RecruitingPhase 2Drug trialA Study to Evaluate the Pharmacokinetics and Safety of Etavopivat in Pediatric Patients With Sickle Cell DiseaseThis study is being done to learn about etavopivat, a once a day medicine taken by mouth in adolescents with sickle cell disease. The main goals are to study safety and how long etavopivat stays in the bloodstream, while also studying if there are benefits from taking etavopivat. Eligible participants who enter the study will start a 96-week treatment period. At the end of the 96 weeks, participants will have an end of study visit that occurs 4 weeks later. The participants will receive etavopivat every day throughout the treatment period.