Outcome of pediatric chronic myeloid leukemia with management focusing on the monitoring of BCR-ABL fusion gene transcript levels.

Background and objective: Clinical, laboratory and outcome data were reviewed for pediatric patients who were diagnosed with chronic myeloid leukemia (CML) and managed at two tertiary care hospitals in Saudi Arabia, between January 2011 and December 2017 to assess the response to tyrosine kinase inhibitors (TKI) focusing on the monitoring of BCR-ABL fusion gene transcript levels and to look at the overall outcome. Methods: CML patients were identified based on the cytogenetic and molecular results. Results: Twelve pediatric patients diagnosed with CML at a median age of 8.4 year; treated with TKI as first-line therapy, 11 (91.7%) patients were started with imatinib (first-generation TKI), while one received dasatinib (second-generation TKI) due to his three-way Philadelphia chromosome sensitivity. Eight patients (72.7%) starting on imatinib were switched to dasatinib (six patients due to drug resistance, and two patients due to intolerance of Imatinib) and two patients (25%) of whom had already achieved major molecular response (MMR) on Imatinib. Response rate to imatinib in terms of achieving MMR as first-line therapy was achieved in five out of 11 patients (45.5%) and only three of them continued to maintain their MMR. Six out of eight patients who were switched to dasatinib achieved MMR. Two patients underwent hematopoietic stem cell transplant (SCT): one due to blast crisis and one due to the side effects of TKI. With a median follow-up time of 78 months (range, 40.5-108), all of our patients were alive at last update. Conclusion: We report an excellent outcome with an overall survival (OS) of 100% at 5-year and disease-free survival (DFS) of 91.7% (8.0%). All our patients achieved MMR and only one patient had loss of MMR on follow-up. Eight patients (66.7%) achieved complete molecular response (CMR).

Hematopoietic Stem Cell Transplantation Stabilizes Cerebral Vasculopathy in High-Risk Pediatric Sickle Cell Disease Patients: Evidence From a Referral Transplant Center.

Background: Severe sickle cell disease (SCD) can present with different vaso-occlusive manifestations with cerebral vasculopathy (CV) as one of the most serious complications. Hematopoietic stem cell transplant (HSCT) is the ultimate therapy for this complication. The aim of this study was to assess the outcome and impact of HSCT on severe SCD patients with CV complications. Methods: Twenty-five consecutive transplants-naive pediatric SCD patients with CV complications underwent HSCT at our institution between 1993 and 2015, using bone marrow as stem cells source from fully match related donors were included. Neurologic evaluation was done both clinically and radiologically before transplantation and regularly following the HSCT. Results: With a median follow-up of 52.2 ± 5.8 months, the cumulative probability of overall survival (OS) at 3 years was 92.0% and event-free survival (EFS) was 88%. Significant neurologic improvements were observed in most of the patients clinically. Different neurologic complications were assessed. The neurologic manifestations before and after HSCT were hemiparesis (11, 1), seizures (13, 8), focal neurologic deficit (4, 2), loss of conscious (2, 1) headache (6, 1), and psychological symptoms (5, 2). Post-HSCT radiological imaging was done in 15 patients, which showed stabilization of CV among all. Conclusions: Allogeneic HSCT in patients with severe SCD presenting with CV complications including moyamoya vasculopathy showed favorable outcome with significant clinical neurologic improvement and stabilization of the disease. None of the patients with severe vasculopathy underwent neurological vascular by-pass surgery prior to HSCT.

Umbilical Cord Blood Transplantation after Graft Failure from a Previous Hematopoietic Stem Cell Transplantation.

