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 μM. Plasma and CSF AUC0–∞ were 3.7 ± 1.7 and 2.1 ± 0.8 μM 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.