh-dose cytarabine containing immuno-chemotherapy followed by autologous stem cell transplantation (ASCT) has been established as standard first-line treatment in younger mantle cell lymphoma (MCL) patients (ESMO guideline, Ann Oncol 2013). However, the role of total body irradiation (TBI) as conditioning regimen for ASCT has not been clarified so far. A retrospective EBMT survey of 418 MCL patients suggested a benefit of TBI with respect to the rate of relapse in patients who achieved a partial remission before ASCT (Rubio et al., ASH 2010). We combined the individual patient data of the Nordic MCL2 trial (Geisler et al., Blood 2008), the HOVON 45 trial (van't Veer et al., BJH 2008, both without TBI), and the high-dose cytarabine containing study arm of the European MCL Younger trial (Hermine et al., ASH 2012, with TBI) to evaluate potential differences in long term outcome. MethodsAll trials included patients with advanced stage MCL up to 66 years and a central review of histology. Induction treatment of Nordic MCL2 consisted of 6 alternating courses of Maxi-CHOP or high-dose cytarabine (12g/m2 per cycle, 8g/m2 in patients > 60 years, total cumulative dose 24-36g/m2) combined with 4-6 cycles rituximab, in HOVON 45 three courses R-CHOP were followed by one cycle of high-dose cytarabine (16g/m2), and in MCL Younger patients received 6 alternating courses of R-CHOP or R-DHAP (4g/m2 cytarabine per cycle, total cumulative dose 12g/m2). Conditioning before ASCT consisted of BEAM or BEAC in Nordic MCL2, and BEAM in HOVON 45, whereas a TBI-containing regimen (TAM: 10 Gray TBI, 6g/m2 cytarabine, 140mg/m2 melphalan) was applied in MCL Younger. We compared baseline characteristics, progression free survival (PFS) overall survival (OS) after ASCT from the three patient cohorts with adjustment for MIPI (Hoster et al., Blood 2008) and quality of remission before ASCT. ResultsIn Nordic MCL2, HOVON 45, and MCL Younger 145, 61, and 171 patients were transplanted in complete (CR) or partial (PR) remission (median age 57, 55, and 56 years, p=0.24). According to MIPI, 46%, 56%, and 67% were low risk, whereas 22%, 13%, and 11% were high risk patients (p=0.006). Five-year PFS after ASCT was 61%, 50%, and 78%, respectively (p<0.001) after a median observation time of 6.6, 6.5, and 4.2 years). After adjustment for MIPI score and quality of response (CR/unconfirmed CR vs. PR) before ASCT, the hazard ratio for PFS after ASCT of MCL Younger vs. Nordic MCL2 was 0.75 (p=0.17). Among the patients with CR or unconfirmed CR before ASCT, the adjusted hazard ratio was 0.91 (p=0.76) in comparison to 0.66 (p=0.17) among the PR patients. On the other hand, the hazard ratio of MCL Younger in comparison to HOVON 45 was 0.45 (p=0.001) after adjustment for MIPI score. OS after ASCT was not different between the three cohorts with 5-year OS rates of 75%, 71%, and 80%, respectively (p=0.61). ConclusionThe longer PFS after ASCT of MCL Younger compared to HOVON 45 patients may be due to the different time schedule of cytarabine during induction or to a higher efficacy of TBI vs. BEAM, as the total chemotherapy doses were comparable and we adjusted for MIPI. We could not see an improved PFS after ASCT of MCL Younger compared to Nordic MCL2 patients transplanted in CR or unconfirmed CR and, after adjustment for the different risk profiles, this was also not clearly seen for patients transplanted in PR. Taking into account the substantially higher cytarabine dose in Nordic MCL2 during induction one might speculate that this fact at least partially compensated for a higher efficacy of TBI. Multivariable analyses incorporating additional prognostic factors (Ki-67 and MRD) will help to clarify the impact of the individual parts of the current multimodal approach in younger MCL patients.On behalf of the European Mantle Cell Lymphoma Network Disclosures:No relevant conflicts of interest to declare.

Peripheral Blood Stem Cells Versus Bone Marrow Grafts For HLA-Matched Unrelated Donor Transplantation In Adult Patients With Acute Myeloid Leukemia; The Role Of Low-Dose Rabbit Anti-Thymocyte Globuline In The Prophylaxis Of Graft-Versus-Host Disease

