Absolute Bioavailability of a Single, Fixed Subcutaneous Dose of Lecanemab in Healthy Subjects

• Published in: Alzheimer's & dementia Vol. 18; no. S10
• Main Authors: Rawal, Sumit, Duong, Anh, Landry, Ishani, Aluri, Jagadeesh, Boyd, Peter, Yagi, Takuya, Swanson, Chad J, Reyderman, Larisa
• Format: Journal Article
• Language: English
• Published: 01.12.2022
• ISSN: 1552-5260; 1552-5279
• DOI: 10.1002/alz.069438

Background Lecanemab is a humanized IgG1 monoclonal antibody that preferentially targets soluble aggregated Aβ species (protofibrils) with activity at insoluble fibrils. A subcutaneous (SC) formulation is in development as an alternative to intravenous (IV) infusion. The present study evaluated the absolute bioavailability (BA), pharmacokinetics (PK), safety and immunogenicity of lecanemab following a single fixed 700 mg SC dose. Methods This was an open‐label, parallel‐group study conducted in healthy subjects that were randomized into IV or SC dose group; 5 Japanese subjects were randomized to the SC dose group. Serum samples for determination of lecanemab PK parameters were collected after single dose of 10 mg/kg IV infused over approximately 1 hour or fixed 700 mg SC injection in the abdomen. The absolute BA was determined by the ratio of dose normalized area under the curve from zero to infinity (AUC(0‐inf)) for SC versus IV dosing. Results Thirty subjects received IV infusion and 29 subjects received SC injection. After SC dosing, maximum concentration was observed 72 hours post dose and was 4‐fold lower compared to IV infusion, which reflected the long absorption phase following SC administration compared with IV infusion. The AUC was 2‐fold lower for SC administration compared with IV infusion. Lecanemab half‐life (∼ 7 days) was similar following SC and IV administration. The absolute BA following a single SC 700 mg dose of lecanemab was 49.7% (90% CI: 43.5 – 56.8). PK of lecanemab after SC administration in Japanese subjects was similar to those in non‐Japanese subjects. Mild to moderate injection site reactions were experienced by 6 (20.7%) subjects in the SC dose group. Grade 1 and 2 infusion related reactions were experienced by 10 (33.3%) subjects in the IV dose group. One subject in IV and 2 in SC dose group, had confirmed treatment‐emergent positive anti‐drug antibodies (ADA), with low titers ranging from 16 to 32 with no subject being positive for neutralizing antibodies. Conclusion Lecanemab was well tolerated following both SC and IV administrations. The estimate of absolute BA of SC compared to IV dosing will be used to define SC dose and dosing regimen equivalent to IV dosing.