Observed brain tumor pharmacokinetics of AZD1775 in 20 patients with glioblastoma following a single oral dose (100, 200, or 400 mg). A, Total AZD1775 tumor concentrations. B, Unbound AZD1775 tumor concentrations. C, Total AZD1775 tumor-to-plasma concentration ratios. D, Unbound AZD1775 tumor-to-plasma concentration ratios. Symbols represent observed data from individual patients, and lines represent median values.