Engineering anti-amyloid antibodies with transferrin receptor targeting improves brain biodistribution and mitigates ARIA

Although the first generation of immunotherapies for Alzheimers disease (AD) are now clinically approved, amyloid-related imaging abnormalities (ARIA) remain a major safety problem for this class of drugs. Here, we report an antibody transport vehicle (ATV) targeting the transferrin receptor (TfR) for brain delivery of amyloid beta (A{beta}) antibodies that significantly reduced ARIA-like lesions and improved plaque target engagement in a mouse model of amyloid deposition. Asymmetrical Fc mutations (ATVcisLALA) allowed the molecule to selectively retain effector function only when bound to A{beta} while mitigating TfR-related hematology liabilities. Mice treated with ATVcisLALA:A{beta} exhibited broad brain parenchymal antibody distribution; in contrast, anti-A{beta} IgG was highly enriched at arterial perivascular spaces where vascular A{beta} localizes and likely plays a role in induction of ARIA. Importantly, ATVcisLALA: A{beta} almost completely eliminated ARIA-like lesions and vascular inflammation associated with anti-A{beta} treatment. Taken together, ATVcisLALA has the potential to significantly improve both safety and efficacy of A{beta} immunotherapy through enhanced biodistribution mediated by transport across the blood-brain barrier.