Pharmacokinetic properties of insulin GZR4 after subcutaneous administration in the thigh, abdomen, or upper arm in healthy participants

Abstract Aims This trial aimed to evaluate the impact of different subcutaneous injection regions on the pharmacokinetics and safety of the once‐weekly basal insulin GZR4 in healthy Chinese participants. Materials and Methods This randomized, open‐label, three‐period crossover trial enrolled 24 healthy participants. Each participant received a single subcutaneous injection of GZR4 (3 nmol/kg) in the thigh, abdomen, and deltoid region of the upper arm (upper arm), respectively. This was followed by a four‐week observation period, with an additional one‐week interval between each injection. Blood samples were collected regularly to assess the pharmacokinetic (PK) characteristics of GZR4. The primary endpoint was the area under the concentration‐time curve from 0 to 672 h after a single dose (AUC 0–672h ) across injection regions. Secondary endpoints included additional PK parameters, safety, and immunogenicity. Results The GZR4 exposure (AUC 0–672h ) was comparable across injections in the thigh, abdomen, and upper arm. The geometric mean AUC 0–672h ratio (90% CI) for abdomen/upper arm was 104.8% (96.5%, 113.9%), for abdomen/thigh was 102.6% (94.5%, 111.4%), for thigh/upper arm was 102.2% (94.1%, 110.9%); all within the predefined equivalence range of 80.0%–125.0%. A total of 22 participants (91.7%) experienced 51 treatment‐emergent adverse events (TEAEs), and all TEAEs were mild or moderate in severity. No hypoglycaemic events, serious adverse events, or deaths were reported. Conclusions In healthy Chinese participants, subcutaneous injection of GZR4 in the thigh, abdomen, or upper arm displayed comparable drug exposure, with no clinically meaningful differences observed among the injection regions.