A complete response was defined as hemoglobin \>12 grams per deciliter (g/dL) not attributed to a transfusion effect and the normalization of hemolytic markers. No transfusion effect was defined as \> 1 week since the last transfusion.

A partial response was defined as hemoglobin 10-12 g/dL or at least a 2 g/dL increase from Baseline not attributed to a transfusion effect and the normalization of hemolytic markers. No transfusion effect was defined as \> 1 week since the last transfusion.

An adverse event (AE) was defined as any untoward medical occurrence associated with the use of a drug in humans, whether or not considered drug related, that occurred after a participant provided informed consent. Abnormal laboratory values or test results occurring after informed consent constituted AEs only if they induced clinical signs or symptoms, were considered clinically meaningful, required therapy, or required changes in the study drug. Anemia and transfusions should not have been reported as AEs unless they represented a clinically meaningful decrease from Baseline in hemoglobin. A TEAE was defined as any AE either reported for the first time or the worsening of a pre-existing event after the first dose of study drug.