Zhaoyu Luo

Impact of hydroxyurea on clinical events in the BABY HUG trial

The Pediatric Hydroxyurea Phase 3 Clinical Trial (BABY HUG) was a phase 3 multicenter, randomized, double-blind, placebo-controlled clinical trial of hydroxyurea in infants (beginning at 9-18 months of age) with sickle cell anemia. An important secondary objective of this study was to compare clinical events between the hydroxyurea and placebo groups. One hundred and ninety-three subjects were randomized to hydroxyurea (20 mg/kg/d) or placebo; there were 374 patient-years of on-study observation. Hydroxyurea was associated with statistically significantly lower rates of initial and recurrent episodes of pain, dactylitis, acute chest syndrome, and hospitalization; even infants who were asymptomatic at enrollment had less dactylitis as well as fewer hospitalizations and transfusions if treated with hydroxyurea. Despite expected mild myelosuppression, hydroxyurea was not associated with an increased risk of bacteremia or serious infection. These data provide important safety and efficacy information for clinicians considering hydroxyurea therapy for very young children with sickle cell anemia. This clinical trial is registered with the National Institutes of Health (NCT00006400, www.clinicaltrials.gov).

HIV infection is associated with reduced pulmonary diffusing capacity

Introduction:Prior studies comparing abnormalities in pulmonary function between HIV-infected and HIV-uninfected persons in the current era are limited. Objectives:To determine the pattern and severity of impairment in pulmonary function in HIV-infected compared with HIV-uninfected individuals. Methods:Cross-sectional analysis of 300 HIV-infected men and 289 HIV-uninfected men enrolled from 2009 to 2011 in 2 clinical centers of the Lung HIV Study. Participants completed pre- and postbronchodilator spirometry, diffusing capacity of the lung for carbon monoxide (DLCO) measurement, and standardized questionnaires. Results:Most participants had normal airflow; 18% of HIV-infected and 16% of HIV-uninfected men had airflow obstruction. The mean percent predicted DLCO was 69% in HIV-infected vs. 76% in HIV-uninfected men (P < 0.001). A moderately to severely reduced DLCO of ⩽60% was observed in 30% of HIV-infected compared with 18% of HIV-uninfected men (P < 0.001), despite the fact that 89% of those with HIV were on antiretroviral therapy. A reduced DLCO was significantly associated with HIV and CD4 cell count in linear regression adjusting for smoking and other confounders. The DLCO was lowest in HIV-infected men with CD4 cell counts <200 cells per microliter compared with those with CD4 cell counts ≥200 cells per microliter and to HIV-uninfected men. Respiratory symptoms of cough, phlegm and dyspnea were more prevalent in HIV-infected patients particularly those with abnormal pulmonary function compared with HIV-uninfected patients. Conclusions:HIV infection is an independent risk factor for reduced DLCO, particularly in individuals with a CD4 cell count below 200 cells per microliter. Abnormalities in pulmonary function among HIV-infected patients manifest clinically with increased respiratory symptoms. Mechanisms accounting for the reduced DLCO require further evaluation.

Genetic modifiers of sickle cell anemia in the BABY HUG cohort: influence on laboratory and clinical phenotypes.

The recently completed BABY HUG trial investigated the safety and efficacy of hydroxyurea in infants with sickle cell anemia (SCA). To investigate the effects of known genetic modifiers, genomic DNA on 190 randomized subjects were analyzed for alpha thalassemia, beta‐globin haplotype, polymorphisms affecting endogenous fetal hemoglobin (HbF) levels (XmnI, BCL11A, and HBS1L‐MYB), UGT1A1 promoter polymorphisms, and the common G6PD A− mutation. At study entry, infants with alpha thalassemia trait had significantly lower mean corpuscular volume, total bilirubin, and absolute reticulocyte count. Beta‐globin haplotypes associated with milder disease had significantly higher hemoglobin and %HbF. BCL11A and XmnI polymorphisms had significant effects on baseline HbF, while UGT1A1 promoter polymorphisms significantly influenced baseline serum bilirubin. At study exit, subjects randomized to placebo still exhibited laboratory effects of alpha thalassemia and other modifiers, while those assigned hydroxyurea had treatment effects that exceeded most genetic influences. The pain phenotype was influenced by HbF modifiers in both treatment groups. These data document that genetic polymorphisms do modify laboratory and clinical phenotypes even in very young patients with SCA. The hydroxyurea effects are more potent, however, indicating that treatment criteria should not be limited to certain genetic subsets, and supporting the use of hydroxyurea for all young patients with SCA. Am. J. Hematol. 88:571–576, 2013.

