Key Points

  • Children with sickle cell disease engrafted unrelated donor marrow after reduced intensity conditioning.

  • A high incidence of GVHD and associated mortality compromised safety of the trial.

Abstract

Children with sickle cell disease experience organ damage, impaired quality of life, and premature mortality. Allogeneic bone marrow transplant from an HLA-matched sibling can halt disease progression but is limited by donor availability. A Blood and Marrow Transplant Clinical Trials Network (BMT CTN) phase 2 trial conducted from 2008 to 2014 enrolled 30 children aged 4 to 19 years; 29 were eligible for evaluation. The primary objective was 1-year event-free survival (EFS) after HLA allele-matched (at HLA-A, -B, -C, and -DRB1 loci) unrelated donor transplant. The conditioning regimen included alemtuzumab, fludarabine, and melphalan. Graft-versus-host disease (GVHD) prophylaxis included calcineurin inhibitor, short-course methotrexate, and methylprednisolone. Transplant indications included stroke (n = 12), transcranial Doppler velocity >200 cm/s (n = 2), ≥3 vaso-occlusive pain crises per year (n = 12), or ≥2 acute chest syndrome episodes (n = 4) in the 2 years preceding enrollment. Median follow-up was 26 months (range, 12-62 months); graft rejection was 10%. The 1- and 2-year EFS rates were 76% and 69%, respectively. The corresponding rates for overall survival were 86% and 79%. The day 100 incidence rate of grade II-IV acute GVHD was 28%, and the 1-year incidence rate of chronic GVHD was 62%; 38% classified as extensive. There were 7 GVHD-related deaths. A 34% incidence of posterior reversible encephalopathy syndrome was noted in the first 6 months. Although the 1-year EFS met the prespecified target of ≥75%, this regimen cannot be considered sufficiently safe for widespread adoption without modifications to achieve more effective GVHD prophylaxis. The BMT CTN #0601 trial was registered at www.clinicaltrials.gov as #NCT00745420.

Introduction

Sickle cell disease (SCD) is a monogenic hemoglobin disorder characterized by hemolytic anemia with variable clinical manifestations after endothelial damage and vasculopathy.1  Hypoperfusion results in multiple organ damage. In patients with severe disease, symptoms manifest early and progress during childhood. Allogeneic hematopoietic cell transplantation can replace sickle erythropoiesis. The results of HLA-matched sibling donor transplants are excellent, with event-free survival (EFS) in excess of 90% and with acceptable rates of graft rejection (GR) and graft-versus-host disease (GVHD).2-5  HLA-matched sibling donor transplants account for the majority of transplants performed worldwide for hemoglobinopathy.6,7  However, only 18% of patients with SCD have an HLA-matched sibling donor in the United States.8  HLA-matched adult unrelated donors (URDs) have been used to expand the donor pool for nonmalignant hematologic disorders, but their role in SCD transplants is unclear.9-11  Although the likelihood of finding an HLA-matched URD for African Americans is low at 16% to 19%, utilization of these donors does expand the donor pool.12  To date, most SCD transplants have used myeloablative conditioning regimens, but these can result in toxicities such as growth inhibition, gonadal hypofunction, and sterility.13-16  Reduced-intensity conditioning (RIC) regimens, although associated with a more favorable toxicity profile, can be associated with higher rates of GR, especially with graft sources such as umbilical cord blood.17-20  A RIC regimen augmented with host immunoablation by alemtuzumab was previously successful in achieving donor engraftment.21,22  In that report of HLA-matched sibling donor bone marrow transplant (BMT) in 52 children with hemoglobinopathies, acute and chronic GVHD rates were 23% and 13%, respectively.21  The regimen was adopted for a phase 2 URD transplant trial with bone marrow or umbilical cord blood grafts through the Blood and Marrow Transplant Clinical Trials Network (BMT CTN #0601; NCT 00745420). This report describes outcomes from the trial using bone marrow grafts. The umbilical cord blood arm was closed early after a high GR rate.19 

Methods

Study design

The primary end point was 1-year EFS; death from any cause, GR, or recurrent disease was considered an event. Prespecified secondary end points included overall survival, hematopoietic recovery, acute and chronic GVHD, infections, hepatic sinusoidal syndrome, interstitial pneumonitis, seizure, posterior reversible encephalopathy syndrome (PRES), and health-related quality of life (HRQL). The trial opened on 11 April 2008 and closed to enrollment on 24 April 2014. Enrollment was paused once for clarification of HLA typing requirements once (for 6 months) during this period. This analysis includes data collected as of March 2016. The median follow-up of surviving patients was 26 months (range, 12-62 months). All patients were followed for at least 24 months, except for 1 patient who was lost to follow-up at 12 months.

Patients

The protocol was approved by the institutional review board at each of the participating institutions. Informed consent was obtained from parents or from patients aged >18 years, and assent was obtained from patients aged 7-18 years before enrollment. The consent form extensively described alternate conservative treatment approaches for SCD, as well as the pros and cons of transplant. Trial eligibility was confirmed by 3 independent hematologists. Eligible patients were aged 3.0 to 20 years who had severe SCD indicated by 1 or more the following: (1) clinically significant neurologic event (stroke) or any neurologic defect lasting >24 hours and accompanied by an infarct on cerebral magnetic resonance imaging; (2) a transcranial Doppler velocity >200 cm/s by the nonimaging technique, or velocity that exceeded 185 cm/s by the imaging technique measured at a minimum of 2 separate occasions 1 month or more apart23 ; (3) a minimum of 2 episodes of acute chest syndrome within the preceding 2-year period and defined as new pulmonary alveolar consolidation involving at least 1 complete lung segment despite adequate supportive care measures; and (4) minimum of 3 new pain events per year in the previous 2 years and defined as new onset of pain lasting for at least 2 hours, for which there was no other explanation, and occurred despite adequate supportive care measures. Adequate organ function pretransplant required the following: serum creatinine levels <1.5 times the upper limit of normal for age and the glomerular filtration rate >100 mL/min per 1.73 m2 or adjusted for age; alanine aminotransferase and aspartate aminotransferase <5 times the upper limit of normal and direct serum bilirubin <2 times the upper limit of normal; left ventricular ejection fraction >40% or left ventricular shortening fraction >26%; and diffusing capacity of the lungs for carbon monoxide >40% of predicted (corrected for hemoglobin). Patients with serum ferritin >1000 ng/mL were required to have a liver biopsy demonstrating the absence of cirrhosis and bridging fibrosis if they had received regular red cell transfusions for >1 year. Hemoglobin S level was maintained at ≤45% within 7 days of initiation of transplant conditioning, and chelation and/or hydroxyurea were discontinued 48 hours before initiation of conditioning. Ineligible patients included those with an HLA-matched sibling, HIV seropositivity, a performance score <40, and uncontrolled bacterial, viral, or fungal infection.

