Bioequivalence and Safety of Two Formulations of Tofacitinib Citrate Tablets in Healthy Chinese Volunteers under Fasting and Fed Conditions: Randomized, Open-Label, 2-Period, Single-Dose, Crossover Trials

Purpose. To evaluate the bioequivalence of two different tofacitinib citrate tablets formulations among healthy Chinese subjects under fasting and fed conditions and to observe the safety of test preparation and reference preparation in healthy subjects. Method. This randomized, open-label, 2-period, crossover, bioequivalence study included 64 healthy Chinese subjects (fasting: n = 32, fed: n = 32). The subjects were assigned to receive a single 5-mg dose of the test or a reference tofacitinib citrate tablets. Blood samples were collected at predose and up to 24 hours after dosing. Area under the plasma concentration time curve from zero to the last measurable concentration (AUC_0-t), the area from time zero to infinite (AUC_0-∞), and maximum plasma concentration (C_max) were used for bioequivalence assessment. Safety assessment was conducted by vital signs, physical examination, laboratory examination, and 12-lead electrocardiogram during the study, from the time the subject receiving the test drug to the end of the last visit. Results. Under fed condition, the 90% CIs of the geometric mean ratios of the test/reference for tofacitinib citrate tablets were 98.40–104.16% for AUC_0-t, 89.96–116.70% for C_max, and 98.50–104.15% for AUC_0-∞. Under fasting condition, the 90% CIs of the geometric mean ratios of the test/reference for tofacitinib citrate tablets were 93.65–101.60% for AUC_0-t, 90.06–109.15% for C_max, and 93.88–101.51% for AUC_0-∞. There were no serious events. Conclusion. The 90% CI for the geometric mean ratio (test/reference) of C_max, AUC_0-t, and AUC_0-∞ were within the range of 80.00%–125.00%, indicating that the test formulation was equivalent to the reference formulation in healthy Chinese subjects under both fasting and fed conditions. They are similar in terms of safety. This trial is registered with CTR20190366.