Study to Assess the Effect of Long-term Treatment With Voxelotor in Participants Who Have Completed Treatment in Study GBT440-031

Inclusion Criteria:

Male or female study participants with SCD who participated and received study treatment in Study GBT440-031.

Note: Participants in GBT440-031 who discontinued study drug due to an AE, but who remained on study may be eligible for treatment in this study provided the AE does not pose a risk for treatment with voxelotor.

1. Females of child-bearing potential are required to have a negative urine pregnancy test prior to dosing on Day 1.
2. Female participants of child-bearing potential must use highly effective methods of contraception to 30 days after the last dose of study drug. Male participants must use barrier methods of contraception to 30 days after the last dose of study drug.
3. Participant has provided written informed consent or assent (the ICF must be reviewed and signed by each participant; in the case of pediatric participants, both the consent of the participant's legal representative or legal guardian, and the participant's assent must be obtained).

Exclusion Criteria:

1. Female who is breast-feeding or pregnant.
2. Participant withdrew consent from Study GBT440-031.
3. Participant was lost to follow-up from Study GBT440-031.
4. Participant requiring chronic dialysis.
5. Any medical, psychological, safety, or behavioral conditions, which, in the opinion of the Investigator, may confound safety interpretation, interfere with compliance, or preclude informed consent.