A randomized, double-blind, comparative study of the pharmacodynamics and pharmacokinetics of GP40141 (romiplostim biosimilar) and reference romiplostim in healthy male volunteers.

Aims: The pharmacodynamic (PD) similarity between GP40141, a proposed romiplostim biosimilar, and reference romiplostim was evaluated. Pharmacokinetics and safety were also assessed.

Methods: In this phase 1, randomized, double-blind, single-dose, crossover comparative study with an adaptive design, 56 healthy male volunteers were randomized 1:1 to receive a 3 ug × kg subcutaneous dose of GP40141 and reference romiplostim. The PD similarity between GP40141 and the reference romiplostim was determined using the standard equivalence criteria (80%-125%) for the area under the platelet count-time curve from time 0 to the time of the last sampling for PD (AUC ) and the maximum observed platelet count (P ).

Results: GP40141 and the reference romiplostim exhibited similar PD profiles. 90% CI for the geometric mean ratios for the primary PD parameters (AUC P ) for GP40141 (T) and the reference romiplostim (R) were fully contained within the predefined equivalence limits of 80%-125%: 98.13%-102.42% for AUC and 97.56%-105.80% for P . The pharmacokinetic profiles of GP40141 and the reference romiplostim were well described. No adverse events were observed during the clinical trial after the administration of GP40141 and the reference romiplostim.

Conclusion: This study demonstrates the PD similarity of GP40141 to the reference romiplostim. Both treatments had comparable safety profiles (NCT05652595).