Reduced Intensity Research Articles

Reduced intensity and non‐myeloablative allogeneic stem cell transplantation in children and adolescents with malignant and non‐malignant diseases

Allogeneic hematopoietic stem cell transplant (AlloSCT) from related or unrelated histocompatible donors has been well established as potentially curative therapy for children and adolescents with selected malignant and non-malignant diseases. In the malignant setting non-myeloablative (NMA)/reduced intensity (RI)-AlloSCT eradicates malignant cells through a graft versus malignancy effect provided by alloreactive donor T-lymphocytes and/or natural killer cells. In patients with non-malignant diseases NMA/RI AlloSCT provides enough immunosuppression to promote engraftment and correct underlying genetic defects. In children, myeloablative AlloSCT is not only associated with acute short-term toxicities but also long-term late complications such as growth retardation, infertility, and secondary malignancies. NMA/RI-AlloSCT in children may be associated with reduction in use of blood products, risk of infections, transplant-related mortality, and length of hospitalization. Despite the success of RI-AlloSCT in adults, large prospective and/or randomized multicenter studies are necessary in children and adolescent recipients to define the appropriate patient population, optimal conditioning regimens, cost-benefits, survival and differences in short-term and long-term effects compared to conventional myeloablative conditioning.

Reduced Intensity (RI) Allogeneic Hematopoietic Cell Transplantation (HCT) Improves Outcomes for Older (≥ 60 Yrs) Patients (Pts) with Acute Myeloid Leukemia (AML).

The current paradigm of cytarabine-based induction chemotherapy followed by repetitive cycles of similar consolidation has yielded 2-year disease-free survival (DFS) of no more than 20% in older pts (≥60 yrs) who achieve remission. Induction failure (IF) is also high in this population (20–35%), depending on cytogenetic risk. Regimen-related toxicities have been a barrier to allogeneic HCT in older pts. RI conditioning provides a means to harness graft vs. leukemia in this group. Between 2/2000 and 3/1/2007, 46 pts ≥ 60 yrs (median 63 yr, range 60–71) received RI HCT from either related (26) or unrelated (20) HLA matched donors. In 23 pts, RI HCT was used as consolidation of remission (CR1 [19 pts] + CR2 [4 pts]) while 23 had active disease, including 10 IF. Karyotype was favorable in 9%, intermediate in 48% and poor in 41%. The median % marrow blasts for non-remission pts was 31% (6–80%) and peripheral blood blast was 5% (0–78%). The majority (41 pts) received fludarabine (FLU)/melphalan (MEL) for conditioning. Four pts received FLU with either 200G total body irradiation (TBI) (3 pts) or busulfan (1 pt) and one received TBI alone. Graft vs. host disease (GVHD) prophylaxis was based on either cyclosporine/mycophenolate mofetil alone or with methotrexate (MTX) (20/10) or tacrolimus/sirolimus +/− MTX (2/14 pts). The graft source was peripheral blood in 43 pts and marrow in 3 pts. Engraftment occurred at a median of 15 days (0–27 days) in 98% of recipients; graft failure occurred in one sibling HCT. Donor engraftment based on DNA analysis ranged from 30–100% at 4–6 wks post-HCT (median 100%) in the 33 analyzed pts. Mortality at day 100 was 10.8%. Acute GVHD (Grade 2–4) occurred in 61% of recipients and chronic GVHD has occurred in 23/33 evaluable pts. With a median follow-up of 24.5 months (m) for surviving pts (4–83 m), 25/46 (64.5%) pts are alive. For remission pts, the 2 yr DFS is 65% (CI 51–76%). For pts who received RI HCT as “salvage”, 34% are DF at 2 yrs. (CI 27–41%). Relapse rates were 11% for remission pts and 60% for non-remission pts. Deaths post HCT were attributed to relapse in 12 pts and treatment related mortality due to GVHD (6 pts) or infection (3 pts).Conclusion: DFS can be improved for older patients with the use of RI HCT as remission consolidation. RIC also provides a meaningful salvage option for pts with IF or early relapse. Evaluation of donor options including both siblings and unrelated donors should be considered during induction for patients with good performance status.

Outcomes in the Recent Seattle Cord Blood Experience: Low TRM and Relapse; High Mild Acute GVHD and CMV Reactivation.

