Voxelotor improves red blood cell functionality in children with sickle cell anaemia: An ancillary study of the HOPE-KIDS 1 trial.

INTRODUCTION: Sickle haemoglobin (HbS) polymerisation perturbs red blood cell (RBC) rheology and drives sickle cell disease (SCD) pathophysiology. Voxelotor is an HbS polymerisation inhibitor that increases haemoglobin (Hb)-oxygen affinity. METHODS/RESULTS: In this 48-week, prospective, single-centre translational study, 10 children aged 4-11 years with SCD were treated with voxelotor. Improvements in RBC deformability were observed using osmotic/oxygen gradient ektacytometry, with increases in minimal and maximal elongation index and reductions in point of sickling. Increased Hb and reduced markers of haemolysis were also observed. CONCLUSION: These findings suggest that voxelotor treatment is associated with reduced RBC sickling and haemolysis in children with SCD.

Pharmacokinetics of Voxelotor in Patients With Renal and Hepatic Impairment.

Two open-label studies assessed the safety, tolerability, and pharmacokinetics of Oxbryta (voxelotor) in subjects with hepatic or renal impairment. Eight subjects with severe renal impairment (estimated glomerular filtration rate <30 mL/min/1.73 m2 ) and 8 healthy age-, sex-, and body mass index-matched controls were administered a single oral dose of voxelotor 900 mg. Seven patients with mild (Child-Pugh A), moderate (Child-Pugh B), and severe (Child-Pugh C) hepatic impairment and healthy age-, sex-, and body mass index-matched controls (7:7:7:7) were administered a single oral dose of voxelotor 1500 mg, except those with severe hepatic impairment (600 mg). There was no apparent effect of renal function on the excretion of voxelotor based on comparable half-life values between subjects with severe renal impairment and healthy matched controls. Mean area under the concentration-time curve from time 0 to infinity (AUC0-inf ) values were lower by approximately 50% (plasma) and 25% (whole blood) in subjects with severe renal impairment compared with controls. Accordingly, dose adjustment is not required in patients with severe renal impairment. Voxelotor plasma and whole-blood exposures were slightly increased in subjects with mild and moderate hepatic impairment. Mean AUC0-inf values were approximately 9% to 18% higher compared with those of healthy matched controls. Dose adjustment is therefore not required in patients with mild or moderate hepatic impairment. Voxelotor mean AUC0-inf values were approximately 90% higher in subjects with severe hepatic impairment. A lower voxelotor dose (1000 mg) is recommended for patients with severe hepatic impairment. Voxelotor was well tolerated in all treatment groups.