Haploidentical Allogeneic Hematopoietic Stem Cell Research Articles

Depletion of Alloreactive T Cells after Haploidentical HSCT: Comparison of Outcomes for Ex Vivo Versus In Vivo Treatment Strategies

Background: The use of haploidentical allogeneic hematopoietic stem cell transplantation (haplo-HSCT) has increased owing to therapeutic advances that have mitigated the main barriers such as high incidence of graft-versus-host disease (GVHD) and non-relapse mortality (NRM). This is primarily attributable to the elimination of alloreactive T cells in either the patient or the graft. Such T-cell depletion can be performed in vivo early after T-cell-replete haplo-HSCT using post-transplant cyclophosphamide (PTCy). Alternatively, T-cell-depleted haplo-HSCT can be supplemented with T-lymphocytes that are depleted ex vivo of their alloreactive component in the form of ATIR101 (Kiadis Pharma). Patient exposure to PTCy to eliminate donor alloreactive cells can be performed easily and at low cost but may cause patient toxicity and increase relapse rates, and it requires post-transplant immune suppression. Although ATIR101 requires cell manufacturing and is more expensive, it limits toxicity to the patient, enables haplo-HSCT without the use of immunosuppressants, and may reduce relapse rates. Both strategies are promising, but no attempt has yet been made to compare clinical results in similar patient populations to delineate key features of alloreactive T-cell depletion performed either ex vivo or in vivo.Methods: Data from published retrospective studies (single-site or registry data) were analyzed to assess clinical outcomes of haplo-HSCT plus PTCy. The 1-year outcomes from these studies were compared with results from a pooled analysis of 2 phase II clinical trials of a single dose of ATIR101 (N=37, all patients with AML/MDS/ALL [CR-AIR-007, CR-AIR-008]). Studies in which PTCy was used in patient populations with >50% AML/MDS/ALL were identified (Ciurea 2015, Piemontese 2017, Solomon 2012, Ciurea 2012, Devillier 2015, Di Stasi 2014, Esquirol 2016, Sugita 2015). The 1-year rates of relapse, relapse-related mortality (RRM), NRM, GVHD, and overall survival (OS) for the ATIR101 clinical trials were compared with the weighted average of these outcomes for the identified studies. OS is known to correlate with disease risk index (DRI; Armand 2014); therefore, publications reporting both OS and DRI (McCurdy 2017, Ciurea 2015, Devillier 2015, Sugita 2015) were identified to compare OS. Differences in DRI between PTCy and ATIR101 study populations were adjusted according to the relationship between DRI and OS. Finally, PTCy studies reporting GVHD-free and relapse-free survival (GRFS) were identified (Solh 2016, McCurdy 2017, Santoro 2017). There is a clinically relevant and statistically significant correlation between GRFS and DRI, so 1-year GRFS rates from the 2 studies reporting DRI status (Solh 2016, McCurdy 2017) were also normalized according to the DRI profile in the ATIR101 clinical trials to allow comparison.Results: The weighted average of PTCy (N=571) outcomes in populations with >50% AML/MDS/ALL vs ATIR101 patient outcomes were: 29% vs 8% for relapse; 18% vs 8% for RRM; 22% vs 33% for NRM; 5% vs 5% for acute GVHD grade III/IV; 24% vs 3% for chronic GVHD; and 60% vs 58% for OS. The OS in DRI-adjusted studies for PTCy (N=561) was similar to that in ATIR101 clinical trials (63% vs 58%, respectively). The GRFS-reporting studies included a total of 708 patients (Sohl 2016, N=128; McCurdy 2017, N=372; Santoro 2017, N=208); 1-year GRFS rates for PTCy in these studies were 33% (95% CI: 25-41), 45% (95% CI: 40-50), and 33% (average), respectively. In the 2 studies reporting DRI (N=500), the DRI profile was more favorable than in the ATIR101 studies and the 1-year GRFS rates normalized in line with the ATIR101 studies were reduced to 30% (Sohl 2016) and 40% (McCurdy 2017). In patients intended to receive a single dose of ATIR101 after haplo-HSCT, Kaplan-Meier estimate of 1-year GRFS was 53% (95% CI 39-72) (Table 1).Conclusion: This is not a head-to-head comparison, so data should be interpreted with caution. However, in these cross-study analyses, first insights into a potential advantage of ex vivo (ATIR101) over in vivo (PTCy) depletion of alloreactive T cells is suggested, including but not limited to rates of relapse, chronic GVHD, and GRFS. A large, phase III, randomized control trial is thus underway to assess the relative safety and efficacy of ATIR101 after T-cell-depleted haplo-HSCT versus PTCy after T-cell-replete haplo-HSCT (CR-AIR-009 HATCY; NCT02999854). [Display omitted] DisclosuresDevine:Kiadis Pharma: Consultancy. Mielke:Kiadis Pharma: Other: Travel grants, Research Funding. Tuk:Kiadis Pharma: Consultancy. Meewisse:Kiadis Pharma: Employment. Sandler:Kiadis Pharma: Employment. Roy:University of Montreal: Patents & Royalties: Author on patent; Kiadis Pharma: Other: Travel support; Hopital Maisonneuve Rosemont: Patents & Royalties: Author on patent.