Studies of simultaneous transplantation of two cord blood units have suggested that as compared to single unit cord blood transplantation (CBT), increased cell dose may overcome graft rejection and improve survival, particularly in mismatched CBT, as well as enhance the graft-versus-malignancy effect. Successful double CBT has been reported following both myeloablative and reduced intensity (RIT) conditioning. However, several concerns remain, including the possibility of increased incidence of GVHD compared to single unit CBT, as well as persistent delays in hematopoietic recovery and immune reconstitution despite the increase in cell dose achieved by double CBT. We have used an algorithm to guide selection of units in our most recent cohort of CBT patients (pts), such that single unit CBT is allowed only for units matched for 5/6 HLA with total nucleated cell (TNC) dose of at least 4.0 ×107/kg or matched for 6/6 HLA with TNC at least 3.0 ×107/kg. Between February 2006 and June 2007, 22 pts underwent CBT for high risk hematologic malignancies (21 in complete morphologic remission, 8 with minimal residual disease, 1 with active mycosis fungoides). Fourteen pts median age 20.5 years (range 0.6–42) underwent myeloablative transplantation following conditioning with fludarabine (FLU) 75mg/m2, cyclophosphamide (CY) 120mg/kg, and total body irradiation (TBI) 13.2 GY. Eight pts median age 52.5 years (range 24–68) underwent RIT following FLU 200mg/m2, CY 50mg/kg, and TBI 2 GY with the addition of ATG 90mg/kg if there was no exposure to chemotherapy in the three months preceding transplant. GVHD prophylaxis was cyclosporine and MMF. Donor-recipient matching based on intermediate resolution for HLA-A and B and high resolution for HLA-DRB1 was as follows: single 5/6 unit for three pts (14%), two units 4/6 for 12 pts (55%), two units 5/6 for three pts (14%), one 4/6 and one 5/6 unit for three pts (14%), and two units 6/6 for one patient (5%). All double CBT units were at least 4/6 matched to each other. At a median follow-up of 243 days among surviving pts (range 71–451), overall survival (OS) is 77% (17/22). OS is 93% (13/14) among pts treated with myeloablative conditioning and 50% (4/8) among RIT pts. 14% (3/22) of pts have relapsed. Day 100 transplant related mortality (TRM) is 5% (1/22). Incidence of grade II–IV and III–IV aGVHD in 19 of 22 pts who had sustained engraftment and survived past day 30 are 89% (17/19) and 26% (5/19) respectively. Three pts are non-evaluable due to septic death prior to engraftment, early relapse, and graft failure. 100% (11/11) of pts seropositive for CMV prior to transplant developed CMV reactivation measured by PCR at a median of 22 days (range 3–39). No (0/11) seronegative pts developed CMV. There was one case of non-fatal CMV pneumonitis. Using this strategy, we have observed limited early TRM and a lower than expected incidence of relapse in a high-risk population. We have seen a higher incidence of a GVHD than reported at other centers, and long term monitoring for chronic GVHD will be important. Though we have observed few significant infectious complications, all seropositive patients reactivated CMV early post-transplant, emphasizing the need for close monitoring of CMV reactivation and improved treatment strategies. Ongoing experience will confirm the efficacy of our algorithm for the use of two CB units for all 4/6 HLA matched units and low dose 5/6 and 6/6 units.

Comparative Single-Institute Analysis of Cord Blood Transplantation from Unrelated Donors with Unrelated Bone Marrow or Related Peripheral Blood Stem-Cell Transplants in Elderly Patients with Hematologic Diseases after Reduced Intensity-Conditioning Regimen.

Although cord blood (CB) transplantation with reduced-intensity (RI) conditioning (RICBT) has been widely applied to those who lack available related or unrelated donors and are not eligible for conventional conditioning, indication of RICBT to elderly patients relative to other stem-cell sources is still controversial due to higher early mortality post-transplant and undefined long-term outcome. Since there has been not much data available regarding this issue, we retrospectively reviewed patients aged 55 and older who underwent RI allogeneic stem-cell transplantation at our institute from Nov. 2000 to Dec. 2006 consecutively. The study includes 121 recipients of CB (n=42), unrelated bone marrow (UBM, n=41), and related mobilized peripheral blood (RPB, n=38) for AML / MDS (n=66), ALL (n=11), CML (n=4), ML (n=31), MF (n=3), and AA (n=6). The median age for CB, UBM, and RPB recipients were 61 (range 56–69), 60 (55–70), and 60 (55–66), respectively. CB recipients had more serologically HLA-mismatched grafts (98% vs. 24% vs. 5%, P < .05), were conditioned more frequently with melphalan (90% vs. 34% vs. 32%, P < .05) and with total body irradiation (88% vs. 71% vs. 16%, P < .05), used more tacrolimus (100% vs. 71% vs. 18%, P < .05) and less methotrexate (0% vs. 76% vs. 74%, P < .05) for GVHD prophylaxis, had shorter duration of donor search (median 41 days (14–151) vs. 166 (93–345) vs. 130 (41–311), P < .05), and were transplanted more recently (2005–2006: 71% vs. 56% vs. 37%, P < .05). CB recipients tended to have high-risk disease status (76%) relative to UBM (59%) and RPB (66%) recipients, although not statistically significant. Other characteristics such as sex, diagnosis, and body weight were balanced among three groups. Median follow-up time of survivors was 554 days (25–1132), 667 days (315–1794), and 703 days (57–2214) for CB, UBM, and RPB recipients, respectively. CB recipients tended to show slower neutrophil recovery (median 19 days (12–36) vs. 16 (10–27) vs. 13 days (10–21)), and lower rate of myeloid engraftment (86% vs. 90% vs. 100%), although not statistically significant. The incidence of grades II–IV acute GVHD among evaluable CB recipients (61%) was lower than that of UBM (83%, P < .05) and comparable to that of RPB recipients (50%). The incidences of chronic GVHD for evaluable CB, UBM, and RPB recipients were 45%, 71%, and 71%, respectively (N.S.). The disease-free survival and overall survival (OS) at 2 years post-transplant were 23+/–7% and 33+/–8% for CB, 42+/–8% and 47+/–8% for UBM, and 35+/–9% and 40+/–9% for RPB recipients, respectively (N.S.). Within those who had standard risk diseases, 2-year OS were 67+/–15.7%, 48+/–13%, and 59+/–14% for CB (n=10), UBM (n=17), and RPB (n=13) recipients, respectively (N.S.). These data suggest that CB could be a viable stem-cell source for elderly patients as UBM or RPB, not just expanding opportunity of transplant. A larger-sized, randomized study is needed to further define the position of CB for this population of patients.

