Understanding and Overcoming Biochemical Diversity in AL Amyloidosis

Abstract Amyloid fibril deposition causes progressive tissue damage and organ failure in the systemic amyloid diseases, and therapies that suppress aggregation lead to clinical benefit. Small molecules that prevent aggregation by binding to precursor proteins are effective for amyloid transthyretin (ATTR) amyloidosis. However, in amyloid light chain (AL) amyloidosis, fibrils are formed by antibody light chains and every patient has a unique protein sequence that aggregates. The highly diverse sequences of these light chains appear to determine whether an individual is at risk of amyloidosis, the distribution of amyloid deposits and the progression of disease. Light chains are therefore challenging drug targets. This review explores the parallels between AL amyloidosis and ATTR amyloidosis to describe the discovery of small molecules that can stabilize light chains. These molecules have potential as therapies for AL amyloidosis, highlighting potential opportunities for drug discovery in other diseases of protein misfolding.