BackgroundIn the setting of unrelated donor stem cell transplantation (URD-SCT), several data showed that peripheral blood stem cells (PBSC) resulted in faster engraftment but increased the risk of acute or chronic graft-versus-host disease (GVHD), while other transplant outcomes were comparable. However, there are some limitations in these data due to heterogeneous diseases or registry data characterized by various other treatment strategies. Notably, we have added low-dose rabbit anti-thymocyte globuline (ATG) only to the patients who received URD-SCT with PBSC because of their higher risk of developing GVHD. In this setting, we compared the long-term outcomes of URD-SCT using PBSC and bone marrow (BM) and studied the role of low-dose rabbit ATG in the prophylaxis of GVHD. MethodsBetween March 2004 and April 2012, 115 adult patients with AML underwent myeloablative (n=87) or reduced-intensity (n=28) conditioning HLA-matched URD-SCT with PBSC (n=70) or BM (n=45) grafts. All patients received tacrolimus and short-course methotrexate for GVHD prophylaxis. Low-dose rabbit ATG (Thymoglobuline®, 1.25 mg/kg for 2 days) was added only to the patients who received URD-SCT with PBSC grafts. The median follow-up of survivors was 44 months (range, 2-100) for PBSC transplants and 54 months (range, 8-105) for BM transplants (P=0.01). ResultsBaseline characteristics were not significantly different between the two groups except for total-body irradiation conditioning regimen (72.9% vs. 91.1%; P=0.02). PBSC transplants showed faster recovery of neutrophil (11 days vs. 13 days; P=0.03) and platelet (12 days vs. 18 days; P=0.01) counts than BM transplants. No difference was observed in the cumulative incidence of acute GVHD (grade ≥2) at 100 days (54.3% vs. 64.4%; P=0.38) and chronic GVHD at 4 years (61.4% vs. 60.0%; P=0.88) between the two groups. In spite of adding low-dose rabbit ATG, PBSC transplants did not show higher incidence of relapse compared to that of BM transplants (30.8% vs. 31.2%; P=0.53). Other transplant outcomes including non-relapse mortality (13.5% vs. 6.9%; P=0.24), disease-free survival (55.7% vs. 61.9%; P=0.80), and overall survival (63.3% vs. 63.2%; P=0.59) were comparable between the two groups. In multivariate analysis, graft source had no impact on transplantation outcomes. Regardless of graft source, transplants in ≥CR2 had higher relapse risk (hazard ratio, 2.45; 95 % CI, 1.04-5.76; P=0.04), poorer disease-free survival (hazard ratio, 2.68, 95% CI, 1.29-5.56; P=0.01) and overall survival (hazard ratio, 2.59; 95% CI, 1.20-5.59; P=0.02). ConclusionAdding low-dose rabbit ATG to the patients who received URD-SCT with PBSC may lower the incidence of acute and chronic GVHD comparably to that of URD-SCT with BM without increasing the incidence of relapse. Disclosures:No relevant conflicts of interest to declare.

Phase II Trial Of Medium-Dose VP-16, Cyclophosphamide and Total-Body Irradiation Conditioning Regimen Before Allogeneic Stem Cell Transplantation For Acute Lymphoblastic Leukemia In Adults

BackgroundThe prognosis of adult patients (pts) with acute lymphoblastic leukemia (ALL) is dismal, and allogeneic stem cell transplantation (allo-SCT) is performed in most pts. However, even for pts treated with allo-SCT using the standard regimen of cyclophosphamide with total body irradiation (CY/TBI), the prognosis is not satisfactory due to a high rate of relapse. We previously reported excellent outcomes in adult pts with ALL undergoing allo-SCT conditioned with medium-dose VP-16, CY and TBI (medium-dose VP/CY/TBI). We therefore conducted a prospective nationwide multicenter phase II trial (UMIN trial number 000001672) to evaluate the efficacy of this conditioning regimen. MethodsThe eligibility criteria of this study were as follows: (1) diagnosis of ALL or acute biphenotypic leukemia (ABL), (2) aged 15-49 years, (3) in CR, (4) first SCT, (5) PS (ECOG) 0-2, (6) intact organ function, and (7) HLA-serologically 6/6 matched donor. Pts with Burkitt leukemia were ineligible for this study. Conditioning regimen consisted of medium-dose VP (15 mg/kg once daily i.v. for two days) and CY (60 mg/kg once daily i.v. for two days) combined with fractionated TBI (total dose: 12 Gy). Stem cell source was limited to bone marrow (BM) or peripheral blood stem cell (PBSC). The primary endpoint of this study was event-free survival (EFS) at one year after SCT, and the events were defined as death or relapse. The expected 1-year EFS was estimated to be 75%, and the threshold 1-year EFS was estimated to be 55%, on the basis of our previous observations. ResultsBetween February 2009 and August 2011, 52 pts were enrolled, and 50 pts met the criteria. Among 50 eligible pts, the median age was 33.5 years (range, 17-49 years), and 15 pts (30%) were over 40. Twenty-three (46%) pts were female. Forty-eight (96%) pts had ALL and 2 (4%) had ABL. Nineteen (38%) pts were Philadelphia chromosome (Ph)-positive. Forty-seven (94%) pts were in first CR at SCT, and 3 (6%) in second CR. Among pts with ALL in first CR (n=45), 38 (84%) had high-risk disease. Twenty-six (52%) pts underwent SCT from a related donor and 24 (48%) from an unrelated donor. Forty (80%) pts received BM and 10 (20%) received PBSC. All pts achieved neutrophil engraftment. The incidence of grade II-IV and III-IV acute graft-versus-host disease (GVHD) was 38% and 8%, respectively, and that of chronic GVHD was 54%. After 1-year follow-up of the final enrollment (range, 379-1218 days), the 1-year EFS was 76% (95% confidence interval (CI): 62-86%, Figure). One-year overall survival was 80% (95% CI: 66-89%). No pts died within 100 days after SCT and 1-year non-relapse mortality (NRM) was 14% (95% CI: 6-25%). No secondary malignancies were observed during the-follow-up period. The 100-day and 1-year relapse rate was 2% (95% CI: 0-9%) and 10% (95% CI: 4-20%), respectively. The 1-year EFS for pts with high-risk and standard-risk disease was 76% (95% CI: 59-87%) and 71% (95% CI: 26-92%), Ph-positive and negative pts was 79% (95% CI: 53-92%) and 76% (95% CI: 56-88%), and pts over 40 years and under 40 years was 73% (95% CI: 44-89%) and 77% (95% CI: 59-88%), respectively. In univariate analysis, high-risk disease, Ph-positivity and higher age were not significant risk factors for EFS. ConclusionsThe results demonstrate that the conditioning regimen of medium dose VP/CY/TBI for allo-HCT in adult pts with ALL enable good disease control without increase in NRM, even for relatively high age pts and pts with high-risk disease. A phase III trial comparing this regimen with standard CY/TBI regimen for adult pts with ALL is warranted. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Single center experience with total body irradiation and melphalan (TBI-MEL) myeloablative conditioning regimen for allogeneic stem cell transplantation (SCT) in patients with refractory hematologic malignancies

