A randomized, placebo-controlled, single ascending-dose study to assess the safety, tolerability, pharmacokinetics, and immunogenicity of subcutaneous tralokinumab in Japanese healthy volunteers.

Tralokinumab is a human monoclonal antibody in clinical development for asthma and atopic dermatitis that specifically neutralizes interleukin-13. This phase I, single-blind, randomized, placebo-controlled, single ascending-dose study assessed the safety, tolerability, pharmacokinetics (PK), and immunogenicity of subcutaneous tralokinumab (150, 300, or 600 mg) in thirty healthy Japanese adults. The most frequent treatment-emergent adverse event (TEAE) in all treatment groups was injection-site pain. The frequency and severity of TEAEs was similar across tralokinumab doses. Cmax , AUC(0-t) , and AUC(0-inf) increased in a dose-proportional manner, and mean t1/2 ranged from 20 to 25 days. No anti-drug antibodies were detected. A post-hoc pooled population PK modeling analysis, incorporating PK data from this study, demonstrated that Japanese individuals had greater systemic exposure to tralokinumab than non-Japanese individuals. This difference was not clinically relevant and was primarily due to differences in body weight, with lower body weight associated with greater PK exposure. Japanese ethnicity was not a significant predictor of tralokinumab PK. This study indicates that single-dose subcutaneous administration of tralokinumab 150-600 mg was well tolerated in Japanese healthy volunteers, and supports the 300 mg dose selection for Japanese patients with asthma in ongoing clinical trials.