Peripheral Blood Stem Cell Grafts Research Articles

Impact of Postremission Consolidation Chemotherapy On Outcome After Reduced-Intensity Conditioning (RIC) Allogeneic Stem Cell Transplantation (allo-SCT) for AML in First Complete Remission (CR1): A Report From the Acute Leukemia Working Party of EBMT.

AbstractAbstract 3098The role of consolidation therapy after successful remission induction is well established in the treatment paradigm of patients with AML in the non-transplant setting. Most contemporary treatment protocols for young AML patients not transplanted in CR1 include repetitive cycles of high-dose cytarabine. However, in the standard myeloablative allo-SCT setting, consolidation therapy prior to transplant did not prove to have a beneficial impact on overall survival (OS), leukemia free survival (LFS) or relapse incidence (RI) as shown in 2 previous studies from the IBMTR and EBMT. In the context of RIC and non-myeloablative (NMA) allo-SCT, this picture might be different since one may speculate that consolidation therapy prior to transplantation may allow for reducing the incidence of relapse while waiting for the GVL effect. Nevertheless, the value of consolidation prior to RIC and NMA allo-SCT in AML in CR1 has not yet been explored.Thus, this multicenter retrospective analysis aimed to assess the role of consolidation prior to RIC/NMA allo-SCT in a cohort of AML CR1 patients (n=789) who received HLA-identical (n=564) or MUD (n=225) peripheral blood stem cell grafts between 2000 and 2010 and who were reported to the EBMT registry. Patients who required more than 2 cycles of induction to achieve CR were excluded. In this cohort, 591 patients received at least one course of consolidation and 198 patients did not receive any consolidation before SCT. With a median follow-up of 40 months (range, 1–140), the Kaplan-Meier estimates of OS and LFS at 3 years were 55% (95%CI, 52–59%) and 52% (95%CI, 48–55%), respectively. The cumulative incidence of relapse was 33% (95%CI, 29–36%). The median time from CR to allo-SCT was longer among patients who received consolidation compared with patients who received no consolidation (4.7 vs. 2.2 months; p<0.001). Of note, patients who received consolidation and who were transplanted beyond the median time between CR and transplantation, had an improved 3-year LFS compared with patients who received consolidation and transplanted within the median time (58+/−2 vs. 47+/−3, p=0.002). This was due to a lower RI in the group of patients transplanted beyond the median time (28+/−2% vs. 38+/−3%, p=0.009), irrespective of the number of consolidations they received, suggesting a possible selection bias of patients surviving longer without relapse before allo-SCT.With this background, we elected to focus on the group of 373 patients who were transplanted within the median time frame between CR achievement and allo-SCT (3 months for sibling donors and 4 months for MUDs). In this subgroup, 151 did not receive any consolidation and 222 received ≥1 consolidation (1 course, n=164, ≥ 2 courses, n=58).Patients who did not receive any consolidation were older (58 vs. 56 y, p=0.03), had a shorter time from CR to transplantation (56 vs. 71 days, p<0.001), needed more often 2 induction cycles to achieve CR (80% vs. 35%, p<0.001), and received more often TBI based conditioning (57% vs. 23%, p<0.001). Factors such as transplantation year, patient gender, cytogenetics risk group, donor type (MUD vs. sibling), and female donor to male recipient, were not significantly different between groups. With a median follow-up of 40 months (range, 1–140), the 3-year cumulative incidences of relapse were not significantly different between groups: 36±4% for patients with no consolidation and 38±3% for patients with consolidation (p=0.89). In addition, LFS was similar between groups, 45±4% and 47±3%, respectively (p=0.41). Doses of cytarabine given as consolidation had no influence on RI. By multivariate analysis adjusting for patient age, cytogenetics risk group, number of induction cycles, time from CR to transplantation, donor type, and conditioning regimen category, performing pre-transplant consolidation (0 vs. ≥1 cycle) had no significant impact on RI (HR=1.12, 95%CI, 0.74–1.70, p=0.58), or LFS (HR= 0.90; 95%CI, 0.64–1.27, p=0.90).In all, this retrospective study did not find any impact of postremission consolidation on outcome of patients with AML in CR1 who underwent allo-SCT with reduced-intensity or NMA conditioning. However, further investigation of high-risk subpopulations and well designed prospective controlled studies are warranted. Disclosures:No relevant conflicts of interest to declare.

Chemotherapy-Only Preparative Regimen for T-Cell Depleted Hematopoietic Stem Cell Transplantation of Patients with Fanconi Anemia From Alternative Donors

AbstractAbstract ▪3471▪This icon denotes a clinically relevant abstractFanconi anemia (FA) is associated with a high risk of secondary malignancies, more specifically solid tumors. In allogeneic stem cell transplantation of the “non-Fanconi anemia host”, two factors have been consistently associated with increased risk of secondary malignancies post transplant and include graft-versus-host disease (GvHD) and radiation. The goal of reducing the risk of GvHD post transplant, has been achieved successfully with T-cell depleted transplants, as previously reported.Our second aim was to reduce the risk of radiation toxicity post transplant. We therefore initiated a multi-center trial using the fludarabine (Flu)/cyclophosphamide (Cy)/ATG cytoreduction backbone, and substituting busulfan (Bu) instead of radiation. This was followed by a CD34+ T-cell depleted peripheral blood stem cell graft. From June 2009 to July 2012, 27 patients, including 13 males and 14 females aged 4.3 – 31.4 (median 8.1), enrolled on this phase II multicenter protocol in 4 institutions.Indications for transplant included severe single lineage cytopenia (N=3), aplastic anemia (N=18) and myelodysplastic syndrome (N=6) - including refractory anemia RA (N=3), RA with excess blasts 1 RAEB1 (N=2), RAEB-2 (N=1). Prior treatment included transfusions (N=27) and androgens (N=12). Ten patients had a history of prior infections. Donors were Related mismatched (N=6) or Unrelated matched (N=16) or mismatched (N=5).Preparative regimen was: Bu 0.8–1.0 mg/Kg/dose Q 12H × 4 doses (days -7, -6), Cy 10 mg/Kg/day × 4, Flu 35 mg/m2/day × 4 days and Rabbit ATG 2.5 mg/Kg/day × 4 days (days -4 to -2). Patients also received filgrastim and GvHD prophylaxis with cyclosporine. Busulfan doses were adjusted to keep the steady state concentration below 350 in most cases. All grafts were T-cell depleted using the CliniMacs CD34 columns (Miltenyi). Cell doses of the grafts were: 3.1–42.7 × 106′ CD34 cells/Kg and 2.2–49.9 × 103′ CD3 cells/Kg.All 27 evaluable patients engrafted; one patient suffered a secondary graft failure. Two patients developed grade 1 and only one patient developed grade 2 GvHD. Grade 2–4 toxicity included mucositis (N=10), pulmonary toxicity (N=6), hepatotoxicity (N=6) with one patient developing hepatic veno-occlusive disease, renal toxicity (N=5), and hypertension (N=7). Infections included: CMV viremia (N=4), EBV viremias (N=1), clostridium difficile (N=1), bacteremia (N=5) and clostridium botulinum (N=1). Cause of death for four patients was acute respiratory failure (N=1), multi-organ failure (N=1), severe pulmonary hypertension (N=1) and infection (N=1). With a median follow-up of 7.9 months (range 0.5–37.8 months) 19 of 23 evaluable patients are alive and well (4 pts too early for outcome analysis).Although the study is ongoing an includes a relatively small number of patients with modest follow-up, the results appear promising. Engraftment, GVHD, early toxicity, infection and outcome data appear similar to historical TBI-based protocols. Further enrollment and longer follow up will define the comparative toxicity profile and relative risk of second tumor. Disclosures:Williams:bluebird bio: Consultancy; Wyeth: ; Takara bio:.

