Pharmacokinetics of a Test Dose of Intravenous Busulfan Guide Dose Modifications to Achieve an Optimal Area Under the Curve of a Single Daily Dose of Intravenous Busulfan in Children Undergoing a Reduced-Intensity Conditioning Regimen with Hematopoietic Stem Cell Transplantation

Abstract Administration of oral BU is a challenge in pediatric patients. The I.V preparation can improve compliance and eliminate variability in absorption. The metabolism and clearance of BU is age dependant. A prospective trial using a single daily dose of I.V. BU as part of a reduced Intensity Regimen was undertaken. Patients were enrolled after proper informed consent was signed... The regimen consisted of a test dose of BU (0.8mg/kg as a 2 hr infusion) on day -10, Fludarabine 25mg/m2/day from day-10 to -5, BU 3.2 mg/Kg/Day on days -5 ,-4.and rabbit ATG 2mg/kg daily on days -4 to-1. Cells were infused on day 0. The stem cell source were UCB (n=4), MUD (n=7) and MSD (n=1). PK samples (2, 4, 6,8,12 hrs) were obtained and submitted to the Seattle Cancer Care Alliance for determination of the Area Under the Curve (AUC) and clearance for BU. Twelve patients were enrolled (8F, 4M), median age 8 (0.5–16), median weight 22.6 kg (4.3–58.8) with the following diagnoses: Neuroblastoma (n=3), ALL (n=3), CML (n=2), Aplastic Anemia and X linked Lymphoprolipherative Disease, Ommen’s syndrome, Severe Combined Immune Deficiency. An AUC of 800–1200 and 3200–4800 uMol*min were targeted for the test dose and the single daily dose respectively. The median AUC for the test dose was 1003 uMol*min (804–1315), and the median clearance was 3.1 (ml/min)/Kg (2.4–7.3). The median AUC for the single daily dose was 3512 uMol*min (1511–4097) and the clearance 3.4 (ml/min)/kg (2.8–6.8). After the test dose 4 patients had their dose adjusted (2 patients lower and 2 patients higher). In the very young patients (< 1 year of age) the AUC of the single daily dose could not be predicted due to abnormal clearance. No instances of VOD or seizures were observed. Full donor chimerism was achieved in 8 patients in a median of 23 days (14–53), 2 patients developed graft failure, 1 patient was not evaluable for engraftment due to early TRM from pre-existing CMV pneumonia and 1 patient is too early. In conclusion, a single daily dose of I.V. BU is feasible, a test dose can be a predictor of the single daily dose AUC except in the very young, No regimen related toxicity was observed and engraftment was prompt and complete in 8 evaluable patients.

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Rapid Immune Reconstitution after a Reduced-Intensity Conditioning Regimen and a CD3-Depleted Haploidentical Stem Cell Graft for Pediatric Refractory Hematologic Malignancies.

Blood ◽

10.1182/blood.v108.11.5311.5311 ◽

2006 ◽

Vol 108 (11) ◽

pp. 5311-5311

Author(s):

Xiaohua Chen ◽

Gregory A. Hale ◽

Raymond C. Barfield ◽

Ely Benaim ◽

Wing H. Leung ◽

...

Keyword(s):

