Purpose: ABT-888 inhibits poly(ADP-ribose) polymerase (PARP) and may enhance the efficacy of chemotherapy and radiation in CNS tumors. We studied the plasma and cerebrospinal fluid (CSF) pharmacokinetics (PK) of ABT-888 in a non-human primate (NHP) model that is highly predictive of human CSF penetration.
Methods: ABT-888, 5 mg/kg, was administered orally to three NHPs. Serial blood and CSF samples were obtained. Plasma and CSF concentrations of ABT-888 were measured using LC/MS/MS, and the resulting concentration versus time data were evaluated using non-compartmental and compartmental PK methods.
Results: The CSF penetration of ABT-888 was 57+/-7% (mean+/-SD). The peak ABT-888 concentration in the plasma was 0.62+/-0.18 microM. Plasma and CSF AUC0-infinity were 3.7+/-1.7 and 2.1+/-0.8 microM h. PARP inhibition in peripheral blood mononuclear cells was evident 2 h after ABT-888 administration.
Conclusion: The CSF penetration of ABT-888 after oral administration was 57%. Plasma and CSF concentrations were in the range that has been shown to inhibit PARP activity in vivo in humans.