Fully Automated Washing of Cryopreserved Peripheral Blood Stem Cells (PBSC): Results of a Prospective, Multicenter, Clinical Trial.

AbstractAbstract 3164 Background.Cryopreservation of Hematopoietic Stem Cells (HSC) is a standard procedure for both allogeneic cord blood and autologous HSC transplantation. PBSC are routinely used for the latter; the graft is usually thawed bedside and shortly reinfused without any manipulation. Infusion-related toxicity is usually mild, although severe reactions have been reported, mostly in patients with co-morbidities at baseline. Indeed, cell viability decreases over time after thawing. Washing the thawed graft was reported to improve both clinical tolerance and cell viability. It is however not routinely carried out as it is time-consuming and may result in clinically relevant HSC loss. The fully automated solution SmartWash™ (Biosafe, Switzerland) is designed to wash a thawed graft in a clinical setting. We report here its validation through an international, prospective, multicenter trial. Methods.A pre-clinical and a clinical study were designed and sequentially carried out in 4 European Centers (Basel, Florence, Marseille and Murcia) to assess the reproducibility and feasibility of the SmartWash™ system. During the pre-clinical phase, 10 PBSC Units/Center (total: 40 procedures) from patients who permanently lost the indication to the transplant were thawed and split in two aliquots: one was washed and the other was left unmanipulated. A shared protocol targeted to assess recovery, viability and stability of thawed PBSC at different time-points was developed; in particular, an ISHAGE-modified flow cytometry method was implemented in order to improve the evaluation of thawed CD34+ cells. Clinical grade hydroxyethyl starch (Voluven® 6%,Fresenius, Germany) was validated and used as washing solution. Following the validation of the method, a prospective, observational clinical trial was started after approval of the competent Authorities. Twenty-five consecutive patients across the 4 Centers underwent an autologous PBSC transplantation according to the local practice and indications; all the grafts were washed by Smartwash™. Cellular recovery, clinical tolerance and transplant outcome were collected according to a shared protocol. Results.All the washing procedures were completed without any laboratory problems in the participating centers. In the pre-clinical study the recovery of total CD34+ cells in the washed product was 101.2%±27.0 as compared to the pre-freezing value, with a viability of 87.2%±10.0, always showing an advantage over the unwashed samples at all considered time-points (0,1,4 and 24 hours after washing, respectively, Fig. 1). The workload of the procedure, as compared to the unwashed process, resulted in a 40 minutes prolongation for each thawed product, among which only 12 minutes were devoted to active time work, whilst 28 minutes consisted in automatic processing.In the clinical trial, patients received a median of 4.32×106 CD34+ cells/Kg (1.32–27.92), as measured before cryopreservation. Recoveries of both total and viable CD34+ cells after thawing and washing are reported in the Fig. 2, replicating the results of the pre-clinical study. Infusion-related toxicity was negligible (1 grade-1 toxicity out of 25 patients). All patients achieved both neutrophil and platelet sustained engraftment at a median of 11 (9–19) and 13 (7–19) days, respectively. Conclusions.SmartWash™ is an efficient and safe automated method to wash thawed PBSC grafts in a closed, clinical-grade system. Its feasibility and reproducibility was confirmed in an international, multicenter, clinical study. The washed product is stable and clinically feasible for several hours after thawing. [Display omitted] [Display omitted] Disclosures:Saccardi:Biosafe SA: Research Funding. Boieri:Biosafe SA: Research Funding. Loutan:Biosafe SA: Employment.

Bone Marrow Mixed Chimerism Is a Risk Factor for Relapse After T-Cell Depleted Allogeneic Stem Cell Transplant

AbstractAbstract 4145 Background:Full donor chimerism following non myeloablative unmodified stem cell transplants (SCTs) is important for disease control and SCT outcome. The impact of mixed chimerism (MC) after myeloablative unmodified SCT remains controversial, and there are limited reports about its prognostic significance after T-cell depleted (TCD) SCT. Treatment of MC, including reduction of immunosuppression or infusion of donor leucocytes (DLI), can lead to the development of graft versus host disease (GVHD). In order to optimize the graft vs leukemia (GVL) effect of a TCD allograft while minimizing GVHD risk, we sought to determine the significance of MC on TCD SCT outcomes and to identify a subgroup that would benefit from intervention. Methods:From 2000–2010, 447 adult patients with acute myeloid and lymphocytic leukemia (AML, ALL) and myelodysplastic syndrome (MDS) underwent bone marrow (BM) or peripheral blood stem cell (PBSC) TCD SCT. Conditioning regimens were total body irradiation (TBI)/Thiotepa with Cyclophosphamide or Fludarabine, Clofarabine/Melphalan/Thiotepa or Busulfan/Melphalan/Fludarabine. Like-gender donor-recipient chimerism was analyzed using semi-quantitative PCR for polymorphisms; PCR and/or cytogenetics were used for unlike gender pairings. Relapse was cytogenetic or hematologic evidence of disease. BM chimerism and disease status were evaluated at approimately 6, 12, 18 and 24 months. BM chimerism and outcome data were reviewed to determine whether 6 month BM MC (defined as < 95% donor chimerism) was associated with 2 year post-SCT relapse, transplant-related mortality (TRM) and disease-free survival (DFS). The 6 month landmark was chosen as a reasonable time point for intervention, such as DLI, if needed. Patients who received DLI prior to landmark were excluded. Patient and SCT characteristics were compared using Wilcoxon’s rank-sum test or Fisher’s exact test. DFS was estimated using Kaplan-Meier methods, and time-to-relapse and TRM were estimated using cumulative incidence functions. Results:300 of the 447 patients survived, were disease free, and had BM chimerism data at 6 months. Median age was 50.6 years. Most patients received PBSC grafts (89%). 131 (44%) and 9 (3%) related, and 86 (29%) and 74 (24%) unrelated donors, were matched and mismatched, respectively. Only patients in remission or with low level disease (BM blasts < 10%) were transplanted with TCD grafts. The majority of patients were conditioned with Busulfan/Melfalan/Fludarabine and TBI/Thiotepa/Fludarabine, 45% and 32%, respectively. 251 pts (84%) received antithymocyte globulin. 25% demonstrated MC in the BM at 6 mos. The majority (60%) with MC had a donor component of 75–95%. Diagnosis was not associated with MC at 6 months. Stem cell source and degree of HLA-match had no impact on BM chimerism. There was a significant difference in chimerism based on donor-recipient gender pairing (P = 0.04): male grafts into female patients having the greatest risk of MC and female grafts into female patients having the least. There was also a significant difference in the degree of chimerism based on conditioning regimen: Busulfan/Melphalan/Fludarabine was most likely to result in MC (P = <0.001). TRM was not significantly different between the mixed and full donor chimerism groups. However, relapse was significantly higher in the MC group (P = 0.03): 10% (95% CI: 6–14%) with full chimerism and 18% (95% CI: 7–28%) with MC at 2 years (Figure 1). Diagnosis had no impact on relapse among patients with MC. Conclusions:25% of TCD SCT recipients had MC in the BM. Although the incidence of relapse was low for patients who survived to 6 months in the full and MC groups (10% and 18%, respectively), the difference was statistically significant. There was also a significant difference in incidence of MC based on conditioning regimen and donor-recipient gender pairings. The low percentage of relapse in the MC group precluded subset analyses to identify a group who would benefit from the GVL effect of DLI. Lineage-specific PB chimerism analysis is ongoing and may provide information about subgroups that would benefit from intervention for MC. Analyses of outcomes, i.e., GVHD, in recipients of DLI or TCD stem cell boost for MC may help to determine the risk-benefit ratio of such interventions. [Display omitted] Disclosures:Goldberg:SOBI Biovitrum: Research Funding. Perales:SOBI Biovitrum: Research Funding.

