The following article features coverage from the European Hematology Association (EHA) 2021 Virtual Congress. Click here to read more of Hematology Advisor‘s conference coverage.

In a study of pediatric patients with sickle cell disease (SCD) ages 4 to 11 years, treatment with voxelotor appeared to be well tolerated and was associated with increased hemoglobin. Study results were presented at the European Hematology Association (EHA) 2021 Virtual Congress by Clark Brown, MD, PhD, of Children’s Healthcare of Atlanta in Atlanta, GA, and colleagues.

Voxelotor has been approved in the US in treatment of SCD in adults and children 12 years of age or older. In the current study, the researchers aimed to evaluate voxelotor safety and efficacy in the younger age group of 4 to 11 years. These patients were treated with 1500 mg or 1500-mg weight-based equivalent voxelotor for a maximum of 48 weeks. Reported study outcomes were changes in hemoglobin over 24 weeks, changes in hemolytic markers (such as bilirubin, lactate dehydrogenase, and reticulocytes), adverse events (AEs), and other endpoints.

The study enrolled 45 patients, with a median age of 7.0 years (range, 4-11). The majority of patients (95.6%) had an HbSS genotype, and 84.4% were on hydroxyurea. Slightly over half (53.3%) of patients had at least 1 vaso-occlusive crisis in the year prior to entering the study.

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The mean baseline hemoglobin level was 8.6 g/dL, and by week 24 there was a mean change of +1.0 g/dL from baseline. A hemoglobin response, which was defined as >1 g/dL, was seen in nearly half (47.1%) of the patients. Reductions were seen in indirect bilirubin (-38.6%), lactate dehydrogenase (-2.6%), and percent reticulocyte count (-3.3%). Pharmacokinetic parameters were similar with voxelotor in patients aged 4 to 11 years and in patients aged 12 to 17 years.

Almost half of the patients (48.9%) had treatment-related adverse events that were unrelated to SCD, with diarrhea (11.1%), vomiting (11.1%), and rash (11.1%) being the most common. Most treatment-related AEs were grades 1 or 2, and 2 out of 45 treatment discontinuations were attributed to treatment-related AEs.

“Together, these results support the use of voxelotor in pediatric patients with sickle cell [disease], age 4 and older, as a potential strategy for early mitigation of the disease complications associated with sickle cell disease,” Dr Brown said in his presentation.

Disclosures: The author(s) have declared affiliations with or received grant support from the pharmaceutical industry. Please refer to the original study for a full list of disclosures.

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Estepp J, Kalpatthi R, Woods G, et al. Safety and efficacy of voxelotor in pediatric patients with sickle cell disease aged 4-11 years. Paper presented at: European Hematology Association 2021 Virtual Congress; June 2021; Abstract S260.