Future directions in the clinical management of amyloid light-chain amyloidosis.

Amyloid light-chain (AL) amyloidosis results from extracellular deposition of fibril-forming monoclonal immunoglobulin light chains (LCs) usually secreted by a plasma cell (PC) clone. Misfolded LCs deposit as unique fibrils leading to organ failure and eventually death. Survival for untreated patients remains poor, and restrictive cardiomyopathy, nephrotic syndrome or hepatic failure greatly worsen outcome. Conventional chemotherapy and novel therapy with immunomodulatory drugs or proteasome inhibitors (PIs) eradicate PCs but generate adverse toxicities, and sustained responses are limited. Moreover, only 20% of patients with AL amyloidosis are eligible for stem cell transplant. The molecular events deregulated in AL amyloidosis remain undefined, and effective therapies based upon the biology of the disease are lacking. Impressive hematologic response rates obtained with bortezomib provide practice-changing data to advocate their introduction early in the treatment course. Bortezomib and the emerging second-generation PIs alone or combined with dexamethasone and alkylating agents may enhance hematologic and organ responses in AL amyloidosis.