Duration of mean hemoglobin increase from baseline. Kaplan-Meier plot of duration of mean hemoglobin increase from baseline ≥1.0 g/dL over rolling 12-week intervals. Patients receiving placebo were assessed up to crossing over to luspatercept treatment. The luspatercept group does not include crossover patients. Hemoglobin assessment was done using the consecutive rolling 12-week intervals within the double-blind treatment period (ie, from day 2 to day 85, etc). Duration assessment started from the first day of the first rolling 12-week interval during which mean hemoglobin increase from baseline ≥1.0 g/dL was achieved and ended with the last day of the last consecutive rolling 12-week interval during which mean hemoglobin increase from baseline ≥1.0 g/dL was maintained. A patient was censored at the efficacy cutoff, defined as minimum (death date, study discontinuation date, last dose date +20).