CONCLUSION
In summary, this study was the first PPK model for busulfan that successfully incorporated GSTA1 genotypes in a Chinese pediatric population and partly explained the source of large variability of busulfan exposure, suggesting that TDM would be necessary for optimization of pediatric Bu treatment. Moreover, a BSA-based dosing regimen is recommended for individual busulfan therapy in order to weaken variability in busulfan exposure and to enhance the safety and efficacy of Bu treatment. Finally, an optimal LSS (C2h and C4h) would be convenient for TDM in the future.