Treatment

The conditioning regimen included alemtuzumab, fludarabine, and melphalan, with the alemtuzumab administered between day 22 and day 18 before graft infusion to achieve host immunoablation (Table 1). Prophylaxis for GVHD consisted of a calcineurin inhibitor (tacrolimus or cyclosporine) administered from day −3 through day 100 after graft infusion, with subsequent taper through day 180; methotrexate 7.5 mg/m2 on days 1, 3, and 6; and methylprednisolone 1 mg/kg per day from days 7 through 28, with subsequent taper by 20% per week. Supportive care recommendations included granulocyte colony-stimulating factor commenced on day 7 and continued until an absolute neutrophil count of 1.5 × 109/L on 3 days after the nadir, weekly surveillance for cytomegalovirus and Epstein-Barr virus reactivation, seizure prophylaxis for the duration of use of calcineurin inhibitors, strict blood pressure control, preemptive therapy for viral infections, bacterial prophylaxis through day 100, and prompt treatment of overt or suspected infections. To mitigate the risk of intracranial hemorrhage, platelet count was maintained at ≥50 × 109/L.24 

Table 1.

Treatment regimen

Day Treatment 
−23 Alemtuzumab test dose 3 mg IV* 
−22 Alemtuzumab 10 mg IV† 
−21 Alemtuzumab 15 mg IV† 
−20 Alemtuzumab 20 mg IV† 
−8 Fludarabine 30 mg/m2 IV 
−7 Fludarabine 30 mg/m2 IV 
−6 Fludarabine 30 mg/m2 IV 
−5 Fludarabine 30 mg/m2 IV 
−4 Fludarabine 30 mg/m2 IV 
−3 Melphalan 140 mg/m2 IV; cyclosporine or tacrolimus dosed to maintain appropriate levels through day 100, and then tapered to day 180 
−2 Rest 
−1 Rest 
Bone marrow infusion 
Methotrexate 7.5 mg/m2 IV 
Methotrexate 7.5 mg/m2 IV 
Methotrexate 7.5 mg/m2 IV 
Methylprednisolone 1 mg/kg per day IV through day 28, and then taper granulocyte colony-stimulating factor 5 μg/kg body weight per day IV until absolute neutrophil count is ≥0.5 × 109/L for 3 consecutive days 
Day Treatment 
−23 Alemtuzumab test dose 3 mg IV* 
−22 Alemtuzumab 10 mg IV† 
−21 Alemtuzumab 15 mg IV† 
−20 Alemtuzumab 20 mg IV† 
−8 Fludarabine 30 mg/m2 IV 
−7 Fludarabine 30 mg/m2 IV 
−6 Fludarabine 30 mg/m2 IV 
−5 Fludarabine 30 mg/m2 IV 
−4 Fludarabine 30 mg/m2 IV 
−3 Melphalan 140 mg/m2 IV; cyclosporine or tacrolimus dosed to maintain appropriate levels through day 100, and then tapered to day 180 
−2 Rest 
−1 Rest 
Bone marrow infusion 
Methotrexate 7.5 mg/m2 IV 
Methotrexate 7.5 mg/m2 IV 
Methotrexate 7.5 mg/m2 IV 
Methylprednisolone 1 mg/kg per day IV through day 28, and then taper granulocyte colony-stimulating factor 5 μg/kg body weight per day IV until absolute neutrophil count is ≥0.5 × 109/L for 3 consecutive days 
*

The test dose of alemtuzumab was administered 24 hours before the first dose, shown in this example on day −23.

Alemtuzumab treatment was required to be administered on 3 consecutive days but could begin on day −22, −21, or −20 and end on day −20, −19, or −18, respectively.

Outcomes

The primary end point was 1-year EFS. Primary or secondary GR or death was considered an event. Primary GR was defined as the presence of <20% donor cells as assessed by bone marrow or peripheral blood chimerism assays (any lineage) on or after day 42. Secondary GR was defined as the presence of <20% donor-derived hematopoietic cells in peripheral blood or bone marrow in a patient with prior evidence of >20% donor cells. The level was chosen based on absence of SCD symptoms, even when donor chimerism in blood or marrow approached 10%.21,25  Survival was defined as the time from transplant to death or last follow-up. Neutrophil recovery was defined as the first of 3 days when the absolute neutrophil count was ≥0.5 × 109/L. Platelet recovery was defined as the first of 7 days without a platelet transfusion that the platelet count was ≥50 × 109/L. Acute and chronic GVHD were graded by Seattle (ie, limited/extensive) and National Institutes of Health criteria (ie, mild/moderate/severe).26  Common Terminology Criteria for Adverse Events version 3.0 was used to report expected grade 3-5 adverse events. Major regimen-related toxicity (RRT) was defined as grade 4 or 5 in any organ system or grade 3 for pulmonary, cardiac, renal, central nervous system, oral, or mucosal.27  HRQL was assessed pretransplant (within 2 months of transplant), and thereafter on day 100, at 6 months, and at 1 year posttransplant using the Child Health Questionnaire (CHQ). The CHQ was chosen because it was the only HRQL measure that was validated and reliable for use in children with SCD at the time the study commenced.28,29  The CHQ-Parent Form 50 was used for parent reports, and the CHQ-Child Form 87 was used for the child self-report for children aged ≥10 years.

