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

Etavopivat is designed to activate PKR and thereby modulate RBC metabolism by impacting two critical pathways in RBCs. The etavopivat clinical development program will investigate whether decreasing 2,3-DPG may help oxygen bind to hemoglobin (i.e. increasing oxygen affinity), and thereby increase ATP and impact RBC function. This study is a randomized, placebo-controlled, double-blind, multicenter Phase 2/3 study of patients age 12 to 65 years (inclusive), with sickle cell disease. There is one planned interim analyses in this study design. Initially, patients will be randomized at 1:1:1 to one of two dose levels of etavopivat or placebo. At the first interim analysis, one of the two etavopivat dose levels will be selected for the Phase 3 portion of the study, in which patients will be randomized at 1:1 to the selected etavopivat dose or placebo. Efficacy on hemoglobin will be evaluated at conclusion of the double-blind treatment period. Following completion of 52 weeks of double-blind treatment, patients may enter a 112-week etavopivat open-label extension period.