A Study of Etavopivat in Adults and Adolescents With Sickle Cell Disease (HIBISCUS)

Key Inclusion Criteria: * Provision of consent * Patient has a confirmed diagnosis of sickle cell disease * At least 2 episodes of vaso-occlusive crises in the past 12 months * Hemoglobin ≥ 5.5 and ≤ 10.5 g/dL (≥ 55 and ≤ 105 g/L) during screening * Patients taking hydroxyurea, must demonstrate a stable dose for at least 90 days prior to start of study treatment * Patients on crizanlizumab or L-glutamine treatment at the time of consent must be on a stable dose for ≥ 12 months and must be ≥ 80% compliant with the planned regimen at the time of consent and meet the VOC eligibility criteria * Female patients of childbearing potential must use highly effective methods of contraception, male patients are willing to use barrier methods of contraception Key Exclusion Criteria: * More than 15 vaso-occlusive crises within the past 12 months * Female who is breastfeeding or pregnant * Hepatic dysfunction characterized by: * Alanine aminotransferase (ALT) \> 4.0 × upper limit of normal (ULN) * Direct bilirubin \> 3.0 × ULN * Known HIV positivity * Active hepatitis B or hepatitis C infection * Severe renal dysfunction or on chronic dialysis * History of unstable or deteriorating cardiac or pulmonary disease within 6 months prior to consent including but not limited to the following: * Unstable angina pectoris or myocardial infarction or elective coronary intervention * Congestive heart failure requiring hospitalization * Uncontrolled clinically significant arrhythmias * Symptomatic pulmonary hypertension * History of overt clinical stroke within previous 2 years or any history of an intracranial hemorrhage * History of deep venous thrombosis requiring systemic anti-coagulation therapy for ≥ 6 weeks, occurring within 6 months prior to Day 1 of study treatment. Prior/Concomitant Therapy * Patients receiving regularly scheduled blood (RBC) transfusion therapy (also termed chronic, prophylactic, or preventive transfusion) * Receiving or use of concomitant medications that are strong inducers of CYP3A4/5 within 2 weeks of starting study treatment or anticipated need for such agents during the study * Use of voxelotor within 28 days prior to starting study treatment or anticipated need for this agent during the study * Use of an experimental selectin antagonist (eg, monoclonal antibody or small molecule) within 28 days of starting study treatment or anticipated need for such agents during the study * Use of erythropoietin or other hematopoietic growth factor treatment within 28 days of starting study treatment or anticipated need for such agents during the study * Receipt of prior cellular-based therapy (eg, hematopoietic cell transplant, gene modification therapy)