Efficacy and Safety of a Single Dose of Donor Lymphocytes Depleted of Alloreactive T-Cells (ATIR101) Following T-Cell-Depleted Haploidentical HSCT: A Pooled Analysis of Two Phase II Studies

Background: An ex vivo photodepletion method has been developed to produce ATIR101 (Kiadis Pharma), a donor lymphocyte infusion (2.0 × 106 cells/kg) administered after haploidentical allogeneic hematopoietic stem cell transplantation (haplo-HSCT) to aid immune reconstitution. ATIR101 is depleted of alloreactive T-cells and early administration after T-cell-depleted haplo-HSCT has the potential to reduce serious complications resulting from delayed immune reconstitution, such as infections, malignant relapse, and severe graft-versus-host disease (GVHD) in the recipient. The safety and efficacy of a single dose of ATIR101 are presented here in a pooled analysis of two phase II clinical trials: CR-AIR-007 (NCT01794299) & CR-AIR-008 (NCT02500550).Methods: A pooled analysis of 37 adult patients who received haplo-HSCT. All but 3 patients have completed 1 year of follow-up (data cut-off: June 1, 2018). The study designs are aligned, with similar inclusion and exclusion criteria and baseline patient characteristics. Overall, 32 patients received a single dose of ATIR101; n=5 did not receive ATIR101 and discontinued after HSCT due to death (n=2), graft failure (n=1), and rejection of the ATIR101 batch (n=2). In the pooled cohort, n=24 had acute myeloid leukemia (65%), n=10 had acute lymphoblastic leukemia (27%), and n=3 had myelodysplastic syndromes (8%), with 57% of patients having an intermediate disease risk index (DRI) and 43% a high DRI. All patients underwent myeloablative conditioning followed by a CD34+ selected stem cell graft from a haploidentical family donor. ATIR101, prepared from the same donor, was given at a median of 28 days post HSCT as a single dose of 2.0 × 106 cells/kg, without the use of prophylactic immunosuppression. These data were compared with outcomes from a historic control group of 35 patients treated with a T-cell-depleted CD34+ selected haplo-HSCT without ATIR101 at overlapping participating hospitals in a prospectively planned registry study (CR-AIR-006, NCT02188290).Results: Thirty-six patients engrafted, with neutrophil engraftment at a median of 14 days (range 8-34) and platelet engraftment at a median of 12 days (range 7-35) post HSCT. Outcomes are shown in Table 1. In the pooled cohort, non-relapse mortality (NRM) was 33% and relapse-related mortality was 8%, compared with 66% and 15%, respectively, in the historic control group. The overall survival (OS) of patients was 58% in the pooled cohort (Figure 1A) and 20% in the historic control group. In the pooled cohort, total chronic GVHD was 3%, chronic severe GVHD was 0%, and acute GVHD grade III-IV was 5%, with 0% grade IV; in the historic control group, the results for total chronic GVHD, chronic severe GVHD, and acute GVHD grade III-IV were 11%, 9%, and 6%, respectively. The Kaplan-Meier curve for survival without grade III/IV acute GVHD, chronic GVHD requiring systemic treatment, or relapse (GRFS) showed significant separation for the pooled cohort versus the historic control group (P=0.01; Figure 1B); the GRFS rates for the two groups were 53% and 20%, respectively.Conclusion: OS was nearly threefold higher in the pooled cohort than in patients not receiving ATIR101 after haplo-HSCT in the historic control group. These outcomes were achieved without the need for concomitant high-dose immunosuppressive therapy. Disease relapse was limited and NRM in the pooled cohort was half that of the historic control group. Administration of a single dose of ATIR101 after a T-cell-depleted haplo-HSCT was well tolerated. The rate of GVHD is lower in the pooled cohort than the historic control group, suggesting that ATIR101 does not increase GVHD beyond the levels reported with a T-cell-depleted CD34+ selected HSCT alone. GRFS in the pooled cohort was >2.5-fold higher than the historic control group and also seems higher than GRFS rates previously reported for other studies using post-transplant cyclophosphamide (PTCy) after T-cell-replete HSCT (Solh 2017, McCurdy 2017). To further investigate the therapeutic potential of ATIR101, a large, phase III, randomized control trial is currently underway to assess the relative safety and efficacy of ATIR101 after T-cell-depleted haplo-HSCT, versus PTCy after T-cell-replete haplo-HSCT (CR-AIR-009 HATCY; NCT02999854). [Display omitted] DisclosuresRoy:University of Montreal: Patents & Royalties: Author on patent; Kiadis Pharma: Other: Travel support; Hopital Maisonneuve Rosemont: Patents & Royalties: Author on patent. Beguin:Kiadis Pharma: Consultancy. Selleslag:Kiadis Pharma: Other: Financial support for study-related issues. Wagner:Medac: Other: Travel grant. Bonig:Kiadis Pharma: Consultancy. Mielke:Kiadis Pharma: Other: Travel grants, Research Funding.