We retrospectively evaluated the tolerability and efficacy of fractionated total body irradiation (TBI) (1,200 cGy) and melphalan (MEL) (100–110 mg/m2) myeloablative conditioning in 48 patients with nonremission AML (n = 14), ALL (n = 10), NHL (n = 18), and other refractory hematologic malignancies (n = 6) who received allogeneic stem cell transplantation (SCT) between 2002 and 2011. Median age was 48 years (22 to 68); 14 out of 26 leukemia patients (54 %) had circulating blasts at transplant, 20 (50 %) evaluable patients had poor-risk cytogenetics, 12 (25 %) had prior SCT, and 10 (21 %) received stem cells from a mismatch donor. All patients received tacrolimus with or without methotrexate for GVHD prophylaxis. At the time of analysis, 13 patients (27 %) were alive and disease free. Engraftment was complete in all patients. The median time to ANC recovery (>500) was 12 days (range, 6–28). The most common grade III and IV toxicities were mucositis and infections. Eighteen patients (43 %) developed grade II–IV acute GVHD, and eight (26 %) had extensive chronic GVHD. Of 44 evaluable patients for response, 28 (64 %) achieved a complete remission (CR), and seven (15 %) had a partial remission after the transplant. With a median follow-up of 30 months (4 to 124 months) for surviving patients, the cumulative incidence of relapse was 45 % at 1 year, and the probability of overall survival (OS) at 5 years was 22.5 %. Multivariate analysis showed that platelet count (<80,000/mL) and lactic dehydrogenase (>500 IU/L) at SCT were associated with relapse. Age less than 53 years and CR after SCT were associated with better OS. Our data suggest that TBI-MEL can result in CR in two thirds, durable remission in one third, and 5-year survival in about one quarter of patients with nonremission hematologic malignancies. Further studies with TBI-MEL in standard risk transplant patients are warranted.

Academic Difficulties and Occupational Outcomes of Adult Survivors of Childhood Leukemia Who Have Undergone Allogeneic Hematopoietic Stem Cell Transplantation and Fractionated Total Body Irradiation Conditioning

We studied academic and employment outcomes in 59 subjects who underwent allogeneic hematopoietic stem cell transplantation (a-HSCT) with fractionated total body irradiation (fTBI) for childhood leukemia, comparing them with, first, the general French population and, second, findings in 19 who underwent a-HSCT with chemotherapy conditioning.We observed an average academic delay of 0.98 years among the 59 subjects by Year 10 of secondary school (French class Troisième), which was higher than the 0.34-year delay in the normal population (P < .001) but not significantly higher than the delay of 0.68 years in our cohort of 19 subjects who underwent a-HSCT with chemotherapy. The delay was dependent on age at leukemia diagnosis, but not at fTBI. This delay increased to 1.32 years by the final year of secondary school (Year 13, Terminale) for our 59 subjects versus 0.51 years in the normal population (P = .0002), but did not differ significantly from the 1.08-year delay observed in our cohort of 19 subjects.The number of students who received their secondary school diploma (Baccalaureate) was similar to the expected rate in the general French population for girls (observed/expected = 1.02) but significantly decreased for boys (O/E = 0.48; CI: 95%[0.3–0.7]). Compared with 13.8% of the general population, 15.3% of the cancer survivors received no diploma (P = NS).Reported job distribution did not differ significantly between our cohort of childhood cancer survivors and the general population except that more female survivors were employed in intermediate-level professional positions.Academic difficulties after fTBI are common and their early identification will facilitate educational and professional achievement.