Statistical analysis

The primary hypothesis was that a RIC regimen would be sufficient for stable engraftment after HLA-matched URD BMT and result in 1-year EFS ≥75%. The sample size of 30 patients was chosen based on a 95% confidence interval (CI) length of 31. However, 1 patient was deemed ineligible after enrollment because the patient and donor were mismatched at 2 HLA-loci. Therefore the analysis includes 29 patients.

EFS and overall survival were calculated using the Kaplan-Meier estimator.30  The cumulative incidence method was used to estimate the incidence of events in the presence of competing risks for neutrophil and platelet recovery and acute and chronic GVHD; in each case, death was considered the competing risk.31  HRQL measurement was based on the CHQ Parent Form 50 (for patients 5-18 years old) and the CHQ Child Form 87 (for patients 10-18 years old). Mean scores for the CHQ were calculated based on a 4- to 6-point response scale for each item and transformed according to the developer’s instructions to a 0 to 100 scale, with a higher score representing a better quality of life.32  One domain, Change in Health, is composed of 1 question that is reported on a 1- to 5-point scale, with a higher number meaning better health. The impact of a change by >1 point is considered significant on a 5-category scale.33,34  HRQL data were analyzed for changes in mean HRQL score from pretransplant measurement and performed as an exploratory analysis, given the small sample size. A paired Student t test was used to assess changes from baseline to each posttransplant time point (day 100, 6 months, and 1 year). Only P values of <.01 were considered significant for the HRQL analyses, given the multiple comparisons. All analyses were performed using SAS version 9.3 (Cary, NC).

Results

Patient and donor characteristics

The characteristics of the donors and 29 patients who met eligibility criteria are shown in Table 2. All patients had a hemoglobin SS genotype. The median age at transplant was 14 years (range, 6-19 range), and 55% were male. Indications for transplant included stroke (41%), elevated transcranial Doppler velocity (7%), recurrent episodes of acute chest syndrome (14%), or significant pain (41%). Pretransplant, 26 patients had performance scores of 90 or 100, 2 patients had a score of 80, and the remaining patient had a score of 70. All patients had received erythrocyte transfusions before transplant. The median serum ferritin level was 722 ng/mL (range, 55-7324 ng/mL). Eight patients underwent liver biopsy for history of chronic red cell transfusions and a serum ferritin level of >1000 ng/mL, but no patient was excluded because none had evidence of bridging fibrosis or liver cirrhosis. The median hemoglobin S at transplant was 20.8% (range, 3.9%-43%). All 29 eligible patients received bone marrow grafts from an adult URD and were HLA matched at the allele-level at HLA-A, -B, -C, and -DRB1. One unrelated adult donor was a carrier with hemoglobin AS genotype. The median total nucleated cell dose of the bone marrow graft was 3.5 × 108/kg (range, 1.3 × 108/kg to 6.8 × 108/kg). The median CD34 dose of the graft was 2.9 × 106/kg (range, 0.3 × 106/kg to 9.2 × 106/kg).

Table 2.

Donor, recipient, and transplant characteristics

Characteristics 
Donor 
 Race/ethnicity  
  White 11 
  African American 11 
  Multiracial 
  Not reported 
Recipient†  
 Sex  
  Male 16 
  Female 13 
 Race/ethnicity  
  African American 26 
  Hispanic 
 Indications for transplant‡  
  Stroke 12 
  Transcranial Doppler velocity >200 cm/s 
  Acute chest syndrome 
  Vaso-occlusive pain crisis 12 
 Chronic blood transfusion before transplant 14 
 Performance score  
  100 17 
  90 
  80 
  70 
Transplant  
 CMV-seronegative donor and recipient 
 CMV-seropositive donor and recipient 
 CMV-seronegative donor and CMV-seropositive recipient 
 CMV-seropositive donor and CMV-seronegative recipient 
 ABO blood group matched 15 
 ABO blood group major mismatch 
 ABO blood group minor mismatch 
 Sex-matched transplants 15 
 Female donor, male recipient 
 Male donor, female recipient 
Characteristics 
Donor 
 Race/ethnicity  
  White 11 
  African American 11 
  Multiracial 
  Not reported 
Recipient†  
 Sex  
  Male 16 
  Female 13 
 Race/ethnicity  
  African American 26 
  Hispanic 
 Indications for transplant‡  
  Stroke 12 
  Transcranial Doppler velocity >200 cm/s 
  Acute chest syndrome 
  Vaso-occlusive pain crisis 12 
 Chronic blood transfusion before transplant 14 
 Performance score  
  100 17 
  90 
  80 
  70 
Transplant  
 CMV-seronegative donor and recipient 
 CMV-seropositive donor and recipient 
 CMV-seronegative donor and CMV-seropositive recipient 
 CMV-seropositive donor and CMV-seronegative recipient 
 ABO blood group matched 15 
 ABO blood group major mismatch 
 ABO blood group minor mismatch 
 Sex-matched transplants 15 
 Female donor, male recipient 
 Male donor, female recipient 

CMV, cytomegalovirus.

*

Median donor age was 35 years (range, 21-55 years).

Median recipient age was 14 years (range, 6-19 years).

Some patients had more than 1 indication.

EFS, overall survival, and engraftment

The primary end point was met. The 1-year EFS was 76% (95% CI, 56-88) and the 1-year overall survival was 86% (95% CI, 67-95). At data cutoff in March 2016, the 2-year EFS was 69% (95% CI, 48-82) and the 2-year overall survival was 79% (95% CI, 59-90) (Figure 1). Twenty-seven of 29 patients engrafted. The median time to neutrophil recovery was 12 days (range, 6-16 days) and the median time to platelet recovery was 24 days (range, 7-90 days), similar to published results using URDs.35  Two patients experienced primary GR (day 39 and day 91); 1 patient developed secondary GR on day 48 for a cumulative incidence of GR of 10%. All 3 patients experiencing GR recovered host hematopoiesis without marrow aplasia. Because mixed chimerism occurs frequently after transplant for SCD, we evaluated the percentage of donor cells at 3 months, at 1 year, and at 2 years.20,21,25  All engrafted patients demonstrated >90% donor chimerism at 3 months, and this persisted at the 1-year and 2-year time points in evaluable patients (n = 22 and n = 19 at 1 and 2 years, respectively). Hemoglobin S levels were undetectable in all but 1 patient who received a graft from an URD with sickle cell trait, and the hemoglobin S level was consequently 42%.