Biomarkers of splenic function in infants with sickle cell anemia: baseline data from the BABY HUG trial

We evaluated spleen function in 193 children with sickle cell anemia 8 to 18 months of age by (99m)Tc sulfur-colloid liver-spleen scan and correlated results with clinical and laboratory parameters, including 2 splenic biomarkers: pitted cell counts (PIT) and quantitative Howell-Jolly bodies (HJB) enumerated by flow cytometry. Loss of splenic function began before 12 months of age in 86% of infants in association with lower total or fetal hemoglobin and higher white blood cell or reticulocyte counts, reinforcing the need for early diagnosis and diligent preventive care. PIT and HJB correlated well with each other and liver-spleen scan results. Previously described biomarker threshold values did define patients with abnormal splenic function, but our data suggest that normal spleen function is better predicted by PIT of ≤1.2% or HJB ≤55/10(6) red blood cells and absent function by PIT ≥4.5% or HJB ≥665/10(6). HJB is methodologically advantageous compared with PIT, but both are valid biomarkers of splenic function. This trial was registered at www.clinicaltrials.gov as #NCT00006400.

Effect of hydroxyurea treatment on renal function parameters: Results from the multi-center placebo-controlled BABY HUG clinical trial for infants with sickle cell anemia

Children with sickle cell anemia (SCA) often develop hyposthenuria and renal hyperfiltration at an early age, possibly contributing to the glomerular injury and renal insufficiency commonly seen later in life. The Phase III randomized double‐blinded Clinical Trial of Hydroxyurea in Infants with SCA (BABY HUG) tested the hypothesis that hydroxyurea can prevent kidney dysfunction by reducing hyperfiltration.

Hydroxyurea is associated with lower costs of care of young children with sickle cell anemia

BACKGROUND AND OBJECTIVE: In the BABY HUG trial, young children with sickle cell anemia randomized to receive hydroxyurea had fewer episodes of pain, hospitalization, and transfusions. With anticipated broader use of hydroxyurea in this population, we sought to estimate medical costs of care in treated versus untreated children. METHODS: The BABY HUG database was used to compare inpatient events in subjects receiving hydroxyurea with those receiving placebo. Unit costs were estimated from the 2009 MarketScan Multi-state Medicaid Database for children with sickle cell disease, aged 1 to 3 years. Inpatient costs were based on length of hospital stay, modified by the occurrence of acute chest syndrome, splenic sequestration, or transfusion. Outpatient expenses were based on the schedule required for BABY HUG and a “standard” schedule for 1- to 3-year-olds with sickle cell anemia. RESULTS: There were 232 hospitalizations in the subjects receiving hydroxyurea and 324 in those on placebo; length of hospital stay was similar in the 2 groups. Estimated outpatient expenses were greater in those receiving hydroxyurea, but these were overshadowed by inpatient costs. The total estimated annual cost for those on hydroxyurea (

Recruitment of infants with sickle cell anemia to a Phase III trial: Data from the BABY HUG study

11 072) was 21% less than the cost of those on placebo (

Abdominal ultrasound with scintigraphic and clinical correlates in infants with sickle cell anemia: baseline data from the BABY HUG trial.

13 962; P = .038). CONCLUSIONS: Savings on inpatient care resulted in a significantly lower overall estimated medical care cost for young children with sickle cell anemia who were receiving hydroxyurea compared with those receiving placebo. Because cost savings are likely to increase with age, these data provide additional support for broad use of hydroxyurea treatment in this population.