The hematopoietic cell transplantation specific comorbidity index and survival after extracorporeal photopheresis, pentostatin, and reduced dose total body irradiation conditioning prior to allogeneic stem cell transplantation

Hematopoietic-cell-transplantation-specific-comorbidity-index (HCT-CI) has been reported as a predictor of survival in allogeneic-transplant recipients; however its validity has recently been challenged. We evaluated the association of HCT-CI with survival of transplant recipients who underwent reduced-intensity-conditioning (RIC) with photopheresis, pentostatin, and total-body-irradiation. Median age of 103 patients selected was 55 years. Most patients (58.3%) had high (≥ 3) HCT-CI. Median OS was 298 days. Age, disease-type, disease-status, HCT-CI correlated with survival on bivariate analysis. On multivariate analysis, only HCT-CI was significantly associated with OS (low HCT-CI HR=0.29, CI 0.091-0.886; intermediate HCT-CI HR=0.41, CI 0.226-0.752). Our findings suggest HCT-CI as an independent predictor of survival in the setting of RIC transplants.

Allogeneic Hematopoietic Cell Transplantation in First Remission Abrogates Poor Outcomes Associated with High-Risk Pediatric Acute Myeloid Leukemia

Despite remission rates of approximately 85% for children diagnosed with acute myeloid leukemia (AML), greater than 40% will die from relapsed disease. Patients with poor-risk molecular/cytogenetics and/or inadequate response to up-front therapy are typically considered high-risk (HR) and historically have poor outcomes with chemotherapy alone. We investigated whether allogeneic hematopoietic cell transplantation (allo-HCT) with best available donor in first remission (CR1) would abrogate the poor outcomes associated with HR AML in children and young adults treated with chemotherapy. We reviewed the outcomes of 50 consecutive children and young adults (ages 0 to 30 years) with AML who received a myeloablative allo-HCT between 2001 and 2010. Thirty-six patients (72%) were HR, defined as having FLT3-ITD mutations, 11q23 MLL rearrangements, chromosome 5 or 7 abnormalities, induction failure, and/or having persistent disease. The majority of patients received cyclophosphamide and total body irradiation conditioning, and graft-versus-host-disease (GVHD) prophylaxis was cyclosporine based. Transplantation outcomes for HR patients were compared to standard-risk patients, with no significant differences observed in overall survival (72% versus 78%, P = .72), leukemia-free survival (69% versus 79%, P = .62), relapse (11% versus 7%, P = .71), or treatment-related mortality (17% versus 14%, P = .89). Children and young adults with HR-AML have comparable outcomes to standard-risk patients following allo-HCT in CR1.

Treatment of primary CNS lymphoma (PCNSL) following successful treatment of systemic non-Hodgkin’s lymphoma (NHL): a case series

Management of PCNSL occurring after successful treatment of systemic non-Hodgkin's lymphoma (NHL) is poorly defined. Illustrate a treatment approach for PCNSL following prior treatment of a systemic NHL. A retrospective case series of 6 patients (mean age 60 years; range 46-65) diagnosed with a diffuse large B cell lymphoma of the CNS following prior successful treatment of a systemic NHL (low-grade in 2; high-grade in 4). Mean interval to diagnosis of PCNSL after diagnosis of systemic NHL was 12 months (range 7-18). In 4/6 patients in whom genetic analysis could be performed, the PCNSL and NHL differed. Treatment utilized high-dose methotrexate and rituximab (immunochemotherapy) followed in patients with a radiographic complete response by autologous peripheral stem cell transplant (ASCT) with total body irradiation (TBI) and multi-agent conditioning chemotherapy (BEAM: carmustine, etoposide, cytarabine, melphalan). 5/6 patients had a radiographic complete response to immunochemotherapy and were treated with ASCT. 4/5 patients were free of disease following ASCT with a mean follow-up of 3 years (range 0.5-4 years). There were no toxic deaths and all patients transplanted successfully engrafted within 28 days (mean 18). Using a treatment paradigm similar to that utilized for recurrent systemic NHL (induction chemotherapy followed by ASCT) for PCNSL occurring metachronously after successful treatment of systemic NHL appears safe and effective.