Once Daily Busulfan and Fludarabine Is Well Tolerated and Effective in Older Heavily Treated Patients Prior to Unrelated Donor Allogeneic Peripheral Blood Stem Cell Transplant.

Reduced-intensity (RI) preparative regimens are used to treat patients (pts) unable to receive standard myeloablative allogeneic hematopoietic stem cell transplants (HCT) due to risk factors such as older age, prior treatments, and co-morbidity. We report the results of a prospective phase II study using a RI regimen and unrelated donor HCT. The RI regimen consisted of intravenous busulfan (Bu) 3.2 mg/kg daily for 2 doses, fludarabine 30mg/m2 daily for 5 doses, and ATG 15mg/kg daily for 4 doses. GVHD prophylaxis was tacrolimus and methotrexate 15mg/m2 on day 1, and 10 mg/m2 on days 3 and 6. Twenty-one patients (median age 60, range 39–67) with acute myelogenous leukemia (n=10), non-Hodgkin's lymphoma (n=5), chronic lymphocytic leukemia (n=2), myelodysplasia (n=2), and multiple myeloma (n=2) were admitted to the study between 2002 and 2007. Nineteen pts were HLA matched with unrelated donors at A, B, C, DR, and DQ, and two pts had unrelated donors mismatched at one HLA class I allele. Nine pts had one or more autologous HCTs prior to beginning the study. Bu pharmacokinetics (pk) were performed on each dose of Bu for the first 3 pts and revealed a median Bu AUC of 5620 uM*min (range 4717–7148), Cmax 3.13 mcg/ml (range 2.68–4.62) and clearance 86.8 ml/min/kg (range 76.2–98.7). Engraftment, toxicity and follow up data is available on 20 pts. Grade II or higher regimen related toxicity (RRT) was reported in seventeen (85%) pts; gastrointestinal (n=14), mucositis (n=7), hepatic function (n=4), fever and infection (n=3), pulmonary function (n=2), and renal function (n=1). Veno-occlusive disease did not manifest in any pts. Six pts did not receive the full prescribed dosage of ATG because of ATG related toxicities, including fever and chills, hypotension, capillary leak syndrome, and elevated bilirubin levels. One pt's ANC never dropped below 0.5 x 109/L, and in the remaining nineteen patients the median day of engraftment was 15 days. Nineteen (95%) of twenty pts achieved 100% donor chimerism by day 80. Three pts subsequently lost donor chimerism and one never achieved higher than 90% donor chimerism; all 4 pts relapsed. Thirteen pts (65%) developed grade II or higher overall acute GHVD and chronic GVHD developed in five pts. Treatment related mortality (TRM) was 15% (95% confidence interval [CI], 5%–40%) at 3 months, and 35% (95% CI, 17%–63%) at 12 months. The most common cause of TRM was GVHD and infection. Actuarial overall survival at 3 years was 52% (95% CI, 27%–71%). All six pts who received reduced ATG dosages developed acute GVHD and one had relapse of disease, while of the remaining fourteen pts who received full ATG dosages 7 developed acute GVHD and 5 had relapse of disease. In conclusion, this small phase II study of a once daily Bu and fludarabine RI regimen and unrelated donor HCT demonstrated good long term survival and disease control. Once daily Bu pk studies demonstrated no unexpected AUC or clearance parameters. Significant TRM still exists with this RI regimen in this heavily treated older pt population, and future use of a co-morbidity scoring tool may help select pts more suitable for this regimen. ATG significantly contributed to RRT, while GVHD and its treatment and complications primarily resulted in the TRM. Removing ATG and using other measures for GVHD prophylaxis and treatment may improve this RI regimen.

Reduced intensity allogeneic umbilical cord blood transplantation in children and adolescent recipients with malignant and non-malignant diseases

There is a significant amount of morbidity and mortality following myeloablative umbilical cord blood transplantation (UCBT). Reduced intensity (RI) conditioning offers an alternative to myeloablative conditioning before UCBT. We investigated RI-UCBT in 21 children and adolescents with malignant (n=14), and non-malignant diseases (n=7). RI conditioning consisted of fludarabine (150-180 mg/m2) with either busulfan (< or = 8 mg/kg)+rabbit antithymocyte globulin (R-ATG; n=16) or cyclophosphamide+R-ATG+/-etoposide (n=5). Human leukocyte antigen match: 4/6 (n=13), 5/6 (n=5) and 6/6 (n=3). The median total nucleated cell and CD34+ cell dose per kilogram were 3.58 x 10(7) and 2.54 x 10(5), respectively. The median time for neutrophil and platelet engraftment was 17.5 and 52 days, respectively. There were six primary graft failures (chronic myelogenous leukemia (CML), beta-thalassemia, hemophagocytic lymphohistiocytosis (HLH) and myelodysplastic syndrome (MDS)). The probability of developing grade II to grade IV acute graft-versus-host disease (GVHD) and chronic GVHD was 28.6 and 16.7%, respectively. Incidence of transplant-related mortality (TRM) was 14%. The 5 years overall survival (OS) in all patients was 59.8%. The 5 years OS for patients with average versus poor-risk malignancy was 77.8 versus 22.2% (P=0.03). RI-UCBT may result in graft failure in specific high-risk chemo-naïve patients (CML, beta-thalassemia, HLH and MDS), but in more heavily pretreated pediatric and adolescent recipients results in rapid engraftment and may be associated with decreased severe GVHD and TRM.