Graft failure (GF) is a life-threatening complication after allogeneic hematopoietic stem cell transplantation (HCT). In the absence of autologous recovery, a second HCT is necessary to attempt to prevent death due to prolonged pancytopenia. Previous studies describing outcomes of second HCT performed after GF with different types of donor sources report wide ranges of overall survival (OS) and transplantation-related mortality (TRM); however, studies including a large number of patients undergoing a second HCT with umbilical cord blood (UCB) as the graft source are scarce. This retrospective registry-based study examined data extracted from Eurocord and the European Society for Blood and Marrow Transplantation (EBMT) databases to evaluate outcomes of 247 UCBTs performed in EBMT transplant centers after GF following a previous HCT. Data were analyzed separately for patients with malignant diseases (n = 141) and those with nonmalignant diseases (n = 106). The most frequent HCT that resulted in GF was also UCBT (65.0% for patients with malignant diseases and 68.9% for those with nonmalignant diseases), and most GFs occurred within 100 days after transplantation (92.3% and 85.9%, respectively). The median follow-up was 47 months for surviving patients with malignant diseases and 38 months for those with nonmalignant diseases. We observed a similar cumulative incidence of neutrophil engraftment of 59.1% (95% confidence interval [CI], 51.4% to 67.9%) and 60.4% (95% CI, 51.7%-70.6%), respectively, at a median time of 23 days and 24 days, correspondingly. The 3-year OS was 28.9% (95% CI, 21.8% to 37.3%) in the malignant disease group and 49.1% (95% CI, 39.5%-58.8%) in the nonmalignant disease group. In patients with malignancies, TRM was 39.9% (95% CI, 32.5% to 49.1%) at 100 days and 57.5% (95% CI, 49.4%-66.8%) at 3 years. In multivariate analyses, none of the characteristics studied was statistically significantly associated with engraftment or OS. Although survival is not optimal in patients requiring a second HCT, UCBT remains a valid life-saving option for patients with GF.

Outcomes of Unmanipulated Haploidentical Transplantation Using Post-Transplant Cyclophosphamide (PT-Cy) in Pediatric Patients With Acute Lymphoblastic Leukemia.

HLA-haploidentical transplantation (haplo-HCT) using post-transplantation-cyclophosphamide (PT-Cy) is a feasible procedure in children with malignancies. However, large studies on Haplo-HCT with PT-Cy for childhood acute lymphoblastic leukemia (ALL) are lacking. We analyzed haplo-HCT outcomes in 180 children with ALL. Median age was 9 years, and median follow-up was 2.7 years. Disease status was CR1 for 24%, CR2 for 45%, CR+3 for 12%, and active disease for 19%. All patients received PT-Cy day +3 and +4. Bone marrow (BM) was the stem cell source in 115 patients (64%). Cumulative incidence of 42-day engraftment was 88.9%. Cumulative incidence of day-100 acute graft-versus-host disease (GVHD) grade II-IV was 28%, and 2-year chronic GVHD was 21.9%. At 2 years, cumulative incidence of nonrelapse mortality (NRM) was 19.6%. Cumulative incidence was 41.9% for relapse and 25% for patients in CR1. Estimated 2-year leukemia free survival was 65%, 44%, and 18.8% for patients transplanted in CR1, CR2, CR3+ and 3% at 1 year for active disease. In multivariable analysis for patients in CR1 and CR2, disease status (CR2 [hazard ratio {HR} = 2.19; P = .04]), age at HCT older than 13 (HR = 2.07; P = .03) and use of peripheral blood stem cell (PBSC) (HR = 1.98; P = .04) were independent factors associated with decreased overall survival. Use of PBSC was also associated with higher NRM (HR = 3.13; P = .04). Haplo-HCT with PT-Cy is an option for children with ALL, namely those transplanted in CR1 and CR2. Age and disease status remain the most important factors for outcomes. BM cells as a graft source is associated with improved survival.

Hematopoietic cell transplantation in chronic granulomatous disease: a study of 712 children and adults.