A Critical Role of MyD88 Signaling in Donor T Cells for Graft-Versus-Host Disease (GVHD) and Graft-Versus-Leukemia Effect (GVL) After Experimental Allogeneic Hematopoietic Stem Cell Transplantation (allo-HSCT)

AbstractAbstract 1893The therapeutic potential of allogeneic hematopoietic stem cell transplantation (allo-HSCT) relies on the graft-versus-leukemia effect (GVL) to eradicate residual tumor cells by immunologic mechanisms. However, graft-versus-host disease (GVHD) remains the major toxicity of allo-HSCT. Alloreactive donor T cells are important effector cells in the development of GVHD, and proinflammatory cytokines enhance the generation of donor antihost cytotoxic function. Myeloid differentiation factor (MyD88) is a cytoplasmic adaptor molecule essential for integrating and transducing the signals generated by the Toll-like receptor (TLR) family. TLR engagement on professional antigen-presenting cells induces their maturation, resulting in optimal T-cell activation. However, recent advances indicate that the adjuvant effects of certain TLR agonists may also be attributed to the activation of TLRs and MyD88 directly in T cells. Both CD4 and CD8 T cells express functional TLRs. It remains to be defined whether direct TLR signaling on donor T cells is critical for GVHD or GVL activity.We used C57BL/6 (H-2b) → B6D2F1 (H-2b/d) experimental allo-HSCT model, which differs at major and minor histocompatibility loci, to address the role of donor T cell MyD88 signaling on GVHD and GVL. Lethally irradiated recipient mice were transplanted TCD-BM (5 × 106) together with either wild-type (WT) or MyD88 knock out (KO) mice spleen T cells (1 × 106) on day 0 and then host-type P815 mastocytoma or L1210 leukemia (H-2d) cells were injected either intravenously (3 × 103) or subcutaneously (1 × 106) on day 1 to generate a GVHD/GVL model. First of all, clinical GVHD scores were comparable between recipients of WT T cells and MyD88 KO T cells. At 70 days post-allo-HSCT, 50 % of allogeneic recipients of WT T cells died due to severe GVHD, but necropsy showed no evidence of tumor. In contrast, 83.5% of those of MyD88 KO T cells died with gross evidence of tumors (P<.05). Moreover, subcutaneous tumors in the allogeneic recipients receiving MyD88 KO T cells exhibited markedly increased growth in vivo compared to those receiving WT T cells (tumor volume on day 41, 15205.6 vs. 373.9 mm3, P<.01). GVHD mortality is critically dependent on donor CD4 T cells in this donor/recipient strain combination (B6 → B6D2F1) and CD8 T cells that mediate cytotoxicity are more potent effectors of GVL. The percentages of donor T cells to undergo proliferation or apoptosis in response to alloantigens in vivo between the two T cell types was examined; apoptosis of CD8 T cells in recipients of MyD88 KO T cells was significantly enhanced compared to those of WT T cell recipients (P<.01) whereas apoptosis of CD4 T cells was comparable between two groups. Resultingly, the percentages of CD8 T cells in recipients of MyD88 KO T cells were significantly lower (P<.01). We next examined the effects of MyD88 signaling in donor T cells on cytolytic activity to host antigens. Splenocytes harvested from WT mice showed stronger cytolytic activity against P815 targets compared to those from MyD88 KO mice (P<.01). After allogeneic mixed leukocyte reaction, responder T cells from MyD88 KO mice showed markedly reduced IFN-γ, MCP-1 and IL-17A production with a significant augmentation in IL-10 secretion. We further evaluated the effect of T-cell MyD88 deficiency on GVL mediated by the intensity of total body irradiation (TBI) conditioning (1300 vs. 900 cGy, Exp Hematol 2011; 39: 1018–29). Enhanced GVL in the allogeneic recipients receiving 1300 cGy TBI was not shown in the recipients of MyD88 KO T cells.In summary, these results highlight a critical role for MyD88 signaling in T-cell activation and cytotoxicity, offering the opportunity for improving GVL activity by targeting TLR-MyD88 signaling within donor T cells. Furthermore, these data demonstrated that MyD88 deficiency in T cells can impair cytolytic function or subsequent GVL activity of CD8 T cells without significant change in the severity of CD4-dependent GVHD. This difference is attributed to the fact that MyD88 deficiency in T cells causes an enhanced apoptosis of donor CD8 T cells but not donor CD4 T cells in vivo after HSCT. Disclosures:No relevant conflicts of interest to declare.

Favorable Outcomes of Autologous Stem Cell Transplantation in Adult Patients with Philadelphia Chromosome-Negative Acute Lymphoblastic Leukemia in First Remission: On Behalf of the Adult Acute Lymphoblastic Leukemia Working Group of the Japan Society for Hematopoietic Cell Transplantation (JSHCT)