Cord Blood Graft Engineering

Once considered solely medical waste and routinely discarded as part of the afterbirth, umbilical cord blood (CB) is now commonly used as a source of hematopoietic stem cells (HSCs) for patients in need of HSC transplantation (HSCT) (or, as more commonly referred to, bone marrow transplantation) for the treatment of both malignant and nonmalignant disorders. In fact, more than 20,000 CB transplantations (CBTs) have been performed since the first one in 1988 [1], and this number increases annually as more recent data demonstrate outcomes for CBT recipients paralleling those for conventional HSCT recipients. Numerous factors make CB a desirable source of HSCs, including ease of procurement and lack of donor attrition, with the ability to process and store the donor cells long term [2]. Importantly, CB donors can be used without the need for a “perfect” HLA match, thereby increasing donor access to HSCT, particularly for minority and mixed ethnicity patients, for whom a suitably matched related or unrelated donor may be difficult to locate. Moreover, despite the greater degree of HLA mismatch, CBT recipients are at decreased risk of developing chronic graft-versus-host disease (GVHD). The first decade of CBT experience was important in defining critical total nucleated cell (TNC) and CD34+ cell dose thresholds required for acceptable clinical outcomes, and in moving from related to unrelated donor CBT and from pediatric to adult patients. The limitations of this approach also were defined during this period, with low cell dose identified as the critical barrier. CBT recipients receive on average only 10% of the CD34+ stem/progenitor cells provided in conventional bone marrow grafts and only 5% of those provided in peripheral blood stem cell grafts, resulting in significant delays in engraftment and immune reconstitution, as well as an increased risk of graft failure and early transplantation-related mortality. Despite these limitations, the second decade of CBT was marked by improved outcomes, especially in adults, as better knowledge of cell dose requirements led to improved collection and the availability of units with higher cell doses. Better supportive care also contributed to these improved outcomes. Initial reports showed outcomes for CBT recipients on par with conventional HSCT recipients [3-5]. Finally, the advent of double CBT (dCBT) brought a significant reduction in the risk of graft failure, opening up the possibility of HSCT with CB for essentially all patients without a suitable donor [6]. Nonetheless, the use of dCBT did not produce faster neutrophil recovery or immune reconstitution, with cell dose remaining a major limitation. The advent of dCBT has, however, led to increased activity in the area of CB graft engineering, especially in the area of ex vivo expansion, with the double-unit platform allowing for manipulation of 1 unit and the ability to track both units in vivo. Ex vivo expansion of CB stem and progenitor cells to enhance engraftment is only one area of CB graft engineering currently under clinical investigation. As discussed below in more detail, the generation of immunotherapy from CB grafts is under active investigation both preclinically and now in the clinic as a means of overcoming the issues of delayed immune reconstitution in CBT recipients, with the generation of multivirus-specific cytotoxic T lymphocytes to treat viral infections. Relapse also remains a problem for all patients undergoing HSCT for hematologic malignancy. The ex vivo expansion of CB-derived T cells genetically modified to express CD19 or CD20 chimeric antigen receptors (CARs) to prevent relapse and the ex vivo generation of increased numbers of CB-derived NK cells as a means of better disease control are discussed below. This review focuses on these primary areas of graft engineering, but by no means represents an exhaustive list of the active research ongoing in the field of CB graft engineering. Other areas not covered in this review include the generation of regulatory T cells for GVHD prophylaxis, biological-based bioengineering approaches to enhance stem cell expansion, and preclinical research into the generation of CB-derived induced pluripotent stem cells. With continued advancement in the field, it is possible that a single CB unit could be manipulated based on an individual patient's greatest clinical need, with generation of specific cell types as clinically appropriate (Figure 1). Open in a separate window Figure 1 The potential of CB graft engineering.

1085P - First 100 Days Outcome of Autologous Non-Cryopreserved Peripheral Blood Stem Cell Transplants in Multiple Myeloma

ABSTRACT Background We report the outcome of autologous stem cell transplant (ASCT) in multiple myeloma (MM) after high dose melphalan with peripheral blood stem cell (PBSC) rescue without cryopreservation in terms of feasibility, safety and 100 day morbidity and mortality. Methods Between Sept 1994 and Feb 2012 a total of 81 patients (56 males, 25 females) were treated with non cryopreserved ASCT, with conditioning regimen of high dose melphalan 140-200 mg/m2 given on day-1. PBSC was collected after G-CSF mobilization with a mean number of leukapheresis of 1.5 (range 1-3) and was stored at 40C for 1-3 days (median = 2) before reinfusion on day 0. The median MNC was 3.0 x 108/kg (range 0.99 – 8.07) and CD34 dose was 2.34 x 106/kg (range 0.18 – 7.67). Results Median age was 50 years (range 22-65). The median time from diagnosis to transplant was 12.1 months (range 4.3 - 99.9). Prior to transplant, 67 patients (83%) had chemosensitive disease (CR, VGPR, PR) and 13(16%) had chemoresistant (stable, refractory or progressive) disease. Forty five (55%) patients had an ECOG PS of 0-1. The median score for hematopoietic cell transplant comorbidity index (HCT-CI) was 0 (range 0-6). The median time to neutrophil engraftment was 10 days (range 8-27) and platelet engraftment was 14 days (range 9-38). Febrile neutropenia occurred in 98.7% patients with a clinically defined focus observed in 14.8%, microbiologically documented infection in 27.1% and fever of unknown origin in 56.7% cases. Antibiotics were used for a median of 10 days (range 5-42). Total toxicity score (sum of toxicity grades for all organs as per Seattle criteria) ranged from 0-13 (median =2) and the median length of hospital stay (LOS) was 18 days (range 12-62). Day 100 mortality was 2.4% (n = 2). Disease status post transplant was CR in 14.8%, VGPR in 60.4% and PR in 11.1% with stable or refractory disease in 8.6%. LOS significantly correlated with age ≥ 50 yrs and HCT-CI of > 0 (p = 0.028 and 0.007 respectively) but not with ECOG PS (p = 0.28). Cumulative toxicity score had no significant correlation with either age, HCT-CI or PS. Conclusion ASCT in MM using non cryopreserved PBSC graft is safe and effective. It may be a prudent alternative with potential for wider applicability. Disclosure All authors have declared no conflicts of interest.

CD34+ cell content in unrelated allogeneic peripheral blood stem cell grafts transported internationally. Does the inter-laboratory variability affect comparability of graft quality data?