Figure 1.

Probability of EFS and overall survival. The 2-year probability of EFS (A) and overall survival (B) after URD transplant for severe SCD.

Figure 1.

Probability of EFS and overall survival. The 2-year probability of EFS (A) and overall survival (B) after URD transplant for severe SCD.

Although a RIC regimen was administered, RRT was implicated in 83% of grade 3-5 adverse events (63/76). Ten patients developed PRES with a 1-year incidence of 34% (95% CI, 18-52), resulting in reiteration of the importance of strict blood pressure control based on lower blood pressure norms established for SCD patients and of correcting any electrolyte imbalance. Two PRES events occurred before transplant. In the remaining 8 patients, calcineurin inhibitor was withdrawn. Thereafter, 1 patient received sirolimus, 2 received mycophenolate mofetil, and 5 received no alternate GVHD prophylaxis. Three patients developed renal failure and required dialysis. These events were transient, and all patients fully recovered.

Eight patients died after transplant. Seven patients, all aged ≥14 years, died of GVHD and related complications (Table 3). Five of the 7 patients had ferritin levels >1000 ng/mL, although none had fibrosis or cirrhosis. One patient with primary GR died of infection 3 months after a second myeloablative transplant. Four GVHD-related deaths occurred within the first year after transplant, whereas 3 occurred between 507 and 960 days.

Table 3.

Cause of death in 7 patients

Patient age, y Time of death, d Complications at the time of death 
17 231 Acute GVHD (gut); opportunistic infection; ARDS 
16 539 Chronic GVHD; CMV infection; encephalomyelitis; cardiorespiratory failure 
17 200 Acute GVHD (gut); respiratory and renal failure 
19 960 Chronic GVHD 
16 507 Chronic GVHD; VRE and HSV infections 
14 199 Acute GVHD; Candida and CMV infections; respiratory and renal failure 
18 143 Acute GVHD (gut); pulmonary hemorrhage; Staphylococcus aureus pneumonia 
Patient age, y Time of death, d Complications at the time of death 
17 231 Acute GVHD (gut); opportunistic infection; ARDS 
16 539 Chronic GVHD; CMV infection; encephalomyelitis; cardiorespiratory failure 
17 200 Acute GVHD (gut); respiratory and renal failure 
19 960 Chronic GVHD 
16 507 Chronic GVHD; VRE and HSV infections 
14 199 Acute GVHD; Candida and CMV infections; respiratory and renal failure 
18 143 Acute GVHD (gut); pulmonary hemorrhage; Staphylococcus aureus pneumonia 

ARDS, acute respiratory distress syndrome; CMV, cytomegalovirus; HSV, herpes simplex virus; VRE, vancomycin-resistant Enterococcus.

GVHD

The cumulative incidence on day 100 of grade II-IV acute GVHD was 28% (95% CI, 13-45), and was 17% (95% CI, 6-33) for grade III-IV acute GVHD (Figure 2A). The cumulative incidence of chronic GVHD at 1 year (Figure 2B) was 62% (95% CI, 41-77), with 38% classified as extensive. By National Institutes of Health scoring criteria, chronic GVHD was classified as mild in 6 patients, moderate in 8, and severe in 5. Of the 19 patients with sustained donor engraftment, 4 discontinued immune suppression by 1 year, 6 discontinued in the second year, and 5 discontinued after 2 years. Of the remaining 4 patients, 1 was weaning immune suppression when lost to follow-up at 1 year, 2 were weaning post-GVHD resolution, and 1 continued treatment of stable chronic GVHD. Performance scores at the 2-year or last follow-up visit were 100 in 13 patients, 90 in 5 patients, and 80 in 3 patients.

Figure 2.

Probability of GVHD. The 100-day probability of acute GVHD (A) and the 1-year probability of GVHD (B) after URD transplant for severe SCD.

Figure 2.

Probability of GVHD. The 100-day probability of acute GVHD (A) and the 1-year probability of GVHD (B) after URD transplant for severe SCD.

HRQL

SCD adversely affects quality of life, as previously reported.36  We were interested in learning whether HRQL improved after URD BMT in pediatric recipients. Validated measures for HRQL include change in health, physical functioning, behavior, and self-esteem. Parental proxies and patients who completed the forms, as indicated based on age, reported significant improvements in the change in health domain posttransplant (Table 4). Although initially, patients did not report any differences, parent proxies (n = 21) reported significantly worse Self-Esteem HRQL scores (mean change, −15.12; P = .006) but significantly better General Health Perception scores (mean change, 11.13; P = .0003) at day 100 compared with pretransplant baseline. The child-reported Change in Health score (n = 13) improved by a mean of 1.46 (P = .0013) at 12 months posttransplant compared with pretransplant scores. Parental proxies reported similar improvements at 6 and 12 months compared with pretransplant scores (mean change, 1.15 and 1.53, respectively; P < .01). The limited sample size precluded subanalyses such as assessing these changes in patients with and without chronic GVHD (see supplemental Table 1, available on the Blood Web site).

Table 4.