Reduced intensity compared with high dose conditioning for allotransplantation in acute myeloid leukemia and myelodysplastic syndrome: A comparative clinical analysis

We evaluated the efficacy of hematopoietic stem cell transplantation (HSCT) using reduced intensity (RI) vs. myeloablative (MA) conditioning for patients with acute myeloid leukemia (AML) and myelodysplastic syndrome. Thirty two patients (median age 54) who underwent a RI HSCT (2000-2003) were compared with 187 patients (median age 39) who received a MA transplant (1990-2003). Neutrophil engraftment was more rapid in the RI group (median 11.5 vs. 21 days). Platelet recovery was similar and graft failure was infrequent. The incidence of graft-versus-host disease (GVHD) and treatment-related mortality was similar though relapse was more frequent after RI conditioning (RR 2.2 [95% CI = 1.1-4.6] P = 0.03). At 2 years, disease-free survival (DFS) (31% vs. 30%, P > 0.1) and overall survival (33% vs. 35%, P > 0.1) were comparable between RI and MA groups, respectively. We suggest that RI allografts can yield satisfactory DFS both for older as well as younger patients with pre-existing comorbidities, who are ineligible for MA allografts. Advances in GVHD management and new approaches for relapsed or refractory disease are necessary to improve these outcomes.

A pilot study of myeloablative (MA) autologous stem Cell (Auto SCT) followed by reduced intensity (RI) allogeneic transplantation (AlloSCT) in children with relapsed/refractory(R/R) Hodgkin’s disease (HD)

20007 Background: Allo SCT may benefit patients with R/R HD by providing a graft vs lymphoma effect. Peggs et al (Lancet 2005) demonstrated durable engraftment and reduced non relapse mortality (NRM) in HD pts post RI Allo SCT. Carella et al (JCO2000) and Gutman et al (BMT2005) demonstrated the success of MA Auto SCT followed by RI AlloSCT in adults with refractory lymphoma. We investigated the feasibility of MA Auto SCT followed by RI Allo SCT in children with R/R HD. Methods: MA conditioning prior to AutoSCT was CTX 1,500 mg/m2 x 4 d, BCNU 100 mg/m2 x 3d, VP-16 800 mg/m2 x 3d. AlloSCT conditioning was fludarabine 30 mg/m2 x 5d, busulfan 3.2 mg/kg x 2d, and R ATG 2 mg/kg x 4d (unrel. donor). CD20+ patients received rituximab (375 mg/m2/wk x4) and all pts received involved field radiotherapy (IFRT). Results: Ten pts have enrolled, 2 pts did not proceed (parental withdrawal) to RI AlloSCT (Donors: 1 MRD, 2 MUD, 5 UCB). Median time to RI AlloSCT after MA Auto SCT was 142 d (97–219). The median cell dose was 3.43 x 107 TNC/kg for UCB grafts (n=5). Engraftment was achieved at a median of 20.5 d for PMN and 46.5 d for PLT. Donor chimerism reached ≥ 95% in all pts by day 100 with a median follow up of 703d (128–2025). Toxicities were grade (3) hematuria (n=1), (3–4) infection (n=7), (4) pulmonary fibrosis (n=1), (4) hearing loss (n=1), (4) neurotoxicity (n=1). GVHD: grade II-III aGVHD (3/8), cGVHD (3/8). Six patients are alive and NED post allo SCT. There has been one NRM (cGVHD) and one relapse mortality. The OS at one year is 66.7%. Conclusions: MA AutoSCT followed by RI AlloSCT is feasible and well tolerated in pediatric pts with R/R HD. A larger study with longer follow up is required to determine if this approach will reduce relapse, long term toxicity and/or improve survival. No significant financial relationships to disclose.

Multiple Reduced-intensity Conditioning Regimens Facilitate Correction of Fabry Mice After Transplantation of Transduced Cells

Hematopoietic cell transplantation can impact lysosomal storage disorders (LSDs) and will be enhanced by gene therapy. Transduced cells in LSDs often secrete the therapeutic hydrolase, which can be used by bystander cells. However, toxicity associated with myeloablative transplant preparative regimens limits many applications of this approach in gene therapy. We hypothesized that reduced-intensity (RI) conditioning regimens would allow stable engraftment of therapeutically transduced cells and allow correction of Fabry disease. We transplanted transduced cells into Fabry mice receiving eight different clinically relevant chemotherapy- and/or radiotherapy-based RI conditioning regimens generating modest and transient lymphoid/myeloid cell depletion. Two comprehensive transplantation Protocols were performed. Firstly, transplantation of 0.38 x 10(6) gene-modified stem/progenitor cells was nominally effective; none of the RI regimens led to stable alpha-galactosidase A (alpha-gal A) correction. Secondly, transduced cells were preselected for functional transgene expression and transplanted at a higher dose (0.72 x 10(6) cells). Each RI regimen yielded engraftment of functional transgene-positive cells through 180 days along with increased plasma alpha-gal A activity. Importantly, the RI regimens mediated broad organ enzyme correction and were not associated with immune responses against alpha-gal A. RI conditioning thus has an important role in gene therapy for LSDs; a variety of regimens can be effective in this context.