Impact of cyclosporine‐A concentration in T‐cell replete haploidentical allogeneic stem cell transplantation

This paper aims to study whether cyclosporine-A (CSA) levels have an impact on the clinical outcome of patients with T-cell replete haploidentical allogeneic hematopoietic stem cell transplantation (allo-HSCT). We analyzed 140 consecutive patients who had been given T-cell replete haploidentical allo-HSCT in our institute to assess the effect of CSA concentration in the early stages of allo-HSCT on clinical outcomes, such as hematopoietic recovery, acute graft vs host disease (aGVHD), infection, disease-free survival (DFS), and overall survival (OS). The median concentrations of CSA in the blood in the 1st, 2nd, 3rd, and 4th week after allo-HSCT were 218, 235, 263, and 270ng/mL, respectively. Additionally, 46%, 40%, 27%, and 18% of the patients had CSA blood levels below 200ng/mL during those weeks. In total, 39 patients developed aGVHD (grade II-IV), for a cumulative incidence of 27.8%, at a median of 32days. Patients having a low CSA concentration (below 200ng/mL) in the 3rd week had a higher cumulative incidence of grade II-IV aGVHD (P=.02). In addition, multivariate logistic regression analysis showed that low CSA concentration (below 200ng/mL) in the 3rd week was an independent risk factor of grade II-IV aGVHD (P=.02; odds ratio=2.66; 95% CI, 1.15-6.17). However, CSA levels during the first 4weeks did not have a significant impact on the patients' hematopoietic recovery, infection, DFS, and OS. Our data indicated that adequate management of CSA levels during the peri-engraftment period might improve clinical outcomes for those with T-cell replete haploidentical allo-HSCT.