BackgroundIncreasing numbers of unrelated hematopoietic stem cell grafts are transported internationally and evaluated concurrently in different laboratories. The graft quality assessment using the CD34+ enumeration could be influenced by inter-laboratory variability. MethodsWe retrospectively analyzed the content of CD34+ cells in 154 consecutive collections being performed in different transplant centers during two periods (2003–2004, 2007–2010). All samples were tested twice in our own and partner laboratories. CD34+ percentage and absolute number were compared. ResultsThe percentage and the total CD34+ content correlated well in both observed periods (CD34+%: r=0.899 and r=0.922; CD34+×108/kg: r=0.966 and r=0.880; p<0.0001). Median CD34+ percentages obtained in our centre in comparison with other laboratories were 0.54% vs. 0.46% in 2003–2004 and 0.69% vs. 0.70% in 2007–2010 period. The degree of laboratory compliance was affected by the laboratory identity. CD34+ percentage reported by one laboratory and CD34+×108/kg reported by three from twelve laboratories lacked statistically significant correlation with our own data. ConclusionsThe study documented that results of CD34+ cell dose assessment of the same grafts reported by different transplant centers are comparable. The graft quality data and the CD34+ enumeration possess a limited level of inter-laboratory variability.

Infusion of hemolyzed red blood cells within peripheral blood stem cell grafts in patients with and without sickle cell disease

AbstractPeripheral blood stem cell (PBSC) infusions are associated with complications such as elevated blood pressure and decreased creatinine clearance. Patients with sickle cell disease experience similar manifestations, and some have postulated release of plasma-free hemoglobin with subsequent nitric oxide consumption as causative. We sought to evaluate whether the infusion of PBSC grafts containing lysed red blood cells (RBCs) leads to the toxicity observed in transplant subjects. We report a prospective cohort study of 60 subjects divided into 4 groups based on whether their infusions contained dimethyl sulfoxide (DMSO) and lysed RBCs, no DMSO and fresh RBCs, DMSO and no RBCs, or saline. Our primary end point, change in maximum blood pressure compared with baseline, was not significantly different among groups. Tricuspid regurgitant velocity and creatinine levels also did not differ significantly among groups. Our data do not support free hemoglobin as a significant contributor to toxicity associated with PBSC infusions. This study was registered at clinicaltrials.gov (NCT00631787).

Graft invariant natural killer T-cell dose predicts risk of acute graft-versus-host disease in allogeneic hematopoietic stem cell transplantation

AbstractInvariant natural killer T (iNKT) cells are powerful immunomodulatory cells that in mice regulate a variety of immune responses, including acute GVHD (aGVHD). However, their clinical relevance and in particular their role in clinical aGVHD are not known. We studied whether peripheral blood stem cell (PBSC) graft iNKT-cell dose affects on the occurrence of clinically significant grade II-IV aGVHD in patients (n = 57) undergoing sibling, HLA-identical allogeneic HSCT. In multivariate analysis, CD4− iNKT-cell dose was the only graft parameter to predict clinically significant aGVHD. The cumulative incidence of grade II-IV aGVHD in patients receiving CD4− iNKT-cell doses above and below the median were 24.2% and 71.4%, respectively (P = .0008); low CD4− iNKT-cell dose was associated with a relative risk of grade II-IV aGVHD of 4.27 (P = .0023; 95% CI, 1.68-10.85). Consistent with a role of iNKT cells in regulating aGVHD, in mixed lymphocyte reaction assays, CD4− iNKT cells effectively suppressed T-cell proliferation and IFN-γ secretion in a contact-dependent manner. In conclusion, higher doses of CD4− iNKT cells in PBSC grafts are associated with protection from aGVHD. This effect could be harnessed for prevention of aGVHD.

Clinically significant anti‐A1 in a presumed ABO‐identical hematopoietic stem cell transplant recipient: a case report

BACKGROUND: Subgroups of the blood group A (ABO) are generally not considered ABO incompatible for hematopoietic progenitor cell (HPC) transplant.CASE REPORT: A 54‐year‐old female presented for HPC transplantation for acute leukemia. No HLA‐matched donor was identified, so she received a peripheral blood stem cell graft from an HLA‐mismatched unrelated donor. On pretransplant testing, both the donor and the recipient typed as blood group A. On Day +67 after transplant, the recipient had a transfusion reaction consisting of an increase in temperature, rigors, and shaking chills during infusion of a unit of group A red blood cells (RBCs). A transfusion reaction workup revealed an ABO discrepancy with both anti‐A (1+) and anti‐B (3+) identified in the patient's serum as well as a positive direct antiglobulin test with monoclonal anti‐IgG antisera. Anti‐A1 were identified serologically and in an eluate. Hemolysis was clinically significant, requiring blood transfusion. No ABO typing discrepancies were found on pretransplant testing in either the recipient or the donor. DNA sequencing for blood group A subgroups performed after the transfusion reaction on blood collected before the transplant showed the donor to be type A1 and the recipient as A2. Unfortunately, the patient experienced graft failure requiring reconditioning and reinfusion of additional cells from the original HPC donor. On Day +94 after the second transplant, the patient died with severe acute gastrointestinal graft‐versus‐host disease.CONCLUSION: This report describes a blood group A2 patient who developed an anti‐A1 causing clinically significant hemolysis after HPC transplant from an A1 donor.

Haploidentical hematopoietic stem cell transplantation in hematologic malignancies with G-CSF mobilized bone marrow plus peripheral blood stem cells grafts without T cell depletion: a single center report of 29 cases

Haploidentical Hematopoietic stem cell transplantation (Haplo-HSCT) has provided an alternative option since virtually all patients have an immediately available donor. Here, we report the results of Haplo-HSCT with granulocyte-colony-stimulating factor (G-CSF) mobilized bone marrow grafts plus peripheral blood stem cells as the grafts without T-cell depletion. Twenty-nine patients with the mean age of 27.27 years (ranging from 15 to 51 years) were enrolled in this study, and 10 cases were in high risk status. The patients received myeloablative preconditioning with or without total body irradiation and acute graft-versus-host disease (GVHD) prophylaxis consisting of basiliximab, cyclosporine A, methotrexate, mycophenolate mofetil and a rabbit anti-thymocyte globulin. All the patients attained successful neutrophil and platelet recovery. The mean times for neutrophil and platelet recovery were 17.1 and 20.9 days, respectively. During the follow-up at a median time of 30.69 months (ranging from 3 to 76 months), nine patients developed aGVHD grade II–IV, including two developed grade III–IV GVHD after donor lymphocyte infusion. The incidence of cGVHD was 48.3%. 13 patients died within the first two years after transplantation, and the total disease-free survival rate longer than 2 years was 55.2%. These results suggest that G-CSF-primed bone marrow plus peripheral blood stem cell grafts are an appropriate stem cell source for Haplo-HSCT and large scale investigations are needed to confirm this protocol.

G-CSF stem cell mobilization in human donors induces polymorphonuclear and mononuclear myeloid-derived suppressor cells

The role of myeloid-derived suppressor cells (MDSC) is emerging in transplantation. An expansion of myeloid progenitor cells with suppressive capacity has been reported to occur as a bystander phenomenon in the course of allogeneic hematopoietic stem cell transplantation (allo-HSCT) protocols, particularly, in mice during bone marrow chimerism induction and in human stem cell donors during G-CSF-mobilization protocols. Hypothesizing that such 'regulatory myeloid cells' play a role in regulating post-transplant T-cell alloreactivity, we performed a phenotypical and functional characterization of these cells in peripheral blood stem cell grafts of G-CSF-treated donors. We demonstrate that expanding myeloid cells in the peripheral blood of G-CSF-mobilized donors comprise the typical phenotype of the mononuclear and polymorphonuclear MDSC-subtypes that were recently described in cancer patients, and that both MDSC-subsets have the capacity to regulate alloreactive T-cell responses in-vitro. This study provides the basis for investigating the clinical relevance of MDSC and MDSC-subtypes in human allo-HSCT.

