HLA-identical Family Donor Research Articles

Moderate Incidence but Striking Correlation with TBI of Secondary Malignancies after HSCT in Children with ALL: Long-Term Follow-up from the Prospective International BFM- and Forum-Trials

Introduction: Total body irradiation (TBI)-based conditioning was found to be associated with superior leukemia-free survival when compared to chemo-based conditioning for children with ALL undergoing allogeneic hematopoietic stem cell transplantation (HSCT) in the prospective, international, randomized FORUM trial (Peters et al, JCO 2021). Nevertheless, TBI is considered as the major risk factor for developing secondary malignancies (SM). We and others have previously reported the incidence, risk factors, and outcomes of SM after HSCT in children with ALL (Eichinger et al, Leukemia 2022), but prospective studies of SM after HSCT in children are limited. Therefore, we analyzed the results of 2151 patients enrolled in the prospective BFM 2003 and the FORUM trial from 2003-2022. Patients and methods: We included data from all 668 patients (pts) treated in the BFM 2003 trial and from all 1483 patients treated in the FORUM trial with HSCT from HLA-identical family donors (MFD, 26% of patients), matched unrelated donors (MUD, 65%), and either related or unrelated mismatched donors (MMD, 9%). In the BFM 2003 trial pts >2 years (y) of age years were offered TBI/VP-16 (12 Gy TBI in 6 fractions of 2 Gy each, given as 2 fractions per day for 3 days; VP-16 60 mg/kg, maximum total dose 3600 mg) as conditioning. Only pts with contraindications for TBI received chemo-conditioning, which consisted of i.v. busulfan, cyclophosphamide and etoposide. In the FORUM trial pts >4y of age were randomized to receive either TBI- or chemo-based conditioning regimens; pts <4y were allocated to the chemo-conditioning arm consisting of fludarabine/thiotepa and either busulfan or treosulfan. Details on the transplant procedure have been previously described (C. Peters, et al. JCO 2015 /2021). Results: Centres from 31 countries on 5 continents contributed to the two studies. The median age was 9.2 (range 0.5-23) y. The majority were male (63%, 1356/2151) and >2 y of age at HSCT (94%, n=2024). TBI-based conditioning was applied in 64% (n=1429), while 34% (n=722) of pts received chemo-conditioning. TBI/VP16 was given in 27% (43/159) of age group 2-4y, and in 76% (1269/1672) of age group >4y. With a median follow-up of 3.29 (range 0.1-16.4) y, a total of 46 SM (33 in BFM 2003, 13 in FORUM) were diagnosed at a median of 5.12 (range 0.4-13.4) y post HSCT, all but one in the TBI group. Four pts experienced ALL relapse prior to the occurrence of the SM leaving 42/2151 cases for further analysis. The 5-, 8-, and 10-y cumulative incidence (CI) of SM, with relapse and non-relapse mortality being competing events, were 0.02 (±0.01), 0.06 (±0.01), and 0.13 (±0.03), respectively. Details of the SM are described in Table 1. Regarding age at HSCT, no SM was observed in the very young age group (<2 years) (0/127), 4 SM in the 2-4 years group (2.2%, 4/181), 20 SM in the 4-10 years group (2.3%, 20/867), and 22 SM in the >10 years group (2.25%, 22/976) (p=n.s.). Six patients developed an additional SM: these were MDS (n=2), and glioblastoma, breast cancer, basal cell carcinoma, and squamous cell carcinoma (one each). The first SM occurred at a median of 5.12 (range 0.4-13.4) y, and the additional SM at 10.7 (range 4.3-12.1) y after HSCT. The probability of OS after SM diagnosis was 0.65 (±0.008) at 5y and 0.32 (±0.17) at 10y. Causes of death were SM in 12/14 cases and 2/14 ALL relapse-associated. All 3 glioblastoma-pts died within 8 months after diagnosis. 17/18 pts (94%) with thyroid cancer were alive at last follow-up (0-10 y after SM diagnosis). As shown in Figure 1, the 8-y CI of SM differed significantly between TBI- and chemo-conditioning (0.08[±0.02] versus 0.04[±0.04], p=0.004) in both age groups (2-4 y and >4 y). No significant correlation was observed with patient characteristics such as age, gender and ALL remission status. In addition, we did not identify other statistically significant transplant-specific risk factors including donor type, stem cell source, grade II-IV and III-IV aGVHD and cGVHD. Conclusions Updated data from two prospective studies using uniform regimens confirmed TBI-based conditioning as a risk factor for SM in pediatric ALL. Further analysis is ongoing regarding the association with immune phenotype of ALL and details of genetic risk factors (e.g. TP53 mutations). Rigorous long-term FU of TBI patients is mandatory.

PB1812: CORE BINDING FACTOR ACUTE MYELOID LEUKEMIA IN PEDIATRIC POPULATION: THE RESULTS OF A MONOCENTRIC EXPERIENCE

Background: The core binding factor acute myeloid leukemia (CBF-AML) is characterized by t(8;21) and inv(16)(p13q22)/t(16;16)(p13;q22) cytogenetic abnormalities. It is associated with a good prognosis. Aims: In this study, we aimed to assess the treatment outcome of the pediatric CBF- AML in comparison with non CBF-AML treated in our center. Methods: We retrospectively reviewed data of patients under the age of 20 diagnosed with de novo AML in our center during january 2005 and december 2020. The treatment protocol includes: a course of induction (Cytarabine 200mg/m2/day associated with Daunorubicine (DNR) 60 mg/m2/day or Novantrone 12mg/m2/day). If a complete remission (CR) is achieved the chemotherapy is followed by: a cure of ADE (Cytarabin, DNR, Etoposide) associated with 2 cures of high dose of Cytarabine (12g/m2) before 2011 and a cure of ADE associated with 3 cures of high dose of cytarabine (18g/m2) after January 2011. Allogeneic stem cell transplantation (ASCT) from matched sibling donors was limited to patients who are in CR1, having an HLA-identical family donor before January 2011 and for patients who are in CR2 after January 2011. Endpoints were complete remission (CR), overall survival(OS), event free survival (EFS) and relapse rate. Survival statistical analysis performed with Kaplan Meyer method. Results: A total of 52 patients were included, of whom 16 (30%) presented CBF genes. The median age was 10years. The median white blood cells count at diagnostic was 28G/L. Distribution according to the FAB classification was as followed: 1(6%)M1, 8(50%) M2, 6(38%) M4 and 1(6%) M6.the most frequent subgroup was M2 (vs M1 in non CMF-AML, p=0.001). Cytogenetic analysis showed the Inv 16 (p13;q22) in 3 cases (18%) and t(8;21) (q22;q22) were observed in 11 cases (68%). Two patients had both CBFB–MYH11and AML-ETO rearrangement. Six cases (38%) had additional cytogenetic abnormalities. The correlation between cases with and without additional cytogenetic abnormalities did not conclude to any significent difference in terms of CR rate, OS and EFS. We observed a comparatively higher CR rate (87% vs 51% p=0.018) and also a better OS rate (83% vs 35%, p=0.02) at 5 years between CBF-AML and non CBF-AML. In contrast, there was no statisticly significent difference in terms of the EFS (67%vs 62%, p=0.4) and the relapse rate (31% vs 43%, p=0.3) between the 2 groups. Relapse occurred in 5 cases (31%) at a median of 13 months. A second remission was obtained in 2/5 patients. ASCT was performed in only 4 cases (3 after RC1 and 1 after relapse). Summary/Conclusion: The frequency of core binding AML in our study is higher than what has been reported in the literature (30 vs 15%) with predominance of The cytogenetic t(8,21) (68%). The additional cytogenetic abnormalities has no prognostic value. Long term survival in our series compared favorably with results reported by cooperative groups. It can be concluded that ASCT in CR1 for pediatric CBF-AML is no longer indicated.

