Donor Stem Cell Infusion Research Articles

Efficacy and safety analysis of umbilical cord blood combined with haploid hematopoietic stem cell transplantation in the treatment of malignant hematological malignancies

Objective: To investigate the efficacy and safety of umbilical cord blood combined with haploid HSCT (haplo-cord HSCT) in the treatment of hematological malignancies. Methods: The data of 82 patients with hematologic malignancies who received haplo-cord HSCT from January 2017 to June 2021 in the Affiliated Cancer Hospital of Zhengzhou University were retrospectively analyzed. There were 52 male and 30 female patients, aged [M(Q1, Q3)] 29 (20, 41) years. All patients received myeloablative preconditioning regimen. The day of the donor stem cell infusion was recorded as day 0 (0 d), the day before the infusion was recorded as day-1 (-1 d), and the day after the infusion was recorded as day+1 (+1 d), and so on. Eighty-two patients received transfusion of peripheral blood and/or bone marrow stem cells from unrelated cord blood and haplotype donors after the myeloablative preconditioning regimen. The graft-versus-host disease (GVHD) prophylaxis regimen was 8 mg/kg ATG combined with cyclosporine, morte-macrolide, and methotrexate. Patients were evaluated for implantation and the occurrence of transplant-related complications such as GVHD, infection, hemorrhagic cystitis, and long-term patient survival. Results: The time of neutrophil engraftment [M(Q1, Q3)] was 13 (11, 15) days and 15 (13, 21) days for platelet. The 30-day cumulative incidence of neutrophil engraftment was 98.8% (81/82) and 100-day cumulative incidence of platelet engraftment was 92.7% (76/82). The cumulative incidence of acute graft-versus-host disease (aGVHD) in degree Ⅱ-Ⅳ and Ⅲ-Ⅳ was 24.4% (20/82) and 6.1% (5/82), respectively. The cumulative incidence of chronic GVHD in+18 months was 13.5% (11/82). The follow-up time [M(Q1, Q3)] was 26 (13, 41) months, and the overall survival (OS) rate, event-free survival (EFS) rate, cumulative recurrence rate (CIR) and non-recurrence mortality (NRM) rate at 3 years after transplantation were 70.5% (95%CI: 59.7%-81.3%), 66.1% (95%CI: 56.1%-76.1%), 6.3% (95%CI: 5.7%-26.9%) and 20.8% (95%CI: 12.0%-29.6%), respectively. The cumulative incidence of cytomegalovirus and EBV reactivation was 37.8% (31/82) and 14.6% (12/82), respectively. The cumulative incidence of hemorrhagic cystitis was 32.9% (27/82). Conclusion: The efficacy of haplo-cord HSCT in the treatment of hematologic malignancies is reliable, with rapid hematopoietic reconstitution, low incidence of GVHD and virus reactivation.

Maintenance therapy following CD19 CAR-T treatment for relapsed B-cell acute lymphoblastic leukemia after allogeneic hematopoietic stem cell transplantation

目的探讨异基因造血干细胞移植后复发急性B淋巴细胞白血病（B-ALL）CD19 CAR-T细胞治疗缓解后的维持治疗，观察单独输注供者造血干细胞和供者T淋巴细胞对CD19 CAR-T细胞扩增的影响。方法1例难治B-ALL患者，CD19 CAR-T（鼠源，克隆号：FMC63）细胞治疗后桥接同胞全相合异基因造血干细胞移植，后再次复发。接受CD19 CAR-T（可变区人源化的FMC63）细胞治疗再次缓解，缓解后先后接受单独输注供者造血干细胞、供者T淋巴细胞的维持治疗，期间监测患者细胞因子水平、CD19 CAR-T细胞比例、CD19 CAR的DNA表达变化，观察骨髓白血病细胞比例及供者嵌合情况。另外，通过制备小鼠CD19 CAR-T（FMC63）细胞，并将CAR-T细胞注射至同窝小鼠体内，14 d后，再次注射同窝小鼠的B淋巴细胞，在此过程中观察CAR-T细胞、B淋巴细胞比例以及CD19 CAR的DNA表达，以此来模拟临床治疗过程。结果①患者输注人源化CD19 CAR-T细胞后第14天，疗效评估达完全缓解（CR），供者嵌合率为99.76%，细胞因子释放综合征1级。②人源化CD19 CAR-T细胞治疗缓解后，单独输注供者造血干细胞维持治疗，输注后第24天出现移植物抗宿主病（GVHD），患者GVHD期间伴有外周血CD19 CAR-T细胞比例及CD19 CAR DNA水平的升高，并随GVHD缓解下降。过程中患者维持CR且供者嵌合率为99.69%。③随后单独输注供者T淋巴细胞维持治疗，回输后第12天患者出现GVHD，而患者外周血CD19 CAR-T细胞比例及CD19 CAR的DNA水平并未出现再次升高。过程中患者维持CR且供者嵌合率为99.87%。④C57小鼠体内试验证实，CAR-T细胞输注后小鼠体内CAR-T细胞扩增及DNA表达上调，同时CD19+ B淋巴细胞耗竭。之后输注CD19+ B淋巴细胞，CD19 CAR-T细胞扩增和CD19 CAR的DNA表达再度上调。结论供者造血干细胞、供者T淋巴细胞的单独输注，可作为异基因造血干细胞移植后复发B-ALL接受CD19 CAR-T治疗缓解后的维持治疗手段，且输注供者造血干细胞诱发GVHD同时出现CD19 CAR-T细胞和CD19 CAR的DNA表达上调，有可能进一步清除残留灶。

Combination treatment of rituximab and donor platelets infusion to reduce donor-specific anti-HLA antibodies for stem cells engraftment in haploidentical transplantation.