Allogeneic Hematopoietic Cell Transplantation for Consolidation of Vgpr or Cr in Myeloma

Abstract 4581 Allogeneic hematopoietic cell transplantation (HCT) from HLA-identical siblings has been shown to prolong survival of patients with multiple myeloma in some studies. However, all published clinical trials of up front allogenic transplant for myeloma were conducted before thalidomide, lenalidomide and bortezomib became available; as such, less than 10% of the patients were in complete remission (CR) at time of transplantation. With contemporary therapy incorporating novel agents, more than 50% of patients achieve very good partial response (VGPR) or better (VGPR or CR). We summarize our experience with the safety and efficacy of allogeneic transplantation for patients achieving VGPR or better following induction therapy containing novel agent(s). Thirteen myeloma patients with first VGPR or CR received allogeneic HCT between July 2007 and January 2011. Median age at transplant was 45 years (range, 25 – 59), median time from initial therapy to transplant was 236 days (range, 122 – 410). Six patients (46%) have high-risk cytogenetics/FISH. Five patients received bortezomib plus lenalidomide induction therapy and eight patients received bortezomib-induction. Three patients (23%) underwent autologous HCT with melphalan plus bortezomib conditioning (melphalan 100 mg/m 2 for 2 days followed by bortezomib 1.3 mg/m 2 ) subsequent to induction therapies to achieve further cytoreduction prior to allogeneic HCT. Median number of prior therapies was 2 (range, 1–2). Disease status at the time of allogeneic HCT was stringent CR (n=5), CR (n=3), and VGPR (n=5). All patients received unmanipulated peripheral blood stem cell grafts from HLA-matched sibling donors (n=5) and HLA-matched unrelated donors (n=8). Six patients received fludarabine 30 mg/m 2 for 4 days and melphalan 70 mg/m 2 for 2 days followed by a single dose of bortezomib 1.3 mg/m 2 (Flu/Mel/Vel). Seven patients received fludarabine 40 mg/m 2 for 4 days and melphalan 70 mg/m 2 for 2 days (Flu/Mel). Graft-versus-host disease (GVHD) prophylaxis constitutes tacrolimus/methotrexate (n=5), tacrolimus/mycophenolate mofetil (n=4), and tacrolimus/sirolimus (n=4). All patients achieved neutrophil engraftment after a median of 17 days (range, 11 – 19), and all patients achieved platelet engraftment after a median of 17 days (range, 12 – 21). All patients established stable donor cell chimerism. Best responses after allogeneic HCT were sCR (n=10), CR (n=2) and VGPR (n=1). The cumulative incidence of grades 2–4 acute GVHD at day 100 was 57% (95% CI 0.30 – 1.00) with Flu/Mel conditioning and 33% (95% CI 0.11 – 1.00) for Flu/Mel/Vel conditioning, respectively (p=0.24). This observation suggests that a single dose of bortezomib 48 hours before HCT may prevent GVHD. One patient died of GVHD complications, 1 had disease progression and 11 remain alive, progression free with a median follow-up of one year (range 4 months to 4 years). The one year progression-free survival estimate is 90% (95%CI 0.71 – 1.00). These initial data indicate that allogenic transplant for myeloma in VGPR or CR is well tolerated. Longer follow-up is required to assess the efficacy of allogeneic HCT in the era of novel agents in preventing progression of the disease. Disclosures: Baz: Millenium: Research Funding, Speakers Bureau; Celgene: Research Funding. Alsina: Millennium: Consultancy, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity’s Board of Directors or advisory committees; Allergan: Research Funding.

Results of Phase II Clinical Trial MPD-RC 101: Allogeneic Hematopoietic Stem Cell Transplantation Conditioned with Fludarabine/Melphalan in Patients with Myelofibrosis

Abstract Abstract 1750 The Myeloproliferative Disorder-Research Consortium (MPD-RC) designed the first US prospective phase II study of allogeneic hematopoietic stem cell transplantation (HSCT) in patients with primary myelofibrosis (PMF) or MF secondary to essential thrombocythemia (ET-MF) or polycythemia vera (PV-MF). Between May 2007 and March 2011, 66 patients were entered into the MPD-RC 101 study. Thirty-two patients received an allogeneic HSCT from a related and 34 patients from an unrelated donor. In the two groups diagnoses were: PMF: 44%, 74%; ET-MF: 47%, 12% and PV-MF: 9%, 15%, respectively. A reduced intensity regimen with fludarabine/melphalan (FluMel) ± ATG was used. Of 66 patients, 63 were at intermediate/high risk according to Lille score system and 3 patients were at low risk but had thrombocytopenia. Recipients of related and unrelated HSCT were comparable with respect to age (median: 54 vs 55 years), gender (M/F 19/13 vs 19/15), Lille score intermediate (63% vs 68%) or high risk (28% vs 32%) and time from diagnosis to transplant (median, range: 16, 1–247 vs 20, 2–341 months). At the time of transplant, 66% and 82% of patients in the related and unrelated cohorts had splenomegaly and 19% and 15% had previous splenectomy. Jak-2 V617F mutation was present in 38% and 50% and an abnormal karyotype was detected in 56% and 59% of patients with known status, respectively. Bone marrow stem cells were utilized in 19% of related and 9% of unrelated transplants, while in the remaining cases patients received peripheral blood stem cell (PBSC) grafts. Donor compatibility was assessed by molecular typing for HLA A, B, C, DRB1 and DQB1 antigens; inclusion criteria allowed enrollment with maximum 1 antigen mismatched donor. Thirty of 32 transplants (94%) in the related cohort and 25/36 (74%) in the unrelated cohort were fully matched. In transplants from related donor, engraftment of neutrophils and platelets occurred in 31/32 patients, One patient in this group experienced a secondary graft failure. In contrast, among patients in the unrelated group only 26/34 (76%) patients engrafted and of these 4 had a secondary graft failure post transplant. Median time to neutrophils > 0.5 × 109/L and platelets >20 × 109/L engraftment was: day 22 and day 28 in the related, and day 18 and day 28 in the unrelated cohort, respectively. Acute GVHD grade II-IV was observed in 37% related (grade III-IV: 12%) and in 42% unrelated transplants (grade III-IV: 21%). Based on the International Working Group criteria, in patients who were followed for at least 6 months there were 7 CR, 8 PR, and 11 CI among the 28 patients in the related group, and 5 CR, 1 PR, and 5 CI among the 16 patients in the unrelated group. After a median follow-up for survivors of 24 months, 25 patients (78%) in the related group are alive, 6 patients (18%) died for causes related to transplant (GVHD n=3, cardiac toxicity n=1, renal failure n=1, secondary cancer n=1) and 1 (3%) for progression of disease. In the unrelated group, 15 patients (44%) are alive at 12 months follow-up for survivors, 18 patients (53%) died for causes related to transplant and 1 patient (3%) due to relapse. Median survival time has not been reached in the related transplant group and is 7 months in the unrelated group (hazard ratio 4.2, 95% CI: 1.7–10.1, p Disclosures: No relevant conflicts of interest to declare.