Long-Term Quality of Life after Hematopoietic Cell Transplantation for Sickle Cell Disease: A Preliminary Report from the Sickle Cell Transplant Evaluation of Long Term and Late Effects Registry (STELLAR)

▪Introduction: Sickle cell disease (SCD) is characterized by unpredictable, recurrent acute and chronic persistent pain, and progressive organ damage leading to substantial morbidity, impaired quality of life and increased healthcare utilization. Hematopoietic cell transplantation (HCT) is the only therapy for SCD with curative intent. HCT is associated with excellent overall and event free survival especially in young children undergoing HCT from HLA identical family donors. Given these outcomes and improved supportive care, HCT is increasingly being offered to adults with SCD. However, a paucity of data exists on health related quality of life (HrQoL) in patients who are long term survivors of HCT. Therefore, a clear need exists to study HrQoL in children and adults post HCT to determine the long term benefit of HCT for SCD. We report the results of an interim analysis of HrQoL in recipients of HCT for SCD.Methods: We enrolledchildren and adults with SCD ≥ 1-year post-HCT in the Sickle Cell Transplant Evaluation of Long Term and Late Effects Registry (STELLAR). We obtained patient self-report of health status and health practices using a web based platform. Individuals under age 18 years and/or proxies completed Patient Reported Outcome Measurement Information System (PROMIS) version 25. Individuals over age 18 completed PROMIS version 29. Surveys were completed at enrollment and annually thereafter. T-scores were calculated for each survey domain. HrQoL in children (PROMIS25) and adults (PROMIS29) was compared to age appropriate norms (mean 50 ± 10). Univariate analysis was performed by age, gender, marital status, time from transplant, history of preHCT stroke, frequency of pain, number of emergency department (ED) visits, length of stay, income, and education assessed at the time of PROMIS survey administration. Statistical analysis was conducted using SAS Version 9.4. Descriptive statistics for each variable were reported. For numeric covariates, the mean and standard deviation (SD) were calculated and presented with frequency and its percentage shown for category variables. For repeated measures, generalized estimating equation (GEE) model was performed to detect the association. The significance level was set at 0.05.Results: Twenty-seven individuals completed 30 PROMIS25 surveys and 15 individuals completed 19 PROMIS29 surveys from 2017-2021. The mean age at transplant was 11.4years (SD 3.1) and 23.8 years (SD 6.2) in adults, respectively. Sixty percent and 50%, respectively, were female. The mean time from transplant was 4.2 years (SD 3.9) and 9.1 years (SD 7.1), respectively. Physical function/mobility, anxiety, depression, fatigue, and pain T-scores for each PROMIS measure are reported below in Table 1. Univariate analysis of PROMIS25 T-scores showed a statistically significant difference in anxiety by age and peer relationships by age, gender, and time from transplant. Time from transplant also had a statistically significant association with pain interference. PROMIS29 T-scores also showed a statistically significant difference in anxiety by age. Gender had a statistically significant association with depression and fatigue. Number of ED visits had a significant association with physical function, depression, social participation, and pain interference (Table 2). Other covariates lacked a statistically significant association or had insufficient sample sizes for comparison.Conclusions: Long-term HrQoL after HCT for SCD is within population norms for adults and children, though children have better HRQoL compared to adults. Better scores in females suggests the need for study of gender as a mediator of HrQoL outcomes. The observed relationship between HrQoL domains and education, income, time from transplant, and number of ED visits, a surrogate for healthcare utilization, suggest the need for careful study of these and other factors that can influence HrQoL post HCT over the long-term. In addition, further research in patient reported outcomes has the potential to identify needed areas of intervention and surveillance for this population. [Display omitted] DisclosuresGuilcher: Project Sickle Cure Study: Other: Principal Investigator, Research Funding; BlueBirdBio: Research Funding.

Matched Family Donor Lymphocyte Infusions as First Cellular Therapy for Patients with Severe Primary T Cell Deficiencies

Patients with primary immunodeficiencies caused by severe defects in T cell immunity are at risk of acquiring life-threatening infections. Cellular therapies are necessary to establish normal T cell function and to allow for long-term survival. This is most commonly achieved by hematopoietic stem cell transplantation (HSCT), but the outcome of this procedure is impaired if active infections are present at the time of HSCT. Donor lymphocyte infusions (DLIs) are a well-established therapeutic strategy following HSCT to treat viral infections, improve donor cell engraftment, or achieve graft-versus-leukemia activity in malignant disease. Here we present a cohort of 6 patients with primary T cell deficiencies who received transfusions of unselected mature donor lymphocytes prior and not directly related to allogeneic HSCT. DLIs obtained from the peripheral blood of HLA-identical (10/10) family donors were transfused without prior conditioning to treat or prevent life-threatening infections. All patients are alive with a follow-up of 0.5 to 16.5 years after the initial T cell administration. Additional cellular therapies were administered in 5 of 6 patients at 0.8 to 15 months after the first DLI. Mild cutaneous graft-versus-host disease (GVHD, stage ≤2) was observed in 3 of 6 patients and resolved spontaneously. We provide evidence that unselected HLA-identical DLIs can effectively prevent or contribute to overcome infections with a limited risk for GVHD in T cell deficient patients. The T cell system established by this readily available source can provide T cell function for years and can serve as a bridge to additional cellular therapies or, in specific conditions, as definite treatment.

Matched versus Haploidentical Hematopoietic Stem Cell Transplantation as Treatment Options for Primary Immunodeficiencies in Children

Primary immunodeficiencies (PIDs) are inherited disorders of the immune system with allogeneic hematopoietic stem cell transplantation (HSCT) as the only curative treatment in some of them. In case an HLA-matched donor is not available, HSCT from a haploidentical family donor may be considered. We compared the outcomes of HSCT from HLA-matched unrelated or related donors (MUDs or MRDs) and mismatched related haploidentical donors (MMRDs) in patients with a variety of PIDs in 2 centers. A total of 44 pediatric patients were evaluated. We reviewed the outcomes of 25 children who underwent transplantation with HLA-matched grafts (MRD, n=13; MUD, n=12) and 19 patients receiving haploidentical stem cells. Bone marrow (BM) was transplanted in 85% (MRD) and 75% (MUD) of the matched cohort and peripheral blood stem cells (PBSCs) in 15% (MRD), 25% (MUD), and 100% (MMRD). All but 9 patients (MRD, n=6; MMRD, n=3) with severe combined immunodeficiency (SCID) received a chemotherapy-based conditioning regimen. Immune reconstitution of T, B, and natural killer cells was comparable for all groups with an advantage of recipients of MRD grafts in early CD4 reconstitution. However, deaths due to viral infections occurred more often in the haploidentical cohort. The disease-free survival was 91.7% (MRD), 66.7% (MUD), and 62.7% (MMRD), respectively. Grade II to IV acute graft-versus-host disease (GVHD) occurred in 15% (MRD), 8% (MUD), and 21% (MMRD) of the patients. Only 1 patient had severe grade IV GVHD in the MRD group, whereas no grade >II GVHD was observed in the MUD or MMRD cohort. These data indicate that in the absence of a suitable HLA-identical family donor, haploidentical HSCT may be a viable option for patients with life-threatening disease and urgent need of HSCT.