BackgroundDonor‐specific anti‐human leukocyte antigen (HLA) antibodies (DSAs) in recipients is a risk factor for donor stem cell graft failure in haploidentical hematopoietic stem cell transplantation (haplo‐HSCT), and the treatment to reduce the levels of DSAs is not unanimous. This study was to analysis the role of DSAs for stem cell engraftment and to discuss the effective treatment to reduce DSAs in haplo‐HSCT.MethodsWe retrospectively evaluated the levels of DSAs and the effect of the combination treatment of rituximab and donor platelets (PLTs) for donor stem cell engraftment in haplo‐HSCT patients from June 2016 to March 2018 at our center.ResultsNine patients (11.5%) out of the total 78 patients were DSAs‐positive and multivariate analysis revealed DSAs was the only factor that affected engraftment. Seven out of the 9 DSAs (+) patients received therapy: Four had antibodies against donor HLA class I (HLA‐I) antigens and were administered two therapeutic amounts of donor apheresis platelets (platelet count approximately 3‐5 × 1011) before donor stem cell infusion and the other three patients received a combination therapy of donor apheresis platelets and rituximab due to the antibodies against both donor HLA‐I antigens and HLA class II (HLA‐II) antigens. All the seven patients achieved donor stem cell engraftment successfully, and the DSAs levels decreased rapidly after transplantation.ConclusionsDSAs is an important factor affecting engraftment in haplo‐HSCT. Donor platelet transfusion is one simple and effective treatment for HLA‐I DSAs, and a combination therapy should be administered if patients have both HLA‐I and HLA‐II antibodies.

Clinical analysis of sub-standard dose of donor stem cell infusion mobilized by granulocyte colony-stimulating factor in treatment of relapsed acute leukemia after allogenic hematopoietic stem cell transplantation

Objective To investigate the clinical effect and prognosis of sub-standard dose of donor stem cell infusion(DSI) mobilized by granulocyte colony-stimu1ating factor(G-CSF) in patients with relapsed acute leukemia (AL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods From January 2010 to April 2017, a total of 17 patients with relapsed AL after allo-HSCT in Department of Hematology, the First Affiliated Hospital of Xi′an Jiaotong University were included in the study. They were divided into DSI combined chemotherapy group (n=7) and chemotherapy alone group (n=10) according to different treatment after relapse. The basic clinical data of patients with relapsed AL after allo-HSCT were collected by retrospective analysis. The infusion dose of DSI, treatment results, adverse reactions and survival outcomes were observed in both groups. Kaplan-Meier method was used to draw the overall survival (OS) and survival after first relapse (SAR) curves of two groups. The OS and SAR rate were compared by Log-rank test between two groups. This study protocol was approved by the ethics committee of the First Affiliated Hospital of Xi′an Jiaotong University (Approoal No. XJTU1AF2010LSL-020). Informed consents were obtained from all patients before treatment. Results ① The median age of patients in DSI combined chemotherapy group was 28 years (11-49 years), 3 cases were positive in fusion gene, and 6 cases were achieved complete remission(CR)1 before transplantation, none of them had graft versus host disease(GVHD). The median age of patients in chemotherapy group was 22 years (15-37 years). The fusion gene was positive in 4 cases, and 2 cases had GVHD. ② In DSI combined chemotherapy group, 5 patients received single DSI treatment after conventional chemotherapy, and 2 patients received DSI treatment in every two weeks. Three patients (3 / 7) achieved CR. There were 4 patients with grade Ⅰ ~Ⅱ aGVHD of skin and liver, 3 patients with grade Ⅳ myelosuppression and pneumonia. Up to the end of follow-up, 1 patient survived and 6 died in DSI combined chemotherapy group. ③In the chemotherapy group, 3 patients (3 / 10) achieved CR after treatment. Up to the end of follow-up, 4 patients survived and 6 patients died. ④ The 1-year and 3-years OS rates of patients in DSI combined chemotherapy group were 57.1% and 19.0%, respectively, and those of patients in chemotherapy group were 66.7% and 17.8%, respectively. There were no significant differences between two groups (χ2 = 2.122, 0.136; P=0.58, 0.68). There was no significant difference in 1-year SAR rate between two groups (41.3% vs 29.8%; χ2=3.165, P=0.43). Conclusions The combination of G-CSF mobilized sub standard dose DSI with chemotherapy may improve the CR rate of patients with relapsed AL after allo-HSCT. Reducing dose of DSI may reduce the incidence of severe GVHD without affecting the therapeutic efficacy and graft versns leukemia(GVL) effect. Key words: Leukemia; Hematopoietic stem cell transplantation; Recurrence; Hematopoietic stem cell mobilization; Donor stem cell infusion

Long Term Outcome and Immune Function After Hematopoietic Stem Cell Transplantation for Primary Immunodeficiency.