Chronic granulomatous disease (CGD) is a primary immunodeficiency resulting in life-threatening infections and inflammatory complications. Allogeneic hematopoietic cell transplantation (allo-HCT) can cure the disease, but the indication to transplant remains controversial. We performed a retrospective multicenter study of 712 patients with CGD who underwent allo-HCT transplantation from March 1993 through December 2018. We studied 635 children (aged <18 years) and 77 adults. Median follow-up was 45 months. Median age at transplantation was 7 years (range, 0.1-48.6). Kaplan-Meier estimates of overall survival (OS) and event-free survival (EFS) at 3 years were 85.7% and 75.8%, respectively. In multivariate analysis, older age was associated with reduced survival and increased chronic graft-versus-host disease. Nevertheless, OS and EFS at 3 years for patients ≥18 years were 76% and 69%, respectively. Use of 1-antigen-mismatched donors was associated with reduced OS and EFS . No significant difference was found in OS, but a significantly reduced EFS was noted in the small group of patients who received a transplant from a donor with a >1 antigen mismatch. Choice of conditioning regimen did not influence OS or EFS. In summary, we report an excellent outcome after allo-HCT in CGD, with low incidence of graft failure and mortality in all ages. Older patients and recipients of 1-antigen-mismatched grafts had a less favorable outcome. Transplantation should be strongly considered at a younger age and particularly in the presence of a well-matched donor.

Pulmonary Complications in Pediatric and Adolescent Patients Following Allogeneic Hematopoietic Cell Transplantation.

Pulmonary complications after hematopoietic cell transplantation (HCT) can lead to significant morbidity and mortality. Limited evaluation of the true incidence of these complications in children and subsequent outcomes of these complications have not been evaluated recently. In April 2018, the National Heart, Lung, and Blood Institute; the Eunice Kennedy Shriver National Institute of Child Health and Human Development; and the National Cancer Institute cosponsored a meeting of experts to describe the status of pulmonary complications in children after HCT, identify critical gaps in knowledge, and explore avenues for research to advance care and optimize outcomes. The Center for International Blood and Marrow Transplant Research was used to evaluate the cumulative incidence of pulmonary complications in children and their respective survival. Of the 5022 children included in this analysis who received allogeneic HCT from 2010 to 2016, 606 developed pulmonary complications within the first year after HCT. Pneumonitis occurred in 388 patients, 125 patients developed pulmonary hemorrhage, and 200 patients had lung graft-versus-host disease (GVHD). For those developing pulmonary complications within 1 year, overall survival 100 days after diagnosis of pulmonary complications was 49% (95% confidence interval [CI], 43% to 54%) for patients with pneumonitis, 23% (95% CI, 16% to 31%) in patients with pulmonary hemorrhage, and 87% (95% CI, 81% to 91%) in patients with pulmonary GVHD. This study demonstrates the approximate incidence of these complications, as well as their significant effects on survival, and can serve as a baseline for future research.

Graft Versus Host Disease Following HLA-Matched Sibling Donor Compared with Matched Related Donor for Hematopoietic Stem Cell Transplantation for the Treatment of Severe Combined Immunodeficiency Disease.

BACKGROUND: One of the limiting factors for successful hematopoietic stem cell transplantation (HSCT) is graft versus host disease (GVHD). The EBMT/ESID guidelines for HSCT in severe combined immunodeficiency (SCID) recommend no GVHD prophylaxis for a matched sibling donor (MSD). OBJECTIVE: To determine the risk of GVHD in MSD HSCT for SCID patients compared to matched related donor (MRD). METHODS: This retrospective cohort study compares MSD with MRD and the outcome of GVHD in all SCID patients who underwent HSCT between 1993 and 2013. All statistical analyses were done using IBM SPSS statistics software. RESULTS: One hundred forty-five SCID patients underwent 152 HSCTs while 82 (54%) received GVHD prophylaxis. GVHD occurred in 48 patients (31.5%); 20/48 (42%) had GVHD prophylaxis compared to 28/48 (58%) that did not, P = 0.022. Acute GVHD occurred at a higher trend in MSD, 37/120 (30.8%), compared to MRD, 6/32 (18.8%), P = 0.17. We also analyzed the outcome according to the period of HSCT. The first period was 1993 to 2003, 48 HSCTs, 43 MSD, 5 MRD; all patients had GVHD prophylaxis, and there was no difference in GVHD. The second period was 2004 to 2013: of 104 HSCTs, 77 had MSD and 27 had MRD; GVHD prophylaxis was used in 22.1% of MSD and 63% of MRD, P = 0.000. GVHD was significantly higher in the MSD (40.2%) compared to MRD (18.5%) patients, P = 0.041. CONCLUSION: GVHD prophylaxis in MSD transplant should be considered in SCID patients.

