Total Hb and HbA^T87Q levels and transfusion requirements post–beti-cel infusion. (A) Patient schedule of total Hb (blue diamonds) and HbA^T87Q (red circles) measurements relative to transfusions received. Total Hb measurement of <9.0 g/dL was indicated as a common reason for transfusion. (B) Measurements of patient’s peripheral blood VCN levels by month postinfusion. Determination of peripheral blood VCN was performed as a pharmacodynamic measure of treatment efficacy in study HGB-204. In the study population, VCN in peripheral blood mononuclear cells correlated with the production of vector-encoded HbA^T87Q-globin levels.¹ BL, baseline; Hb, hemoglobin; SC, screening; VCN, vector copy number.