Changes in indicators of cerebral metabolic stress following treatment with voxelotor in children and adolescents with sickle cell anemia

Voxelotor is a small molecule that reduces the polymerization of sickle hemoglobin by increasing its affinity for oxygen. In patients with sickle cell anemia, it has been postulated that increasing hemoglobin-oxygen affinity could limit oxygen offloading from hemoglobin, causing an increase in cerebral metabolic stress. To investigate this hypothetical concern, we used multimodal brain imaging to define the effects of voxelotor on cerebral blood flow and oxygen extraction. We followed four patients for 2–5 months during and/or after voxelotor therapy. This study showed no observable increase in cerebral blood flow or oxygen extraction fraction during treatment.