AbstractAbstract 2021 Background:Postremission treatment for adult Philadelphia chromosome-negative acute lymphoblastic leukemia [Ph(-)ALL] in first remission remains elucidated and the role of autologous stem cell transplantation (auto-SCT) is still controversial in the application for Ph(-)ALL patients. We retrospectively analyzed the consolidative role of auto-SCT as a postremission therapy for adult Ph(-)ALL in first remission. Patients and Methods:Among 1962 adult Ph(-)ALL patients registered in the JSHCT database, we selected cases receiving auto-SCT with myeloablative preparative regimens in first complete remission from 1983 to 2009. Results:A total of 155 patients with 86 male patients were analyzed. The median age was 25 years (range: 16 to 74) and 79% of patients were less than 45 years of age at transplant. The number of patients having white blood cell (WBC) count <30000/ul and ≥30000/ul at diagnosis was 81 and 21, respectively. The number of patients showing B- and T-cell phenotypes was 80 and 21, respectively. Cytogenetic data were available in 96 patients, of which 69 patients had normal karyotypes. Most patients (84%) underwent auto-SCT before 2002, and 42 out of 155 patients received TBI combined conditioning regimens. With a median follow-up of 10 years, the 10-year overall survival rate of all 155 patients was 41% (95%CI: 33 to 49). Among patients younger than 45 years, the survival rate of adolescent and young adult (AYA) patients (aged 24 years or less) was comparable to that of patients aged 25 to 44 years (p= 0.110). Cumulative incidence of relapse and non-relapse mortality (NRM) at 10 year after auto-SCT was 47% (95%CI: 39 to 55) and 10% (95%CI: 6 to 16), respectively. In univariate analysis, factors associated with worse overall survival were age 45 years or more [Hazard ratio (HR): 1.67, p=0.038] and usage of conditioning regimens without total body irradiation (TBI) (HR: 1.51, p=0.110). Factors associated with decreasing relapse rates were usage of TBI conditioning regimens (HR: 0.35, p=0.069) and transplant year 2000 and later (HR: 0.35, p=0.141). In multivariate analysis, factors correlated with increasing the overall survival rate and decreasing the relapse rate were age less than 45 years [HR: 0.59 (95%CI: 0.36 to 0.96), p=0.034] and usage of TBI conditioning regimens [HR: 0.55 (95%CI: 0.31 to 0.99), p=0.048], respectively. There were no significant factors associated with NRM in univariate and multivariate analyses.We next performed comparison of auto-SCT with allogeneic stem cell transplantation (allo-SCT) in adult Ph(-)ALL patients. Patients undergoing allo-SCT were selected from the same JSHCT database. A total of 921 patients were identified as cases receiving allo-SCT with myeloablative preparative regimens in first complete remission. With a median follow-up of 4.95 years, the 4-year overall survival rate was 63% (95%CI: 51 to 59). Allo-SCT yielded better overall survival rate than that of auto-SCT (63% vs. 48% at 4 year, p=0.0004). In subset analyses, we limited analyses to the groups of patients younger than 45 years and receiving TBI regimens followed by auto-SCT (n=31) or allo-SCT (n=685). There were no differences in baseline patients’ characteristics between the two groups except age [auto-SCT: 20 years (range: 16 to 40) vs. allo-SCT: 28 years (range: 16 to 44), p<0.001]. The 4-year overall survival rates in patients undergoing auto-SCT and allo-SCT were 71% (95%CI: 52 to 84) and 66% (95% CI: 62 to 70), respectively (p=0.510, Figure. 1). No statistically significant factors were found in the analyses of relapse and NRM. Conclusions:Our analyses demonstrated that auto-SCT produced excellent results showing a plateau in long-term survival and that clinical outcome of auto-SCT was comparable to that of allo-SCT in some part of patients. Candidates who obtained most benefit from auto-SCT was those younger than 45 years and well tolerated with TBI combined myeloablative conditioning regimens. Since optimal timing of postremission therapy is critical for adult Ph(-)ALL patients, auto-SCT in first complete remission could be one of promising treatment strategies for the patients. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Bleeding Phenotype of Murine Bernard Soulier Syndrome Is Potentially Corrected by Non-Myeloablative Hematopoietic Stem Cell Transplantation

