Sickle cell disease (SCD) is characterized by chronic hemolytic anemia and intermittent vasoocclusive crises. To date, 4 disease-modifying drugs have been approved for the treatment of SCD: hydroxyurea (an S-phase inhibitor), L-glutamine (an amino acid), crizanlizumab (a P-selectin inhibitor), and voxelotor (a hemoglobin S polymerization inhibitor). Preclinical studies suggested that voxelotor effectively treats SCD and sickle cell anemia (SCA). In a phase III trial, voxelotor-treated patients showed significantly elevated hemoglobin levels (>
1 g/dL from baseline) compared to placebo-treated patients. The group that received voxelotor also showed a greater decrease in hemolytic markers but a comparable incidence of side effects. Six ongoing clinical trials also sought to ascertain the effectiveness and safety of high-dose voxelotor when administered to children younger than 12 years. Studies assessing their long-term efficacy and safety are needed to fully understand the role of voxelotor in treating SCD/SCA. In this review, we discuss the mechanisms, trials to date, and future treatment directions of voxelotor.