76: Reduced intenity allogeneic stem cell transplantion followed by targeted consolidation immunotherapy with gemtuzumab ozogamicin in children and adolescents with CD33 + acute myeloid leukemia

Myeloablative allogeneic stem cell transplant (MA AlloSCT) for childhood AML may be associated with significant acute toxicity, late effects and/or recurrent disease (Woods et al; Blood, 2001). Reduced intensity (RI) AlloSCT may offer less acute toxicity and/or reduced late effects for children with cancer (Del Toro/Cairo et al; BMT, 2004, Satwani/Cairo, BBMT, 2005). Gemtuzumab ozogamicin (GO) has induced responses in >30% of patients with recurrent CD33+ AML (Sievers et al; J Clin Oncol, 2001).

Reduced Intensity Hematopoietic Stem Cell Transplantation for Treatment of Class 3 Lucarelli Severe Thalassemia Patients.

Approximately 80% of children with severe thalassemia (thal) were cured with hematopoietic stem cell transplantation (HSCT). However, initial reports suggested that a subset of patients (pts) had poorer outcomes, and were more likely to experience transplant-related mortality or recurrence. These were older pts who had evidence of organ damage from iron-overload and were classified as class 3 Lucarelli pts. One approach to reduce the mortality that has been tested in limited series is reduced intensity (RI) HSCT, which relies upon immunosuppressive rather than ablative pre-transplantation conditioning to facilitate engraftment of donor cells. We conducted RIHSCT in 8 severe thal pts with class 3 lucarelli. All were older than 10 yrs of age (median 12.5 yrs; range 10 – 18) and received blood more than 100 transfusions. Three pts had homozygous β thalassemia and 4 had β thalassemia/hemoglobin E. Five of these pts had splenectomy. The conditioning regimen; busulfan 12 mg/kg orally, iv. fludarabine 175–180 mg/m2, antithymocyte globulin (ATG) (Fresineus®) 40 mg/kg, was given in all pts. In addition, one pt (pt 2) also received thiotepa 10 mg/kg and single fraction total lymphoid irradiation (TLI) 500 cGY and one (pt 1) also received. TLI. All pts received hydroxyurea 20 mg/kg at least for 6 months prior to transplant in order to suppress erythroid expansion. Seven pts received peripheral blood stem cells (PBSC) from 6 HLA antigens matched siblings and 1 (Pt2) received T cell depleted PBSC by CD34+ selection from 4 HLA antigens matched mother. The median number of infused CD34+ cell was 9 × 106cells/kg (range 6.5 – 15 × 106). GvHD prophylaxis regimen was with cyclosporin or tracolimus and MMF. All pts can achieve full donor engraftment. Median time of neutrophil engraftment was 11 days (range 11– 14), and platelet was 14 days (range 12–24). Two pts did not have neutrophil count less than 0.5 × 109/L and four did not have platelet count less than 20 × 109/L. Four pts did not have acute GvHD, 3 had gr I and 1 had gr II. Only 1 pt had limited chronic GvHD. All pts had no major toxicity except pt 2 who developed CMV retinitis but it was resolved. The 2 yr thal free survival rate is 88% (95%CI: 39 %, 98 %) and the 2 yr overall survival rate is 100%. The median time of follow up was 10 months (range: 3 – 63). Currently, 6 pts had full donor chimerism, one had mixed chimerism and one had graft rejection. We would like to suggest that busulfan, fludarabine, and ATG together is the backbone of RIHSCT conditioning regimen for class 3 lucarelli pts. Since 2 (pt 7 and pt 8) out of three pts who did not have splenectomy prior to transplant, had mixed chimerism and one of these 2 pts finally had graft rejection, we, therefore, plan to add either another agent such as thiotepa or melphalan or TLI in our backbone RIHSCT conditioning regimen for the pts who do not have splenectomy prior to transplant in the future to achieve the sustainable engraftment.Donor chimerism study, Recent outcome, and Follow up timePtDay + 15Day + 30Day + 60Day + 100Recent OutcomeF/U time (months)1MFFFA with F632FFFFA with F473FFFFA with F394FFFFA with F125FFFFA with F86FFFFA with F77FMLLA with L48FFMN/AA with M3M = mixed chimerism, F = full donor chimerism, L = loss of donor chimerism, A = alive, F/U = follow up, N/A = not applicable

3: Reduced Intensity (RI) aLlogeneic Cord Blood Hematopoietic Cell Transplantation (Allo-CBHCT) in Pediatric Patients with Malignant and Non-Malignant Diseases

3: Reduced Intensity (RI) aLlogeneic Cord Blood Hematopoietic Cell Transplantation (Allo-CBHCT) in Pediatric Patients with Malignant and Non-Malignant Diseases

Targeted immune depletion prior to reduced-intensity allogeneic stem cell transplantation results in rapid and complete donor chimerism with low treatment-related mortality