Haploidentical allogeneic hematopoietic stem cell transplantation in patients with high-risk soft tissue sarcomas: results of a single-center prospective trial.

Haploidentical allogeneic hematopoietic stem cell transplantation in patients with high-risk soft tissue sarcomas: results of a single-center prospective trial.

Haploidentical hematopoietic SCT using helical tomotherapy for total-body irradiation and targeted dose boost in patients with high-risk/refractory acute lymphoblastic leukemia.

A novel conditioning regimen using helical tomotherapy (HT) was developed to deliver 10 Gy for total body irradiation (TBI) and simultaneously augment dose to 12 Gy for targeted dose boost to total marrow, central nervous system leukemia, and extramedullary disease sites in patients with high-risk or relapsed/refractory acute lymphoblastic leukemia (ALL) receiving haploidentical allogeneic hematopoietic stem cell transplantation (allo-HSCT). Fourteen patients were included, eight of these patients were in first complete remission (CR1), one was in CR2, one had a partial response and four patients had refractory disease at transplantation. The median delivered average dose was 11.395 Gy (range 10.06-12.17). The median planning target volume D95 was 8.2 Gy (range 7.52-9.01). The median delivered dose to skeleton bone with active bone marrow sites was 12.685 Gy (range 11.12-13.52). The results of this trial suggest that using HT TBI confers satisfactory immunosuppression and excellent eradication of malignant cells in patients with high-risk ALL undergoing allo-HSCT, especially in those with refractory ALL. After a median follow-up of 14.6 months (range 4-28), four patients experienced non-relapse mortality, ten patients are alive in durable CR including remission of extramedullary leukemic infiltration. One-year overall survival and disease-free survival rates post-transplantation were both 70.7%.

Haploidentical allogeneic hematopoietic stem cell transplantation compared to matched unrelated transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia

To investigate the effect of haploidentical allogeneic hematopoietic stem cell transplantation (Haplo-HCT) in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL), the outcome of 58 patients with Ph+ ALL who received Haplo-HCT (n=42) or matched unrelated donor transplantation (MUD-HCT) (n=16) during the same period were analyzed retrospectively. All patients received a tyrosine kinase inhibitor (TKI)-based regimen before transplantation, and TKI was resumed primarily after transplantation. At the 3-year follow-up, the overall survival (OS), leukemia-free survival (LFS), the cumulative incidence of relapse (CIR), and non-relapse mortality (NRM) rates in Haplo-HCT group were 69.1, 64.3, 19.0, and 14.3%, respectively, without significant differences from that of MUD-HCT. Haplo-HCT was not related to higher incidences of severe acute graft-versus-host disease (GvHD) (17.6±5.2% vs. 20.0±10.0%, P=0.603) or chronic GvHD (19.5±7.1% vs. 13.3±8.6%, P=0.637) as compared to MUD-HCT. Multivariate analysis showed that chronic GvHD was associated with lower relapse rate in Haplo-HCT group. Haplo-HCT is a promising choice for improving the long-term survival in Ph+ ALL patients.

A Rare Complication Developing After Hematopoietic Stem Cell Transplantation: Wernicke's Encephalopathy.

Thiamine is a water-soluble vitamin. Thiamine deficiency can present as a central nervous system disorder known as Wernicke’s encephalopathy, which classically manifests as confusion, ataxia, and ophthalmoplegia. Wernicke’s encephalopathy has rarely been reported following hematopoietic stem cell transplantation. Herein, we report Wernicke’s encephalopathy in a patient with acute myeloid leukemia who had been receiving prolonged total parenteral nutrition after haploidentical allogeneic hematopoietic stem cell transplantation. To the best of our knowledge, this is the first case reported from Turkey in the literature.

Haploidentical, unmanipulated G-CSF-primed peripheral blood stem cell transplantation for high-risk hematologic malignancies: an update.