Abstract 3340Bernard Soulier Syndrome (BSS) is an inherited bleeding disorder caused by a defect in the platelet glycoprotein (GP)Ib/IX complex. Platelet transfusion is the primary treatment for hemorrhage but is often limited because of the potential for provoking allo-immunization and refractoriness. We have previously shown that the macrothrombocytopenia and prolonged bleeding of murine BSS (GPIbαnull) can be corrected by myeloablative total body irradiation (TBI) and transplantation of hematopoietic stem cells (HSCs) transduced with a lentivirus that expresses hGPIbα under integrin αIIb promoter control (2bIbαLV). For application of this gene therapy approach to the treatment of human patients, it is important to minimize treatment-related adverse effects. In this study, we established a transgenic mouse that expresses hGPIbα at levels similar to the average levels observed in 2bIbαLV transduced HSC recipients that can be used as a consistent source of bone marrow HSCs (hGPIbαtg+). We undertook two approaches for evaluation of HSC transplantation using hGPIbαtg+ mouse bone marrow (BM) cells; 1) determine the percentage of hGPIbαtg+ HSCs necessary for therapeutic benefit and 2) determine if non-myeloablative strategies can achieve hGPIbα expression levels sufficient to correct the bleeding phenotype of GPIbαnullmice.In order to determine the percentage of HSCs required to achieve therapeutic effects, mixed BM chimeras were generated by reconstituting lethally irradiated GPIbαnull mice with variable mixtures (5% - 100%) of BM cells isolated from hGPIbαtg+ and GPIbαnull mice. Tail bleeding time assays performed after BM reconstitution demonstrated that 10% hGPIbαtg+ BM mononuclear cells mixed with 90% GPIbαnull BM mononuclear cells were sufficient to correct the tail bleeding time (n=5). Platelet analysis showed that the bleeding phenotype was rescued in recipients having higher than 40 × 103/μl of hGPIbαtg+ platelets, which corresponds to 6.5% of wild type mouse platelet counts (630 ± 57 × 103/μl, n = 8). These results suggest therapeutic potential for non-myeloablative conditioning regimens for the treatment of murine BSS.Thus we next tested the transplantation of hGPIbαtg+ mouse BM cells into GPIbαnull recipients conditioned with two non-myeloablative doses of busulfan (25 mg/kg on days -2 and -1). Analysis of platelets by flow cytometry showed that, as expected, the percentage of hGPIbα-positive platelets in busulfan-conditioned recipients was lower than those transplanted after lethal TBI conditioning (63.2% ±36.6%, n = 15 vs. 95.2% ±1.7%, n = 8). However, tail bleeding time assays showed that bleeding times of busulfan-conditioned recipients were corrected and not significantly different from lethally irradiated recipients (2.7 ± 3.1 minutes, n = 15 vs 1.9 ± 1.5 minutes, n = 8), while no untreated GPIbαnull mice (n=8) stopped bleeding within 10 minutes. Platelet counts were also significantly increased in busulfan-conditioned recipients compared to untreated GPIbαnull mice (381 ± 132 × 103/μl, n = 11 vs. 181 ± 35 × 103/μl, n = 11). Thus non-myeloablative doses of busulfan conditioning and transplantation of hGPIbαtg+mouse BM cells were shown to achieve relevant levels of engraftment in murine BSS with significantly corrected bleeding times and platelet counts.Antibody response to hGPIbα and immune-mediated thrombocytopenia was documented in 3 of 15 recipient mice, suggesting immunogenicity of hGPIbα transgene protein in GPIbαnullmice partially immunosuppressed with busulfan. However, immunotolerance was identified without treatment and antibody disappeared in all three mice 3 to 7 months after BM transplantation.In conclusion, non-myeloablative doses of busulfan conditioning may be a reasonable alternative to TBI for the BMT-based treatment of BSS and could be utilized in non-myeloablative autologous gene therapy in human BSS. Disclosures:No relevant conflicts of interest to declare.

ACE Polymorphism and Idiopathic Pneumonia Syndrome After Allogeneic Stem Cell Transplantation

AbstractAbstract 1943 BackgroundIdiopathic pneumonia syndrome (IPS) was defined as a subset of these patients who have sings and symptoms of pneumonia, and evidence for widespread alveolar injury in the absence of lower respiratory tract infection. Risk factors for IPS include previous infections, a pre-transplant condition, a low performance status prior to transplantation, a high dose of total-body irradiation (TBI), and the presence of graft-versus-host disease (GVHD). Although IPS is a significant clinical complication after allogeneic HSCT, progress in understanding its pathogenesis has been limited. Formerly we retrospectively analyzed the incidence of non-infectious pulmonary dysfunction (NIPD) and the ACE genetic polymorphism in 118 Japanese patients who underwent HSCT from HLA identical sibling donors(1). The previously result is that patients who have D/D genotype are associated with high frequency of NIPD. Here, we show the validation study to prove the relationship of ACE polymorphism and IPS, referencing to recently American Thoracic Society criteria(2), in an independent cohort. Material and MethodsWe analyzed 149 patients who consecutively received HSCT in Tokai University Hospital from 2006 to 2011. Patients background disease were AML; n = 61, ALL; n = 30, NHL; n = 27, MDS; n = 14, AA; n = 8, CML; n = 6, Primary Myelofibrosis; n = 2 and Multiple Myeloma; n = 1. The conventional regimen for myeloid malignancy is CY and TBI (12 Gy divided with 6 fractions); n = 66 or TAI; n = 5 or BU and CY; n = 8, for lymphoid malignancy is CY+TBI 12Gy with VP-16; n = 10. RIST regimen is Fludarabin and Melphalan; n = 60. Inclusion criteria of using RIST were more than 55 year-old or low performance status or high grade of HCT-CI score. The ACE geno-type was determined by PCR amplification of intron 16, based on a previously described method.IPS was diagnosed according to previously published criteria, such as evidence of widespread alveolar injury by multilobar infiltrate, manifest on chest X-ray or computed tomography, as well as clinical symptoms of pneumonia, hypoxemia, and evidence of abnormal respiratory physiology, including restrictive impairment in a pulmonary function test.Host factors of interest included patient age, sex and underlying diagnosis. Transplantation characteristics included level of TBI conditioning, conditioning regimen, hematopoietic stem cell source (bone marrow, peripheral blood or cord blood), donor type (human leukocyte antigen [HLA]-matched or not and related donor or unrelated donor), female to male transplantation, kind of calcineurin inhibitor and acute GVHD. Death without signs of IPS was considered a competing risk in the analysis of IPS incidence. Acute GVHD was diagnosed and graded according to standard criteria. Only grades II and higher of aGVHD were considered for the analysis of aGVHD incidence. ResultsThere were 31 patients who had D/D genotype of ACE polymorphism in this cohort, and 12/31 (38.7%) D/D patients diagnosed as IPS, whereas I/D patients 3/64 (4.7%) and I/I patients 3/54 (5.6%), respectively. The D/D genotype was significantly more frequent in IPS patients than in non-IPS patients (RR; 8.38, P<0.0001, 95%CI 3.08–22.82). In multivariate analysis with competing-risk regression model, the D/D genotype is the most significant factor of developing IPS. ConclusionIn this single institute retrospective cohort study revealed the association between ACE insertion/ deletion polymorphism and developing IPS. These findings may confirm the association renin-angiotensin system and IPS after HSCT. Disclosures:No relevant conflicts of interest to declare.