Transplantation techniques for patients with primary immunodeficiencies have improved so that survival from the procedure in many cases is >80%. However, long term complications may arise due to the use or not of conditioning agents. This may result in variable immune reconstitution, the long term effects of chemotherapy, particularly on fertility, and complications relating to the genetic disorder, unresolved by transplantation. For patients with severe combined immunodeficiency (SCID), long term T- and B-lymphocyte immune reconstitution is best achieved after pre-transplant chemotherapy. For patients who receive an unconditioned infusion of donor stem cells, the quality of immune reconstitution depends on the SCID genotype. Long term effects include chemotherapy-induced impaired fertility, and sequelae specific to the genotype. For patients with other primary immunodeficiencies, conditioning is required—sequelae related to direct effects of chemotherapy may be observed. Additional long term effects may be observed due to partial donor chimerism resulting in incomplete eradication of disease, and other geno-specific effects.

Nutritional and Post-Transplantation Outcomes of Enteral versus Parenteral Nutrition in Pediatric Hematopoietic Stem Cell Transplantation: A Systematic Review of Randomized and Nonrandomized Studies

Hematopoietic stem cell transplantation (HSCT) involves the administration of chemotherapy followed by the infusion of donor stem cells. After treatment, children can consequently experience nausea, vomiting, diarrhea, anorexia, and mucositis, which negatively impact oral intake, leading to rapid deterioration in nutritional status and risk of malnutrition. Nutrition support therefore becomes necessary to circumvent these adverse effects. This has traditionally been provided via parenteral nutrition (PN), but pediatric evidence is increasingly advocating enteral nutrition (EN) as a preferential alternative. The objective of this review is to determine the efficacy of any forms of EN versus PN provided during admission to children aged ≤ 18 years undergoing HSCT. Primary outcomes considered efficacy in relation to various nutritional parameters, and secondary outcomes included a range of post-transplantation parameters. Data sources included English and non-English articles from the start date of MEDLINE, EMBASE, AMED, CINAHL and Cochrane Controlled Trials register, up to July 2018. Key journals were also hand searched, reference lists scanned, clinical experts contacted, and gray literature searched using EThOS and Open Grey. Randomized and observational studies comparing any forms of EN versus PN in children aged ≤ 18 years undergoing HSCT investigating nutritional or post-transplantation outcomes were eligible. Data were extracted from included studies using a custom extraction form that had previously been piloted. Because included studies were observational, risk of bias was assessed using Risk of Bias in Non-randomised Studies of Interventions. Because only a small number of heterogenous studies reporting a wide range of differently defined outcomes were included, meta-analyses were not performed and data were presented in narrative form. Conflicting results in favor of either method of nutrition support or no difference between methods were seen for duration of interventions, nutritional intakes, biochemical and anthropometric changes, mortality, infections, length of admission, and neutrophil engraftment. EN may provide favorable benefits over PN regarding acute graft-versus-host-disease (aGVHD) and platelet engraftment. A paucity of studies was found investigating the question posed by this review. Included studies were clinically heterogenous regarding populations, interventions, and outcomes, at moderate to serious risk of bias due to the absence of randomization, confounding parameters, statistical control, retrospective designs, and participant selection. Some studies were more than 15 years old. Despite the limited number and poor quality of identified studies, results support the growing body of pediatric evidence that EN is feasible during HSCT. Similar differences regarding many nutritional and post-transplantation outcomes were seen in both forms of nutrition support, but EN could provide benefits above PN including reduced incidence of aGVHD and faster platelet engraftment.

Summary of the Third International Workshop on Clinical Tolerance.

The Third International Workshop on Clinical Tolerance was held in Stanford, California, September 8-9, 2017. This is a summary of Workshop presentations of clinical trials designed to withdraw or minimize immunosuppressive (IS) drugs in kidney and liver transplant patients without subsequent evidence of rejection. All clinical protocols had in common the use of donor or recipient cell therapy combined with organ transplantation. Tolerance to HLA matched and mismatched living donor kidney transplants with complete withdrawal of IS drugs without subsequent rejection for up to 14 years of observation was achieved in more than 50 patients enrolled in trials in four medical centers after the establishment of transient or persistent chimerism. Complete IS drug withdrawal without chimerism was reported in a prospective trial of liver transplantation combined with injection of regulatory T cells. IS drug minimization without rejection was reported in recipients of living donor kidney transplants enrolled in the One Study consortium after injection of recipient regulatory T cells, or injection of donor regulatory monocytes or dendritic cells. In conclusion, considerable progress has been made in achieving IS drug withdrawal after cell therapy in recipients of organ transplants.