Stem Cell ◽

Nk Cells ◽

Immune Reconstitution ◽

Acute Gvhd ◽

Conditioning Regimen ◽

Hematologic Malignancies ◽

Reduced Intensity Conditioning ◽

Hematopoietic Stem ◽

Reduced Intensity Conditioning Regimen ◽

Reduced Intensity

Abstract Haploidentical hematopoietic stem cell transplantation (HaploHSCT) from a mismatched family member (MMFM) donor offers an alternative option for patients who lack an HLA-matched donor. The main obstacles to successful haploidentical hematopoietic stem cell transplantation from a mismatched family member donor are delayed immune reconstitution, vulnerability to infections, and severe graft-versus-host disease (GvHD). Method: We designed a reduced-intensity conditioning regimen that excluded total body irradiation and anti-thymocyte globulin. The graft was immunomagnetically depleted of CD3+ T-cells (CD3 negative selection) and contained a large number of both CD34+ and CD34− stem cells and most other immune cells especailly NK cells. This protocol was used to treat 22 pediatric patients with refractory hematologic malignancies. Results and Discussion: After transplantation, 91% of the patients achieved full donor chimerism. They also showed rapid recovery of CD3+ T-cells, T-cell receptor excision circle counts, TCRβ repertoire diversity and NK-cells during first four months post-transplantation. The incidence and extent of viremia were limited and no lethal infection was seen. Only 9% of patients had grade 3 acute GvHD, while 27% patients had grade 1 and another 27% had grade 2 acute GvHD. This well-tolerated regimen appears to accelerate immune recovery and shorten the duration of early post-transplant immunodeficiency, thereby reducing susceptibility to viral infections. Rapid T-cell reconstitution, retention of NK-cells in the graft, and induction of low grade GvHD may also enhance the potential anti-cancer immune effect.

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Efficient MGMTP140K-Mediated In Vivo Selection and Chemoprotection of Long-Term Repopulating Cells in Nonhuman Primates Following Reduced Intensity Conditioning.

Blood ◽

10.1182/blood.v114.22.3572.3572 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3572-3572

Author(s):

Brian C Beard ◽

Grant D Trobridge ◽

Jeannine S McCune ◽

Hans-Peter Kiem

Keyword(s):

Nonhuman Primates ◽

Conditioning Regimen ◽

Reduced Intensity Conditioning ◽

Hematopoietic Stem ◽

In Vivo Selection ◽

Reduced Intensity Conditioning Regimen ◽

Hematopoietic Toxicity ◽

Reduced Intensity

Abstract Abstract 3572 Poster Board III-509 Strategies using gene-modified hematopoietic stem cells to treat various severe hematopoietic diseases, including but not limited to hemoglobinopathies, will likely require high levels of gene marking. Here we have established efficient and stable in vivo selection in nonhuman primates using methylguanine methyltransferase (MGMTP140K). In the macaque (Macaca nemestrina) we were able to increase pre-chemotherapy lentiviral gene marking levels of 11.3% in granulocytes and 15.3% in lymphocytes to a post-chemotherapy gene marking level of 76.9% in granulocytes and 49.0% in lymphocytes. Furthermore, stable increases in gene marking were also observed in red blood cells (RBCs) and platelets (PLTs) with a pre-chemotherapy gene marking level of 5.6% and 6.7%, respectively, and a post-chemotherapy gene marking level of 15.2% and 64.0%, respectively. Importantly, the chemotherapy regimen was well tolerated, and engraftment was polyclonal as determined by analyzing long-term repopulating clones by LAM-PCR. In order to minimize extra-hematopoietic toxicity we have began to test a more clinically applicable conditioning regimen in the macaque model. This reduced intensity conditioning regimen should allow treatment of patients with severe hematopoietic or infectious diseases, who may not tolerate a high dose conditioning regimen. We tested targeted busulfan for conditioning to provide sufficient myelosuppression and to facilitate engraftment of chemoprotected hematopoietic stem cells while minimizing extra-hematopoietic toxicity. Following conditioning with busulfan (4 mg/kg/day for 2 days) and infusion of gene modified cells (∼1.7 × 107 CD34-selected cells/kg), there was moderate cytopenia with ANC <500/mL for 7 days and thrombocytopenia with a nadir of 18,000/mL. Following stable hematopoietic recovery, we observed gene marking, determined by RT-PCR, in total white blood cells as a provirus copy number of 0.04 (∼4% gene marking) that, following a single cycle of O6BG (x2) and BCNU, rose to 0.16 (∼16% gene marking). Currently, gene marking has been stable for more than 9 months following chemotherapy. The treatment was well tolerated with only transient elevated liver enzymes following O6BG/BCNU treatment and no additional extra-hematopoietic toxicity has been observed. Clonality studies before and after in vivo selection is underway using a combination of LAM-PCR and a modified whole genome pyrosequencing approach. In summary, we have attained efficient and stable in vivo selection of long-term repopulating cells in nonhuman primates, and have extended this approach to use a reduced intensity conditioning regimen that should be well tolerated in patients with many hematopoietic diseases. Disclosures: No relevant conflicts of interest to declare.