Late relapses following reduced intensity allogeneic transplantation in patients with multiple myeloma: a long‐term follow‐up study

We analysed the long-term outcomes of 60 multiple myeloma patients who underwent reduced intensity allogeneic stem cell transplantation between August 2000 and March 2008. Regimens included fludarabine and melphalan conditioning (flu-mel regimen) for allogeneic haematopoietic cell transplant (HCT) or a planned tandem regimen consisting of high-dose melphalan conditioning for autograft followed by low-dose total body irradiation conditioning for allogeneic HCT (auto-allo regimen). Donors included human-leucocyte-antigen-matched siblings (n = 55) or matched unrelated donors (n = 5). With a median follow-up of 9·8 years, 7-year overall survival (OS) and progression-free survival (PFS) were 60% and 31%, respectively. By multivariate Cox regression analysis, disease status of complete response (CR) or partial response (PR) at transplant and the presence of chronic graft-versus-host disease were significantly associated with improved OS. Only disease status was significantly associated with improved PFS. We noted a surprising number of very late relapses, with six patients (10%) relapsing between 6 and 12 years post-transplant. Among the six late relapse patients, all were transplanted within 14 months of diagnosis, five had normal karyotypes, and five were in CR/PR. Our data provide additional evidence that, while survival may be extended by reduced intensity allogeneic transplant, ultimately, it may not offer a cure.

1084P - Autologous Stem Cell Transplantation (HCT) with or Without Total Body Irradiation (TBI) in Newly Diagnosed Mantle Cell Lymphoma (MCL) Patients

ABSTRACT Introduction MCL is considered incurable due to relapsing course and eventual resistance despite initial responses to treatment. The 1st line treatment in advanced disease is immunochemotherapy induction followed by high-dose chemotherapy +/- TBI and HCT in the first complete (CR) or partial remission (PR). The best conditioning regimen is unknown and the TBI role is one of the main issues. Very few retrospective analyses are available. Methods We retrospectively evaluated all MCL patients treated 1st line +/- TBI as a part of myeloablative procedure at the Oncology Institute in Warsaw between 1999-2011 with some patients treated in the European MCL Network trial for younger. We analyzed data for 7 women and 26 men, median age 56 years (39-63). Most (82%) had disease stage III-IV with bone marrow involvement in 64%. Majority received chemotherapy with rituximab for induction (79%). All received doxorubicin and 45% cytarabine. 22 had TBI conditioning (TBI group). Most of the remaining 11 patients received BEAM (non-TBI group). Before conditioning 18 had CR (12 before TBI, 6 before conditioning without TBI) and 15 PR (10 before TBI, 5 before conditioning without TBI). There were no statistically significant differences between groups, including age, sex, disease stage and MIPI. After HCT 27 patients had CR (18 in TBI, 9 in non-TBI), 6 remained in PR (4 in TBI, 2 in non-TBI). Median observation time from the start of therapy was 50.9 months (6.9-144.8) and from HCT 49.5 months (0.85-139.7). Results After HCT the 1, 3 and 5-year overall survival (OS) rates were 96.9%, 89.8%, 75% and the progression free survival (PFS) 93.7%, 73.1% and 67.9% respectively. In bivariate analysis the 1, 3 and 5-year OS rates were similar in TBI vs. non-TBI groups: 95.4% vs. 100%; 90.4% vs. 88.8%; 82.2% vs. 66.7% (p= 0.41). Comparison of 1, 3 and 5-year PFS rates between TBI vs. non-TBI groups: 95.2% vs. 90.9% and 86.6% vs. 47.1% and 78 % vs. 47.1% (p= 0.046) indicated superiority of TBI. In a multivariate analysis TBI was an independent PFS prognostic factor with relative risk 0.24 (95% CI 0.06–1.02) (p = 0.04). Conclusion The results showed PFS advantage of TBI conditioning prior to HCT in newly diagnosed MCL patients and no OS advantage. Disclosure All authors have declared no conflicts of interest.