Hydroxyurea Treatment of Young Children with Sickle Cell Anemia: Safety and Efficacy of Continued Treatment – the BABY HUG Follow-up Study

BACKGROUND Protocol-eligible subjects may not be candidates for research participation or may decline. To determine factors that affected accrual, we evaluated enrollment in BABY HUG, a multi-center, randomized, placebo-controlled Phase III trial of hydroxyurea (HU) in infants with sickle cell anemia. METHODS An anonymized registry of potential subjects served as the primary source of data. Study coordinators considered all infants less than age 18 months with a hemoglobin FS diagnosis on newborn screening. Data included the number of potentially eligible subjects, whether parents were approached, and reasons for participating or declining. RESULTS Of 1106 potential participants, 28% were not approached for reasons such as prior poor adherence to clinical care. Interested families expressed willingness to contribute to medical knowledge (51%), hope of being randomized to receive hydroxyurea (51%), and desire for closer clinical care (51%) as reasons for participating. Disease severity or the perception that their child was ill had less impact on willingness to participate (16%). Parents who declined cited fear of research (19%), transportation problems (14%), and the demanding nature of the study (25%). Ultimately, 234 (21%) gave informed consent, with little variability of acceptance rates among sites. Importantly, the number of subjects enrolled correlated with the number of families that were approached. Sites that excluded patients based on clinical/psychosocial biases were not more successful in recruiting than those who approached all eligible subjects. CONCLUSION Large, demanding clinical trials require an adequate pool of potential participants. Approaching all potentially eligible patients without predetermined biases enhances success in recruitment.

HydroxyureaIsAssociatedWithLowerCostsofCareof Young Children With Sickle Cell Anemia

OBJECTIVE The purpose of this study is to perform and evaluate baseline abdominal ultrasound in infants with sickle cell anemia who participated in the BABY HUG multiinstitutional randomized placebo-controlled trial of hydroxyurea therapy and to examine the potential relationships among ultrasound results and clinical, nuclear medicine, and laboratory data. SUBJECTS AND METHODS After local institutional review board approval and with informed guardian consent, 116 girls and 87 boys (age range, 7.5-18 months) with sickle cell anemia underwent standardized abdominal sonography at 14 institutions. Imaging was centrally reviewed by one radiologist who assessed and measured the spleen, kidneys, gallbladder, and common bile duct. Baseline physical assessment of spleen size, serum alanine aminotransferase and bilirubin levels, (99m)Tc sulfur colloid liver-spleen scans, and (99m)Tc diethylenetriaminepentaacetic acid clearance glomerular filtration rates (GFRs) were obtained. Analysis of variance and the Student test were performed to compare sonographic findings to published results in healthy children and to clinical and laboratory findings. RESULTS The mean (± SD) spleen volume (108 ± 47 mL) was significantly greater than published normal control values (30 ± 14 mL; p < 0.0001). There was no correlation between spleen volume and function assessed by liver-spleen scan. The mean GFR (125 ± 34 mL/min/1.73 m(2)) was elevated compared with control GFRs (92 ± 18 mL/min/1.73 m(2)). Renal volumes (right kidney, 29 ± 8 mL; left kidney, 31 ± 9 mL) were significantly greater than control volumes (right kidney, 27 ± 3 mL; left kidney, 27 ± 3 mL; p < 0.0001) and were positively correlated with GFR (p = 0.0009). Five percent of patients had sonographic biliary abnormalities (sludge, n = 6; dilated common bile duct, n = 2; and cholelithiasis and thickened gallbladder wall, n = 1 each). There was no correlation between biliary sonographic findings and laboratory results. CONCLUSION In infants with sickle cell anemia, sonographic spleen volume does not reflect function, but increased renal volume correlates with GFR and is consistent with hyperfiltration. Sonographic biliary abnormalities can occur early in life, while remaining clinically silent.