Single‐ and multiple‐dose pharmacokinetics of tofacitinib in healthy Chinese volunteers

Abstract Tofacitinib is an oral Janus kinase inhibitor. The objective of this phase 1, open-label study was to characterize the single- and multiple-dose pharmacokinetics (PK) of tofacitinib in 12 healthy, adult Chinese volunteers. Eligible subjects received oral tofacitinib 10 mg once daily on days 1 and 6 and twice daily on days 2-5. Blood samples were collected on day 1 predose and over 24 hours postdose (day 2 predose), predose on days 3-6, and over 12 hours postdose on day 6. PK parameters were calculated using noncompartmental analysis. Mean concentration-time profiles for days 1 and 6 were similar, with median time to peak concentration of 0.5 hours on both days. Plasma concentrations declined rapidly following attainment of peak concentrations, with a mean terminal half-life of 3.3 hours on day 1 (single dose) and 2.5 hours on day 6 (multiple dose). No accumulation in plasma occurred with twice-daily administration: accumulation ratio of 1.04. The rapid absorption, elimination, and systemic exposures (peak and area under the concentration-time curve) observed in healthy Chinese volunteers in this study are similar to those previously reported in white subjects.