Receptor tyrosine kinase MerTK suppresses an allogenic type I IFN response to promote transplant tolerance.

Recipient infusion of donor apoptotic cells is an emerging strategy for inducing robust transplantation tolerance. Daily clearance of billions of self-apoptotic cells relies on homeostatic engagement of phagocytic receptors, in particular, receptors of the tyrosine kinase family TAM (Tyro3, Axl, and MerTK), to maintain self-tolerance. However, an outstanding question is if allogeneic apoptotic cells trigger the same receptor system for inducing allogeneic tolerance. Here, we employed allogeneic apoptotic splenocytes and discovered that the efferocytic receptor MerTK on recipient phagocytes is a critical mediator for transplantation tolerance induced by this strategy. Our findings indicate that the tolerogenic properties of allogeneic apoptotic splenocytes require MerTK transmission of intracellular signaling to suppress the production of inflammatory cytokine interferon α (IFN-α). We further demonstrate that MerTK is crucial for subsequent expansion of myeloid-derived suppressor cells and for promoting their immunomodulatory function, including maintaining graft-infiltrating CD4+ CD25+ Foxp3+ regulatory T cells. Consequently, recipient MerTK deficiency resulted in failure of tolerance by donor apoptotic cells, and this failure could be effectively rescued by IFN-α receptor blockade. These findings underscore the importance of the efferocytic receptor MerTK in mediating transplantation tolerance by donor apoptotic cells and implicate MerTK agonism as a promising target for promoting transplantation tolerance.

Decitabine for relapsed acute lymphoblastic leukemia after allogeneic hematopoietic stem cell transplantation.

Relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains a main question on treatment failure. Current strategies for management that usually include salvage chemotherapy, donor lymphocytic infusion and second transplantation. Our study assessed the efficacy of decitabine (DAC) for treating patients with acute lymphoblastic leukemia (ALL) who relapsed after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We retrospectively analyzed the outcomes of 12 patients with relapsed ALL after allo-HSCT who received DAC therapy. Nine patients received DAC combined with chemotherapy and donor stem cell infusion, and 3 patients received single- agent DAC. Ten of the 12 patients achieved complete remission (CR), 1 achieved a partial remission (PR), and 1 had no response (NR) after treatment at the latest follow-up (LFU), the median survival was 11.2 months (range, 3.8-34, 7 months). The 1- and 2-year overall survival (OS) rates were 50% (6/12) and 25% (3/12), respectively. Five patients were still alive; 4 had maintained CR and 1 was alive with disease. Patients with Philadelphia chromosome-positive ALL had higher survival rate than patients with Philadelphia chromosome-negative ALL (57.1% vs. 20%). No aggravated flares of graft-versus-host disease (GVHD) were observed during DAC treatment. Therefore, DAC may be a promising therapeutic agent for ALL recurrence after allo-HSCT.

Immune-Mediated Hematopoietic Failure after Allogeneic Hematopoietic Stem Cell Transplantation: A Common Cause of Late Graft Failure in Patients with Complete Donor Chimerism

Late graft failure (LGF) without evidence of residual recipient cells is a serious complication after allogeneic hematopoietic stem cell transplantation (allo-SCT) and often requires stem cell infusion from the same donor when the patient fails to respond to conventional therapies. We screened the peripheral blood (PB) of 14 patients who developed donor-type LGF at 2 to 132 months after allo-SCT for the presence of the markers for immune-mediated bone marrow (BM) failure. Increased glycosylphosphatidyl inositol-anchored protein-deficient (GPI-AP-) leukocytes, which accounted for .009% to 0.147% of the total granulocytes, were detected in 5 patients (severe aplastic anemia, n = 2; follicular lymphoma, n = 1; acute lymphoblastic leukemia, n = 1; myelodysplastic syndromes; n = 1) and 4.7% to 81.2% HLA-allele–lacking leukocytes (HLA-LLs) were detected in 2 patients (acute myelogenous leukemia, n = 1; and myelodysplastic syndromes, n = 1). Three of the 5 patients with increased GPI-AP- leukocytes were treated with antithymocyte globulin (ATG), and 2 patients achieved transfusion independence. These results suggest that immune mechanisms that are similar to acquired aplastic anemia underlie condition of approximately one-half of the patients with donor-type LGF, and that in patients with increased GPI-AP- cells, donor-derived hematopoiesis may be restored by ATG therapy alone without donor stem cell infusion.