Emerging data demonstrate promising results of related haploidentical allogeneic hematopoietic stem cell transplantation (haplo-HCT) for the treatment of hematologic malignancies. Data about G-CSF primed PBSC as reliable source of graft with myeloablative conditioning are lacking. We updated the outcomes in 130 adult patients with high-risk hematologic malignancies who received haplo-PBSC transplantation consecutively under busulfan-based conditioning. PBSC were freshly isolated and infused without ex vivo T-cell depletion into the recipients. Myeloid recovery was achieved in 99.2% patients with full donor chimerism. The cumulative incidence of acute grade 3-4 GvHD, overall and extensive chronic GvHD was 14.9%, 38.6% and 16.5%, respectively. The 3-year non-relapse mortality rate was 24.1%. Non-remission prior to transplant was associated with higher incidence of relapse (P=0.006), inferior overall survival (P=0.017) and leukemia-free survival (P=0.024). These data suggest that PBSC is a reliable graft source in haploidentical, unmanipulated transplant settings under myeloablative conditioning in patients with high-risk hematologic malignancies.

The current status and development of haploidentical allogeneic hematopoietic stem cell transplantation for severe aplastic anemia

The current status and development of haploidentical allogeneic hematopoietic stem cell transplantation for severe aplastic anemia

Effect of the microtransplantation of allogeneic hematopoietic stem cells as maintenance therapy for elderly patients with acute leukemia.

The incidence of acute myeloid leukemia (AML) increases with age. Elderly patients with AML are less tolerant to high-intensity consolidation therapy than younger patients, with significantly worse prognoses. Induction and consolidation therapy combined with allogeneic hematopoietic stem cell microtransplantation may improve the prognosis of elderly patients with AML. The present study reports the effect of maintenance therapy with low-dose chemotherapy treatment combined with microtransplantation in elderly patients with AML following consolidation. Between January 2011 and April 2014, three elderly patients (>55 years old), including one 58-year-old patient with acute mixed lineage leukemia (AMLL) and two patients with AML aged 59 years and 62 years, underwent microtransplantation maintenance therapy. Following a complete response to induction chemotherapy and consolidation chemotherapy with two to four cycles of medium dose Ara-c (auto transplantation was performed in the patient with AMLL), maintenance therapy was performed using low-dose Ara-c combined with human leukocyte antigen haploidentical allogeneic hematopoietic stem cell microtransplantation, which was repeated every 3 to 6 months. The patients were followed up for 27, 20 and 16 months, respectively, and all three patients achieved disease-free survival. The bone marrow Wilms' tumor suppression gene (WT1) level of the case with AMLL was dynamically monitored. The results showed that the WT1 level was abnormally high prior to microtransplantation and gradually declined to normal levels subsequent to the process. None of the patients suffered from graft versus host disease during the microtransplantation process. In conclusion, microtransplantation maintenance therapy following consolidation therapy is feasible in elderly patients with AML, and is expected to be able to further remove residual lesions and improve treatment efficacy. A large-scale clinical trial is required to confirm the effect of maintenance therapy in elderly patients with AML.

Efficacy analysis of haploidentical allogeneic hematopoietic stem cell transplantation in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia

This study was aimed to explore the effect and feasibility of related haploidentical allogeneic hematopoietic stem cell transplantation (hi-HSCT) used in the treatment of patients with Ph⁺ ALL. A total of 22 patients with Ph⁺ ALL received related hi-HSCT from March 2008 to August 2013. The clinical data of all cases were retrospectively analyzed.There were 15 cases of CR1, 3 cases of CR2, 1 case of CR3 and 3 cases of relapse. The bone marrow and peripheral blood stem cells of related haplotype donors were used for transplantation. All patients were subjected to pretreatment consisting of cytarabine, busulfan (Bu), cyclophosphamide and tota1 body irradiation (TBI), etc. GVHD was prevented by combining variety of immunosuppressants including CsA, MTX, MMF and ATG, etc. The results showed that all of 22 patients acquired hematopoietic reconstitution, and the median time of granulocytes exceeding 0.5 × 10⁹/L and platelets exceeding 20 × 10⁹/L which were transplanted by donors were 13 days and 23 days respectively. The mean follow-up period was 13 months. Ten patients had experience of aGVHD, and 8 patients had experience of cGVHD. Two patients died of infection, 3 died of GVHD and 3 died of relapse,and the rest patients were alive in disease-free situation at lase follow-up. The 2-year disease-free surviva1 rate was 57%. It is concluded that related hi-HSCT can prolong disease-free survival of Ph(+)ALL patients and even cure.

