The Effect of Renal Impairment on the Pharmacokinetics and Safety of Itacitinib

Itacitinib is a novel, selective, Janus kinase 1 inhibitor in development for treatment of graft‐versus‐host disease. The objective of this study was to assess pharmacokinetics and safety of 300‐mg itacitinib dosed in participants with normal renal function (n = 10), severe renal impairment (n = 8), and end‐stage renal disease (ESRD) on hemodialysis (n = 8). Serial plasma and urine samples (urine from normal and severe groups only) were collected before dosing until 72 hours after dosing. In the ESRD group, itacitinib was evaluated in 2 periods, when dosed before (period 1) and after (period 2) a hemodialysis session. Geometric mean ratios (90% confidence interval) in participants with severe renal impairment, ESRD period 1 and ESRD period 2 relative to participants with normal renal function were 1.65 (1.13‐2.39), 0.71 (0.49‐1.03), and 0.83 (0.57‐1.20) for maximum plasma drug concentration and 2.23 (1.56‐3.18), 0.81 (0.57‐1.16), and 0.95 (0.66‐1.35) for area under the plasma concentration–time curve from time zero to infinity. Itacitinib was well tolerated, and 3 grade 1 treatment‐emergent adverse events were reported over the course of the study. Given the magnitude of exposure changes in participants with severe renal impairment or ESRD and the historic risk‐benefit profile, no dose adjustment is recommended for itacitinib in patients with impaired renal function, although the final dosage recommendation will be based on cumulative pharmacokinetics and safety from this study and from the pivotal graft‐versus‐host disease trial. Additionally, itacitinib may be administered to patients undergoing dialysis regardless of the time of dialysis.