Etavopivat is a medicine being studied to help people with sickle cell disease, a condition where red blood cells (RBCs) are sickle-shaped and can block blood flow, causing pain. This study will see if etavopivat can make hemoglobin, a protein in blood that carries oxygen, work better and reduce painful events called vaso-occlusive crises. The study compares etavopivat to a placebo (a pill with no medicine). It is a Phase 2/3 study, meaning researchers want to see how well the medicine works and how safe it is.

• Participants must be 12 to 65 years old and have sickle cell disease.
• The study lasts 52 weeks with a chance to continue for another 112 weeks.
• Women must use birth control, and men should use barrier methods during the study.

To join, participants need to have had at least two painful events in the past year, but not more than 15. People with certain health issues, like liver problems, severe kidney problems, or a recent stroke, cannot join. Participants must not be on certain other medications or treatments before or during the study.