HRQL changes from pretransplant baseline to day 100, 6 months, and 1 year

HRQL score Day 100 6 Months 1 Year 
Mean (SEM) P Mean (SEM) P Mean (SEM)* P 
Parent proxy          
 Self-Esteem 21 −15.12 (4.89) .0057* 20 −11.46 (6.28) .0839 15 −3.61 (6.66) .5959 
 General Health Perception 21 11.13 (2.51) .0003* 20 7.63 (3.31) .0326 15 8.89 (5.27) .1135 
 Change in Health 21 0.90 (0.38) .0286 20 1.15 (0.36) .0052* 15 1.53 (0.48) .0062* 
Child          
 Self-Esteem 18 −0.59 (4.51) .8976 16 −4.33 (5.87) .4722 13 4.97 (5.33) .3691 
 General Health Perception 18 −1.90 (4.29) .6631 16 −6.69 (4.99) .2001 13 6.99 (6.35) .2927 
 Change in Health 18 0.33 (0.45) .4691 16 0.19 (0.52) .7225 13 1.46 (0.35) .0013* 
HRQL score Day 100 6 Months 1 Year 
Mean (SEM) P Mean (SEM) P Mean (SEM)* P 
Parent proxy          
 Self-Esteem 21 −15.12 (4.89) .0057* 20 −11.46 (6.28) .0839 15 −3.61 (6.66) .5959 
 General Health Perception 21 11.13 (2.51) .0003* 20 7.63 (3.31) .0326 15 8.89 (5.27) .1135 
 Change in Health 21 0.90 (0.38) .0286 20 1.15 (0.36) .0052* 15 1.53 (0.48) .0062* 
Child          
 Self-Esteem 18 −0.59 (4.51) .8976 16 −4.33 (5.87) .4722 13 4.97 (5.33) .3691 
 General Health Perception 18 −1.90 (4.29) .6631 16 −6.69 (4.99) .2001 13 6.99 (6.35) .2927 
 Change in Health 18 0.33 (0.45) .4691 16 0.19 (0.52) .7225 13 1.46 (0.35) .0013* 

Negative mean change denotes worsening HRQL score; positive mean change denotes improved HRQL score. Other items tested include the following (none of which reached the level of significance at any of the time points tested): physical functioning; social limitations due to emotional difficulties; social limitations due to behavioral difficulties; social limitations due to physical health; bodily pain and discomfort; behavioral; mental health; emotional impact; time impact; family activities; global health; global behavior; change in health; family cohesion; physical summary; and psychosocial summary.

SEM, standard error of the mean.

*

P values <.01 are statistically significant.

Discussion

Although EFS after HLA-matched sibling donor transplant is >90%, most patients do not have an HLA-matched sibling.4,5,21,37,38  This is the first multicenter URD transplant trial for SCD in North America and was conducted to expand access to transplantation utilizing HLA-matched URDs. The RIC regimen of alemtuzumab, melphalan, and fludarabine was used to overcome the higher risk of GR with URD BMT while limiting the toxicities associated with myeloablative regimens that may be exacerbated in patients with severe SCD and may limit patient acceptance.14,16,39,40 

Although the trial met the prespecified 1-year end point of 75% EFS, the 1-year chronic GVHD rate was higher than expected after HLA-matched URD BMT, and GVHD was the predominant cause of death, noted primarily in older patients. Reports in African Americans with severe aplastic anemia (combining sibling and URD transplants) suggest an overall chronic GVHD rate of 36% (95% CI, 24-48) compared with 30% noted in whites (P = .36), although extensive chronic GVHD was observed more commonly in African Americans than in whites (72% vs 49%; P = .06), as was GVHD-related mortality.41  Other than race, additional factors may have influenced the observed high rates of chronic GVHD in this trial. HLA matching at HLA-DPB1 loci was not considered in donor selection, and a mismatch at this locus increases the risk of acute GVHD.42-44  Another plausible explanation could be the timing of alemtuzumab administration 3 weeks before infusion of the graft (distal administration) to overcome host rejection of the graft. It was timed to achieve low alemtuzumab levels at the time of graft infusion to maximize donor T-cell engraftment, and thus did not have a significant effect as a GVHD prophylaxis agent.21  Chronic GVHD rates are also expected to be higher in URD BMT and increase with recipient age; the higher rates observed in this trial are consistent with less protection against chronic GVHD.45-47  Further, the protocol recommended calcineurin inhibitor taper early (after day 100) in the absence of GVHD and may have contributed to de novo chronic GVHD subsequently. Chronic GVHD developed in 8 of 10 patients after they developed PRES symptoms. The protocol did not specify alternate GVHD prophylaxis in the event of PRES, and treatment was left to the center’s choice. Because it is common practice to discontinue or modify calcineurin inhibitor use after PRES, it is possible that the withdrawal or modification of the calcineurin inhibitor after the development of PRES may have additionally contributed to GVHD. Alemtuzumab or anti-human T-lymphocyte immune globulin used just proximal to transplant can offer better protection against GVHD but predisposes to mixed chimerism and rejection.48-50  Novel preparative agents such as treosulfan and GVHD prophylaxis methods such as posttransplant cyclophosphamide have shown recent promise in transplantation for SCD.51,52 

HRQL improved significantly by 1 year posttransplant in the areas of Change in Health for these patients compared with pretransplant scores. Other HRQL domains did not show significant changes from baseline. The significant changes noted here, even in this small sample size, support that these children felt better and reported better functioning overall related to their health after transplant, despite the high incidence of chronic GVHD. We would expect patients with significant chronic GVHD after BMT to experience lower HRQL than those without, but the sample size was too small for a meaningful comparison between the two groups.

No patient developed hepatic sinusoidal syndrome or idiopathic pulmonary syndrome. However, one-third of the patients developed PRES (a known complication of SCD and hemoglobinopathy transplants) that was reversible, despite our recommendation for strict blood pressure monitoring and prompt intervention.53,54  Baseline blood pressure in SCD patients is generally lower than published norms for age, race, and sex, and the use of corticosteroid and calcineurin inhibitors may have exacerbated this complication. 53,55-57 

In conclusion, the trial met its prespecified 1-year EFS, and significantly improved HRQL was reported posttransplant. However, although the RIC provided successful engraftment in the majority of patients, the regimen cannot be considered safe for widespread adoption without modification due to the RRT and high rate of chronic GVHD, which was the predominant cause of mortality. Future trials on URD transplantation for SCD should focus on strategies that minimize risks of GVHD and include stopping rules for chronic GVHD.

The online version of this article contains a data supplement.

The publication costs of this article were defrayed in part by page charge payment. Therefore, and solely to indicate this fact, this article is hereby marked “advertisement” in accordance with 18 USC section 1734.