Marrow versus Blood-Derived Stem Cell Grafts for Allogeneic Transplantation from Unrelated Donors in Patients with Active Myeloid Leukemia or Myelodysplasia

Peripheral blood stem cells (PBSCs) are increasingly used as the graft source in allogeneic hematopoietic cell transplantation. We compared long-term outcome after unrelated donor transplantation of 85 consecutive patients with acute myelogenous leukemia or myelodysplastic syndrome regarding disease status (early disease [CR1, refractory anemia); n = 25 and advanced/active disease [>CR1, >refractory anemia]; n = 60) who were treated with conventional conditioning regimens followed by bone marrow (BM) or PBSC grafts. Graft-versus-host disease prophylaxis consisted mainly of cyclosporine A, short-course methotrexate, and anti-T-lymphocyte globulin. After a median follow-up of 118months (68-174), the 10-year event-free survival rate after peripheral blood stem cell transplantation (PBSCT) was 54.8% (95% confidence interval [CI], 39.7%-69.8%), and after bone marrow transplantation (BMT), it was 27.9% (14.5%-41.3%; P < .004). In the advanced/active disease group, the 10-year event-free survival rate after PBSCT was 50% (30.8%-69.2%), and after BMT, it was 23.5% (9.3%-37.8%; P < .007). Non relapse mortality was less after PBSCT than BMT (14.3% vs 30.2%), respectively. In multivariate Cox regression analysis, PBSCT showed a better overall survival (OS; hazard ratio [HR], 0.43; 95% CI, 0.23-0.79; P = .007) compared to BMT; unfavorable/unknown prognostic impact cytogenetic abnormalities were an adverse factor for all patients (HR, 2.202; 95% CI, 1.19-4.06; P = .011). In patients with advanced disease, the use of PBSCs showed a significant favorable outcome via multivariate analysis (HR, 0.49; 95% CI, 0.24-0.99; P = .046). Outcome of acute myelogenous leukemia/myelodysplastic syndrome after unrelated hematopoietic cell transplantation is adversely affected by cytogenetic abnormalities and state of remission at hematopoietic cell transplantation. PBSC as a graft source has a significant favorable influence on survival.

Association Between MDSCs and Acute Graft-Versus-Host Disease After Allogeneic Hematopoietic Stem Cell Transplantation,

Abstract 4069Myeloid derived suppressor cells (MDSCs) are a group of heterogeneous cells, derived from bone marrow progenitor cells and immature myeloid cells. In tumor development and progression, MDSCs play a role of immunosuppressive effect. Recently, researchers found that granulocyte colony-stimulating factor (G-CSF) could mobilize MDSCs from bone marrow (BM) to peripheral blood (PB), but there is unknown about the effect of G-CSF to MDSCs in the human body and the relationship between MDSCs and graft-verse-host disease (GVHD). So we investigated the association between MDSCs and acute graft-verse-host disease (aGVHD).The expression of MDSCs and adhesion molecules in the BM, PB and peripheral blood stem cell grafts in 30 related donors, were detected by flow cytometry before and after recombined human G-CSF (rhG-CSF) mobilization. The expression of arginase (ARG) and inducible nitric oxide synthase (iNOS) were detected by enzyme-linked immunosorbent assay. According to the median number of MDSCs in peripheral blood stem cell harvests (9.60×106/kg), 30 leukemia patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) were divided into two groups, high MDSCs group and low MDSCs group. The hematopoietic/immune reconstitution, incidence of aGVHD, relapse, and survival rate were compared between two groups.MDSCs could be detected in the blood and BM in healthy donors, the proportion in nuclear cells in the blood and BM was 0.30% ± 0.09% and 0.53% ± 0.16%, respectively. MDSCs in BM was higher than that in PB (P <0.001). After 5 days of rhG-CSF mobilization, the proportion in the blood and BM was 0.66% ± 0.28% and 0.72% ± 0.13%, respectively. The difference between proportion in the blood before and after mobilization was significant (P =0.017). Adhesion molecules on MDSCs surface after rhG-CSF mobilization were significant lower than that before rhG-CSF mobilization, both in blood and BM (P <0.001). The expression of ARG and iNOS after mobilization were significantly higher than that before mobilization (P<0.001), but not in BM (P =0.695, 0.073). There was a significant negative correlation between the number of transplanted MDSCs cells and the grading of aGVHD (correlation coefficient rs =0.445, P =0.014). The difference between the incidence of aGVHD in high MDSCs group and low MDSCs group (20.00% 315 vs 66.67% 1015, P =0.011), there was no significant difference between the hematopoietic/immune reconstitution, relapse rate (26.67% 415 vs 20.00% 315, P =0.671) and disease-free survival rate (46.7% ±14.2% vs 38.9%±15.8%, P =0.833) in two groups.In conclusion, in the human body, rhG-CSF could transfer more MDSCs from BM into the blood. RhG-CSF mobilization could increase the number of MDSCs in graft, which may be related to low incidence of aGVHD after allo-HSCT. The mechanism of rhG-CSF mobilized MDSCs to blood may be related to adhesion factor on MDSCs surface. The incidence of aGVHD in patients who accepted high MDSCs cells was lower; there was a significantly negative correlation between MDSCs transplant value and the grading of aGVHD. MDSCs cell infusion did not affect the function of immune reconstitution and the effect of graft versus leukemia. Disclosures:Liu:National Natural Science Foundation of China (No.30971300), Science and Technology Planning Project of Guangdong Province of China (No.2009A030200007): Research Funding.

Improved Clinical Outcomes of High Risk β Thalassemia Major Patients Under Going a HLA Matched Related Allogeneic Stem Cell Transplant with the Use of a Treosulphan Based Conditioning Regimen and Peripheral Blood Stem Cell Grafts

