Steady-state imatinib trough levels by body weight, body surface area, and age at start of study. The predicted imatinib trough levels using linear regression analyses were described by 1763 − 413 × BSA (r² = 0.038, A), 1266 − 3.5 × body weight (r² = 0.015, B), and 695 + 5.9 × age (r² = 0.02, C). Linear regression lines are shown.