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The Use of Bone Marrow Graft for Hematopoietic Stem Cell Transplantation From Matched Unrelated Donors After Reduced Intensity Conditioning Regimen Improves Survival : Analysis of the Societe Française De Greffe De Moelle Et De Therapie Cellulaire.

Blood ◽

10.1182/blood.v114.22.873.873 ◽

2009 ◽

Vol 114 (22) ◽

pp. 873-873

Author(s):

Andrea Toma ◽

Marie-Lorraine Balère-Appert ◽

Jean-Michel Boiron ◽

Pierre Bordigoni ◽

Gerard Socie ◽

...

Keyword(s):

Stem Cells ◽

Multivariate Analysis ◽

Acute Gvhd ◽

Chronic Gvhd ◽

Conditioning Regimen ◽

Reduced Intensity Conditioning ◽

Hematopoietic Stem ◽

Reduced Intensity Conditioning Regimen ◽

Unrelated Donors ◽

Grade Ii

Abstract Abstract 873 The use of peripheral blood stem cells (PBSC) for hematopoietic stem cell transplantation (HSCT) is associated with a higher risk of chronic graft versus host disease (GvHD) but its impact on survival is not clear since it may favor a greater graft versus leukemia (GvL) effect. However, in the context of HSCT from unrelated donors (UD), the balance between GvH and GvL may differ from the context of sibling donors and thus the use of PBSC may be deleterious. In this retrospective study, we analyzed 103 patients from the french registry who received a graft from an UD after a reduced intensity conditioning regimen (RIC) to evaluate the role of various parameters including the source of stem cells on the outcome. Seventy-one D/R pairs (69%) were 10/10 HLA match at the allelic level. Mismatches concerned 5, 6, 15, 2 and 7 D/R pairs for HLA-A, -B, -C, -DRB1 and -DQB1, respectively. The median age was 46 years (18-67). All patients had hematologic malignancies: AL (n=35), MM (n=18), CLL (n=5), NHL (n=11), HD (n=9), CML (n=12), MDS (n=9), and MPS (n=4). 39% of the patients were in an advanced phase of the disease at time of HSCT. The conditioning regimen was Fluda/TBI 2Gys for 26 patients, Bu/Fluda/ATG for 24 patients, Fluda/Melph for 16 patients and others for 37 patients. Overall, anti-thymocytes globulins (ATG) were part of the conditioning regimen for 77% of patients. The source of stem cells was PBSC for 65 patients and bone marrow (BM) for 38 patients. The median follow up of the cohort is 61,3 months (1,2-113,7). The results showed that 95% of patients engrafted. Five patients did not engraft (4 in the BM group and 1 in the PBSC group). Acute GvHD grade II to IV and grade III/IV occurred in 47% and 19% of patients, respectively. The risk of developing chronic GvHD was 49% at 2 years. Overall survival (OS) was 36% at five years. The median disease free survival (DFS) was 55 months among the 36 patients alive. We performed univariate and multivariate analysis of factors susceptible to impact on GvHD and survival. The multivariate analysis included the impact of HLA mismatch, disease status, diagnosis, source of stem cells, patient's and donor's ages. This multivariate analysis performed on the global population shows a trend towards an improved OS with the use of BM instead of PBSC. However, when focusing the multivariate analysis on the 71 patients transplanted with a 10/10 match donor, the most potent factor influencing the outcome is the use of BM which is associated with an improved OS (p=0.03) and DFS (p=0.02), less acute GvHD grade II-IV (p=0.05), or grade III/IV (p=0.05) and less chronic GvHD (p=0.05). These results suggest that the use of BM as the source of stem cells should be reconsidered in the context of matched UD after RIC transplantation. Disclosures: No relevant conflicts of interest to declare.

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