Sonali Chaudhury

Unrelated Donor Cord Blood Transplantation for Children with Severe Sickle Cell Disease: Results of One Cohort from the Phase II Study from the Blood and Marrow Transplant Clinical Trials Network (BMT CTN)

The Sickle Cell Unrelated Donor Transplant Trial (SCURT trial) of the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) is a phase II study of the toxicity and efficacy of unrelated donor hematopoietic cell transplantation in children with severe sickle cell disease (SCD) using a reduced-intensity conditioning regimen. Here we report the results for the cord blood cohort of this trial. Eight children with severe SCD underwent unrelated donor cord blood transplantation (CBT) following alemtuzumab, fludarabine, and melphalan. Cyclosporine or tacrolimus and mycophenolate mofetil were administered for graft-versus-host disease (GVHD) prophylaxis. Donor/recipient HLA match status was 6 of 6 (n = 1) or 5 of 6 (n = 7), based on low/intermediate-resolution molecular typing at HLA -A, -B, and high-resolution typing at -DRB1. Median recipient age was 13.7 years (range: 7.4-16.2 years), and median weight was 35.0 kg (range: 25.2-90.2 kg). The median pre-cryopreservation total nucleated cell dose was 6.4 × 10(7) /kg (range: 3.1-7.6), and the median postthaw infused CD34 cell dose was 1.5 × 10(5) /kg (range: 0.2-2.3). All patients achieved neutrophil recovery (absolute neutrophil count >500/mm(3)) by day 33 (median: 22 days). Three patients who engrafted had 100% donor cells by day 100, which was sustained, and 5 patients had autologous hematopoietic recovery. Six of 8 patients had a platelet recovery to >50,000/mm(3) by day 100. Two patients developed grade II acute GVHD. Of these, 1 developed extensive chronic GVHD and died of respiratory failure 14 months posttransplantation. With a median follow-up of 1.8 years (range: 1-2.6), 7 patients are alive with a 1-year survival of 100%, and 3 of 8 are alive without graft failure or disease recurrence. Based upon the high incidence of graft rejection after unrelated donor CBT, enrollment onto the cord blood arm of the SCURT trial was suspended. However, because this reduced-intensity regimen has demonstrated a favorable safety profile, this trial remains open to enrollment for unrelated marrow donor transplants. Novel approaches aimed at improving engraftment will be needed before unrelated CBT can be widely adopted for transplanting patients with severe SCD.

Fludarabine-based cytoreductive regimen and T-cell-depleted grafts from alternative donors for the treatment of high-risk patients with Fanconi anaemia

Eighteen consecutive patients aged 5·5–24 years with Fanconi anaemia and diagnoses of aplastic anaemia (n = 8), myelodysplastic syndrome (n = 4), acute myeloid leukaemia (n = 6), received allogeneic haematopoietic stem cell transplants from alternative donors. All patients had been transfused, 13 had previously been treated with androgens and 14 had a history of infection. Donors were related human leucocyte antigen (HLA) mismatched for eight patients, unrelated HLA mismatched for seven patients and unrelated HLA matched for three patients. Cytoreduction included single dose total body irradiation (450 cGy), fludarabine (150 mg/m2) and cyclophosphamide (40 mg/kg). Immunosuppression included antithymocyte globulin and tacrolimus. Grafts were granulocyte colony‐stimulating factor‐mobilized, CD34+ T‐cell‐depleted peripheral blood stem cells in 15 patients and T‐cell‐depleted marrows in three. All 18 patients engrafted with 100% donor chimaerism; only one patient developed graft‐versus‐host disease (GVHD). With a median follow‐up of 4·2 years, 13/18 patients were alive, 12 of these were disease‐free. Five‐year overall survival and disease‐free survival were 72·2% and 66·6% respectively. Immune reconstitution was achieved at approximately 6 months post‐transplant for most patients. These are encouraging results of T‐cell‐depleted transplants from alternative donors using fludarabine‐based cytoreduction in 18 high‐risk patients with Fanconi anaemia, with no evidence of rejection and minimal GVHD.

Successful Matched Sibling Donor Marrow Transplantation Following Reduced Intensity Conditioning in Children with Hemoglobinopathies

