Voxelotor Shows Significant Reduction in Transfusions, VOCs in Patients with SCD


Data show most patients (60.3%) with sickle cell disease achieved a Hb increase of >1 g/dL during the follow-up period.

Nirmish Ramesh Shah, MD

Nirmish Ramesh Shah, MD

In a recent study, a team of investigators led by Nirmish Shah, MD, Division of Hematology, Duke University School of Medicine assessed the real-world impact of voxelotor treatment on the rates and management of complications related to sickle cell disease.

They observed voxelotor increased hemoglobin (Hb) by ≥1 g/dL, with study data suggesting statistically significant reductions in transfusions, vaso-occlusive crises (VOCs), and all-cause VOC-related hospitalizations after voxelotor use.

The study was presented at the 2021 American Society of Hematology (ASH) Annual Meeting & Exposition.


Data from the Symphony Health claims database included medical and pharmacy claims included patients aged ≥12 years with SCD who initiated voxelotor therapy between November 2019 - March 2021.

They included patients with ≥1 year’s data before the index date, considered the date of the first voxelotor claim for each patient, in the analysis.

Additionally, baseline demographic and clinical characteristics were summarized through descriptive and inferential statistics, while also comparing annualized rates per patient-year (PPY) for transfusions, VOCs, VOC-related and all-cause hospitalizations, and before and after voxelotor initiation.

They evaluated hemoglobin (Hb) responses for a subset of patients whose Hb lab data were available (≥1 Hb value recorded 30 days before initiation of vocelotor and ≥1 Hb value recorded after the index date).


A total of 2695 eligible patients from the Symphony Health claims database were included in the analysis, with a mean age of 34.6 years and 60% female as of March 2021. From this number, 915 patients (34%) had ≥1 VOC in the 3 months before initiating voxelotor.

Of the subset of patients with pre- and post-voxelotor Hb measurements (n = 63), the mean Hb (95% confidence interval) was 7.9 (7.5 - 8.2) g/dL at baseline and the final Hb 8.9 (8.4 - 9.4) g/dL after voxelotor initiation.

Data show most patients (38 of 63, 60.3%) achieved Hb increase of >1 g/dL at any point during the follow-up period.

In patients who received ≥1 transfusion (n = 357) in the year before voxelotor initiation, the mean transfusion rate decreased by 43% from 3.2 (2.8 - 3.7) to 1.8 (1.4 - 2.3) PPY (P <.001).

Further, in 40 patients receiving chronic transfusions (≥8), the mean transfusion rate decreased by 34%, from 9.8 (8.3 - 11.4) to 6.5 (4.4 - 8.5) PPY (P = .007).

Among those who had ≥1 VOC in the 3 months prior to voxelator initiation, the mean annualized VOC rate decreased by 22%, from 10.9 (10.4 - 11.5) to 8.5 (7.8 - 9.3), (P <.001). In addition, the mean rate of VOC-related hospitalizations decreased by 32%, from 7.3 (6.9 - 7.7) to 5.0 (4.4 - 5.6) (P <.001).

Then, in 636 patients previously hospitalized in 3 months prior to voxelotor initiation, the mean all-cause hospitalization rate was reduced by 36%, from 7.5 (7.1 - 7.9) to 4.8 (4.3 - 5.3) after treatment (P <.001).


“This real-world evidence provides additional support for the use of voxelotor in the treatment of hemolytic anemia and the management of its associated complications,” investigators wrote.

The study, “Real-World Experience of Voxelotor for the Management of Complications in Sickle Cell Disease,” was published online by ASH.

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