P1832IGG4 RELATED DISEASE: NEPHROPATHY AND BONE MARROW FAILURE IN A 2 YEAR-OLD CHILD

Abstract Background and Aims IgG4 related disease (IgG4 RD) is a recently recognized systemic immune-mediated disorder. Pathophysiology of the disease is still unclear. It is characterized by fibro-inflammatory damage of the tissues, IgG-4 positive plasma-cells and often by elevated serum IgG4. This systemic disease can potentially affect every organ. Renal involvement can include tubulo-interstitial nephritis (TIN), membranous glomerulopathy (MGP) and retroperitoneal fibrosis. The epidemiology is still poorly described, but the disease seems more frequent in men over 50 years of age. Only few cases of IgG4 RD are reported in pediatric patients. Method We describe the first case of IgG4 related kidney disease (IgG4 RKD) in a child with concomitant bone marrow failure. Results M.C., a 2 year-old child, was diagnosed in 2017 with a trilinear bone marrow failure (HB 7.2 g/dL; PLT 6.000/mmc; PMC 923/mmc). Bone marrow biopsy showed poor and dyshomogeneous cellularity (20%) and lymphoplasmacytic infiltrate organized in two follicular structures. All investigations performed to rule out inherited bone marrow failure were negative (DEB test, telomere lenght measurement, c-Mpl mutation analysis, mithocondrial DNA analysis) IgG subclass analysis showed elevated serum levels of IgG4 subclass (353 mg/dL- normal level < 120 mg/dL). During the hospitalization, kidney failure with tubular acidosis was also found (creatinine 1.3 mg/dL, eGFR 28.5 mL/min/1.73 mq, bicarbonate 8.3 mEq/L). Urine analysis showed microematuria, proteinuria (1.07 g/L) and granular casts. Renal ultrasound did not demonstrate abnormal findings. A renal biopsy was performed and a kidney sample with up to 40 glomeruli was obtained. Light microscopy (H&E, JSM, PAS and Masson’s trichrome stains) showed tubule-interstitial inflammatory infiltrate (mainly composed of lymphoplasmacytic cells), irregular thickening of the glomerular basement membranes. IHC stains for C4D showed subepithelial deposits (++). IF was negative for IgA, IgM, C4 and C1q while showed subepithelial glomerular membrane IgG deposits (+++) with granular pattern and tubular wall deposits; glomerular deposits (+) and focal tubular deposits (+++) of C3. A diagnosis of MGP associated with TIN was made. IHC staining for IgG4 was also performed, which demonstrated plasmacells with overlapping positivity for IgG and IgG4. After the diagnosis of IgG4 RKD, an immune-suppressive therapy with steroids (1 mg/kg/die)– targeting both the haematological disorder and glomerulopathy - was started, without clinical response. Thereafter the patient underwent bone marrow transplant from HLA-identical family donor. Conclusion GMP indeed is a very uncommon disease in childhood. Moreover, the association of GMP with TIN is reported in few cases in the literature. Only in the last decade some case of TIN and GMP have been recognized as IgG4 RD and few cases have been reported in adults of IgG4 RKD with simultaneous TIN and GMP. To exclude primary GMP we will perform also the research of antiPLA2r1 antibodies in kidney biopsy. However, the specificity of antiPLA2r in children is lower than in adults and the association of primary GMP with IgG4 TIN is unlikely. IgG4 RD is an emerging systemic disease and it should be taken into account in differential diagnosis in systemic auto-immune diseases, also in the pediatric age. IgG4 RKD and bone marrow failure IgG4 RD are very rare in children but its real incidence among pediatric patients could be still underestimated.

Selecting ß-Thalassemia Patients for Gene Therapy: A Decision-Making Algorithm

Introduction and Aim Till today, the only curative and most widely used therapy for β-thalassemia (β-TDT) is allogeneic HSCT: the European Society for Bone Marrow Transplantation Hemoglobinopathy Registry reported over 90% overall survival in under-14 patients transplanted from an HLA identical family donor. However, with the new therapeutic scenario opened up by Gene Therapy (GT), it has become essential to identify and prioritize patient profiles for which GT could be applied. The "Pesaro Patients Risk Classification" showed the importance of risk stratification in order to achieve the best results. The Italian Scientific Society for Thalassemias and Hemoglobinopathies (SITE) closely involved in the cure and overall approach to these pathologies, decided to carry out this project of analysis and assessment to establish the possible inclusion and exclusion criteria for access to GT of patients with β-TDT and to collect the outcomes. The aim of this study is to identify which patients with β-TDT could benefit from GT, based on evidence and consensus. Methods The decision-making algorithm was developed within the scientific activity of SITE, which defined the feasibility of the project and selected the multidisciplinary panel of experts in hemoglobinopaties for the elaboration of clinical issues. Published literature (Medline, PubMed, Embase, Cochrane Library) was searched in order to get solid evidences regarding best candidates to allogeneic SCT, who should not therefore undergo GT. Evaluation of literature and scientific evidences were reported and discussed through call conferences and mails communications. The final review has been performed by a pool of external reviewers who evaluated the clinical relevance, the applicability, the legibility of the document and the consistency between the recommendations and the summaries of the tests produced to test the algorithm. This step is in progress. The final version of the document will be made available on the web site of SITE (www.site-italia.org). The outcomes of the procedures will be collected in the electronic clinic database used by the Centers (i.e Webthal©) to perform a risk stratification. Results and Conclusions The patient selection procedure must be performed by the joint evaluation of the Center of the "Hemoglobinopathies Italian Network" together with the qualified treatment Center for HCS transplantation. The document is proposed as a dynamic and up-datable tool. It is structured such as to allow two levels of consultation: an interactive flow chart (Figure) presenting the different clinical issues discussed with conclusive practical indications linked to chapters providing detailed information on each aspect of the subject. Applying the appropriate cautionary considerations, patients are considered non-eligible in the case of: exclusion criteria indicated by the Regulatory Authorities (i.e. EMA/CHMP/166977/2019);Severe iron overload and/or organ damage (i.e. pulmonary hypertension). Manageable iron overload is a condition of re-evaluation. Caution is mandatory in the evaluation of patients with complications or comorbidities. The access to GT needs to be re-evaluated on the basis of scientific and regulatory updates. Figure Disclosures Longo: Blue Bird Bio: Consultancy. Pinto:Novartis: Consultancy; Bluebird Bio.: Consultancy. Angelucci:Novatis: Honoraria, Other: Chair Steering Committee TELESTO protocol; Celgene: Honoraria, Other: Participation in DMC; BlueBirdBio: Other: Local advisory board; Jazz Pharmaceuticals: Other: Local advisory board; Roche: Other: Local advisory board; Vertex Pharmaceuticals Incorp., and CRISPR Therapeutics: Other: Participation in DMC. Cappellini:Novartis: Membership on an entity's Board of Directors or advisory committees; Vifor Pharmaceutical: Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Honoraria; CRISPR Therapeutics: Membership on an entity's Board of Directors or advisory committees; Genzyme/Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees. Piga:Acceleron Pharma: Research Funding; Novartis: Consultancy, Research Funding; Celgene Corporation: Consultancy, Research Funding. Forni:Roche, Erithropoiesis Stimulation: Research Funding; Celgene, Erithropoiesis Stimulation: Research Funding; Novartis, Iron chelation: Research Funding; BlueBirdBio: Consultancy.