5-Day Decitabine with Mini Fludarabine and Busulfan Yields Comparable Outcomes to Mini Flu/Bu but with Increased Incidence of Severe Acute GvHD

Background: Studies have shown that hypomethylating agents (HMAs), including 5-AZA and decitabine (Dac) are well-tolerated antileukemic agents (Kantarjian et al, JCO, 2012). Despite its myelosuppressive effect, Dac has low extramedullary toxicities, making it an attractive drug for allogeneic hematopoietic cell transplant (HCT). Reports suggest that HMAs selectively upregulate tumor associated antigens (TAAs) on malignant cells without expression in healthy tissue (Cruijsen, 2016). We previously reported on a series of 20 patients (pts) in a phase I study of 5-day Dac plus mini fludarabine and busulfan (DacMiniFluBu) in elderly or medically infirm pts (Baker et al, Blood, 2012). In the current analysis, we compared updated results from our DacFluBu study with a historical MiniFluBu control group in pts with MDS or AML.Methods: Pts were evaluated to assess engraftment, toxicity, disease response, PFS and OS. Pts received Dac 20 mg/m2/day on days (d) -15 to -11, Flu 30 mg/m2/day, on d -7 to -3 and Bu 130 mg/m2 on d -4 and -3. The control group received Flu 30 mg/m2 on d -6 to -2 and Bu 130 mg/m2 on d -3 and -2. Both groups received thymoglobulin 2 mg/kg IV on d -3, -2 and -1, followed by infusion of donor stem cells on d 0. Immunosuppression consisted of tacrolimus starting on d -2 and MTX 5 mg/m2 IV on d +1, 3, 6, and 11.Results: 107 pts were analyzed between 5/2009 and 8/2015; 36 pts received DacMiniFluBu; 17 with MDS, and 19 with AML. 23 (64%) had unrelated donors (URD); 13 (36%) had sibling donors. 71 pts were included in the MiniFluBu control group for comparison; 33 with MDS, and 38 with AML. 53 (75%) had URD; 18 (25%) had sibling donors. Median age was 68.5 yrs compared to 66 yrs, respectively. Cohorts were comparable for gender, disease and graft source. The incidence of severe (gr III/IV) acute GVHD (aGvHD) was 22% compared to the control group of 6% (p=0.0195). Moderate or severe cGVHD was seen in 7 pts vs 22 in the control group (p=0.2535). The median follow-up in the DacMiniFluBu group was 262 d, OS was 35%, relapse incidence was 28%, and NRM at 6 mos was 22%. In the control group, the median follow-up was 424 d (p=0.2213), OS was 34%, relapse was 41%, and NRM was 15%. Median time to relapse in the study vs control group was 142 and 149 d (p=0.8722). There were 22 deaths after DacMiniFluBu and 43 after MiniFluBu (p=0.7382). 6 pts in the study group received DLI at a median of 170 d post HCT for either relapse (n=3) or falling chimerism (n=3) compared to 16 pts in the control group at a median of 183 d. Multivariate analysis was performed to estimate the cumulative incidence of severe aGvHD by regimen. Results showed that conditioning regimen (HR=3.98, 95% CI, p=0.0197), degree of match (HR=1.365, p=0.039) and non-hematologic (heme) gr IV events (HR= 4.266, p=0.029) were all significant independent factors predicting a higher incidence of severe aGvHD.Conclusions: There were no significant differences in the cumulative incidences of relapse or survival between pts receiving DacMiniFluBu and MiniFluBu. However, the risk of severe aGvHD was 4 times greater in DacMiniFluBu recipients when controlling for infections, degree of match, and non-heme gr IV events. Findings were confirmed in univariate and multivariate analyses. This may be explained by the increased expression of TAAs in healthy tissues in response to Dac, which evoke T cell responses. This is the first report showing that adding Dac to the MiniFluBu regimen was an independent risk factor for severe aGvHD. Other findings in our analysis linking age, risk stratification, and degree of match to GvHD are consistent with prior reports. The differences between our results and those of other studies warrant larger validation analyses. Dac as part of a conditioning regimen should only be used in context of a clinical trial. [Display omitted] [Display omitted] [Display omitted] DisclosuresSkarbnik:Genentech: Consultancy, Speakers Bureau; Pharmacyclics: Consultancy, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau. Vesole:Amgen: Speakers Bureau; Novartis: Speakers Bureau; Celgene: Speakers Bureau; Janssen: Speakers Bureau; Takeda: Speakers Bureau. Goy:Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding; Acerta: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees; Genentech: Research Funding; Johnson & Johnson: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau; infinity: Consultancy, Membership on an entity’s Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Other: Writing support, Speakers Bureau.

BPX-501 Cells (donor T cells transduced with iC9 suicide gene) Are Able to Clear Life-Threatening Viral Infections in Children with Primary Immune Deficiencies Given Alpha/Beta T-Cell Depleted HLA-Haploidentical Hematopoietic Stem Cell Transplantation (haplo-HSCT)