Early and late outcomes after cord blood transplantation for pediatric patients with inherited leukodystrophies.

Leukodystrophies (LD) are devastating inherited disorders leading to rapid neurological deterioration and premature death. Hematopoietic stem cell transplantation (HSCT) can halt disease progression for selected LD. Cord blood is a common donor source for transplantation of these patients because it is rapidly available and can be used without full HLA matching. However, precise recommendations allowing care providers to identify patients who benefit from HSCT are lacking. In this study, we define risk factors and describe the early and late outcomes of 169 patients with globoid cell leukodystrophy, X-linked adrenoleukodystrophy, and metachromatic leukodystrophy undergoing cord blood transplantation (CBT) at an European Society for Blood and Marrow Transplantation center or at Duke University Medical Center from 1996 to 2013. Factors associated with higher overall survival (OS) included presymptomatic status (77% vs 49%; P = .006), well-matched (≤1 HLA mismatch) CB units (71% vs 54%; P = .009), and performance status (PS) of >80 vs <60 or 60 to 80 (69% vs 32% and 55%, respectively; P = .003). For patients with PS≤60 (n = 20) or 60 to 80 (n = 24) pre-CBT, only 4 (9%) showed improvement. Of the survivors with PS >80 pre-CBT, 50% remained stable, 20% declined to 60 to 80, and 30% to <60. Overall, an encouraging OS was found for LD patients after CBT, especially for those who are presymptomatic before CBT and received adequately dosed grafts. Early identification and fast referral to a specialized center may lead to earlier treatment and, subsequently, to improved outcomes.

An Integrative Scoring System for Survival Prediction Following Umbilical Cord Blood Transplantation in Acute Leukemia.

Purpose: Survival of acute leukemia (AL) patients following umbilical cord blood transplantation (UCBT) is dependent on an array of individual features. Integrative models for risk assessment are lacking. We sought to develop a scoring system for prediction of overall survival (OS) and leukemia-free survival (LFS) at 2 years following UCBT in AL patients.Experimental Design: The study cohort included 3,140 pediatric and adult AL UCBT patients from the European Society of Blood and Marrow Transplantation and Eurocord registries. Patients received single or double cord blood units. The dataset was geographically split into a derivation (n = 2,362, 65%) and validation set (n = 778, 35%). Top predictors of OS were identified using the Random Survival Forest algorithm and introduced into a Cox regression model, which served for the construction of the UCBT risk score.Results: The score includes nine variables: disease status, diagnosis, cell dose, age, center experience, cytomegalovirus serostatus, degree of HLA mismatch, previous autograft, and anti-thymocyte globulin administration. Over the validation set an increasing score was associated with decreasing probabilities for 2 years OS and LFS, ranging from 70.21% [68.89-70.71, 95% confidence interval (CI)] and 64.76% (64.33-65.86, 95% CI) to 14.78% (10.91-17.41) and 18.11% (14.40-22.30), respectively. It stratified patients into six distinct risk groups. The score's discrimination (AUC) over multiple imputations of the validation set was 68.76 (68.19-69.04, range) and 65.78 (65.20-66.28) for 2 years OS and LFS, respectively.Conclusions: The UCBT score is a simple tool for risk stratification of AL patients undergoing UCBT. Widespread application of the score will require further independent validation. Clin Cancer Res; 23(21); 6478-86. ©2017 AACR.

Factors Determining the Outcome of Hematopoietic Stem Cell Transplantation in Patients With Acute Lymphoblastic Leukemia at King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia.

