AL amyloidosis: from molecular mechanisms to targeted therapies.

Systemic amyloidosis is caused by misfolding and extracellular deposition of circulating proteins as amyloid fibrils, resulting in the dysfunction of vital organs. The most common systemic amyloidosis, light-chain (AL) amyloidosis, is caused by misfolded light chains produced by a small, dangerous B-cell clone. The process of amyloid formation, organ targeting, and damage is multifaceted and, after disease initiation, the complexity of the downstream pathogenic cascade increases, rendering its control a challenge. Because of the progressive nature of the disease, early diagnosis to prevent end-stage organ damage is vital. Improving awareness and systematic use of biomarkers of organ damage in screening populations at risk may improve the still unsatisfactory diagnostic process. Amyloid imaging is now emerging as an important companion of biomarkers in formulating the diagnosis and prognosis and monitoring the effects of therapy. An accurate diagnosis is the basis for appropriate therapy that is risk-adapted and response-tailored. Effective treatments targeting the clone and rapidly and profoundly reducing the amyloid light chains have produced marked improvements in overall survival, making AL amyloidosis the most successful model of all amyloidoses. New therapies targeting the amyloid deposits are now under development, together with novel agents modulating light chain aggregation and proteotoxicity. The future of AL amyloidosis treatment is combination therapy and will require an innovative collaborative model for a rapid translation from bench to bedside with the ultimate aim of achieving a cure for this complex disease.