Abstract 1017▪▪This icon denotes a clinically relevant abstractAllogeneic stem cell transplant (SCT) remains the only curative option for patients with β thalassemia major (TM). However, the clinical outcome following SCT in patients with TM who belong to the Class III and the Class III high risk (HR) group remains poor. (Class III HR = age≥7 years and liver size≥5 cms: defined by us previously; BBMT 2007;13:889).From October, 1991 to June, 2011, 332 HLA matched related transplants for TM were done at our center. In an attempt to improve the clinical outcomes we used a Fludarabine (Flu) with intensity reduced Bu/Cy conditioning regimen, for a short period in 2006 and from August, 2009 a treosulphan based conditioning regimen (thiotepa: 8 mg/kg on day-6, treosulphan: 14gm/m2 for 3 days from day −5 to −3 and fludarabine 40mg/m2 for 4 days from day -5 to -2). We undertook a retrospective analysis to compare the impact of these alterations on the clinical outcome, especially in the high risk groups.A total of 178 (53.6%) Class III underwent SCT and 76 (42% of Class III) of these were Class III HR. Of the Class III patients, 135 received a conventional oral busulphan based conditioning regimen, 13 the Flu/Bu/Cy regimen and 30 the treosulphan based regimen (baseline characteristics of three groups summarized in Table 1). The treosulphan based regimen was associated with a significant reduction on the incidence of sinusoidal obstruction syndrome (SOS), TRM and rejections (table 1). The 2 year Kaplan-Meier estimate of EFS for these three groups was 59.6 ± 4.3, 23.1 ± 11.7 and 89.1 ± 6.0) respectively (P=0.000). Among those conditioned with a treosulphan based regimen DAH occurred in 4 and two of them (who also had features of SOS) succumbed to subsequent complications. With the treosulphan based regimen, initially bone marrow was the stem cell source (n=12) and this was associated with a delay in engraftment (median time to ANC>1000/mm3 was 19 days: range: 15–21), greater morbidity and a higher incidence of mixed chimerism on day 28 post transplant (50%) compared to PBSC (n=18, median time to ANC>1000/mm3= 15 days; range: 12–28, day 28 mixed chimerism in 12%). Use of PBSC was not associated with a significant increased risk of acute or chronic GVHD. It was noted that these favorable observations were retained in the Class III HR subset and the 2 year Kaplan-Meier estimate of EFS in this subset, with a treosulphan based conditioning regimen (n=19), was 89.5 ± 7.0% (Figure 1).In conclusion a treosulphan based conditioning regimen with a peripheral blood stem cell graft is well tolerated in high risk patients with TM and significantly improves the clinical outcome.Table 1:Baseline characteristics and clinical outcomes of Class III patients conditioned with different conditioning regimens.Busulphan based N (%)/ Mean ± SD/ Median(Range)Fludarabine based N (%)/ Mean ± SD/ Median(Range)Treosulphan based N (%)/ Mean ± SD/ Median(Range)P-valueN1351330Age9 (2–24)11 (4–14)11 (4–21)0.102Sex: M85 (63)8 (61.5)19 (63.3)0.994Class III HR*53 (39.3)4 (30.8)19 (63.3)0.036Live size4 (2–11)4 (3–7)5 (2–10)0.066F>M#49 (36.3)5 (38.5)7 (23.3)0.379Splenectomy30 (22.2)1 (7.7)7 (23.3)0.455HbsAg5 (3.7)000.441HCV28 (20.7)1 (7.7)4 (13.3)0.371Stem cell source$———0.000BM125 (92.6)13 (100)12 (40)GBM9 (6.7)——PBSC1 (0.7)—18 (60)CD34 dose6.4 (2.64–15.8)7.1 (2.80–12.7)11.4 (4.1–24.4)0.001ANC>0.5 × 109/Lt (days)16.88 ± 4.1419.12 ± 2.7516.03 ± 2.910.047Platelet>20 × 109/Lt (days)30 (10–137)32 (22–49)16.5 (9–44)0.000SOS@89 (65.9)4 (30.8)4 (13.8)0.000Treatment related mortality40 (31.7)5 (41.7)2 (6.7)0.012Rejections———0.034Primary graft failure4 (2.9)6 (46.2)1 (3.3)Secondary graft rejection12 (8.9)12 (15.4)0 (0)Ac GVHD55 (45.8)2 (20.0)11 (37.9)0.240Ch GVHD17 (18.1)03 (13)0.4122 yr KM estimate of EFS59.6 ± 4.323.1 ± 11.789.1 ± 6.00.0002 yr KM estimate of OS65.8 ± 4.253.8 ± 13.893.3 ± 4.60.028*HR high risk#F>M female donor to male recipient$Stem cell source. BM=bone marrow, GBM=G-CSF primed BM, PBSC=peripheral blood stem cells@SOS sinusoidal obstruction syndrome [Display omitted] Disclosures:No relevant conflicts of interest to declare.

T-Cell Depleted (TCD) Hematopoietic Stem Cell (HSC) Boosts From the Original Donor without Conditioning for Poor Graft Function (PGF) Following Allogeneic Hematopoietic Stem Cell Transplants (HSCT)

Abstract 1942▪▪This icon denotes a clinically relevant abstract BACKGROUND:Poor graft function without immune rejection, defined as persistent cytopenias with a hypocellular marrow and full donor chimerism, is a life-threatening complication after allogeneic HSCT. Treatment options include supportive therapy with transfusions and growth factors, vs administration of additional HSCs from the same donor without any conditioning (stem cell boost). The use of unmanipulated boosts increases the risk of development or worsening of GvHD by virtue of infusing mature T cells. The aim of this retrospective study was to evaluate the efficacy and safety of TCD boosts in patients with PGF.PATIENT AND METHODS: Between January 1992 and December 2007, 35 patients from a single center with PGF following either an unmanipulated (10) or a TCD (25) allogeneic HCST received a TCD HSC boost collected from the original donor. T cells were removed ex-vivo from marrow grafts with soybean lectin agglutinin and sheep red blood cells (sRBC) rosetting and from peripheral blood stem cell grafts by positive selection with a CD34 antibody (Isolex) followed by sRBC rosetting. HSC donors were matched related (21), mismatched related (5) and unrelated (9). Indication for first transplant included: aplastic anemia (2), non-Hodgkin's lymphoma (5) and myeloid malignancies (28). The preparative regimen was myeloablative for all recipients of unmanipulated grafts and for 22 of 25 recipients of TCD grafts. With the exception of one patient, the cell dose as measured by total nucleated cell dose/kg or CD34 cells/kg was adequate. Following the initial transplant, all patients had partial or complete recovery of blood counts and full donor chimerism documented by karyotype, FISH analysis or DNA polymorphism.The median time from first transplant to the diagnosis of PGF was 4.5 months (0.72-90.7). Etiologies of PGF included: viral infection and anti-virals (10), bacterial sepsis (3), Mycobacterial infection (4), low cell dose (1), GvHD 12, and idiopathic (5). None of the patients had evidence of relapse or progression of their underlying disease. All patients received a TCD boost from the original donor; with 21 patients receiving bone marrow and 14 receiving PB HSC. RESULTS:Seven patients died before day 21 post boost and were not evaluable for blood count improvement. Improvement (PLT>50,000/μL, ANC>500/μL) occurred in 20 of the 28 evaluable patients (71.4 %) at a median time of 3.2 months; 17 of them (60.7%) had a more substantial improvement (PLT ≥100,000/μL and ANC31000/μL) at a median of 8.81 months. TCD boost infusions were well tolerated with no significant adverse events. Also, no new onset GvHD occurred after TCD boosts; although two patients with preexisting GvHD flared. The median survival for all patients following TCD boosts was 21.47 months (range: 1.84–208.45). The 2-year and 5-year survivals were 48.6% and 37.1% respectively. The 2-year survival for patients who had improvement of their counts was 90% and for those who remained pancytopenic despite the boost was 18%. The 2-year survival according to etiology was 52.9% for the infection group, 50% for the idiopathic and low cell dose, and 33.3% for the GvHD group. Patients were also analyzed according to their medical condition prior to receiving the boost and were separated into four groups based on organ function (serum creatinine ≥ 2; total bilirubin ≥ 2; need for mechanical ventilation) and infection status. Group A: outpatient with no infection and no organ dysfunction (9); group B: hospitalized but afebrile with no infection or organ dysfunction (7); group C: febrile or documented infection but preserved organ function (8); group D: organ dysfunction with or without a concurrent infection (11). The 2-year survival for each group was 55.6%, 85.7%, 50%, and 9%, respectively. Patients with organ dysfunction with or without concurrent infection had the lowest survival. Causes of death included: GvHD (10), infection (5), relapse (4), organ failure (3), and poor graft function (1). CONCLUSION:Treatment of PGF with a TCD HSC boost from the original donor is safe and effective with minimal risk of GvHD. Medical status at the time of the boost infusion had a significant impact on outcome. A TCD boost should be considered early in the course of PGF as once complications of persistently low blood counts occur the potential for benefit sharply declines. Disclosures:Small:Pfizer, Inc: Equity Ownership, family member employed by Pfizer, Inc. Perales:Pfizer, Inc: Equity Ownership.