Medical records of 82 patients with acute lymphoblastic leukemia (ALL) who underwent hematopoietic cell transplantation (HCT) at our institution from 2005 to 2011 were reviewed. Forty-five patients were male (54.8%). The median age at HCT was 7.46 years (range, 0.98 to 14.31 y), the median time to HCT after diagnosis was 12.56 months. Ten patients were below the age of 1 year (12%). All patients were in complete remission at the time of HCT. In 83 transplants, 64 patients received HCT from human leukocyte antigen-identical-related donors and 19 from other donors. Stem cell source was bone marrow in 65 (78%) and cord blood in 18 (22%). Five-year overall survival was 58.8% and event-free survival was 54.3%. The cumulative incidence of acute graft versus host disease was 4.8%±2.3% and of chronic graft versus host disease was 8.9%±3.2%. The median time to absolute neutrophil count and platelet recovery was 17 days (range, 12 to 43 d) and 28 days (range, 15 to 98 d), respectively. One patient acquired CMV infection after transplant. No one developed venoocclusive disease, hemorrhagic cystitis, or other complication. Patient's age at diagnosis, sex, donor's human leukocyte antigen status and sex, source of transplant and complete remission status at HCT did not affect overall survival and event-free survival. Our results show a favorable outcome to HCT for acute lymphoblastic leukemia patients comparable to published data, and no single factor was associated with superior outcome.

Outcomes after Unrelated Umbilical Cord Blood Transplantation for Children with Osteopetrosis.

Hematopoietic stem cell transplantation (HSCT) is the only curative treatment for most children with osteopetrosis (OP). Timing of HSCT is critical; therefore, umbilical cord blood transplantation (UCBT) is an attractive option. We analyzed outcomes after UCBT in 51 OP children. Median age at UCBT was 6 months. Seventy-seven percent of the cord blood grafts had 0 or 1 HLA disparity with the recipient. Conditioning regimen was myeloablative (mostly busulfan-based in 84% and treosulfan-based in 10%). Antithymocyte globulin was given to 90% of patients. Median number of total nucleated and CD34+ cells infused was 14 × 107/kg and 3.4 × 105/kg, respectively. Median follow-up for survivors was 74 months. Cumulative incidence (CI) of neutrophil recovery was 67% with a median time to recovery of 23 days; 33% of patients had graft failure, 81% of engrafted patients had full donor engraftment, and 19% had mixed donor chimerism. Day 100 CI of acute graft-versus-host disease (grades II to IV) was 31% and 6-year CI of chronic graft-versus-host disease was 21%. Mechanical ventilation was required in 28%, and veno-occlusive disease was diagnosed in 16% of cases. Six-year overall survival rate was 46%. Comparative studies with other alternative donors should be performed to evaluate whether UCBT remains a valid alternative for children with OP without an HLA-matched donor.

Primary Immunodeficiency Diseases in Saudi Arabia: a Tertiary Care Hospital Experience over a Period of Three Years (2010-2013).

PURPOSE: Primary immunodeficiencies (PID) are a group of heterogeneous diseases. Epidemiological studies from databases worldwide show geographical variation. In this study the objective is to determine the spectrum of PID in Saudi Arabia by analyzing the database in a referral tertiary hospital. METHODS: This is a prospective data collection by interviews and medical chart review for all PID patients followed at the King Faisal Specialist Hospital & Research Center (KFSH&RC) from May 2010 to April 2013. RESULTS: A total of 502 patients presented (53 % male and 47 % female). Combined immunodeficiencies were the most common (59.7 %), followed by predominantly antibody deficiencies (12.3 %), congenital defects of phagocyte (9.4 %), combined immunodeficiencies with associated or syndromic features (6.2 %), disease of immune dysregulation (6 %), complement deficiencies (5.8), and defects in innate immunity (0.6 %). The most common combined immunodeficiencies phenotype was T-B-SCID (17 %). The patients' ages ranged from less than 1 year old to 78 years, and 394 patients (78.2 %) are in the paediatrics age group (<14 years). The overall mean age of symptoms onset was 17 months and the overall mean delay in diagnosis was 21.6 months. Recurrent infections were the most common occurring clinical presentation (66 %), followed by family history (26 %). Consanguinity was found in 75 % of the patients. A total of 308 (61 %) patients had undergone stem cell transplantation (SCT). CONCLUSION: The study revealed that combined immunodeficiencies are not uncommon and are the most frequent occurring diagnosis in our patient population. This study is a prerequisite to establish a national registry of primary immunodeficiency in Saudi Arabia.