Daratumumab as Maintenance After Peripheral Blood Stem Cell Transplantation From HLA-identical or Haploidentical Family Donor in the Treatment of Refractory or Relapsed Multiple Myeloma: a Phase 2 Trial

Daratumumab as Maintenance After Peripheral Blood Stem Cell Transplantation From HLA-identical or Haploidentical Family Donor in the Treatment of Refractory or Relapsed Multiple Myeloma: a Phase 2 Trial

Administration of BPX-501 Cells Following Αβ- T and B-Cell-Depleted HLA-Haploidentical HSCT in Children with Fanconi Anemia

Abstract Background Allogeneic hematopoietic stem cell transplantation (HSCT) has been shown to rescue trilineage cytopenias and to prevent occurrence of myeloid malignancies in patients with Fanconi Anemia (FA). HLA-identical family donor HSCT is a recommended treatment strategy with an ≥80% cure rate, and outcomes of HSCT from unrelated donors have progressively improved over time. However, HLA-partially matched (haplo) HSCTs have been historically associated with inferior results. Innovative approaches of graft manipulation, such as selective depletion of αβ-T and B cells, have recently been reported to improve the outcomes of haplo-HSCT in children with non-malignant disorders, however obstacles remain, such as delayed recovery of adaptive immunity with a risk of life-threatening infections. Novel strategies aimed at accelerating immune reconstitution are warranted to optimize the outcomes of patients transplanted from a HLA-haploidentical family donor. BPX-501 is an allogeneic product consisting of T cells modified to express the inducible caspase-9 (iC9) safety switch and truncated CD19 to allow monitoring and expansion of BPX-501 following transplant. The polyclonal nature of the BPX-501 provides broad virus and tumor-specific immunity, while the safety switch provides the unique ability to promptly and durably resolve graft-versus-host disease (GvHD) symptoms following the administration of rimiducid which induces dimerization and activation of iC9, inducing apoptosis of BPX-501. Aims To evaluate the safety and efficacy (acceleration of immune recovery and prevention of transplant-related mortality while maintaining low rates of acute and chronic GvHD) of BPX-501 administered after a αβ T and B-cell depleted haplo-HSCT in pediatric patients with FA. Methods This is a multicenter US (NCT03301168) and EU (NCT02065869), prospective trial utilizing αβ-T- and B-cell-depleted haplo-HSCT followed by infusion of donor lymphocytes genetically modified to express iC9 (BPX-501 T cells). BPX-501 cells were planned to be infused on day14±4 after the allograft per protocol. No post-transplant pharmacological GvHD prophylaxis was employed. Patients who develop GvHD resistant to conventional steroid therapy were eligible to receive ≥1 dose of dimerizing rimiducid activating iC9. The efficacy-evaluable population (EEP) was defined as any patient with FA who received HSCT, BPX-501 infusion and had at least one follow-up assessment. Results At the time of clinical cut-off (June 30th, 2018), 14 patients met the EEP definition. Nine and 5 patients were transplanted in the EU and US, respectively. The median follow-up was 23.5 mos (0.75 - 42 mos). Key baseline and transplant characteristics are detailed in Table 1. The median time for neutrophil and platelet engraftment was 14 (11-15) and 10 (8 - 11) days, respectively. One patient experienced primary graft failure (7.7% [95% CI: 0-22.2%]). Only one patient developed Grade I aGvHD (7.7% [95% CI: 0-22.2%]). Two patients developed cGvHD (19.2% [95% CI: 4-43.2%]), both cases being moderate. Rimiducid was not administered to any patient. One patient died after transplantation due to brain hemorrhage 25 days post HSCT. The event was unrelated to BPX-501 (TRM 7.1% [95% CI: 0-20.6%]). No patients died of infectious complications. The probability of both overall survival (OS) and disease-free survival (DFS) was 92.9% (95% CI: 79.4-100%). The median time from last red blood cell (RBC) transfusion was 23.6 mos (0.2 - 41.9 mos). CD3+ and CD3+CD4+ T cells above 500 cells/ml were achieved by 180 and 360 days, respectively. IgA and IgM levels achieved normal values by 30 and 180 days, respectively. The percentage of circulating and median absolute BPX-501 cells at Day 100 were 3.35% ± 2.94% (0 - 8.4%) and 29.09 ± 39.56 cells/ml (0 - 135 cells/ml), respectively. Conclusion These data indicate that the adoptive transfer of BPX-501 following αβ-T and B-cell depleted haplo-HSCT represents a novel and highly effective transplantation strategy for pediatric patients with FA. Further, despite the addition of BPX-501, low rates and severity of both acute and chronic GvHD was observed, a finding that could translate into significant long-term benefit, in terms of reduction of squamous cell carcinoma a well-known complication occurring in FA patients after HSCT. Disclosures Aldinger: Bellicum Pharmaceuticals, Inc.: Employment. Locatelli:Bellicum: Consultancy, Membership on an entity's Board of Directors or advisory committees; Miltenyi: Honoraria; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; bluebird bio: Consultancy; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees.

P080Correlation between the reject of haploidentical transplants in patients affected by hemoglobinepathies and the presence of donor-specific anti-HLA antibodies

Aim Allogeneic haematopoietic stem cell transplantation is the treatment of choice for both pediatric and adult patients with onco-haematological diseases and non-malignant disorders. It is well known that an HLA-identical family donor is available in about 25% of cases and it is not always possible to promptly identify a voluntary donor in international registries. In the absence of a HLA-matched donor, the transplantation strategy is increasingly orienting towards the choice of allogeneic hematopoietic stem cell transplantation alternatives, such as the use of haploidentical family donors. The aim of this study was to determinate the presence in the recipients of donor specific anti-Human leukocyte antigen of class I and/or class II antibodies an correlate their potential role with the high rate of graft rejection observed. Methods The plasma or the sera of 23 patients affected by hemoglobinepathies, treated with a haploidentical transplant, were analyzed using the Mixed Antigen assay kit and subsequently, in case of positivity, with the Single Antigen beads assay kit (One Lambda, California) by Luminex technology. Results In the group of 23 transplanted patients affected by hemoglobinopathies, 9 rejected the graft. Among these, 3 (33.3%) showed the presence of DSA, while only 1 out of 14 patients with complete chimerism (7.1%) was positive for Donor-specific HLA Antibody. The presence of non-specific donor anti-Human leukocyte antigen antibodies class I and/or II was also demonstrated in 6 of the 23 patients analyzed, 3 of which were included in the group of 9 who rejected the transplantat (33.3%). Conclusions Our data showed that the presence of specific-donor anti-HLA antibodies represents a parameter associated with a higher percentage of rejection in haploidentical hematopoietic stem cell transplantation performed in patients affected by hemoglobinopathies, although a wider cohort of patients needs to be analyzed before drawing any conclusion. With the contribution of Berloni T. Galluccio: 1. Grant/Research Support; Company/Organization; IME Foundation. 2. Consultant; Company/Organization; Andreani Marco. 4. Scientific/Medical Advisor; Company/Organization; Andreani Marco. 5. Employee; Company/Organization; Galluccio Tiziana. A. Di Luzio: 1. Grant/Research Support; Company/Organization; IME Foundation. 2. Consultant; Company/Organization; Andreani Marco. 4. Scientific/Medical Advisor; Company/Organization; Andreani Marco. 5. Employee; Company/Organization; Di Luzio Andrea. M. Battarra: 1. Grant/Research Support; Company/Organization; Andreani Marco. 2. Consultant; Company/Organization; Andreani Marco. 4. Scientific/Medical Advisor; Company/Organization; Andreani Marco. 5. Employee; Company/Organization; Mariarosa Battarra.