6540 Background: Significant variation in host immune status may influence outcomes after reduced-intensity (RI) allogeneic stem cell transplantation (alloSCT). We have investigated a strategy of targeted immune depletion (TID) with conventional chemotherapy to deplete host T cells and achieve a minimal disease state prior to RI alloSCT. The aim of TID is to rapidly establish complete donor chimerism after RI alloSCT in order to potentiate a graft-versus-tumor (GVT) effect. In a prospective phase II trial (NIH 03-C-0077), we evaluated the effect of TID on donor chimerism, acute graft-versus-host disease (GVHD), and clinical outcome. Methods: Thirty-one patients (pts) with relapsed and refractory hematologic malignancies (NHL = 16; HL = 4; CLL/PLL = 4; MDS/AML = 3; other = 4) were enrolled. Median age was 57 years (range: 31–71). All pts received EPOCH-F (etoposide, prednisone, vincristine, cyclophosphamide, adriamycin, fludarabine) ± rituximab (R) as TID to deplete host CD4+ cells &lt;100/μL. All pts then received a RI conditioning regimen consisting of fludarabine and cyclophosphamide followed by a T-cell replete allograft from HLA-matched siblings. GVHD prophylaxis consisted of cyclosporine plus short-course mini-methotrexate. Results: EPOCH-F(R) achieved the target host T-cell level in 74% of pts. All 31 pts engrafted after RI alloSCT. Complete donor chimerism (&gt; 95%) was observed in 74% and 81% of pts at day +14 and +28 post-transplant, respectively. The incidence of grade II-III acute GVHD was 42% with no cases of grade IV acute GVHD. The median potential follow-up from transplant is 25 months. Actuarial treatment-related mortality at 1 and 2 years was 3% and 8%, respectively. Event-free survival probabilities at 1 and 2 years post-transplant are 65% and 49%, respectively. Ten pts are alive and event-free &gt;24 months post-transplant. The overall survival probabilities at 1 and 2 years are 84% and 64%, respectively. Conclusions: TID prior to RI alloSCT results in rapid, complete donor engraftment and may potentiate GVT effects. This treatment strategy was associated with very low TRM and favorable outcomes in an older patient population with advanced hematologic malignancies. No significant financial relationships to disclose.

Reduced-intensity allogeneic stem cell transplantation for diffuse large B-cell lymphoma: Clinical evidence of a graft-versus-lymphoma effect

6546 Background: Despite being the most common non-Hodgkin’s lymphoma, there have been no specific reports on the use of reduced-intensity (RI) allogeneic stem cell transplantation (alloSCT) to treat patients (pts) with diffuse large B-cell lymphomas (DBCL). This may be due to a lack of definitive evidence for a therapeutic graft-versus-lymphoma (GVL) effect against DLBC. We undertook a retrospective analysis to assess clinical outcomes and evidence of a GVL effect in DLBC pts undergoing RI alloSCT. Methods: The analysis was limited to 18 pts with primary refractory (n = 6) or relapsed (n = 12) DLBC. The median age was 43 years (range: 31–61); median number of previous treatments was 3 (range: 2–9). Nine (50%) pts had undergone autologous transplantation. Three (16%) pts were determined to have chemo-sensitive disease to last treatment prior to RI alloSCT. All pts received a RI conditioning regimen consisting of fludarabine (30 mg/m2/d × 4d) and cyclophosphamide (1200 mg/m2/d × 4d) followed by a T-cell replete allograft from HLA-matched siblings. Results: Median potential follow-up from transplant is 43 months. Seven (39%) pts developed grade II-IV acute GVHD. Response at day +100 post-transplant was as follows: complete response (CR/CRu) = 5; partial response = 5; progressive disease = 8. Nine of 17 (53%) evaluable pts developed chronic GVHD. Median progression-free survival (PFS) was 4.8 months; however, PFS after 9 months post-transplant was 31% with 5 pts in continuous CR/CRu &gt; 12 months post-transplant. Among 14 pts who were not in CR/CRu (n = 12) or progressed after achieving a CR/CRu (n = 2) at day +100 post-transplant, 8 (57%) subsequently achieved a CR/CRu after removal of immune suppression and/or donor lymphocyte infusion (DLI) ± chemotherapy. Seven of these 8 pts remain in continuous (median = 34 months; range: 6–55+) CR/CRu without further treatment. Median survival for all 18 pts was 19 months with survival probability of 40% plateauing at 25 months post-transplant. Conclusions: The clinical observations of sustained CR/CRu after withdrawal of immune suppression and DLI suggest that a GVL effect exists against DLBC. RI alloSCT should be considered as a treatment option for pts with primary refractory and relapsed DLBC. No significant financial relationships to disclose.

Reduced intensity (RI) allogeneic cord blood hematopoietic cell transplantation (Allo CBHCT) in pediatric patients with malignant and non-malignant diseases

Reduced intensity (RI) allogeneic cord blood hematopoietic cell transplantation (Allo CBHCT) in pediatric patients with malignant and non-malignant diseases

A pilot study of myeloablative (MA) autologous stem cell (autoSCT) followed by reduced intensity (RI) allogeneic transplantation (AlloSCT) in children and adolescents with relapsed hodgkin’s disease (HD) and non-hodgkin’s lymphoma (NHL)

AlloSCT may be beneficial to patients with relapsed/refractory HD and NHL by providing a graft versus lymphoma effect. Carella et al (JCO 2000) and Gutman et al (BMT 2005) demonstrated the feasibility and success of MA AutoSCT followed by RI AlloSCT in adults with refractory lymphoma. We investigated MA AutoSCT followed by RI AlloSCT in children with relapsed/refractory HD/NHL. Twelve patients entered post reinduction therapy (3CR+2PR post Ifos/Carbo/VP-16, 1PR+1CR post Ifos/Vinorelbine, 1PR post Topotecan/Ifos/Carbo, 1CR post vinorelbine/gemcitabine, 1PR post cytarabine/VP-16/MTX, 1PR post cytarabine/VP-16/L-asp/prednisone, 1CR post carmustine/VP-16/cyclophosphamide).

