Percentage of patients who had a reduction in the transfusion burden of at least 33% or at least 50% from baseline. Reductions in the transfusion burden (defined as the total number of red-cell units transfused in a specified time interval) were assessed in the intention-to-treat population. (A) The percentages of patients who had a reduction in the transfusion burden of at least 33% from baseline during weeks 13 through 24 (primary end point), during weeks 37 through 48 (first key secondary end point), and during any 12-week or 24-week interval. (B) The percentages of patients who had a reduction in the transfusion burden of at least 50% from baseline during weeks 13 through 24 (second key secondary end point), during weeks 37 through 48 (third key secondary end point), and during any 12-week or 24-week interval. A reduction of at least 2 red-cell units over the fixed and nonfixed 12-week intervals was also required for those end points. To control for multiple comparisons, key secondary end points were evaluated in sequential order once the primary efficacy analysis had shown statistical significance. Reprinted with permission from Cappellini et al.²⁴ Copyright © 2020 Massachusetts Medical Society.