Acknowledgments

The Blood and Marrow Transplant Clinical Trials Network and the BMT CTN #0601 investigators gratefully acknowledge the contributions of the members of the External Review Committee: George Buchanan, University of Texas South Western, Dallas, TX; James Eckman, Emory University, Atlanta, GA; Alexis A. Thompson, Northwestern University Fienberg School of Medicine, Chicago, IL; and Catherine Wu, Dana Farber Cancer Institute, Boston, MA.

This work was supported by a grant from the National Institutes of Health, National Heart, Lung, and Blood Institute and National Cancer Institute (U10-HL069294) to the Blood and Marrow Transplant Clinical Trials Network, the National Marrow Donor Program, the Sickle Cell Disease Clinical Research Network, the National Center on Minority Health and Health Disparities, and the Pediatric Blood and Marrow Transplant Consortium.

The content is solely the responsibility of the authors and does not necessarily represent the official views of the above-mentioned parties.

Authorship

Contribution: S.S., M.E., J.A.P., B.R.L., M.M.H., M.C.W., and N.K. designed the trial, interpreted the data, and drafted the manuscript; S.S., N.K., J.E.L., M.C.W., and M.E. adjudicated primary and secondary end points; J.W. prepared the data set and analyzed the data; J.A.P. and B.R.L. prepared and analyzed the HRQL data; all remaining authors critically reviewed the manuscript; and all authors approved the final manuscript.

Conflict-of-interest disclosure: The authors declare no competing financial interests.

Correspondence: Shalini Shenoy, Department of Pediatrics, Washington University School of Medicine, Box 8116, 660 S. Euclid Ave, St. Louis, MO 63110; e-mail: shenoy@wustl.edu.