Haploidentical Allogeneic Hemopoietic Stem Cell Transplant for High Risk Myelodysplastic Syndrome

▪IntroductionAllogeneic hematoopoietic stem cell transplantation (HSCT) is the only today available curative treatment for Myelodysplastic Syndrome (MDS) patients. Wide approach to transplant has been hampered by HLA compatible donors availability, advanced diseases, donor and patients advanced age.In the recent years improvement of haploidentical HSCT has offered to many patients the opportunity to undergo this curative approach.The Genova transplant team included haplo HSCT for MDS in his standard operative procedure since 2011. Therefore this unselected consecutive patients cohort offers the possibility to verify feasibility of haplo HSCT in MDS patients.Patients and Methods.Form August 2011 since March 2016 thirty (30) consecutive patients were transplanted from an haploidentical donor in our center. All of them were lacking an HLA identical family donor and an 8/8 matched unrelated donor. Table 1 reports patients and disease characteristics.All donors were haploidentical family member. Conditioning regimen was myeloablative for 10 patients and reduced intensity for 20 patients as previously reports (Raiola et al Biol Blood Marrow Transplant. 2013; 1:117-22). Patients received a median of 3.1 x10e8 /kg (range 1.1 -6) un-manipulated marrow derived nucleated cells. Graft versus host disease (GvHD) prophylaxis consisted in post transplant cyclophosphamide 50 mg/kg , on day+3 and +5 , cyclosporine (from day 0) , and micophenolate (from day +1).Data are expressed and median with a range unless indicated. Disease free survival and GvHD rate are calculated with the methods of Kaplan and Meier.ResultsHematologic recovery was complete in 28 (93%) patients. The median times to neutrophil (>500/μL) and platelet recovery (>20,000/μL) was 18 days (range, 14-24 days) and 25 days (range, 12 - 51 days), respectively. Two patients had autologous recovery and were successfully re-transplanted with the same protocol. The incidence of acute GVHD grade II-IV was 15%. No early death was registered. Two patients died, in complete remission of MDS, at 389 (chronic GVHD + sepsis) and 1123 (interstitial pneumonitis) days after transplant, respectively.Seven patients relapsed at median time from transplant of 188 days (range 139 - 560 days). All relapsed patients subsequently died by disease progression.The incidence of chronic GVHD was 20% (6 patients, severe in 5). At the time of this report of the 21 surviving patients (all in remission by MDS) two are under chronic GvHD treatment.With a median follow up of 20.5 months (range 4 - 54) the 3 years probability disease free survival is 69% (95%, CI 51-87).DiscussionHaploidentical transplant, together with conventional donor approach, offers the majority of patients the possibility to undergo HSCT. The data here presented demonstrated feasibility of the procedure in advanced disease patients even by an haploidentical donor. In our knowledge no similar results are achievable by today available or experimental medical therapy. HSCT transplantation, even from haploidentical donor, should be offered to all MDS patients presenting with this indication. Disease relapse is the most important cause of transplant failure. [Display omitted] DisclosuresAngelucci:Novartis oncology, celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees.

HLA-Haploidentical TCR αβ/CD19-Depleted Hematopoietic Stem Cell Transplantation in Children with Fanconi Anemia

Introduction. Allogeneic HSCT currently represents the only consolidated curative approach for Fanconi anemia (FA) patients, with best results observed in the HLA-identical sibling setting. For patients lacking an HLA-matched related or unrelated donor, haploidentical HSCT virtually assures the opportunity for nearly all patients to benefit from HSCT, offering the advantage of immediate accessibility to the transplant procedure. In order to overcome the limitation of delayed immune recovery, historically associated with this type of allograft, in the last few years we developed a novel method of ex vivo graft manipulation, consisting of the negative depletion of T-cell receptor (TCR) αβ+ T-lymphocytes and CD19 B-cells from peripheral blood stem cells (PBSC) grafts (ClinicalTrial.gov identifier: NCT01810120) (Bertaina el al., Blood 2014). Here we report our analysis in a subgroup of FA patients given TCRαβ/CD19-depleted haploidentical HSCT at our Institution.Patients and methods. Ten consecutive FA patients (6 girls and 4 boys) underwent a TCRαβ/CD19-depleted HSCT from an HLA-haploidentical relative between September 2011 and July 2015. Median age at diagnosis was 6.6 (range 2.7-22.0) years and median age at time of transplantation was 8.1 (range 4.4-22.2) years. The conditioning regimen included Cyclophosphamide 300 mg/m2/day and Fludarabine 30 mg/m2/day for 4 consecutive days (days -6 to -3), with 200 cGy single-dose TBI. Pretransplantation Fresenius® ATG was administered at a dose of 4 mg/kg/day for 3 consecutive days (days -5 to -3) in order to prevent both graft failure and graft-versus-host disease (GVHD). All patients received Rituximab 200 mg/m2 to reduce the risk of Epstein-Barr virus-related post-transplant lymphoproliferative disorders. Selective removal of TCRαβ+ and B-cells was performed on G-CSF-mobilized donor PBSC through labeling with biotinylated anti-TCRαβ antibodies and anti-CD19 antibodies, followed by incubation with anti-biotin antibodies conjugated to paramagnetic beads (CliniMACS; Miltenyi Biotec, Bergisch Gladbach, Germany). No immunosuppressive therapy was administered as post-transplantation prophylaxis against GVHD.Results. The TCRαβ/CD19-depletedgrafts contained a median of 20.40 x106/kg (range 15.80-33.40) CD34+ cells, 5.60 x106/kg (range 1.78-69.60) CD3+ lymphocytes, 0.021 x106/kg (range 0.002-0.043) TCRαβ+ lymphocytes, 5.60 x106/kg (range 1.78-69.60) TCRγδ+ lymphocytes, 0.036 x106/kg (range 0.013-0.079) CD20+ lymphocytes, and 45.30 x106/kg (range 16.2-177.0) NK cells. Engraftment with sustained full donor chimerism was achieved in 9 out of 10 patients, the cumulative incidence of graft rejection being 10% (95% CI, 0-26.8). The patient who rejected his first allograft achieved a complete engraftment after a second HSCT from one-antigen mismatched unrelated donor. No secondary graft failures were observed. The median time for neutrophil and platelet engraftment was 12 days (range, 9-15) and 9 days (range, 8-12), respectively. No patient experienced acute or chronic GVHD in the follow-up period. No transplant-related deaths occurred in our cohort. With a median follow-up of 28 months (range 13.2-39.1), the Kaplan-Meier estimates of OS and DFS were both 100%, while the EFS probability was 90% (95% CI, 47.3-98.5).Discussion. These data suggest that haploidentical HSCT after removal of TCRαβ+ and CD19+ lymphocytes is able to guarantee engraftment with excellent OS and DFS in patients affected by FA. Moreover, given the very low incidence of both acute and chronic GVHD, which has been shown to contribute to the increased risk of developing late post-transplantation malignancies in FA patients, this approach can be considered a very attractive option for FA patients in need of an allograft and lacking an HLA-identical family donor. DisclosuresNo relevant conflicts of interest to declare.

