Table 5.

Pharmacokinetic parameters of O6-benzylguanine and O6-benzyl-8-oxoguanine

Dosage level
267 mg/m2 (n = 5)355 mg/m2 (n = 2)*472 mg/m2 (n = 7)628 mg/m2 (n = 2)835 mg/m2 (n = 3)
O6-BG CSS (ng/mL)31.8 (23.3-40.2)*20.124.9 (14.5-81.4)37.3 (19.4-55.2)20.2 (14.2-29.9)
8-oxoBG Css (ng/mL)730.5 (689-772)*747346 (258-612)289 (99-478)153 (88-238)
CLO6-BG (L/h/m2)42.5 (31.1-53.8)*62.350.2 (15.4-86.4)43.5 (22.6-64.4)62.0 (41.8-87.9)
  • NOTE: n, number of patients. Results are shown as median values and range in parenthesis.

    Abbreviations: CL, apparent oral clearance; Css, plasma concentration at steady state; O6-BG, O6-benzylguanine; 8-oxoBG, O6-benzyl-8-oxoguanine.

  • * Three of these patients received O6-BG at 15 mg/m2/d at this dosage level. Their median O6-BG Css, 8-oxoBG Css, and CLO6-BG values were 22.6 ng/mL (16.5-43.3), 588 ng/mL (66-1079), and 27.7 L/h/m2 (14.5-37.8), respectively.

  • One of these patients received O6-BG at 15 mg/m2/d at this dosage level. The O6-BG Css, 8-oxoBG Css, and CLO6-BG values were 55.5 ng/mL, 83.7 ng/mL, and 11.3 L/h/m2, respectively.