Retrospective analysis of therapeutic efficacy of haploidentical allogeneic hematopoietic stem cell transplantation for severe aplastic anemia

This study was purposed to investigate the therapeutic efficacy of haploidentical allogeneic hemopoietic stem cell transplantation (allo-HSCT) for severe aplastic anemia (SAA), and evaluate the safety of this treatment by retrospective analysis. A total of 21 patients with SAA (13 cases of SAA-I, 8 cases of SAA-II) were treated with haploidentical allo-HSCT. Donors were the relatives of the patients (12 were the parents, 9 were the siblings). The conditioning regimen contained cyclophosphamide, fludarabine and antithymocyte globulin. Methylaminopterin, mycophenolate mofetil and cyclosporin A were used for preventing graft versus host disease (GVHD). The chimerism rate was monitored periodically after successful graft. The long survival rate, incidence and severity of complication, such as GVHD, infection, and so on were analyzed. The results showed that 15 out of 21 patients were survived for 16 (3-46) months, survival rate was 71.4%. Graft tailure happened in one case who died of mycetes septicemia at 43 days after allo-HSCT. Two patients died of pulmonary infection at 6 days and 10 days respectively after transplantation. Rejection happened in one case at 3 months who died of pulmonary infection at 17 days after the second transplantation with the same donor. Two patients died of IV grade intestinal GVHD at 35 days and 52 days. GVHD occurred in 14 of 21 patients, the accumulative incidence was 66.7%, 5 cases of them were severe. It is concluded that the therapeutic efficacy of haploidentical allo-HSCT is effective for SAA and with slighter complications.

Mesenchymal Stem Cells in Grafts Failed to Engraft in the Bone Marrow Microenvironment of a Leukemia Patient Post HLA-match and Haplo-Identical Allogeneic Hematopoietic Stem cell Transplantations

Mesenchymal Stem Cells in Grafts Failed to Engraft in the Bone Marrow Microenvironment of a Leukemia Patient Post HLA-match and Haplo-Identical Allogeneic Hematopoietic Stem cell Transplantations

Long-Term Follow-up of Allogeneic Hematopoietic Stem Cell Transplantation for Patients with Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia: Impact of Tyrosine Kinase Inhibitors on Treatment Outcomes

The introduction of tyrosine kinase inhibitors (TKI) has revolutionized therapy for patients with acute lymphoblastic leukemia (ALL) who have the Philadelphia (Ph) chromosome. A retrospective analysis was conducted on 102 adults and 11 children who received a first-matched related (n = 60), matched unrelated (n = 40), mismatched cord blood (n = 12), or haploidentical (n = 1) allogeneic hematopoietic stem cell transplantation (HSCT) for Ph-positive (Ph+) ALL in first complete remission (n = 71), second complete remission (n = 11), or with active disease (n = 31) between 1990 and 2009. Sixty-seven patients received TKI with upfront ALL therapy, and 32 patients received TKI maintenance following HSCT. With median follow-up of 5 years among survivors (range: 1.1-20.4 years), overall survival (OS) was significantly better for patients transplanted in first remission compared with HSCT in advanced disease: 43% versus 16%, P = .002. Disease stage and age at time of HSCT, the development of acute graft-versus-host disease (aGVHD), and decade of HSCT were found to significantly impact OS, progression-free survival (PFS), and nonrelapse mortality (NRM) in multivariate analyses. Allogeneic HSCT provides durable remission for patients with Ph+ ALL in first remission. Neither TKI use pre- nor post-HSCT were found to significantly impact transplant outcomes in univariate and multivariate analyses.

