Statistical associations between baseline laboratory parameters and treatment characteristics with the MTD %HbF.

Significant positive associations (r) were identified for the baseline %HbF value (panel A, r = 0.43,P = .001), the baseline hemoglobin concentration (panel B,r = 0.34, P = .01), and the MTD dose (panel C, r = 0.33, P = .02). A significant negative association was identified between the percentage of pills returned and the MTD %HbF value (panel D, r = −0.32,P = .02).