Update on the safety and efficacy of retroviral gene therapy for immunodeficiency due to adenosine deaminase deficiency

AbstractAdenosine deaminase (ADA) deficiency is a rare, autosomal-recessive systemic metabolic disease characterized by severe combined immunodeficiency (SCID). The treatment of choice for ADA-deficient SCID (ADA-SCID) is hematopoietic stem cell transplant from an HLA-matched sibling donor, although <25% of patients have such a donor available. Enzyme replacement therapy (ERT) partially and temporarily relieves immunodeficiency. We investigated the medium-term outcome of gene therapy (GT) in 18 patients with ADA-SCID for whom an HLA-identical family donor was not available; most were not responding well to ERT. Patients were treated with an autologous CD34+-enriched cell fraction that contained CD34+ cells transduced with a retroviral vector encoding the human ADA complementary DNA sequence (GSK2696273) as part of single-arm, open-label studies or compassionate use programs. Overall survival was 100% over 2.3 to 13.4 years (median, 6.9 years). Gene-modified cells were stably present in multiple lineages throughout follow up. GT resulted in a sustained reduction in the severe infection rate from 1.17 events per person-year to 0.17 events per person-year (n = 17, patient 1 data not available). Immune reconstitution was demonstrated by normalization of T-cell subsets (CD3+, CD4+, and CD8+), evidence of thymopoiesis, and sustained T-cell proliferative capacity. B-cell function was evidenced by immunoglobulin production, decreased intravenous immunoglobulin use, and antibody response after vaccination. All 18 patients reported infections as adverse events; infections of respiratory and gastrointestinal tracts were reported most frequently. No events indicative of leukemic transformation were reported. Trial details were registered at www.clinicaltrials.gov as #NCT00598481.

Allogeneic Stem Cell Transplantation for Refractory Acute Myeloid Leukemia in Pediatric Patients: The UK Experience

INTRODUCTIONThe prognosis for children with refractory acute myeloid leukemia (AML) treated with chemotherapy is dismal and data on the outcome after allogeneic haematopoietic stem cell transplant (SCT) are scanty with reported leukemia free survival (LFS) rates of 10-20%. Thus there is significant controversy about whether SCT is appropriate in such patients (pts). We performed a retrospective, national study to analyse outcomes and prognostic factors for children undergoing SCT for refractory AML in the UK.METHODSA retrospective analysis of all pts <18 years of age reported to the BSBMT registry who received their first allogeneic SCT between 2000-2012 for refractory AML (ie >5% blasts in the bone marrow (BM) or proven extramedullary disease (EM) was performed. Source data verification (SDV) was performed to ensure pts were indeed refractory. The primary end-point was 5 year LFS. Secondary end-points were Relapse Rate (RR), Treatment Related Mortality (TRM), Graft Versus Host Disease (GVHD) and Overall Survival (OS). The Kaplan Meyer method was used to estimate survival data and Fisher's exact and Mantel-Cox Log Rank tests were used to compare disease- transplant- and survival-related variables.RESULTSFollowing SDV, a total of 44 pts from 13 centres were included in the study. The median age at SCT was 11.5 yrs and the median number of prior lines of chemotherapy was 3. The median time from diagnosis to SCT was 197 days. 23 pts had primary refractory AML and 21 had relapsed refractory AML. 12 pts showed adverse risk cytogenetics, 26 standard risk and 6 favourable. EM disease was documented in 5 pts. 42 children had >5% myeloid blasts in the BM immediately prior to conditioning and refractory disease was confirmed by cytogenetics/molecular genetics in 23. 2 pts were in BM remission but had frank EM disease. 38 pts (86%) received myeloablative conditioning (14 TBI based) and 6 (14%) had reduced intensity conditioning (RIC). In vivo T cell depletion was used in 25 pts. 15 pts (35%) were transplanted from an HLA identical family donor, 15 from a matched unrelated donor and 14 (32%) a mismatched donor. BM was used as the stem cell source in 18 (41%), peripheral blood in 20 (46%) and cord blood in 6 cases (14%). Median follow up was 4 years 10 months.5 pts never achieved engraftment and had disease progression. The remaining 39 pts engrafted at a median of 15 days post-SCT. 30 pts (68%) achieved a complete remission (CR) following SCT. TRM at 1 year was 18% (5 infections, 1 cardiac failure, 1 GVHD-related). Acute GVHD occurred in 23 pts and was severe (grade ≥III) in 8 (19%). The incidence of chronic GvHD was low (1 limited, 2 extensive). Relapse was the major cause of treatment failure and occurred in 17 pts (39%) at a median 2.3 months post SCT. At last follow-up, 18 pts remain alive and in continuous complete remission (CCR). In this cohort, the 5 year OS and LFS were both 43% (95%CI 31-61%) (Figure1). Outcomes in pts with primary refractory disease (9/23, 39% in CCR) and those with relapsed refractory AML (9/21, 43% in CCR) were equivalent. Outcome for pts with cytogenetic confirmation of refractory disease was not statistically different (7/23, 30% in CCR) from the overall group. Pts transplanted with ≤30% blasts in the BM had improved outcomes (5-year LFS 52% vs 27%, p= 0.05). Likewise, the development of aGVHD of any grade was associated with a significantly better LFS (5-year LFS 56% vs 30%, p= 0.05). Cytogenetics including monosomy 7 (n=7) and molecular risk classification did not translate into a significant prognostic factor for relapse. Since RIC was used in only 6 pts, the impact of the intensity of conditioning cannot be determined.CONCLUSIONSThis is the largest series of outcomes for SCT for refractory paediatric AML reported to date. Our data indicate that for selected pts, particularly those with a lower disease burden, SCT offers a realistic chance of salvage in both primary refractory and relapsed refractory AML (5 year LFS 43%) with acceptable toxicity. The association of aGVHD with improved LFS suggest a possible role in engineering a graft-versus-leukemia effect in this patient group. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Long-term outcomes of granulocyte colony-stimulating factor-combined conditioning in allogeneic hematopoietic stem cell transplantation from HLA-identical family donors for myeloid malignancies

Dormant leukemia cells, which might escape the cytotoxic effect of conditioning before hematopoietic stem cell transplantation (HSCT), could be induced to enter the cell cycle by granulocyte colony-stimulating factor (G-CSF) and become more susceptible to the cell-cycle-specific agent cytarabine arabinoside (Ara-C). Based on this effect, we have utilized G-CSF-combined high-dose Ara-C in myeloablative conditioning for allogeneic bone marrow or peripheral blood stem cell transplantation from HLA-identical family donors since 1988. We report on the long-term outcomes of allogeneic HSCT using a conditioning regimen of 12Gy total body irradiation and G-CSF-combined high-dose Ara-C in 89 adult patients with acute myeloid leukemia, chronic myelogenous leukemia, or myelodysplastic syndrome. With a median follow-up of 135 months, the probability of overall survival and cumulative incidence of relapse at 5 years were 67.8% and 19.4%, respectively. In multivariate analysis, disease status at HSCT was associated with survival and relapse. These data demonstrate that G-CSF-combined myeloablative conditioning could be safely and effectively used for patients with myeloid malignancies.