Reduced-Intensity Conditioning Followed by Unrelated Umbilical Cord Blood Transplantation for Advanced Hematologic Malignancies: Rapid Engraftment in Bone Marrow

Reduced-intensity (RI) conditioning followed by cord blood transplantation (CBT) is a new treatment modality, but failure to engraft is a major concern. We describe 12 patients with advanced hematologic malignancies who underwent RI conditioning and CBT with a conditioning regimen consisting of 200 mg/m(2) fludarabine (Flu), 50 mg/kg cyclophosphamide (CY), and 3 Gy total body irradiation (TBI). Cyclosporin A and/or methotrexate were used for graft-versus-host disease prophylaxis. Cord blood grafts were not mismatched for more than 2 serologically defined HLA alleles but were later found by high-resolution DNA typing to be mismatched for 2 to 4 alleles in most cases. Short tandem repeat analysis of bone marrow cells at day 14 showed complete donor chimerism in 6 of the patients and mixed chimerism in 5, indicating rapid engraftment in the bone marrow, whereas the remaining patient experienced graft rejection. Neutrophil recovery was achieved at a median of day 17 (range, days 11-24) in 10 of the 11 patients with marrow chimerism at day 14. Of these 10 patients, however, transplantation-related mortality within 100 days occurred in 4 patients who showed failed platelet recovery and a lack of durable engraftment. Overall survival and disease-free survival rates were 41.7% and 33.3%, respectively. These results show that CB mismatched at 2 to 4 HLA alleles and transplanted with the Flu/CY/3 Gy TBI regimen is able to engraft in the bone marrow as early as day 14.

Reduced Intensity (RI) Allogeneic Cord Blood Hematopoietic Cell Transplantation (Allo CBHCT) in Pediatric Patients with Malignant and Non-Malignant Diseases.

We and others have demonstrated that cord blood hematopoietic cells can be used successfully as an alternative allogeneic progenitor cell source in pediatric and adult recipients with both malignant and non-malignant diseases (Cairo et al, Blood 1997). However, there is significant amount of morbidity and mortality following myeloablative CBHCT (Gluckman et al, NEJM 1997; Rubinstein et al, NEJM 1998). RI conditioning may potentially reduce the incidence of regimen-related mortality (RRM) and the late effects associated with myeloablative regimens without increasing the risk of graft failure or relapse in children and adolescents (Del Toro et al, BMT 2004). Successful engraftment has been demonstrated in adult recipients with advanced hematologic malignancies who received unrelated mismatched cord blood following RI conditioning regimens (Chao et al, BBMT 2004). We report the results in 22 pediatric recipients, 6F:16M, median age 6.5 years (0.4–21). Twenty-one received unrelated CBHC, the majority mismatched at 1–2 HLA-Loci, 4/6 (n=14), 5/6 (n=5), 6/6 (n=2); 1 sibling CBHC (6/6). Recipients were transplanted for malignant n=17, [HD (5), NHL (2), NB(4),AML (2), MDS(3),CML (1)] and non-malignant n=5, [b-thal (1), HLH (2), WAS (1), SCD(1)] diseases. Poor-risk disease was defined as induction failure, PD, SD, ≥CR3, and 2nd allo HCT (n=8). RI conditioning was fludarabine-based (150–180mg/m2) with either busulfan (8mg/kg) +/− rabbit ATG/alemtuzumab or cyclophosphamide +/− etoposide/etoposide phosphate +/− ATG and craniospinal radiation prophylaxis (n=1). Graft-vs.-host-disease (GHVD) prophylaxis: tacrolimus 0.03 mg/kg/day and mycophenolate mofetil 900mg/m2 q 6h (Osunkwo et al, BBMT 2004). Median total nucleated cell count was 3.8 x107/kg (0.92–10.82) and CD34 cell count was 2.2 x105/kg (0.34–6.95). The median day to neutrophil engraftment was 19.5 days (1–47) and to platelet engraftment was 40 days (6–170). Engraftment was 72.7%. There were 6 primary graft failures observed (1 CML, 1 b-Thal, 2 HLH, 1 MDS, and 1 AML). Within this subgroup of graft failures, 4 were regrafted with myeloablative conditioning followed by a second CBHCT and 100% engrafted. Of the 16 engrafted patients, 15 achieved 90% or greater mixed-donor chimerism by day 60. Five of 16 evaluable patients developed acute GVHD, with 3 of those 5 developing grade III/IV acute GVHD. One patient developed extensive chronic GVHD. There were 8 deaths (4 PD, 1RRM, 3 GVHD). The probability of 3-year overall survival (OS) in all patients was 61%. Despite a log less nucleated cells/kg with CB vs. PB or BM HCT, the 3-yr OS in standard-risk malignancy pts. was 90%. The 1-yr OS in poor-risk malignancy pts. was 21%. The 1-yr OS in non-malignant diseases was 75%.These preliminary results indicate that RI Allo CBHCT may result in more rapid hematopoietic reconstitution while decreasing RRM compared to myeloablative CBHCT and be associated with high-to-full mixed-donor chimerism. Patients with diseases such as CML, β-Thal, and HLH may require increased intensity of conditioning. Further follow-up is required to evaluate the difference, if any, in long-term effects following RI Allo CBHCT.

Prognostic Factors for the Engraftment in Cord Blood Transplantation: With Units Shipped from Single Cord Blood Bank, Tokyo Cord Blood Bank.

