Bioequivalence of Two Firsekibart Subcutaneous Formulations: A Randomized, Double-Blind, Single-Dose, Parallel-Group Study in Healthy Chinese Participants.

We evaluated the pharmacokinetic (PK) bioequivalence and safety of a new formulation of firsekibart (solution for injection) compared with firsekibart lyophilized powder for solution. In this randomized, double-blind, parallel-group study, healthy Chinese adult males received a single subcutaneous dose of 200 mg firsekibart solution for injection (test product, T) or firsekibart powder for solution (reference product, R), followed through Day 141. The primary objective was to evaluate PK bioequivalence between T and R, concluded if least-squares geometric mean ratio (GMR) 90% confidence intervals (CIs) were within 80.00%-125.00%. Safety was also evaluated. A total of 181 participants received T (N = 90) or R (N = 91). PK profiles were comparable between T and R: least-squares GMRs (T/R; 90% CI) for the maximum serum concentration, area under the concentration-time curve (AUC) from time zero to the last time of quantifiable concentration, and AUC from time 0 to infinity were 104.26% (98.11%, 110.80%), 103.45% (98.15%, 109.04%), and 102.14% (96.75%, 107.83%), respectively. Most treatment-emergent adverse events were mild/moderate and generally comparable between T and R, with no treatment-related serious adverse events reported. Firsekibart solution for injection was bioequivalent to firsekibart lyophilized powder for solution for injection in healthy Chinese males, with no new safety signals identified.