Palbociclib (PD-0332991) pharmacokinetics in subjects with impaired renal function.

Purpose This publication describes an evaluation of the impact of different degrees of renal impairment on the pharmacokinetics and safety of palbociclib after a single 125-mg oral dose. Methods Thirty-one subjects were assigned to different renal function groups. Serial blood sampling for pharmacokinetics was performed up to 120 h and 168 h post-palbociclib dose for subjects with normal and impaired renal function, respectively. A separate blood sample was collected at pre-dose and 8 h after dosing to measure plasma protein binding. Plasma palbociclib was measured using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. Plasma protein binding samples were processed by equilibrium dialysis and measured by a validated LC-MS/MS method. Results Plasma palbociclib exposure was higher in subjects with renal impairment than in subjects with normal renal function; however, there were no marked differences in exposure across subjects with mild, moderate, and severe renal impairment. Total plasma exposure AUCinf increased by 39%, 42%, and 31% with mild, moderate, and severe renal impairment, respectively, relative to subjects with normal renal function. Peak exposure Cmax increased by 17%, 12%, and 15% for mild, moderate, and severe impairment, respectively. There was no obvious trend in the mean fu with worsening renal function. The PBPK model adequately described palbociclib exposure observed in subjects with moderate or severe renal impairment from this study. Conclusion Palbociclib was safe and well-tolerated in a small population of subjects with normal and impaired renal function after a single oral 125 mg dose. No dose adjustment is required in patients with renal impairment.