Stem cell transplantation in severe congenital neutropenia: an analysis from the European Society for Blood and Marrow Transplantation.

Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative treatment of severe congenital neutropenia (SCN), but data on outcome are scarce. We report on the outcome of 136 SCN patients who underwent HSCT between 1990 and 2012 in European and Middle East centers. The 3-year overall survival (OS) was 82%, and transplant-related mortality (TRM) was 17%. In multivariate analysis, transplants performed under the age of 10 years, in recent years, and from HLA-matched related or unrelated donors were associated with a significantly better OS. Frequency of graft failure was 10%. Cumulative incidence (day +90) of acute graft-versus-host disease (GVHD) grade 2-4 was 21%. In multivariate analysis, HLA-matched related donor and prophylaxis with cyclosporine A and methotrexate were associated with lower occurrence of acute GVHD. Cumulative incidence (1 year) of chronic GVHD was 20%. No secondary malignancies occurred after a median follow-up of 4.6 years. These data show that the outcome of HSCT for SCN from HLA-matched donors, performed in recent years, in patients younger than 10 years is acceptable. Nevertheless, given the TRM, a careful selection of HSCT candidates should be undertaken.

Hematopoietic stem cell transplant for hyper-IgM syndrome due to CD40L defects: A single-center experience.

HIGMI is a disease with a high risk for morbidity and mortality. HSCT has been shown to be a curative option. This study retrospectively reviewed and analyzed data from five patients who received HSCT at King Faisal Specialist Hospital & Research Centre (KFSH&RC) in Riyadh, Saudi Arabia, between 2005 and 2013. Five patients with HIGMI syndrome underwent HSCT at a median age of 41 months (range, 9-72 months). The median time from diagnosis to transplantation was 30 months (range, 5-58 months). For all five patients, the donors were HLA-identical siblings. In three patients, the conditioning regimen was composed of BU and CY. Fludarabine and melphalan with either ATG or alemtuzumab was used in two patients. For GVHD prophylaxis, cyclosporine was used in two patients, and the combination of cyclosporine and MTX was used in three patients. The survival rate was 100%, with a median follow-up of 69 months (range, 13-100 months). All patients engrafted. Two patients developed acute GVHD. Four patients showed complete immune recovery with positive CD40L expression in activated T cells and discontinued IVIG replacement. HSCT in early stage from an HLA-matched sibling donor is potentially effective at curing the disease.

Hematopoietic stem cell transplantation for infantile osteopetrosis.

We report the international experience in outcomes after related and unrelated hematopoietic transplantation for infantile osteopetrosis in 193 patients. Thirty-four percent of transplants used grafts from HLA-matched siblings, 13% from HLA-mismatched relatives, 12% from HLA-matched, and 41% from HLA-mismatched unrelated donors. The median age at transplantation was 12 months. Busulfan and cyclophosphamide was the most common conditioning regimen. Long-term survival was higher after HLA-matched sibling compared to alternative donor transplantation. There were no differences in survival after HLA-mismatched related, HLA-matched unrelated, or mismatched unrelated donor transplantation. The 5- and 10-year probabilities of survival were 62% and 62% after HLA-matched sibling and 42% and 39% after alternative donor transplantation (P = .01 and P = .002, respectively). Graft failure was the most common cause of death, accounting for 50% of deaths after HLA-matched sibling and 43% of deaths after alternative donor transplantation. The day-28 incidence of neutrophil recovery was 66% after HLA-matched sibling and 61% after alternative donor transplantation (P = .49). The median age of surviving patients is 7 years. Of evaluable surviving patients, 70% are visually impaired; 10% have impaired hearing and gross motor delay. Nevertheless, 65% reported performance scores of 90 or 100, and in 17%, a score of 80 at last contact. Most survivors >5 years are attending mainstream or specialized schools. Rates of veno-occlusive disease and interstitial pneumonitis were high at 20%. Though allogeneic transplantation results in long-term survival with acceptable social function, strategies to lower graft failure and hepatic and pulmonary toxicity are urgently needed.