The better selection of cord blood (CB) unit in recent varied cord blood transplantation (CBT) is crucial for the success of CBT, although it is difficult to compare the units from different cord blood bank (CBB). Here, we analyzed the prognostic factors by age for engrafment in CBT with the units shipped from single CBB, Tokyo Cord blood bank.Patients and Methods: Units were all processed by HES centrifugation method and cryopreserved with 10% DMSO and Dextran 40 in Tokyo CBB. CD34 was analyzed by gating CD45dim CD34+ with DNA dye or 7-AAD in Trucount beads tube (BD). Patients characteristics are shown in table. Group I included 58u for malignancies and 25 for non-malignancies. Group III included 22 full(Full) vs.22 reduced intensity (RI) conditioniong regimen for malignancies and remaining ones with further reduced intensity regimens. RI regimen consisted maily with reduced dose of TBI (<8Gy) and BU/Melphalan with fludarabin.Results: Myeloid engraftment in malignancies with Full regimen was seen at 84.3%(median 28days) in Group I, 82.5%(25days) in Group II and 73.0%(30days) in Group III, respectively, whereas with RI regimen in Group III was 67.8%(24days). The patients with non-malignancies in Group I showed 75.0% (26days) of engraftment by Full regimen(n=12) and 100% (24days) by RI regimen(n=8), respectively. HLA disparities had no significant influence on the engraftment in Group I and II. The dose effects of NC and CD34+ cells on the rate and the speed of engraftment were seen in Full regimen in Group I and II for malignancies. Critical dose of CD34+ cells seemed 0.8x105/kg. Even in Group I(children), the patient with CD34+ less than 0.8x105/kg showed 79.6%(43days), whereas those with more than 0.8x105/kg, 85.7%(24days). There was no difference of speed and rate of engraftment between the patients with CD34+ cells 0.8~1.6x105/kg and those with more than 1.6x105/kg. Interestingly, this effect vividly influenced on the engraftment in the patients with RI regimen of Group III. The patients with CD34 + with less than 0.8x105/kg showed only 22.9% of final engraftment, whereas those with over 0.8x105/kg 100% (19 days) in Group III. The dose of CD34+ had some influeced on the survivals, although the main prognostic factors on the long-term survivals was the risk factor of malignancy and age.Conclusion: CD34+ cell dose should be given high priority for the selection of CB unit, especially in reduced intensity regimen.Patients CharacteristicsNo. of PatientsGroup I ( ~ 15 y.o.) n=83Group II (15 ~ 50 y.o.) n = 76GroupIII (51 y.o. ~)Age y.o.5.23±4.8133.9±10.458.3±12.8BM (kg)19.7±14.252.0±9.154.0±13.5Dose of NC (x10^7/kg)6.17±3.982.63±0.662.76±1.10Dose of CD34 (x10^5/kg)1.80±1.750.81±0.460.91±0.95HLA mismatch01854(rejection direction)151331921435233030

Reduced Intensity Compared to High Dose Conditioning for Allotransplantation in Acute Myeloid Leukemia and Myelodysplastic Syndrome: A Comparative Clinical Analysis.

We evaluated the comparative safety and efficacy of stem cell transplantation using reduced intensity (RI) vs myeloablative (MA) conditioning for patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) who underwent allogeneic hematopoietic stem cell transplantation (HSCT). Thirty two patients [18 males, median age 54 (range 19–69)] underwent a RI HSCT from January 2000- September 2003, and these were compared to 187 patients [93 males, median age 39 (range 18.4–60.3)] who received MA transplants between January 1990 – September 2003. Disease status in the 2 groups was similar, (AML in CR1: RI 38% vs MA 38%; CR2: 22% vs 15%; AML relapse: 13% vs 20% and MDS 28% vs 27%). Patients were eligible for RI if age &gt;55 with HLA matched sibling donor (Sib) or &gt;45 with unrelated bone marrow (BM) or umbilical cord blood (UCB) donor; extensive previous therapy including previous transplant or major co-morbidity. RI donors were Sib (n=17, 53%), unrelated UCB (n=14, 44%), or unrelated BM (n=1). MA donors were Sib (n=176, 94%) and UCB (n=11, 6 %), p&lt;0.01. RI conditioning included an alkylator (busulfan (Bu) or cyclophosphamide (Cy), a nucleoside analogue (fludarabine or cladribine) and 200 cGy total body irradiation (TBI), while MA conditioning was Cy/TBI (1320 cGy) (n=177) or Bu/Cy (n=10). Median follow up is 1.7 years in RI recipients and 4.2 years in MA. Neutrophil engraftment was more rapid in the RI group (median =11.5 days vs 21 days) with 3% and 6% graft failure respectively in the RI and MA groups. The cumulative incidence of Grade III–IV acute graft versus host disease (GVHD) was 22%±14% in RI vs 12±4% after MA HSCT. The cumulative incidence of relapse or disease progression at 1 year was 31% after RI vs 22% after MA HSCT (p=0.06). Disease free survival (DFS) at 1 year was 31± 16% in RI and 37%± 7% in the MA group (p=0.14). Multivariate regression analysis showed that neither conditioning intensity (NST RR=1.4, p=0.14) nor donor choice (UCB RR 0.9, p=0.63) significantly altered DFS. More failures (relapse or death) followed transplant for AML in relapse (RR=1.5, p=0.05), recipient seropositive for CMV (RR1.4, p=0.03) and development of Grade III/IV GVHD (RR 1.9, p&lt;0.01), with MDS having an outcome similar to AML in remission (RR 1.2,p=0.28). These data suggest that allografts for AML or MDS using RI conditioning, even for older patients or using unrelated UCB can yield satisfactory outcomes and extended DFS. Advances in GVHD management and new approaches for patients in relapse are needed to improve these outcomes.