Multiple myeloma-associated AL amyloidosis: is a distinctive therapeutic approach warranted?

The natural history of multiple myeloma (MM) was revolutionized by the introduction of haematopoietic stem cell transplantation to the treatment armamentarium of this disease. Defined subgroups of MM patients (such as the elderly or dialysis-dependent) have required an individualized approach in order to minimize the transplant-related mortality. Little, however, is known about the management of 12-30% of MM patients with coexistent AL amyloidosis as the amyloidopathy is often overlooked and when recognized these patients commonly are excluded from clinical trials. While occult amyloidosis appears to have no impact on the toxicity and outcome of MM patients, the presence of symptomatic amyloidopathy clearly worsens their prognosis. Use of induction chemotherapy drugs that can cause further damage to the heart (Adriamycin), nervous system (Vincristine) or kidneys should be avoided as should lengthy delays in proceeding to autograft. Further, refining the transplant eligibility criteria for this subgroup of patients with co-existent amyloidopathy to include the number of organs involved and the degree of cardiac involvement (NYHA class, Troponins and NT-pro-BNP levels) along with melphalan dose-adjustment will minimize the treatment-related toxicity and mortality and possibly allow a reversal of the organ damage induced by the amyloidogenic light chain.