Background: T-cell depleted haplo-HSCT is an established treatment for children with primary immune deficiencies (PID). However, children given this type of allograft are exposed to the risk of fatal events due to viral infections because of the prolonged impairment of adaptive immunity. We recently developed a novel method of selective T-cell depletion based on physical elimination of α/β T cells (ClinicalTrial.gov identifier: NCT01810120), which was shown to be safe and more effective than transplantation of positively-selected CD34+ cells for preventing life-threatening infections. However, we recorded some severe and even fatal viral infections, which prompted us to explore innovative approaches to accelerate the recovery of adaptive immunity. For this purpose, we designed an ongoing phase I/II trial aimed at testing the safety and the efficacy of post-transplant infusion of BPX-501 cells in children with malignant or non-malignant disorders (ClinicalTrials.gov identifier: NCT02065869). We report 3 cases of children with either severe combined immune deficiency (SCID) or Wiskott-Aldrich syndrome (WAS), who were enrolled in the dose escalation phase of the study and who cleared cytomegalovirus (CMV) or Adenovirus (AdV) infections likely due to the contribution of the BPX-501 cells.Patients and methods: Patient #1, affected by SCID, was transplanted from the HLA-haploidentical father. Before transplantation she had CMV-DNAemia which was treated with ganciclovir until donor stem cell infusion. She was given 2.5 x 105/kg BPX-501 cells on day 17 after transplantation. Patient #2, also affected by SCID, was transplanted from the HLA-haploidentical mother. Before transplantation she had AdV-DNAemia and high load of the virus in stools. She was given 5 x 105/kg BPX-501 cells on day 15 after transplantation. Patient #3 was affected by WAS and referred to the transplant unit; in the months preceding haplo-HSCT the child had developed CMV retinitis and hepatitis with high levels of CMV-DNAemia. This patient was transplanted from the father and received 1 x 106/kg BPX-501 cells on day 15 after haplo-HSCT. Basic phenotype of circulating lymphocytes was assessed by flow cytometry on fresh heparinized peripheral blood samples at 10, 20, 30, 60, 90, 120 and 150 days post haplo-HSCT, respectively. Since BPX-501 cells are CD3+/CD19+, it was easy to track the presence of these genetically modified cells. CMV specific reconstitution was also monitored through the INF gamma ELISPOT assay. In particular, peripheral blood mononuclear cells were stimulated for 16hrs in the presence of peptide libraries derived from pp65, IE1 and IE2 CMV-specific antigens.Results: The increase in the number of both CD3+ T lymphocytes and BPX-501 cells over time after transplantation together with the modifications of DNAemia of both CMV and AdV in the 3 patients are reported in Panel A, B and C, respectively, of Figure 1. In all of these patients, the pre-existing viral infection was progressively cleared once the BPX-501 cells were infused. These cells expanded in vivo and are still persisting, contributing to the recovery of adoptive immunity. The median time to reach an absolute number of α/β CD3+ cells greater than 0.5x109/L was 90, 90 and 30 days, respectively. None of these patients experienced either acute or chronic Graft-versus-Host Disease (GvHD) and no organ inflammatory-related toxicity was recorded. All children are alive and disease free, without infections, at day +200, +180 and +160, respectively. The 2 patients with CMV infection showed a specific response for at least one CMV-derived antigen; indeed, one patient showed a prevalence in pp65 response, whereas in the second one, we observed a specific anti-CMV response against all three tested antigens (Figure 1 - Panel D).Conclusions: Infusion of BPX-501 cells is able to accelerate the recovery of adaptive T-cell immunity in children with PID given haplo-HSCT after depletion of α/β T cells, thus rendering the procedure safer even in children with active infections at time of transplantation. These cells, once infused, expand in vivo and persist over time, contributing to the clearance of viral infections, without inducing GvHD. [Display omitted] DisclosuresMoseley:Bellicum Pharmaceuticals: Employment, Equity Ownership.

A Randomized Pilot Study of Donor Stem Cell Infusion in Living-Related Kidney Transplant Recipients Receiving Alemtuzumab

Transplant tolerance would remove the need for maintenance immunosuppression while improving survival and quality of life. A prospective, randomized pilot study was undertaken to assess the safety and efficacy of donor stem cell infusion (DSCI) in living-related kidney transplant recipients treated with alemtuzumab (C1H) induction and tacrolimus and mycophenolate maintenance with switch to sirolimus and weaning over 2 years. Four patients received DSCI; five patients were controls. Graft failure occurred in two patients in the DSCI arm. Recurrence of glomerular disease occurred in two DSCI recipients, leading to graft loss in one. Biopsy-proven acute rejection episodes occurred in three patients (two in the DSCI vs. one in the control). One DSCI patient, with recurrence, subsequently developed antibody-mediated rejection leading to graft failure. In the remaining two DSCI patients, weaning was attempted but was not successful. All (4 of 4) DSCI patients had biopsy-proven chronic allograft injury and/or recurrence. DSCI with C1H induction and a steroid-free maintenance regimen in a small group of patients failed to induce tolerance, with suboptimal patient and graft survival. The results do not justify extension of this particular trial and underscore the importance of patient selection, specifically avoidance of patients with glomerulopathies whose recurrence may obscure potential benefit.

