PITTSBURGH – Children with sickle cell disease (SCD) who were started on hydroxyurea in infancy had significantly better outcomes than do children started on the drug as toddlers, researchers report.
Among 65 children with SCD, those who started on hydroxyurea before age 1 year had significantly fewer hospitalizations, pain crises, and transfusions in the first 2 years of life, compared with patients started on the drug during 1-2 years of age or after age 2 years, found Sarah B. Schuchard, PharmD, from the SSM Health Cardinal Glennon Children’s Hospital in St. Louis and her colleagues.
Neil Osterweil/MDedge News
Dr. Sarah B. Schuchard
At the Children’s Hospital and Clinics of Minnesota in Minneapolis, where Dr. Schuchard recently completed her training and conducted the research, the goal is to initiate all infants with sickle cell anemia and sickle-beta0-thalassemia on hydroxyurea within this first year of life.
To evaluate outcomes associated with this practice, the investigators conducted a retrospective review of all children with SCD who began hydroxyurea therapy at their center during 2008-2016.
They divided the population into three cohorts. Patients in cohort 1 were started on hydroxyurea before age 1 year (35 patients; mean age, 7.2 months), those in cohort 2 started between 1 and 2 years of age (13 patients; mean age, 19.5 months) and those in cohort 3 were started after 2 years of age (three patients; mean age, 35.5 months).
All patients had been diagnosed with either sickle cell anemia or sickle-beta0-thalassemia, and all had at least two laboratory assessments at 6 months, 12 months, 18 months, or 24 months of age.
For the coprimary endpoint of laboratory data, the investigators found that patients in cohort 1, the early starters, had significantly higher hemoglobin (P = .0003), lower absolute reticulocyte counts (P = .0304), and mean corpuscular volume (P = .0199) than did the patients in cohort 3.
Infants in cohort 1 had significantly lower white blood cell counts than did the patients in either cohorts 2 or 3 (P = .0007 and P less than .0001, respectively) and lower absolute neutrophil counts (P = .0364 and .0025, respectively), although no patients required hydroxyurea therapy to be held because of low ANC.
Clinical events, the other coprimary endpoint, were also significantly better among patients in cohort 1, who had significantly fewer hospitalizations (P = .0025), a trend toward fewer painful events (P = .0618), and significantly fewer transfusions (P = .0426) than did patients in the other two cohorts.
“Early hydroxyurea also appears to contribute to fewer pain crises requiring admission,” the investigators noted.
They noted that in their study, the hematologic response was greater than that seen in the BABY HUG study, which studied the protective effects of hydroxyurea in children aged 9-18 months. The mean age of hydroxyurea initiation was 13.6 months in that study, compared with 7.2 months in the study by Dr. Schuchard and her colleagues.
“It would be interesting to see if the splenic and renal function (the unmet primary endpoints of BABY HUG) are preserved in patients starting hydroxyurea at this younger age,” they wrote.
The study was internally funded. Dr. Schuchard reported having no conflicts of interest.
SOURCE: Schuchard S et al. ASPHO 2018, Poster 342.