MAP2K7 and neurofibromatosis type 1: Other preclinical studies in healthy mice and rats have shown a diminished ability of selumetinib to penetrate the brain compared to other MEK inhibitors, suggesting poor penetration of selumetinib against an intact BBB.25,35,37,38 The median brain–plasma ratio of selumetinib in minipigs was 0.1, which is similar to that seen in a preclinical study with a panel of MEK inhibitors in healthy mice.37 Nonetheless, selumetinib was detected in both the optic nerve and the cerebral cortex and showed a pharmacodynamic effect in optic nerve from NF1 minipigs after a single dose.