References

References
1.
Owusu-Ansah
A
,
Ihunnah
CA
,
Walker
AL
,
Ofori-Acquah
SF
.
Inflammatory targets of therapy in sickle cell disease
.
Transl Res
.
2016
;
167
(
1
):
281
-
297
.
2.
Walters
MC
,
Patience
M
,
Leisenring
W
, et al
.
Bone marrow transplantation for sickle cell disease
.
N Engl J Med
.
1996
;
335
(
6
):
369
-
376
.
3.
Panepinto
JA
,
Walters
MC
,
Carreras
J
, et al. 
;
Non-Malignant Marrow Disorders Working Committee, Center for International Blood and Marrow Transplant Research
.
Matched-related donor transplantation for sickle cell disease: report from the Center for International Blood and Transplant Research
.
Br J Haematol
.
2007
;
137
(
5
):
479
-
485
.
4.
Locatelli
F
,
Kabbara
N
,
Ruggeri
A
, et al. 
;
Eurocord and European Blood and Marrow Transplantation (EBMT) group
.
Outcome of patients with hemoglobinopathies given either cord blood or bone marrow transplantation from an HLA-identical sibling
.
Blood
.
2013
;
122
(
6
):
1072
-
1078
.
5.
Bernaudin
F
,
Socie
G
,
Kuentz
M
, et al. 
;
SFGM-TC
.
Long-term results of related myeloablative stem-cell transplantation to cure sickle cell disease
.
Blood
.
2007
;
110
(
7
):
2749
-
2756
.
6.
Arnold
SD
,
Bhatia
M
,
Horan
J
,
Krishnamurti
L
.
Haematopoietic stem cell transplantation for sickle cell disease - current practice and new approaches
.
Br J Haematol
.
2016
;
174
(
4
):
515
-
525
.
7.
Baronciani
D
,
Angelucci
E
,
Potschger
U
, et al
.
Hemopoietic stem cell transplantation in thalassemia: a report from the European Society for Blood and Bone Marrow Transplantation Hemoglobinopathy Registry, 2000-2010
.
Bone Marrow Transplant
.
2016
;
51
(
4
):
536
-
541
.
8.
Mentzer
WC
,
Heller
S
,
Pearle
PR
,
Hackney
E
,
Vichinsky
E
.
Availability of related donors for bone marrow transplantation in sickle cell anemia
.
Am J Pediatr Hematol Oncol
.
1994
;
16
(
1
):
27
-
29
.
9.
Peters
C
,
Balthazor
M
,
Shapiro
EG
, et al
.
Outcome of unrelated donor bone marrow transplantation in 40 children with Hurler syndrome
.
Blood
.
1996
;
87
(
11
):
4894
-
4902
.
10.
Deeg
HJ
,
O’Donnell
M
,
Tolar
J
, et al
.
Optimization of conditioning for marrow transplantation from unrelated donors for patients with aplastic anemia after failure of immunosuppressive therapy
.
Blood
.
2006
;
108
(
5
):
1485
-
1491
.
11.
Ruggeri
A
,
Eapen
M
,
Scaravadou
A
, et al. 
;
Eurocord Registry; Center for International Blood and Marrow Transplant Research; New York Blood Center
.
Umbilical cord blood transplantation for children with thalassemia and sickle cell disease
.
Biol Blood Marrow Transplant
.
2011
;
17
(
9
):
1375
-
1382
.
12.
Gragert
L
,
Eapen
M
,
Williams
E
, et al
.
HLA match likelihoods for hematopoietic stem-cell grafts in the U.S. registry
.
N Engl J Med
.
2014
;
371
(
4
):
339
-
348
.
13.
Fitzhugh
CD
,
Perl
S
,
Hsieh
MM
.
Late effects of myeloablative bone marrow transplantation (BMT) in sickle cell disease (SCD)
.
Blood
.
2008
;
111
(
3
):
1742
-
1743, author reply 1744
.
14.
Walters
MC
,
Hardy
K
,
Edwards
S
, et al. 
;
Multicenter Study of Bone Marrow Transplantation for Sickle Cell Disease
.
Pulmonary, gonadal, and central nervous system status after bone marrow transplantation for sickle cell disease
.
Biol Blood Marrow Transplant
.
2010
;
16
(
2
):
263
-
272
.
15.
Jagasia
M
,
Arora
M
,
Flowers
ME
, et al
.
Risk factors for acute GVHD and survival after hematopoietic cell transplantation
.
Blood
.
2012
;
119
(
1
):
296
-
307
.
16.
Eggleston
B
,
Patience
M
,
Edwards
S
, et al. 
;
Multicenter Study of HCT for SCA
.
Effect of myeloablative bone marrow transplantation on growth in children with sickle cell anaemia: results of the multicenter study of haematopoietic cell transplantation for sickle cell anaemia
.
Br J Haematol
.
2007
;
136
(
4
):
673
-
676
.
17.
Iannone
R
,
Casella
JF
,
Fuchs
EJ
, et al
.
Results of minimally toxic nonmyeloablative transplantation in patients with sickle cell anemia and beta-thalassemia
.
Biol Blood Marrow Transplant
.
2003
;
9
(
8
):
519
-
528
.
18.
Horan
JT
,
Liesveld
JL
,
Fenton
P
,
Blumberg
N
,
Walters
MC
.
Hematopoietic stem cell transplantation for multiply transfused patients with sickle cell disease and thalassemia after low-dose total body irradiation, fludarabine, and rabbit anti-thymocyte globulin
.
Bone Marrow Transplant
.
2005
;
35
(
2
):
171
-
177
.
19.
Kamani
NR
,
Walters
MC
,
Carter
S
, et al
.
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)
.
Biol Blood Marrow Transplant
.
2012
;
18
(
8
):
1265
-
1272
.
20.
Hsieh
MM
,
Fitzhugh
CD
,
Weitzel
RP
, et al
.
Nonmyeloablative HLA-matched sibling allogeneic hematopoietic stem cell transplantation for severe sickle cell phenotype
.
JAMA
.
2014
;
312
(
1
):
48
-
56
.
21.
King
AA
,
Kamani
N
,
Bunin
N
, et al
.
Successful matched sibling donor marrow transplantation following reduced intensity conditioning in children with hemoglobinopathies
.
Am J Hematol
.
2015
;
90
(
12
):
1093
-
1098
.
22.
Matthes-Martin
S
,
Lawitschka
A
,
Fritsch
G
, et al
.
Stem cell transplantation after reduced-intensity conditioning for sickle cell disease
.
Eur J Haematol
.
2013
;
90
(
4
):
308
-
312
.
23.
Nichols
FT
,
Jones
AM
,
Adams
RJ
.
Stroke prevention in sickle cell disease (STOP) study guidelines for transcranial Doppler testing
.
J Neuroimaging
.
2001
;
11
(
4
):
354
-
362
.
24.
Walters
MC
,
Sullivan
KM
,
Bernaudin
F
, et al
.
Neurologic complications after allogeneic marrow transplantation for sickle cell anemia
.
Blood
.
1995
;
85
(
4
):
879
-
884
.
25.
Walters
MC
,
Patience
M
,
Leisenring
W
, et al. 
;
Multicenter Investigation of Bone Marrow Transplantation for Sickle Cell Disease
.
Stable mixed hematopoietic chimerism after bone marrow transplantation for sickle cell anemia
.
Biol Blood Marrow Transplant
.
2001
;
7
(
12
):
665
-
673
.
27.
Bearman
SI
,
Appelbaum
FR
,
Buckner
CD
, et al
.
Regimen-related toxicity in patients undergoing bone marrow transplantation
.
J Clin Oncol
.
1988
;
6
(
10
):
1562
-
1568
.
28.
Palermo
TM
,
Schwartz
L
,
Drotar
D
,
McGowan
K
.
Parental report of health-related quality of life in children with sickle cell disease
.
J Behav Med
.
2002
;
25
(
3
):
269
-
283
.
29.
Panepinto
JA
,
O’Mahar
KM
,
DeBaun
MR
,
Rennie
KM
,
Scott
JP
.
Validity of the child health questionnaire for use in children with sickle cell disease
.
J Pediatr Hematol Oncol
.
2004
;
26
(
9
):
574
-
578
.
30.
Kaplan
EL
.