Post-Transplant Cyclophosphamide Following a Myeloablative Conditioning For Hematologic Malignancies Receiving An Unmanipulated Haploidentical Bone Marrow Transplant

BackgroundUnmanipulated family haploidentical transplants are becoming increasingly used in patients lacking an HLA identical family donor, or a well matched unrelated donor. Aim of the studyThis is an updated analysis of our program of haploidentical bone marrow transplant (hBMT) , followed by post-transplant high dose cyclophosphamide (PT-CY) in 95 patients with hematoloigic malignancies receiving a myeloablative conditioning. MethodsThe conditioning regimen consisted of thiotepa, busulfan, fludarabine (TBF) (n=47) , thiotepa melphalan fludarabine (n=5) , or 9.9-12 Gy TBI + fludarabine (n=43). The patients' median age was 49 years (17-74); the disease status at the time of transplant, was first complete remission (CR1, n=29) , CR2 (n=23), or active disease (n=38,40%). The diagnosis was AML (35%), ALL (24%), MDS (12%) myeloproliferative disorders (12%), other malignancies (17%). The total nucleated cell dose infused was 3.37 (1.4-9.17). The median follow up for surviving patients is 440 days (90-930). Graft versus host disease (GvHD) prophylaxis consisted in PT-CY on day+3 and +5 , cyclosporine (from day 0) , and mycophenolate (from day +1).▪ ResultsThe cumulative incidence of neutrophil (PMN) engraftment was (90%) and all surviving patients on day +30 had full donor chimerism. The median day for neutrophil engraftment was day +17 (11-32). The cumulative incidence (CI) of grade II-III acute GvHD was 14%, and of moderate chronic GvHD 8%, severe cGvHD 9%. The CI of transplant related mortality (TRM) is respectively 7%, 17%, 26% for patients in CR1, CR2, or with active disease. The CI of relapse is respectively 17%, 30%, 37% for patients in CR1, CR2, or with active disease. The overall actuarial survival is respectively 75%, 44%, 32% for patients in CR1, CR2, or with active disease (p=0.002) (Fig.1). The most frequent cause of death was leukemia (26%) followed by infections (9%). ConclusionsThese data confirm our first report on 50 patients and support the use of myeloablative conditioning regimens, followed by h-BMT with PT-CY. The risk of acute and chronic GvHD seems relatively low , as well as the overall transplant related mortality. We have not seen the excess relapse rate reported when patients are given a non myeloablative regimen, and disease control has been satisfactorily both for patients in remission, as well as for patients with active disease at the time of transplants. Disclosures:No relevant conflicts of interest to declare.

Impact of Graft-Versus-Host Disease On Relapse After Allogeneic Hematopoietic Stem Cell Transplantation, an EBMT Megafile Study

AbstractAbstract 469 Background:After allogeneic HSCT, graft-versus-host disease (GvHD) occurs through recognition of minor or major histocompatibility mismatches by donor derived T lymphocytes. The same mechanism also operates in the elimination of residual malignant cells (the graft-versus-leukemia or GvL effect). Earlier studies have already shown reduced relapse risks for patients developing GvHD (Weiden et al, NEJM 1979; Horowitz et al, Blood 1990). In particular, a large study in CML patients (Gratwohl et al, Blood 2002) showed that increasing grades of acute and chronic GvHD are associated with a proportional decrease in relapse risk. Incidence and severity of acute and chronic GvHD might therefore be used as surrogate markers for GvL effects.Transplant procedures have changed significantly since these publications. Increased use of unrelated donors, peripheral blood as stem cell source, and the introduction of reduced intensity conditioning regimens might affect the relationship between GvHD and GvL. Furthermore, previous studies have only analyzed transplants for AML, ALL and CML, the prevailing transplant indications at the time. Today, many patients receive transplants for MDS, plasma cell disorders (PCD) or lymphoma. We hypothesized that comparing the effect GvHD on relapse incidence might provide a useful surrogate marker for the susceptibility of different diseases to allo-immune effects. Methods:We studied 48,111 first allogeneic transplants carried out and reported to EBMT between 1998 and 2007. The impact of GvHD on relapse risk was assessed by including acute and chronic GvHD as time-dependent covariates in Cox models for cause-specific hazards adjusted for patient age, year of transplant, donor type, stem cell source, and type of conditioning regimen. Results:Diseases were CML (N=7,711), AML (14,539), ALL (6,802), MDS/MPN (6,958), lymphoma (N=8,231), or PCD (3,870). Donors were HLA identical family donor (N=28,030), and HLA-identical unrelated donors (N=14,422) or mismatched donors (N=5,659). Stem cell source was bone marrow (N=13,273), peripheral blood (N=34,022), or cord blood (N=816). Conditioning intensity was myeloablative (N=28,843), reduced intensity (15,889) or unknown (N=3,379). 14,764 (31%) of grafts were T-cell depleted.Incidence of grade I-IV acute GvHD was 49%, that of grade II-IV acute GvHD 30%. Limited chronic GvHD was diagnosed in 17% and extensive chronic GvHD in 20% of patients. Incidence of disease relapse was 22%, 28%, and 31% at 1, 2, and 4 years respectively.As shown previously, development of GvHD was associated with a reduced risk of relapse in our data. In CML, a clear reduction of relapse risk occurred with hazard ratios declining proportionally to severity of both acute and chronic GvHD (Figure 1). The protective effect of severe acute (grade III-IV) GvHD was similar to that of extensive chronic GvHD, whereas the protective effect of mild acute (grade I-II) GvHD was comparable to that of limited extensive GvHD. ALL was almost equally sensitive to GvHD as CML, whereas MDS/MPN and lymphomas showed intermediate sensitivity (Figure 1). Acute and limited chronic GvHD were only associated with modest reductions in relapse risk in AML and PCD.The limited sensitivity of PCD to allo-immune effects was also evident in Kaplan-Meier curves of disease-free survival where – in contrast to other diseases – no plateau developed during follow-up (Figure 2, upper panel). Similarly, hazard rates of disease relapse failed to drop to values near zero in patients with PCD (Figure 2, lower panel). Interestingly, despite a comparatively poor association of GvHD and relapse in AML patients, a plateau in the survival curve occurred and hazard rates dropped in parallel to other diseases, suggesting that curative GvL effects operating independently of GvHD might occur in this disease. Discussion:These data confirm earlier observations of a potent GvL effect associated with GvHD. While GvHD and GvL are significantly associated in all diseases, the strength of this association strongly differs between disease entities (strongest correlation in CML and ALL, weakest correlation in AML and PCD). A poor correlation might point to either insensitivity of a particular disease to GvL effects, to GvL effects operating in the absence of and independent from GvHD, or to a significant fraction of patients already cured before allogeneic SCT. [Display omitted] [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Thrombotic complications without evidence of hemolysis in paroxysmal nocturnal hemoglobinuria: is eculizumab indicated?

