Voxelotor reduces the occurrence of vaso-occlusive crises (VOCs) and the need for blood transfusions in patients with sickle cell disease (SCD) by inhibiting sickle hemoglobin (HbS) polymerization, according to study findings published in Expert Review of Hematology.

Nirmish Shah and colleagues conducted a retrospective analysis of real-world data from the Symphony Health Solutions Integrated Dataverse database collected between January 1, 2012, and June 30, 2021. The researchers compared the data from before and after 3128 individuals with SCD aged 12 years and above started taking voxelotor.

“Results of this study suggest that voxelotor . . . may lead to reductions in the annualized rate of VOCs and the need for transfusions and hospital visits,” the authors said. “The data . . . provide additional support for the use of this novel therapy in the treatment of hemolytic anemia and the management of associated complications in the SCD population.”

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Prior to voxelotor treatment, 54.2% of the patients experienced 1 or more VOC events while the remaining 45.8% did not. Voxelotor lowered the VOC rate by 23%, from 10.9 to 8.4 (P <.001), and the transfusion rate by 52%, from 7.0 to 3.3 (P <.001).

The average hemoglobin level was 7.8 g/dL for the 97 patients with available laboratory data before voxelotor administration. Following voxelotor treatment, the mean hemoglobin level was 8.9 g/dL, with 60.8% of patients experiencing a hemoglobin increase of 1 g/dL and 41.9% experiencing an increase of greater than 2 g/dL.

Length of hospital stay decreased by 30%, from 21.2 days to 14.7 days (P <.001). For the 609 patients hospitalized within 3 months of starting voxelotor, the rate of hospitalization related to VOC decreased by 34%, from 7.2 to 4.8 (P <.001). The average number of outpatient visits decreased by 10%, from 24.8 to 22.5 (P =.006).


Shah N, Lipato T, Alvarez O, et al. Real-world effectiveness of voxelotor for treating sickle cell disease in the US: a large claims data analysis. Expert Rev Hematol. Published online February 22, 2022. doi:10.1080/17474086.2022.2031967