A cohort of patients with sickle cell disease (SCD) required fewer blood cell units and had less risk of being hospitalized after adding voxelotor to their baseline hydroxyurea treatment, according to a single-center study recently published in Transfusion.

Voxelotor, a hemoglobin polymerization inhibitor approved in the US as an adjuvant to hydroxyurea treatment for SCD, has been associated with increased hemoglobin levels and decreased hemolysis in several studies. However, some authors hypothesize that an increased oxygen affinity of the hemoglobin-voxelotor complex could lead to decreased tissue oxygen availability, thus reducing its clinical benefits. 

Physicians from the Adult Sickle Center, Inova Schar Cancer Institute, Fairfax, Virginia added voxelotor to the treatment scheme for patients with SCD that presented hemoglobin levels below 7 g/dL or had symptomatic anemia. The authors recorded the number of hospitalizations and red cell units received by 13 patients during a full year of combined treatment with hydroxyurea and voxelotor and compared them with the data of the year before voxelotor became part of the scheme. 

All patients included in the study received a full voxelotor dose for most days of the studied year and had the HbSS genotype. The mean patient age was 37 years, with a range of 21 to 57 years.

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Both the average number of hospitalizations per year and of red blood units per patient were lower during voxelotor treatment, the former decreasing from approximately 5 per year to approximately 3 per year and the latter from 16.6 per patient to 9.6 per patient. 

Although the comparison between averages shows a clear overall benefit of voxelotor use, the response was actually variable from patient to patient. Some exhibited dramatic changes in the number of hospitalization and red cell units received; others showed virtually no change. 

“In this era of heightened concern for overall medical expenditures and blood conservation, our analysis provides a glimmer of hope that voxelotor treatment will prove both clinically and economically effective,” the authors concluded.

Reference

Bade NA, Giri U, Wang H, Ershler WB. Reduced red cell transfusions and hospitalizations in sickle cell patients treated with voxelotor—experience from a single center. Transfusion. Published online July 11, 2022. doi:10.1111/trf.16989