Dear Editor, We would like to discuss the treatment of paroxysmal nocturnal hemoglobinuria (PNH) by presenting the fatal outcome of one of our patients with this disease. A 30-year-old Caucasian man with a history of auto-immune hepatitis developed pancytopenia. He had no complaints and did not take any medication. On physical examination, a pale man was seen without any other remarkable findings. His hemoglobin was 8.3 g/dL (13.8–16.9 g/dL), leucocytes 0.30 (neutrophils 0.2) × 109/L (3.5–10 × 109/L), platelet count 16 × 109/L (150–350 × 109/L) and reticulocytes 8.4 × 109/L (30–95 × 109/L) without signs of hemolysis. Bone-marrow biopsy showed reduced cellularity (10 %) without any other (including cytogenetic) abnormalities. In peripheral blood, glycosylphosphatidylinositol (PI)-deficient clones were detected in 34, 27, and 1 % of the granulocyte, monocyte, and erythroid lineages, respectively. Severe aplastic anemia (SAA) was diagnosed secondary to PNH. Lacking an HLA-identical family donor, standard treatment with immunosuppression was started: rabbit anti-thymocyte globuline, methylprednisolone, and cyclosporine. This resulted in a partial response 3 months later: persistent transfusion-dependent anemia without signs of intravascular hemolysis, thrombocytopenia, and a normal leucocyte count. An expansion of the PI-deficient clones up to 86, 86, and 7 % of the granulocyte, monocyte, and erythroid lineages, respectively (Fig. 1) was noted. Fig. 1 PNH clones at diagnosis (a) and their expansion (b) after treatment for SAA. Comparison of the PI-deficient clones at diagnosis of severe aplastic anemia (a) and after triple immunosuppression (b). Monocytes and granulocytes were gated based on scatter ... Three months after initial presentation, he was re-admitted to hospital because of abdominal pain and bloody stools. Thrombosis of the superior mesenteric vein was diagnosed and anticoagulant therapy was instituted with nadroparin 15,200 IU/day subcutaneously. Eculizumab treatment was considered, but because of the complete absence of intravascular hemolysis, the effect of the anticoagulant therapy was awaited. Subsequently, he developed headache and a left hemiparesis. Repeated CT scans of the brain showed expanding ischemic areas parieto-occipital with secondary bleeding, and the patient finally died. Thrombosis is the most feared and life-threatening complication in PNH patients, because after onset, it is frequently progressive and refractory to anticoagulant therapy [1, 2]. The mechanism of thrombotic complications in PNH is not completely understood, but it has mainly been attributed to intravascular hemolysis [1]. Experimental studies show that the free plasma hemoglobin liberated during hemolysis scavenges nitric oxide (NO). As a result, NO depletion produces dystonia and spasm of the smooth muscle, suppresses the anti-inflammatory effect on the endothelium and promotes platelet activation and thrombosis [3]. Eculizumab is a monoclonal antibody that binds complement factor C5, thereby inhibiting complement activation on erythrocytes and reducing hemolysis. As a result, eculizumab decreases thrombotic risks in PNH patients [2, 4, 5]. Interestingly, our patient suffered from progressive abdominal and cerebral thrombotic complications without any signs of intravascular hemolysis. It is also possible that the pathogenesis of thrombosis in PNH might be caused by other mechanisms associated to complement activation and not directly related to hemolysis [1, 6]. We speculate that the mechanism of thrombosis could be associated to platelet activation caused by the absence of CD59 and CD55 on the platelet surface [7, 8]. Internationally accepted indications for eculizumab treatment include transfusion-dependent hemolysis (four or more transfusions in 12 months) and PNH-related complications (i.e., thrombosis or renal failure) regardless of transfusion history [3]. Although no clinical data are available, eculizumab could be indicated in patients with thrombotic events in the absence of hemolysis [5, 9, 10].

Overview of the Current Issues and Advances in Haemopoietic Stem Cell Transplantation for β-thalassemia Major

Bone marrow transplantation (BMT) is the only possible curative treatment for β-thalassemia major. The largest experience occurred in Pesaro, Italy, where the BMT was applied after a standard risk assessment. The patients were divided into 3 risk classes based on liver size by physical examination, the presence or absence of fibrosis by liver biopsy, and adherence to regular iron chelation. Outcomes were mainly affected by the risk status. After modifications to the conditioning regimens, the risk of transplantation-related complications in highrisk recipients reduced considerably. As a result, outcomes after transplantation have become more similar across risk categories. For BMT, most centers use bone marrow instead of peripheral blood in thalassemia. Some studies showed that peripheral blood stem cell transplantation (PBSCT) is better than BMT with regard to hematologic recovery, hospitalization period, leukemia-free survival, overall survival (OS), and transplant-related mortality (TRM). No significant differences were seen in grade II to IV acute GVHD (aGVHD); but the incidence of chronic GVHD (cGVHD) was significantly higher in the PBSCT group. BMT from unrelated donors may offer similar results to those obtained using HLA-identical family donors, at least for patients who are not fully compliant with conventional treatment and do not yet show severe complications of iron overload. All studies conclude that MUD BMT might be a good alternative for patients with less risk factors. Another study concluded that, at present, due to high graft failure and GVHD rates, BMT from alternative donors should be restricted to patients who have poor life expectancies because they cannot receive adequate conventional treatment or because of alloimmunization to minor blood antigens. In another study unrelated cord blood transplantation (CBT) was compared to related donor transplantation for children with β-thalassemia. The results were comparable to the survival rates of related-donor BMT for thalassemia. It has always been a dream for parents to have a new baby who might be a donor for his/her sibling and save his/her life. Today some families tried to learn the HLA group of the fetus using prenatal diagnosis. The last step in this development was preimplantation genetic diagnosis (PGD). PGD has become available as an alternative to prenatal diagnosis in order to avoid the risk for pregnancy termination, because PGD allows selection of unaffected embryos before a pregnancy is established. Gene therapies, the ultimate idea, involves replacing allogeneic stem cell transplantation with the transfer of normal globin genes into patientderived autologous haematopoietic stem cells, bypassing the need for allogeneic donors and the immunosuppression required to achieve engraftment of the transplanted cells and to eliminate the risk of donor-related graft-versus-host disease. The successful preclinical studies in thalassaemia mousemodels, the accumulating data on lentiviral vector-mediated HSC transduction and the anticipated increased safety of lineage-restricted globin SIN lentiviral vectors strongly support the initiation of Phase I gene therapy clinical trials in β-thalassaemia.

Feasibility and outcome of haploidentical SCT in pediatric high-risk hematologic malignancies and Fanconi anemia in Uruguay

In total, 17 pediatric patients with hematologic malignancies (n=14) and Fanconi anemia (FA) (n=3) underwent haploidentical SCT with T-cell depletion. The patients were conditioned with reduced-intensity regimens, and CYA was used for GVHD prophylaxis. Successful engraftment occurred in 16 patients (94%). One patient failed to achieve a primary engraftment. Another patient rejected the first SCT after 10 weeks and had a successful second transplant. Of all engrafted patients, only one developed severe acute GVHD. Ten patients were alive at a median follow-up of 18 months (range, 5-62 months). The 5-years' OS was 53.8%. The three patients with FA are currently well with full-donor chimerism at 16, 6 and 5 months post transplant, respectively. The OS of 14 patients with high-risk hematologic malignancies was 47.6%. Three patients died as a result of post transplant leukemia relapse. CMV infection, GVHD and organ injury were other causes of mortality. Haploidentical SCT was found to be an alternative feasible treatment in Uruguay for patients who need allogenic transplantation but lack an HLA-identical family donor. It should be considered as an early option in FA patients before transformation or significant exposure to blood products.