Unique Hemoglobinopathy Pattern Following Treatment with Voxelotor.

Objective: Voxelotor, a FDA-approved drug for the treatment of patients with sickle cell disease (SCD), inhibits hemoglobin S (HbS) polymerization and increases total hemoglobin via hemolysis reduction. This drug has shown unique patterns in hemoglobin fractionation, affecting its interpretation. We aimed to evaluate whether these voxelotor-induced changes can be linked to improvement of hemolysis markers in pediatric patients on voxelotor.

Methods: A total of 15 patients (age 12 to 20 years; 40% females) on voxelotor were evaluated to compare changes in the hemoglobin fractionation by capillary electrophoresis, total hemoglobin, reticulocyte percentage (retic%), lactate dehydrogenase (LDH), and bilirubin measurements before and after the recorded date of voxelotor prescription.

Results: Hemoglobin fractionation showed changes in the profile of 60% (9/15) of the patients studied. Out of the 9 patients for which voxelotor showed changes in the hemoglobin fractionation, 44% (4/9) had an increase of >1 g/dL in their total hemoglobin after voxelotor treatment was started. Assessment of other hemolysis markers available showed decreased LDH (4/4), retic % (6/8), and bilirubin (3/4).

Conclusions: Unique pattern of hemoglobin fractionation analysis following therapy with voxelotor has potential as a tool for the assessment of response and/or compliance to voxelotor for the treatment of SCD.