All participants will receive voxelotor once daily (QD), administered orally as tablets, dispersible tablets, or a stick pack formulation (powder blend formulation packaged as stick packs). Participants aged ≥ 12 years and/or ≥ 40 kgs will receive a voxelotor dose of 1500 mg QD. Participants aged < 12 years and < 40 kgs will receive weight based dosing of voxelotor. The participant's weight at study entry will be used to determine the starting voxelotor dose in this study. Participants may receive study drug as long they continue to receive clinical benefit that outweighs risk as determined by the investigator and/or until the participant has access to voxelotor from an alternative source.

All participants will receive voxelotor once daily (QD), administered orally as tablets, dispersible tablets, or a powder for oral suspension formulation (powder formulation packaged as stick packs).

An AE was defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered to be drug related. A treatment emergent AE was defined as an AE with an onset date on or after the date of informed consent until 28 days after discontinuation of drug. AEs included both serious AEs (SAEs) and all non-SAEs. An SAE was an AE or suspected adverse reaction that, at any dose, in the view of the either the investigator or sponsor, resulted in any of the following outcomes: death, was life-threatening, resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was important medical event; required inpatient hospitalization or prolongation of existing hospitalization.

An AE was defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered to be drug related. An SAE was an AE or suspected adverse reaction that, at any dose, in the view of the either the investigator or sponsor, resulted in any of the following outcomes: death, was life-threatening, resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was important medical event; required inpatient hospitalization or prolongation of existing hospitalization.

SCD-related AEs were common complications associated with the study participant's SCD and were not considered to be related to voxelotor unless judged by the investigator to have worsened in severity and/or frequency or changed in nature during the study. SCD-related complications included the following: sickle cell anemia with crisis, acute chest syndrome (ACS), pneumonia, priapism, and osteonecrosis. A treatment emergent AE was defined as an AE with an onset date on or after the date of informed consent until 28 days after discontinuation of drug. An SAE was an AE or suspected adverse reaction that, at any dose, in the view of either the investigator or sponsor, resulted in any of the following outcomes: death, was life-threatening, resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was important medical event; required inpatient hospitalization or prolongation of existing hospitalization.

Participants aged >= 12 years received voxelotor 1500 mg QD tablets. Participants aged < 12 years received a voxelotor dose based on their body weight to provide exposure corresponding to the adult dose of 1500 mg QD as powder for oral suspension or dispersible tablet or modified dispersible tablet. Participants received study drug as long they continued to receive clinical benefit that outweighed risk as determined by the investigator and/or until the participant had access to voxelotor from an alternative source.

An AE was defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered to be drug related. A treatment emergent AE was defined as an AE with an onset date on or after the date of informed consent until 28 days after discontinuation of drug. AEs included both serious AEs (SAEs) and all non-SAEs. An SAE was an AE or suspected adverse reaction that, at any dose, in the view of the either the investigator or sponsor, resulted in any of the following outcomes: death, was life-threatening, resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was important medical event; required inpatient hospitalization or prolongation of existing hospitalization.

The safety population included all participants who received at least 1 dose of study drug.

Participants aged >= 12 years received voxelotor 1500 milligrams (mg) once daily (QD) tablets. Participants aged < 12 years received a voxelotor dose based on their body weight to provide exposure corresponding to the adult dose of 1500 mg QD as powder for oral suspension or dispersible tablet or modified dispersible tablet. Participants received study drug as long they continued to receive clinical benefit that outweighed risk as determined by the investigator and/or until the participant had access to voxelotor from an alternative source.