Fifty‐two children with symptomatic sickle cell disease sickle cell disease (SCD) (N = 43) or transfusion‐dependent thalassemia (N = 9) received matched sibling donor marrow (46), marrow and cord product (5), or cord blood (1) allografts following reduced intensity conditioning (RIC) with alemtuzumab, fludarabine, and melphalan between March 2003 and May 2014*. The Kaplan–Meier probabilities of overall and event‐free survival at a median of 3.42 (range, 0.75–11.83) years were 94.2% and 92.3% for the group, 93% and 90.7% for SCD, and 100% and 100% for thalassemia, respectively. Treatment‐related mortality (all related to graft versus host disease, GVHD) was noted in three (5.7%) recipients, all 17–18 years of age. Acute and chronic GVHD was noted in 23% and 13%, respectively, with 81% of recipients off immunosuppression by 1 year. Graft rejection was limited to the single umbilical cord blood recipient who had prompt autologous hematopoietic recovery. Fourteen (27%) had mixed chimerism at 1 year and beyond; all had discontinued immunosuppression between 4 and 12 months from transplant with no subsequent consequence on GVHD or rejection. Infectious complications included predominantly bacteremia (48% were staphylococcus) and CMV reactivation (43%) necessitating preemptive therapy. Lymphocyte recovery beyond 6 months was associated with subsidence of infectious complications. All patients who engrafted were transfusion independent; no strokes or pulmonary complications of SCD were noted, and pain symptoms subsided within 6 months posttransplant. These findings support using RIC for patients with hemoglobinopathy undergoing matched sibling marrow transplantation (*www.Clinical Trials.gov: NCT00920972, NCT01050855, NCT02435901). Am. J. Hematol. 90:1093–1098, 2015.

An in vivo model of double-unit cord blood transplantation that correlates with clinical engraftment

Double-unit cord blood transplantation (DCBT) appears to enhance engraftment despite sustained hematopoiesis usually being derived from a single unit. To investigate DCBT biology, in vitro and murine models were established using cells from 39 patient grafts. Mononuclear cells (MNCs) and CD34(+) cells from each unit alone and in DCB combination were assessed for colony-forming cell and cobblestone area-forming cell potential, and multilineage engraftment in NOD/SCID/IL2R-γ(null) mice. In DCB assays, the contribution of each unit was measured by quantitative short tandem repeat region analysis. There was no correlation between colony-forming cell (n = 10) or cobblestone area-forming cell (n = 9) numbers and clinical engraftment, and both units contributed to DCB cocultures. In MNC transplantations in NOD/SCID/IL2R-γ(null) mice, each unit engrafted alone, but MNC DCBT demonstrated single-unit dominance that correlated with clinical engraftment in 18 of 21 cases (86%, P < .001). In contrast, unit dominance and clinical correlation were lost with CD34(+) DCBT (n = 11). However, add-back of CD34(-) to CD34(+) cells (n = 20) restored single-unit dominance with the dominant unit correlating not with clinical engraftment but also with the origin of the CD34(-) cells in all experiments. Thus, unit dominance is an in vivo phenomenon probably associated with a graft-versus-graft immune interaction mediated by CD34(-) cells.

Primary graft failure after myeloablative allogeneic hematopoietic cell transplantation for hematologic malignancies

Clinical outcomes after primary graft failure (PGF) remain poor. Here we present a large retrospective analysis (n=23 272) which investigates means to prevent PGF and early detection of patients at high risk. In patients with hematologic malignancies, who underwent their first myeloablative allogeneic hematopoietic cell transplantation, PGF was reported in 1278 (5.5%), and there was a marked difference in PGFs using peripheral blood stem cell compared with bone marrow grafts (2.5 vs 7.3%; P<0.001). A fourfold increase of PGF was observed in myeloproliferative disorders compared with acute leukemia (P<0.001). Other risk factors for PGF included recipient age <30, HLA mismatch, male recipients of female donor grafts, ABO incompatibility, busulfan/cyclophosphamide conditioning and cryopreservation. In bone marrow transplants, total nucleated cell doses ⩽2.4 × 108 per kg were associated with PGF (odds ratio 1.39; P<0.001). The use of tacrolimus-based immunosuppression and granulocyte colony-stimulating factor were associated with decreased PGF risk. These data, allow clinicians to do more informed choices with respect to graft source, donor selection, conditioning and immunosuppressive regimens to reduce the risk of PGF. Moreover, a novel risk score determined on day 21 post transplant may provide the rationale for an early request for additional hematopoietic stem cells.

Sequential myeloablative autologous stem cell transplantation and reduced intensity allogeneic hematopoietic cell transplantation is safe and feasible in children, adolescents and young adults with poor-risk refractory or recurrent Hodgkin and non-Hodgkin lymphoma

The outcome of children, adolescents and young adults (CAYA) with poor-risk recurrent/refractory lymphoma is dismal (⩽30%). To overcome this poor prognosis, we designed an approach to maximize an allogeneic graft vs lymphoma effect in the setting of low disease burden. We conducted a multi-center prospective study of myeloablative conditioning (MAC) and autologous stem cell transplantation (AutoSCT), followed by a reduced intensity conditioning (RIC) and allogeneic hematopoietic cell transplantation (AlloHCT) in CAYA, with poor-risk refractory or recurrent lymphoma. Conditioning for MAC AutoSCT consisted of carmustine/etoposide/cyclophosphamide, RIC consisted of busulfan/fludarabine. Thirty patients, 16 Hodgkin lymphoma (HL) and 14 non-Hodgkin lymphoma (NHL), with a median age of 16 years and median follow-up of 5years, were enrolled. Twenty-three patients completed both MAC AutoSCT and RIC AlloHCT. Allogeneic donor sources included unrelated cord blood (n=9), unrelated donor (n=8) and matched siblings (n=6). The incidence of transplant-related mortality following RIC AlloHCT was only 12%. In patients with HL and NHL, 10 year EFS was 59.8% and 70% (P=0.613), respectively. In summary, this approach is safe, and long-term EFS with this approach is encouraging considering the poor-risk patient characteristics and the use of unrelated donors for RIC AlloHCT in the majority of cases.