Incidence and Kinetics Of Full Donor Chimerism and The Impact Of Minimal Residual Disease Status Following Outpatient Non-Myeloablative Allogeneic Stem Cell Transplantation For Myeloma

BackgroundChimerism analysis is routinely performed following allogeneic haemopoietic stem cell transplantation (allo HSCT) as a means of monitoring donor engraftment and relapse risk, although its role in the management of allografted myeloma patients is controversial. Multiparameter flow cytometry (MFC) assessment of minimal residual disease has been demonstrated to predict outcome following myeloblative autologous stem cell transplantation (ASCT) in multiple myeloma (MM). Relapse and disease progression is the principle cause of allograft failure and the detection of minimal residual disease (MRD) following tandem autologous/non-myeloablative(NMA) allo HSCT may potentially identify patients at risk of early relapse and provide a platform for early post-allograft therapy designed to further cytoreduce or enhance alloreactive T cell function and graft versus myeloma effect. AimTo evaluate the impact of MRD assessment performed at 3 months post-allo HSCT on PFS and OS and document the incidence and kinetics of full donor chimerism (FDC) in a cohort of myeloma patients undergoing tandem ASCT/outpatient non-myeloablative (NMA) allogeneic HSCT for MM. MethodsRetrospective analysis of 33 MM patients referred to our centre for tandem ASCT/outpatient NMA HSCT between May 2008 and December 2012. Patients were transplanted as part of their front line management (upfront) (n=18) if they had one or more high risk disease features (poor prognosis cytogenetics/FISH abnormalities, elevated LDH, stage III disease or less than a PR following a novel agent-containing induction regimen) or as a ‘deferred' procedure (n=15), if relapsing/progressing after an initial ASCT and maintenance/consolidation. Allo HSCT was undertaken as an ambulatory procedure and conditioned with oral fludarabine 48mg/m2 on days -4 to -2 and 2Gy TBI on day 0 followed by donor stem cell infusion, with a target CD34 dose of 2 x 106/kg and T cell dose of 3 x 108/kg. Sequential peripheral blood monitoring of CD3+ and CD33+ donor-specific chimerism was performed on days 30, 60, 90, 180 and 365 following allo HSCT. Bone marrow samples were collected for MRD analysis using MFC incorporating a CD56/CD19/CD45 panel following CD38/CD138 gating on plasma cells. MRD assessment was performed every 3 months during the first 12 months, 6 monthly during the second year and annually thereafter. ResultsThe median age for the entire cohort (M 19, F 14) was 52 years (range 39-65) and the analysis performed after a median follow up of 719 days (50-1733). All patients were transplanted using matched sibling (20/33) or unrelated donors (13/33). Non-relapse mortality was 0% at 1 year and 6% overall. At the time of analysis, 26 (79%) patients were alive including 15 (45%) in CR. The median PFS for all patients was 2.8 years and although the median OS for the entire cohort has not been reached, the estimated probability of overall survival at 4 years is 67% (95% CI: 38-85%). 29/33 (88%) patients had MRD assessments performed at least once post-allo HSCT and 4 patients progressed within 3 months prior to MRD evaluation. At the first 3 month assessment, 11/29 (38%) were MRD +, 12/29 (41%) were MRD – , results were unavailable in 3/29 (10.5%) and 3 (10.5%) patients had morphological evidence of disease. Patients achieving MRD negativity at 3 months had superior PFS in comparison to those who remained MRD positive (median 2.81 years v 1.02 years; p=0.01) but this has yet to translate into an OS advantage. The MRD + patients transplanted as a deferred procedure (n=6) had a median PFS of less than 6 months (0.47 years), suggesting this subset of patients have a particularly poor outcome, although overall numbers are insufficient to directly compare outcome according to MRD status and transplant timing. 30 (91%) patients achieved FDC (16 and 14 in the upfront and deferred groups respectively) with 2 patients not assessed. The median time to FDC for the entire cohort was 180 days (range 30-730) and there was no significant difference according to transplant timing or relationship between FDC and MRD status, GVHD, PFS or PS. ConclusionThe majority of patients undergoing outpatient-based tandem ASCT/NMA allo HSCT for myeloma achieve FDC. MRD status as assessed by MFC at 3 months post-allo HSCT appears to predict PFS and may be a useful early trigger for additional post-allograft therapy, particularly in patients with high risk disease or those transplanted later in their disease course. Disclosures:Spencer:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Tolerance Induction in HLA Disparate Living Donor Kidney Transplantation by Donor Stem Cell Infusion

We recently reported that durable chimerism can be safely established in mismatched kidney recipients through nonmyeloablative conditioning followed by infusion of a facilitating cell (FC)-based hematopoietic stem cell transplantation termed FCRx. Here we provide intermediate-term follow-up on this phase II trial. Fifteen human leukocyte antigen-mismatched living donor renal transplant recipients underwent low-intensity conditioning (fludarabine, cyclophosphamide, 200 cGy TBI), received a living donor kidney transplant on day 0, then infusion of cryopreserved FCRx on day +1. Maintenance immunosuppression, consisting of tacrolimus and mycophenolate, was weaned over 1 year. All but one patient demonstrated peripheral blood macrochimerism after transplantation. Engraftment failure occurred in a highly sensitized (panel reactive antibody [PRA] of 52%) recipient. Chimerism was lost in three patients at 2, 3, and 6 months after transplantation. Two of these subjects had received either a reduced cell dose or incomplete conditioning; the other two had PRA greater than 20%. All demonstrated donor-specific hyporesponsiveness and were weaned from full-dose immunosuppression. Complete immunosuppression withdrawal at 1 year after transplantation was successful in all patients with durable chimerism. There has been no graft-versus-host disease or engraftment syndrome. Renal transplantation loss occurred in one patient who developed sepsis following an atypical viral infection. Two subjects with only transient chimerism demonstrated subclinical rejection on protocol biopsy despite donor-specific hyporesponsiveness. Low-intensity conditioning plus FCRx safely achieved durable chimerism in mismatched allograft recipients. Sensitization represents an obstacle to successful induction of chimerism. Sustained T-cell chimerism is a more robust biomarker of tolerance than donor-specific hyporeactivity.

