MEDI1814 selectively reduces free Aβ42 in cerebrospinal fluid of non-clinical species and Alzheimer's disease patients.

INTRODUCTION: Small molecules and antibodies are being developed to lower amyloid beta (Aβ) peptides. METHODS: We describe MEDI1814, a fully human high-affinity monoclonal antibody selective for Aβ(42), the pathogenic self-aggregating species of Aβ. RESULTS: MEDI1814 reduces free Aβ(42) without impacting Aβ(40) in the cerebrospinal fluid of rats and cynomolgus monkeys after systemic administration. MEDI1814 administration to patients with Alzheimer's disease (AD; n = 57) in single or repeat doses up to 1800 mg intravenously or 200 mg subcutaneously was associated with a favorable safety and tolerability profile. No cases of amyloid-related imaging abnormalities were observed. Predictable dose-proportional changes in serum exposures for MEDI1814 were observed across cohorts. Cerebrospinal fluid (CSF) analysis demonstrated central nervous system penetration of MEDI1814. Pharmacodynamic data showed dose-dependent suppression of free Aβ(42), increases in total (bound and free) Aβ(42), but no change in total Aβ(40) in CSF across doses. DISCUSSION: MEDI1814 offers a differentiated approach to impacting Aβ in AD via selective reduction of free Aβ(42).