Factors affecting the outcome of related allogeneic hematopoietic cell transplantation in patients with Fanconi Anemia.

Hematopoietic cell transplantation (HCT) can cure bone marrow failure in patients with Fanconi Anemia (FA), and it is generally accepted that these patients should receive low-intensity conditioning because of the underlying DNA repair defect in their cells. Outcomes for recipients of matched related HCT have generally been favorable, but only a few studies have scrutinized the factors that may affect the eventual outcome of these patients. This retrospective analysis of 94 pediatric patients with FA who underwent related HCT at King Faisal Specialist Hospital & Research Center was carried out to attempt to identify factors that may affect outcome. Results showed overall survival (OS) probabilities of 92.5%, 89%, and 86% at 1, 5, and 10 years, respectively. In univariate analysis, use of higher dose cyclophosphamide (CY) (60 mg/kg) conditioning was associated with a better 10-year OS than lower dose CY (20 mg/kg) conditioning (91% versus 82%, respectively; P = .035), and use of radiation-containing regimens was associated with a significantly lower 10-year OS than nonradiation regimens (76% versus 91%, respectively; P = .005). Of the 4 regimens used in this study, the fludarabine-based regimen was associated with the highest survival (95.2%; P = .034). The use of the higher dose CY (60 mg/kg) was associated with a significantly increased incidence of hemorrhagic cystitis (HC) (20% versus 5.6% respectively; P = .049). Three patients (3%) developed squamous cell carcinoma (2 oropharyngeal and 1 genitourinary), at 9.4, 5.4, and 13.3 years after HCT; 2 of them had radiation-containing conditioning. In conclusion, our data suggest that although using a higher dose CY (60 mg/kg) conditioning regimen may be associated with better survival, it is also associated with a significantly increased risk of HC. The addition of fludarabine to the low-dose CY (20 mg/kg) is associated with the best survival. On the other hand, radiation-containing regimens are associated with significantly lower survival.

Avascular necrosis of bone after allogeneic hematopoietic cell transplantation in children and adolescents.

We conducted a nested case-control study within a cohort of 6244 patients to assess risk factors for avascular necrosis (AVN) of bone in children and adolescents after allogeneic transplantation. Eligible patients were ≤21 years of age, received their first allogeneic transplant between 1990 and 2008 in the United States, and had survived ≥ 6 months from transplantation. Overall, 160 patients with AVN and 478 control subjects matched by year of transplant, length of follow-up and transplant center were identified. Patients and control subjects were confirmed via central review of radiology, pathology, and/or surgical procedure reports. Median time from transplant to diagnosis of AVN was 14 months. On conditional logistic regression, increasing age at transplant (≥5 years), female gender, and chronic graft-versus-host disease (GVHD) were significantly associated with increased risks of AVN. Compared with patients receiving myeloablative regimens for malignant diseases, lower risks of AVN were seen in patients with nonmalignant diseases and those who had received reduced-intensity conditioning regimens for malignant diseases. Children at high risk for AVN include those within the age group where rapid bone growth occurs as well as those who experience exposure to myeloablative conditioning regimens and immunosuppression after hematopoietic cell transplantation for the treatment of GVHD. More research is needed to determine whether screening strategies specifically for patients at high risk for developing AVN with early interventions may mitigate the morbidity associated with this complication.