Meier P. Nonparametric estimation for incomplete observations
.
J Am Stat Assoc
.
1958
;
53(282)
457
-
481
.
31.
Gooley
TA
,
Leisenring
W
,
Crowley
J
,
Storer
BE
.
Estimation of failure probabilities in the presence of competing risks: new representations of old estimators
.
Stat Med
.
1999
;
18
(
6
):
695
-
706
.
32.
Landgraf
JM
,
Abetz
L
,
Ware
JE
.
The CHQ User’s Manual
.
Boston, MA
:
Health Act
;
1999
.
33.
Hays
RD
,
Farivar
SS
,
Liu
H
.
Approaches and recommendations for estimating minimally important differences for health-related quality of life measures
.
COPD
.
2005
;
2
(
1
):
63
-
67
.
34.
Beverung
LM
,
Strouse
JJ
,
Hulbert
ML
, et al. 
;
SIT trial investigators
.
Health-related quality of life in children with sickle cell anemia: impact of blood transfusion therapy
.
Am J Hematol
.
2015
;
90
(
2
):
139
-
143
.
35.
Bernardo
ME
,
Piras
E
,
Vacca
A
, et al
.
Allogeneic hematopoietic stem cell transplantation in thalassemia major: results of a reduced-toxicity conditioning regimen based on the use of treosulfan
.
Blood
.
2012
;
120
(
2
):
473
-
476
.
36.
Panepinto
JA
,
O’Mahar
KM
,
DeBaun
MR
,
Loberiza
FR
,
Scott
JP
.
Health-related quality of life in children with sickle cell disease: child and parent perception
.
Br J Haematol
.
2005
;
130
(
3
):
437
-
444
.
37.
Walters
MC
,
Patience
M
,
Leisenring
W
, et al
.
Barriers to bone marrow transplantation for sickle cell anemia
.
Biol Blood Marrow Transplant
.
1996
;
2
(
2
):
100
-
104
.
38.
Besse
K
,
Maiers
M
,
Confer
D
,
Albrecht
M
.
On Modeling Human Leukocyte Antigen-Identical Sibling Match Probability for Allogeneic Hematopoietic Cell Transplantation: Estimating the Need for an Unrelated Donor Source
.
Biol Blood Marrow Transplant
.
2016
;
22
(
3
):
410
-
417
.
39.
Hingorani
SR
,
Seidel
K
,
Lindner
A
,
Aneja
T
,
Schoch
G
,
McDonald
G
.
Albuminuria in hematopoietic cell transplantation patients: prevalence, clinical associations, and impact on survival
.
Biol Blood Marrow Transplant
.
2008
;
14
(
12
):
1365
-
1372
.
40.
Maradei
SC
,
Maiolino
A
,
de Azevedo
AM
,
Colares
M
,
Bouzas
LF
,
Nucci
M
.
Serum ferritin as risk factor for sinusoidal obstruction syndrome of the liver in patients undergoing hematopoietic stem cell transplantation
.
Blood
.
2009
;
114
(
6
):
1270
-
1275
.
41.
Eckrich
MJ
,
Ahn
KW
,
Champlin
RE
, et al
.
Effect of race on outcomes after allogeneic hematopoietic cell transplantation for severe aplastic anemia
.
Am J Hematol
.
2014
;
89
(
2
):
125
-
129
.
42.
Pidala
J
,
Lee
SJ
,
Ahn
KW
, et al
.
Nonpermissive HLA-DPB1 mismatch increases mortality after myeloablative unrelated allogeneic hematopoietic cell transplantation
.
Blood
.
2014
;
124
(
16
):
2596
-
2606
.
43.
Morishima
Y
,
Kashiwase
K
,
Matsuo
K
, et al. 
;
Japan Marrow Donor Program
.
Biological significance of HLA locus matching in unrelated donor bone marrow transplantation
.
Blood
.
2015
;
125
(
7
):
1189
-
1197
.
44.
Fleischhauer
K
,
Locatelli
F
,
Zecca
M
, et al
.
Graft rejection after unrelated donor hematopoietic stem cell transplantation for thalassemia is associated with nonpermissive HLA-DPB1 disparity in host-versus-graft direction
.
Blood
.
2006
;
107
(
7
):
2984
-
2992
.
45.
Morishima
S
,
Kashiwase
K
,
Matsuo
K
, et al. 
;
Japan Marrow Donor Program
.
High-risk HLA alleles for severe acute graft-versus-host disease and mortality in unrelated donor bone marrow transplantation
.
Haematologica
.
2016
;
101
(
4
):
491
-
498
.
46.
Zhang
MJ
,
Davies
SM
,
Camitta
BM
, et al
.
Comparison of outcomes after HLA-matched sibling and unrelated donor transplantation for children with high-risk acute lymphoblastic leukemia
.
Biol Blood Marrow Transplant
.
2012
;
18
(
8
):
1204
-
1210
.
47.
Weisdorf
DJ
,
Nelson
G
,
Lee
SJ
, et al. 
;
Chronic Leukemia Working Committee
.
Sibling versus unrelated donor allogeneic hematopoietic cell transplantation for chronic myelogenous leukemia: refined HLA matching reveals more graft-versus-host disease but not less relapse
.
Biol Blood Marrow Transplant
.
2009
;
15
(
11
):
1475
-
1478
.
48.
Marsh
JCGV
,
Gupta
V
,
Lim
Z
, et al
.
Alemtuzumab with fludarabine and cyclophosphamide reduces chronic graft-versus-host disease after allogeneic stem cell transplantation for acquired aplastic anemia
.
Blood
.
2011
;
118
(
8
):
2351
-
2357
.
49.
Kröger
N
,
Solano
C
,
Wolschke
C
, et al
.
Antilymphocyte globulin for prevention of chronic graft-versus-host disease
.
N Engl J Med
.
2016
;
374
(
1
):
43
-
53
.
50.
Lindemans
CA
,
Chiesa
R
,
Amrolia
PJ
, et al
.
Impact of thymoglobulin prior to pediatric unrelated umbilical cord blood transplantation on immune reconstitution and clinical outcome
.
Blood
.
2014
;
123
(
1
):
126
-
132
.
51.
Bolaños-Meade
J
,
Fuchs
EJ
,
Luznik
L
, et al
.
HLA-haploidentical bone marrow transplantation with posttransplant cyclophosphamide expands the donor pool for patients with sickle cell disease
.
Blood
.
2012
;
120
(
22
):
4285
-
4291
.
52.
Strocchio
L
,
Zecca
M
,
Comoli
P
, et al
.
Treosulfan-based conditioning regimen for allogeneic haematopoietic stem cell transplantation in children with sickle cell disease
.
Br J Haematol
.
2015
;
169
(
5
):
726
-
736
.
53.
Erer
B
,
Polchi
P
,
Lucarelli
G
, et al
.
CsA-associated neurotoxicity and ineffective prophylaxis with clonazepam in patients transplanted for thalassemia major: analysis of risk factors
.
Bone Marrow Transplant
.
1996
;
18
(
1
):
157
-
162
.
54.
Khademian
Z
,
Speller-Brown
B
,
Nouraie
SM
,
Minniti
CP
.
Reversible posterior leuko-encephalopathy in children with sickle cell disease
.
Pediatr Blood Cancer
.
2009
;
52
(
3
):
373
-
375
.
55.
Pegelow
CH
,
Colangelo
L
,
Steinberg
M
, et al
.
Natural history of blood pressure in sickle cell disease: risks for stroke and death associated with relative hypertension in sickle cell anemia
.
Am J Med
.
1997
;
102
(
2
):
171
-
177
.
56.
Noè
A
,
Cappelli
B
,
Biffi
A
, et al
.
High incidence of severe cyclosporine neurotoxicity in children affected by haemoglobinopaties undergoing myeloablative haematopoietic stem cell transplantation: early diagnosis and prompt intervention ameliorates neurological outcome
.
Ital J Pediatr
.
2010
;
36
14
.
57.
Hammerstrom
AE
,
Howell
J
,
Gulbis
A
,
Rondon
G
,
Champlin
RE
,
Popat
U
.
Tacrolimus-associated posterior reversible encephalopathy syndrome in hematopoietic allogeneic stem cell transplantation
.
Am J Hematol
.
2013
;
88
(
4
):
301
-
305
.