Allogeneic Hematopoietic Cell Transplantation for Consolidation of VGPR or CR In Myeloma

Abstract 4581Allogeneic hematopoietic cell transplantation (HCT) from HLA-identical siblings has been shown to prolong survival of patients with multiple myeloma in some studies. However, all published clinical trials of up front allogenic transplant for myeloma were conducted before thalidomide, lenalidomide and bortezomib became available; as such, less than 10% of the patients were in complete remission (CR) at time of transplantation. With contemporary therapy incorporating novel agents, more than 50% of patients achieve very good partial response (VGPR) or better (VGPR or CR). We summarize our experience with the safety and efficacy of allogeneic transplantation for patients achieving VGPR or better following induction therapy containing novel agent(s). Thirteen myeloma patients with first VGPR or CR received allogeneic HCT between July 2007 and January 2011. Median age at transplant was 45 years (range, 25 – 59), median time from initial therapy to transplant was 236 days (range, 122 – 410). Six patients (46%) have high-risk cytogenetics/FISH. Five patients received bortezomib plus lenalidomide induction therapy and eight patients received bortezomib-induction. Three patients (23%) underwent autologous HCT with melphalan plus bortezomib conditioning (melphalan 100 mg/m2 for 2 days followed by bortezomib 1.3 mg/m2) subsequent to induction therapies to achieve further cytoreduction prior to allogeneic HCT. Median number of prior therapies was 2 (range, 1–2). Disease status at the time of allogeneic HCT was stringent CR (n=5), CR (n=3), and VGPR (n=5). All patients received unmanipulated peripheral blood stem cell grafts from HLA-matched sibling donors (n=5) and HLA-matched unrelated donors (n=8). Six patients received fludarabine 30 mg/m2 for 4 days and melphalan 70 mg/m2 for 2 days followed by a single dose of bortezomib 1.3 mg/m2 (Flu/Mel/Vel). Seven patients received fludarabine 40 mg/m2 for 4 days and melphalan 70 mg/m2 for 2 days (Flu/Mel). Graft-versus-host disease (GVHD) prophylaxis constitutes tacrolimus/methotrexate (n=5), tacrolimus/mycophenolate mofetil (n=4), and tacrolimus/sirolimus (n=4). All patients achieved neutrophil engraftment after a median of 17 days (range, 11 – 19), and all patients achieved platelet engraftment after a median of 17 days (range, 12 – 21). All patients established stable donor cell chimerism. Best responses after allogeneic HCT were sCR (n=10), CR (n=2) and VGPR (n=1). The cumulative incidence of grades 2–4 acute GVHD at day 100 was 57% (95% CI 0.30 – 1.00) with Flu/Mel conditioning and 33% (95% CI 0.11 – 1.00) for Flu/Mel/Vel conditioning, respectively (p=0.24). This observation suggests that a single dose of bortezomib 48 hours before HCT may prevent GVHD. One patient died of GVHD complications, 1 had disease progression and 11 remain alive, progression free with a median follow-up of one year (range 4 months to 4 years). The one year progression-free survival estimate is 90% (95%CI 0.71 – 1.00). These initial data indicate that allogenic transplant for myeloma in VGPR or CR is well tolerated. Longer follow-up is required to assess the efficacy of allogeneic HCT in the era of novel agents in preventing progression of the disease. Disclosures:Baz: Millenium: Research Funding, Speakers Bureau; Celgene: Research Funding. Alsina:Millennium: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Allergan: Research Funding.

Whole Blood Donor Chimerism At Day 30 After Reduced Intensity Conditioned Allogeneic Stem-Cell Transplantation Predicts Disease Relapse, and Is Strongly Associated with Pretransplant Lymphodepletion

Abstract 1939 Background:RIC SCT relies heavily on graft-versus-tumor alloreactivity, and relapse remains a major barrier to a favorable outcome. Early prediction of relapse would allow early intervention such as donor lymphocyte infusions (DLI), but factors that predict relapse and methods for detection of minimal residual disease are often disease specific and not standardized. The level of donor-recipient chimerism has been associated with both graft rejection and relapse, but the optimal timing, desired level, and predictive value of chimerism testing in RIC SCT are unclear. Furthermore, the clinical utility of whole blood (WB) vs T-cell chimerism is not well defined, particularly after RIC SCT. Methods:We aimed to assess the predictive value of early WB and T-cell chimerism on the incidence of relapse in SCT pts receiving a uniform RIC regimen for hematologic malignancies. Between August 2006 and May 2011, 120 consecutive patients (pts) underwent allogeneic SCT following conditioning with fludarabine 120mg/m2 and busulfan i.v. 6.4 mg/kg. Pts were not treated with pre-emptive DLI, but could receive DLI for relapse. Hematopoietic chimerism was determined by DNA genotyping of short tandem repeats. Chimerism was determined on WB and then on enriched T-cells, obtained by selection using CD3-labeled magnetic beads. We conducted a cumulative incidence analysis of relapse, using day 30 as a landmark to determine the predictive properties of chimerism studies obtained at that time. Results:The 1-yr cumulative incidence of relapse in this cohort was 48.3 ± 4.7%, and the median time to relapse was 102 days (range 16–566 days), highlighting the importance of early monitoring. 68 pts were in remission and had evaluable chimerism data on day 30; importantly, the 1-year incidence of relapse was not different between pts who did and did not have day 30 chimerism measured (50.2 ± 6.5% vs. 42.9 ± 7.2%, P=0.45). Median follow up was 238 days (range 75–1420). Median age was 61 (range 21–76) and 56% were male. Underlying diseases were AML (24), MDS (13), NHL (10), myelofibrosis (6), CTCL (4), Hodgkin (3), myeloma (3), CLL (2), aplastic anemia (2), CML (1). Pts received a peripheral blood stem cell graft (67) or bone marrow (1), harvested from a matched related (30) or unrelated (38) donor. A single antigen mismatch was present in 6 cases. GVHD prophylaxis was tacrolimus (55) or cyclosporine (13) based.Median WB donor chimerism at day 30 was 96% (range 31–100%). A cumulative incidence analysis of relapse from day 30 revealed that day 30 WB chimerism had a significant association with relapse (HR 0.97, 95% CI [0.95–0.99], P=0.0011), reflecting a 3% decrease in risk of relapse for each 1% increase in chimerism. Risk of relapse according to different day 30 chimerism levels is displayed in figure 1. Using a day 30 chimerism cutoff of 95%, we found a significant association with incidence of relapse (HR 0.29, 95% CI [0.15–0.57), P=0.0003). Pts who were alive without relapse at the end of follow-up had a significantly higher chance of >= 95% day 30 WB chimerism compared to pts who relapsed (88.9% vs. 45.5%, P=0.002). In 38 pts with myeloid diseases, there was a significant association between day 30 WB chimerism and risk of relapse (HR 0.97, 95% CI [0.96–0.99], P=0.00065), while in 22 pts with lymphoid diseases, an association did not reach statistical significance (HR 0.93, 95% CI [0.84–1.00], P=0.09).Median T-cell chimerism was 70% in the 49 evaluable pts with these measurements (range 26–99%). T-cell chimerism on day 30 did not predict relapse (HR 1.0, 95% CI [0.98–1.02], P=0.95).We analyzed potential associations between day 30 WB chimerism and various transplant and patient characteristics. A higher chimerism level was significantly associated with lower day 0 lymphocyte count (P=0.004) and lower preconditioning lymphocyte count (P=0.01), but was not associated with recipient or donor age, cell doses, busulfan levels, disease type and donor type. The day 0 lymphocyte count was also a strong predictor of relapse (HR 6.87, 95% CI [6.56–7.04], P=0.00035). Conclusions:Whole blood and not T-cell chimerism at day 30 is predictive of relapse after RIC SCT. WB chimerism is strongly associated with lower lymphocyte counts before and after the conditioning regimen. These data highlight the importance of adequate lymphodepletion and can be useful in designing future trials testing pre-emptive interventions to prevent relapse after RIC SCT. [Display omitted] Disclosures:No relevant conflicts of interest to declare.