Age-dependent pharmacokinetic profile of single daily dose i.v. busulfan in children undergoing reduced-intensity conditioning stem cell transplant

We studied the pharmacokinetic (PK) profile of single daily dose i.v. BU in children who underwent reduced-intensity conditioning (RIC) transplantation. A cohort of 19 patients ⩽4 years of age (group 1) and 33 patients >4 years (group 2) was studied. Patients received a BU test dose for PK studies, followed by two treatment doses adjusted to target an area under the curve (AUC) of 4000 μM min per day. Patients in group 1 attained a lower AUC as compared to group 2 (3568 vs 4035 μM min). In group 1, 67% patients and in group 2, 84% patients achieved AUC within the targeted range. Stable donor chimerism was achieved in 56% patients in group 1 and 79% in group 2. Eight patients required a second transplantation because of graft failure. Because of the concern that a low AUC adversely affected outcomes, a second cohort of 23 patients followed a modified protocol with a targeted AUC of 5000 μM min. A higher AUC was attained (4825 μM min). Stable donor chimerism was achieved in 91% of patients. Our results show that RIC regimens using two single daily doses of i.v. BU are effective in children, but a targeted AUC of 5000 μM min is recommended.

Liver Transplantation Followed by Allogeneic Hematopoietic Stem Cell Transplantation for Atypical Mevalonic Aciduria

Mevalonic aciduria because of mutations of the gene for mevalonate kinase causes limited synthesis of isoprenoids, the effects of which are widespread. The outcome for affected children is poor. A child with severe multisystem manifestations underwent orthotopic liver transplantation at age 50 months for the indication of end‐stage liver disease. This procedure corrected liver function and eliminated portal hypertension, and the patient showed substantial improvement in neurological function. However, autoinflammatory episodes continued unabated until hematopoietic stem cell transplantation was performed at 80 months. Through this complex therapy, the patient now enjoys a high quality of life without significant disability.

Hematopoietic Stem Cell Transplantation Activity in Pediatric Cancer between 2008 and 2014 in the United States: A Center for International Blood and Marrow Transplant Research Report

This Center for International Blood and Marrow Transplant Research report describes the use of hematopoietic stem cell transplantation (HSCT) in pediatric patients with cancer, 4408 undergoing allogeneic (allo) and3076 undergoing autologous (auto) HSCT in the United States between 2008 and 2014. In both settings, there was a greater proportion of boys (n = 4327; 57%), children < 10 years of age (n = 4412; 59%), whites (n = 5787; 77%), and children with a performance score ≥ 90% at HSCT (n = 6187; 83%). Leukemia was the most common indication for an allo-transplant (n = 4170; 94%), and among these, acute lymphoblastic leukemia in second complete remission (n = 829; 20%) and acute myeloid leukemia in first complete remission (n = 800; 19%) werethe most common. The most frequently used donor relation, stem cell sources, and HLA match were unrelated donor (n = 2933; 67%), bone marrow (n = 2378; 54%), and matched at 8/8 HLA antigens (n = 1098; 37%) respectively. Most allo-transplants used myeloablative conditioning (n = 4070; 92%) and calcineurin inhibitors and methotrexate (n = 2245; 51%) for acute graft-versus-host disease prophylaxis. Neuroblastoma was the most common primary neoplasm for an auto-transplant (n = 1338; 44%). Tandem auto-transplants for neuroblastoma declined after 2012 (40% in 2011, 25% in 2012, and 8% in 2014), whereas tandem auto-transplants increased for brain tumors (57% in 2008 and 77% in 2014). Allo-transplants from relatives other than HLA-identical siblings doubled between 2008 and 2014 (3% in 2008 and 6% in 2014). These trends will be monitored in future reports of transplant practices in the United States.

Allogeneic hematopoetic stem cell transplantation in pediatric myelodysplastic syndromes: improved outcomes for de novo disease.

Andolina JR, Kletzel M, Tse WT, Jacobsohn DA, Duerst RE, Schneiderman J, Helenowski I, Rademaker A, Chaudhury S. Allogeneic hematopoetic stem cell transplantation in pediatric myelodysplastic syndromes: Improved outcomes for de novo disease.
Pediatr Transplantation 2011: 15: 334–343.