Safety and Pharmacokinetics of Single-Dose Mirikizumab in Chinese Healthy Participants: Results From a Phase 1 Study

The objective of this phase 1 single-dose study was to evaluate the safety, tolerability, and pharmacokinetics of mirikizumab in Chinese healthy adults. Sixty participants were randomized within 5 planned dose cohorts: intravenous (IV) 300 mg, IV 600 mg, IV 1200 mg, subcutaneous (SC) 200 mg, and SC 400 mg to receive mirikizumab (10 participants in each cohort) or placebo (2 participants in each cohort). No death or serious adverse events occurred. Twenty-eight (56.0%) participants who received mirikizumab reported 49 treatment-emergent adverse events (TEAEs) and 8 (80.0%) participants who received placebo reported 18 TEAEs. The majority of TEAEs were mild in severity. Following IV 300-1200 mg mirikizumab, the arithmetic mean of both area under the concentration versus time curve from time 0 to infinity (AUC_0-∞) and maximum observed drug concentration (C_max) increased by approximately 3.5-fold, and the arithmetic mean half-life (t_1/2) ranged from 9.64 to 12.0 days. Following SC 200 and 400 mg mirikizumab, the arithmetic mean of both AUC_0-∞ and C_max increased by approximately 1.6-fold, the median time to C_max (t_max) was 2.98 days for both, and the arithmetic mean t_1/2 was 10.6 and 10.5 days, respectively. Absolute bioavailability based on pooled SC and IV dose data was 38.2%. In this study, the safety and pharmacokinetic profile of mirikizumab were consistent with what has been reported in other studies.