135: A Two Step Approach to Haploidentical Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) for High Risk Patients with Hematologic Disorders

Post transplant cyclophosphamide (CTX) has been utilized to induce donor host tolerance in allogeneic HSCT. While promising, the long term risk of MDS and AML from exposure of the graft to CTX is unknown, and the optimal T cell dose to deliver using this approach remains undefined. To address these issues, 12 high-risk patients underwent haploidentical HSCT from related donors for disorders of hematopoiesis using a two step approach. Nine of 12 (75%) patients had evidence of disease at the time of HSCT.

A Two Step Approach to Haploidentical Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) for High Risk Patients with Hematologic Disorders.

Post transplant cyclophosphamide (CTX) has been utilized to induce donor host tolerance in allogeneic HSCT. While promising, the long term risk of MDS and AML from exposure of the graft to CTX is unknown and the optimal T cell dose to deliver using this approach remains undefined. To address these issues, nine high-risk patients, median age 55 (range 19–73) underwent haploidentical HSCT from related donors for various hematopoietic disorders using a two step approach. Seven of 9 (77%) patients had evidence of disease at the time of HSCT. In the GVH direction, 7 of 9 were 4/8 matches with their donors at HLA-A, B, C and DRB1; the other 2 patients were 5 /8 and 6 /8 matches. Seven of the 9 patients were given a myeloablative conditioning regimen of TBI (1.5 Gy) BID on days −9 through −6. Two received a nonmyeloablative conditioning regimen of fludarabine and ARA-C on days-11 through −8 and one 2 Gy fraction of TBI on day −6. The patients received 2x108/kg of their donor's CD3+ lymphocytes after completion of TBI on day −6, followed by rest days on day −5 and −4. On days −3 and −2, CTX was given at a dose of 60 mg/kg/day for the purpose of tolerization of the donor lymphocytes. On day 0, donor CD 34+ cells were infused. When possible, the number of non-tolerized T-cells in the CD 34+ product was limited to ≤5x104/kg. Tacrolimus and CellCept were used as GVHD prophylaxis. All of the patients developed fevers between DLI and CTX, with some patients also developing mild diarrhea and a rash, which in one case was biopsy-positive for GVHD. All patients engrafted. One patient developed grade III GVHD, two had grade II GVHD, and the rest had grade 0 or I GVHD. GVHD was easily controlled with corticosteroids which could be rapidly tapered in all but one patient. Four patients have died, two of relapsed disease (d+67, d+91) and two of infectious complications (d+101, d+42). An additional patient is alive, but with evidence of relapsed disease at d + 42. Four patients are well and in CR at days +250, +173, +144, and +118 days post HSCT. Three of the 4 have CD3/CD4 counts of greater than 170 cells/ml. This 2 step transplant procedure promotes the establishment of donor-recipient tolerance by in vivo CTX exposure, but avoids any effects of G-CSF on donor lymphocytes, allows delivery of a precise dose of T cells to all patients, and eliminates CTX exposure of the hematopoietic precursors. Patients who lack matched-sibling donors can be successfully transplanted on this protocol with little significant GVHD. Infection and relapse remain problems, but likely can be reduced through transplantation of patients earlier in their disease course.Patient DataAgeDiseaseTransplant TypeDLI Dose/kg x10e8CD 34 Dose/kg x10e6T Cells/kg in CD34 Product x10e4GVHD GradeOutcome19AML - PIFAblat2.01.40.260Died-Relapse55CML & AML - PIFAblat2.03.65.00NED26ALL - CR2Ablat2.02.26.9IINED44AML - CR2Ablat1.83.84.4IINED32SAAAblat2.01.70.13IIIDied-Infection59AML - Resist Relapse 1Ablat2.04.10.390Died-Relapse60Biph Leuk - Resist Relapse 1Ablat2.02.70.82IDied-Infection67AML - PIFNon-Ablat2.04.34.5IINED73AML - PIFNon-Ablat2.04.40.0590Alive-Relapsed