Grandchildren of GRNDaD: Shifts in disease-modifying therapy at the adolescent transition in sickle cell disease

Characterizing the modern person living with sickle cell disease (SCD) in the United States has been limited without a well-curated longitudinal registry. To address this, the Globin Research Network for Data and Discovery (GRNDaD) registry strives to collect clinical outcomes and quality of life metrics from Institutional Review Board-approved centres across the United States. Here, we examined the use of different disease-modifying therapies in (actively consented) adults and children with HgbSS and HgbS-β0 thalassaemia (SCA) from 38 sites. Of the 3169 active patients in GRNDaD, about 65% of subjects were on hydroxyurea (hydroxycarbamide; HU), and 2130 had SCA. As predicted, the absolute neutrophil counts were lower and mean corpuscular volumes were higher for patients on HU. However, there was a lower proportion of patients on HU in older age groups. In contrast, chronic RBC transfusion utilization was nearly twice as high in the 18- to 29-year-old age group than in the 11- to 17-year-old age group. For novel therapeutics, we examined use prior to voxelotor's removal from the market and prior to publication of the negative phase III trial of crizanlizumab. Voxelotor utilization in this cohort was three times that reported by claims data while crizanlizumab usage was nearly double, suggesting high-quality comprehensive sickle cell care could increase utilization of novel therapies.