Patient disposition. *Other: (n = 2) > 20 transfusions/lifetime (note: patients were excluded before the protocol was amended to remove this criterion); (all n = 1): (i) iron chelation therapy < 6 months of study start (note: the protocol was amended to exclude patients with iron chelation therapy < 1 month of study start; however, this patient was excluded before this protocol amendment): (ii) concomitant hydroxyurea; (iii) concomitant autoimmune hemolytic anemia with severe anemia; (iv) ALT > 3× ULN (note: the protocol was amended to exclude patients with ALT > 5× ULN; however, this patient was excluded before this protocol amendment); (v) invalid creatinine results; (vi) safety concern; and (vii) rescreened by mistake.