Global Blood Therapeutics, Inc. is a clinical-stage biopharmaceutical company. The Company is engaged in discovering, developing and commercializing therapeutics to treat blood-based disorders. The Company is developing its initial product candidate, GBT440, as an oral, once-daily therapy for sickle cell disease (SCD). The Company is evaluating GBT440 in SCD in a Phase III clinical trial of GBT440 in adult and adolescent patients with SCD. GBT440 inhibits abnormal hemoglobin polymerization, the underlying mechanism of RBC sickling. The Company is also engaged in other research and development activities targeted towards hereditary angioedema (HAE). The Company's GBT440 is an investigational drug that increases hemoglobin's affinity for oxygen by binding to the alpha-chain of hemoglobin. GBT440 has been observed to keep a proportion of sickle hemoglobin (HbS), in its oxygenated state, where it cannot participate in polymerization.