A Phase 2 Clinical Trial of Donor Specific Tolerance Induction in Recipients of HLA Disparate Living Donor Kidney Allografts by Donor Stem Cell Infusion

A Phase 2 Clinical Trial of Donor Specific Tolerance Induction in Recipients of HLA Disparate Living Donor Kidney Allografts by Donor Stem Cell Infusion

Non-myeloablative allogeneic transplantation with alemtuzumab, fludarabine and cyclophosphamide using 3-6/6 HLA matched donors

To broaden the proportion of patients able to undergo allogeneic therapy, we have investigated the use of 3-6/6 HLA matched family member donors in combination with donor T cell depletion in a non-myeloablative preparative regimen. Methods: Seventy five matched and 63 mismatched patients received fludarabine 30 mg/m2 IV qd × 4, cyclophosphamide 500 mg/m2 IV qd × 4, and alemtuzumab 20 mg IV qd × 5 followed by infusion of donor stem cells. In those with a matched donor, no other GVHD prophylaxis was used.

Early immunosuppression withdrawal after living donor liver transplantation and donor stem cell infusion

Long-term results of organ transplantation are still limited by serious side effects of immunosuppressive drugs. A major issue, therefore, is to elaborate novel therapeutic protocols allowing withdrawal or minimization of immunosuppressive therapy after transplantation. We report on 3 patients prospectively enrolled in an original protocol designed to promote graft acceptance in living donor liver transplantation, using posttransplant conditioning with high doses of antithymocyte globulin followed by injection of donor-derived stem cells. In 2 patients, early immunosuppression withdrawal was possible, without subsequent graft deterioration. In these 2 cases, in vitro studies showed indices of immunological tolerance as assessed by specific hyporesponsiveness to donor alloantigens in mixed lymphocytes culture. In the third patient, acute rejection rapidly occurred after discontinuation of immunosuppression, and minimal immunosuppression has to be maintained during long-term follow-up. In this case, a clearly distinct immunoreactive profile was observed as compared to tolerant patients, as no specific modulation of the antidonor response was observed in vitro. Of note, no macrochimerism could be detected in any of the 3 patients during the follow-up. In conclusion, these clinical observations demonstrated that, despite the absence of macrochimerism, donor stem cells infusion combined with recipient conditioning may allow early immunosuppression withdrawal or minimization after liver transplantation.

Effective treatment of leptomeningeal multiple myeloma with total craniospinal irradiation supported by second allogeneic donor stem cell infusion

Effective treatment of leptomeningeal multiple myeloma with total craniospinal irradiation supported by second allogeneic donor stem cell infusion

Fetal immune suppression as adjunctive therapy for in utero hematopoietic stem cell transplantation in nonhuman primates.

In utero hematopoietic stem cell transplantation could potentially be used to treat many genetic diseases but rarely has been successful except in severe immunodeficiency syndromes. We explored two ways to potentially increase chimerism in a nonhuman primate model: (a) fetal immune suppression at the time of transplantation and (b) postnatal donor stem cell infusion. Fetal Macaca nemestrina treated with a combination of the corticosteroid betamethasone (0.9 mg/kg) and rabbit thymoglobulin (ATG; 50 mg/kg) were given haploidentical, marrow-derived, CD34+ -enriched donor cells. Animals treated postnatally received either donor-derived T cell-depleted or CD34+ -enriched marrow cells. Chimerism was determined by traditional and real-time polymerase chain reaction from marrow, marrow progenitors, peripheral blood, and mature peripheral blood progeny. After birth, the level of chimerism in the progenitor population was higher in the immune-suppressed animals relative to controls (11.3% +/- 2.7% and 5.1% +/- 1.5%, respectively; p = .057). Chimerism remained significantly elevated in both marrow (p = .02) and fluorescence-activated cell sorted and purified CD34+ cells (p = .01) relative to control animals at > or = 14 months of age. Peripheral blood chimerism, both at birth and long term, was similar in immune-suppressed and control animals. In the animals receiving postnatal donor cell infusions, there was an initial increase in progenitor chimerism; however, at 6-month follow-up, the level of chimerism was unchanged from the preinfusion values. Although fetal immune suppression was associated with an increase in the level of progenitor and marrow chimerism, the total contribution to marrow and the levels of mature donor progeny in the peripheral blood remained low. The level of long-term chimerism also was not improved with postnatal donor cell infusion.