Pharmacokinetics of Depemokimab Delivered by Safety Syringe Device or Autoinjector in Healthy Adults: A Phase 1, Single-Dose Study

This Phase I, randomized, multicenter, open-label, parallel-group, single-dose study assessed the relative bioavailability of the anti–interleukin-5 antibody depemokimab (100 mg) when administered subcutaneously via either a safety syringe device (SSD) or an autoinjector (AI). Healthy adult participants were randomized I:I to SSD or AI treatment arms and I:I:I to the injection site (upper arm, abdomen, or thigh). Participants were followed up for 30 weeks; blood samples were collected for pharmacokinetic (PK) assessment before dosing on Day 1 and up to Week 26. Depemokimab concentration profile as measured by plasma maximum concentration (C_max), the area under the concentration–time curve from time zero extrapolated to infinity (AUC_0-inf), PK parameters, immunogenicity, and safety were assessed. Overall, 140 participants were enrolled (n = 70 per arm). Mean plasma concentration-time profiles of depemokimab were similar in both treatment arms, regardless of the injection site, adjusted geometric mean AI:SSD ratios for C_max and AUC_0-inf were 1.03 and 1.03, respectively, with all 90% confidence intervals within the bioequivalence bounds of 0.80-1.25. PK parameters were comparable across treatment arms. Treatment-related adverse events were reported in 19% of SSD and 20% of AI participants, with headache being the most common across both arms; no adverse events led to study withdrawal. These results support the use of either SSD or AI for subcutaneous administration of depemokimab.