• Male or female subjects with confirmed diagnosis of SCD, including only HbS/S or HbS/βT0 genotype.

• Subjects who had at least 1 and no more than 10 vaso-occlusive crises (VOC) episodes reported within 12 months prior to screening.

• Body weight ≥40 kg and ≤120 kg at screening and baseline.

• Subjects on concomitant hydroxyurea must be on a stable dose (mg/kg) for ≥3 months prior to screening Visit V1

• Female subjects of childbearing potential, must have negative pregnancy, must have stopped breastfeeding as of first dose, and must either commit to true abstinence from heterosexual contact or must be willing to use adequate contraceptive precautions.

• Male subjects must practice true abstinence or agree to use a condom during sexual contact with a pregnant female or a female of childbearing potential